Merge tag 'linux-can-next-for-5.13-20210413' of...

Merge tag 'linux-can-next-for-5.13-20210413' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can-next

Marc Kleine-Budde says:

====================
pull-request: can-next 2021-04-13

this is a pull request of 14 patches for net-next/master.

The first patch is by Yoshihiro Shimoda and updates the DT bindings
for the rcar_can driver.

Vincent Mailhol contributes 3 patches that add support for several
ETAS USB CAN adapters.

The final 10 patches are by me and clean up the peak_usb CAN driver.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/can/rcar_can.txt

@@ -19,7 +19,8 @@ Required properties:
 	      "renesas,can-r8a7793" if CAN controller is a part of R8A7793 SoC.
 	      "renesas,can-r8a7794" if CAN controller is a part of R8A7794 SoC.
 	      "renesas,can-r8a7795" if CAN controller is a part of R8A7795 SoC.
-	      "renesas,can-r8a7796" if CAN controller is a part of R8A7796 SoC.
+	      "renesas,can-r8a7796" if CAN controller is a part of R8A77960 SoC.
+	      "renesas,can-r8a77961" if CAN controller is a part of R8A77961 SoC.
 	      "renesas,can-r8a77965" if CAN controller is a part of R8A77965 SoC.
 	      "renesas,can-r8a77990" if CAN controller is a part of R8A77990 SoC.
 	      "renesas,can-r8a77995" if CAN controller is a part of R8A77995 SoC.
@@ -40,7 +41,7 @@ Required properties:
 - pinctrl-names: must be "default".
 
 Required properties for R8A774A1, R8A774B1, R8A774C0, R8A774E1, R8A7795,
-R8A7796, R8A77965, R8A77990, and R8A77995:
+R8A77960, R8A77961, R8A77965, R8A77990, and R8A77995:
 For the denoted SoCs, "clkp2" can be CANFD clock. This is a div6 clock and can
 be used by both CAN and CAN FD controller at the same time. It needs to be
 scaled to maximum frequency if any of these controllers use it. This is done

drivers/net/can/usb/Kconfig

@@ -20,6 +20,16 @@ config CAN_ESD_USB2
 	  This driver supports the CAN-USB/2 interface
 	  from esd electronic system design gmbh (http://www.esd.eu).
 
+config CAN_ETAS_ES58X
+	tristate "ETAS ES58X CAN/USB interfaces"
+	select CRC16
+	help
+	  This driver supports the ES581.4, ES582.1 and ES584.1 interfaces
+	  from ETAS GmbH (https://www.etas.com/en/products/es58x.php).
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called etas_es58x.
+
 config CAN_GS_USB
 	tristate "Geschwister Schneider UG interfaces"
 	help

drivers/net/can/usb/Makefile

@@ -6,6 +6,7 @@
 obj-$(CONFIG_CAN_8DEV_USB) += usb_8dev.o
 obj-$(CONFIG_CAN_EMS_USB) += ems_usb.o
 obj-$(CONFIG_CAN_ESD_USB2) += esd_usb2.o
+obj-$(CONFIG_CAN_ETAS_ES58X) += etas_es58x/
 obj-$(CONFIG_CAN_GS_USB) += gs_usb.o
 obj-$(CONFIG_CAN_KVASER_USB) += kvaser_usb/
 obj-$(CONFIG_CAN_MCBA_USB) += mcba_usb.o

drivers/net/can/usb/etas_es58x/Makefile

+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_CAN_ETAS_ES58X) += etas_es58x.o
+etas_es58x-y = es58x_core.o es581_4.o es58x_fd.o

drivers/net/can/usb/etas_es58x/es581_4.c

+// SPDX-License-Identifier: GPL-2.0
+
+/* Driver for ETAS GmbH ES58X USB CAN(-FD) Bus Interfaces.
+ *
+ * File es581_4.c: Adds support to ETAS ES581.4.
+ *
+ * Copyright (c) 2019 Robert Bosch Engineering and Business Solutions. All rights reserved.
+ * Copyright (c) 2020 ETAS K.K.. All rights reserved.
+ * Copyright (c) 2020, 2021 Vincent Mailhol <mailhol.vincent@wanadoo.fr>
+ */
+
+#include <linux/kernel.h>
+#include <asm/unaligned.h>
+
+#include "es58x_core.h"
+#include "es581_4.h"
+
+/**
+ * es581_4_sizeof_rx_tx_msg() - Calculate the actual length of the
+ *	structure of a rx or tx message.
+ * @msg: message of variable length, must have a dlc field.
+ *
+ * Even if RTR frames have actually no payload, the ES58X devices
+ * still expect it. Must be a macro in order to accept several types
+ * (struct es581_4_tx_can_msg and struct es581_4_rx_can_msg) as an
+ * input.
+ *
+ * Return: length of the message.
+ */
+#define es581_4_sizeof_rx_tx_msg(msg)				\
+	offsetof(typeof(msg), data[can_cc_dlc2len((msg).dlc)])
+
+static u16 es581_4_get_msg_len(const union es58x_urb_cmd *urb_cmd)
+{
+	return get_unaligned_le16(&urb_cmd->es581_4_urb_cmd.msg_len);
+}
+
+static int es581_4_echo_msg(struct es58x_device *es58x_dev,
+			    const struct es581_4_urb_cmd *es581_4_urb_cmd)
+{
+	struct net_device *netdev;
+	const struct es581_4_bulk_echo_msg *bulk_echo_msg;
+	const struct es581_4_echo_msg *echo_msg;
+	u64 *tstamps = es58x_dev->timestamps;
+	u16 msg_len;
+	u32 first_packet_idx, packet_idx;
+	unsigned int dropped = 0;
+	int i, num_element, ret;
+
+	bulk_echo_msg = &es581_4_urb_cmd->bulk_echo_msg;
+	msg_len = get_unaligned_le16(&es581_4_urb_cmd->msg_len) -
+	    sizeof(bulk_echo_msg->channel_no);
+	num_element = es58x_msg_num_element(es58x_dev->dev,
+					    bulk_echo_msg->echo_msg, msg_len);
+	if (num_element <= 0)
+		return num_element;
+
+	ret = es58x_get_netdev(es58x_dev, bulk_echo_msg->channel_no,
+			       ES581_4_CHANNEL_IDX_OFFSET, &netdev);
+	if (ret)
+		return ret;
+
+	echo_msg = &bulk_echo_msg->echo_msg[0];
+	first_packet_idx = get_unaligned_le32(&echo_msg->packet_idx);
+	packet_idx = first_packet_idx;
+	for (i = 0; i < num_element; i++) {
+		u32 tmp_idx;
+
+		echo_msg = &bulk_echo_msg->echo_msg[i];
+		tmp_idx = get_unaligned_le32(&echo_msg->packet_idx);
+		if (tmp_idx == packet_idx - 1) {
+			if (net_ratelimit())
+				netdev_warn(netdev,
+					    "Received echo packet idx %u twice\n",
+					    packet_idx - 1);
+			dropped++;
+			continue;
+		}
+		if (tmp_idx != packet_idx) {
+			netdev_err(netdev, "Echo packet idx jumped from %u to %u\n",
+				   packet_idx - 1, echo_msg->packet_idx);
+			return -EBADMSG;
+		}
+
+		tstamps[i] = get_unaligned_le64(&echo_msg->timestamp);
+		packet_idx++;
+	}
+
+	netdev->stats.tx_dropped += dropped;
+	return es58x_can_get_echo_skb(netdev, first_packet_idx,
+				      tstamps, num_element - dropped);
+}
+
+static int es581_4_rx_can_msg(struct es58x_device *es58x_dev,
+			      const struct es581_4_urb_cmd *es581_4_urb_cmd,
+			      u16 msg_len)
+{
+	const struct device *dev = es58x_dev->dev;
+	struct net_device *netdev;
+	int pkts, num_element, channel_no, ret;
+
+	num_element = es58x_msg_num_element(dev, es581_4_urb_cmd->rx_can_msg,
+					    msg_len);
+	if (num_element <= 0)
+		return num_element;
+
+	channel_no = es581_4_urb_cmd->rx_can_msg[0].channel_no;
+	ret = es58x_get_netdev(es58x_dev, channel_no,
+			       ES581_4_CHANNEL_IDX_OFFSET, &netdev);
+	if (ret)
+		return ret;
+
+	if (!netif_running(netdev)) {
+		if (net_ratelimit())
+			netdev_info(netdev,
+				    "%s: %s is down, dropping %d rx packets\n",
+				    __func__, netdev->name, num_element);
+		netdev->stats.rx_dropped += num_element;
+		return 0;
+	}
+
+	for (pkts = 0; pkts < num_element; pkts++) {
+		const struct es581_4_rx_can_msg *rx_can_msg =
+		    &es581_4_urb_cmd->rx_can_msg[pkts];
+		u64 tstamp = get_unaligned_le64(&rx_can_msg->timestamp);
+		canid_t can_id = get_unaligned_le32(&rx_can_msg->can_id);
+
+		if (channel_no != rx_can_msg->channel_no)
+			return -EBADMSG;
+
+		ret = es58x_rx_can_msg(netdev, tstamp, rx_can_msg->data,
+				       can_id, rx_can_msg->flags,
+				       rx_can_msg->dlc);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+static int es581_4_rx_err_msg(struct es58x_device *es58x_dev,
+			      const struct es581_4_rx_err_msg *rx_err_msg)
+{
+	struct net_device *netdev;
+	enum es58x_err error = get_unaligned_le32(&rx_err_msg->error);
+	int ret;
+
+	ret = es58x_get_netdev(es58x_dev, rx_err_msg->channel_no,
+			       ES581_4_CHANNEL_IDX_OFFSET, &netdev);
+	if (ret)
+		return ret;
+
+	return es58x_rx_err_msg(netdev, error, 0,
+				get_unaligned_le64(&rx_err_msg->timestamp));
+}
+
+static int es581_4_rx_event_msg(struct es58x_device *es58x_dev,
+				const struct es581_4_rx_event_msg *rx_event_msg)
+{
+	struct net_device *netdev;
+	enum es58x_event event = get_unaligned_le32(&rx_event_msg->event);
+	int ret;
+
+	ret = es58x_get_netdev(es58x_dev, rx_event_msg->channel_no,
+			       ES581_4_CHANNEL_IDX_OFFSET, &netdev);
+	if (ret)
+		return ret;
+
+	return es58x_rx_err_msg(netdev, 0, event,
+				get_unaligned_le64(&rx_event_msg->timestamp));
+}
+
+static int es581_4_rx_cmd_ret_u32(struct es58x_device *es58x_dev,
+				  const struct es581_4_urb_cmd *es581_4_urb_cmd,
+				  enum es58x_ret_type ret_type)
+{
+	struct net_device *netdev;
+	const struct es581_4_rx_cmd_ret *rx_cmd_ret;
+	u16 msg_len = get_unaligned_le16(&es581_4_urb_cmd->msg_len);
+	int ret;
+
+	ret = es58x_check_msg_len(es58x_dev->dev,
+				  es581_4_urb_cmd->rx_cmd_ret, msg_len);
+	if (ret)
+		return ret;
+
+	rx_cmd_ret = &es581_4_urb_cmd->rx_cmd_ret;
+
+	ret = es58x_get_netdev(es58x_dev, rx_cmd_ret->channel_no,
+			       ES581_4_CHANNEL_IDX_OFFSET, &netdev);
+	if (ret)
+		return ret;
+
+	return es58x_rx_cmd_ret_u32(netdev, ret_type,
+				    get_unaligned_le32(&rx_cmd_ret->rx_cmd_ret_le32));
+}
+
+static int es581_4_tx_ack_msg(struct es58x_device *es58x_dev,
+			      const struct es581_4_urb_cmd *es581_4_urb_cmd)
+{
+	struct net_device *netdev;
+	const struct es581_4_tx_ack_msg *tx_ack_msg;
+	u16 msg_len = get_unaligned_le16(&es581_4_urb_cmd->msg_len);
+	int ret;
+
+	tx_ack_msg = &es581_4_urb_cmd->tx_ack_msg;
+	ret = es58x_check_msg_len(es58x_dev->dev, *tx_ack_msg, msg_len);
+	if (ret)
+		return ret;
+
+	if (tx_ack_msg->rx_cmd_ret_u8 != ES58X_RET_U8_OK)
+		return es58x_rx_cmd_ret_u8(es58x_dev->dev,
+					   ES58X_RET_TYPE_TX_MSG,
+					   tx_ack_msg->rx_cmd_ret_u8);
+
+	ret = es58x_get_netdev(es58x_dev, tx_ack_msg->channel_no,
+			       ES581_4_CHANNEL_IDX_OFFSET, &netdev);
+	if (ret)
+		return ret;
+
+	return es58x_tx_ack_msg(netdev,
+				get_unaligned_le16(&tx_ack_msg->tx_free_entries),
+				ES58X_RET_U32_OK);
+}
+
+static int es581_4_dispatch_rx_cmd(struct es58x_device *es58x_dev,
+				   const struct es581_4_urb_cmd *es581_4_urb_cmd)
+{
+	const struct device *dev = es58x_dev->dev;
+	u16 msg_len = get_unaligned_le16(&es581_4_urb_cmd->msg_len);
+	enum es581_4_rx_type rx_type = es581_4_urb_cmd->rx_can_msg[0].rx_type;
+	int ret = 0;
+
+	switch (rx_type) {
+	case ES581_4_RX_TYPE_MESSAGE:
+		return es581_4_rx_can_msg(es58x_dev, es581_4_urb_cmd, msg_len);
+
+	case ES581_4_RX_TYPE_ERROR:
+		ret = es58x_check_msg_len(dev, es581_4_urb_cmd->rx_err_msg,
+					  msg_len);
+		if (ret < 0)
+			return ret;
+		return es581_4_rx_err_msg(es58x_dev,
+					  &es581_4_urb_cmd->rx_err_msg);
+
+	case ES581_4_RX_TYPE_EVENT:
+		ret = es58x_check_msg_len(dev, es581_4_urb_cmd->rx_event_msg,
+					  msg_len);
+		if (ret < 0)
+			return ret;
+		return es581_4_rx_event_msg(es58x_dev,
+					    &es581_4_urb_cmd->rx_event_msg);
+
+	default:
+		dev_err(dev, "%s: Unknown rx_type 0x%02X\n", __func__, rx_type);
+		return -EBADRQC;
+	}
+}
+
+static int es581_4_handle_urb_cmd(struct es58x_device *es58x_dev,
+				  const union es58x_urb_cmd *urb_cmd)
+{
+	const struct es581_4_urb_cmd *es581_4_urb_cmd;
+	struct device *dev = es58x_dev->dev;
+	u16 msg_len = es581_4_get_msg_len(urb_cmd);
+	int ret;
+
+	es581_4_urb_cmd = &urb_cmd->es581_4_urb_cmd;
+
+	if (es581_4_urb_cmd->cmd_type != ES581_4_CAN_COMMAND_TYPE) {
+		dev_err(dev, "%s: Unknown command type (0x%02X)\n",
+			__func__, es581_4_urb_cmd->cmd_type);
+		return -EBADRQC;
+	}
+
+	switch ((enum es581_4_cmd_id)es581_4_urb_cmd->cmd_id) {
+	case ES581_4_CMD_ID_SET_BITTIMING:
+		return es581_4_rx_cmd_ret_u32(es58x_dev, es581_4_urb_cmd,
+					      ES58X_RET_TYPE_SET_BITTIMING);
+
+	case ES581_4_CMD_ID_ENABLE_CHANNEL:
+		return es581_4_rx_cmd_ret_u32(es58x_dev, es581_4_urb_cmd,
+					      ES58X_RET_TYPE_ENABLE_CHANNEL);
+
+	case ES581_4_CMD_ID_TX_MSG:
+		return es581_4_tx_ack_msg(es58x_dev, es581_4_urb_cmd);
+
+	case ES581_4_CMD_ID_RX_MSG:
+		return es581_4_dispatch_rx_cmd(es58x_dev, es581_4_urb_cmd);
+
+	case ES581_4_CMD_ID_RESET_RX:
+		ret = es581_4_rx_cmd_ret_u32(es58x_dev, es581_4_urb_cmd,
+					     ES58X_RET_TYPE_RESET_RX);
+		return ret;
+
+	case ES581_4_CMD_ID_RESET_TX:
+		ret = es581_4_rx_cmd_ret_u32(es58x_dev, es581_4_urb_cmd,
+					     ES58X_RET_TYPE_RESET_TX);
+		return ret;
+
+	case ES581_4_CMD_ID_DISABLE_CHANNEL:
+		return es581_4_rx_cmd_ret_u32(es58x_dev, es581_4_urb_cmd,
+					      ES58X_RET_TYPE_DISABLE_CHANNEL);
+
+	case ES581_4_CMD_ID_TIMESTAMP:
+		ret = es58x_check_msg_len(dev, es581_4_urb_cmd->timestamp,
+					  msg_len);
+		if (ret < 0)
+			return ret;
+		es58x_rx_timestamp(es58x_dev,
+				   get_unaligned_le64(&es581_4_urb_cmd->timestamp));
+		return 0;
+
+	case ES581_4_CMD_ID_ECHO:
+		return es581_4_echo_msg(es58x_dev, es581_4_urb_cmd);
+
+	case ES581_4_CMD_ID_DEVICE_ERR:
+		ret = es58x_check_msg_len(dev, es581_4_urb_cmd->rx_cmd_ret_u8,
+					  msg_len);
+		if (ret)
+			return ret;
+		return es58x_rx_cmd_ret_u8(dev, ES58X_RET_TYPE_DEVICE_ERR,
+					   es581_4_urb_cmd->rx_cmd_ret_u8);
+
+	default:
+		dev_warn(dev, "%s: Unexpected command ID: 0x%02X\n",
+			 __func__, es581_4_urb_cmd->cmd_id);
+		return -EBADRQC;
+	}
+}
+
+static void es581_4_fill_urb_header(union es58x_urb_cmd *urb_cmd, u8 cmd_type,
+				    u8 cmd_id, u8 channel_idx, u16 msg_len)
+{
+	struct es581_4_urb_cmd *es581_4_urb_cmd = &urb_cmd->es581_4_urb_cmd;
+
+	es581_4_urb_cmd->SOF = cpu_to_le16(es581_4_param.tx_start_of_frame);
+	es581_4_urb_cmd->cmd_type = cmd_type;
+	es581_4_urb_cmd->cmd_id = cmd_id;
+	es581_4_urb_cmd->msg_len = cpu_to_le16(msg_len);
+}
+
+static int es581_4_tx_can_msg(struct es58x_priv *priv,
+			      const struct sk_buff *skb)
+{
+	struct es58x_device *es58x_dev = priv->es58x_dev;
+	union es58x_urb_cmd *urb_cmd = priv->tx_urb->transfer_buffer;
+	struct es581_4_urb_cmd *es581_4_urb_cmd = &urb_cmd->es581_4_urb_cmd;
+	struct can_frame *cf = (struct can_frame *)skb->data;
+	struct es581_4_tx_can_msg *tx_can_msg;
+	u16 msg_len;
+	int ret;
+
+	if (can_is_canfd_skb(skb))
+		return -EMSGSIZE;
+
+	if (priv->tx_can_msg_cnt == 0) {
+		msg_len = 1; /* struct es581_4_bulk_tx_can_msg:num_can_msg */
+		es581_4_fill_urb_header(urb_cmd, ES581_4_CAN_COMMAND_TYPE,
+					ES581_4_CMD_ID_TX_MSG,
+					priv->channel_idx, msg_len);
+		es581_4_urb_cmd->bulk_tx_can_msg.num_can_msg = 0;
+	} else {
+		msg_len = es581_4_get_msg_len(urb_cmd);
+	}
+
+	ret = es58x_check_msg_max_len(es58x_dev->dev,
+				      es581_4_urb_cmd->bulk_tx_can_msg,
+				      msg_len + sizeof(*tx_can_msg));
+	if (ret)
+		return ret;
+
+	/* Fill message contents. */
+	tx_can_msg = (struct es581_4_tx_can_msg *)
+	    &es581_4_urb_cmd->bulk_tx_can_msg.tx_can_msg_buf[msg_len - 1];
+	put_unaligned_le32(es58x_get_raw_can_id(cf), &tx_can_msg->can_id);
+	put_unaligned_le32(priv->tx_head, &tx_can_msg->packet_idx);
+	put_unaligned_le16((u16)es58x_get_flags(skb), &tx_can_msg->flags);
+	tx_can_msg->channel_no = priv->channel_idx + ES581_4_CHANNEL_IDX_OFFSET;
+	tx_can_msg->dlc = can_get_cc_dlc(cf, priv->can.ctrlmode);
+
+	memcpy(tx_can_msg->data, cf->data, cf->len);
+
+	/* Calculate new sizes. */
+	es581_4_urb_cmd->bulk_tx_can_msg.num_can_msg++;
+	msg_len += es581_4_sizeof_rx_tx_msg(*tx_can_msg);
+	priv->tx_urb->transfer_buffer_length = es58x_get_urb_cmd_len(es58x_dev,
+								     msg_len);
+	es581_4_urb_cmd->msg_len = cpu_to_le16(msg_len);
+
+	return 0;
+}
+
+static int es581_4_set_bittiming(struct es58x_priv *priv)
+{
+	struct es581_4_tx_conf_msg tx_conf_msg = { 0 };
+	struct can_bittiming *bt = &priv->can.bittiming;
+
+	tx_conf_msg.bitrate = cpu_to_le32(bt->bitrate);
+	/* bt->sample_point is in tenth of percent. Convert it to percent. */
+	tx_conf_msg.sample_point = cpu_to_le32(bt->sample_point / 10U);
+	tx_conf_msg.samples_per_bit = cpu_to_le32(ES58X_SAMPLES_PER_BIT_ONE);
+	tx_conf_msg.bit_time = cpu_to_le32(can_bit_time(bt));
+	tx_conf_msg.sjw = cpu_to_le32(bt->sjw);
+	tx_conf_msg.sync_edge = cpu_to_le32(ES58X_SYNC_EDGE_SINGLE);
+	tx_conf_msg.physical_layer =
+	    cpu_to_le32(ES58X_PHYSICAL_LAYER_HIGH_SPEED);
+	tx_conf_msg.echo_mode = cpu_to_le32(ES58X_ECHO_ON);
+	tx_conf_msg.channel_no = priv->channel_idx + ES581_4_CHANNEL_IDX_OFFSET;
+
+	return es58x_send_msg(priv->es58x_dev, ES581_4_CAN_COMMAND_TYPE,
+			      ES581_4_CMD_ID_SET_BITTIMING, &tx_conf_msg,
+			      sizeof(tx_conf_msg), priv->channel_idx);
+}
+
+static int es581_4_enable_channel(struct es58x_priv *priv)
+{
+	int ret;
+	u8 msg = priv->channel_idx + ES581_4_CHANNEL_IDX_OFFSET;
+
+	ret = es581_4_set_bittiming(priv);
+	if (ret)
+		return ret;
+
+	return es58x_send_msg(priv->es58x_dev, ES581_4_CAN_COMMAND_TYPE,
+			      ES581_4_CMD_ID_ENABLE_CHANNEL, &msg, sizeof(msg),
+			      priv->channel_idx);
+}
+
+static int es581_4_disable_channel(struct es58x_priv *priv)
+{
+	u8 msg = priv->channel_idx + ES581_4_CHANNEL_IDX_OFFSET;
+
+	return es58x_send_msg(priv->es58x_dev, ES581_4_CAN_COMMAND_TYPE,
+			      ES581_4_CMD_ID_DISABLE_CHANNEL, &msg, sizeof(msg),
+			      priv->channel_idx);
+}
+
+static int es581_4_reset_device(struct es58x_device *es58x_dev)
+{
+	return es58x_send_msg(es58x_dev, ES581_4_CAN_COMMAND_TYPE,
+			      ES581_4_CMD_ID_RESET_DEVICE,
+			      ES58X_EMPTY_MSG, 0, ES58X_CHANNEL_IDX_NA);
+}
+
+static int es581_4_get_timestamp(struct es58x_device *es58x_dev)
+{
+	return es58x_send_msg(es58x_dev, ES581_4_CAN_COMMAND_TYPE,
+			      ES581_4_CMD_ID_TIMESTAMP,
+			      ES58X_EMPTY_MSG, 0, ES58X_CHANNEL_IDX_NA);
+}
+
+/* Nominal bittiming constants for ES581.4 as specified in the
+ * microcontroller datasheet: "Stellaris(R) LM3S5B91 Microcontroller"
+ * table 17-4 "CAN Protocol Ranges" from Texas Instruments.
+ */
+static const struct can_bittiming_const es581_4_bittiming_const = {
+	.name = "ES581.4",
+	.tseg1_min = 1,
+	.tseg1_max = 8,
+	.tseg2_min = 1,
+	.tseg2_max = 8,
+	.sjw_max = 4,
+	.brp_min = 1,
+	.brp_max = 128,
+	.brp_inc = 1
+};
+
+const struct es58x_parameters es581_4_param = {
+	.bittiming_const = &es581_4_bittiming_const,
+	.data_bittiming_const = NULL,
+	.tdc_const = NULL,
+	.bitrate_max = 1 * CAN_MBPS,
+	.clock = {.freq = 50 * CAN_MHZ},
+	.ctrlmode_supported = CAN_CTRLMODE_CC_LEN8_DLC,
+	.tx_start_of_frame = 0xAFAF,
+	.rx_start_of_frame = 0xFAFA,
+	.tx_urb_cmd_max_len = ES581_4_TX_URB_CMD_MAX_LEN,
+	.rx_urb_cmd_max_len = ES581_4_RX_URB_CMD_MAX_LEN,
+	/* Size of internal device TX queue is 330.
+	 *
+	 * However, we witnessed some ES58X_ERR_PROT_CRC errors from
+	 * the device and thus, echo_skb_max was lowered to the
+	 * empirical value of 75 which seems stable and then rounded
+	 * down to become a power of two.
+	 *
+	 * Root cause of those ES58X_ERR_PROT_CRC errors is still
+	 * unclear.
+	 */
+	.fifo_mask = 63, /* echo_skb_max = 64 */
+	.dql_min_limit = CAN_FRAME_LEN_MAX * 50, /* Empirical value. */
+	.tx_bulk_max = ES581_4_TX_BULK_MAX,
+	.urb_cmd_header_len = ES581_4_URB_CMD_HEADER_LEN,
+	.rx_urb_max = ES58X_RX_URBS_MAX,
+	.tx_urb_max = ES58X_TX_URBS_MAX
+};
+
+const struct es58x_operators es581_4_ops = {
+	.get_msg_len = es581_4_get_msg_len,
+	.handle_urb_cmd = es581_4_handle_urb_cmd,
+	.fill_urb_header = es581_4_fill_urb_header,
+	.tx_can_msg = es581_4_tx_can_msg,
+	.enable_channel = es581_4_enable_channel,
+	.disable_channel = es581_4_disable_channel,
+	.reset_device = es581_4_reset_device,
+	.get_timestamp = es581_4_get_timestamp
+};

drivers/net/can/usb/etas_es58x/es581_4.h

+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* Driver for ETAS GmbH ES58X USB CAN(-FD) Bus Interfaces.
+ *
+ * File es581_4.h: Definitions and declarations specific to ETAS
+ * ES581.4.
+ *
+ * Copyright (c) 2019 Robert Bosch Engineering and Business Solutions. All rights reserved.
+ * Copyright (c) 2020 ETAS K.K.. All rights reserved.
+ * Copyright (c) 2020, 2021 Vincent Mailhol <mailhol.vincent@wanadoo.fr>
+ */
+
+#ifndef __ES581_4_H__
+#define __ES581_4_H__
+
+#include <linux/types.h>
+
+#define ES581_4_NUM_CAN_CH 2
+#define ES581_4_CHANNEL_IDX_OFFSET 1
+
+#define ES581_4_TX_BULK_MAX 25
+#define ES581_4_RX_BULK_MAX 30
+#define ES581_4_ECHO_BULK_MAX 30
+
+enum es581_4_cmd_type {
+	ES581_4_CAN_COMMAND_TYPE = 0x45
+};
+
+enum es581_4_cmd_id {
+	ES581_4_CMD_ID_OPEN_CHANNEL = 0x01,
+	ES581_4_CMD_ID_CLOSE_CHANNEL = 0x02,
+	ES581_4_CMD_ID_SET_BITTIMING = 0x03,
+	ES581_4_CMD_ID_ENABLE_CHANNEL = 0x04,
+	ES581_4_CMD_ID_TX_MSG = 0x05,
+	ES581_4_CMD_ID_RX_MSG = 0x06,
+	ES581_4_CMD_ID_RESET_RX = 0x0A,
+	ES581_4_CMD_ID_RESET_TX = 0x0B,
+	ES581_4_CMD_ID_DISABLE_CHANNEL = 0x0C,
+	ES581_4_CMD_ID_TIMESTAMP = 0x0E,
+	ES581_4_CMD_ID_RESET_DEVICE = 0x28,
+	ES581_4_CMD_ID_ECHO = 0x71,
+	ES581_4_CMD_ID_DEVICE_ERR = 0x72
+};
+
+enum es581_4_rx_type {
+	ES581_4_RX_TYPE_MESSAGE = 1,
+	ES581_4_RX_TYPE_ERROR = 3,
+	ES581_4_RX_TYPE_EVENT = 4
+};
+
+/**
+ * struct es581_4_tx_conf_msg - Channel configuration.
+ * @bitrate: Bitrate.
+ * @sample_point: Sample point is in percent [0..100].
+ * @samples_per_bit: type enum es58x_samples_per_bit.
+ * @bit_time: Number of time quanta in one bit.
+ * @sjw: Synchronization Jump Width.
+ * @sync_edge: type enum es58x_sync_edge.
+ * @physical_layer: type enum es58x_physical_layer.
+ * @echo_mode: type enum es58x_echo_mode.
+ * @channel_no: Channel number, starting from 1. Not to be confused
+ *	with channed_idx of the ES58X FD which starts from 0.
+ */
+struct es581_4_tx_conf_msg {
+	__le32 bitrate;
+	__le32 sample_point;
+	__le32 samples_per_bit;
+	__le32 bit_time;
+	__le32 sjw;
+	__le32 sync_edge;
+	__le32 physical_layer;
+	__le32 echo_mode;
+	u8 channel_no;
+} __packed;
+
+struct es581_4_tx_can_msg {
+	__le32 can_id;
+	__le32 packet_idx;
+	__le16 flags;
+	u8 channel_no;
+	u8 dlc;
+	u8 data[CAN_MAX_DLEN];
+} __packed;
+
+/* The ES581.4 allows bulk transfer.  */
+struct es581_4_bulk_tx_can_msg {
+	u8 num_can_msg;
+	/* Using type "u8[]" instead of "struct es581_4_tx_can_msg[]"
+	 * for tx_msg_buf because each member has a flexible size.
+	 */
+	u8 tx_can_msg_buf[ES581_4_TX_BULK_MAX *
+			  sizeof(struct es581_4_tx_can_msg)];
+} __packed;
+
+struct es581_4_echo_msg {
+	__le64 timestamp;
+	__le32 packet_idx;
+} __packed;
+
+struct es581_4_bulk_echo_msg {
+	u8 channel_no;
+	struct es581_4_echo_msg echo_msg[ES581_4_ECHO_BULK_MAX];
+} __packed;
+
+/* Normal Rx CAN Message */
+struct es581_4_rx_can_msg {
+	__le64 timestamp;
+	u8 rx_type;		/* type enum es581_4_rx_type */
+	u8 flags;		/* type enum es58x_flag */
+	u8 channel_no;
+	u8 dlc;
+	__le32 can_id;
+	u8 data[CAN_MAX_DLEN];
+} __packed;
+
+struct es581_4_rx_err_msg {
+	__le64 timestamp;
+	__le16 rx_type;		/* type enum es581_4_rx_type */
+	__le16 flags;		/* type enum es58x_flag */
+	u8 channel_no;
+	u8 __padding[2];
+	u8 dlc;
+	__le32 tag;		/* Related to the CAN filtering. Unused in this module */
+	__le32 can_id;
+	__le32 error;		/* type enum es58x_error */
+	__le32 destination;	/* Unused in this module */
+} __packed;
+
+struct es581_4_rx_event_msg {
+	__le64 timestamp;
+	__le16 rx_type;		/* type enum es581_4_rx_type */
+	u8 channel_no;
+	u8 __padding;
+	__le32 tag;		/* Related to the CAN filtering. Unused in this module */
+	__le32 event;		/* type enum es58x_event */
+	__le32 destination;	/* Unused in this module */
+} __packed;
+
+struct es581_4_tx_ack_msg {
+	__le16 tx_free_entries;	/* Number of remaining free entries in the device TX queue */
+	u8 channel_no;
+	u8 rx_cmd_ret_u8;	/* type enum es58x_cmd_ret_code_u8 */
+} __packed;
+
+struct es581_4_rx_cmd_ret {
+	__le32 rx_cmd_ret_le32;
+	u8 channel_no;
+	u8 __padding[3];
+} __packed;
+
+/**
+ * struct es581_4_urb_cmd - Commands received from or sent to the
+ *	ES581.4 device.
+ * @SOF: Start of Frame.
+ * @cmd_type: Command Type (type: enum es581_4_cmd_type). The CRC
+ *	calculation starts at this position.
+ * @cmd_id: Command ID (type: enum es581_4_cmd_id).
+ * @msg_len: Length of the message, excluding CRC (i.e. length of the
+ *	union).
+ * @tx_conf_msg: Channel configuration.
+ * @bulk_tx_can_msg: Tx messages.
+ * @rx_can_msg: Array of Rx messages.
+ * @bulk_echo_msg: Tx message being looped back.
+ * @rx_err_msg: Error message.
+ * @rx_event_msg: Event message.
+ * @tx_ack_msg: Tx acknowledgment message.
+ * @rx_cmd_ret: Command return code.
+ * @timestamp: Timestamp reply.
+ * @rx_cmd_ret_u8: Rx 8 bits return code (type: enum
+ *	es58x_cmd_ret_code_u8).
+ * @raw_msg: Message raw payload.
+ * @reserved_for_crc16_do_not_use: The structure ends with a
+ *	CRC16. Because the structures in above union are of variable
+ *	lengths, we can not predict the offset of the CRC in
+ *	advance. Use functions es58x_get_crc() and es58x_set_crc() to
+ *	manipulate it.
+ */
+struct es581_4_urb_cmd {
+	__le16 SOF;
+	u8 cmd_type;
+	u8 cmd_id;
+	__le16 msg_len;
+
+	union {
+		struct es581_4_tx_conf_msg tx_conf_msg;
+		struct es581_4_bulk_tx_can_msg bulk_tx_can_msg;
+		struct es581_4_rx_can_msg rx_can_msg[ES581_4_RX_BULK_MAX];
+		struct es581_4_bulk_echo_msg bulk_echo_msg;
+		struct es581_4_rx_err_msg rx_err_msg;
+		struct es581_4_rx_event_msg rx_event_msg;
+		struct es581_4_tx_ack_msg tx_ack_msg;
+		struct es581_4_rx_cmd_ret rx_cmd_ret;
+		__le64 timestamp;
+		u8 rx_cmd_ret_u8;
+		u8 raw_msg[0];
+	} __packed;
+
+	__le16 reserved_for_crc16_do_not_use;
+} __packed;
+
+#define ES581_4_URB_CMD_HEADER_LEN (offsetof(struct es581_4_urb_cmd, raw_msg))
+#define ES581_4_TX_URB_CMD_MAX_LEN					\
+	ES58X_SIZEOF_URB_CMD(struct es581_4_urb_cmd, bulk_tx_can_msg)
+#define ES581_4_RX_URB_CMD_MAX_LEN					\
+	ES58X_SIZEOF_URB_CMD(struct es581_4_urb_cmd, rx_can_msg)
+
+#endif /* __ES581_4_H__ */

drivers/net/can/usb/etas_es58x/es58x_core.c

+// SPDX-License-Identifier: GPL-2.0
+
+/* Driver for ETAS GmbH ES58X USB CAN(-FD) Bus Interfaces.
+ *
+ * File es58x_core.c: Core logic to manage the network devices and the
+ * USB interface.
+ *
+ * Copyright (c) 2019 Robert Bosch Engineering and Business Solutions. All rights reserved.
+ * Copyright (c) 2020 ETAS K.K.. All rights reserved.
+ * Copyright (c) 2020, 2021 Vincent Mailhol <mailhol.vincent@wanadoo.fr>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/crc16.h>
+#include <asm/unaligned.h>
+
+#include "es58x_core.h"
+
+#define DRV_VERSION "1.00"
+MODULE_AUTHOR("Mailhol Vincent <mailhol.vincent@wanadoo.fr>");
+MODULE_AUTHOR("Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>");
+MODULE_DESCRIPTION("Socket CAN driver for ETAS ES58X USB adapters");
+MODULE_VERSION(DRV_VERSION);
+MODULE_LICENSE("GPL v2");
+
+#define ES58X_MODULE_NAME "etas_es58x"
+#define ES58X_VENDOR_ID 0x108C
+#define ES581_4_PRODUCT_ID 0x0159
+#define ES582_1_PRODUCT_ID 0x0168
+#define ES584_1_PRODUCT_ID 0x0169
+
+/* ES58X FD has some interface protocols unsupported by this driver. */
+#define ES58X_FD_INTERFACE_PROTOCOL 0
+
+/* Table of devices which work with this driver. */
+static const struct usb_device_id es58x_id_table[] = {
+	{
+		/* ETAS GmbH ES581.4 USB dual-channel CAN Bus Interface module. */
+		USB_DEVICE(ES58X_VENDOR_ID, ES581_4_PRODUCT_ID),
+		.driver_info = ES58X_DUAL_CHANNEL
+	}, {
+		/* ETAS GmbH ES582.1 USB dual-channel CAN FD Bus Interface module. */
+		USB_DEVICE_INTERFACE_PROTOCOL(ES58X_VENDOR_ID, ES582_1_PRODUCT_ID,
+					      ES58X_FD_INTERFACE_PROTOCOL),
+		.driver_info = ES58X_DUAL_CHANNEL | ES58X_FD_FAMILY
+	}, {
+		/* ETAS GmbH ES584.1 USB single-channel CAN FD Bus Interface module. */
+		USB_DEVICE_INTERFACE_PROTOCOL(ES58X_VENDOR_ID, ES584_1_PRODUCT_ID,
+					      ES58X_FD_INTERFACE_PROTOCOL),
+		.driver_info = ES58X_FD_FAMILY
+	}, {
+		/* Terminating entry */
+	}
+};
+
+MODULE_DEVICE_TABLE(usb, es58x_id_table);
+
+#define es58x_print_hex_dump(buf, len)					\
+	print_hex_dump(KERN_DEBUG,					\
+		       ES58X_MODULE_NAME " " __stringify(buf) ": ",	\
+		       DUMP_PREFIX_NONE, 16, 1, buf, len, false)
+
+#define es58x_print_hex_dump_debug(buf, len)				 \
+	print_hex_dump_debug(ES58X_MODULE_NAME " " __stringify(buf) ": ",\
+			     DUMP_PREFIX_NONE, 16, 1, buf, len, false)
+
+/* The last two bytes of an ES58X command is a CRC16. The first two
+ * bytes (the start of frame) are skipped and the CRC calculation
+ * starts on the third byte.
+ */
+#define ES58X_CRC_CALC_OFFSET 2
+
+/**
+ * es58x_calculate_crc() - Compute the crc16 of a given URB.
+ * @urb_cmd: The URB command for which we want to calculate the CRC.
+ * @urb_len: Length of @urb_cmd. Must be at least bigger than 4
+ *	(ES58X_CRC_CALC_OFFSET + sizeof(crc))
+ *
+ * Return: crc16 value.
+ */
+static u16 es58x_calculate_crc(const union es58x_urb_cmd *urb_cmd, u16 urb_len)
+{
+	u16 crc;
+	ssize_t len = urb_len - ES58X_CRC_CALC_OFFSET - sizeof(crc);
+
+	crc = crc16(0, &urb_cmd->raw_cmd[ES58X_CRC_CALC_OFFSET], len);
+	return crc;
+}
+
+/**
+ * es58x_get_crc() - Get the CRC value of a given URB.
+ * @urb_cmd: The URB command for which we want to get the CRC.
+ * @urb_len: Length of @urb_cmd. Must be at least bigger than 4
+ *	(ES58X_CRC_CALC_OFFSET + sizeof(crc))
+ *
+ * Return: crc16 value.
+ */
+static u16 es58x_get_crc(const union es58x_urb_cmd *urb_cmd, u16 urb_len)
+{
+	u16 crc;
+	const __le16 *crc_addr;
+
+	crc_addr = (__le16 *)&urb_cmd->raw_cmd[urb_len - sizeof(crc)];
+	crc = get_unaligned_le16(crc_addr);
+	return crc;
+}
+
+/**
+ * es58x_set_crc() - Set the CRC value of a given URB.
+ * @urb_cmd: The URB command for which we want to get the CRC.
+ * @urb_len: Length of @urb_cmd. Must be at least bigger than 4
+ *	(ES58X_CRC_CALC_OFFSET + sizeof(crc))
+ */
+static void es58x_set_crc(union es58x_urb_cmd *urb_cmd, u16 urb_len)
+{
+	u16 crc;
+	__le16 *crc_addr;
+
+	crc = es58x_calculate_crc(urb_cmd, urb_len);
+	crc_addr = (__le16 *)&urb_cmd->raw_cmd[urb_len - sizeof(crc)];
+	put_unaligned_le16(crc, crc_addr);
+}
+
+/**
+ * es58x_check_crc() - Validate the CRC value of a given URB.
+ * @es58x_dev: ES58X device.
+ * @urb_cmd: The URB command for which we want to check the CRC.
+ * @urb_len: Length of @urb_cmd. Must be at least bigger than 4
+ *	(ES58X_CRC_CALC_OFFSET + sizeof(crc))
+ *
+ * Return: zero on success, -EBADMSG if the CRC check fails.
+ */
+static int es58x_check_crc(struct es58x_device *es58x_dev,
+			   const union es58x_urb_cmd *urb_cmd, u16 urb_len)
+{
+	u16 calculated_crc = es58x_calculate_crc(urb_cmd, urb_len);
+	u16 expected_crc = es58x_get_crc(urb_cmd, urb_len);
+
+	if (expected_crc != calculated_crc) {
+		dev_err_ratelimited(es58x_dev->dev,
+				    "%s: Bad CRC, urb_len: %d\n",
+				    __func__, urb_len);
+		return -EBADMSG;
+	}
+
+	return 0;
+}
+
+/**
+ * es58x_timestamp_to_ns() - Convert a timestamp value received from a
+ *	ES58X device to nanoseconds.
+ * @timestamp: Timestamp received from a ES58X device.
+ *
+ * The timestamp received from ES58X is expressed in multiples of 0.5
+ * micro seconds. This function converts it in to nanoseconds.
+ *
+ * Return: Timestamp value in nanoseconds.
+ */
+static u64 es58x_timestamp_to_ns(u64 timestamp)
+{
+	const u64 es58x_timestamp_ns_mult_coef = 500ULL;
+
+	return es58x_timestamp_ns_mult_coef * timestamp;
+}
+
+/**
+ * es58x_set_skb_timestamp() - Set the hardware timestamp of an skb.
+ * @netdev: CAN network device.
+ * @skb: socket buffer of a CAN message.
+ * @timestamp: Timestamp received from an ES58X device.
+ *
+ * Used for both received and echo messages.
+ */
+static void es58x_set_skb_timestamp(struct net_device *netdev,
+				    struct sk_buff *skb, u64 timestamp)
+{
+	struct es58x_device *es58x_dev = es58x_priv(netdev)->es58x_dev;
+	struct skb_shared_hwtstamps *hwts;
+
+	hwts = skb_hwtstamps(skb);
+	/* Ignoring overflow (overflow on 64 bits timestamp with nano
+	 * second precision would occur after more than 500 years).
+	 */
+	hwts->hwtstamp = ns_to_ktime(es58x_timestamp_to_ns(timestamp) +
+				     es58x_dev->realtime_diff_ns);
+}
+
+/**
+ * es58x_rx_timestamp() - Handle a received timestamp.
+ * @es58x_dev: ES58X device.
+ * @timestamp: Timestamp received from a ES58X device.
+ *
+ * Calculate the difference between the ES58X device and the kernel
+ * internal clocks. This difference will be later used as an offset to
+ * convert the timestamps of RX and echo messages to match the kernel
+ * system time (e.g. convert to UNIX time).
+ */
+void es58x_rx_timestamp(struct es58x_device *es58x_dev, u64 timestamp)
+{
+	u64 ktime_real_ns = ktime_get_real_ns();
+	u64 device_timestamp = es58x_timestamp_to_ns(timestamp);
+
+	dev_dbg(es58x_dev->dev, "%s: request round-trip time: %llu ns\n",
+		__func__, ktime_real_ns - es58x_dev->ktime_req_ns);
+
+	es58x_dev->realtime_diff_ns =
+	    (es58x_dev->ktime_req_ns + ktime_real_ns) / 2 - device_timestamp;
+	es58x_dev->ktime_req_ns = 0;
+
+	dev_dbg(es58x_dev->dev,
+		"%s: Device timestamp: %llu, diff with kernel: %llu\n",
+		__func__, device_timestamp, es58x_dev->realtime_diff_ns);
+}
+
+/**
+ * es58x_set_realtime_diff_ns() - Calculate difference between the
+ *	clocks of the ES58X device and the kernel
+ * @es58x_dev: ES58X device.
+ *
+ * Request a timestamp from the ES58X device. Once the answer is
+ * received, the timestamp difference will be set by the callback
+ * function es58x_rx_timestamp().
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_set_realtime_diff_ns(struct es58x_device *es58x_dev)
+{
+	if (es58x_dev->ktime_req_ns) {
+		dev_warn(es58x_dev->dev,
+			 "%s: Previous request to set timestamp has not completed yet\n",
+			 __func__);
+		return -EBUSY;
+	}
+
+	es58x_dev->ktime_req_ns = ktime_get_real_ns();
+	return es58x_dev->ops->get_timestamp(es58x_dev);
+}
+
+/**
+ * es58x_is_can_state_active() - Is the network device in an active
+ *	CAN state?
+ * @netdev: CAN network device.
+ *
+ * The device is considered active if it is able to send or receive
+ * CAN frames, that is to say if it is in any of
+ * CAN_STATE_ERROR_ACTIVE, CAN_STATE_ERROR_WARNING or
+ * CAN_STATE_ERROR_PASSIVE states.
+ *
+ * Caution: when recovering from a bus-off,
+ * net/core/dev.c#can_restart() will call
+ * net/core/dev.c#can_flush_echo_skb() without using any kind of
+ * locks. For this reason, it is critical to guarantee that no TX or
+ * echo operations (i.e. any access to priv->echo_skb[]) can be done
+ * while this function is returning false.
+ *
+ * Return: true if the device is active, else returns false.
+ */
+static bool es58x_is_can_state_active(struct net_device *netdev)
+{
+	return es58x_priv(netdev)->can.state < CAN_STATE_BUS_OFF;
+}
+
+/**
+ * es58x_is_echo_skb_threshold_reached() - Determine the limit of how
+ *	many skb slots can be taken before we should stop the network
+ *	queue.
+ * @priv: ES58X private parameters related to the network device.
+ *
+ * We need to save enough free skb slots in order to be able to do
+ * bulk send. This function can be used to determine when to wake or
+ * stop the network queue in regard to the number of skb slots already
+ * taken if the echo FIFO.
+ *
+ * Return: boolean.
+ */
+static bool es58x_is_echo_skb_threshold_reached(struct es58x_priv *priv)
+{
+	u32 num_echo_skb =  priv->tx_head - priv->tx_tail;
+	u32 threshold = priv->can.echo_skb_max -
+		priv->es58x_dev->param->tx_bulk_max + 1;
+
+	return num_echo_skb >= threshold;
+}
+
+/**
+ * es58x_can_free_echo_skb_tail() - Remove the oldest echo skb of the
+ *	echo FIFO.
+ * @netdev: CAN network device.
+ *
+ * Naming convention: the tail is the beginning of the FIFO, i.e. the
+ * first skb to have entered the FIFO.
+ */
+static void es58x_can_free_echo_skb_tail(struct net_device *netdev)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	u16 fifo_mask = priv->es58x_dev->param->fifo_mask;
+	unsigned int frame_len = 0;
+
+	can_free_echo_skb(netdev, priv->tx_tail & fifo_mask, &frame_len);
+	netdev_completed_queue(netdev, 1, frame_len);
+
+	priv->tx_tail++;
+
+	netdev->stats.tx_dropped++;
+}
+
+/**
+ * es58x_can_get_echo_skb_recovery() - Try to re-sync the echo FIFO.
+ * @netdev: CAN network device.
+ * @rcv_packet_idx: Index
+ *
+ * This function should not be called under normal circumstances. In
+ * the unlikely case that one or several URB packages get dropped by
+ * the device, the index will get out of sync. Try to recover by
+ * dropping the echo skb packets with older indexes.
+ *
+ * Return: zero if recovery was successful, -EINVAL otherwise.
+ */
+static int es58x_can_get_echo_skb_recovery(struct net_device *netdev,
+					   u32 rcv_packet_idx)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	int ret = 0;
+
+	netdev->stats.tx_errors++;
+
+	if (net_ratelimit())
+		netdev_warn(netdev,
+			    "Bad echo packet index: %u. First index: %u, end index %u, num_echo_skb: %02u/%02u\n",
+			    rcv_packet_idx, priv->tx_tail, priv->tx_head,
+			    priv->tx_head - priv->tx_tail,
+			    priv->can.echo_skb_max);
+
+	if ((s32)(rcv_packet_idx - priv->tx_tail) < 0) {
+		if (net_ratelimit())
+			netdev_warn(netdev,
+				    "Received echo index is from the past. Ignoring it\n");
+		ret = -EINVAL;
+	} else if ((s32)(rcv_packet_idx - priv->tx_head) >= 0) {
+		if (net_ratelimit())
+			netdev_err(netdev,
+				   "Received echo index is from the future. Ignoring it\n");
+		ret = -EINVAL;
+	} else {
+		if (net_ratelimit())
+			netdev_warn(netdev,
+				    "Recovery: dropping %u echo skb from index %u to %u\n",
+				    rcv_packet_idx - priv->tx_tail,
+				    priv->tx_tail, rcv_packet_idx - 1);
+		while (priv->tx_tail != rcv_packet_idx) {
+			if (priv->tx_tail == priv->tx_head)
+				return -EINVAL;
+			es58x_can_free_echo_skb_tail(netdev);
+		}
+	}
+	return ret;
+}
+
+/**
+ * es58x_can_get_echo_skb() - Get the skb from the echo FIFO and loop
+ *	it back locally.
+ * @netdev: CAN network device.
+ * @rcv_packet_idx: Index of the first packet received from the device.
+ * @tstamps: Array of hardware timestamps received from a ES58X device.
+ * @pkts: Number of packets (and so, length of @tstamps).
+ *
+ * Callback function for when we receive a self reception
+ * acknowledgment.  Retrieves the skb from the echo FIFO, sets its
+ * hardware timestamp (the actual time it was sent) and loops it back
+ * locally.
+ *
+ * The device has to be active (i.e. network interface UP and not in
+ * bus off state or restarting).
+ *
+ * Packet indexes must be consecutive (i.e. index of first packet is
+ * @rcv_packet_idx, index of second packet is @rcv_packet_idx + 1 and
+ * index of last packet is @rcv_packet_idx + @pkts - 1).
+ *
+ * Return: zero on success.
+ */
+int es58x_can_get_echo_skb(struct net_device *netdev, u32 rcv_packet_idx,
+			   u64 *tstamps, unsigned int pkts)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	unsigned int rx_total_frame_len = 0;
+	unsigned int num_echo_skb = priv->tx_head - priv->tx_tail;
+	int i;
+	u16 fifo_mask = priv->es58x_dev->param->fifo_mask;
+
+	if (!netif_running(netdev)) {
+		if (net_ratelimit())
+			netdev_info(netdev,
+				    "%s: %s is down, dropping %d echo packets\n",
+				    __func__, netdev->name, pkts);
+		netdev->stats.tx_dropped += pkts;
+		return 0;
+	} else if (!es58x_is_can_state_active(netdev)) {
+		if (net_ratelimit())
+			netdev_dbg(netdev,
+				   "Bus is off or device is restarting. Ignoring %u echo packets from index %u\n",
+				   pkts, rcv_packet_idx);
+		/* stats.tx_dropped will be (or was already)
+		 * incremented by
+		 * drivers/net/can/net/dev.c:can_flush_echo_skb().
+		 */
+		return 0;
+	} else if (num_echo_skb == 0) {
+		if (net_ratelimit())
+			netdev_warn(netdev,
+				    "Received %u echo packets from index: %u but echo skb queue is empty.\n",
+				    pkts, rcv_packet_idx);
+		netdev->stats.tx_dropped += pkts;
+		return 0;
+	}
+
+	if (priv->tx_tail != rcv_packet_idx) {
+		if (es58x_can_get_echo_skb_recovery(netdev, rcv_packet_idx) < 0) {
+			if (net_ratelimit())
+				netdev_warn(netdev,
+					    "Could not find echo skb for echo packet index: %u\n",
+					    rcv_packet_idx);
+			return 0;
+		}
+	}
+	if (num_echo_skb < pkts) {
+		int pkts_drop = pkts - num_echo_skb;
+
+		if (net_ratelimit())
+			netdev_err(netdev,
+				   "Received %u echo packets but have only %d echo skb. Dropping %d echo skb\n",
+				   pkts, num_echo_skb, pkts_drop);
+		netdev->stats.tx_dropped += pkts_drop;
+		pkts -= pkts_drop;
+	}
+
+	for (i = 0; i < pkts; i++) {
+		unsigned int skb_idx = priv->tx_tail & fifo_mask;
+		struct sk_buff *skb = priv->can.echo_skb[skb_idx];
+		unsigned int frame_len = 0;
+
+		if (skb)
+			es58x_set_skb_timestamp(netdev, skb, tstamps[i]);
+
+		netdev->stats.tx_bytes += can_get_echo_skb(netdev, skb_idx,
+							   &frame_len);
+		rx_total_frame_len += frame_len;
+
+		priv->tx_tail++;
+	}
+
+	netdev_completed_queue(netdev, pkts, rx_total_frame_len);
+	netdev->stats.tx_packets += pkts;
+
+	priv->err_passive_before_rtx_success = 0;
+	if (!es58x_is_echo_skb_threshold_reached(priv))
+		netif_wake_queue(netdev);
+
+	return 0;
+}
+
+/**
+ * es58x_can_reset_echo_fifo() - Reset the echo FIFO.
+ * @netdev: CAN network device.
+ *
+ * The echo_skb array of struct can_priv will be flushed by
+ * drivers/net/can/dev.c:can_flush_echo_skb(). This function resets
+ * the parameters of the struct es58x_priv of our device and reset the
+ * queue (c.f. BQL).
+ */
+static void es58x_can_reset_echo_fifo(struct net_device *netdev)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+
+	priv->tx_tail = 0;
+	priv->tx_head = 0;
+	priv->tx_urb = NULL;
+	priv->err_passive_before_rtx_success = 0;
+	netdev_reset_queue(netdev);
+}
+
+/**
+ * es58x_flush_pending_tx_msg() - Reset the buffer for transmission messages.
+ * @netdev: CAN network device.
+ *
+ * es58x_start_xmit() will queue up to tx_bulk_max messages in
+ * &tx_urb buffer and do a bulk send of all messages in one single URB
+ * (c.f. xmit_more flag). When the device recovers from a bus off
+ * state or when the device stops, the tx_urb buffer might still have
+ * pending messages in it and thus need to be flushed.
+ */
+static void es58x_flush_pending_tx_msg(struct net_device *netdev)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	struct es58x_device *es58x_dev = priv->es58x_dev;
+
+	if (priv->tx_urb) {
+		netdev_warn(netdev, "%s: dropping %d TX messages\n",
+			    __func__, priv->tx_can_msg_cnt);
+		netdev->stats.tx_dropped += priv->tx_can_msg_cnt;
+		while (priv->tx_can_msg_cnt > 0) {
+			unsigned int frame_len = 0;
+			u16 fifo_mask = priv->es58x_dev->param->fifo_mask;
+
+			priv->tx_head--;
+			priv->tx_can_msg_cnt--;
+			can_free_echo_skb(netdev, priv->tx_head & fifo_mask,
+					  &frame_len);
+			netdev_completed_queue(netdev, 1, frame_len);
+		}
+		usb_anchor_urb(priv->tx_urb, &priv->es58x_dev->tx_urbs_idle);
+		atomic_inc(&es58x_dev->tx_urbs_idle_cnt);
+		usb_free_urb(priv->tx_urb);
+	}
+	priv->tx_urb = NULL;
+}
+
+/**
+ * es58x_tx_ack_msg() - Handle acknowledgment messages.
+ * @netdev: CAN network device.
+ * @tx_free_entries: Number of free entries in the device transmit FIFO.
+ * @rx_cmd_ret_u32: error code as returned by the ES58X device.
+ *
+ * ES58X sends an acknowledgment message after a transmission request
+ * is done. This is mandatory for the ES581.4 but is optional (and
+ * deactivated in this driver) for the ES58X_FD family.
+ *
+ * Under normal circumstances, this function should never throw an
+ * error message.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+int es58x_tx_ack_msg(struct net_device *netdev, u16 tx_free_entries,
+		     enum es58x_ret_u32 rx_cmd_ret_u32)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+
+	if (tx_free_entries <= priv->es58x_dev->param->tx_bulk_max) {
+		if (net_ratelimit())
+			netdev_err(netdev,
+				   "Only %d entries left in device queue, num_echo_skb: %d/%d\n",
+				   tx_free_entries,
+				   priv->tx_head - priv->tx_tail,
+				   priv->can.echo_skb_max);
+		netif_stop_queue(netdev);
+	}
+
+	return es58x_rx_cmd_ret_u32(netdev, ES58X_RET_TYPE_TX_MSG,
+				    rx_cmd_ret_u32);
+}
+
+/**
+ * es58x_rx_can_msg() - Handle a received a CAN message.
+ * @netdev: CAN network device.
+ * @timestamp: Hardware time stamp (only relevant in rx branches).
+ * @data: CAN payload.
+ * @can_id: CAN ID.
+ * @es58x_flags: Please refer to enum es58x_flag.
+ * @dlc: Data Length Code (raw value).
+ *
+ * Fill up a CAN skb and post it.
+ *
+ * This function handles the case where the DLC of a classical CAN
+ * frame is greater than CAN_MAX_DLEN (c.f. the len8_dlc field of
+ * struct can_frame).
+ *
+ * Return: zero on success.
+ */
+int es58x_rx_can_msg(struct net_device *netdev, u64 timestamp, const u8 *data,
+		     canid_t can_id, enum es58x_flag es58x_flags, u8 dlc)
+{
+	struct canfd_frame *cfd;
+	struct can_frame *ccf;
+	struct sk_buff *skb;
+	u8 len;
+	bool is_can_fd = !!(es58x_flags & ES58X_FLAG_FD_DATA);
+
+	if (dlc > CAN_MAX_RAW_DLC) {
+		netdev_err(netdev,
+			   "%s: DLC is %d but maximum should be %d\n",
+			   __func__, dlc, CAN_MAX_RAW_DLC);
+		return -EMSGSIZE;
+	}
+
+	if (is_can_fd) {
+		len = can_fd_dlc2len(dlc);
+		skb = alloc_canfd_skb(netdev, &cfd);
+	} else {
+		len = can_cc_dlc2len(dlc);
+		skb = alloc_can_skb(netdev, &ccf);
+		cfd = (struct canfd_frame *)ccf;
+	}
+	if (!skb) {
+		netdev->stats.rx_dropped++;
+		return 0;
+	}
+
+	cfd->can_id = can_id;
+	if (es58x_flags & ES58X_FLAG_EFF)
+		cfd->can_id |= CAN_EFF_FLAG;
+	if (is_can_fd) {
+		cfd->len = len;
+		if (es58x_flags & ES58X_FLAG_FD_BRS)
+			cfd->flags |= CANFD_BRS;
+		if (es58x_flags & ES58X_FLAG_FD_ESI)
+			cfd->flags |= CANFD_ESI;
+	} else {
+		can_frame_set_cc_len(ccf, dlc, es58x_priv(netdev)->can.ctrlmode);
+		if (es58x_flags & ES58X_FLAG_RTR) {
+			ccf->can_id |= CAN_RTR_FLAG;
+			len = 0;
+		}
+	}
+	memcpy(cfd->data, data, len);
+	netdev->stats.rx_packets++;
+	netdev->stats.rx_bytes += len;
+
+	es58x_set_skb_timestamp(netdev, skb, timestamp);
+	netif_rx(skb);
+
+	es58x_priv(netdev)->err_passive_before_rtx_success = 0;
+
+	return 0;
+}
+
+/**
+ * es58x_rx_err_msg() - Handle a received CAN event or error message.
+ * @netdev: CAN network device.
+ * @error: Error code.
+ * @event: Event code.
+ * @timestamp: Timestamp received from a ES58X device.
+ *
+ * Handle the errors and events received by the ES58X device, create
+ * a CAN error skb and post it.
+ *
+ * In some rare cases the devices might get stuck alternating between
+ * CAN_STATE_ERROR_PASSIVE and CAN_STATE_ERROR_WARNING. To prevent
+ * this behavior, we force a bus off state if the device goes in
+ * CAN_STATE_ERROR_WARNING for ES58X_MAX_CONSECUTIVE_WARN consecutive
+ * times with no successful transmission or reception in between.
+ *
+ * Once the device is in bus off state, the only way to restart it is
+ * through the drivers/net/can/dev.c:can_restart() function. The
+ * device is technically capable to recover by itself under certain
+ * circumstances, however, allowing self recovery would create
+ * complex race conditions with drivers/net/can/dev.c:can_restart()
+ * and thus was not implemented. To activate automatic restart, please
+ * set the restart-ms parameter (e.g. ip link set can0 type can
+ * restart-ms 100).
+ *
+ * If the bus is really instable, this function would try to send a
+ * lot of log messages. Those are rate limited (i.e. you will see
+ * messages such as "net_ratelimit: XXX callbacks suppressed" in
+ * dmesg).
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+int es58x_rx_err_msg(struct net_device *netdev, enum es58x_err error,
+		     enum es58x_event event, u64 timestamp)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	struct can_priv *can = netdev_priv(netdev);
+	struct can_device_stats *can_stats = &can->can_stats;
+	struct can_frame *cf = NULL;
+	struct sk_buff *skb;
+	int ret;
+
+	if (!netif_running(netdev)) {
+		if (net_ratelimit())
+			netdev_info(netdev, "%s: %s is down, dropping packet\n",
+				    __func__, netdev->name);
+		netdev->stats.rx_dropped++;
+		return 0;
+	}
+
+	if (error == ES58X_ERR_OK && event == ES58X_EVENT_OK) {
+		netdev_err(netdev, "%s: Both error and event are zero\n",
+			   __func__);
+		return -EINVAL;
+	}
+
+	skb = alloc_can_err_skb(netdev, &cf);
+
+	switch (error) {
+	case ES58X_ERR_OK:	/* 0: No error */
+		break;
+
+	case ES58X_ERR_PROT_STUFF:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Error BITSUFF\n");
+		if (cf)
+			cf->data[2] |= CAN_ERR_PROT_STUFF;
+		break;
+
+	case ES58X_ERR_PROT_FORM:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Error FORMAT\n");
+		if (cf)
+			cf->data[2] |= CAN_ERR_PROT_FORM;
+		break;
+
+	case ES58X_ERR_ACK:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Error ACK\n");
+		if (cf)
+			cf->can_id |= CAN_ERR_ACK;
+		break;
+
+	case ES58X_ERR_PROT_BIT:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Error BIT\n");
+		if (cf)
+			cf->data[2] |= CAN_ERR_PROT_BIT;
+		break;
+
+	case ES58X_ERR_PROT_CRC:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Error CRC\n");
+		if (cf)
+			cf->data[3] |= CAN_ERR_PROT_LOC_CRC_SEQ;
+		break;
+
+	case ES58X_ERR_PROT_BIT1:
+		if (net_ratelimit())
+			netdev_dbg(netdev,
+				   "Error: expected a recessive bit but monitored a dominant one\n");
+		if (cf)
+			cf->data[2] |= CAN_ERR_PROT_BIT1;
+		break;
+
+	case ES58X_ERR_PROT_BIT0:
+		if (net_ratelimit())
+			netdev_dbg(netdev,
+				   "Error expected a dominant bit but monitored a recessive one\n");
+		if (cf)
+			cf->data[2] |= CAN_ERR_PROT_BIT0;
+		break;
+
+	case ES58X_ERR_PROT_OVERLOAD:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Error OVERLOAD\n");
+		if (cf)
+			cf->data[2] |= CAN_ERR_PROT_OVERLOAD;
+		break;
+
+	case ES58X_ERR_PROT_UNSPEC:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Unspecified error\n");
+		if (cf)
+			cf->can_id |= CAN_ERR_PROT;
+		break;
+
+	default:
+		if (net_ratelimit())
+			netdev_err(netdev,
+				   "%s: Unspecified error code 0x%04X\n",
+				   __func__, (int)error);
+		if (cf)
+			cf->can_id |= CAN_ERR_PROT;
+		break;
+	}
+
+	switch (event) {
+	case ES58X_EVENT_OK:	/* 0: No event */
+		break;
+
+	case ES58X_EVENT_CRTL_ACTIVE:
+		if (can->state == CAN_STATE_BUS_OFF) {
+			netdev_err(netdev,
+				   "%s: state transition: BUS OFF -> ACTIVE\n",
+				   __func__);
+		}
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Event CAN BUS ACTIVE\n");
+		if (cf)
+			cf->data[1] |= CAN_ERR_CRTL_ACTIVE;
+		can->state = CAN_STATE_ERROR_ACTIVE;
+		break;
+
+	case ES58X_EVENT_CRTL_PASSIVE:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Event CAN BUS PASSIVE\n");
+		/* Either TX or RX error count reached passive state
+		 * but we do not know which. Setting both flags by
+		 * default.
+		 */
+		if (cf) {
+			cf->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
+			cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE;
+		}
+		if (can->state < CAN_STATE_BUS_OFF)
+			can->state = CAN_STATE_ERROR_PASSIVE;
+		can_stats->error_passive++;
+		if (priv->err_passive_before_rtx_success < U8_MAX)
+			priv->err_passive_before_rtx_success++;
+		break;
+
+	case ES58X_EVENT_CRTL_WARNING:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Event CAN BUS WARNING\n");
+		/* Either TX or RX error count reached warning state
+		 * but we do not know which. Setting both flags by
+		 * default.
+		 */
+		if (cf) {
+			cf->data[1] |= CAN_ERR_CRTL_RX_WARNING;
+			cf->data[1] |= CAN_ERR_CRTL_TX_WARNING;
+		}
+		if (can->state < CAN_STATE_BUS_OFF)
+			can->state = CAN_STATE_ERROR_WARNING;
+		can_stats->error_warning++;
+		break;
+
+	case ES58X_EVENT_BUSOFF:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Event CAN BUS OFF\n");
+		if (cf)
+			cf->can_id |= CAN_ERR_BUSOFF;
+		can_stats->bus_off++;
+		netif_stop_queue(netdev);
+		if (can->state != CAN_STATE_BUS_OFF) {
+			can->state = CAN_STATE_BUS_OFF;
+			can_bus_off(netdev);
+			ret = can->do_set_mode(netdev, CAN_MODE_STOP);
+			if (ret)
+				return ret;
+		}
+		break;
+
+	case ES58X_EVENT_SINGLE_WIRE:
+		if (net_ratelimit())
+			netdev_warn(netdev,
+				    "Lost connection on either CAN high or CAN low\n");
+		/* Lost connection on either CAN high or CAN
+		 * low. Setting both flags by default.
+		 */
+		if (cf) {
+			cf->data[4] |= CAN_ERR_TRX_CANH_NO_WIRE;
+			cf->data[4] |= CAN_ERR_TRX_CANL_NO_WIRE;
+		}
+		break;
+
+	default:
+		if (net_ratelimit())
+			netdev_err(netdev,
+				   "%s: Unspecified event code 0x%04X\n",
+				   __func__, (int)event);
+		if (cf)
+			cf->can_id |= CAN_ERR_CRTL;
+		break;
+	}
+
+	/* driver/net/can/dev.c:can_restart() takes in account error
+	 * messages in the RX stats. Doing the same here for
+	 * consistency.
+	 */
+	netdev->stats.rx_packets++;
+	netdev->stats.rx_bytes += cf->can_dlc;
+
+	if (cf) {
+		if (cf->data[1])
+			cf->can_id |= CAN_ERR_CRTL;
+		if (cf->data[2] || cf->data[3]) {
+			cf->can_id |= CAN_ERR_PROT;
+			can_stats->bus_error++;
+		}
+		if (cf->data[4])
+			cf->can_id |= CAN_ERR_TRX;
+
+		es58x_set_skb_timestamp(netdev, skb, timestamp);
+		netif_rx(skb);
+	}
+
+	if ((event & ES58X_EVENT_CRTL_PASSIVE) &&
+	    priv->err_passive_before_rtx_success == ES58X_CONSECUTIVE_ERR_PASSIVE_MAX) {
+		netdev_info(netdev,
+			    "Got %d consecutive warning events with no successful RX or TX. Forcing bus-off\n",
+			    priv->err_passive_before_rtx_success);
+		return es58x_rx_err_msg(netdev, ES58X_ERR_OK,
+					ES58X_EVENT_BUSOFF, timestamp);
+	}
+
+	return 0;
+}
+
+/**
+ * es58x_cmd_ret_desc() - Convert a command type to a string.
+ * @cmd_ret_type: Type of the command which triggered the return code.
+ *
+ * The final line (return "<unknown>") should not be reached. If this
+ * is the case, there is an implementation bug.
+ *
+ * Return: a readable description of the @cmd_ret_type.
+ */
+static const char *es58x_cmd_ret_desc(enum es58x_ret_type cmd_ret_type)
+{
+	switch (cmd_ret_type) {
+	case ES58X_RET_TYPE_SET_BITTIMING:
+		return "Set bittiming";
+	case ES58X_RET_TYPE_ENABLE_CHANNEL:
+		return "Enable channel";
+	case ES58X_RET_TYPE_DISABLE_CHANNEL:
+		return "Disable channel";
+	case ES58X_RET_TYPE_TX_MSG:
+		return "Transmit message";
+	case ES58X_RET_TYPE_RESET_RX:
+		return "Reset RX";
+	case ES58X_RET_TYPE_RESET_TX:
+		return "Reset TX";
+	case ES58X_RET_TYPE_DEVICE_ERR:
+		return "Device error";
+	}
+
+	return "<unknown>";
+};
+
+/**
+ * es58x_rx_cmd_ret_u8() - Handle the command's return code received
+ *	from the ES58X device.
+ * @dev: Device, only used for the dev_XXX() print functions.
+ * @cmd_ret_type: Type of the command which triggered the return code.
+ * @rx_cmd_ret_u8: Command error code as returned by the ES58X device.
+ *
+ * Handles the 8 bits command return code. Those are specific to the
+ * ES581.4 device. The return value will eventually be used by
+ * es58x_handle_urb_cmd() function which will take proper actions in
+ * case of critical issues such and memory errors or bad CRC values.
+ *
+ * In contrast with es58x_rx_cmd_ret_u32(), the network device is
+ * unknown.
+ *
+ * Return: zero on success, return errno when any error occurs.
+ */
+int es58x_rx_cmd_ret_u8(struct device *dev,
+			enum es58x_ret_type cmd_ret_type,
+			enum es58x_ret_u8 rx_cmd_ret_u8)
+{
+	const char *ret_desc = es58x_cmd_ret_desc(cmd_ret_type);
+
+	switch (rx_cmd_ret_u8) {
+	case ES58X_RET_U8_OK:
+		dev_dbg_ratelimited(dev, "%s: OK\n", ret_desc);
+		return 0;
+
+	case ES58X_RET_U8_ERR_UNSPECIFIED_FAILURE:
+		dev_err(dev, "%s: unspecified failure\n", ret_desc);
+		return -EBADMSG;
+
+	case ES58X_RET_U8_ERR_NO_MEM:
+		dev_err(dev, "%s: device ran out of memory\n", ret_desc);
+		return -ENOMEM;
+
+	case ES58X_RET_U8_ERR_BAD_CRC:
+		dev_err(dev, "%s: CRC of previous command is incorrect\n",
+			ret_desc);
+		return -EIO;
+
+	default:
+		dev_err(dev, "%s: returned unknown value: 0x%02X\n",
+			ret_desc, rx_cmd_ret_u8);
+		return -EBADMSG;
+	}
+}
+
+/**
+ * es58x_rx_cmd_ret_u32() - Handle the command return code received
+ *	from the ES58X device.
+ * @netdev: CAN network device.
+ * @cmd_ret_type: Type of the command which triggered the return code.
+ * @rx_cmd_ret_u32: error code as returned by the ES58X device.
+ *
+ * Handles the 32 bits command return code. The return value will
+ * eventually be used by es58x_handle_urb_cmd() function which will
+ * take proper actions in case of critical issues such and memory
+ * errors or bad CRC values.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+int es58x_rx_cmd_ret_u32(struct net_device *netdev,
+			 enum es58x_ret_type cmd_ret_type,
+			 enum es58x_ret_u32 rx_cmd_ret_u32)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	const struct es58x_operators *ops = priv->es58x_dev->ops;
+	const char *ret_desc = es58x_cmd_ret_desc(cmd_ret_type);
+
+	switch (rx_cmd_ret_u32) {
+	case ES58X_RET_U32_OK:
+		switch (cmd_ret_type) {
+		case ES58X_RET_TYPE_ENABLE_CHANNEL:
+			es58x_can_reset_echo_fifo(netdev);
+			priv->can.state = CAN_STATE_ERROR_ACTIVE;
+			netif_wake_queue(netdev);
+			netdev_info(netdev,
+				    "%s: %s (Serial Number %s): CAN%d channel becomes ready\n",
+				    ret_desc, priv->es58x_dev->udev->product,
+				    priv->es58x_dev->udev->serial,
+				    priv->channel_idx + 1);
+			break;
+
+		case ES58X_RET_TYPE_TX_MSG:
+			if (IS_ENABLED(CONFIG_VERBOSE_DEBUG) && net_ratelimit())
+				netdev_vdbg(netdev, "%s: OK\n", ret_desc);
+			break;
+
+		default:
+			netdev_dbg(netdev, "%s: OK\n", ret_desc);
+			break;
+		}
+		return 0;
+
+	case ES58X_RET_U32_ERR_UNSPECIFIED_FAILURE:
+		if (cmd_ret_type == ES58X_RET_TYPE_ENABLE_CHANNEL) {
+			int ret;
+
+			netdev_warn(netdev,
+				    "%s: channel is already opened, closing and re-openning it to reflect new configuration\n",
+				    ret_desc);
+			ret = ops->disable_channel(es58x_priv(netdev));
+			if (ret)
+				return ret;
+			return ops->enable_channel(es58x_priv(netdev));
+		}
+		if (cmd_ret_type == ES58X_RET_TYPE_DISABLE_CHANNEL) {
+			netdev_info(netdev,
+				    "%s: channel is already closed\n", ret_desc);
+			return 0;
+		}
+		netdev_err(netdev,
+			   "%s: unspecified failure\n", ret_desc);
+		return -EBADMSG;
+
+	case ES58X_RET_U32_ERR_NO_MEM:
+		netdev_err(netdev, "%s: device ran out of memory\n", ret_desc);
+		return -ENOMEM;
+
+	case ES58X_RET_U32_WARN_PARAM_ADJUSTED:
+		netdev_warn(netdev,
+			    "%s: some incompatible parameters have been adjusted\n",
+			    ret_desc);
+		return 0;
+
+	case ES58X_RET_U32_WARN_TX_MAYBE_REORDER:
+		netdev_warn(netdev,
+			    "%s: TX messages might have been reordered\n",
+			    ret_desc);
+		return 0;
+
+	case ES58X_RET_U32_ERR_TIMEDOUT:
+		netdev_err(netdev, "%s: command timed out\n", ret_desc);
+		return -ETIMEDOUT;
+
+	case ES58X_RET_U32_ERR_FIFO_FULL:
+		netdev_warn(netdev, "%s: fifo is full\n", ret_desc);
+		return 0;
+
+	case ES58X_RET_U32_ERR_BAD_CONFIG:
+		netdev_err(netdev, "%s: bad configuration\n", ret_desc);
+		return -EINVAL;
+
+	case ES58X_RET_U32_ERR_NO_RESOURCE:
+		netdev_err(netdev, "%s: no resource available\n", ret_desc);
+		return -EBUSY;
+
+	default:
+		netdev_err(netdev, "%s returned unknown value: 0x%08X\n",
+			   ret_desc, rx_cmd_ret_u32);
+		return -EBADMSG;
+	}
+}
+
+/**
+ * es58x_increment_rx_errors() - Increment the network devices' error
+ *	count.
+ * @es58x_dev: ES58X device.
+ *
+ * If an error occurs on the early stages on receiving an URB command,
+ * we might not be able to figure out on which network device the
+ * error occurred. In such case, we arbitrarily increment the error
+ * count of all the network devices attached to our ES58X device.
+ */
+static void es58x_increment_rx_errors(struct es58x_device *es58x_dev)
+{
+	int i;
+
+	for (i = 0; i < es58x_dev->num_can_ch; i++)
+		if (es58x_dev->netdev[i])
+			es58x_dev->netdev[i]->stats.rx_errors++;
+}
+
+/**
+ * es58x_handle_urb_cmd() - Handle the URB command
+ * @es58x_dev: ES58X device.
+ * @urb_cmd: The URB command received from the ES58X device, might not
+ *	be aligned.
+ *
+ * Sends the URB command to the device specific function. Manages the
+ * errors thrown back by those functions.
+ */
+static void es58x_handle_urb_cmd(struct es58x_device *es58x_dev,
+				 const union es58x_urb_cmd *urb_cmd)
+{
+	const struct es58x_operators *ops = es58x_dev->ops;
+	size_t cmd_len;
+	int i, ret;
+
+	ret = ops->handle_urb_cmd(es58x_dev, urb_cmd);
+	switch (ret) {
+	case 0:		/* OK */
+		return;
+
+	case -ENODEV:
+		dev_err_ratelimited(es58x_dev->dev, "Device is not ready\n");
+		break;
+
+	case -EINVAL:
+	case -EMSGSIZE:
+	case -EBADRQC:
+	case -EBADMSG:
+	case -ECHRNG:
+	case -ETIMEDOUT:
+		cmd_len = es58x_get_urb_cmd_len(es58x_dev,
+						ops->get_msg_len(urb_cmd));
+		dev_err(es58x_dev->dev,
+			"ops->handle_urb_cmd() returned error %pe",
+			ERR_PTR(ret));
+		es58x_print_hex_dump(urb_cmd, cmd_len);
+		break;
+
+	case -EFAULT:
+	case -ENOMEM:
+	case -EIO:
+	default:
+		dev_crit(es58x_dev->dev,
+			 "ops->handle_urb_cmd() returned error %pe, detaching all network devices\n",
+			 ERR_PTR(ret));
+		for (i = 0; i < es58x_dev->num_can_ch; i++)
+			if (es58x_dev->netdev[i])
+				netif_device_detach(es58x_dev->netdev[i]);
+		if (es58x_dev->ops->reset_device)
+			es58x_dev->ops->reset_device(es58x_dev);
+		break;
+	}
+
+	/* Because the urb command could not fully be parsed,
+	 * channel_id is not confirmed. Incrementing rx_errors count
+	 * of all channels.
+	 */
+	es58x_increment_rx_errors(es58x_dev);
+}
+
+/**
+ * es58x_check_rx_urb() - Check the length and format of the URB command.
+ * @es58x_dev: ES58X device.
+ * @urb_cmd: The URB command received from the ES58X device, might not
+ *	be aligned.
+ * @urb_actual_len: The actual length of the URB command.
+ *
+ * Check if the first message of the received urb is valid, that is to
+ * say that both the header and the length are coherent.
+ *
+ * Return:
+ * the length of the first message of the URB on success.
+ *
+ * -ENODATA if the URB command is incomplete (in which case, the URB
+ * command should be buffered and combined with the next URB to try to
+ * reconstitute the URB command).
+ *
+ * -EOVERFLOW if the length is bigger than the maximum expected one.
+ *
+ * -EBADRQC if the start of frame does not match the expected value.
+ */
+static signed int es58x_check_rx_urb(struct es58x_device *es58x_dev,
+				     const union es58x_urb_cmd *urb_cmd,
+				     u32 urb_actual_len)
+{
+	const struct device *dev = es58x_dev->dev;
+	const struct es58x_parameters *param = es58x_dev->param;
+	u16 sof, msg_len;
+	signed int urb_cmd_len, ret;
+
+	if (urb_actual_len < param->urb_cmd_header_len) {
+		dev_vdbg(dev,
+			 "%s: Received %d bytes [%*ph]: header incomplete\n",
+			 __func__, urb_actual_len, urb_actual_len,
+			 urb_cmd->raw_cmd);
+		return -ENODATA;
+	}
+
+	sof = get_unaligned_le16(&urb_cmd->sof);
+	if (sof != param->rx_start_of_frame) {
+		dev_err_ratelimited(es58x_dev->dev,
+				    "%s: Expected sequence 0x%04X for start of frame but got 0x%04X.\n",
+				    __func__, param->rx_start_of_frame, sof);
+		return -EBADRQC;
+	}
+
+	msg_len = es58x_dev->ops->get_msg_len(urb_cmd);
+	urb_cmd_len = es58x_get_urb_cmd_len(es58x_dev, msg_len);
+	if (urb_cmd_len > param->rx_urb_cmd_max_len) {
+		dev_err_ratelimited(es58x_dev->dev,
+				    "%s: Biggest expected size for rx urb_cmd is %u but receive a command of size %d\n",
+				    __func__,
+				    param->rx_urb_cmd_max_len, urb_cmd_len);
+		return -EOVERFLOW;
+	} else if (urb_actual_len < urb_cmd_len) {
+		dev_vdbg(dev, "%s: Received %02d/%02d bytes\n",
+			 __func__, urb_actual_len, urb_cmd_len);
+		return -ENODATA;
+	}
+
+	ret = es58x_check_crc(es58x_dev, urb_cmd, urb_cmd_len);
+	if (ret)
+		return ret;
+
+	return urb_cmd_len;
+}
+
+/**
+ * es58x_copy_to_cmd_buf() - Copy an array to the URB command buffer.
+ * @es58x_dev: ES58X device.
+ * @raw_cmd: the buffer we want to copy.
+ * @raw_cmd_len: length of @raw_cmd.
+ *
+ * Concatenates @raw_cmd_len bytes of @raw_cmd to the end of the URB
+ * command buffer.
+ *
+ * Return: zero on success, -EMSGSIZE if not enough space is available
+ * to do the copy.
+ */
+static int es58x_copy_to_cmd_buf(struct es58x_device *es58x_dev,
+				 u8 *raw_cmd, int raw_cmd_len)
+{
+	if (es58x_dev->rx_cmd_buf_len + raw_cmd_len >
+	    es58x_dev->param->rx_urb_cmd_max_len)
+		return -EMSGSIZE;
+
+	memcpy(&es58x_dev->rx_cmd_buf.raw_cmd[es58x_dev->rx_cmd_buf_len],
+	       raw_cmd, raw_cmd_len);
+	es58x_dev->rx_cmd_buf_len += raw_cmd_len;
+
+	return 0;
+}
+
+/**
+ * es58x_split_urb_try_recovery() - Try to recover bad URB sequences.
+ * @es58x_dev: ES58X device.
+ * @raw_cmd: pointer to the buffer we want to copy.
+ * @raw_cmd_len: length of @raw_cmd.
+ *
+ * Under some rare conditions, we might get incorrect URBs from the
+ * device. From our observations, one of the valid URB gets replaced
+ * by one from the past. The full root cause is not identified.
+ *
+ * This function looks for the next start of frame in the urb buffer
+ * in order to try to recover.
+ *
+ * Such behavior was not observed on the devices of the ES58X FD
+ * family and only seems to impact the ES581.4.
+ *
+ * Return: the number of bytes dropped on success, -EBADMSG if recovery failed.
+ */
+static int es58x_split_urb_try_recovery(struct es58x_device *es58x_dev,
+					u8 *raw_cmd, size_t raw_cmd_len)
+{
+	union es58x_urb_cmd *urb_cmd;
+	signed int urb_cmd_len;
+	u16 sof;
+	int dropped_bytes = 0;
+
+	es58x_increment_rx_errors(es58x_dev);
+
+	while (raw_cmd_len > sizeof(sof)) {
+		urb_cmd = (union es58x_urb_cmd *)raw_cmd;
+		sof = get_unaligned_le16(&urb_cmd->sof);
+
+		if (sof == es58x_dev->param->rx_start_of_frame) {
+			urb_cmd_len = es58x_check_rx_urb(es58x_dev,
+							 urb_cmd, raw_cmd_len);
+			if ((urb_cmd_len == -ENODATA) || urb_cmd_len > 0) {
+				dev_info_ratelimited(es58x_dev->dev,
+						     "Recovery successful! Dropped %d bytes (urb_cmd_len: %d)\n",
+						     dropped_bytes,
+						     urb_cmd_len);
+				return dropped_bytes;
+			}
+		}
+		raw_cmd++;
+		raw_cmd_len--;
+		dropped_bytes++;
+	}
+
+	dev_warn_ratelimited(es58x_dev->dev, "%s: Recovery failed\n", __func__);
+	return -EBADMSG;
+}
+
+/**
+ * es58x_handle_incomplete_cmd() - Reconstitute an URB command from
+ *	different URB pieces.
+ * @es58x_dev: ES58X device.
+ * @urb: last urb buffer received.
+ *
+ * The device might split the URB commands in an arbitrary amount of
+ * pieces. This function concatenates those in an URB buffer until a
+ * full URB command is reconstituted and consume it.
+ *
+ * Return:
+ * number of bytes consumed from @urb if successful.
+ *
+ * -ENODATA if the URB command is still incomplete.
+ *
+ * -EBADMSG if the URB command is incorrect.
+ */
+static signed int es58x_handle_incomplete_cmd(struct es58x_device *es58x_dev,
+					      struct urb *urb)
+{
+	size_t cpy_len;
+	signed int urb_cmd_len, tmp_cmd_buf_len, ret;
+
+	tmp_cmd_buf_len = es58x_dev->rx_cmd_buf_len;
+	cpy_len = min_t(int, es58x_dev->param->rx_urb_cmd_max_len -
+			es58x_dev->rx_cmd_buf_len, urb->actual_length);
+	ret = es58x_copy_to_cmd_buf(es58x_dev, urb->transfer_buffer, cpy_len);
+	if (ret < 0)
+		return ret;
+
+	urb_cmd_len = es58x_check_rx_urb(es58x_dev, &es58x_dev->rx_cmd_buf,
+					 es58x_dev->rx_cmd_buf_len);
+	if (urb_cmd_len == -ENODATA) {
+		return -ENODATA;
+	} else if (urb_cmd_len < 0) {
+		dev_err_ratelimited(es58x_dev->dev,
+				    "Could not reconstitute incomplete command from previous URB, dropping %d bytes\n",
+				    tmp_cmd_buf_len + urb->actual_length);
+		dev_err_ratelimited(es58x_dev->dev,
+				    "Error code: %pe, es58x_dev->rx_cmd_buf_len: %d, urb->actual_length: %u\n",
+				    ERR_PTR(urb_cmd_len),
+				    tmp_cmd_buf_len, urb->actual_length);
+		es58x_print_hex_dump(&es58x_dev->rx_cmd_buf, tmp_cmd_buf_len);
+		es58x_print_hex_dump(urb->transfer_buffer, urb->actual_length);
+		return urb->actual_length;
+	}
+
+	es58x_handle_urb_cmd(es58x_dev, &es58x_dev->rx_cmd_buf);
+	return urb_cmd_len - tmp_cmd_buf_len;	/* consumed length */
+}
+
+/**
+ * es58x_split_urb() - Cut the received URB in individual URB commands.
+ * @es58x_dev: ES58X device.
+ * @urb: last urb buffer received.
+ *
+ * The device might send urb in bulk format (i.e. several URB commands
+ * concatenated together). This function will split all the commands
+ * contained in the urb.
+ *
+ * Return:
+ * number of bytes consumed from @urb if successful.
+ *
+ * -ENODATA if the URB command is incomplete.
+ *
+ * -EBADMSG if the URB command is incorrect.
+ */
+static signed int es58x_split_urb(struct es58x_device *es58x_dev,
+				  struct urb *urb)
+{
+	union es58x_urb_cmd *urb_cmd;
+	u8 *raw_cmd = urb->transfer_buffer;
+	s32 raw_cmd_len = urb->actual_length;
+	int ret;
+
+	if (es58x_dev->rx_cmd_buf_len != 0) {
+		ret = es58x_handle_incomplete_cmd(es58x_dev, urb);
+		if (ret != -ENODATA)
+			es58x_dev->rx_cmd_buf_len = 0;
+		if (ret < 0)
+			return ret;
+
+		raw_cmd += ret;
+		raw_cmd_len -= ret;
+	}
+
+	while (raw_cmd_len > 0) {
+		if (raw_cmd[0] == ES58X_HEARTBEAT) {
+			raw_cmd++;
+			raw_cmd_len--;
+			continue;
+		}
+		urb_cmd = (union es58x_urb_cmd *)raw_cmd;
+		ret = es58x_check_rx_urb(es58x_dev, urb_cmd, raw_cmd_len);
+		if (ret > 0) {
+			es58x_handle_urb_cmd(es58x_dev, urb_cmd);
+		} else if (ret == -ENODATA) {
+			es58x_copy_to_cmd_buf(es58x_dev, raw_cmd, raw_cmd_len);
+			return -ENODATA;
+		} else if (ret < 0) {
+			ret = es58x_split_urb_try_recovery(es58x_dev, raw_cmd,
+							   raw_cmd_len);
+			if (ret < 0)
+				return ret;
+		}
+		raw_cmd += ret;
+		raw_cmd_len -= ret;
+	}
+
+	return 0;
+}
+
+/**
+ * es58x_read_bulk_callback() - Callback for reading data from device.
+ * @urb: last urb buffer received.
+ *
+ * This function gets eventually called each time an URB is received
+ * from the ES58X device.
+ *
+ * Checks urb status, calls read function and resubmits urb read
+ * operation.
+ */
+static void es58x_read_bulk_callback(struct urb *urb)
+{
+	struct es58x_device *es58x_dev = urb->context;
+	const struct device *dev = es58x_dev->dev;
+	int i, ret;
+
+	switch (urb->status) {
+	case 0:		/* success */
+		break;
+
+	case -EOVERFLOW:
+		dev_err_ratelimited(dev, "%s: error %pe\n",
+				    __func__, ERR_PTR(urb->status));
+		es58x_print_hex_dump_debug(urb->transfer_buffer,
+					   urb->transfer_buffer_length);
+		goto resubmit_urb;
+
+	case -EPROTO:
+		dev_warn_ratelimited(dev, "%s: error %pe. Device unplugged?\n",
+				     __func__, ERR_PTR(urb->status));
+		goto free_urb;
+
+	case -ENOENT:
+	case -EPIPE:
+		dev_err_ratelimited(dev, "%s: error %pe\n",
+				    __func__, ERR_PTR(urb->status));
+		goto free_urb;
+
+	case -ESHUTDOWN:
+		dev_dbg_ratelimited(dev, "%s: error %pe\n",
+				    __func__, ERR_PTR(urb->status));
+		goto free_urb;
+
+	default:
+		dev_err_ratelimited(dev, "%s: error %pe\n",
+				    __func__, ERR_PTR(urb->status));
+		goto resubmit_urb;
+	}
+
+	ret = es58x_split_urb(es58x_dev, urb);
+	if ((ret != -ENODATA) && ret < 0) {
+		dev_err(es58x_dev->dev, "es58x_split_urb() returned error %pe",
+			ERR_PTR(ret));
+		es58x_print_hex_dump_debug(urb->transfer_buffer,
+					   urb->actual_length);
+
+		/* Because the urb command could not be parsed,
+		 * channel_id is not confirmed. Incrementing rx_errors
+		 * count of all channels.
+		 */
+		es58x_increment_rx_errors(es58x_dev);
+	}
+
+ resubmit_urb:
+	usb_fill_bulk_urb(urb, es58x_dev->udev, es58x_dev->rx_pipe,
+			  urb->transfer_buffer, urb->transfer_buffer_length,
+			  es58x_read_bulk_callback, es58x_dev);
+
+	ret = usb_submit_urb(urb, GFP_ATOMIC);
+	if (ret == -ENODEV) {
+		for (i = 0; i < es58x_dev->num_can_ch; i++)
+			if (es58x_dev->netdev[i])
+				netif_device_detach(es58x_dev->netdev[i]);
+	} else if (ret)
+		dev_err_ratelimited(dev,
+				    "Failed resubmitting read bulk urb: %pe\n",
+				    ERR_PTR(ret));
+	return;
+
+ free_urb:
+	usb_free_coherent(urb->dev, urb->transfer_buffer_length,
+			  urb->transfer_buffer, urb->transfer_dma);
+}
+
+/**
+ * es58x_write_bulk_callback() - Callback after writing data to the device.
+ * @urb: urb buffer which was previously submitted.
+ *
+ * This function gets eventually called each time an URB was sent to
+ * the ES58X device.
+ *
+ * Puts the @urb back to the urbs idle anchor and tries to restart the
+ * network queue.
+ */
+static void es58x_write_bulk_callback(struct urb *urb)
+{
+	struct net_device *netdev = urb->context;
+	struct es58x_device *es58x_dev = es58x_priv(netdev)->es58x_dev;
+
+	switch (urb->status) {
+	case 0:		/* success */
+		break;
+
+	case -EOVERFLOW:
+		if (net_ratelimit())
+			netdev_err(netdev, "%s: error %pe\n",
+				   __func__, ERR_PTR(urb->status));
+		es58x_print_hex_dump(urb->transfer_buffer,
+				     urb->transfer_buffer_length);
+		break;
+
+	case -ENOENT:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "%s: error %pe\n",
+				   __func__, ERR_PTR(urb->status));
+		usb_free_coherent(urb->dev,
+				  es58x_dev->param->tx_urb_cmd_max_len,
+				  urb->transfer_buffer, urb->transfer_dma);
+		return;
+
+	default:
+		if (net_ratelimit())
+			netdev_info(netdev, "%s: error %pe\n",
+				    __func__, ERR_PTR(urb->status));
+		break;
+	}
+
+	usb_anchor_urb(urb, &es58x_dev->tx_urbs_idle);
+	atomic_inc(&es58x_dev->tx_urbs_idle_cnt);
+}
+
+/**
+ * es58x_alloc_urb() - Allocate memory for an URB and its transfer
+ *	buffer.
+ * @es58x_dev: ES58X device.
+ * @urb: URB to be allocated.
+ * @buf: used to return DMA address of buffer.
+ * @buf_len: requested buffer size.
+ * @mem_flags: affect whether allocation may block.
+ *
+ * Allocates an URB and its @transfer_buffer and set its @transfer_dma
+ * address.
+ *
+ * This function is used at start-up to allocate all RX URBs at once
+ * and during run time for TX URBs.
+ *
+ * Return: zero on success, -ENOMEM if no memory is available.
+ */
+static int es58x_alloc_urb(struct es58x_device *es58x_dev, struct urb **urb,
+			   u8 **buf, size_t buf_len, gfp_t mem_flags)
+{
+	*urb = usb_alloc_urb(0, mem_flags);
+	if (!*urb) {
+		dev_err(es58x_dev->dev, "No memory left for URBs\n");
+		return -ENOMEM;
+	}
+
+	*buf = usb_alloc_coherent(es58x_dev->udev, buf_len,
+				  mem_flags, &(*urb)->transfer_dma);
+	if (!*buf) {
+		dev_err(es58x_dev->dev, "No memory left for USB buffer\n");
+		usb_free_urb(*urb);
+		return -ENOMEM;
+	}
+
+	(*urb)->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+
+	return 0;
+}
+
+/**
+ * es58x_get_tx_urb() - Get an URB for transmission.
+ * @es58x_dev: ES58X device.
+ *
+ * Gets an URB from the idle urbs anchor or allocate a new one if the
+ * anchor is empty.
+ *
+ * If there are more than ES58X_TX_URBS_MAX in the idle anchor, do
+ * some garbage collection. The garbage collection is done here
+ * instead of within es58x_write_bulk_callback() because
+ * usb_free_coherent() should not be used in IRQ context:
+ * c.f. WARN_ON(irqs_disabled()) in dma_free_attrs().
+ *
+ * Return: a pointer to an URB on success, NULL if no memory is
+ * available.
+ */
+static struct urb *es58x_get_tx_urb(struct es58x_device *es58x_dev)
+{
+	atomic_t *idle_cnt = &es58x_dev->tx_urbs_idle_cnt;
+	struct urb *urb = usb_get_from_anchor(&es58x_dev->tx_urbs_idle);
+
+	if (!urb) {
+		size_t tx_buf_len;
+		u8 *buf;
+
+		tx_buf_len = es58x_dev->param->tx_urb_cmd_max_len;
+		if (es58x_alloc_urb(es58x_dev, &urb, &buf, tx_buf_len,
+				    GFP_ATOMIC))
+			return NULL;
+
+		usb_fill_bulk_urb(urb, es58x_dev->udev, es58x_dev->tx_pipe,
+				  buf, tx_buf_len, NULL, NULL);
+		return urb;
+	}
+
+	while (atomic_dec_return(idle_cnt) > ES58X_TX_URBS_MAX) {
+		/* Garbage collector */
+		struct urb *tmp = usb_get_from_anchor(&es58x_dev->tx_urbs_idle);
+
+		if (!tmp)
+			break;
+		usb_free_coherent(tmp->dev,
+				  es58x_dev->param->tx_urb_cmd_max_len,
+				  tmp->transfer_buffer, tmp->transfer_dma);
+		usb_free_urb(tmp);
+	}
+
+	return urb;
+}
+
+/**
+ * es58x_submit_urb() - Send data to the device.
+ * @es58x_dev: ES58X device.
+ * @urb: URB to be sent.
+ * @netdev: CAN network device.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_submit_urb(struct es58x_device *es58x_dev, struct urb *urb,
+			    struct net_device *netdev)
+{
+	int ret;
+
+	es58x_set_crc(urb->transfer_buffer, urb->transfer_buffer_length);
+	usb_fill_bulk_urb(urb, es58x_dev->udev, es58x_dev->tx_pipe,
+			  urb->transfer_buffer, urb->transfer_buffer_length,
+			  es58x_write_bulk_callback, netdev);
+	usb_anchor_urb(urb, &es58x_dev->tx_urbs_busy);
+	ret = usb_submit_urb(urb, GFP_ATOMIC);
+	if (ret) {
+		netdev_err(netdev, "%s: USB send urb failure: %pe\n",
+			   __func__, ERR_PTR(ret));
+		usb_unanchor_urb(urb);
+		usb_free_coherent(urb->dev,
+				  es58x_dev->param->tx_urb_cmd_max_len,
+				  urb->transfer_buffer, urb->transfer_dma);
+	}
+	usb_free_urb(urb);
+
+	return ret;
+}
+
+/**
+ * es58x_send_msg() - Prepare an URB and submit it.
+ * @es58x_dev: ES58X device.
+ * @cmd_type: Command type.
+ * @cmd_id: Command ID.
+ * @msg: ES58X message to be sent.
+ * @msg_len: Length of @msg.
+ * @channel_idx: Index of the network device.
+ *
+ * Creates an URB command from a given message, sets the header and the
+ * CRC and then submits it.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+int es58x_send_msg(struct es58x_device *es58x_dev, u8 cmd_type, u8 cmd_id,
+		   const void *msg, u16 msg_len, int channel_idx)
+{
+	struct net_device *netdev;
+	union es58x_urb_cmd *urb_cmd;
+	struct urb *urb;
+	int urb_cmd_len;
+
+	if (channel_idx == ES58X_CHANNEL_IDX_NA)
+		netdev = es58x_dev->netdev[0];	/* Default to first channel */
+	else
+		netdev = es58x_dev->netdev[channel_idx];
+
+	urb_cmd_len = es58x_get_urb_cmd_len(es58x_dev, msg_len);
+	if (urb_cmd_len > es58x_dev->param->tx_urb_cmd_max_len)
+		return -EOVERFLOW;
+
+	urb = es58x_get_tx_urb(es58x_dev);
+	if (!urb)
+		return -ENOMEM;
+
+	urb_cmd = urb->transfer_buffer;
+	es58x_dev->ops->fill_urb_header(urb_cmd, cmd_type, cmd_id,
+					channel_idx, msg_len);
+	memcpy(&urb_cmd->raw_cmd[es58x_dev->param->urb_cmd_header_len],
+	       msg, msg_len);
+	urb->transfer_buffer_length = urb_cmd_len;
+
+	return es58x_submit_urb(es58x_dev, urb, netdev);
+}
+
+/**
+ * es58x_alloc_rx_urbs() - Allocate RX URBs.
+ * @es58x_dev: ES58X device.
+ *
+ * Allocate URBs for reception and anchor them.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_alloc_rx_urbs(struct es58x_device *es58x_dev)
+{
+	const struct device *dev = es58x_dev->dev;
+	const struct es58x_parameters *param = es58x_dev->param;
+	size_t rx_buf_len = es58x_dev->rx_max_packet_size;
+	struct urb *urb;
+	u8 *buf;
+	int i;
+	int ret = -EINVAL;
+
+	for (i = 0; i < param->rx_urb_max; i++) {
+		ret = es58x_alloc_urb(es58x_dev, &urb, &buf, rx_buf_len,
+				      GFP_KERNEL);
+		if (ret)
+			break;
+
+		usb_fill_bulk_urb(urb, es58x_dev->udev, es58x_dev->rx_pipe,
+				  buf, rx_buf_len, es58x_read_bulk_callback,
+				  es58x_dev);
+		usb_anchor_urb(urb, &es58x_dev->rx_urbs);
+
+		ret = usb_submit_urb(urb, GFP_KERNEL);
+		if (ret) {
+			usb_unanchor_urb(urb);
+			usb_free_coherent(es58x_dev->udev, rx_buf_len,
+					  buf, urb->transfer_dma);
+			usb_free_urb(urb);
+			break;
+		}
+		usb_free_urb(urb);
+	}
+
+	if (i == 0) {
+		dev_err(dev, "%s: Could not setup any rx URBs\n", __func__);
+		return ret;
+	}
+	dev_dbg(dev, "%s: Allocated %d rx URBs each of size %zu\n",
+		__func__, i, rx_buf_len);
+
+	return ret;
+}
+
+/**
+ * es58x_free_urbs() - Free all the TX and RX URBs.
+ * @es58x_dev: ES58X device.
+ */
+static void es58x_free_urbs(struct es58x_device *es58x_dev)
+{
+	struct urb *urb;
+
+	if (!usb_wait_anchor_empty_timeout(&es58x_dev->tx_urbs_busy, 1000)) {
+		dev_err(es58x_dev->dev, "%s: Timeout, some TX urbs still remain\n",
+			__func__);
+		usb_kill_anchored_urbs(&es58x_dev->tx_urbs_busy);
+	}
+
+	while ((urb = usb_get_from_anchor(&es58x_dev->tx_urbs_idle)) != NULL) {
+		usb_free_coherent(urb->dev, es58x_dev->param->tx_urb_cmd_max_len,
+				  urb->transfer_buffer, urb->transfer_dma);
+		usb_free_urb(urb);
+		atomic_dec(&es58x_dev->tx_urbs_idle_cnt);
+	}
+	if (atomic_read(&es58x_dev->tx_urbs_idle_cnt))
+		dev_err(es58x_dev->dev,
+			"All idle urbs were freed but tx_urb_idle_cnt is %d\n",
+			atomic_read(&es58x_dev->tx_urbs_idle_cnt));
+
+	usb_kill_anchored_urbs(&es58x_dev->rx_urbs);
+}
+
+/**
+ * es58x_open() - Enable the network device.
+ * @netdev: CAN network device.
+ *
+ * Called when the network transitions to the up state. Allocate the
+ * URB resources if needed and open the channel.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_open(struct net_device *netdev)
+{
+	struct es58x_device *es58x_dev = es58x_priv(netdev)->es58x_dev;
+	int ret;
+
+	if (atomic_inc_return(&es58x_dev->opened_channel_cnt) == 1) {
+		ret = es58x_alloc_rx_urbs(es58x_dev);
+		if (ret)
+			return ret;
+
+		ret = es58x_set_realtime_diff_ns(es58x_dev);
+		if (ret)
+			goto free_urbs;
+	}
+
+	ret = open_candev(netdev);
+	if (ret)
+		goto free_urbs;
+
+	ret = es58x_dev->ops->enable_channel(es58x_priv(netdev));
+	if (ret)
+		goto free_urbs;
+
+	netif_start_queue(netdev);
+
+	return ret;
+
+ free_urbs:
+	if (atomic_dec_and_test(&es58x_dev->opened_channel_cnt))
+		es58x_free_urbs(es58x_dev);
+	netdev_err(netdev, "%s: Could not open the network device: %pe\n",
+		   __func__, ERR_PTR(ret));
+
+	return ret;
+}
+
+/**
+ * es58x_stop() - Disable the network device.
+ * @netdev: CAN network device.
+ *
+ * Called when the network transitions to the down state. If all the
+ * channels of the device are closed, free the URB resources which are
+ * not needed anymore.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_stop(struct net_device *netdev)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	struct es58x_device *es58x_dev = priv->es58x_dev;
+	int ret;
+
+	netif_stop_queue(netdev);
+	ret = es58x_dev->ops->disable_channel(priv);
+	if (ret)
+		return ret;
+
+	priv->can.state = CAN_STATE_STOPPED;
+	es58x_can_reset_echo_fifo(netdev);
+	close_candev(netdev);
+
+	es58x_flush_pending_tx_msg(netdev);
+
+	if (atomic_dec_and_test(&es58x_dev->opened_channel_cnt))
+		es58x_free_urbs(es58x_dev);
+
+	return 0;
+}
+
+/**
+ * es58x_xmit_commit() - Send the bulk urb.
+ * @netdev: CAN network device.
+ *
+ * Do the bulk send. This function should be called only once by bulk
+ * transmission.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_xmit_commit(struct net_device *netdev)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	int ret;
+
+	if (!es58x_is_can_state_active(netdev))
+		return -ENETDOWN;
+
+	if (es58x_is_echo_skb_threshold_reached(priv))
+		netif_stop_queue(netdev);
+
+	ret = es58x_submit_urb(priv->es58x_dev, priv->tx_urb, netdev);
+	if (ret == 0)
+		priv->tx_urb = NULL;
+
+	return ret;
+}
+
+/**
+ * es58x_xmit_more() - Can we put more packets?
+ * @priv: ES58X private parameters related to the network device.
+ *
+ * Return: true if we can put more, false if it is time to send.
+ */
+static bool es58x_xmit_more(struct es58x_priv *priv)
+{
+	unsigned int free_slots =
+	    priv->can.echo_skb_max - (priv->tx_head - priv->tx_tail);
+
+	return netdev_xmit_more() && free_slots > 0 &&
+		priv->tx_can_msg_cnt < priv->es58x_dev->param->tx_bulk_max;
+}
+
+/**
+ * es58x_start_xmit() - Transmit an skb.
+ * @skb: socket buffer of a CAN message.
+ * @netdev: CAN network device.
+ *
+ * Called when a packet needs to be transmitted.
+ *
+ * This function relies on Byte Queue Limits (BQL). The main benefit
+ * is to increase the throughput by allowing bulk transfers
+ * (c.f. xmit_more flag).
+ *
+ * Queues up to tx_bulk_max messages in &tx_urb buffer and does
+ * a bulk send of all messages in one single URB.
+ *
+ * Return: NETDEV_TX_OK regardless of if we could transmit the @skb or
+ *	had to drop it.
+ */
+static netdev_tx_t es58x_start_xmit(struct sk_buff *skb,
+				    struct net_device *netdev)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	struct es58x_device *es58x_dev = priv->es58x_dev;
+	unsigned int frame_len;
+	int ret;
+
+	if (can_dropped_invalid_skb(netdev, skb)) {
+		if (priv->tx_urb)
+			goto xmit_commit;
+		return NETDEV_TX_OK;
+	}
+
+	if (priv->tx_urb && priv->tx_can_msg_is_fd != can_is_canfd_skb(skb)) {
+		/* Can not do bulk send with mixed CAN and CAN FD frames. */
+		ret = es58x_xmit_commit(netdev);
+		if (ret)
+			goto drop_skb;
+	}
+
+	if (!priv->tx_urb) {
+		priv->tx_urb = es58x_get_tx_urb(es58x_dev);
+		if (!priv->tx_urb) {
+			ret = -ENOMEM;
+			goto drop_skb;
+		}
+		priv->tx_can_msg_cnt = 0;
+		priv->tx_can_msg_is_fd = can_is_canfd_skb(skb);
+	}
+
+	ret = es58x_dev->ops->tx_can_msg(priv, skb);
+	if (ret)
+		goto drop_skb;
+
+	frame_len = can_skb_get_frame_len(skb);
+	ret = can_put_echo_skb(skb, netdev,
+			       priv->tx_head & es58x_dev->param->fifo_mask,
+			       frame_len);
+	if (ret)
+		goto xmit_failure;
+	netdev_sent_queue(netdev, frame_len);
+
+	priv->tx_head++;
+	priv->tx_can_msg_cnt++;
+
+ xmit_commit:
+	if (!es58x_xmit_more(priv)) {
+		ret = es58x_xmit_commit(netdev);
+		if (ret)
+			goto xmit_failure;
+	}
+
+	return NETDEV_TX_OK;
+
+ drop_skb:
+	dev_kfree_skb(skb);
+	netdev->stats.tx_dropped++;
+ xmit_failure:
+	netdev_warn(netdev, "%s: send message failure: %pe\n",
+		    __func__, ERR_PTR(ret));
+	netdev->stats.tx_errors++;
+	es58x_flush_pending_tx_msg(netdev);
+	return NETDEV_TX_OK;
+}
+
+static const struct net_device_ops es58x_netdev_ops = {
+	.ndo_open = es58x_open,
+	.ndo_stop = es58x_stop,
+	.ndo_start_xmit = es58x_start_xmit
+};
+
+/**
+ * es58x_set_mode() - Change network device mode.
+ * @netdev: CAN network device.
+ * @mode: either %CAN_MODE_START, %CAN_MODE_STOP or %CAN_MODE_SLEEP
+ *
+ * Currently, this function is only used to stop and restart the
+ * channel during a bus off event (c.f. es58x_rx_err_msg() and
+ * drivers/net/can/dev.c:can_restart() which are the two only
+ * callers).
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_set_mode(struct net_device *netdev, enum can_mode mode)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+
+	switch (mode) {
+	case CAN_MODE_START:
+		switch (priv->can.state) {
+		case CAN_STATE_BUS_OFF:
+			return priv->es58x_dev->ops->enable_channel(priv);
+
+		case CAN_STATE_STOPPED:
+			return es58x_open(netdev);
+
+		case CAN_STATE_ERROR_ACTIVE:
+		case CAN_STATE_ERROR_WARNING:
+		case CAN_STATE_ERROR_PASSIVE:
+		default:
+			return 0;
+		}
+
+	case CAN_MODE_STOP:
+		switch (priv->can.state) {
+		case CAN_STATE_STOPPED:
+			return 0;
+
+		case CAN_STATE_ERROR_ACTIVE:
+		case CAN_STATE_ERROR_WARNING:
+		case CAN_STATE_ERROR_PASSIVE:
+		case CAN_STATE_BUS_OFF:
+		default:
+			return priv->es58x_dev->ops->disable_channel(priv);
+		}
+
+	case CAN_MODE_SLEEP:
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+/**
+ * es58x_init_priv() - Initialize private parameters.
+ * @es58x_dev: ES58X device.
+ * @priv: ES58X private parameters related to the network device.
+ * @channel_idx: Index of the network device.
+ */
+static void es58x_init_priv(struct es58x_device *es58x_dev,
+			    struct es58x_priv *priv, int channel_idx)
+{
+	const struct es58x_parameters *param = es58x_dev->param;
+	struct can_priv *can = &priv->can;
+
+	priv->es58x_dev = es58x_dev;
+	priv->channel_idx = channel_idx;
+	priv->tx_urb = NULL;
+	priv->tx_can_msg_cnt = 0;
+
+	can->bittiming_const = param->bittiming_const;
+	if (param->ctrlmode_supported & CAN_CTRLMODE_FD) {
+		can->data_bittiming_const = param->data_bittiming_const;
+		can->tdc_const = param->tdc_const;
+	}
+	can->bitrate_max = param->bitrate_max;
+	can->clock = param->clock;
+	can->state = CAN_STATE_STOPPED;
+	can->ctrlmode_supported = param->ctrlmode_supported;
+	can->do_set_mode = es58x_set_mode;
+}
+
+/**
+ * es58x_init_netdev() - Initialize the network device.
+ * @es58x_dev: ES58X device.
+ * @channel_idx: Index of the network device.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_init_netdev(struct es58x_device *es58x_dev, int channel_idx)
+{
+	struct net_device *netdev;
+	struct device *dev = es58x_dev->dev;
+	int ret;
+
+	netdev = alloc_candev(sizeof(struct es58x_priv),
+			      es58x_dev->param->fifo_mask + 1);
+	if (!netdev) {
+		dev_err(dev, "Could not allocate candev\n");
+		return -ENOMEM;
+	}
+	SET_NETDEV_DEV(netdev, dev);
+	es58x_dev->netdev[channel_idx] = netdev;
+	es58x_init_priv(es58x_dev, es58x_priv(netdev), channel_idx);
+
+	netdev->netdev_ops = &es58x_netdev_ops;
+	netdev->flags |= IFF_ECHO;	/* We support local echo */
+
+	ret = register_candev(netdev);
+	if (ret)
+		return ret;
+
+	netdev_queue_set_dql_min_limit(netdev_get_tx_queue(netdev, 0),
+				       es58x_dev->param->dql_min_limit);
+
+	return ret;
+}
+
+/**
+ * es58x_get_product_info() - Get the product information and print them.
+ * @es58x_dev: ES58X device.
+ *
+ * Do a synchronous call to get the product information.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_get_product_info(struct es58x_device *es58x_dev)
+{
+	struct usb_device *udev = es58x_dev->udev;
+	const int es58x_prod_info_idx = 6;
+	/* Empirical tests show a prod_info length of maximum 83,
+	 * below should be more than enough.
+	 */
+	const size_t prod_info_len = 127;
+	char *prod_info;
+	int ret;
+
+	prod_info = kmalloc(prod_info_len, GFP_KERNEL);
+	if (!prod_info)
+		return -ENOMEM;
+
+	ret = usb_string(udev, es58x_prod_info_idx, prod_info, prod_info_len);
+	if (ret < 0) {
+		dev_err(es58x_dev->dev,
+			"%s: Could not read the product info: %pe\n",
+			__func__, ERR_PTR(ret));
+		goto out_free;
+	}
+	if (ret >= prod_info_len - 1) {
+		dev_warn(es58x_dev->dev,
+			 "%s: Buffer is too small, result might be truncated\n",
+			 __func__);
+	}
+	dev_info(es58x_dev->dev, "Product info: %s\n", prod_info);
+
+ out_free:
+	kfree(prod_info);
+	return ret < 0 ? ret : 0;
+}
+
+/**
+ * es58x_init_es58x_dev() - Initialize the ES58X device.
+ * @intf: USB interface.
+ * @p_es58x_dev: pointer to the address of the ES58X device.
+ * @driver_info: Quirks of the device.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_init_es58x_dev(struct usb_interface *intf,
+				struct es58x_device **p_es58x_dev,
+				kernel_ulong_t driver_info)
+{
+	struct device *dev = &intf->dev;
+	struct es58x_device *es58x_dev;
+	const struct es58x_parameters *param;
+	const struct es58x_operators *ops;
+	struct usb_device *udev = interface_to_usbdev(intf);
+	struct usb_endpoint_descriptor *ep_in, *ep_out;
+	int ret;
+
+	dev_info(dev,
+		 "Starting %s %s (Serial Number %s) driver version %s\n",
+		 udev->manufacturer, udev->product, udev->serial, DRV_VERSION);
+
+	ret = usb_find_common_endpoints(intf->cur_altsetting, &ep_in, &ep_out,
+					NULL, NULL);
+	if (ret)
+		return ret;
+
+	if (driver_info & ES58X_FD_FAMILY) {
+		param = &es58x_fd_param;
+		ops = &es58x_fd_ops;
+	} else {
+		param = &es581_4_param;
+		ops = &es581_4_ops;
+	}
+
+	es58x_dev = kzalloc(es58x_sizeof_es58x_device(param), GFP_KERNEL);
+	if (!es58x_dev)
+		return -ENOMEM;
+
+	es58x_dev->param = param;
+	es58x_dev->ops = ops;
+	es58x_dev->dev = dev;
+	es58x_dev->udev = udev;
+
+	if (driver_info & ES58X_DUAL_CHANNEL)
+		es58x_dev->num_can_ch = 2;
+	else
+		es58x_dev->num_can_ch = 1;
+
+	init_usb_anchor(&es58x_dev->rx_urbs);
+	init_usb_anchor(&es58x_dev->tx_urbs_idle);
+	init_usb_anchor(&es58x_dev->tx_urbs_busy);
+	atomic_set(&es58x_dev->tx_urbs_idle_cnt, 0);
+	atomic_set(&es58x_dev->opened_channel_cnt, 0);
+	usb_set_intfdata(intf, es58x_dev);
+
+	es58x_dev->rx_pipe = usb_rcvbulkpipe(es58x_dev->udev,
+					     ep_in->bEndpointAddress);
+	es58x_dev->tx_pipe = usb_sndbulkpipe(es58x_dev->udev,
+					     ep_out->bEndpointAddress);
+	es58x_dev->rx_max_packet_size = le16_to_cpu(ep_in->wMaxPacketSize);
+
+	*p_es58x_dev = es58x_dev;
+
+	return 0;
+}
+
+/**
+ * es58x_probe() - Initialize the USB device.
+ * @intf: USB interface.
+ * @id: USB device ID.
+ *
+ * Return: zero on success, -ENODEV if the interface is not supported
+ * or errno when any other error occurs.
+ */
+static int es58x_probe(struct usb_interface *intf,
+		       const struct usb_device_id *id)
+{
+	struct es58x_device *es58x_dev;
+	int ch_idx, ret;
+
+	ret = es58x_init_es58x_dev(intf, &es58x_dev, id->driver_info);
+	if (ret)
+		return ret;
+
+	ret = es58x_get_product_info(es58x_dev);
+	if (ret)
+		goto cleanup_es58x_dev;
+
+	for (ch_idx = 0; ch_idx < es58x_dev->num_can_ch; ch_idx++) {
+		ret = es58x_init_netdev(es58x_dev, ch_idx);
+		if (ret)
+			goto cleanup_candev;
+	}
+
+	return ret;
+
+ cleanup_candev:
+	for (ch_idx = 0; ch_idx < es58x_dev->num_can_ch; ch_idx++)
+		if (es58x_dev->netdev[ch_idx]) {
+			unregister_candev(es58x_dev->netdev[ch_idx]);
+			free_candev(es58x_dev->netdev[ch_idx]);
+		}
+ cleanup_es58x_dev:
+	kfree(es58x_dev);
+
+	return ret;
+}
+
+/**
+ * es58x_disconnect() - Disconnect the USB device.
+ * @intf: USB interface
+ *
+ * Called by the usb core when driver is unloaded or device is
+ * removed.
+ */
+static void es58x_disconnect(struct usb_interface *intf)
+{
+	struct es58x_device *es58x_dev = usb_get_intfdata(intf);
+	struct net_device *netdev;
+	int i;
+
+	dev_info(&intf->dev, "Disconnecting %s %s\n",
+		 es58x_dev->udev->manufacturer, es58x_dev->udev->product);
+
+	for (i = 0; i < es58x_dev->num_can_ch; i++) {
+		netdev = es58x_dev->netdev[i];
+		if (!netdev)
+			continue;
+		unregister_candev(netdev);
+		es58x_dev->netdev[i] = NULL;
+		free_candev(netdev);
+	}
+
+	es58x_free_urbs(es58x_dev);
+
+	kfree(es58x_dev);
+	usb_set_intfdata(intf, NULL);
+}
+
+static struct usb_driver es58x_driver = {
+	.name = ES58X_MODULE_NAME,
+	.probe = es58x_probe,
+	.disconnect = es58x_disconnect,
+	.id_table = es58x_id_table
+};
+
+module_usb_driver(es58x_driver);

drivers/net/can/usb/etas_es58x/es58x_core.h

+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* Driver for ETAS GmbH ES58X USB CAN(-FD) Bus Interfaces.
+ *
+ * File es58x_core.h: All common definitions and declarations.
+ *
+ * Copyright (c) 2019 Robert Bosch Engineering and Business Solutions. All rights reserved.
+ * Copyright (c) 2020 ETAS K.K.. All rights reserved.
+ * Copyright (c) 2020, 2021 Vincent Mailhol <mailhol.vincent@wanadoo.fr>
+ */
+
+#ifndef __ES58X_COMMON_H__
+#define __ES58X_COMMON_H__
+
+#include <linux/types.h>
+#include <linux/usb.h>
+#include <linux/netdevice.h>
+#include <linux/can.h>
+#include <linux/can/dev.h>
+
+#include "es581_4.h"
+#include "es58x_fd.h"
+
+/* Driver constants */
+#define ES58X_RX_URBS_MAX 5	/* Empirical value */
+#define ES58X_TX_URBS_MAX 6	/* Empirical value */
+
+#define ES58X_MAX(param)				\
+	(ES581_4_##param > ES58X_FD_##param ?		\
+		ES581_4_##param : ES58X_FD_##param)
+#define ES58X_TX_BULK_MAX ES58X_MAX(TX_BULK_MAX)
+#define ES58X_RX_BULK_MAX ES58X_MAX(RX_BULK_MAX)
+#define ES58X_ECHO_BULK_MAX ES58X_MAX(ECHO_BULK_MAX)
+#define ES58X_NUM_CAN_CH_MAX ES58X_MAX(NUM_CAN_CH)
+
+/* Use this when channel index is irrelevant (e.g. device
+ * timestamp).
+ */
+#define ES58X_CHANNEL_IDX_NA 0xFF
+#define ES58X_EMPTY_MSG NULL
+
+/* Threshold on consecutive CAN_STATE_ERROR_PASSIVE. If we receive
+ * ES58X_CONSECUTIVE_ERR_PASSIVE_MAX times the event
+ * ES58X_ERR_CRTL_PASSIVE in a row without any successful RX or TX,
+ * we force the device to switch to CAN_STATE_BUS_OFF state.
+ */
+#define ES58X_CONSECUTIVE_ERR_PASSIVE_MAX 254
+
+/* A magic number sent by the ES581.4 to inform it is alive. */
+#define ES58X_HEARTBEAT 0x11
+
+/**
+ * enum es58x_driver_info - Quirks of the device.
+ * @ES58X_DUAL_CHANNEL: Device has two CAN channels. If this flag is
+ *	not set, it is implied that the device has only one CAN
+ *	channel.
+ * @ES58X_FD_FAMILY: Device is CAN-FD capable. If this flag is not
+ *	set, the device only supports classical CAN.
+ */
+enum es58x_driver_info {
+	ES58X_DUAL_CHANNEL = BIT(0),
+	ES58X_FD_FAMILY = BIT(1)
+};
+
+enum es58x_echo {
+	ES58X_ECHO_OFF = 0,
+	ES58X_ECHO_ON = 1
+};
+
+/**
+ * enum es58x_physical_layer - Type of the physical layer.
+ * @ES58X_PHYSICAL_LAYER_HIGH_SPEED: High-speed CAN (c.f. ISO
+ *	11898-2).
+ *
+ * Some products of the ETAS portfolio also support low-speed CAN
+ * (c.f. ISO 11898-3). However, all the devices in scope of this
+ * driver do not support the option, thus, the enum has only one
+ * member.
+ */
+enum es58x_physical_layer {
+	ES58X_PHYSICAL_LAYER_HIGH_SPEED = 1
+};
+
+enum es58x_samples_per_bit {
+	ES58X_SAMPLES_PER_BIT_ONE = 1,
+	ES58X_SAMPLES_PER_BIT_THREE = 2
+};
+
+/**
+ * enum es58x_sync_edge - Synchronization method.
+ * @ES58X_SYNC_EDGE_SINGLE: ISO CAN specification defines the use of a
+ *	single edge synchronization.  The synchronization should be
+ *	done on recessive to dominant level change.
+ *
+ * For information, ES582.1 and ES584.1 also support a double
+ * synchronization, requiring both recessive to dominant then dominant
+ * to recessive level change. However, this is not supported in
+ * SocketCAN framework, thus, the enum has only one member.
+ */
+enum es58x_sync_edge {
+	ES58X_SYNC_EDGE_SINGLE = 1
+};
+
+/**
+ * enum es58x_flag - CAN flags for RX/TX messages.
+ * @ES58X_FLAG_EFF: Extended Frame Format (EFF).
+ * @ES58X_FLAG_RTR: Remote Transmission Request (RTR).
+ * @ES58X_FLAG_FD_BRS: Bit rate switch (BRS): second bitrate for
+ *	payload data.
+ * @ES58X_FLAG_FD_ESI: Error State Indicator (ESI): tell if the
+ *	transmitting node is in error passive mode.
+ * @ES58X_FLAG_FD_DATA: CAN FD frame.
+ */
+enum es58x_flag {
+	ES58X_FLAG_EFF = BIT(0),
+	ES58X_FLAG_RTR = BIT(1),
+	ES58X_FLAG_FD_BRS = BIT(3),
+	ES58X_FLAG_FD_ESI = BIT(5),
+	ES58X_FLAG_FD_DATA = BIT(6)
+};
+
+/**
+ * enum es58x_err - CAN error detection.
+ * @ES58X_ERR_OK: No errors.
+ * @ES58X_ERR_PROT_STUFF: Bit stuffing error: more than 5 consecutive
+ *	equal bits.
+ * @ES58X_ERR_PROT_FORM: Frame format error.
+ * @ES58X_ERR_ACK: Received no ACK on transmission.
+ * @ES58X_ERR_PROT_BIT: Single bit error.
+ * @ES58X_ERR_PROT_CRC: Incorrect 15, 17 or 21 bits CRC.
+ * @ES58X_ERR_PROT_BIT1: Unable to send recessive bit: tried to send
+ *	recessive bit 1 but monitored dominant bit 0.
+ * @ES58X_ERR_PROT_BIT0: Unable to send dominant bit: tried to send
+ *	dominant bit 0 but monitored recessive bit 1.
+ * @ES58X_ERR_PROT_OVERLOAD: Bus overload.
+ * @ES58X_ERR_PROT_UNSPEC: Unspecified.
+ *
+ * Please refer to ISO 11898-1:2015, section 10.11 "Error detection"
+ * and section 10.13 "Overload signaling" for additional details.
+ */
+enum es58x_err {
+	ES58X_ERR_OK = 0,
+	ES58X_ERR_PROT_STUFF = BIT(0),
+	ES58X_ERR_PROT_FORM = BIT(1),
+	ES58X_ERR_ACK = BIT(2),
+	ES58X_ERR_PROT_BIT = BIT(3),
+	ES58X_ERR_PROT_CRC = BIT(4),
+	ES58X_ERR_PROT_BIT1 = BIT(5),
+	ES58X_ERR_PROT_BIT0 = BIT(6),
+	ES58X_ERR_PROT_OVERLOAD = BIT(7),
+	ES58X_ERR_PROT_UNSPEC = BIT(31)
+};
+
+/**
+ * enum es58x_event - CAN error codes returned by the device.
+ * @ES58X_EVENT_OK: No errors.
+ * @ES58X_EVENT_CRTL_ACTIVE: Active state: both TR and RX error count
+ *	is less than 128.
+ * @ES58X_EVENT_CRTL_PASSIVE: Passive state: either TX or RX error
+ *	count is greater than 127.
+ * @ES58X_EVENT_CRTL_WARNING: Warning state: either TX or RX error
+ *	count is greater than 96.
+ * @ES58X_EVENT_BUSOFF: Bus off.
+ * @ES58X_EVENT_SINGLE_WIRE: Lost connection on either CAN high or CAN
+ *	low.
+ *
+ * Please refer to ISO 11898-1:2015, section 12.1.4 "Rules of fault
+ * confinement" for additional details.
+ */
+enum es58x_event {
+	ES58X_EVENT_OK = 0,
+	ES58X_EVENT_CRTL_ACTIVE = BIT(0),
+	ES58X_EVENT_CRTL_PASSIVE = BIT(1),
+	ES58X_EVENT_CRTL_WARNING = BIT(2),
+	ES58X_EVENT_BUSOFF = BIT(3),
+	ES58X_EVENT_SINGLE_WIRE = BIT(4)
+};
+
+/* enum es58x_ret_u8 - Device return error codes, 8 bit format.
+ *
+ * Specific to ES581.4.
+ */
+enum es58x_ret_u8 {
+	ES58X_RET_U8_OK = 0x00,
+	ES58X_RET_U8_ERR_UNSPECIFIED_FAILURE = 0x80,
+	ES58X_RET_U8_ERR_NO_MEM = 0x81,
+	ES58X_RET_U8_ERR_BAD_CRC = 0x99
+};
+
+/* enum es58x_ret_u32 - Device return error codes, 32 bit format.
+ */
+enum es58x_ret_u32 {
+	ES58X_RET_U32_OK = 0x00000000UL,
+	ES58X_RET_U32_ERR_UNSPECIFIED_FAILURE = 0x80000000UL,
+	ES58X_RET_U32_ERR_NO_MEM = 0x80004001UL,
+	ES58X_RET_U32_WARN_PARAM_ADJUSTED = 0x40004000UL,
+	ES58X_RET_U32_WARN_TX_MAYBE_REORDER = 0x40004001UL,
+	ES58X_RET_U32_ERR_TIMEDOUT = 0x80000008UL,
+	ES58X_RET_U32_ERR_FIFO_FULL = 0x80003002UL,
+	ES58X_RET_U32_ERR_BAD_CONFIG = 0x80004000UL,
+	ES58X_RET_U32_ERR_NO_RESOURCE = 0x80004002UL
+};
+
+/* enum es58x_ret_type - Type of the command returned by the ES58X
+ *	device.
+ */
+enum es58x_ret_type {
+	ES58X_RET_TYPE_SET_BITTIMING,
+	ES58X_RET_TYPE_ENABLE_CHANNEL,
+	ES58X_RET_TYPE_DISABLE_CHANNEL,
+	ES58X_RET_TYPE_TX_MSG,
+	ES58X_RET_TYPE_RESET_RX,
+	ES58X_RET_TYPE_RESET_TX,
+	ES58X_RET_TYPE_DEVICE_ERR
+};
+
+union es58x_urb_cmd {
+	struct es581_4_urb_cmd es581_4_urb_cmd;
+	struct es58x_fd_urb_cmd es58x_fd_urb_cmd;
+	struct {		/* Common header parts of all variants */
+		__le16 sof;
+		u8 cmd_type;
+		u8 cmd_id;
+	} __packed;
+	u8 raw_cmd[0];
+};
+
+/**
+ * struct es58x_priv - All information specific to a CAN channel.
+ * @can: struct can_priv must be the first member (Socket CAN relies
+ *	on the fact that function netdev_priv() returns a pointer to
+ *	a struct can_priv).
+ * @es58x_dev: pointer to the corresponding ES58X device.
+ * @tx_urb: Used as a buffer to concatenate the TX messages and to do
+ *	a bulk send. Please refer to es58x_start_xmit() for more
+ *	details.
+ * @tx_tail: Index of the oldest packet still pending for
+ *	completion. @tx_tail & echo_skb_mask represents the beginning
+ *	of the echo skb FIFO, i.e. index of the first element.
+ * @tx_head: Index of the next packet to be sent to the
+ *	device. @tx_head & echo_skb_mask represents the end of the
+ *	echo skb FIFO plus one, i.e. the first free index.
+ * @tx_can_msg_cnt: Number of messages in @tx_urb.
+ * @tx_can_msg_is_fd: false: all messages in @tx_urb are Classical
+ *	CAN, true: all messages in @tx_urb are CAN FD. Rationale:
+ *	ES58X FD devices do not allow to mix Classical CAN and FD CAN
+ *	frames in one single bulk transmission.
+ * @err_passive_before_rtx_success: The ES58X device might enter in a
+ *	state in which it keeps alternating between error passive
+ *	and active states. This counter keeps track of the number of
+ *	error passive and if it gets bigger than
+ *	ES58X_CONSECUTIVE_ERR_PASSIVE_MAX, es58x_rx_err_msg() will
+ *	force the status to bus-off.
+ * @channel_idx: Channel index, starts at zero.
+ */
+struct es58x_priv {
+	struct can_priv can;
+	struct es58x_device *es58x_dev;
+	struct urb *tx_urb;
+
+	u32 tx_tail;
+	u32 tx_head;
+
+	u8 tx_can_msg_cnt;
+	bool tx_can_msg_is_fd;
+
+	u8 err_passive_before_rtx_success;
+
+	u8 channel_idx;
+};
+
+/**
+ * struct es58x_parameters - Constant parameters of a given hardware
+ *	variant.
+ * @bittiming_const: Nominal bittimming constant parameters.
+ * @data_bittiming_const: Data bittiming constant parameters.
+ * @tdc_const: Transmission Delay Compensation constant parameters.
+ * @bitrate_max: Maximum bitrate supported by the device.
+ * @clock: CAN clock parameters.
+ * @ctrlmode_supported: List of supported modes. Please refer to
+ *	can/netlink.h file for additional details.
+ * @tx_start_of_frame: Magic number at the beginning of each TX URB
+ *	command.
+ * @rx_start_of_frame: Magic number at the beginning of each RX URB
+ *	command.
+ * @tx_urb_cmd_max_len: Maximum length of a TX URB command.
+ * @rx_urb_cmd_max_len: Maximum length of a RX URB command.
+ * @fifo_mask: Bit mask to quickly convert the tx_tail and tx_head
+ *	field of the struct es58x_priv into echo_skb
+ *	indexes. Properties: @fifo_mask = echos_skb_max - 1 where
+ *	echo_skb_max must be a power of two. Also, echo_skb_max must
+ *	not exceed the maximum size of the device internal TX FIFO
+ *	length. This parameter is used to control the network queue
+ *	wake/stop logic.
+ * @dql_min_limit: Dynamic Queue Limits (DQL) absolute minimum limit
+ *	of bytes allowed to be queued on this network device transmit
+ *	queue. Used by the Byte Queue Limits (BQL) to determine how
+ *	frequently the xmit_more flag will be set to true in
+ *	es58x_start_xmit(). Set this value higher to optimize for
+ *	throughput but be aware that it might have a negative impact
+ *	on the latency! This value can also be set dynamically. Please
+ *	refer to Documentation/ABI/testing/sysfs-class-net-queues for
+ *	more details.
+ * @tx_bulk_max: Maximum number of TX messages that can be sent in one
+ *	single URB packet.
+ * @urb_cmd_header_len: Length of the URB command header.
+ * @rx_urb_max: Number of RX URB to be allocated during device probe.
+ * @tx_urb_max: Number of TX URB to be allocated during device probe.
+ */
+struct es58x_parameters {
+	const struct can_bittiming_const *bittiming_const;
+	const struct can_bittiming_const *data_bittiming_const;
+	const struct can_tdc_const *tdc_const;
+	u32 bitrate_max;
+	struct can_clock clock;
+	u32 ctrlmode_supported;
+	u16 tx_start_of_frame;
+	u16 rx_start_of_frame;
+	u16 tx_urb_cmd_max_len;
+	u16 rx_urb_cmd_max_len;
+	u16 fifo_mask;
+	u16 dql_min_limit;
+	u8 tx_bulk_max;
+	u8 urb_cmd_header_len;
+	u8 rx_urb_max;
+	u8 tx_urb_max;
+};
+
+/**
+ * struct es58x_operators - Function pointers used to encode/decode
+ *	the TX/RX messages.
+ * @get_msg_len: Get field msg_len of the urb_cmd. The offset of
+ *	msg_len inside urb_cmd depends of the device model.
+ * @handle_urb_cmd: Decode the URB command received from the device
+ *	and dispatch it to the relevant sub function.
+ * @fill_urb_header: Fill the header of urb_cmd.
+ * @tx_can_msg: Encode a TX CAN message and add it to the bulk buffer
+ *	cmd_buf of es58x_dev.
+ * @enable_channel: Start the CAN channel.
+ * @disable_channel: Stop the CAN channel.
+ * @reset_device: Full reset of the device. N.B: this feature is only
+ *	present on the ES581.4. For ES58X FD devices, this field is
+ *	set to NULL.
+ * @get_timestamp: Request a timestamp from the ES58X device.
+ */
+struct es58x_operators {
+	u16 (*get_msg_len)(const union es58x_urb_cmd *urb_cmd);
+	int (*handle_urb_cmd)(struct es58x_device *es58x_dev,
+			      const union es58x_urb_cmd *urb_cmd);
+	void (*fill_urb_header)(union es58x_urb_cmd *urb_cmd, u8 cmd_type,
+				u8 cmd_id, u8 channel_idx, u16 cmd_len);
+	int (*tx_can_msg)(struct es58x_priv *priv, const struct sk_buff *skb);
+	int (*enable_channel)(struct es58x_priv *priv);
+	int (*disable_channel)(struct es58x_priv *priv);
+	int (*reset_device)(struct es58x_device *es58x_dev);
+	int (*get_timestamp)(struct es58x_device *es58x_dev);
+};
+
+/**
+ * struct es58x_device - All information specific to an ES58X device.
+ * @dev: Device information.
+ * @udev: USB device information.
+ * @netdev: Array of our CAN channels.
+ * @param: The constant parameters.
+ * @ops: Operators.
+ * @rx_pipe: USB reception pipe.
+ * @tx_pipe: USB transmission pipe.
+ * @rx_urbs: Anchor for received URBs.
+ * @tx_urbs_busy: Anchor for TX URBs which were send to the device.
+ * @tx_urbs_idle: Anchor for TX USB which are idle. This driver
+ *	allocates the memory for the URBs during the probe. When a TX
+ *	URB is needed, it can be taken from this anchor. The network
+ *	queue wake/stop logic should prevent this URB from getting
+ *	empty. Please refer to es58x_get_tx_urb() for more details.
+ * @tx_urbs_idle_cnt: number of urbs in @tx_urbs_idle.
+ * @opened_channel_cnt: number of channels opened (c.f. es58x_open()
+ *	and es58x_stop()).
+ * @ktime_req_ns: kernel timestamp when es58x_set_realtime_diff_ns()
+ *	was called.
+ * @realtime_diff_ns: difference in nanoseconds between the clocks of
+ *	the ES58X device and the kernel.
+ * @timestamps: a temporary buffer to store the time stamps before
+ *	feeding them to es58x_can_get_echo_skb(). Can only be used
+ *	in RX branches.
+ * @rx_max_packet_size: Maximum length of bulk-in URB.
+ * @num_can_ch: Number of CAN channel (i.e. number of elements of @netdev).
+ * @rx_cmd_buf_len: Length of @rx_cmd_buf.
+ * @rx_cmd_buf: The device might split the URB commands in an
+ *	arbitrary amount of pieces. This buffer is used to concatenate
+ *	all those pieces. Can only be used in RX branches. This field
+ *	has to be the last one of the structure because it is has a
+ *	flexible size (c.f. es58x_sizeof_es58x_device() function).
+ */
+struct es58x_device {
+	struct device *dev;
+	struct usb_device *udev;
+	struct net_device *netdev[ES58X_NUM_CAN_CH_MAX];
+
+	const struct es58x_parameters *param;
+	const struct es58x_operators *ops;
+
+	int rx_pipe;
+	int tx_pipe;
+
+	struct usb_anchor rx_urbs;
+	struct usb_anchor tx_urbs_busy;
+	struct usb_anchor tx_urbs_idle;
+	atomic_t tx_urbs_idle_cnt;
+	atomic_t opened_channel_cnt;
+
+	u64 ktime_req_ns;
+	s64 realtime_diff_ns;
+
+	u64 timestamps[ES58X_ECHO_BULK_MAX];
+
+	u16 rx_max_packet_size;
+	u8 num_can_ch;
+
+	u16 rx_cmd_buf_len;
+	union es58x_urb_cmd rx_cmd_buf;
+};
+
+/**
+ * es58x_sizeof_es58x_device() - Calculate the maximum length of
+ *	struct es58x_device.
+ * @es58x_dev_param: The constant parameters of the device.
+ *
+ * The length of struct es58x_device depends on the length of its last
+ * field: rx_cmd_buf. This macro allows to optimize the memory
+ * allocation.
+ *
+ * Return: length of struct es58x_device.
+ */
+static inline size_t es58x_sizeof_es58x_device(const struct es58x_parameters
+					       *es58x_dev_param)
+{
+	return offsetof(struct es58x_device, rx_cmd_buf) +
+		es58x_dev_param->rx_urb_cmd_max_len;
+}
+
+static inline int __es58x_check_msg_len(const struct device *dev,
+					const char *stringified_msg,
+					size_t actual_len, size_t expected_len)
+{
+	if (expected_len != actual_len) {
+		dev_err(dev,
+			"Length of %s is %zu but received command is %zu.\n",
+			stringified_msg, expected_len, actual_len);
+		return -EMSGSIZE;
+	}
+	return 0;
+}
+
+/**
+ * es58x_check_msg_len() - Check the size of a received message.
+ * @dev: Device, used to print error messages.
+ * @msg: Received message, must not be a pointer.
+ * @actual_len: Length of the message as advertised in the command header.
+ *
+ * Must be a macro in order to accept the different types of messages
+ * as an input. Can be use with any of the messages which have a fixed
+ * length. Check for an exact match of the size.
+ *
+ * Return: zero on success, -EMSGSIZE if @actual_len differs from the
+ * expected length.
+ */
+#define es58x_check_msg_len(dev, msg, actual_len)			\
+	__es58x_check_msg_len(dev, __stringify(msg),			\
+			      actual_len, sizeof(msg))
+
+static inline int __es58x_check_msg_max_len(const struct device *dev,
+					    const char *stringified_msg,
+					    size_t actual_len,
+					    size_t expected_len)
+{
+	if (actual_len > expected_len) {
+		dev_err(dev,
+			"Maximum length for %s is %zu but received command is %zu.\n",
+			stringified_msg, expected_len, actual_len);
+		return -EOVERFLOW;
+	}
+	return 0;
+}
+
+/**
+ * es58x_check_msg_max_len() - Check the maximum size of a received message.
+ * @dev: Device, used to print error messages.
+ * @msg: Received message, must not be a pointer.
+ * @actual_len: Length of the message as advertised in the command header.
+ *
+ * Must be a macro in order to accept the different types of messages
+ * as an input. To be used with the messages of variable sizes. Only
+ * check that the message is not bigger than the maximum expected
+ * size.
+ *
+ * Return: zero on success, -EOVERFLOW if @actual_len is greater than
+ * the expected length.
+ */
+#define es58x_check_msg_max_len(dev, msg, actual_len)			\
+	__es58x_check_msg_max_len(dev, __stringify(msg),		\
+				  actual_len, sizeof(msg))
+
+static inline int __es58x_msg_num_element(const struct device *dev,
+					  const char *stringified_msg,
+					  size_t actual_len, size_t msg_len,
+					  size_t elem_len)
+{
+	size_t actual_num_elem = actual_len / elem_len;
+	size_t expected_num_elem = msg_len / elem_len;
+
+	if (actual_num_elem == 0) {
+		dev_err(dev,
+			"Minimum length for %s is %zu but received command is %zu.\n",
+			stringified_msg, elem_len, actual_len);
+		return -EMSGSIZE;
+	} else if ((actual_len % elem_len) != 0) {
+		dev_err(dev,
+			"Received command length: %zu is not a multiple of %s[0]: %zu\n",
+			actual_len, stringified_msg, elem_len);
+		return -EMSGSIZE;
+	} else if (actual_num_elem > expected_num_elem) {
+		dev_err(dev,
+			"Array %s is supposed to have %zu elements each of size %zu...\n",
+			stringified_msg, expected_num_elem, elem_len);
+		dev_err(dev,
+			"... But received command has %zu elements (total length %zu).\n",
+			actual_num_elem, actual_len);
+		return -EOVERFLOW;
+	}
+	return actual_num_elem;
+}
+
+/**
+ * es58x_msg_num_element() - Check size and give the number of
+ *	elements in a message of array type.
+ * @dev: Device, used to print error messages.
+ * @msg: Received message, must be an array.
+ * @actual_len: Length of the message as advertised in the command
+ *	header.
+ *
+ * Must be a macro in order to accept the different types of messages
+ * as an input. To be used on message of array type. Array's element
+ * has to be of fixed size (else use es58x_check_msg_max_len()). Check
+ * that the total length is an exact multiple of the length of a
+ * single element.
+ *
+ * Return: number of elements in the array on success, -EOVERFLOW if
+ * @actual_len is greater than the expected length, -EMSGSIZE if
+ * @actual_len is not a multiple of a single element.
+ */
+#define es58x_msg_num_element(dev, msg, actual_len)			\
+({									\
+	size_t __elem_len = sizeof((msg)[0]) + __must_be_array(msg);	\
+	__es58x_msg_num_element(dev, __stringify(msg), actual_len,	\
+				sizeof(msg), __elem_len);		\
+})
+
+/**
+ * es58x_priv() - Get the priv member and cast it to struct es58x_priv.
+ * @netdev: CAN network device.
+ *
+ * Return: ES58X device.
+ */
+static inline struct es58x_priv *es58x_priv(struct net_device *netdev)
+{
+	return (struct es58x_priv *)netdev_priv(netdev);
+}
+
+/**
+ * ES58X_SIZEOF_URB_CMD() - Calculate the maximum length of an urb
+ *	command for a given message field name.
+ * @es58x_urb_cmd_type: type (either "struct es581_4_urb_cmd" or
+ *	"struct es58x_fd_urb_cmd").
+ * @msg_field: name of the message field.
+ *
+ * Must be a macro in order to accept the different command types as
+ * an input.
+ *
+ * Return: length of the urb command.
+ */
+#define ES58X_SIZEOF_URB_CMD(es58x_urb_cmd_type, msg_field)		\
+	(offsetof(es58x_urb_cmd_type, raw_msg)				\
+		+ sizeof_field(es58x_urb_cmd_type, msg_field)		\
+		+ sizeof_field(es58x_urb_cmd_type,			\
+			       reserved_for_crc16_do_not_use))
+
+/**
+ * es58x_get_urb_cmd_len() - Calculate the actual length of an urb
+ *	command for a given message length.
+ * @es58x_dev: ES58X device.
+ * @msg_len: Length of the message.
+ *
+ * Add the header and CRC lengths to the message length.
+ *
+ * Return: length of the urb command.
+ */
+static inline size_t es58x_get_urb_cmd_len(struct es58x_device *es58x_dev,
+					   u16 msg_len)
+{
+	return es58x_dev->param->urb_cmd_header_len + msg_len + sizeof(u16);
+}
+
+/**
+ * es58x_get_netdev() - Get the network device.
+ * @es58x_dev: ES58X device.
+ * @channel_no: The channel number as advertised in the urb command.
+ * @channel_idx_offset: Some of the ES58x starts channel numbering
+ *	from 0 (ES58X FD), others from 1 (ES581.4).
+ * @netdev: CAN network device.
+ *
+ * Do a sanity check on the index provided by the device.
+ *
+ * Return: zero on success, -ECHRNG if the received channel number is
+ *	out of range and -ENODEV if the network device is not yet
+ *	configured.
+ */
+static inline int es58x_get_netdev(struct es58x_device *es58x_dev,
+				   int channel_no, int channel_idx_offset,
+				   struct net_device **netdev)
+{
+	int channel_idx = channel_no - channel_idx_offset;
+
+	*netdev = NULL;
+	if (channel_idx < 0 || channel_idx >= es58x_dev->num_can_ch)
+		return -ECHRNG;
+
+	*netdev = es58x_dev->netdev[channel_idx];
+	if (!netdev || !netif_device_present(*netdev))
+		return -ENODEV;
+
+	return 0;
+}
+
+/**
+ * es58x_get_raw_can_id() - Get the CAN ID.
+ * @cf: CAN frame.
+ *
+ * Mask the CAN ID in order to only keep the significant bits.
+ *
+ * Return: the raw value of the CAN ID.
+ */
+static inline int es58x_get_raw_can_id(const struct can_frame *cf)
+{
+	if (cf->can_id & CAN_EFF_FLAG)
+		return cf->can_id & CAN_EFF_MASK;
+	else
+		return cf->can_id & CAN_SFF_MASK;
+}
+
+/**
+ * es58x_get_flags() - Get the CAN flags.
+ * @skb: socket buffer of a CAN message.
+ *
+ * Return: the CAN flag as an enum es58x_flag.
+ */
+static inline enum es58x_flag es58x_get_flags(const struct sk_buff *skb)
+{
+	struct canfd_frame *cf = (struct canfd_frame *)skb->data;
+	enum es58x_flag es58x_flags = 0;
+
+	if (cf->can_id & CAN_EFF_FLAG)
+		es58x_flags |= ES58X_FLAG_EFF;
+
+	if (can_is_canfd_skb(skb)) {
+		es58x_flags |= ES58X_FLAG_FD_DATA;
+		if (cf->flags & CANFD_BRS)
+			es58x_flags |= ES58X_FLAG_FD_BRS;
+		if (cf->flags & CANFD_ESI)
+			es58x_flags |= ES58X_FLAG_FD_ESI;
+	} else if (cf->can_id & CAN_RTR_FLAG)
+		/* Remote frames are only defined in Classical CAN frames */
+		es58x_flags |= ES58X_FLAG_RTR;
+
+	return es58x_flags;
+}
+
+int es58x_can_get_echo_skb(struct net_device *netdev, u32 packet_idx,
+			   u64 *tstamps, unsigned int pkts);
+int es58x_tx_ack_msg(struct net_device *netdev, u16 tx_free_entries,
+		     enum es58x_ret_u32 rx_cmd_ret_u32);
+int es58x_rx_can_msg(struct net_device *netdev, u64 timestamp, const u8 *data,
+		     canid_t can_id, enum es58x_flag es58x_flags, u8 dlc);
+int es58x_rx_err_msg(struct net_device *netdev, enum es58x_err error,
+		     enum es58x_event event, u64 timestamp);
+void es58x_rx_timestamp(struct es58x_device *es58x_dev, u64 timestamp);
+int es58x_rx_cmd_ret_u8(struct device *dev, enum es58x_ret_type cmd_ret_type,
+			enum es58x_ret_u8 rx_cmd_ret_u8);
+int es58x_rx_cmd_ret_u32(struct net_device *netdev,
+			 enum es58x_ret_type cmd_ret_type,
+			 enum es58x_ret_u32 rx_cmd_ret_u32);
+int es58x_send_msg(struct es58x_device *es58x_dev, u8 cmd_type, u8 cmd_id,
+		   const void *msg, u16 cmd_len, int channel_idx);
+
+extern const struct es58x_parameters es581_4_param;
+extern const struct es58x_operators es581_4_ops;
+
+extern const struct es58x_parameters es58x_fd_param;
+extern const struct es58x_operators es58x_fd_ops;
+
+#endif /* __ES58X_COMMON_H__ */

drivers/net/can/usb/etas_es58x/es58x_fd.c

+// SPDX-License-Identifier: GPL-2.0
+
+/* Driver for ETAS GmbH ES58X USB CAN(-FD) Bus Interfaces.
+ *
+ * File es58x_fd.c: Adds support to ETAS ES582.1 and ES584.1 (naming
+ * convention: we use the term "ES58X FD" when referring to those two
+ * variants together).
+ *
+ * Copyright (c) 2019 Robert Bosch Engineering and Business Solutions. All rights reserved.
+ * Copyright (c) 2020 ETAS K.K.. All rights reserved.
+ * Copyright (c) 2020, 2021 Vincent Mailhol <mailhol.vincent@wanadoo.fr>
+ */
+
+#include <linux/kernel.h>
+#include <asm/unaligned.h>
+
+#include "es58x_core.h"
+#include "es58x_fd.h"
+
+/**
+ * es58x_fd_sizeof_rx_tx_msg() - Calculate the actual length of the
+ *	structure of a rx or tx message.
+ * @msg: message of variable length, must have a dlc and a len fields.
+ *
+ * Even if RTR frames have actually no payload, the ES58X devices
+ * still expect it. Must be a macro in order to accept several types
+ * (struct es58x_fd_tx_can_msg and struct es58x_fd_rx_can_msg) as an
+ * input.
+ *
+ * Return: length of the message.
+ */
+#define es58x_fd_sizeof_rx_tx_msg(msg)					\
+({									\
+	typeof(msg) __msg = (msg);					\
+	size_t __msg_len;						\
+									\
+	if (__msg.flags & ES58X_FLAG_FD_DATA)				\
+		__msg_len = canfd_sanitize_len(__msg.len);		\
+	else								\
+		__msg_len = can_cc_dlc2len(__msg.dlc);			\
+									\
+	offsetof(typeof(__msg), data[__msg_len]);			\
+})
+
+static enum es58x_fd_cmd_type es58x_fd_cmd_type(struct net_device *netdev)
+{
+	u32 ctrlmode = es58x_priv(netdev)->can.ctrlmode;
+
+	if (ctrlmode & (CAN_CTRLMODE_FD | CAN_CTRLMODE_FD_NON_ISO))
+		return ES58X_FD_CMD_TYPE_CANFD;
+	else
+		return ES58X_FD_CMD_TYPE_CAN;
+}
+
+static u16 es58x_fd_get_msg_len(const union es58x_urb_cmd *urb_cmd)
+{
+	return get_unaligned_le16(&urb_cmd->es58x_fd_urb_cmd.msg_len);
+}
+
+static int es58x_fd_echo_msg(struct net_device *netdev,
+			     const struct es58x_fd_urb_cmd *es58x_fd_urb_cmd)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	const struct es58x_fd_echo_msg *echo_msg;
+	struct es58x_device *es58x_dev = priv->es58x_dev;
+	u64 *tstamps = es58x_dev->timestamps;
+	u16 msg_len = get_unaligned_le16(&es58x_fd_urb_cmd->msg_len);
+	int i, num_element;
+	u32 rcv_packet_idx;
+
+	const u32 mask = GENMASK(31, sizeof(echo_msg->packet_idx) * 8);
+
+	num_element = es58x_msg_num_element(es58x_dev->dev,
+					    es58x_fd_urb_cmd->echo_msg,
+					    msg_len);
+	if (num_element < 0)
+		return num_element;
+	echo_msg = es58x_fd_urb_cmd->echo_msg;
+
+	rcv_packet_idx = (priv->tx_tail & mask) | echo_msg[0].packet_idx;
+	for (i = 0; i < num_element; i++) {
+		if ((u8)rcv_packet_idx != echo_msg[i].packet_idx) {
+			netdev_err(netdev, "Packet idx jumped from %u to %u\n",
+				   (u8)rcv_packet_idx - 1,
+				   echo_msg[i].packet_idx);
+			return -EBADMSG;
+		}
+
+		tstamps[i] = get_unaligned_le64(&echo_msg[i].timestamp);
+		rcv_packet_idx++;
+	}
+
+	return es58x_can_get_echo_skb(netdev, priv->tx_tail, tstamps, num_element);
+}
+
+static int es58x_fd_rx_can_msg(struct net_device *netdev,
+			       const struct es58x_fd_urb_cmd *es58x_fd_urb_cmd)
+{
+	struct es58x_device *es58x_dev = es58x_priv(netdev)->es58x_dev;
+	const u8 *rx_can_msg_buf = es58x_fd_urb_cmd->rx_can_msg_buf;
+	u16 rx_can_msg_buf_len = get_unaligned_le16(&es58x_fd_urb_cmd->msg_len);
+	int pkts, ret;
+
+	ret = es58x_check_msg_max_len(es58x_dev->dev,
+				      es58x_fd_urb_cmd->rx_can_msg_buf,
+				      rx_can_msg_buf_len);
+	if (ret)
+		return ret;
+
+	for (pkts = 0; rx_can_msg_buf_len > 0; pkts++) {
+		const struct es58x_fd_rx_can_msg *rx_can_msg =
+		    (const struct es58x_fd_rx_can_msg *)rx_can_msg_buf;
+		bool is_can_fd = !!(rx_can_msg->flags & ES58X_FLAG_FD_DATA);
+		/* rx_can_msg_len is the length of the rx_can_msg
+		 * buffer. Not to be confused with rx_can_msg->len
+		 * which is the length of the CAN payload
+		 * rx_can_msg->data.
+		 */
+		u16 rx_can_msg_len = es58x_fd_sizeof_rx_tx_msg(*rx_can_msg);
+
+		if (rx_can_msg_len > rx_can_msg_buf_len) {
+			netdev_err(netdev,
+				   "%s: Expected a rx_can_msg of size %d but only %d bytes are left in rx_can_msg_buf\n",
+				   __func__,
+				   rx_can_msg_len, rx_can_msg_buf_len);
+			return -EMSGSIZE;
+		}
+		if (rx_can_msg->len > CANFD_MAX_DLEN) {
+			netdev_err(netdev,
+				   "%s: Data length is %d but maximum should be %d\n",
+				   __func__, rx_can_msg->len, CANFD_MAX_DLEN);
+			return -EMSGSIZE;
+		}
+
+		if (netif_running(netdev)) {
+			u64 tstamp = get_unaligned_le64(&rx_can_msg->timestamp);
+			canid_t can_id = get_unaligned_le32(&rx_can_msg->can_id);
+			u8 dlc;
+
+			if (is_can_fd)
+				dlc = can_fd_len2dlc(rx_can_msg->len);
+			else
+				dlc = rx_can_msg->dlc;
+
+			ret = es58x_rx_can_msg(netdev, tstamp, rx_can_msg->data,
+					       can_id, rx_can_msg->flags, dlc);
+			if (ret)
+				break;
+		}
+
+		rx_can_msg_buf_len -= rx_can_msg_len;
+		rx_can_msg_buf += rx_can_msg_len;
+	}
+
+	if (!netif_running(netdev)) {
+		if (net_ratelimit())
+			netdev_info(netdev,
+				    "%s: %s is down, dropping %d rx packets\n",
+				    __func__, netdev->name, pkts);
+		netdev->stats.rx_dropped += pkts;
+	}
+
+	return ret;
+}
+
+static int es58x_fd_rx_event_msg(struct net_device *netdev,
+				 const struct es58x_fd_urb_cmd *es58x_fd_urb_cmd)
+{
+	struct es58x_device *es58x_dev = es58x_priv(netdev)->es58x_dev;
+	u16 msg_len = get_unaligned_le16(&es58x_fd_urb_cmd->msg_len);
+	const struct es58x_fd_rx_event_msg *rx_event_msg;
+	int ret;
+
+	ret = es58x_check_msg_len(es58x_dev->dev, *rx_event_msg, msg_len);
+	if (ret)
+		return ret;
+
+	rx_event_msg = &es58x_fd_urb_cmd->rx_event_msg;
+
+	return es58x_rx_err_msg(netdev, rx_event_msg->error_code,
+				rx_event_msg->event_code,
+				get_unaligned_le64(&rx_event_msg->timestamp));
+}
+
+static int es58x_fd_rx_cmd_ret_u32(struct net_device *netdev,
+				   const struct es58x_fd_urb_cmd *es58x_fd_urb_cmd,
+				   enum es58x_ret_type cmd_ret_type)
+{
+	struct es58x_device *es58x_dev = es58x_priv(netdev)->es58x_dev;
+	u16 msg_len = get_unaligned_le16(&es58x_fd_urb_cmd->msg_len);
+	int ret;
+
+	ret = es58x_check_msg_len(es58x_dev->dev,
+				  es58x_fd_urb_cmd->rx_cmd_ret_le32, msg_len);
+	if (ret)
+		return ret;
+
+	return es58x_rx_cmd_ret_u32(netdev, cmd_ret_type,
+				    get_unaligned_le32(&es58x_fd_urb_cmd->rx_cmd_ret_le32));
+}
+
+static int es58x_fd_tx_ack_msg(struct net_device *netdev,
+			       const struct es58x_fd_urb_cmd *es58x_fd_urb_cmd)
+{
+	struct es58x_device *es58x_dev = es58x_priv(netdev)->es58x_dev;
+	const struct es58x_fd_tx_ack_msg *tx_ack_msg;
+	u16 msg_len = get_unaligned_le16(&es58x_fd_urb_cmd->msg_len);
+	int ret;
+
+	tx_ack_msg = &es58x_fd_urb_cmd->tx_ack_msg;
+	ret = es58x_check_msg_len(es58x_dev->dev, *tx_ack_msg, msg_len);
+	if (ret)
+		return ret;
+
+	return es58x_tx_ack_msg(netdev,
+				get_unaligned_le16(&tx_ack_msg->tx_free_entries),
+				get_unaligned_le32(&tx_ack_msg->rx_cmd_ret_le32));
+}
+
+static int es58x_fd_can_cmd_id(struct es58x_device *es58x_dev,
+			       const struct es58x_fd_urb_cmd *es58x_fd_urb_cmd)
+{
+	struct net_device *netdev;
+	int ret;
+
+	ret = es58x_get_netdev(es58x_dev, es58x_fd_urb_cmd->channel_idx,
+			       ES58X_FD_CHANNEL_IDX_OFFSET, &netdev);
+	if (ret)
+		return ret;
+
+	switch ((enum es58x_fd_can_cmd_id)es58x_fd_urb_cmd->cmd_id) {
+	case ES58X_FD_CAN_CMD_ID_ENABLE_CHANNEL:
+		return es58x_fd_rx_cmd_ret_u32(netdev, es58x_fd_urb_cmd,
+					       ES58X_RET_TYPE_ENABLE_CHANNEL);
+
+	case ES58X_FD_CAN_CMD_ID_DISABLE_CHANNEL:
+		return es58x_fd_rx_cmd_ret_u32(netdev, es58x_fd_urb_cmd,
+					       ES58X_RET_TYPE_DISABLE_CHANNEL);
+
+	case ES58X_FD_CAN_CMD_ID_TX_MSG:
+		return es58x_fd_tx_ack_msg(netdev, es58x_fd_urb_cmd);
+
+	case ES58X_FD_CAN_CMD_ID_ECHO_MSG:
+		return es58x_fd_echo_msg(netdev, es58x_fd_urb_cmd);
+
+	case ES58X_FD_CAN_CMD_ID_RX_MSG:
+		return es58x_fd_rx_can_msg(netdev, es58x_fd_urb_cmd);
+
+	case ES58X_FD_CAN_CMD_ID_RESET_RX:
+		return es58x_fd_rx_cmd_ret_u32(netdev, es58x_fd_urb_cmd,
+					       ES58X_RET_TYPE_RESET_RX);
+
+	case ES58X_FD_CAN_CMD_ID_RESET_TX:
+		return es58x_fd_rx_cmd_ret_u32(netdev, es58x_fd_urb_cmd,
+					       ES58X_RET_TYPE_RESET_TX);
+
+	case ES58X_FD_CAN_CMD_ID_ERROR_OR_EVENT_MSG:
+		return es58x_fd_rx_event_msg(netdev, es58x_fd_urb_cmd);
+
+	default:
+		return -EBADRQC;
+	}
+}
+
+static int es58x_fd_device_cmd_id(struct es58x_device *es58x_dev,
+				  const struct es58x_fd_urb_cmd *es58x_fd_urb_cmd)
+{
+	u16 msg_len = get_unaligned_le16(&es58x_fd_urb_cmd->msg_len);
+	int ret;
+
+	switch ((enum es58x_fd_dev_cmd_id)es58x_fd_urb_cmd->cmd_id) {
+	case ES58X_FD_DEV_CMD_ID_TIMESTAMP:
+		ret = es58x_check_msg_len(es58x_dev->dev,
+					  es58x_fd_urb_cmd->timestamp, msg_len);
+		if (ret)
+			return ret;
+		es58x_rx_timestamp(es58x_dev,
+				   get_unaligned_le64(&es58x_fd_urb_cmd->timestamp));
+		return 0;
+
+	default:
+		return -EBADRQC;
+	}
+}
+
+static int es58x_fd_handle_urb_cmd(struct es58x_device *es58x_dev,
+				   const union es58x_urb_cmd *urb_cmd)
+{
+	const struct es58x_fd_urb_cmd *es58x_fd_urb_cmd;
+	int ret;
+
+	es58x_fd_urb_cmd = &urb_cmd->es58x_fd_urb_cmd;
+
+	switch ((enum es58x_fd_cmd_type)es58x_fd_urb_cmd->cmd_type) {
+	case ES58X_FD_CMD_TYPE_CAN:
+	case ES58X_FD_CMD_TYPE_CANFD:
+		ret = es58x_fd_can_cmd_id(es58x_dev, es58x_fd_urb_cmd);
+		break;
+
+	case ES58X_FD_CMD_TYPE_DEVICE:
+		ret = es58x_fd_device_cmd_id(es58x_dev, es58x_fd_urb_cmd);
+		break;
+
+	default:
+		ret = -EBADRQC;
+		break;
+	}
+
+	if (ret == -EBADRQC)
+		dev_err(es58x_dev->dev,
+			"%s: Unknown command type (0x%02X) and command ID (0x%02X) combination\n",
+			__func__, es58x_fd_urb_cmd->cmd_type,
+			es58x_fd_urb_cmd->cmd_id);
+
+	return ret;
+}
+
+static void es58x_fd_fill_urb_header(union es58x_urb_cmd *urb_cmd, u8 cmd_type,
+				     u8 cmd_id, u8 channel_idx, u16 msg_len)
+{
+	struct es58x_fd_urb_cmd *es58x_fd_urb_cmd = &urb_cmd->es58x_fd_urb_cmd;
+
+	es58x_fd_urb_cmd->SOF = cpu_to_le16(es58x_fd_param.tx_start_of_frame);
+	es58x_fd_urb_cmd->cmd_type = cmd_type;
+	es58x_fd_urb_cmd->cmd_id = cmd_id;
+	es58x_fd_urb_cmd->channel_idx = channel_idx;
+	es58x_fd_urb_cmd->msg_len = cpu_to_le16(msg_len);
+}
+
+static int es58x_fd_tx_can_msg(struct es58x_priv *priv,
+			       const struct sk_buff *skb)
+{
+	struct es58x_device *es58x_dev = priv->es58x_dev;
+	union es58x_urb_cmd *urb_cmd = priv->tx_urb->transfer_buffer;
+	struct es58x_fd_urb_cmd *es58x_fd_urb_cmd = &urb_cmd->es58x_fd_urb_cmd;
+	struct can_frame *cf = (struct can_frame *)skb->data;
+	struct es58x_fd_tx_can_msg *tx_can_msg;
+	bool is_fd = can_is_canfd_skb(skb);
+	u16 msg_len;
+	int ret;
+
+	if (priv->tx_can_msg_cnt == 0) {
+		msg_len = 0;
+		es58x_fd_fill_urb_header(urb_cmd,
+					 is_fd ? ES58X_FD_CMD_TYPE_CANFD
+					       : ES58X_FD_CMD_TYPE_CAN,
+					 ES58X_FD_CAN_CMD_ID_TX_MSG_NO_ACK,
+					 priv->channel_idx, msg_len);
+	} else {
+		msg_len = es58x_fd_get_msg_len(urb_cmd);
+	}
+
+	ret = es58x_check_msg_max_len(es58x_dev->dev,
+				      es58x_fd_urb_cmd->tx_can_msg_buf,
+				      msg_len + sizeof(*tx_can_msg));
+	if (ret)
+		return ret;
+
+	/* Fill message contents. */
+	tx_can_msg = (struct es58x_fd_tx_can_msg *)
+	    &es58x_fd_urb_cmd->tx_can_msg_buf[msg_len];
+	tx_can_msg->packet_idx = (u8)priv->tx_head;
+	put_unaligned_le32(es58x_get_raw_can_id(cf), &tx_can_msg->can_id);
+	tx_can_msg->flags = (u8)es58x_get_flags(skb);
+	if (is_fd)
+		tx_can_msg->len = cf->len;
+	else
+		tx_can_msg->dlc = can_get_cc_dlc(cf, priv->can.ctrlmode);
+	memcpy(tx_can_msg->data, cf->data, cf->len);
+
+	/* Calculate new sizes */
+	msg_len += es58x_fd_sizeof_rx_tx_msg(*tx_can_msg);
+	priv->tx_urb->transfer_buffer_length = es58x_get_urb_cmd_len(es58x_dev,
+								     msg_len);
+	put_unaligned_le16(msg_len, &es58x_fd_urb_cmd->msg_len);
+
+	return 0;
+}
+
+static void es58x_fd_convert_bittiming(struct es58x_fd_bittiming *es58x_fd_bt,
+				       struct can_bittiming *bt)
+{
+	/* The actual value set in the hardware registers is one less
+	 * than the functional value.
+	 */
+	const int offset = 1;
+
+	es58x_fd_bt->bitrate = cpu_to_le32(bt->bitrate);
+	es58x_fd_bt->tseg1 =
+	    cpu_to_le16(bt->prop_seg + bt->phase_seg1 - offset);
+	es58x_fd_bt->tseg2 = cpu_to_le16(bt->phase_seg2 - offset);
+	es58x_fd_bt->brp = cpu_to_le16(bt->brp - offset);
+	es58x_fd_bt->sjw = cpu_to_le16(bt->sjw - offset);
+}
+
+static int es58x_fd_enable_channel(struct es58x_priv *priv)
+{
+	struct es58x_device *es58x_dev = priv->es58x_dev;
+	struct net_device *netdev = es58x_dev->netdev[priv->channel_idx];
+	struct es58x_fd_tx_conf_msg tx_conf_msg = { 0 };
+	u32 ctrlmode;
+	size_t conf_len = 0;
+
+	es58x_fd_convert_bittiming(&tx_conf_msg.nominal_bittiming,
+				   &priv->can.bittiming);
+	ctrlmode = priv->can.ctrlmode;
+
+	if (ctrlmode & CAN_CTRLMODE_3_SAMPLES)
+		tx_conf_msg.samples_per_bit = ES58X_SAMPLES_PER_BIT_THREE;
+	else
+		tx_conf_msg.samples_per_bit = ES58X_SAMPLES_PER_BIT_ONE;
+	tx_conf_msg.sync_edge = ES58X_SYNC_EDGE_SINGLE;
+	tx_conf_msg.physical_layer = ES58X_PHYSICAL_LAYER_HIGH_SPEED;
+	tx_conf_msg.echo_mode = ES58X_ECHO_ON;
+	if (ctrlmode & CAN_CTRLMODE_LISTENONLY)
+		tx_conf_msg.ctrlmode |= ES58X_FD_CTRLMODE_PASSIVE;
+	else
+		tx_conf_msg.ctrlmode |=  ES58X_FD_CTRLMODE_ACTIVE;
+
+	if (ctrlmode & CAN_CTRLMODE_FD_NON_ISO) {
+		tx_conf_msg.ctrlmode |= ES58X_FD_CTRLMODE_FD_NON_ISO;
+		tx_conf_msg.canfd_enabled = 1;
+	} else if (ctrlmode & CAN_CTRLMODE_FD) {
+		tx_conf_msg.ctrlmode |= ES58X_FD_CTRLMODE_FD;
+		tx_conf_msg.canfd_enabled = 1;
+	}
+
+	if (tx_conf_msg.canfd_enabled) {
+		es58x_fd_convert_bittiming(&tx_conf_msg.data_bittiming,
+					   &priv->can.data_bittiming);
+
+		if (priv->can.tdc.tdco) {
+			tx_conf_msg.tdc_enabled = 1;
+			tx_conf_msg.tdco = cpu_to_le16(priv->can.tdc.tdco);
+			tx_conf_msg.tdcf = cpu_to_le16(priv->can.tdc.tdcf);
+		}
+
+		conf_len = ES58X_FD_CANFD_CONF_LEN;
+	} else {
+		conf_len = ES58X_FD_CAN_CONF_LEN;
+	}
+
+	return es58x_send_msg(es58x_dev, es58x_fd_cmd_type(netdev),
+			      ES58X_FD_CAN_CMD_ID_ENABLE_CHANNEL,
+			      &tx_conf_msg, conf_len, priv->channel_idx);
+}
+
+static int es58x_fd_disable_channel(struct es58x_priv *priv)
+{
+	/* The type (ES58X_FD_CMD_TYPE_CAN or ES58X_FD_CMD_TYPE_CANFD) does
+	 * not matter here.
+	 */
+	return es58x_send_msg(priv->es58x_dev, ES58X_FD_CMD_TYPE_CAN,
+			      ES58X_FD_CAN_CMD_ID_DISABLE_CHANNEL,
+			      ES58X_EMPTY_MSG, 0, priv->channel_idx);
+}
+
+static int es58x_fd_get_timestamp(struct es58x_device *es58x_dev)
+{
+	return es58x_send_msg(es58x_dev, ES58X_FD_CMD_TYPE_DEVICE,
+			      ES58X_FD_DEV_CMD_ID_TIMESTAMP, ES58X_EMPTY_MSG,
+			      0, ES58X_CHANNEL_IDX_NA);
+}
+
+/* Nominal bittiming constants for ES582.1 and ES584.1 as specified in
+ * the microcontroller datasheet: "SAM E701/S70/V70/V71 Family"
+ * section 49.6.8 "MCAN Nominal Bit Timing and Prescaler Register"
+ * from Microchip.
+ *
+ * The values from the specification are the hardware register
+ * values. To convert them to the functional values, all ranges were
+ * incremented by 1 (e.g. range [0..n-1] changed to [1..n]).
+ */
+static const struct can_bittiming_const es58x_fd_nom_bittiming_const = {
+	.name = "ES582.1/ES584.1",
+	.tseg1_min = 2,
+	.tseg1_max = 256,
+	.tseg2_min = 2,
+	.tseg2_max = 128,
+	.sjw_max = 128,
+	.brp_min = 1,
+	.brp_max = 512,
+	.brp_inc = 1
+};
+
+/* Data bittiming constants for ES582.1 and ES584.1 as specified in
+ * the microcontroller datasheet: "SAM E701/S70/V70/V71 Family"
+ * section 49.6.4 "MCAN Data Bit Timing and Prescaler Register" from
+ * Microchip.
+ */
+static const struct can_bittiming_const es58x_fd_data_bittiming_const = {
+	.name = "ES582.1/ES584.1",
+	.tseg1_min = 2,
+	.tseg1_max = 32,
+	.tseg2_min = 1,
+	.tseg2_max = 16,
+	.sjw_max = 8,
+	.brp_min = 1,
+	.brp_max = 32,
+	.brp_inc = 1
+};
+
+/* Transmission Delay Compensation constants for ES582.1 and ES584.1
+ * as specified in the microcontroller datasheet: "SAM
+ * E701/S70/V70/V71 Family" section 49.6.15 "MCAN Transmitter Delay
+ * Compensation Register" from Microchip.
+ */
+static const struct can_tdc_const es58x_tdc_const = {
+	.tdcv_max = 0, /* Manual mode not supported. */
+	.tdco_max = 127,
+	.tdcf_max = 127
+};
+
+const struct es58x_parameters es58x_fd_param = {
+	.bittiming_const = &es58x_fd_nom_bittiming_const,
+	.data_bittiming_const = &es58x_fd_data_bittiming_const,
+	.tdc_const = &es58x_tdc_const,
+	/* The devices use NXP TJA1044G transievers which guarantee
+	 * the timing for data rates up to 5 Mbps. Bitrates up to 8
+	 * Mbps work in an optimal environment but are not recommended
+	 * for production environment.
+	 */
+	.bitrate_max = 8 * CAN_MBPS,
+	.clock = {.freq = 80 * CAN_MHZ},
+	.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK | CAN_CTRLMODE_LISTENONLY |
+	    CAN_CTRLMODE_3_SAMPLES | CAN_CTRLMODE_FD | CAN_CTRLMODE_FD_NON_ISO |
+	    CAN_CTRLMODE_CC_LEN8_DLC,
+	.tx_start_of_frame = 0xCEFA,	/* FACE in little endian */
+	.rx_start_of_frame = 0xFECA,	/* CAFE in little endian */
+	.tx_urb_cmd_max_len = ES58X_FD_TX_URB_CMD_MAX_LEN,
+	.rx_urb_cmd_max_len = ES58X_FD_RX_URB_CMD_MAX_LEN,
+	/* Size of internal device TX queue is 500.
+	 *
+	 * However, when reaching value around 278, the device's busy
+	 * LED turns on and thus maximum value of 500 is never reached
+	 * in practice. Also, when this value is too high, some error
+	 * on the echo_msg were witnessed when the device is
+	 * recovering from bus off.
+	 *
+	 * For above reasons, a value that would prevent the device
+	 * from becoming busy was chosen. In practice, BQL would
+	 * prevent the value from even getting closer to below
+	 * maximum, so no impact on performance was measured.
+	 */
+	.fifo_mask = 255, /* echo_skb_max = 256 */
+	.dql_min_limit = CAN_FRAME_LEN_MAX * 15, /* Empirical value. */
+	.tx_bulk_max = ES58X_FD_TX_BULK_MAX,
+	.urb_cmd_header_len = ES58X_FD_URB_CMD_HEADER_LEN,
+	.rx_urb_max = ES58X_RX_URBS_MAX,
+	.tx_urb_max = ES58X_TX_URBS_MAX
+};
+
+const struct es58x_operators es58x_fd_ops = {
+	.get_msg_len = es58x_fd_get_msg_len,
+	.handle_urb_cmd = es58x_fd_handle_urb_cmd,
+	.fill_urb_header = es58x_fd_fill_urb_header,
+	.tx_can_msg = es58x_fd_tx_can_msg,
+	.enable_channel = es58x_fd_enable_channel,
+	.disable_channel = es58x_fd_disable_channel,
+	.reset_device = NULL, /* Not implemented in the device firmware. */
+	.get_timestamp = es58x_fd_get_timestamp
+};

drivers/net/can/usb/etas_es58x/es58x_fd.h

+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* Driver for ETAS GmbH ES58X USB CAN(-FD) Bus Interfaces.
+ *
+ * File es58x_fd.h: Definitions and declarations specific to ETAS
+ * ES582.1 and ES584.1 (naming convention: we use the term "ES58X FD"
+ * when referring to those two variants together).
+ *
+ * Copyright (c) 2019 Robert Bosch Engineering and Business Solutions. All rights reserved.
+ * Copyright (c) 2020 ETAS K.K.. All rights reserved.
+ * Copyright (c) 2020, 2021 Vincent Mailhol <mailhol.vincent@wanadoo.fr>
+ */
+
+#ifndef __ES58X_FD_H__
+#define __ES58X_FD_H__
+
+#include <linux/types.h>
+
+#define ES582_1_NUM_CAN_CH 2
+#define ES584_1_NUM_CAN_CH 1
+#define ES58X_FD_NUM_CAN_CH 2
+#define ES58X_FD_CHANNEL_IDX_OFFSET 0
+
+#define ES58X_FD_TX_BULK_MAX 100
+#define ES58X_FD_RX_BULK_MAX 100
+#define ES58X_FD_ECHO_BULK_MAX 100
+
+enum es58x_fd_cmd_type {
+	ES58X_FD_CMD_TYPE_CAN = 0x03,
+	ES58X_FD_CMD_TYPE_CANFD = 0x04,
+	ES58X_FD_CMD_TYPE_DEVICE = 0xFF
+};
+
+/* Command IDs for ES58X_FD_CMD_TYPE_{CAN,CANFD}. */
+enum es58x_fd_can_cmd_id {
+	ES58X_FD_CAN_CMD_ID_ENABLE_CHANNEL = 0x01,
+	ES58X_FD_CAN_CMD_ID_DISABLE_CHANNEL = 0x02,
+	ES58X_FD_CAN_CMD_ID_TX_MSG = 0x05,
+	ES58X_FD_CAN_CMD_ID_ECHO_MSG = 0x07,
+	ES58X_FD_CAN_CMD_ID_RX_MSG = 0x10,
+	ES58X_FD_CAN_CMD_ID_ERROR_OR_EVENT_MSG = 0x11,
+	ES58X_FD_CAN_CMD_ID_RESET_RX = 0x20,
+	ES58X_FD_CAN_CMD_ID_RESET_TX = 0x21,
+	ES58X_FD_CAN_CMD_ID_TX_MSG_NO_ACK = 0x55
+};
+
+/* Command IDs for ES58X_FD_CMD_TYPE_DEVICE. */
+enum es58x_fd_dev_cmd_id {
+	ES58X_FD_DEV_CMD_ID_GETTIMETICKS = 0x01,
+	ES58X_FD_DEV_CMD_ID_TIMESTAMP = 0x02
+};
+
+/**
+ * enum es58x_fd_ctrlmode - Controller mode.
+ * @ES58X_FD_CTRLMODE_ACTIVE: send and receive messages.
+ * @ES58X_FD_CTRLMODE_PASSIVE: only receive messages (monitor). Do not
+ *	send anything, not even the acknowledgment bit.
+ * @ES58X_FD_CTRLMODE_FD: CAN FD according to ISO11898-1.
+ * @ES58X_FD_CTRLMODE_FD_NON_ISO: follow Bosch CAN FD Specification
+ *	V1.0
+ * @ES58X_FD_CTRLMODE_DISABLE_PROTOCOL_EXCEPTION_HANDLING: How to
+ *	behave when CAN FD reserved bit is monitored as
+ *	dominant. (c.f. ISO 11898-1:2015, section 10.4.2.4 "Control
+ *	field", paragraph "r0 bit"). 0 (not disable = enable): send
+ *	error frame. 1 (disable): goes into bus integration mode
+ *	(c.f. below).
+ * @ES58X_FD_CTRLMODE_EDGE_FILTER_DURING_BUS_INTEGRATION: 0: Edge
+ *	filtering is disabled. 1: Edge filtering is enabled. Two
+ *	consecutive dominant bits required to detect an edge for hard
+ *	synchronization.
+ */
+enum es58x_fd_ctrlmode {
+	ES58X_FD_CTRLMODE_ACTIVE = 0,
+	ES58X_FD_CTRLMODE_PASSIVE = BIT(0),
+	ES58X_FD_CTRLMODE_FD = BIT(4),
+	ES58X_FD_CTRLMODE_FD_NON_ISO = BIT(5),
+	ES58X_FD_CTRLMODE_DISABLE_PROTOCOL_EXCEPTION_HANDLING = BIT(6),
+	ES58X_FD_CTRLMODE_EDGE_FILTER_DURING_BUS_INTEGRATION = BIT(7)
+};
+
+struct es58x_fd_bittiming {
+	__le32 bitrate;
+	__le16 tseg1;		/* range: [tseg1_min-1..tseg1_max-1] */
+	__le16 tseg2;		/* range: [tseg2_min-1..tseg2_max-1] */
+	__le16 brp;		/* range: [brp_min-1..brp_max-1] */
+	__le16 sjw;		/* range: [0..sjw_max-1] */
+} __packed;
+
+/**
+ * struct es58x_fd_tx_conf_msg - Channel configuration.
+ * @nominal_bittiming: Nominal bittiming.
+ * @samples_per_bit: type enum es58x_samples_per_bit.
+ * @sync_edge: type enum es58x_sync_edge.
+ * @physical_layer: type enum es58x_physical_layer.
+ * @echo_mode: type enum es58x_echo_mode.
+ * @ctrlmode: type enum es58x_fd_ctrlmode.
+ * @canfd_enabled: boolean (0: Classical CAN, 1: CAN and/or CANFD).
+ * @data_bittiming: Bittiming for flexible data-rate transmission.
+ * @tdc_enabled: Transmitter Delay Compensation switch (0: disabled,
+ *	1: enabled). On very high bitrates, the delay between when the
+ *	bit is sent and received on the CANTX and CANRX pins of the
+ *	transceiver start to be significant enough for errors to occur
+ *	and thus need to be compensated.
+ * @tdco: Transmitter Delay Compensation Offset. Offset value, in time
+ *	quanta, defining the delay between the start of the bit
+ *	reception on the CANRX pin of the transceiver and the SSP
+ *	(Secondary Sample Point). Valid values: 0 to 127.
+ * @tdcf: Transmitter Delay Compensation Filter window. Defines the
+ *	minimum value for the SSP position, in time quanta. The
+ *	feature is enabled when TDCF is configured to a value greater
+ *	than TDCO. Valid values: 0 to 127.
+ *
+ * Please refer to the microcontroller datasheet: "SAM
+ * E701/S70/V70/V71 Family" section 49 "Controller Area Network
+ * (MCAN)" for additional information.
+ */
+struct es58x_fd_tx_conf_msg {
+	struct es58x_fd_bittiming nominal_bittiming;
+	u8 samples_per_bit;
+	u8 sync_edge;
+	u8 physical_layer;
+	u8 echo_mode;
+	u8 ctrlmode;
+	u8 canfd_enabled;
+	struct es58x_fd_bittiming data_bittiming;
+	u8 tdc_enabled;
+	__le16 tdco;
+	__le16 tdcf;
+} __packed;
+
+#define ES58X_FD_CAN_CONF_LEN					\
+	(offsetof(struct es58x_fd_tx_conf_msg, canfd_enabled))
+#define ES58X_FD_CANFD_CONF_LEN (sizeof(struct es58x_fd_tx_conf_msg))
+
+struct es58x_fd_tx_can_msg {
+	u8 packet_idx;
+	__le32 can_id;
+	u8 flags;
+	union {
+		u8 dlc;		/* Only if cmd_id is ES58X_FD_CMD_TYPE_CAN */
+		u8 len;		/* Only if cmd_id is ES58X_FD_CMD_TYPE_CANFD */
+	} __packed;
+	u8 data[CANFD_MAX_DLEN];
+} __packed;
+
+#define ES58X_FD_CAN_TX_LEN						\
+	(offsetof(struct es58x_fd_tx_can_msg, data[CAN_MAX_DLEN]))
+#define ES58X_FD_CANFD_TX_LEN (sizeof(struct es58x_fd_tx_can_msg))
+
+struct es58x_fd_rx_can_msg {
+	__le64 timestamp;
+	__le32 can_id;
+	u8 flags;
+	union {
+		u8 dlc;		/* Only if cmd_id is ES58X_FD_CMD_TYPE_CAN */
+		u8 len;		/* Only if cmd_id is ES58X_FD_CMD_TYPE_CANFD */
+	} __packed;
+	u8 data[CANFD_MAX_DLEN];
+} __packed;
+
+#define ES58X_FD_CAN_RX_LEN						\
+	(offsetof(struct es58x_fd_rx_can_msg, data[CAN_MAX_DLEN]))
+#define ES58X_FD_CANFD_RX_LEN (sizeof(struct es58x_fd_rx_can_msg))
+
+struct es58x_fd_echo_msg {
+	__le64 timestamp;
+	u8 packet_idx;
+} __packed;
+
+struct es58x_fd_rx_event_msg {
+	__le64 timestamp;
+	__le32 can_id;
+	u8 flags;		/* type enum es58x_flag */
+	u8 error_type;		/* 0: event, 1: error */
+	u8 error_code;
+	u8 event_code;
+} __packed;
+
+struct es58x_fd_tx_ack_msg {
+	__le32 rx_cmd_ret_le32;	/* type enum es58x_cmd_ret_code_u32 */
+	__le16 tx_free_entries;	/* Number of remaining free entries in the device TX queue */
+} __packed;
+
+/**
+ * struct es58x_fd_urb_cmd - Commands received from or sent to the
+ *	ES58X FD device.
+ * @SOF: Start of Frame.
+ * @cmd_type: Command Type (type: enum es58x_fd_cmd_type). The CRC
+ *	calculation starts at this position.
+ * @cmd_id: Command ID (type: enum es58x_fd_cmd_id).
+ * @channel_idx: Channel index starting at 0.
+ * @msg_len: Length of the message, excluding CRC (i.e. length of the
+ *	union).
+ * @tx_conf_msg: Channel configuration.
+ * @tx_can_msg_buf: Concatenation of Tx messages. Type is "u8[]"
+ *	instead of "struct es58x_fd_tx_msg[]" because the structure
+ *	has a flexible size.
+ * @rx_can_msg_buf: Concatenation Rx messages. Type is "u8[]" instead
+ *	of "struct es58x_fd_rx_msg[]" because the structure has a
+ *	flexible size.
+ * @echo_msg: Array of echo messages (e.g. Tx messages being looped
+ *	back).
+ * @rx_event_msg: Error or event message.
+ * @tx_ack_msg: Tx acknowledgment message.
+ * @timestamp: Timestamp reply.
+ * @rx_cmd_ret_le32: Rx 32 bits return code (type: enum
+ *	es58x_cmd_ret_code_u32).
+ * @raw_msg: Message raw payload.
+ * @reserved_for_crc16_do_not_use: The structure ends with a
+ *	CRC16. Because the structures in above union are of variable
+ *	lengths, we can not predict the offset of the CRC in
+ *	advance. Use functions es58x_get_crc() and es58x_set_crc() to
+ *	manipulate it.
+ */
+struct es58x_fd_urb_cmd {
+	__le16 SOF;
+	u8 cmd_type;
+	u8 cmd_id;
+	u8 channel_idx;
+	__le16 msg_len;
+
+	union {
+		struct es58x_fd_tx_conf_msg tx_conf_msg;
+		u8 tx_can_msg_buf[ES58X_FD_TX_BULK_MAX * ES58X_FD_CANFD_TX_LEN];
+		u8 rx_can_msg_buf[ES58X_FD_RX_BULK_MAX * ES58X_FD_CANFD_RX_LEN];
+		struct es58x_fd_echo_msg echo_msg[ES58X_FD_ECHO_BULK_MAX];
+		struct es58x_fd_rx_event_msg rx_event_msg;
+		struct es58x_fd_tx_ack_msg tx_ack_msg;
+		__le64 timestamp;
+		__le32 rx_cmd_ret_le32;
+		u8 raw_msg[0];
+	} __packed;
+
+	__le16 reserved_for_crc16_do_not_use;
+} __packed;
+
+#define ES58X_FD_URB_CMD_HEADER_LEN (offsetof(struct es58x_fd_urb_cmd, raw_msg))
+#define ES58X_FD_TX_URB_CMD_MAX_LEN					\
+	ES58X_SIZEOF_URB_CMD(struct es58x_fd_urb_cmd, tx_can_msg_buf)
+#define ES58X_FD_RX_URB_CMD_MAX_LEN					\
+	ES58X_SIZEOF_URB_CMD(struct es58x_fd_urb_cmd, rx_can_msg_buf)
+
+#endif /* __ES58X_FD_H__ */

drivers/net/can/usb/peak_usb/pcan_usb.c

@@ -365,16 +365,11 @@ static int pcan_usb_get_serial(struct peak_usb_device *dev, u32 *serial_number)
 	int err;
 
 	err = pcan_usb_wait_rsp(dev, PCAN_USB_CMD_SN, PCAN_USB_GET, args);
-	if (err) {
-		netdev_err(dev->netdev, "getting serial failure: %d\n", err);
-	} else if (serial_number) {
-		__le32 tmp32;
-
-		memcpy(&tmp32, args, 4);
-		*serial_number = le32_to_cpu(tmp32);
-	}
-
+	if (err)
 		return err;
+	*serial_number = le32_to_cpup((__le32 *)args);
+
+	return 0;
 }
 
 /*
@@ -388,7 +383,7 @@ static int pcan_usb_get_device_id(struct peak_usb_device *dev, u32 *device_id)
 	err = pcan_usb_wait_rsp(dev, PCAN_USB_CMD_DEVID, PCAN_USB_GET, args);
 	if (err)
 		netdev_err(dev->netdev, "getting device id failure: %d\n", err);
-	else if (device_id)
+
 	*device_id = args[0];
 
 	return err;
@@ -399,14 +394,10 @@ static int pcan_usb_get_device_id(struct peak_usb_device *dev, u32 *device_id)
  */
 static int pcan_usb_update_ts(struct pcan_usb_msg_context *mc)
 {
-	__le16 tmp16;
-
-	if ((mc->ptr+2) > mc->end)
+	if ((mc->ptr + 2) > mc->end)
 		return -EINVAL;
 
-	memcpy(&tmp16, mc->ptr, 2);
-
-	mc->ts16 = le16_to_cpu(tmp16);
+	mc->ts16 = get_unaligned_le16(mc->ptr);
 
 	if (mc->rec_idx > 0)
 		peak_usb_update_ts_now(&mc->pdev->time_ref, mc->ts16);
@@ -423,16 +414,13 @@ static int pcan_usb_decode_ts(struct pcan_usb_msg_context *mc, u8 first_packet)
 {
 	/* only 1st packet supplies a word timestamp */
 	if (first_packet) {
-		__le16 tmp16;
-
 		if ((mc->ptr + 2) > mc->end)
 			return -EINVAL;
 
-		memcpy(&tmp16, mc->ptr, 2);
-		mc->ptr += 2;
-
-		mc->ts16 = le16_to_cpu(tmp16);
+		mc->ts16 = get_unaligned_le16(mc->ptr);
 		mc->prev_ts8 = mc->ts16 & 0x00ff;
+
+		mc->ptr += 2;
 	} else {
 		u8 ts8;
 
@@ -722,25 +710,17 @@ static int pcan_usb_decode_data(struct pcan_usb_msg_context *mc, u8 status_len)
 		return -ENOMEM;
 
 	if (status_len & PCAN_USB_STATUSLEN_EXT_ID) {
-		__le32 tmp32;
-
 		if ((mc->ptr + 4) > mc->end)
 			goto decode_failed;
 
-		memcpy(&tmp32, mc->ptr, 4);
+		cf->can_id = get_unaligned_le32(mc->ptr) >> 3 | CAN_EFF_FLAG;
 		mc->ptr += 4;
-
-		cf->can_id = (le32_to_cpu(tmp32) >> 3) | CAN_EFF_FLAG;
 	} else {
-		__le16 tmp16;
-
 		if ((mc->ptr + 2) > mc->end)
 			goto decode_failed;
 
-		memcpy(&tmp16, mc->ptr, 2);
+		cf->can_id = get_unaligned_le16(mc->ptr) >> 5;
 		mc->ptr += 2;
-
-		cf->can_id = le16_to_cpu(tmp16) >> 5;
 	}
 
 	can_frame_set_cc_len(cf, rec_len, mc->pdev->dev.can.ctrlmode);
@@ -854,15 +834,15 @@ static int pcan_usb_encode_msg(struct peak_usb_device *dev, struct sk_buff *skb,
 
 	/* can id */
 	if (cf->can_id & CAN_EFF_FLAG) {
-		__le32 tmp32 = cpu_to_le32((cf->can_id & CAN_ERR_MASK) << 3);
-
 		*pc |= PCAN_USB_STATUSLEN_EXT_ID;
-		memcpy(++pc, &tmp32, 4);
+		pc++;
+
+		put_unaligned_le32((cf->can_id & CAN_ERR_MASK) << 3, pc);
 		pc += 4;
 	} else {
-		__le16 tmp16 = cpu_to_le16((cf->can_id & CAN_ERR_MASK) << 5);
+		pc++;
 
-		memcpy(++pc, &tmp16, 2);
+		put_unaligned_le16((cf->can_id & CAN_ERR_MASK) << 5, pc);
 		pc += 2;
 	}
 
@@ -1039,7 +1019,7 @@ const struct peak_usb_adapter pcan_usb = {
 			      CAN_CTRLMODE_BERR_REPORTING |
 			      CAN_CTRLMODE_CC_LEN8_DLC,
 	.clock = {
-		.freq = PCAN_USB_CRYSTAL_HZ / 2 ,
+		.freq = PCAN_USB_CRYSTAL_HZ / 2,
 	},
 	.bittiming_const = &pcan_usb_const,
 
@@ -1050,7 +1030,6 @@ const struct peak_usb_adapter pcan_usb = {
 
 	/* timestamps usage */
 	.ts_used_bits = 16,
-	.ts_period = 24575, /* calibration period in ts. */
 	.us_per_ts_scale = PCAN_USB_TS_US_PER_TICK, /* us=(ts*scale) */
 	.us_per_ts_shift = PCAN_USB_TS_DIV_SHIFTER, /*  >> shift     */
 

drivers/net/can/usb/peak_usb/pcan_usb_core.c

@@ -27,28 +27,32 @@ MODULE_DESCRIPTION("CAN driver for PEAK-System USB adapters");
 MODULE_LICENSE("GPL v2");
 
 /* Table of devices that work with this driver */
-static struct usb_device_id peak_usb_table[] = {
-	{USB_DEVICE(PCAN_USB_VENDOR_ID, PCAN_USB_PRODUCT_ID)},
-	{USB_DEVICE(PCAN_USB_VENDOR_ID, PCAN_USBPRO_PRODUCT_ID)},
-	{USB_DEVICE(PCAN_USB_VENDOR_ID, PCAN_USBFD_PRODUCT_ID)},
-	{USB_DEVICE(PCAN_USB_VENDOR_ID, PCAN_USBPROFD_PRODUCT_ID)},
-	{USB_DEVICE(PCAN_USB_VENDOR_ID, PCAN_USBCHIP_PRODUCT_ID)},
-	{USB_DEVICE(PCAN_USB_VENDOR_ID, PCAN_USBX6_PRODUCT_ID)},
-	{} /* Terminating entry */
+static const struct usb_device_id peak_usb_table[] = {
+	{
+		USB_DEVICE(PCAN_USB_VENDOR_ID, PCAN_USB_PRODUCT_ID),
+		.driver_info = (kernel_ulong_t)&pcan_usb,
+	}, {
+		USB_DEVICE(PCAN_USB_VENDOR_ID, PCAN_USBPRO_PRODUCT_ID),
+		.driver_info = (kernel_ulong_t)&pcan_usb_pro,
+	}, {
+		USB_DEVICE(PCAN_USB_VENDOR_ID, PCAN_USBFD_PRODUCT_ID),
+		.driver_info = (kernel_ulong_t)&pcan_usb_fd,
+	}, {
+		USB_DEVICE(PCAN_USB_VENDOR_ID, PCAN_USBPROFD_PRODUCT_ID),
+		.driver_info = (kernel_ulong_t)&pcan_usb_pro_fd,
+	}, {
+		USB_DEVICE(PCAN_USB_VENDOR_ID, PCAN_USBCHIP_PRODUCT_ID),
+		.driver_info = (kernel_ulong_t)&pcan_usb_chip,
+	}, {
+		USB_DEVICE(PCAN_USB_VENDOR_ID, PCAN_USBX6_PRODUCT_ID),
+		.driver_info = (kernel_ulong_t)&pcan_usb_x6,
+	}, {
+		/* Terminating entry */
+	}
 };
 
 MODULE_DEVICE_TABLE(usb, peak_usb_table);
 
-/* List of supported PCAN-USB adapters (NULL terminated list) */
-static const struct peak_usb_adapter *const peak_usb_adapters_list[] = {
-	&pcan_usb,
-	&pcan_usb_pro,
-	&pcan_usb_fd,
-	&pcan_usb_pro_fd,
-	&pcan_usb_chip,
-	&pcan_usb_x6,
-};
-
 /*
  * dump memory
  */
@@ -624,6 +628,7 @@ static int peak_usb_ndo_stop(struct net_device *netdev)
 	/* can set bus off now */
 	if (dev->adapter->dev_set_bus) {
 		int err = dev->adapter->dev_set_bus(dev, 0);
+
 		if (err)
 			return err;
 	}
@@ -927,24 +932,11 @@ static void peak_usb_disconnect(struct usb_interface *intf)
 static int peak_usb_probe(struct usb_interface *intf,
 			  const struct usb_device_id *id)
 {
-	struct usb_device *usb_dev = interface_to_usbdev(intf);
-	const u16 usb_id_product = le16_to_cpu(usb_dev->descriptor.idProduct);
-	const struct peak_usb_adapter *peak_usb_adapter = NULL;
+	const struct peak_usb_adapter *peak_usb_adapter;
 	int i, err = -ENOMEM;
 
 	/* get corresponding PCAN-USB adapter */
-	for (i = 0; i < ARRAY_SIZE(peak_usb_adapters_list); i++)
-		if (peak_usb_adapters_list[i]->device_id == usb_id_product) {
-			peak_usb_adapter = peak_usb_adapters_list[i];
-			break;
-		}
-
-	if (!peak_usb_adapter) {
-		/* should never come except device_id bad usage in this file */
-		pr_err("%s: didn't find device id. 0x%x in devices list\n",
-			PCAN_USB_DRIVER_NAME, usb_id_product);
-		return -ENODEV;
-	}
+	peak_usb_adapter = (const struct peak_usb_adapter *)id->driver_info;
 
 	/* got corresponding adapter: check if it handles current interface */
 	if (peak_usb_adapter->intf_probe) {

drivers/net/can/usb/peak_usb/pcan_usb_core.h

@@ -73,7 +73,6 @@ struct peak_usb_adapter {
 	u8 ep_msg_in;
 	u8 ep_msg_out[PCAN_USB_MAX_CHANNEL];
 	u8 ts_used_bits;
-	u32 ts_period;
 	u8 us_per_ts_shift;
 	u32 us_per_ts_scale;
 
@@ -114,8 +113,6 @@ struct peak_usb_device {
 	unsigned int ctrl_idx;
 	u32 state;
 
-	struct sk_buff *echo_skb[PCAN_USB_MAX_TX_URBS];
-
 	struct usb_device *udev;
 	struct net_device *netdev;
 
@@ -132,8 +129,6 @@ struct peak_usb_device {
 	u8 ep_msg_in;
 	u8 ep_msg_out;
 
-	u16 bus_load;
-
 	struct peak_usb_device *prev_siblings;
 	struct peak_usb_device *next_siblings;
 };

drivers/net/can/usb/peak_usb/pcan_usb_fd.c

@@ -1081,7 +1081,6 @@ const struct peak_usb_adapter pcan_usb_fd = {
 
 	/* timestamps usage */
 	.ts_used_bits = 32,
-	.ts_period = 1000000, /* calibration period in ts. */
 	.us_per_ts_scale = 1, /* us = (ts * scale) >> shift */
 	.us_per_ts_shift = 0,
 
@@ -1156,7 +1155,6 @@ const struct peak_usb_adapter pcan_usb_chip = {
 
 	/* timestamps usage */
 	.ts_used_bits = 32,
-	.ts_period = 1000000, /* calibration period in ts. */
 	.us_per_ts_scale = 1, /* us = (ts * scale) >> shift */
 	.us_per_ts_shift = 0,
 
@@ -1231,7 +1229,6 @@ const struct peak_usb_adapter pcan_usb_pro_fd = {
 
 	/* timestamps usage */
 	.ts_used_bits = 32,
-	.ts_period = 1000000, /* calibration period in ts. */
 	.us_per_ts_scale = 1, /* us = (ts * scale) >> shift */
 	.us_per_ts_shift = 0,
 
@@ -1306,7 +1303,6 @@ const struct peak_usb_adapter pcan_usb_x6 = {
 
 	/* timestamps usage */
 	.ts_used_bits = 32,
-	.ts_period = 1000000, /* calibration period in ts. */
 	.us_per_ts_scale = 1, /* us = (ts * scale) >> shift */
 	.us_per_ts_shift = 0,
 

drivers/net/can/usb/peak_usb/pcan_usb_pro.c

@@ -290,7 +290,7 @@ static int pcan_usb_pro_wait_rsp(struct peak_usb_device *dev,
 					   pr->data_type);
 
 			/* check if channel in response corresponds too */
-			else if ((req_channel != 0xff) && \
+			else if ((req_channel != 0xff) &&
 				(pr->bus_act.channel != req_channel))
 				netdev_err(dev->netdev,
 					"got rsp %xh but on chan%u: ignored\n",
@@ -439,7 +439,6 @@ static int pcan_usb_pro_get_device_id(struct peak_usb_device *dev,
 		return err;
 
 	pdn = (struct pcan_usb_pro_devid *)pc;
-	if (device_id)
 	*device_id = le32_to_cpu(pdn->serial_num);
 
 	return err;
@@ -1058,7 +1057,6 @@ const struct peak_usb_adapter pcan_usb_pro = {
 
 	/* timestamps usage */
 	.ts_used_bits = 32,
-	.ts_period = 1000000, /* calibration period in ts. */
 	.us_per_ts_scale = 1, /* us = (ts * scale) >> shift */
 	.us_per_ts_shift = 0,