can: CAN Network device driver and Netlink interface

The CAN network device driver interface provides a generic interface to
setup, configure and monitor CAN network devices. It exports a set of
common data structures and functions, which all real CAN network device
drivers should use. Please have a look to the SJA1000 or MSCAN driver
to understand how to use them. The name of the module is can-dev.ko.

Furthermore, it adds a Netlink interface allowing to configure the CAN
device using the program "ip" from the iproute2 utility suite.

For further information please check "Documentation/networking/can.txt"
Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/can/Kconfig

@@ -12,6 +12,29 @@ config CAN_VCAN
 	  This driver can also be built as a module.  If so, the module
 	  will be called vcan.
 
+config CAN_DEV
+	tristate "Platform CAN drivers with Netlink support"
+	depends on CAN
+	default Y
+	---help---
+	  Enables the common framework for platform CAN drivers with Netlink
+	  support. This is the standard library for CAN drivers.
+	  If unsure, say Y.
+
+config CAN_CALC_BITTIMING
+	bool "CAN bit-timing calculation"
+	depends on CAN_DEV
+	default Y
+	---help---
+	  If enabled, CAN bit-timing parameters will be calculated for the
+	  bit-rate specified via Netlink argument "bitrate" when the device
+	  get started. This works fine for the most common CAN controllers
+	  with standard bit-rates but may fail for exotic bit-rates or CAN
+	  source clock frequencies. Disabling saves some space, but then the
+	  bit-timing parameters must be specified directly using the Netlink
+	  arguments "tq", "prop_seg", "phase_seg1", "phase_seg2" and "sjw".
+	  If unsure, say Y.
+
 config CAN_DEBUG_DEVICES
 	bool "CAN devices debugging messages"
 	depends on CAN

drivers/net/can/Makefile

@@ -3,3 +3,8 @@
 #
 
 obj-$(CONFIG_CAN_VCAN)		+= vcan.o
+
+obj-$(CONFIG_CAN_DEV)		+= can-dev.o
+can-dev-y			:= dev.o
+
+ccflags-$(CONFIG_CAN_DEBUG_DEVICES) := -DDEBUG

include/linux/can/Kbuild

 header-y += raw.h
 header-y += bcm.h
 header-y += error.h
+header-y += netlink.h

include/linux/can/dev.h

+/*
+ * linux/can/dev.h
+ *
+ * Definitions for the CAN network device driver interface
+ *
+ * Copyright (C) 2006 Andrey Volkov <avolkov@varma-el.com>
+ *               Varma Electronics Oy
+ *
+ * Copyright (C) 2008 Wolfgang Grandegger <wg@grandegger.com>
+ *
+ * Send feedback to <socketcan-users@lists.berlios.de>
+ */
+
+#ifndef CAN_DEV_H
+#define CAN_DEV_H
+
+#include <linux/can/netlink.h>
+#include <linux/can/error.h>
+
+/*
+ * CAN mode
+ */
+enum can_mode {
+	CAN_MODE_STOP = 0,
+	CAN_MODE_START,
+	CAN_MODE_SLEEP
+};
+
+/*
+ * CAN common private data
+ */
+#define CAN_ECHO_SKB_MAX  4
+
+struct can_priv {
+	struct can_device_stats can_stats;
+
+	struct can_bittiming bittiming;
+	struct can_bittiming_const *bittiming_const;
+	struct can_clock clock;
+
+	enum can_state state;
+	u32 ctrlmode;
+
+	int restart_ms;
+	struct timer_list restart_timer;
+
+	struct sk_buff *echo_skb[CAN_ECHO_SKB_MAX];
+
+	int (*do_set_bittiming)(struct net_device *dev);
+	int (*do_set_mode)(struct net_device *dev, enum can_mode mode);
+	int (*do_get_state)(const struct net_device *dev,
+			    enum can_state *state);
+};
+
+struct net_device *alloc_candev(int sizeof_priv);
+void free_candev(struct net_device *dev);
+
+int open_candev(struct net_device *dev);
+void close_candev(struct net_device *dev);
+
+int register_candev(struct net_device *dev);
+void unregister_candev(struct net_device *dev);
+
+int can_restart_now(struct net_device *dev);
+void can_bus_off(struct net_device *dev);
+
+void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev, int idx);
+void can_get_echo_skb(struct net_device *dev, int idx);
+
+#endif /* CAN_DEV_H */

include/linux/can/netlink.h

+/*
+ * linux/can/netlink.h
+ *
+ * Definitions for the CAN netlink interface
+ *
+ * Copyright (c) 2009 Wolfgang Grandegger <wg@grandegger.com>
+ *
+ * Send feedback to <socketcan-users@lists.berlios.de>
+ *
+ */
+
+#ifndef CAN_NETLINK_H
+#define CAN_NETLINK_H
+
+#include <linux/types.h>
+
+/*
+ * CAN bit-timing parameters
+ *
+ * For futher information, please read chapter "8 BIT TIMING
+ * REQUIREMENTS" of the "Bosch CAN Specification version 2.0"
+ * at http://www.semiconductors.bosch.de/pdf/can2spec.pdf.
+ */
+struct can_bittiming {
+	__u32 bitrate;		/* Bit-rate in bits/second */
+	__u32 sample_point;	/* Sample point in one-tenth of a percent */
+	__u32 tq;		/* Time quanta (TQ) in nanoseconds */
+	__u32 prop_seg;		/* Propagation segment in TQs */
+	__u32 phase_seg1;	/* Phase buffer segment 1 in TQs */
+	__u32 phase_seg2;	/* Phase buffer segment 2 in TQs */
+	__u32 sjw;		/* Synchronisation jump width in TQs */
+	__u32 brp;		/* Bit-rate prescaler */
+};
+
+/*
+ * CAN harware-dependent bit-timing constant
+ *
+ * Used for calculating and checking bit-timing parameters
+ */
+struct can_bittiming_const {
+	char name[16];		/* Name of the CAN controller hardware */
+	__u32 tseg1_min;	/* Time segement 1 = prop_seg + phase_seg1 */
+	__u32 tseg1_max;
+	__u32 tseg2_min;	/* Time segement 2 = phase_seg2 */
+	__u32 tseg2_max;
+	__u32 sjw_max;		/* Synchronisation jump width */
+	__u32 brp_min;		/* Bit-rate prescaler */
+	__u32 brp_max;
+	__u32 brp_inc;
+};
+
+/*
+ * CAN clock parameters
+ */
+struct can_clock {
+	__u32 freq;		/* CAN system clock frequency in Hz */
+};
+
+/*
+ * CAN operational and error states
+ */
+enum can_state {
+	CAN_STATE_ERROR_ACTIVE = 0,	/* RX/TX error count < 96 */
+	CAN_STATE_ERROR_WARNING,	/* RX/TX error count < 128 */
+	CAN_STATE_ERROR_PASSIVE,	/* RX/TX error count < 256 */
+	CAN_STATE_BUS_OFF,		/* RX/TX error count >= 256 */
+	CAN_STATE_STOPPED,		/* Device is stopped */
+	CAN_STATE_SLEEPING,		/* Device is sleeping */
+	CAN_STATE_MAX
+};
+
+/*
+ * CAN controller mode
+ */
+struct can_ctrlmode {
+	__u32 mask;
+	__u32 flags;
+};
+
+#define CAN_CTRLMODE_LOOPBACK	0x1	/* Loopback mode */
+#define CAN_CTRLMODE_LISTENONLY	0x2 	/* Listen-only mode */
+#define CAN_CTRLMODE_3_SAMPLES	0x4	/* Triple sampling mode */
+
+/*
+ * CAN device statistics
+ */
+struct can_device_stats {
+	__u32 bus_error;	/* Bus errors */
+	__u32 error_warning;	/* Changes to error warning state */
+	__u32 error_passive;	/* Changes to error passive state */
+	__u32 bus_off;		/* Changes to bus off state */
+	__u32 arbitration_lost; /* Arbitration lost errors */
+	__u32 restarts;		/* CAN controller re-starts */
+};
+
+/*
+ * CAN netlink interface
+ */
+enum {
+	IFLA_CAN_UNSPEC,
+	IFLA_CAN_BITTIMING,
+	IFLA_CAN_BITTIMING_CONST,
+	IFLA_CAN_CLOCK,
+	IFLA_CAN_STATE,
+	IFLA_CAN_CTRLMODE,
+	IFLA_CAN_RESTART_MS,
+	IFLA_CAN_RESTART,
+	__IFLA_CAN_MAX
+};
+
+#define IFLA_CAN_MAX	(__IFLA_CAN_MAX - 1)
+
+#endif /* CAN_NETLINK_H */