can: flexcan: Add provision for variable payload size

Till now the flexcan module supported 8 byte payload size as per CAN 2.0
specifications. But now upcoming flexcan module in NXP LX2160A SOC
supports CAN FD protocol too. The Message buffers need to be configured
to have payload size 64 bytes.

Therefore, added provision in the driver for payload size to be 64 bytes.
Signed-off-by: Pankaj Bansal <pankaj.bansal@nxp.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/flexcan.c

@@ -140,9 +140,7 @@
 /* Errata ERR005829 step7: Reserve first valid MB */
 #define FLEXCAN_TX_MB_RESERVED_OFF_FIFO		8
 #define FLEXCAN_TX_MB_RESERVED_OFF_TIMESTAMP	0
-#define FLEXCAN_TX_MB				63
 #define FLEXCAN_RX_MB_OFF_TIMESTAMP_FIRST	(FLEXCAN_TX_MB_RESERVED_OFF_TIMESTAMP + 1)
-#define FLEXCAN_RX_MB_OFF_TIMESTAMP_LAST	(FLEXCAN_TX_MB - 1)
 #define FLEXCAN_IFLAG_MB(x)		BIT((x) & 0x1f)
 #define FLEXCAN_IFLAG_RX_FIFO_OVERFLOW	BIT(7)
 #define FLEXCAN_IFLAG_RX_FIFO_WARN	BIT(6)
@@ -198,7 +196,7 @@
 struct flexcan_mb {
 	u32 can_ctrl;
 	u32 can_id;
-	u32 data[2];
+	u32 data[];
 };
 
 /* Structure of the hardware registers */
@@ -227,7 +225,7 @@ struct flexcan_regs {
 	u32 rxfgmask;		/* 0x48 */
 	u32 rxfir;		/* 0x4c */
 	u32 _reserved3[12];	/* 0x50 */
-	struct flexcan_mb mb[64];	/* 0x80 */
+	u8 mb[1024];		/* 0x80 */
 	/* FIFO-mode:
 	 *			MB
 	 * 0x080...0x08f	0	RX message buffer
@@ -270,7 +268,11 @@ struct flexcan_priv {
 	struct can_rx_offload offload;
 
 	struct flexcan_regs __iomem *regs;
+	struct flexcan_mb __iomem *tx_mb;
 	struct flexcan_mb __iomem *tx_mb_reserved;
+	u8 tx_mb_idx;
+	u8 mb_count;
+	u8 mb_size;
 	u32 reg_ctrl_default;
 	u32 reg_imask1_default;
 	u32 reg_imask2_default;
@@ -364,6 +366,16 @@ static inline void flexcan_write_le(u32 val, void __iomem *addr)
 	iowrite32(val, addr);
 }
 
+static struct flexcan_mb __iomem *flexcan_get_mb(const struct flexcan_priv *priv,
+						 u8 mb_index)
+{
+	if (WARN_ON(mb_index >= priv->mb_count))
+		return NULL;
+
+	return (struct flexcan_mb __iomem *)
+		(&priv->regs->mb[priv->mb_size * mb_index]);
+}
+
 static void flexcan_enable_wakeup_irq(struct flexcan_priv *priv, bool enable)
 {
 	struct flexcan_regs __iomem *regs = priv->regs;
@@ -569,11 +581,11 @@ static int flexcan_get_berr_counter(const struct net_device *dev,
 static netdev_tx_t flexcan_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	const struct flexcan_priv *priv = netdev_priv(dev);
-	struct flexcan_regs __iomem *regs = priv->regs;
 	struct can_frame *cf = (struct can_frame *)skb->data;
 	u32 can_id;
 	u32 data;
 	u32 ctrl = FLEXCAN_MB_CODE_TX_DATA | (cf->can_dlc << 16);
+	int i;
 
 	if (can_dropped_invalid_skb(dev, skb))
 		return NETDEV_TX_OK;
@@ -590,19 +602,15 @@ static netdev_tx_t flexcan_start_xmit(struct sk_buff *skb, struct net_device *de
 	if (cf->can_id & CAN_RTR_FLAG)
 		ctrl |= FLEXCAN_MB_CNT_RTR;
 
-	if (cf->can_dlc > 0) {
-		data = be32_to_cpup((__be32 *)&cf->data[0]);
-		priv->write(data, &regs->mb[FLEXCAN_TX_MB].data[0]);
-	}
-	if (cf->can_dlc > 4) {
-		data = be32_to_cpup((__be32 *)&cf->data[4]);
-		priv->write(data, &regs->mb[FLEXCAN_TX_MB].data[1]);
+	for (i = 0; i < cf->can_dlc; i += sizeof(u32)) {
+		data = be32_to_cpup((__be32 *)&cf->data[i]);
+		priv->write(data, &priv->tx_mb->data[i / sizeof(u32)]);
 	}
 
 	can_put_echo_skb(skb, dev, 0);
 
-	priv->write(can_id, &regs->mb[FLEXCAN_TX_MB].can_id);
-	priv->write(ctrl, &regs->mb[FLEXCAN_TX_MB].can_ctrl);
+	priv->write(can_id, &priv->tx_mb->can_id);
+	priv->write(ctrl, &priv->tx_mb->can_ctrl);
 
 	/* Errata ERR005829 step8:
 	 * Write twice INACTIVE(0x8) code to first MB.
@@ -729,8 +737,11 @@ static unsigned int flexcan_mailbox_read(struct can_rx_offload *offload,
 {
 	struct flexcan_priv *priv = rx_offload_to_priv(offload);
 	struct flexcan_regs __iomem *regs = priv->regs;
-	struct flexcan_mb __iomem *mb = &regs->mb[n];
+	struct flexcan_mb __iomem *mb;
 	u32 reg_ctrl, reg_id, reg_iflag1;
+	int i;
+
+	mb = flexcan_get_mb(priv, n);
 
 	if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP) {
 		u32 code;
@@ -771,8 +782,10 @@ static unsigned int flexcan_mailbox_read(struct can_rx_offload *offload,
 		cf->can_id |= CAN_RTR_FLAG;
 	cf->can_dlc = get_can_dlc((reg_ctrl >> 16) & 0xf);
 
-	*(__be32 *)(cf->data + 0) = cpu_to_be32(priv->read(&mb->data[0]));
-	*(__be32 *)(cf->data + 4) = cpu_to_be32(priv->read(&mb->data[1]));
+	for (i = 0; i < cf->can_dlc; i += sizeof(u32)) {
+		__be32 data = cpu_to_be32(priv->read(&mb->data[i / sizeof(u32)]));
+		*(__be32 *)(cf->data + i) = data;
+	}
 
 	/* mark as read */
 	if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP) {
@@ -801,7 +814,7 @@ static inline u64 flexcan_read_reg_iflag_rx(struct flexcan_priv *priv)
 	u32 iflag1, iflag2;
 
 	iflag2 = priv->read(&regs->iflag2) & priv->reg_imask2_default &
-		~FLEXCAN_IFLAG_MB(FLEXCAN_TX_MB);
+		~FLEXCAN_IFLAG_MB(priv->tx_mb_idx);
 	iflag1 = priv->read(&regs->iflag1) & priv->reg_imask1_default;
 
 	return (u64)iflag2 << 32 | iflag1;
@@ -851,8 +864,8 @@ static irqreturn_t flexcan_irq(int irq, void *dev_id)
 	reg_iflag2 = priv->read(&regs->iflag2);
 
 	/* transmission complete interrupt */
-	if (reg_iflag2 & FLEXCAN_IFLAG_MB(FLEXCAN_TX_MB)) {
-		u32 reg_ctrl = priv->read(&regs->mb[FLEXCAN_TX_MB].can_ctrl);
+	if (reg_iflag2 & FLEXCAN_IFLAG_MB(priv->tx_mb_idx)) {
+		u32 reg_ctrl = priv->read(&priv->tx_mb->can_ctrl);
 
 		handled = IRQ_HANDLED;
 		stats->tx_bytes += can_rx_offload_get_echo_skb(&priv->offload,
@@ -862,8 +875,8 @@ static irqreturn_t flexcan_irq(int irq, void *dev_id)
 
 		/* after sending a RTR frame MB is in RX mode */
 		priv->write(FLEXCAN_MB_CODE_TX_INACTIVE,
-			    &regs->mb[FLEXCAN_TX_MB].can_ctrl);
-		priv->write(FLEXCAN_IFLAG_MB(FLEXCAN_TX_MB), &regs->iflag2);
+			    &priv->tx_mb->can_ctrl);
+		priv->write(FLEXCAN_IFLAG_MB(priv->tx_mb_idx), &regs->iflag2);
 		netif_wake_queue(dev);
 	}
 
@@ -976,6 +989,7 @@ static int flexcan_chip_start(struct net_device *dev)
 	struct flexcan_regs __iomem *regs = priv->regs;
 	u32 reg_mcr, reg_ctrl, reg_ctrl2, reg_mecr;
 	int err, i;
+	struct flexcan_mb __iomem *mb;
 
 	/* enable module */
 	err = flexcan_chip_enable(priv);
@@ -1003,7 +1017,7 @@ static int flexcan_chip_start(struct net_device *dev)
 	reg_mcr &= ~FLEXCAN_MCR_MAXMB(0xff);
 	reg_mcr |= FLEXCAN_MCR_FRZ | FLEXCAN_MCR_HALT | FLEXCAN_MCR_SUPV |
 		FLEXCAN_MCR_WRN_EN | FLEXCAN_MCR_IRMQ | FLEXCAN_MCR_IDAM_C |
-		FLEXCAN_MCR_MAXMB(FLEXCAN_TX_MB);
+		FLEXCAN_MCR_MAXMB(priv->tx_mb_idx);
 
 	/* MCR
 	 *
@@ -1077,14 +1091,16 @@ static int flexcan_chip_start(struct net_device *dev)
 
 	if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP) {
 		for (i = priv->offload.mb_first; i <= priv->offload.mb_last; i++) {
+			mb = flexcan_get_mb(priv, i);
 			priv->write(FLEXCAN_MB_CODE_RX_EMPTY,
-				    &regs->mb[i].can_ctrl);
+				    &mb->can_ctrl);
 		}
 	} else {
 		/* clear and invalidate unused mailboxes first */
-		for (i = FLEXCAN_TX_MB_RESERVED_OFF_FIFO; i <= ARRAY_SIZE(regs->mb); i++) {
+		for (i = FLEXCAN_TX_MB_RESERVED_OFF_FIFO; i <= priv->mb_count; i++) {
+			mb = flexcan_get_mb(priv, i);
 			priv->write(FLEXCAN_MB_CODE_RX_INACTIVE,
-				    &regs->mb[i].can_ctrl);
+				    &mb->can_ctrl);
 		}
 	}
 
@@ -1094,7 +1110,7 @@ static int flexcan_chip_start(struct net_device *dev)
 
 	/* mark TX mailbox as INACTIVE */
 	priv->write(FLEXCAN_MB_CODE_TX_INACTIVE,
-		    &regs->mb[FLEXCAN_TX_MB].can_ctrl);
+		    &priv->tx_mb->can_ctrl);
 
 	/* acceptance mask/acceptance code (accept everything) */
 	priv->write(0x0, &regs->rxgmask);
@@ -1105,7 +1121,7 @@ static int flexcan_chip_start(struct net_device *dev)
 		priv->write(0x0, &regs->rxfgmask);
 
 	/* clear acceptance filters */
-	for (i = 0; i < ARRAY_SIZE(regs->mb); i++)
+	for (i = 0; i < priv->mb_count; i++)
 		priv->write(0, &regs->rximr[i]);
 
 	/* On Vybrid, disable memory error detection interrupts
@@ -1188,7 +1204,6 @@ static void flexcan_chip_stop(struct net_device *dev)
 static int flexcan_open(struct net_device *dev)
 {
 	struct flexcan_priv *priv = netdev_priv(dev);
-	struct flexcan_regs __iomem *regs = priv->regs;
 	int err;
 
 	err = clk_prepare_enable(priv->clk_ipg);
@@ -1207,13 +1222,20 @@ static int flexcan_open(struct net_device *dev)
 	if (err)
 		goto out_close;
 
+	priv->mb_size = sizeof(struct flexcan_mb) + CAN_MAX_DLEN;
+	priv->mb_count = sizeof(priv->regs->mb) / priv->mb_size;
+
 	if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP)
-		priv->tx_mb_reserved = &regs->mb[FLEXCAN_TX_MB_RESERVED_OFF_TIMESTAMP];
+		priv->tx_mb_reserved =
+			flexcan_get_mb(priv, FLEXCAN_TX_MB_RESERVED_OFF_TIMESTAMP);
 	else
-		priv->tx_mb_reserved = &regs->mb[FLEXCAN_TX_MB_RESERVED_OFF_FIFO];
+		priv->tx_mb_reserved =
+			flexcan_get_mb(priv, FLEXCAN_TX_MB_RESERVED_OFF_FIFO);
+	priv->tx_mb_idx = priv->mb_count - 1;
+	priv->tx_mb = flexcan_get_mb(priv, priv->tx_mb_idx);
 
 	priv->reg_imask1_default = 0;
-	priv->reg_imask2_default = FLEXCAN_IFLAG_MB(FLEXCAN_TX_MB);
+	priv->reg_imask2_default = FLEXCAN_IFLAG_MB(priv->tx_mb_idx);
 
 	priv->offload.mailbox_read = flexcan_mailbox_read;
 
@@ -1221,7 +1243,7 @@ static int flexcan_open(struct net_device *dev)
 		u64 imask;
 
 		priv->offload.mb_first = FLEXCAN_RX_MB_OFF_TIMESTAMP_FIRST;
-		priv->offload.mb_last = FLEXCAN_RX_MB_OFF_TIMESTAMP_LAST;
+		priv->offload.mb_last = priv->mb_count - 2;
 
 		imask = GENMASK_ULL(priv->offload.mb_last,
 				    priv->offload.mb_first);