[PATCH v3 7/7] net: can: flexcan: use CAN FD frames for Tx/Rx

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Use can FD frames for Tx/Rx operations. This would be needed in upcoming
SOC LX2160A, which supports CAN FD protocol

Signed-off-by: Pankaj Bansal <pankaj.bansal@xxxxxxx>
---

Notes:
    V3:
     - introduced fd_enable in rx_offload structure. This boolean indicates if
       the FD mode is enabled or not.
     - Based on fd_enable, send the CAN FD or CAN 2.0 frame to mailbox_read.
     - in mailbox_read, detect the type of frame from fd_enable and fill the
       values accordingly.
     - in xmit function, detect the type of SKB received. if CAN FD SKB is
       detected, tread its data as canfd_frame otherwise can_frame. Then fill
       the values accordingly.
    V2:
     - No change

 drivers/net/can/flexcan.c      | 80 +++++++++++++++++++++++---------
 drivers/net/can/rx-offload.c   | 35 +++++++++++---
 include/linux/can/rx-offload.h |  4 +-
 3 files changed, 89 insertions(+), 30 deletions(-)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index c9edfc808f8f..52b0d19c80f0 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -540,30 +540,48 @@ 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 can_frame *cf = (struct can_frame *)skb->data;
+	struct can_frame *cf;
+	struct canfd_frame *cf_fd;
 	u32 can_id;
 	u32 data;
-	u32 ctrl = FLEXCAN_MB_CODE_TX_DATA | (cf->can_dlc << 16);
-	u8 can_dlc_dword, i;
+	u32 ctrl = FLEXCAN_MB_CODE_TX_DATA;
+	u8 can_dlc_dword, i, *pframe_data;
 
 	if (can_dropped_invalid_skb(dev, skb))
 		return NETDEV_TX_OK;
 
 	netif_stop_queue(dev);
 
-	if (cf->can_id & CAN_EFF_FLAG) {
-		can_id = cf->can_id & CAN_EFF_MASK;
-		ctrl |= FLEXCAN_MB_CNT_IDE | FLEXCAN_MB_CNT_SRR;
+	if (can_is_canfd_skb(skb)) {
+		cf_fd = (struct canfd_frame *)skb->data;
+		if (cf_fd->can_id & CAN_EFF_FLAG) {
+			can_id = cf_fd->can_id & CAN_EFF_MASK;
+			ctrl |= FLEXCAN_MB_CNT_IDE | FLEXCAN_MB_CNT_SRR;
+		} else {
+			can_id = (cf_fd->can_id & CAN_SFF_MASK) << 18;
+		}
+
+		ctrl |= (can_len2dlc(cf_fd->len) << 16);
+		can_dlc_dword = (cf_fd->len + sizeof(u32) - 1) / sizeof(u32);
+		pframe_data = cf_fd->data;
 	} else {
-		can_id = (cf->can_id & CAN_SFF_MASK) << 18;
-	}
+		cf = (struct can_frame *)skb->data;
+		if (cf->can_id & CAN_EFF_FLAG) {
+			can_id = cf->can_id & CAN_EFF_MASK;
+			ctrl |= FLEXCAN_MB_CNT_IDE | FLEXCAN_MB_CNT_SRR;
+		} else {
+			can_id = (cf->can_id & CAN_SFF_MASK) << 18;
+		}
+		if (cf->can_id & CAN_RTR_FLAG)
+			ctrl |= FLEXCAN_MB_CNT_RTR;
 
-	if (cf->can_id & CAN_RTR_FLAG)
-		ctrl |= FLEXCAN_MB_CNT_RTR;
+		ctrl |= (cf->can_dlc << 16);
+		can_dlc_dword = (cf->can_dlc + sizeof(u32) - 1) / sizeof(u32);
+		pframe_data = cf->data;
+	}
 
-	can_dlc_dword = (cf->can_dlc + sizeof(u32) - 1) / sizeof(u32);
 	for (i = 0; i < can_dlc_dword; i++) {
-		data = be32_to_cpup((__be32 *)&cf->data[(i * sizeof(u32))]);
+		data = be32_to_cpup((__be32 *)&pframe_data[(i * sizeof(u32))]);
 		priv->write(data, &priv->tx_mb->data[i]);
 	}
 
@@ -684,15 +702,18 @@ static inline struct flexcan_priv *rx_offload_to_priv(struct can_rx_offload *off
 }
 
 static unsigned int flexcan_mailbox_read(struct can_rx_offload *offload,
-					 struct can_frame *cf,
+					 void *frame,
 					 u32 *timestamp, unsigned int n)
 {
 	struct flexcan_priv *priv = rx_offload_to_priv(offload);
 	struct flexcan_regs __iomem *regs = priv->regs;
 	struct flexcan_mb __iomem *mb;
+	struct can_frame *cf;
+	struct canfd_frame *cf_fd;
 	u32 reg_ctrl, reg_id, reg_iflag1;
 	__be32 data;
-	u8 can_dlc_dword, i;
+	u8 can_dlc_dword, i, *pframe_data;
+	canid_t can_id;
 
 	mb = flexcan_get_mb(priv, n);
 
@@ -727,18 +748,30 @@ static unsigned int flexcan_mailbox_read(struct can_rx_offload *offload,
 
 	reg_id = priv->read(&mb->can_id);
 	if (reg_ctrl & FLEXCAN_MB_CNT_IDE)
-		cf->can_id = ((reg_id >> 0) & CAN_EFF_MASK) | CAN_EFF_FLAG;
+		can_id = ((reg_id >> 0) & CAN_EFF_MASK) | CAN_EFF_FLAG;
 	else
-		cf->can_id = (reg_id >> 18) & CAN_SFF_MASK;
+		can_id = (reg_id >> 18) & CAN_SFF_MASK;
 
 	if (reg_ctrl & FLEXCAN_MB_CNT_RTR)
-		cf->can_id |= CAN_RTR_FLAG;
-	cf->can_dlc = get_can_dlc((reg_ctrl >> 16) & 0xf);
+		can_id |= CAN_RTR_FLAG;
+
+	if (offload->fd_enable) {
+		cf_fd = (struct canfd_frame *)frame;
+		cf_fd->can_id = can_id;
+		cf_fd->len = can_dlc2len((reg_ctrl >> 16) & 0xf);
+		can_dlc_dword = (cf_fd->len + sizeof(u32) - 1) / sizeof(u32);
+		pframe_data = cf_fd->data;
+	} else {
+		cf = (struct can_frame *)frame;
+		cf->can_id = can_id;
+		cf->can_dlc = get_can_dlc((reg_ctrl >> 16) & 0xf);
+		can_dlc_dword = (cf->can_dlc + sizeof(u32) - 1) / sizeof(u32);
+		pframe_data = cf->data;
+	}
 
-	can_dlc_dword = (cf->can_dlc + sizeof(u32) - 1) / sizeof(u32);
 	for (i = 0; i < can_dlc_dword; i++) {
 		data = cpu_to_be32(priv->read(&mb->data[i]));
-		*(__be32 *)(cf->data + (i * sizeof(u32))) = data;
+		*(__be32 *)(pframe_data + (i * sizeof(u32))) = data;
 	}
 
 	/* mark as read */
@@ -1152,10 +1185,13 @@ static int flexcan_open(struct net_device *dev)
 	if (err)
 		goto out_close;
 
-	if (priv->can.ctrlmode & CAN_CTRLMODE_FD)
+	if (priv->can.ctrlmode & CAN_CTRLMODE_FD) {
+		priv->offload.fd_enable = true;
 		mb_size = sizeof(struct flexcan_mb) + CANFD_MAX_DLEN;
-	else
+	} else {
+		priv->offload.fd_enable = false;
 		mb_size = sizeof(struct flexcan_mb) + CAN_MAX_DLEN;
+	}
 
 	if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP) {
 		priv->tx_mb_idx = FLEXCAN_TX_MB_OFF_TIMESTAMP;
diff --git a/drivers/net/can/rx-offload.c b/drivers/net/can/rx-offload.c
index d94dae216820..18a23f919771 100644
--- a/drivers/net/can/rx-offload.c
+++ b/drivers/net/can/rx-offload.c
@@ -55,11 +55,19 @@ static int can_rx_offload_napi_poll(struct napi_struct *napi, int quota)
 
 	while ((work_done < quota) &&
 	       (skb = skb_dequeue(&offload->skb_queue))) {
-		struct can_frame *cf = (struct can_frame *)skb->data;
+		struct can_frame *cf;
+		struct canfd_frame *cf_fd;
+
+		if (can_is_canfd_skb(skb)) {
+			cf_fd = (struct canfd_frame *)skb->data;
+			stats->rx_bytes += cf_fd->len;
+		} else {
+			cf = (struct can_frame *)skb->data;
+			stats->rx_bytes += cf->can_dlc;
+		}
 
 		work_done++;
 		stats->rx_packets++;
-		stats->rx_bytes += cf->can_dlc;
 		netif_receive_skb(skb);
 	}
 
@@ -121,19 +129,29 @@ static struct sk_buff *can_rx_offload_offload_one(struct can_rx_offload *offload
 	struct sk_buff *skb = NULL;
 	struct can_rx_offload_cb *cb;
 	struct can_frame *cf;
+	struct canfd_frame *cf_fd;
 	int ret;
 
 	/* If queue is full or skb not available, read to discard mailbox */
 	if (likely(skb_queue_len(&offload->skb_queue) <=
-		   offload->skb_queue_len_max))
-		skb = alloc_can_skb(offload->dev, &cf);
+		   offload->skb_queue_len_max)) {
+		if (offload->fd_enable)
+			skb = alloc_canfd_skb(offload->dev, &cf_fd);
+		else
+			skb = alloc_can_skb(offload->dev, &cf);
+	}
 
 	if (!skb) {
 		struct can_frame cf_overflow;
+		struct canfd_frame cf_fd_overflow;
 		u32 timestamp;
 
-		ret = offload->mailbox_read(offload, &cf_overflow,
-					    &timestamp, n);
+		if (offload->fd_enable)
+			ret = offload->mailbox_read(offload, &cf_fd_overflow,
+						    &timestamp, n);
+		else
+			ret = offload->mailbox_read(offload, &cf_overflow,
+						    &timestamp, n);
 		if (ret)
 			offload->dev->stats.rx_dropped++;
 
@@ -141,7 +159,10 @@ static struct sk_buff *can_rx_offload_offload_one(struct can_rx_offload *offload
 	}
 
 	cb = can_rx_offload_get_cb(skb);
-	ret = offload->mailbox_read(offload, cf, &cb->timestamp, n);
+	if (offload->fd_enable)
+		ret = offload->mailbox_read(offload, cf_fd, &cb->timestamp, n);
+	else
+		ret = offload->mailbox_read(offload, cf, &cb->timestamp, n);
 	if (!ret) {
 		kfree_skb(skb);
 		return NULL;
diff --git a/include/linux/can/rx-offload.h b/include/linux/can/rx-offload.h
index cb31683bbe15..306a807ba93f 100644
--- a/include/linux/can/rx-offload.h
+++ b/include/linux/can/rx-offload.h
@@ -23,7 +23,8 @@
 struct can_rx_offload {
 	struct net_device *dev;
 
-	unsigned int (*mailbox_read)(struct can_rx_offload *offload, struct can_frame *cf,
+	unsigned int (*mailbox_read)(struct can_rx_offload *offload,
+				     void *frame,
 				     u32 *timestamp, unsigned int mb);
 
 	struct sk_buff_head skb_queue;
@@ -34,6 +35,7 @@ struct can_rx_offload {
 
 	struct napi_struct napi;
 
+	bool fd_enable;
 	bool inc;
 };
 
-- 
2.17.1

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