[RFC PATCH 3/5] can: dev: add CAN XL support

[Oliver Hartkopp <socketcan@hartkopp.net>]

Extend the CAN device driver infrastructure to handle CAN XL frames.
This especially addresses the increased data length which is extended
to uint16 for CAN XL.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
---
 drivers/net/can/dev/rx-offload.c |  2 +-
 drivers/net/can/dev/skb.c        | 53 +++++++++++++++++++++++++++-----
 include/linux/can/skb.h          |  3 +-
 3 files changed, 48 insertions(+), 10 deletions(-)

diff --git a/drivers/net/can/dev/rx-offload.c b/drivers/net/can/dev/rx-offload.c
index a32a01c172d4..8505e547e922 100644
--- a/drivers/net/can/dev/rx-offload.c
+++ b/drivers/net/can/dev/rx-offload.c
@@ -245,11 +245,11 @@ unsigned int can_rx_offload_get_echo_skb(struct can_rx_offload *offload,
 					 unsigned int *frame_len_ptr)
 {
 	struct net_device *dev = offload->dev;
 	struct net_device_stats *stats = &dev->stats;
 	struct sk_buff *skb;
-	u8 len;
+	unsigned int len;
 	int err;
 
 	skb = __can_get_echo_skb(dev, idx, &len, frame_len_ptr);
 	if (!skb)
 		return 0;
diff --git a/drivers/net/can/dev/skb.c b/drivers/net/can/dev/skb.c
index 8bb62dd864c8..a849f503dcff 100644
--- a/drivers/net/can/dev/skb.c
+++ b/drivers/net/can/dev/skb.c
@@ -53,11 +53,12 @@ int can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
 	BUG_ON(idx >= priv->echo_skb_max);
 
 	/* check flag whether this packet has to be looped back */
 	if (!(dev->flags & IFF_ECHO) ||
 	    (skb->protocol != htons(ETH_P_CAN) &&
-	     skb->protocol != htons(ETH_P_CANFD))) {
+	     skb->protocol != htons(ETH_P_CANFD) &&
+	     skb->protocol != htons(ETH_P_CANXL))) {
 		kfree_skb(skb);
 		return 0;
 	}
 
 	if (!priv->echo_skb[idx]) {
@@ -86,12 +87,12 @@ int can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
 	return 0;
 }
 EXPORT_SYMBOL_GPL(can_put_echo_skb);
 
 struct sk_buff *
-__can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 *len_ptr,
-		   unsigned int *frame_len_ptr)
+__can_get_echo_skb(struct net_device *dev, unsigned int idx,
+		   unsigned int *len_ptr, unsigned int *frame_len_ptr)
 {
 	struct can_priv *priv = netdev_priv(dev);
 
 	if (idx >= priv->echo_skb_max) {
 		netdev_err(dev, "%s: BUG! Trying to access can_priv::echo_skb out of bounds (%u/max %u)\n",
@@ -104,16 +105,17 @@ __can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 *len_ptr,
 		 * length is supported on both CAN and CANFD frames.
 		 */
 		struct sk_buff *skb = priv->echo_skb[idx];
 		struct can_skb_priv *can_skb_priv = can_skb_prv(skb);
 		struct canfd_frame *cf = (struct canfd_frame *)skb->data;
+		unsigned int len = can_get_data_len(skb);
 
 		/* get the real payload length for netdev statistics */
 		if (cf->can_id & CAN_RTR_FLAG)
 			*len_ptr = 0;
 		else
-			*len_ptr = cf->len;
+			*len_ptr = len;
 
 		if (frame_len_ptr)
 			*frame_len_ptr = can_skb_priv->frame_len;
 
 		priv->echo_skb[idx] = NULL;
@@ -139,11 +141,11 @@ __can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 *len_ptr,
  */
 unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx,
 			      unsigned int *frame_len_ptr)
 {
 	struct sk_buff *skb;
-	u8 len;
+	unsigned int len;
 
 	skb = __can_get_echo_skb(dev, idx, &len, frame_len_ptr);
 	if (!skb)
 		return 0;
 
@@ -244,10 +246,41 @@ struct sk_buff *alloc_canfd_skb(struct net_device *dev,
 
 	return skb;
 }
 EXPORT_SYMBOL_GPL(alloc_canfd_skb);
 
+struct sk_buff *alloc_canxl_skb(struct net_device *dev,
+				struct canxl_frame **cfx)
+{
+	struct sk_buff *skb;
+
+	skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
+			       sizeof(struct canxl_frame));
+	if (unlikely(!skb)) {
+		*cfx = NULL;
+
+		return NULL;
+	}
+
+	skb->protocol = htons(ETH_P_CANXL);
+	skb->pkt_type = PACKET_BROADCAST;
+	skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+	skb_reset_mac_header(skb);
+	skb_reset_network_header(skb);
+	skb_reset_transport_header(skb);
+
+	can_skb_reserve(skb);
+	can_skb_prv(skb)->ifindex = dev->ifindex;
+	can_skb_prv(skb)->skbcnt = 0;
+
+	*cfx = skb_put_zero(skb, sizeof(struct canxl_frame));
+
+	return skb;
+}
+EXPORT_SYMBOL_GPL(alloc_canxl_skb);
+
 struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
 {
 	struct sk_buff *skb;
 
 	skb = alloc_can_skb(dev, cf);
@@ -291,20 +324,24 @@ static bool can_skb_headroom_valid(struct net_device *dev, struct sk_buff *skb)
 }
 
 /* Drop a given socketbuffer if it does not contain a valid CAN frame. */
 bool can_dropped_invalid_skb(struct net_device *dev, struct sk_buff *skb)
 {
-	const struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
 	struct can_priv *priv = netdev_priv(dev);
+	unsigned int len = can_get_data_len(skb);
 
 	if (skb->protocol == htons(ETH_P_CAN)) {
 		if (unlikely(skb->len != CAN_MTU ||
-			     cfd->len > CAN_MAX_DLEN))
+			     len > CAN_MAX_DLEN))
 			goto inval_skb;
 	} else if (skb->protocol == htons(ETH_P_CANFD)) {
 		if (unlikely(skb->len != CANFD_MTU ||
-			     cfd->len > CANFD_MAX_DLEN))
+			     len > CANFD_MAX_DLEN))
+			goto inval_skb;
+	} else if (skb->protocol == htons(ETH_P_CANXL)) {
+		if (unlikely(skb->len != CANXL_MTU ||
+			     len > CANXL_MAX_DLEN || len == 0))
 			goto inval_skb;
 	} else {
 		goto inval_skb;
 	}
 
diff --git a/include/linux/can/skb.h b/include/linux/can/skb.h
index d043bc4afd6d..72ee887a783a 100644
--- a/include/linux/can/skb.h
+++ b/include/linux/can/skb.h
@@ -18,11 +18,12 @@
 
 void can_flush_echo_skb(struct net_device *dev);
 int can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
 		     unsigned int idx, unsigned int frame_len);
 struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx,
-				   u8 *len_ptr, unsigned int *frame_len_ptr);
+				   unsigned int *len_ptr,
+				   unsigned int *frame_len_ptr);
 unsigned int __must_check can_get_echo_skb(struct net_device *dev,
 					   unsigned int idx,
 					   unsigned int *frame_len_ptr);
 void can_free_echo_skb(struct net_device *dev, unsigned int idx,
 		       unsigned int *frame_len_ptr);
-- 
2.30.2