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Commit 1e0625fa authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by Marc Kleine-Budde
Browse files

candev: add/update helpers for CAN FD 



- update sanity checks
- add DLC to length conversion helpers
  - can_dlc2len() - get data length from can_dlc with sanitized can_dlc
  - can_len2dlc() - map the sanitized data length to an appropriate DLC

Signed-off-by: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent e2d265d3

drivers/net/can/dev.c

+34 −1
Original line number Diff line number Diff line
@@ -33,6 +33,39 @@ MODULE_DESCRIPTION(MOD_DESC); 
MODULE_LICENSE("GPL v2");

MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");



/* CAN DLC to real data length conversion helpers */



static const u8 dlc2len[] = {0, 1, 2, 3, 4, 5, 6, 7,

			     8, 12, 16, 20, 24, 32, 48, 64};



/* get data length from can_dlc with sanitized can_dlc */

u8 can_dlc2len(u8 can_dlc)

{

	return dlc2len[can_dlc & 0x0F];

}

EXPORT_SYMBOL_GPL(can_dlc2len);



static const u8 len2dlc[] = {0, 1, 2, 3, 4, 5, 6, 7, 8,		/* 0 - 8 */

			     9, 9, 9, 9,			/* 9 - 12 */

			     10, 10, 10, 10,			/* 13 - 16 */

			     11, 11, 11, 11,			/* 17 - 20 */

			     12, 12, 12, 12,			/* 21 - 24 */

			     13, 13, 13, 13, 13, 13, 13, 13,	/* 25 - 32 */

			     14, 14, 14, 14, 14, 14, 14, 14,	/* 33 - 40 */

			     14, 14, 14, 14, 14, 14, 14, 14,	/* 41 - 48 */

			     15, 15, 15, 15, 15, 15, 15, 15,	/* 49 - 56 */

			     15, 15, 15, 15, 15, 15, 15, 15};	/* 57 - 64 */



/* map the sanitized data length to an appropriate data length code */

u8 can_len2dlc(u8 len)

{

	if (unlikely(len > 64))

		return 0xF;



	return len2dlc[len];

}

EXPORT_SYMBOL_GPL(can_len2dlc);



#ifdef CONFIG_CAN_CALC_BITTIMING

#define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */
@@ -454,7 +487,7 @@ EXPORT_SYMBOL_GPL(can_bus_off); 
static void can_setup(struct net_device *dev)

{

	dev->type = ARPHRD_CAN;

	dev->mtu = sizeof(struct can_frame);

	dev->mtu = CAN_MTU;

	dev->hard_header_len = 0;

	dev->addr_len = 0;

	dev->tx_queue_len = 10;

include/linux/can/dev.h

+25 −8
Original line number Diff line number Diff line
@@ -61,22 +61,39 @@ struct can_priv { 
 * To be used in the CAN netdriver receive path to ensure conformance with

 * ISO 11898-1 Chapter 8.4.2.3 (DLC field)

 */

#define get_can_dlc(i)	(min_t(__u8, (i), 8))

#define get_can_dlc(i)		(min_t(__u8, (i), CAN_MAX_DLC))

#define get_canfd_dlc(i)	(min_t(__u8, (i), CANFD_MAX_DLC))



/* Drop a given socketbuffer if it does not contain a valid CAN frame. */

static inline int can_dropped_invalid_skb(struct net_device *dev,

					  struct sk_buff *skb)

{

	const struct can_frame *cf = (struct can_frame *)skb->data;

	const struct canfd_frame *cfd = (struct canfd_frame *)skb->data;



	if (skb->protocol == htons(ETH_P_CAN)) {

		if (unlikely(skb->len != CAN_MTU ||

			     cfd->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))

			goto inval_skb;

	} else

		goto inval_skb;



	if (unlikely(skb->len != sizeof(*cf) || cf->can_dlc > 8)) {

	return 0;



inval_skb:

	kfree_skb(skb);

	dev->stats.tx_dropped++;

	return 1;

}



	return 0;

}

/* get data length from can_dlc with sanitized can_dlc */

u8 can_dlc2len(u8 can_dlc);



/* map the sanitized data length to an appropriate data length code */

u8 can_len2dlc(u8 len);



struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max);

void free_candev(struct net_device *dev);