Commit e8e73562 authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by Marc Kleine-Budde
Browse files

can: drivers: introduce helpers to access Classical CAN DLC values 



This patch adds the following helper to functions to access Classical CAN DLC
values.

can_get_cc_dlc(): get the data length code for Classical CAN raw DLC access
can_frame_set_cc_len(): set len and len8_dlc value for Classical CAN raw DLC access

Signed-off-by: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/r/20201110154913.1404582-2-mkl@pengutronix.de


Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 75191707

include/linux/can/dev.h

+25 −0
Original line number Diff line number Diff line
@@ -170,6 +170,31 @@ static inline bool can_is_canfd_skb(const struct sk_buff *skb) 
	return skb->len == CANFD_MTU;

}



/* helper to get the data length code (DLC) for Classical CAN raw DLC access */

static inline u8 can_get_cc_dlc(const struct can_frame *cf, const u32 ctrlmode)

{

	/* return len8_dlc as dlc value only if all conditions apply */

	if ((ctrlmode & CAN_CTRLMODE_CC_LEN8_DLC) &&

	    (cf->len == CAN_MAX_DLEN) &&

	    (cf->len8_dlc > CAN_MAX_DLEN && cf->len8_dlc <= CAN_MAX_RAW_DLC))

		return cf->len8_dlc;



	/* return the payload length as dlc value */

	return cf->len;

}



/* helper to set len and len8_dlc value for Classical CAN raw DLC access */

static inline void can_frame_set_cc_len(struct can_frame *cf, const u8 dlc,

					const u32 ctrlmode)

{

	/* the caller already ensured that dlc is a value from 0 .. 15 */

	if (ctrlmode & CAN_CTRLMODE_CC_LEN8_DLC && dlc > CAN_MAX_DLEN)

		cf->len8_dlc = dlc;



	/* limit the payload length 'len' to CAN_MAX_DLEN */

	cf->len = can_cc_dlc2len(dlc);

}



/* helper to define static CAN controller features at device creation time */

static inline void can_set_static_ctrlmode(struct net_device *dev,

					   u32 static_mode)