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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: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/r/20201110154913.1404582-2-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Oliver Hartkopp 2020-11-10 16:49:12 +01:00 committed by Marc Kleine-Budde
parent 75191707c7
commit e8e73562ce

View File

@ -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)