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| author |   Oliver Hartkopp <socketcan@hartkopp.net> | 2020-11-10 16:49:12 +0100 |
|---|---|---|
| committer |   Marc Kleine-Budde <mkl@pengutronix.de> | 2020-11-20 12:05:14 +0100 |
| commit | e8e73562ce0b24d691ad35df3de34b324248458f (patch) | |
| tree | f9f15ecc59d9d8dc1348bc2e984059806aecea52 /include/linux/can | |
| parent | can: update documentation for DLC usage in Classical CAN (diff) | |
| download | linux-dev-e8e73562ce0b24d691ad35df3de34b324248458f.tar.xz linux-dev-e8e73562ce0b24d691ad35df3de34b324248458f.zip | |
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>
Diffstat (limited to 'include/linux/can')
| -rw-r--r-- | include/linux/can/dev.h | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h index e767a96ae075..197a79535cc2 100644 --- a/include/linux/can/dev.h +++ b/include/linux/can/dev.h @@ -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) |