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authorOliver Hartkopp <socketcan@hartkopp.net>2020-11-10 18:49:12 +0300
committerMarc Kleine-Budde <mkl@pengutronix.de>2020-11-20 14:05:14 +0300
commite8e73562ce0b24d691ad35df3de34b324248458f (patch)
treef9f15ecc59d9d8dc1348bc2e984059806aecea52 /include/linux/can
parent75191707c7f5299764f00c8d2e9996af662ac2dd (diff)
downloadlinux-e8e73562ce0b24d691ad35df3de34b324248458f.tar.xz
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.h25
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)