[PATCH] can.h: canxl: support Remote Request Substitution bit access

[Oliver Hartkopp <socketcan@hartkopp.net>]

The Remote Request Substitution bit is a dominant bit ("0") in the CAN XL
frame. As some CAN XL controllers support to access this bit a new
CANXL_RRS value has been defined for the canxl_frame.flags element.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
---
 include/uapi/linux/can.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/can.h b/include/uapi/linux/can.h
index e78cbd85ce7c..42abf0679fb4 100644
--- a/include/uapi/linux/can.h
+++ b/include/uapi/linux/can.h
@@ -180,20 +180,21 @@ struct canfd_frame {
 };
 
 /*
  * defined bits for canxl_frame.flags
  *
- * The canxl_frame.flags element contains two bits CANXL_XLF and CANXL_SEC
+ * The canxl_frame.flags element contains three bits CANXL_[XLF|SEC|RRS]
  * and shares the relative position of the struct can[fd]_frame.len element.
  * The CANXL_XLF bit ALWAYS needs to be set to indicate a valid CAN XL frame.
  * As a side effect setting this bit intentionally breaks the length checks
  * for Classical CAN and CAN FD frames.
  *
  * Undefined bits in canxl_frame.flags are reserved and shall be set to zero.
  */
 #define CANXL_XLF 0x80 /* mandatory CAN XL frame flag (must always be set!) */
 #define CANXL_SEC 0x01 /* Simple Extended Content (security/segmentation) */
+#define CANXL_RRS 0x02 /* Remote Request Substitution */
 
 /* the 8-bit VCID is optionally placed in the canxl_frame.prio element */
 #define CANXL_VCID_OFFSET 16 /* bit offset of VCID in prio element */
 #define CANXL_VCID_VAL_MASK 0xFFUL /* VCID is an 8-bit value */
 #define CANXL_VCID_MASK (CANXL_VCID_VAL_MASK << CANXL_VCID_OFFSET)
-- 
2.45.2