From: Vincent Mailhol mailhol.vincent@wanadoo.fr
[ Upstream commit e70a3263a7eed768d5f947b8f2aff8d2a79c9d97 ]
Currently, data[5..7] of struct can_frame, when used as a CAN error frame, are defined as being "controller specific". Device specific behaviours are problematic because it prevents someone from writing code which is portable between devices.
As a matter of fact, data[5] is never used, data[6] is always used to report TX error counter and data[7] is always used to report RX error counter. can-utils also relies on this.
This patch updates the comment in the uapi header to specify that data[5] is reserved (and thus should not be used) and that data[6..7] are used for error counters.
Fixes: 0d66548a10cb ("[CAN]: Add PF_CAN core module") Link: https://lore.kernel.org/all/20220719143550.3681-11-mailhol.vincent@wanadoo.f... Signed-off-by: Vincent Mailhol mailhol.vincent@wanadoo.fr Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de Signed-off-by: Sasha Levin sashal@kernel.org --- include/uapi/linux/can/error.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/can/error.h b/include/uapi/linux/can/error.h index 34633283de64..a1000cb63063 100644 --- a/include/uapi/linux/can/error.h +++ b/include/uapi/linux/can/error.h @@ -120,6 +120,9 @@ #define CAN_ERR_TRX_CANL_SHORT_TO_GND 0x70 /* 0111 0000 */ #define CAN_ERR_TRX_CANL_SHORT_TO_CANH 0x80 /* 1000 0000 */
-/* controller specific additional information / data[5..7] */ +/* data[5] is reserved (do not use) */ + +/* TX error counter / data[6] */ +/* RX error counter / data[7] */
#endif /* _UAPI_CAN_ERROR_H */