From e70a3263a7eed768d5f947b8f2aff8d2a79c9d97 Mon Sep 17 00:00:00 2001 From: Vincent Mailhol Date: Tue, 19 Jul 2022 23:35:48 +0900 Subject: can: error: specify the values of data[5..7] of CAN error frames 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.fr Signed-off-by: Vincent Mailhol Signed-off-by: Marc Kleine-Budde --- include/uapi/linux/can/error.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'include/uapi/linux/can') 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 */ -- cgit v1.2.3 From 3e5c291c7942d0909a48bc5ec1b9bba136465166 Mon Sep 17 00:00:00 2001 From: Vincent Mailhol Date: Tue, 19 Jul 2022 23:35:49 +0900 Subject: can: add CAN_ERR_CNT flag to notify availability of error counter Add a dedicated flag in uapi/linux/can/error.h to notify the userland that fields data[6] and data[7] of the CAN error frame were respectively populated with the tx and rx error counters. For all driver tree-wide, set up this flags whenever needed. Link: https://lore.kernel.org/all/20220719143550.3681-12-mailhol.vincent@wanadoo.fr Signed-off-by: Vincent Mailhol Signed-off-by: Marc Kleine-Budde --- include/uapi/linux/can/error.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/uapi/linux/can') diff --git a/include/uapi/linux/can/error.h b/include/uapi/linux/can/error.h index a1000cb63063..b7c3efd9ff99 100644 --- a/include/uapi/linux/can/error.h +++ b/include/uapi/linux/can/error.h @@ -57,6 +57,8 @@ #define CAN_ERR_BUSOFF 0x00000040U /* bus off */ #define CAN_ERR_BUSERROR 0x00000080U /* bus error (may flood!) */ #define CAN_ERR_RESTARTED 0x00000100U /* controller restarted */ +#define CAN_ERR_CNT 0x00000200U /* TX error counter / data[6] */ + /* RX error counter / data[7] */ /* arbitration lost in bit ... / data[0] */ #define CAN_ERR_LOSTARB_UNSPEC 0x00 /* unspecified */ -- cgit v1.2.3 From 3f9c26210cf80ea8cb5dd901aba5feb77200b085 Mon Sep 17 00:00:00 2001 From: Vincent Mailhol Date: Tue, 19 Jul 2022 23:35:50 +0900 Subject: can: error: add definitions for the different CAN error thresholds Currently, drivers are using magic numbers to derive the CAN error states from the error counter. Add three macro declarations to remediate this. For reference, the error-active, error-passive and bus-off are defined in ISO 11898, section 12.1.4.2 "Error counting". Although ISO 11898 does not define error-warning state, this extra value is also commonly used and is thus also added. Link: https://lore.kernel.org/all/20220719143550.3681-13-mailhol.vincent@wanadoo.fr Signed-off-by: Vincent Mailhol Signed-off-by: Marc Kleine-Budde --- include/uapi/linux/can/error.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'include/uapi/linux/can') diff --git a/include/uapi/linux/can/error.h b/include/uapi/linux/can/error.h index b7c3efd9ff99..acc1ac393d2a 100644 --- a/include/uapi/linux/can/error.h +++ b/include/uapi/linux/can/error.h @@ -127,4 +127,17 @@ /* TX error counter / data[6] */ /* RX error counter / data[7] */ +/* CAN state thresholds + * + * Error counter Error state + * ----------------------------------- + * 0 - 95 Error-active + * 96 - 127 Error-warning + * 128 - 255 Error-passive + * 256 and greater Bus-off + */ +#define CAN_ERROR_WARNING_THRESHOLD 96 +#define CAN_ERROR_PASSIVE_THRESHOLD 128 +#define CAN_BUS_OFF_THRESHOLD 256 + #endif /* _UAPI_CAN_ERROR_H */ -- cgit v1.2.3