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| author | Vincent Mailhol <mailhol.vincent@wanadoo.fr> | 2021-12-13 19:02:26 +0300 |
|---|---|---|
| committer | Marc Kleine-Budde <mkl@pengutronix.de> | 2022-01-05 14:09:06 +0300 |
| commit | 383f0993fc77152b0773c85ed69d6734baf9cb48 (patch) | |
| tree | bbef49e4d29286b0f421e62a44a245237d78a320 /include/uapi/linux | |
| parent | 5fe1be81efd28bf2afcac218f23118dca6b1b648 (diff) | |
| download | linux-383f0993fc77152b0773c85ed69d6734baf9cb48.tar.xz | |
can: netlink: report the CAN controller mode supported flags
Currently, the CAN netlink interface provides no easy ways to check
the capabilities of a given controller. The only method from the
command line is to try each CAN_CTRLMODE_* individually to check
whether the netlink interface returns an -EOPNOTSUPP error or not
(alternatively, one may find it easier to directly check the source
code of the driver instead...)
This patch introduces a method for the user to check both the
supported and the static capabilities. The proposed method introduces
a new IFLA nest: IFLA_CAN_CTRLMODE_EXT which extends the current
IFLA_CAN_CTRLMODE. This is done to guaranty a full forward and
backward compatibility between the kernel and the user land
applications.
The IFLA_CAN_CTRLMODE_EXT nest contains one single entry:
IFLA_CAN_CTRLMODE_SUPPORTED. Because this entry is only used in one
direction: kernel to userland, no new struct nla_policy are
introduced.
Below table explains how IFLA_CAN_CTRLMODE_SUPPORTED (hereafter:
"supported") and can_ctrlmode::flags (hereafter: "flags") allow us to
identify both the supported and the static capabilities, when masked
with any of the CAN_CTRLMODE_* bit flags:
supported & flags & Controller capabilities
CAN_CTRLMODE_* CAN_CTRLMODE_*
-----------------------------------------------------------------------
false false Feature not supported (always disabled)
false true Static feature (always enabled)
true false Feature supported but disabled
true true Feature supported and enabled
Link: https://lore.kernel.org/all/20211213160226.56219-5-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Diffstat (limited to 'include/uapi/linux')
| -rw-r--r-- | include/uapi/linux/can/netlink.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/include/uapi/linux/can/netlink.h b/include/uapi/linux/can/netlink.h index 75b85c60efb2..02ec32d69474 100644 --- a/include/uapi/linux/can/netlink.h +++ b/include/uapi/linux/can/netlink.h @@ -137,6 +137,7 @@ enum { IFLA_CAN_DATA_BITRATE_CONST, IFLA_CAN_BITRATE_MAX, IFLA_CAN_TDC, + IFLA_CAN_CTRLMODE_EXT, /* add new constants above here */ __IFLA_CAN_MAX, @@ -166,6 +167,18 @@ enum { IFLA_CAN_TDC_MAX = __IFLA_CAN_TDC - 1 }; +/* + * IFLA_CAN_CTRLMODE_EXT nest: controller mode extended parameters + */ +enum { + IFLA_CAN_CTRLMODE_UNSPEC, + IFLA_CAN_CTRLMODE_SUPPORTED, /* u32 */ + + /* add new constants above here */ + __IFLA_CAN_CTRLMODE, + IFLA_CAN_CTRLMODE_MAX = __IFLA_CAN_CTRLMODE - 1 +}; + /* u16 termination range: 1..65535 Ohms */ #define CAN_TERMINATION_DISABLED 0 |