linux-stable.git/drivers/net/can/dev/netlink.c, branch linux-6.3.y

can: bittiming: can_changelink() pass extack down callstack

2023-02-06T12:57:26+00:00

This is a preparation patch.

In order to pass warning/error messages during netlink calls back to
user space, pass the extack struct down the callstack of
can_changelink(), the actual error messages will be added in the
following ptaches.

Link: https://lore.kernel.org/all/20230202110854.2318594-10-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde

can: netlink: can_changelink(): convert from netdev_err() to NL_SET_ERR_MSG_FMT()

2023-02-06T12:57:26+00:00

Since commit 51c352bdbcd2 ("netlink: add support for formatted extack
messages") formatted extack messages are supported to inform the user
space or warnings/errors during netlink calls.

Replace the netdev_err() by NL_SET_ERR_MSG_FMT() to better inform the
user about the problem. While there, use %u to print unsigned values
and improve error message a bit.

Link: https://lore.kernel.org/all/20230202110854.2318594-9-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde

can: netlink: can_validate(): validate sample point for CAN and CAN-FD

2023-02-06T12:57:26+00:00

The sample point is a value in tenths of a percent. Meaningful values
are between 0 and 1000. Invalid values are rejected and an error
message is returned to user space via netlink.

Link: https://lore.kernel.org/all/20230202110854.2318594-8-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde

can: netlink: dump bitrate 0 if can_priv::bittiming.bitrate is -1U

2022-07-03T09:34:24+00:00

Upcoming changes on slcan driver will require you to specify a bitrate
of value -1 to prevent the open_candev() from failing but at the same
time highlighting that it is a fake value. In this case the command
`ip --details -s -s link show' would print 4294967295 as the bitrate
value. The patch change this value in 0.

Link: https://lore.kernel.org/all/20220628163137.413025-5-dario.binacchi@amarulasolutions.com
Suggested-by: Marc Kleine-Budde 
Signed-off-by: Dario Binacchi 
Tested-by: Jeroen Hofstee 
Signed-off-by: Marc Kleine-Budde

can: netlink: allow configuring of fixed data bit rates without need for do_set_data_bittiming callback

2022-06-13T16:25:29+00:00

This patch is similar to 7e193a42c37c ("can: netlink: allow
configuring of fixed bit rates without need for do_set_bittiming
callback") but for data bit rates instead of bit rates.

Usually CAN devices support configurable data bit rates. The limits
are defined by struct can_priv::data_bittiming_const. Another way is
to implement the struct can_priv::do_set_data_bittiming callback.

If the bit rate is configured via netlink, the can_changelink()
function checks that either can_priv::data_bittiming_const or struct
can_priv::do_set_data_bittiming is implemented.

In commit 431af779256c ("can: dev: add CAN interface API for fixed
bitrates") an API for configuring bit rates on CAN interfaces that
only support fixed bit rates was added. The supported bit rates are
defined by struct can_priv::bitrate_const.

However the above mentioned commit forgot to add the struct
can_priv::data_bitrate_const to the check in can_changelink().

In order to avoid to implement a no-op can_priv::do_set_data_bittiming
callback on devices with fixed data bit rates, extend the check in
can_changelink() accordingly.

Link: https://lore.kernel.org/all/20220613143633.4151884-1-mkl@pengutronix.de
Fixes: 431af779256c ("can: dev: add CAN interface API for fixed bitrates")
Acked-by: Max Staudt 
Signed-off-by: Marc Kleine-Budde

can: netlink: allow configuring of fixed bit rates without need for do_set_bittiming callback

2022-06-11T15:08:17+00:00

Usually CAN devices support configurable bit rates. The limits are
defined by struct can_priv::bittiming_const. Another way is to
implement the struct can_priv::do_set_bittiming callback.

If the bit rate is configured via netlink, the can_changelink()
function checks that either can_priv::bittiming_const or struct
can_priv::do_set_bittiming is implemented.

In commit 431af779256c ("can: dev: add CAN interface API for fixed
bitrates") an API for configuring bit rates on CAN interfaces that
only support fixed bit rates was added. The supported bit rates are
defined by struct can_priv::bitrate_const.

However the above mentioned commit forgot to add the struct
can_priv::bitrate_const to the check in can_changelink().

In order to avoid to implement a no-op can_priv::do_set_bittiming
callback on devices with fixed bit rates, extend the check in
can_changelink() accordingly.

Link: https://lore.kernel.org/all/20220611144248.3924903-1-mkl@pengutronix.de
Fixes: 431af779256c ("can: dev: add CAN interface API for fixed bitrates")
Reported-by: Max Staudt 
Signed-off-by: Marc Kleine-Budde

can: netlink: report the CAN controller mode supported flags

2022-01-05T11:09:06+00:00

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 
Signed-off-by: Marc Kleine-Budde

can: dev: replace can_priv::ctrlmode_static by can_get_static_ctrlmode()

2022-01-05T11:09:05+00:00

The statically enabled features of a CAN controller can be retrieved
using below formula:

| u32 ctrlmode_static = priv->ctrlmode & ~priv->ctrlmode_supported;

As such, there is no need to store this information. This patch remove
the field ctrlmode_static of struct can_priv and provides, in
replacement, the inline function can_get_static_ctrlmode() which
returns the same value.

Link: https://lore.kernel.org/all/20211213160226.56219-2-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol 
Signed-off-by: Marc Kleine-Budde

can: netlink: add can_priv::do_get_auto_tdcv() to retrieve tdcv from device

2021-10-24T14:24:29+00:00

Some CAN device can measure the TDCV (Transmission Delay Compensation
Value) automatically for each transmitted CAN frames.

A callback function do_get_auto_tdcv() is added to retrieve that
value. This function is used only if CAN_CTRLMODE_TDC_AUTO is enabled
(if CAN_CTRLMODE_TDC_MANUAL is selected, the TDCV value is provided by
the user).

If the device does not support reporting of TDCV, do_get_auto_tdcv()
should be set to NULL and TDCV will not be reported by the netlink
interface.

On success, do_get_auto_tdcv() shall return 0. If the value can not be
measured by the device, for example because network is down or because
no frames were transmitted yet, can_priv::do_get_auto_tdcv() shall
return a negative error code (e.g. -EINVAL) to signify that the value
is not yet available. In such cases, TDCV is not reported by the
netlink interface.

Link: https://lore.kernel.org/all/20210918095637.20108-6-mailhol.vincent@wanadoo.fr
CC: Stefan Mätje 
Signed-off-by: Vincent Mailhol 
Signed-off-by: Marc Kleine-Budde

can: netlink: add interface for CAN-FD Transmitter Delay Compensation (TDC)

2021-10-24T14:24:29+00:00

Add the netlink interface for TDC parameters of struct can_tdc_const
and can_tdc.

Contrary to the can_bittiming(_const) structures for which there is
just a single IFLA_CAN(_DATA)_BITTMING(_CONST) entry per structure,
here, we create a nested entry IFLA_CAN_TDC. Within this nested entry,
additional IFLA_CAN_TDC_TDC* entries are added for each of the TDC
parameters of the newly introduced struct can_tdc_const and struct
can_tdc.

For struct can_tdc_const, these are:
        IFLA_CAN_TDC_TDCV_MIN
        IFLA_CAN_TDC_TDCV_MAX
        IFLA_CAN_TDC_TDCO_MIN
        IFLA_CAN_TDC_TDCO_MAX
        IFLA_CAN_TDC_TDCF_MIN
        IFLA_CAN_TDC_TDCF_MAX

For struct can_tdc, these are:
        IFLA_CAN_TDC_TDCV
        IFLA_CAN_TDC_TDCO
        IFLA_CAN_TDC_TDCF

This is done so that changes can be applied in the future to the
structures without breaking the netlink interface.

The TDC netlink logic works as follow:

 * CAN_CTRLMODE_FD is not provided:
    - if any TDC parameters are provided: error.

    - TDC parameters not provided: TDC parameters unchanged.

 * CAN_CTRLMODE_FD is provided and is false:
     - TDC is deactivated: both the structure and the
       CAN_CTRLMODE_TDC_{AUTO,MANUAL} flags are flushed.

 * CAN_CTRLMODE_FD provided and is true:
    - CAN_CTRLMODE_TDC_{AUTO,MANUAL} and tdc{v,o,f} not provided: call
      can_calc_tdco() to automatically decide whether TDC should be
      activated and, if so, set CAN_CTRLMODE_TDC_AUTO and uses the
      calculated tdco value.

    - CAN_CTRLMODE_TDC_AUTO and tdco provided: set
      CAN_CTRLMODE_TDC_AUTO and use the provided tdco value. Here,
      tdcv is illegal and tdcf is optional.

    - CAN_CTRLMODE_TDC_MANUAL and both of tdcv and tdco provided: set
      CAN_CTRLMODE_TDC_MANUAL and use the provided tdcv and tdco
      value. Here, tdcf is optional.

    - CAN_CTRLMODE_TDC_{AUTO,MANUAL} are mutually exclusive. Whenever
      one flag is turned on, the other will automatically be turned
      off. Providing both returns an error.

    - Combination other than the one listed above are illegal and will
      return an error.

N.B. above rules mean that whenever CAN_CTRLMODE_FD is provided, the
previous TDC values will be overwritten. The only option to reuse
previous TDC value is to not provide CAN_CTRLMODE_FD.

All the new parameters are defined as u32. This arbitrary choice is
done to mimic the other bittiming values with are also all of type
u32. An u16 would have been sufficient to hold the TDC values.

This patch completes below series (c.f. [1]):
  - commit 289ea9e4ae59 ("can: add new CAN FD bittiming parameters:
    Transmitter Delay Compensation (TDC)")
  - commit c25cc7993243 ("can: bittiming: add calculation for CAN FD
    Transmitter Delay Compensation (TDC)")

[1] https://lore.kernel.org/linux-can/20210224002008.4158-1-mailhol.vincent@wanadoo.fr/T/#t

Link: https://lore.kernel.org/all/20210918095637.20108-5-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol 
Signed-off-by: Marc Kleine-Budde