linux-stable.git/drivers/net/can/dev, branch v5.15.78

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

2022-08-17T12:23:20+00:00

[ Upstream commit ec30c109391c5eac9b1d689a61e4bfed88148947 ]

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 
Signed-off-by: Sasha Levin

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

2022-08-17T12:23:20+00:00

[ Upstream commit 7e193a42c37cf40eba8ac5af2d5e8eeb8b9506f9 ]

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 
Signed-off-by: Sasha Levin

can: bittiming: can_fixup_bittiming(): change type of tseg1 and alltseg to unsigned int

2021-11-18T18:16:19+00:00

[ Upstream commit e346290439609a8ac67122418ca2efbad8d0a7e7 ]

All timing calculation is done with unsigned integers, so change type
of tseg1 and alltseg to unsigned int, too.

Link: https://lore.kernel.org/all/20211013130653.1513627-1-mkl@pengutronix.de
Link: https://github.com/linux-can/can-utils/pull/314
Reported-by: Gary Bisson 
Signed-off-by: Marc Kleine-Budde 
Signed-off-by: Sasha Levin

can: netlink: allow user to turn off unsupported features

2021-08-19T13:07:03+00:00

The sanity checks on the control modes will reject any request related
to an unsupported features, even turning it off.

Example on an interface which does not support CAN-FD:

$ ip link set can0 type can bitrate 500000 fd off
RTNETLINK answers: Operation not supported

This patch lets such command go through (but requests to turn on an
unsupported feature are, of course, still denied).

Link: https://lore.kernel.org/r/20210815033248.98111-2-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol 
Signed-off-by: Marc Kleine-Budde

can: dev: provide optional GPIO based termination support

2021-08-19T13:07:03+00:00

For CAN buses to work, a termination resistor has to be present at both
ends of the bus. This resistor is usually 120 Ohms, other values may be
required for special bus topologies.

This patch adds support for a generic GPIO based CAN termination. The
resistor value has to be specified via device tree, and it can only be
attached to or detached from the bus. By default the termination is not
active.

Link: https://lore.kernel.org/r/20210818071232.20585-4-o.rempel@pengutronix.de
Signed-off-by: Oleksij Rempel 
Signed-off-by: Marc Kleine-Budde

can: netlink: remove redundant check in can_validate()

2021-07-25T09:36:25+00:00

can_validate() does a first check:

|	if (is_can_fd) {
|		if (!data[IFLA_CAN_BITTIMING] || !data[IFLA_CAN_DATA_BITTIMING])
|			return -EOPNOTSUPP;
|	}

If that first if succeeds, we know that if is_can_fd is true then
data[IFLA_CAN_BITTIMING is set.

However, the next if switch does not leverage on above knowledge and
redoes the check:

| 	if (data[IFLA_CAN_DATA_BITTIMING]) {
|		if (!is_can_fd || !data[IFLA_CAN_BITTIMING])
|		                   ^~~~~~~~~~~~~~~~~~~~~~~~
| 			return -EOPNOTSUPP;
| 	}

This patch removes that redundant check.

Link: https://lore.kernel.org/r/20210603151550.140727-2-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol 
Signed-off-by: Marc Kleine-Budde

can: netlink: clear data_bittiming if FD is turned off

2021-07-25T09:36:25+00:00

When the FD is turned off through the netlink interface, the data bit
timing values still remain in data_bittiming and are displayed despite
of the feature being disabled.

Example:

| $ ip link set can0 type can bitrate 500000 dbitrate 2000000 fd on
| $ ip --details link show can0
| 1:  can0:  mtu 72 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 10
|     link/can  promiscuity 0 minmtu 0 maxmtu 0
|     can  state STOPPED restart-ms 0
| 	  bitrate 500000 sample-point 0.875
| 	  tq 12 prop-seg 69 phase-seg1 70 phase-seg2 20 sjw 1
| 	  ES582.1/ES584.1: tseg1 2..256 tseg2 2..128 sjw 1..128 brp 1..512 brp-inc 1
| 	  dbitrate 2000000 dsample-point 0.750
| 	  dtq 12 dprop-seg 14 dphase-seg1 15 dphase-seg2 10 dsjw 1
| 	  ES582.1/ES584.1: dtseg1 2..32 dtseg2 1..16 dsjw 1..8 dbrp 1..32 dbrp-inc 1
| 	  clock 80000000 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535
|
| $ ip link set can0 type can bitrate 500000 fd off
| $ ip --details link show can0
| 1:  can0:  mtu 16 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 10
|     link/can  promiscuity 0 minmtu 0 maxmtu 0
|     can state STOPPED restart-ms 0
| 	  bitrate 500000 sample-point 0.875
| 	  tq 12 prop-seg 69 phase-seg1 70 phase-seg2 20 sjw 1
| 	  ES582.1/ES584.1: tseg1 2..256 tseg2 2..128 sjw 1..128 brp 1..512 brp-inc 1
| 	  dbitrate 2000000 dsample-point 0.750
| 	  dtq 12 dprop-seg 14 dphase-seg1 15 dphase-seg2 10 dsjw 1
| 	  ES582.1/ES584.1: dtseg1 2..32 dtseg2 1..16 dsjw 1..8 dbrp 1..32 dbrp-inc 1
| 	  clock 80000000 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535

Remark: once FD is turned off, it is not possible to turn fd back on
and reuse the previously input data bit timing values:

| $ ip link set can0 type can bitrate 500000 fd on
| RTNETLINK answers: Operation not supported

This means that the user will need to re-configure the data bit timing
in order to turn fd on again.

Because old data bit timing values cannot be reused, this patch clears
priv->data_bit timing whenever FD is turned off. This way, the data
bit timing variables are not displayed anymore.

Link: https://lore.kernel.org/r/20210618081904.141114-2-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol 
Signed-off-by: Marc Kleine-Budde

can: rx-offload: can_rx_offload_threaded_irq_finish(): add new function to be called from threaded interrupt

2021-07-25T09:36:25+00:00

After reading all CAN frames from the controller in the IRQ handler
and storing them into a skb_queue, the driver calls napi_schedule().
In the napi poll function the skb from the skb_queue are then pushed
into the networking stack.

However if napi_schedule() is called from a threaded IRQ handler this
triggers the following error:

| NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #08!!!

To avoid this, create a new rx-offload
function (can_rx_offload_threaded_irq_finish()) with a call to
local_bh_disable()/local_bh_enable() around the napi_schedule() call.

Convert all drivers that call can_rx_offload_irq_finish() from
threaded IRQ context to can_rx_offload_threaded_irq_finish().

Link: https://lore.kernel.org/r/20210724204745.736053-4-mkl@pengutronix.de
Suggested-by: Daniel Glöckner 
Tested-by: Oleksij Rempel 
Signed-off-by: Marc Kleine-Budde

can: rx-offload: can_rx_offload_irq_finish(): directly call napi_schedule()

2021-07-25T09:36:25+00:00

Instead of calling can_rx_offload_schedule() call napi_schedule()
directly. As this was the last use of can_rx_offload_schedule() remove
this helper function.

Link: https://lore.kernel.org/r/20210724204745.736053-3-mkl@pengutronix.de
Tested-by: Oleksij Rempel 
Signed-off-by: Marc Kleine-Budde

can: rx-offload: add skb queue for use during ISR

2021-07-25T09:36:25+00:00

Adding a skb to the skb_queue in rx-offload requires to take a lock.

This commit avoids this by adding an unlocked skb queue that is
appended at the end of the ISR. Having one lock at the end of the ISR
should be OK as the HW is empty, not about to overflow.

Link: https://lore.kernel.org/r/20210724204745.736053-2-mkl@pengutronix.de
Tested-by: Oleksij Rempel 
Co-developed-by: Kurt Van Dijck 
Signed-off-by: Kurt Van Dijck 
Signed-off-by: Marc Kleine-Budde