linux-stable.git/drivers/net/can/dev/dev.c, branch linux-5.15.y

can: dev: add generic function can_eth_ioctl_hwts()

2025-10-02T11:39:11+00:00

[ Upstream commit 90f942c5a6d775bad1be33ba214755314105da4a ]

Tools based on libpcap (such as tcpdump) expect the SIOCSHWTSTAMP
ioctl call to be supported. This is also specified in the kernel doc
[1]. The purpose of this ioctl is to toggle the hardware timestamps.

Currently, CAN devices which support hardware timestamping have those
always activated. can_eth_ioctl_hwts() is a dumb function that will
always succeed when requested to set tx_type to HWTSTAMP_TX_ON or
rx_filter to HWTSTAMP_FILTER_ALL.

[1] Kernel doc: Timestamping, section 3.1 "Hardware Timestamping
Implementation: Device Drivers"
Link: https://docs.kernel.org/networking/timestamping.html#hardware-timestamping-implementation-device-drivers

Signed-off-by: Vincent Mailhol 
Link: https://lore.kernel.org/all/20220727101641.198847-9-mailhol.vincent@wanadoo.fr
Signed-off-by: Marc Kleine-Budde 
Stable-dep-of: 38c0abad45b1 ("can: etas_es58x: populate ndo_change_mtu() to prevent buffer overflow")
Signed-off-by: Sasha Levin

can: dev: add generic function can_ethtool_op_get_ts_info_hwts()

2025-10-02T11:39:11+00:00

[ Upstream commit 7fb48d25b5ce3bc488dbb019bf1736248181de9a ]

Add function can_ethtool_op_get_ts_info_hwts(). This function will be
used by CAN devices with hardware TX/RX timestamping support to
implement ethtool_ops::get_ts_info. This function does not offer
support to activate/deactivate hardware timestamps at device level nor
support the filter options (which is currently the case for all CAN
devices with hardware timestamping support).

The fact that hardware timestamp can not be deactivated at hardware
level does not impact the userland. As long as the user do not set
SO_TIMESTAMPING using a setsockopt() or ioctl(), the kernel will not
emit TX timestamps (RX timestamps will still be reproted as it is the
case currently).

Drivers which need more fine grained control remains free to implement
their own function, but we foresee that the generic function
introduced here will be sufficient for the majority.

Signed-off-by: Vincent Mailhol 
Link: https://lore.kernel.org/all/20220727101641.198847-8-mailhol.vincent@wanadoo.fr
Signed-off-by: Marc Kleine-Budde 
Stable-dep-of: 38c0abad45b1 ("can: etas_es58x: populate ndo_change_mtu() to prevent buffer overflow")
Signed-off-by: Sasha Levin

can: dev: can_set_termination(): allow sleeping GPIOs

2024-12-14T18:51:31+00:00

commit ee1dfbdd8b4b6de85e96ae2059dc9c1bdb6b49b5 upstream.

In commit 6e86a1543c37 ("can: dev: provide optional GPIO based
termination support") GPIO based termination support was added.

For no particular reason that patch uses gpiod_set_value() to set the
GPIO. This leads to the following warning, if the systems uses a
sleeping GPIO, i.e. behind an I2C port expander:

| WARNING: CPU: 0 PID: 379 at /drivers/gpio/gpiolib.c:3496 gpiod_set_value+0x50/0x6c
| CPU: 0 UID: 0 PID: 379 Comm: ip Not tainted 6.11.0-20241016-1 #1 823affae360cc91126e4d316d7a614a8bf86236c

Replace gpiod_set_value() by gpiod_set_value_cansleep() to allow the
use of sleeping GPIOs.

Cc: Nicolai Buchwitz 
Cc: Lino Sanfilippo 
Cc: stable@vger.kernel.org
Reported-by: Leonard Göhrs 
Tested-by: Leonard Göhrs 
Fixes: 6e86a1543c37 ("can: dev: provide optional GPIO based termination support")
Link: https://patch.msgid.link/20241121-dev-fix-can_set_termination-v1-1-41fa6e29216d@pengutronix.de
Signed-off-by: Marc Kleine-Budde 
Signed-off-by: Greg Kroah-Hartman

can: do not increase rx statistics when generating a CAN rx error message frame

2024-12-14T18:51:25+00:00

[ Upstream commit 676068db69b847f06fe054fca15bf6b107bd24da ]

The CAN error message frames (i.e. error skb) are an interface
specific to socket CAN. The payload of the CAN error message frames
does not correspond to any actual data sent on the wire. Only an error
flag and a delimiter are transmitted when an error occurs (c.f. ISO
11898-1 section 10.4.4.2 "Error flag").

For this reason, it makes no sense to increment the rx_packets and
rx_bytes fields of struct net_device_stats because no actual payload
were transmitted on the wire.

This patch fixes all the CAN drivers.

Link: https://lore.kernel.org/all/20211207121531.42941-2-mailhol.vincent@wanadoo.fr
CC: Marc Kleine-Budde 
CC: Nicolas Ferre 
CC: Alexandre Belloni 
CC: Ludovic Desroches 
CC: Chandrasekar Ramakrishnan 
CC: Maxime Ripard 
CC: Chen-Yu Tsai 
CC: Jernej Skrabec 
CC: Appana Durga Kedareswara rao 
CC: Naga Sureshkumar Relli 
CC: Michal Simek 
CC: Stephane Grosjean 
Tested-by: Jimmy Assarsson  # kvaser
Signed-off-by: Vincent Mailhol 
Acked-by: Stefan Mätje  # esd_usb2
Tested-by: Stefan Mätje  # esd_usb2
Signed-off-by: Marc Kleine-Budde 
Stable-dep-of: 9e66242504f4 ("can: c_can: c_can_handle_bus_err(): update statistics if skb allocation fails")
Signed-off-by: Sasha Levin

can: dev: can_restart(): fix race condition between controller restart and netif_carrier_on()

2023-11-20T10:08:15+00:00

[ Upstream commit 6841cab8c4504835e4011689cbdb3351dec693fd ]

This race condition was discovered while updating the at91_can driver
to use can_bus_off(). The following scenario describes how the
converted at91_can driver would behave.

When a CAN device goes into BUS-OFF state, the driver usually
stops/resets the CAN device and calls can_bus_off().

This function sets the netif carrier to off, and (if configured by
user space) schedules a delayed work that calls can_restart() to
restart the CAN device.

The can_restart() function first checks if the carrier is off and
triggers an error message if the carrier is OK.

Then it calls the driver's do_set_mode() function to restart the
device, then it sets the netif carrier to on. There is a race window
between these two calls.

The at91 CAN controller (observed on the sama5d3, a single core 32 bit
ARM CPU) has a hardware limitation. If the device goes into bus-off
while sending a CAN frame, there is no way to abort the sending of
this frame. After the controller is enabled again, another attempt is
made to send it.

If the bus is still faulty, the device immediately goes back to the
bus-off state. The driver calls can_bus_off(), the netif carrier is
switched off and another can_restart is scheduled. This occurs within
the race window before the original can_restart() handler marks the
netif carrier as OK. This would cause the 2nd can_restart() to be
called with an OK netif carrier, resulting in an error message.

The flow of the 1st can_restart() looks like this:

can_restart()
    // bail out if netif_carrier is OK

    netif_carrier_ok(dev)
    priv->do_set_mode(dev, CAN_MODE_START)
        // enable CAN controller
        // sama5d3 restarts sending old message

        // CAN devices goes into BUS_OFF, triggers IRQ

// IRQ handler start
    at91_irq()
        at91_irq_err_line()
            can_bus_off()
                netif_carrier_off()
                schedule_delayed_work()
// IRQ handler end

    netif_carrier_on()

The 2nd can_restart() will be called with an OK netif carrier and the
error message will be printed.

To close the race window, first set the netif carrier to on, then
restart the controller. In case the restart fails with an error code,
roll back the netif carrier to off.

Fixes: 39549eef3587 ("can: CAN Network device driver and Netlink interface")
Link: https://lore.kernel.org/all/20231005-can-dev-fix-can-restart-v2-2-91b5c1fd922c@pengutronix.de
Reviewed-by: Vincent Mailhol 
Signed-off-by: Marc Kleine-Budde 
Signed-off-by: Sasha Levin

can: dev: can_restart(): don't crash kernel if carrier is OK

2023-11-20T10:08:15+00:00

[ Upstream commit fe5c9940dfd8ba0c73672dddb30acd1b7a11d4c7 ]

During testing, I triggered a can_restart() with the netif carrier
being OK [1]. The BUG_ON, which checks if the carrier is OK, results
in a fatal kernel crash. This is neither helpful for debugging nor for
a production system.

[1] The root cause is a race condition in can_restart() which will be
fixed in the next patch.

Do not crash the kernel, issue an error message instead, and continue
restarting the CAN device anyway.

Fixes: 39549eef3587 ("can: CAN Network device driver and Netlink interface")
Link: https://lore.kernel.org/all/20231005-can-dev-fix-can-restart-v2-1-91b5c1fd922c@pengutronix.de
Reviewed-by: Vincent Mailhol 
Signed-off-by: Marc Kleine-Budde 
Signed-off-by: Sasha Levin

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

net: introduce CAN specific pointer in the struct net_device

2021-02-24T22:32:15+00:00

Since 20dd3850bcf8 ("can: Speed up CAN frame receiption by using
ml_priv") the CAN framework uses per device specific data in the AF_CAN
protocol. For this purpose the struct net_device->ml_priv is used. Later
the ml_priv usage in CAN was extended for other users, one of them being
CAN_J1939.

Later in the kernel ml_priv was converted to an union, used by other
drivers. E.g. the tun driver started storing it's stats pointer.

Since tun devices can claim to be a CAN device, CAN specific protocols
will wrongly interpret this pointer, which will cause system crashes.
Mostly this issue is visible in the CAN_J1939 stack.

To fix this issue, we request a dedicated CAN pointer within the
net_device struct.

Reported-by: syzbot+5138c4dd15a0401bec7b@syzkaller.appspotmail.com
Fixes: 20dd3850bcf8 ("can: Speed up CAN frame receiption by using ml_priv")
Fixes: ffd956eef69b ("can: introduce CAN midlayer private and allocate it automatically")
Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
Fixes: 497a5757ce4e ("tun: switch to net core provided statistics counters")
Signed-off-by: Oleksij Rempel 
Link: https://lore.kernel.org/r/20210223070127.4538-1-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski

can: dev: export can_get_state_str() function

2021-01-27T09:01:46+00:00

The can_get_state_str() function is also relevant to the drivers. Export the
symbol and make it visible in the can/dev.h header.

Link: https://lore.kernel.org/r/20210119170355.12040-1-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol 
Signed-off-by: Marc Kleine-Budde

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2021-01-20T20:16:11+00:00

Conflicts:

drivers/net/can/dev.c
  commit 03f16c5075b2 ("can: dev: can_restart: fix use after free bug")
  commit 3e77f70e7345 ("can: dev: move driver related infrastructure into separate subdir")

  Code move.

drivers/net/dsa/b53/b53_common.c
 commit 8e4052c32d6b ("net: dsa: b53: fix an off by one in checking "vlan->vid"")
 commit b7a9e0da2d1c ("net: switchdev: remove vid_begin -> vid_end range from VLAN objects")

 Field rename.

Signed-off-by: Jakub Kicinski