kernel/linux.git/drivers/net/can/dev/dev.c, branch v6.19.11

can: dev: alloc_candev_mqs(): add missing default CAN capabilities

2026-01-16T17:06:56+00:00

The idea behind series 6c1f5146b214 ("Merge patch series "can: raw: better approach to instantly reject unsupported CAN frames"") is to set the capabilities of a CAN device (CAN-CC, CAN-FD, CAN-XL, and listen only) [1] and, based on these capabilities, reject unsupported CAN frames in the CAN-RAW protocol [2]. This works perfectly for CAN devices configured in CAN-FD or CAN-XL mode. CAN devices with static CAN control modes define their capabilities via can_set_static_ctrlmode() -> can_set_cap_info(). CAN devices configured by the user space for CAN-FD or CAN-XL set their capabilities via can_changelink() -> can_ctrlmode_changelink() -> can_set_cap_info(). However, in commit 166e87329ce6 ("can: propagate CAN device capabilities via ml_priv"), the capabilities of CAN devices are not initialized. This results in CAN-RAW rejecting all CAN frames on devices directly after ifup if the user space has not changed the CAN control mode. Fix this problem by setting the default capabilities to CAN-CC in alloc_candev_mqs() as soon as the CAN specific ml_priv is allocated. [1] commit 166e87329ce6 ("can: propagate CAN device capabilities via ml_priv") [2] commit faba5860fcf9 ("can: raw: instantly reject disabled CAN frames") Fixes: 166e87329ce6 ("can: propagate CAN device capabilities via ml_priv") Acked-by: Oliver Hartkopp Tested-by: Oliver Hartkopp Link: https://patch.msgid.link/20260116-can_add_missing_set_caps-v1-1-7525126d8b20@pengutronix.de [mkl: fix typo in subject] Signed-off-by: Marc Kleine-Budde

can: propagate CAN device capabilities via ml_priv

2026-01-15T08:52:04+00:00

Commit 1a620a723853 ("can: raw: instantly reject unsupported CAN frames") caused a sequence of dependency and linker fixes. Instead of accessing CAN device internal data structures which caused the dependency problems this patch introduces capability information into the CAN specific ml_priv data which is accessible from both sides. With this change the CAN network layer can check the required features and the decoupling of the driver layer and network layer is restored. Fixes: 1a620a723853 ("can: raw: instantly reject unsupported CAN frames") Cc: Marc Kleine-Budde Cc: Arnd Bergmann Cc: Vincent Mailhol Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20260109144135.8495-3-socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde

can: netlink: add CAN_CTRLMODE_XL_TMS flag

2025-11-26T10:20:43+00:00

The Transceiver Mode Switching (TMS) indicates whether the CAN XL controller shall use the PWM or NRZ encoding during the data phase. The term "transceiver mode switching" is used in both ISO 11898-1 and CiA 612-2 (although only the latter one uses the abbreviation TMS). We adopt the same naming convention here for consistency. Add the CAN_CTRLMODE_XL_TMS flag to the list of the CAN control modes. Add can_validate_xl_flags() to check the coherency of the TMS flag. That function will be reused in upcoming changes to validate the other CAN XL flags. Signed-off-by: Vincent Mailhol Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20251126-canxl-v8-6-e7e3eb74f889@pengutronix.de Signed-off-by: Marc Kleine-Budde

can: netlink: add initial CAN XL support

2025-11-26T10:20:43+00:00

CAN XL uses bittiming parameters different from Classical CAN and CAN FD. Thus, all the data bittiming parameters, including TDC, need to be duplicated for CAN XL. Add the CAN XL netlink interface for all the features which are common with CAN FD. Any new CAN XL specific features are added later on. The first time CAN XL is activated, the MTU is set by default to CANXL_MAX_MTU. The user may then configure a custom MTU within the CANXL_MIN_MTU to CANXL_MAX_MTU range, in which case, the custom MTU value will be kept as long as CAN XL remains active. Signed-off-by: Vincent Mailhol Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20251126-canxl-v8-5-e7e3eb74f889@pengutronix.de Signed-off-by: Marc Kleine-Budde

can: netlink: add CAN_CTRLMODE_RESTRICTED

2025-11-26T10:20:43+00:00

ISO 11898-1:2024 adds a new restricted operation mode. This mode is added as a mandatory feature for nodes which support CAN XL and is retrofitted as optional for legacy nodes (i.e. the ones which only support Classical CAN and CAN FD). The restricted operation mode is nearly the same as the listen only mode: the node can not send data frames or remote frames and can not send dominant bits if an error occurs. The only exception is that the node shall still send the acknowledgment bit. A second niche exception is that the node may still send a data frame containing a time reference message if the node is a primary time provider, but because the time provider feature is not yet implemented in the kernel, this second exception is not relevant to us at the moment. Add the CAN_CTRLMODE_RESTRICTED control mode flag and update the can_dev_dropped_skb() helper function accordingly. Finally, bail out if both CAN_CTRLMODE_LISTENONLY and CAN_CTRLMODE_RESTRICTED are provided. Signed-off-by: Vincent Mailhol Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20251126-canxl-v8-4-e7e3eb74f889@pengutronix.de Signed-off-by: Marc Kleine-Budde

can: dev: can_get_ctrlmode_str: use capitalized ctrlmode strings

2025-11-26T10:20:43+00:00

Unify the ctrlmode related strings to the command line options of the 'ip' tool from the iproute2 package. The capitalized strings are also shown when the detailed interface configuration is printed by 'ip'. Suggested-by: Stephane Grosjean Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20251126-canxl-v8-1-e7e3eb74f889@pengutronix.de Signed-off-by: Marc Kleine-Budde

can: convert generic HW timestamp ioctl to ndo_hwtstamp callbacks

2025-10-31T12:12:18+00:00

Can has generic implementation of ndo_eth_ioctl which implements only HW timestamping commands. Implement generic ndo_hwtstamp callbacks and use it in drivers instead of generic ioctl interface. Signed-off-by: Vadim Fedorenko Reviewed-by: Kory Maincent Reviewed-by: Vincent Mailhol Link: https://patch.msgid.link/20251029231620.1135640-2-vadim.fedorenko@linux.dev Signed-off-by: Marc Kleine-Budde

can: treewide: remove can_change_mtu()

2025-10-17T07:57:13+00:00

can_change_mtu() became obsolete by commit 23049938605b ("can: populate the minimum and maximum MTU values"). Now that net_device->min_mtu and net_device->max_mtu are populated, all the checks are already done by dev_validate_mtu() in net/core/dev.c. Remove the net_device_ops->ndo_change_mtu() callback of all the physical interfaces, then remove can_change_mtu(). Only keep the vcan_change_mtu() and vxcan_change_mtu() because the virtual interfaces use their own different MTU logic. The only functional change this patch introduces is that now the user will be able to change the MTU even if the interface is up. This does not matter for Classical CAN and CAN FD because their MTU range is composed of only one value, respectively CAN_MTU and CANFD_MTU. For the upcoming CAN XL, the MTU will be configurable within the CANXL_MIN_MTU to CANXL_MAX_MTU range at any time, even if the interface is up. This is consistent with the other net protocols and does not contradict ISO 11898-1:2024 as having a modifiable MTU is a kernel extension. Signed-off-by: Vincent Mailhol Link: https://patch.msgid.link/20251003-remove-can_change_mtu-v1-1-337f8bc21181@kernel.org Signed-off-by: Marc Kleine-Budde

can: dev: add can_get_ctrlmode_str()

2025-09-24T15:09:47+00:00

In an effort to give more human readable messages when errors occur because of conflicting options, it can be useful to convert the CAN control mode flags into text. Add a function which converts the first set CAN control mode into a human readable string. The reason to only convert the first one is to simplify edge cases: imagine that there are several invalid control modes, we would just return the first invalid one to the user, thus not having to handle complex string concatenation. The user can then solve the first problem, call the netlink interface again and see the next issue. People who wish to enumerate all the control modes can still do so by, for example, using this new function in a for_each_set_bit() loop. Signed-off-by: Vincent Mailhol Link: https://patch.msgid.link/20250923-canxl-netlink-prep-v4-19-e720d28f66fe@kernel.org Signed-off-by: Marc Kleine-Budde

can: populate the minimum and maximum MTU values

2025-09-24T15:04:22+00:00

By populating: net_device->min_mtu and net_device->max_mtu the net core infrastructure will automatically: 1. validate that the user's inputs are in range. 2. report those min and max MTU values through the netlink interface. Add can_set_default_mtu() which sets the default mtu value as well as the minimum and maximum values. The logic for the default mtu value remains unchanged: - CANFD_MTU if the device has a static CAN_CTRLMODE_FD. - CAN_MTU otherwise. Call can_set_default_mtu() each time the CAN_CTRLMODE_FD is modified. This will guarantee that the MTU value is always consistent with the control mode flags. With this, the checks done in can_change_mtu() become fully redundant and will be removed in an upcoming change and it is now possible to confirm the minimum and maximum MTU values on a physical CAN interface by doing: $ ip --details link show can0 The virtual interfaces (vcan and vxcan) are not impacted by this change. Signed-off-by: Vincent Mailhol Link: https://patch.msgid.link/20250923-can-fix-mtu-v3-3-581bde113f52@kernel.org [mkl: squashed https://patch.msgid.link/20250924143644.17622-2-mailhol@kernel.org] Signed-off-by: Marc Kleine-Budde