summaryrefslogtreecommitdiff
path: root/include/linux/can
AgeCommit message (Collapse)Author
2025-11-29can: Kconfig: select CAN driver infrastructure by defaultOliver Hartkopp
The CAN bus support enabled with CONFIG_CAN provides a socket-based access to CAN interfaces. With the introduction of the latest CAN protocol CAN XL additional configuration status information needs to be exposed to the network layer than formerly provided by standard Linux network drivers. This requires the CAN driver infrastructure to be selected by default. As the CAN network layer can only operate on CAN interfaces anyway all distributions and common default configs enable at least one CAN driver. So selecting CONFIG_CAN_DEV when CONFIG_CAN is selected by the user has no effect on established configurations but solves potential build issues when CONFIG_CAN[_XXX]=y is set together with CANFIG_CAN_DEV=m Fixes: 1a620a723853 ("can: raw: instantly reject unsupported CAN frames") Reported-by: Vincent Mailhol <mailhol@kernel.org> Closes: https://lore.kernel.org/all/CAMZ6RqL_nGszwoLPXn1Li8op-ox4k3Hs6p=Hw6+w0W=DTtobPw@mail.gmail.com/ Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202511280531.YnWW2Rxc-lkp@intel.com/ Closes: https://lore.kernel.org/oe-kbuild-all/202511280842.djCQ0N0O-lkp@intel.com/ Closes: https://lore.kernel.org/oe-kbuild-all/202511282325.uVQFRTkA-lkp@intel.com/ Closes: https://lore.kernel.org/oe-kbuild-all/202511291520.guIE1QHj-lkp@intel.com/ Suggested-by: Marc Kleine-Budde <mkl@pengutronix.de> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://patch.msgid.link/20251129090500.17484-1-socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-11-26can: calc_bittiming: add PWM calculationVincent Mailhol
Perform the PWM calculation according to CiA recommendations. Note that for databitrates greater than 5 MBPS, tqmin is less than CAN_PWM_NS_MAX (which is defined to 200 nano seconds), consequently, the result of the division: DIV_ROUND_UP(xl_ns, CAN_PWM_NS_MAX) is one and thus the for loop automatically stops on the first iteration giving a single PWM symbol per bit as expected. Because of that, there is no actual need for a separate conditional branch for when the databitrate is greater than 5 MBPS. Signed-off-by: Vincent Mailhol <mailhol@kernel.org> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://patch.msgid.link/20251126-canxl-v8-10-e7e3eb74f889@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-11-26can: bittiming: add PWM validationVincent Mailhol
Add can_validate_pwm() to validate the values pwms, pwml and pwml. Error messages are added to each of the checks to inform the user on what went wrong. Refer to those error messages to understand the validation logic. The boundary values CAN_PWM_DECODE_NS (the transceiver minimum decoding margin) and CAN_PWM_NS_MAX (the maximum PWM symbol duration) are hardcoded for the moment. Note that a transceiver capable of bitrates higher than 20 Mbps may be able to handle a CAN_PWM_DECODE_NS below 5 ns. If such transceivers become commercially available, this code could be revisited to make this parameter configurable. For now, leave it static. Signed-off-by: Vincent Mailhol <mailhol@kernel.org> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://patch.msgid.link/20251126-canxl-v8-9-e7e3eb74f889@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-11-26can: bittiming: add PWM parametersVincent Mailhol
In CAN XL, higher data bit rates require the CAN transceiver to switch its operation mode to use Pulse-Width Modulation (PWM) transmission mode instead of the classic dominant/recessive transmission mode. The PWM parameters are: - PWMS: pulse width modulation short phase - PWML: pulse width modulation long phase - PWMO: pulse width modulation offset CiA 612-2 specifies PWMS and PWML to be at least 1 (arguably, PWML shall be at least 2 to respect the PWMS < PWML rule). PWMO's minimum is expected to always be zero. It is added more for consistency than anything else. Add struct can_pwm_const so that the different devices can provide their minimum and maximum values. When TMS is on, the runtime PWMS, PWML and PWMO are needed (either calculated or provided by the user): add struct can_pwm to store these. TDC and PWM can not be used at the same time (TDC can only be used when TMS is off and PWM only when TMS is on). struct can_pwm is thus put together with struct can_tdc inside a union to save some space. The netlink logic will be added in an upcoming change. Signed-off-by: Vincent Mailhol <mailhol@kernel.org> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://patch.msgid.link/20251126-canxl-v8-8-e7e3eb74f889@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-11-26can: dev: can_dev_dropped_skb: drop CC/FD frames in CANXL-only modeOliver Hartkopp
The error-signalling (ES) is a mandatory functionality for CAN CC and CAN FD to report CAN frame format violations by sending an error-frame signal on the bus. A so-called 'mixed-mode' is intended to have (XL-tolerant) CAN FD nodes and CAN XL nodes on one CAN segment, where the FD-controllers can talk CC/FD and the XL-controllers can talk CC/FD/XL. This mixed-mode utilizes the error-signalling for sending CC/FD/XL frames. The CANXL-only mode disables the error-signalling in the CAN XL controller. This mode does not allow CC/FD frames to be sent but additionally offers a CAN XL transceiver mode switching (TMS). Configured with CAN_CTRLMODE_FD and CAN_CTRLMODE_XL this leads to: FD=0 XL=0 CC-only mode (ES=1) FD=1 XL=0 FD/CC mixed-mode (ES=1) FD=1 XL=1 XL/FD/CC mixed-mode (ES=1) FD=0 XL=1 XL-only mode (ES=0, TMS optional) The helper function can_dev_in_xl_only_mode() determines the required value to disable error signalling in the CAN XL controller. Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://patch.msgid.link/20251126-canxl-v8-7-e7e3eb74f889@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-11-26can: netlink: add initial CAN XL supportVincent Mailhol
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 <mailhol@kernel.org> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://patch.msgid.link/20251126-canxl-v8-5-e7e3eb74f889@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-11-26can: netlink: add CAN_CTRLMODE_RESTRICTEDVincent Mailhol
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 <mailhol@kernel.org> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://patch.msgid.link/20251126-canxl-v8-4-e7e3eb74f889@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-11-26can: dev: can_dev_dropped_skb: drop CAN FD skbs if FD is offVincent Mailhol
Currently, the CAN FD skb validation logic is based on the MTU: the interface is deemed FD capable if and only if its MTU is greater or equal to CANFD_MTU. This logic is showing its limit with the introduction of CAN XL. For example, consider the two scenarios below: 1. An interface configured with CAN FD on and CAN XL on 2. An interface configured with CAN FD off and CAN XL on In those two scenarios, the interfaces would have the same MTU: CANXL_MTU making it impossible to differentiate which one has CAN FD turned on and which one has it off. Because of the limitation, the only non-UAPI-breaking workaround is to do the check at the device level using the can_priv->ctrlmode flags. Unfortunately, the virtual interfaces (vcan, vxcan), which do not have a can_priv, are left behind. Add a check on the CAN_CTRLMODE_FD flag in can_dev_dropped_skb() and drop FD frames whenever the feature is turned off. Signed-off-by: Vincent Mailhol <mailhol@kernel.org> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://patch.msgid.link/20251126-canxl-v8-3-e7e3eb74f889@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-11-26can: bittiming: apply NL_SET_ERR_MSG() to can_calc_bittiming()Vincent Mailhol
When CONFIG_CAN_CALC_BITTIMING is disabled, the can_calc_bittiming() functions can not be used and the user needs to provide all the bittiming parameters. Currently, can_calc_bittiming() prints an error message to the kernel log. Instead use NL_SET_ERR_MSG() to make it return the error message through the netlink interface so that the user can directly see it. Signed-off-by: Vincent Mailhol <mailhol@kernel.org> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://patch.msgid.link/20251126-canxl-v8-2-e7e3eb74f889@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-10-31can: convert generic HW timestamp ioctl to ndo_hwtstamp callbacksVadim Fedorenko
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 <vadim.fedorenko@linux.dev> Reviewed-by: Kory Maincent <kory.maincent@bootlin.com> Reviewed-by: Vincent Mailhol <mailhol@kernel.org> Link: https://patch.msgid.link/20251029231620.1135640-2-vadim.fedorenko@linux.dev Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-10-17can: treewide: remove can_change_mtu()Vincent Mailhol
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 <mailhol@kernel.org> Link: https://patch.msgid.link/20251003-remove-can_change_mtu-v1-1-337f8bc21181@kernel.org Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-09-24can: dev: add can_get_ctrlmode_str()Vincent Mailhol
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 <mailhol@kernel.org> Link: https://patch.msgid.link/20250923-canxl-netlink-prep-v4-19-e720d28f66fe@kernel.org Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-09-24can: calc_bittiming: make can_calc_tdco() FD agnosticVincent Mailhol
can_calc_tdco() uses the CAN_CTRLMODE_FD_TDC_MASK and CAN_CTRLMODE_TDC_AUTO macros making it specific to CAN FD. Add the tdc mask to the function parameter list. The value of the tdc auto flag can then be derived from that mask and stored in a local variable. This way, the function becomes CAN FD agnostic and can be reused later on for the CAN XL TDC. Signed-off-by: Vincent Mailhol <mailhol@kernel.org> Link: https://patch.msgid.link/20250923-canxl-netlink-prep-v4-18-e720d28f66fe@kernel.org Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-09-24can: netlink: add can_validate_tdc()Vincent Mailhol
Factorise the TDC validation out of can_validate() and move it in the new can_validate_tdc() function. This is a preparation patch for the introduction of CAN XL because this TDC validation will be reused later on. Signed-off-by: Vincent Mailhol <mailhol@kernel.org> Link: https://patch.msgid.link/20250923-canxl-netlink-prep-v4-5-e720d28f66fe@kernel.org Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-09-24can: dev: make can_get_relative_tdco() FD agnostic and move it to bittiming.hVincent Mailhol
can_get_relative_tdco() needs to access can_priv->fd making it specific to CAN FD. Change the function parameter from struct can_priv to struct data_bittiming_params. This way, the function becomes CAN FD agnostic and can be reused later on for the CAN XL TDC. Now that we dropped the dependency on struct can_priv, also move can_get_relative_tdco() back to bittiming.h where it was meant to belong to. Signed-off-by: Vincent Mailhol <mailhol@kernel.org> Link: https://patch.msgid.link/20250923-canxl-netlink-prep-v4-2-e720d28f66fe@kernel.org Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-09-24can: dev: move struct data_bittiming_params to linux/can/bittiming.hVincent Mailhol
In commit b803c4a4f788 ("can: dev: add struct data_bittiming_params to group FD parameters"), struct data_bittiming_params was put into linux/can/dev.h. This structure being a collection of bittiming parameters, on second thought, bittiming.h is actually a better location. This way, users of struct data_bittiming_params will not have to forcefully include linux/can/dev.h thus removing some complexity and reducing the risk of circular dependencies in headers. Move struct data_bittiming_params from linux/can/dev.h to linux/can/bittiming.h. Signed-off-by: Vincent Mailhol <mailhol@kernel.org> Link: https://patch.msgid.link/20250923-canxl-netlink-prep-v4-1-e720d28f66fe@kernel.org Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-09-24can: populate the minimum and maximum MTU valuesVincent Mailhol
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 <mailhol@kernel.org> 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 <mkl@pengutronix.de>
2025-09-23can: dev: turn can_set_static_ctrlmode() into a non-inline functionVincent Mailhol
can_set_static_ctrlmode() is declared as a static inline. But it is only called in the probe function of the devices and so does not really benefit from any kind of optimization. Transform it into a "normal" function by moving it to drivers/net/can/dev/dev.c Signed-off-by: Vincent Mailhol <mailhol@kernel.org> Link: https://patch.msgid.link/20250923-can-fix-mtu-v3-2-581bde113f52@kernel.org Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-09-13can: peak: Modification of references to email accounts being deletedStéphane Grosjean
With the upcoming deletion of @peak-system.com accounts and following the acquisition of PEAK-System and its brand by HMS-Networks, this fix aims to migrate all address references to @hms-networks.com, as well as to map my personal committer addresses to author addresses, while taking the opportunity to correct the accent on the first ‘e’ of my first name. Signed-off-by: Stéphane Grosjean <stephane.grosjean@hms-networks.com> Link: https://patch.msgid.link/20250912081820.86314-1-stephane.grosjean@free.fr Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-06-10can: bittiming: rename can_tdc_is_enabled() into can_fd_tdc_is_enabled()Vincent Mailhol
With the introduction of CAN XL, a new can_xl_tdc_is_enabled() helper function will be introduced later on. Rename can_tdc_is_enabled() into can_fd_tdc_is_enabled() to make it more explicit that this helper is meant for CAN FD. Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Link: https://patch.msgid.link/20241112165118.586613-11-mailhol.vincent@wanadoo.fr Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-06-10can: bittiming: rename CAN_CTRLMODE_TDC_MASK into CAN_CTRLMODE_FD_TDC_MASKVincent Mailhol
With the introduction of CAN XL, a new CAN_CTRLMODE_XL_TDC_MASK will be introduced later on. Because CAN_CTRLMODE_TDC_MASK is not part of the uapi, rename it to CAN_CTRLMODE_FD_TDC_MASK to make it more explicit that this mask is meant for CAN FD. Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Link: https://patch.msgid.link/20241112165118.586613-10-mailhol.vincent@wanadoo.fr Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-05-21can: dev: add struct data_bittiming_params to group FD parametersVincent Mailhol
This is a preparation patch for the introduction of CAN XL. CAN FD and CAN XL uses similar bittiming parameters. Add one level of nesting for all the CAN FD parameters. Typically: priv->can.data_bittiming; becomes: priv->can.fd.data_bittiming; This way, the CAN XL equivalent (to be introduced later) would be: priv->can.xl.data_bittiming; Add the new struct data_bittiming_params which contains all the data bittiming parameters, including the TDC and the callback functions. This done, update all the CAN FD drivers to make use of the new layout. Acked-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Link: https://patch.msgid.link/20250501171213.2161572-2-mailhol.vincent@wanadoo.fr [mkl: fix rcar_canfd] Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2024-07-15net: Add struct kernel_ethtool_ts_infoKory Maincent
In prevision to add new UAPI for hwtstamp we will be limited to the struct ethtool_ts_info that is currently passed in fixed binary format through the ETHTOOL_GET_TS_INFO ethtool ioctl. It would be good if new kernel code already started operating on an extensible kernel variant of that structure, similar in concept to struct kernel_hwtstamp_config vs struct hwtstamp_config. Since struct ethtool_ts_info is in include/uapi/linux/ethtool.h, here we introduce the kernel-only structure in include/linux/ethtool.h. The manual copy is then made in the function called by ETHTOOL_GET_TS_INFO. Acked-by: Shannon Nelson <shannon.nelson@amd.com> Acked-by: Alexandra Winter <wintera@linux.ibm.com> Signed-off-by: Kory Maincent <kory.maincent@bootlin.com> Link: https://patch.msgid.link/20240709-feature_ptp_netnext-v17-6-b5317f50df2a@bootlin.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-10-05can: dev: add can_state_get_by_berr_counter() to return the CAN state based ↵Marc Kleine-Budde
on the current error counters Some CAN controllers do not have a register that contains the current CAN state, but only a register that contains the error counters. Introduce a new function can_state_get_by_berr_counter() that returns the current TX and RX state depending on the provided CAN bit error counters. Link: https://lore.kernel.org/all/20231005-at91_can-rx_offload-v2-1-9987d53600e0@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2023-07-28can: rx-offload: add can_rx_offload_get_echo_skb_queue_tail()Marc Kleine-Budde
Add can_rx_offload_get_echo_skb_queue_tail(). This function addds the echo skb at the end of rx-offload the queue. This is intended for devices without timestamp support. Link: https://lore.kernel.org/all/20230718-gs_usb-rx-offload-v2-2-716e542d14d5@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2023-07-28can: rx-offload: rename rx_offload_get_echo_skb() -> ↵Marc Kleine-Budde
can_rx_offload_get_echo_skb_queue_timestamp() Rename the rx_offload_get_echo_skb() function to can_rx_offload_get_echo_skb_queue_timestamp(), since it inserts the echo skb into the rx-offload queue sorted by timestamp. This is a preparation for adding can_rx_offload_get_echo_skb_queue_tail(), which adds the echo skb to the end of the queue. This is intended for devices that do not support timestamps. Link: https://lore.kernel.org/all/20230718-gs_usb-rx-offload-v2-1-716e542d14d5@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2023-06-22can: length: refactor frame lengths definition to add size in bitsVincent Mailhol
Introduce a method to calculate the exact size in bits of a CAN(-FD) frame with or without dynamic bitstuffing. These are all the possible combinations taken into account: - Classical CAN or CAN-FD - Standard or Extended frame format - CAN-FD CRC17 or CRC21 - Include or not intermission Instead of doing several individual macro definitions, declare the can_frame_bits() function-like macro. To this extent, do a full refactoring of the length definitions. In addition add the can_frame_bytes(). This function-like macro replaces the existing macro: - CAN_FRAME_OVERHEAD_SFF: can_frame_bytes(false, false, 0) - CAN_FRAME_OVERHEAD_EFF: can_frame_bytes(false, true, 0) - CANFD_FRAME_OVERHEAD_SFF: can_frame_bytes(true, false, 0) - CANFD_FRAME_OVERHEAD_EFF: can_frame_bytes(true, true, 0) Function-like macros were chosen over inline functions because they can be used to initialize const struct fields. The different maximum frame lengths (maximum data length, including intermission) are as follow: Frame type bits bytes ------------------------------------------------------- Classic CAN SFF no bitstuffing 111 14 Classic CAN EFF no bitstuffing 131 17 Classic CAN SFF bitstuffing 135 17 Classic CAN EFF bitstuffing 160 20 CAN-FD SFF no bitstuffing 579 73 CAN-FD EFF no bitstuffing 598 75 CAN-FD SFF bitstuffing 712 89 CAN-FD EFF bitstuffing 736 92 The macro CAN_FRAME_LEN_MAX and CANFD_FRAME_LEN_MAX are kept as an alias to, respectively, can_frame_bytes(false, true, CAN_MAX_DLEN) and can_frame_bytes(true, true, CANFD_MAX_DLEN). In addition to the above: - Use ISO 11898-1:2015 definitions for the names of the CAN frame fields. - Include linux/bits.h for use of BITS_PER_BYTE. - Include linux/math.h for use of mult_frac() and DIV_ROUND_UP(). N.B: the use of DIV_ROUND_UP() is not new to this patch, but the include was previously omitted. - Add copyright 2023 for myself. Suggested-by: Thomas Kopp <Thomas.Kopp@microchip.com> Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Reviewed-by: Thomas Kopp <Thomas.Kopp@microchip.com> Link: https://lore.kernel.org/all/20230611025728.450837-4-mailhol.vincent@wanadoo.fr Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2023-06-22can: length: fix description of the RRS fieldVincent Mailhol
The CAN-FD frames only have one reserved bit. The bit corresponding to Classical CAN frame's RTR bit is called the "Remote Request Substitution (RRS)" [1]. N.B. The RRS is not to be confused with the Substitute Remote Request (SRR). Fix the description in the CANFD_FRAME_OVERHEAD_SFF/EFF macros. The total remains unchanged, so this is just a documentation fix. In addition to the above add myself as copyright owner for 2020 (as coauthor of the initial version, c.f. Fixes tag). [1] ISO 11898-1:2015 paragraph 10.4.2.3 "Arbitration field": RSS bit [only in FD Frames] The RRS bit shall be transmitted in FD Frames at the position of the RTR bit in Classical Frames. The RRS bit shall be transmitted dominant, but receivers shall accept recessive and dominant RRS bits. Fixes: 85d99c3e2a13 ("can: length: can_skb_get_frame_len(): introduce function to get data length of frame in data link layer") Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Reviewed-by: Thomas Kopp <Thomas.Kopp@microchip.com> Link: https://lore.kernel.org/all/20230611025728.450837-3-mailhol.vincent@wanadoo.fr Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2023-06-22can: length: fix bitstuffing countVincent Mailhol
The Stuff Bit Count is always coded on 4 bits [1]. Update the Stuff Bit Count size accordingly. In addition, the CRC fields of CAN FD Frames contain stuff bits at fixed positions called fixed stuff bits [2]. The CRC field starts with a fixed stuff bit and then has another fixed stuff bit after each fourth bit [2], which allows us to derive this formula: FSB count = 1 + round_down(len(CRC field)/4) The length of the CRC field is [1]: len(CRC field) = len(Stuff Bit Count) + len(CRC) = 4 + len(CRC) with len(CRC) either 17 or 21 bits depending of the payload length. In conclusion, for CRC17: FSB count = 1 + round_down((4 + 17)/4) = 6 and for CRC 21: FSB count = 1 + round_down((4 + 21)/4) = 7 Add a Fixed Stuff bits (FSB) field with above values and update CANFD_FRAME_OVERHEAD_SFF and CANFD_FRAME_OVERHEAD_EFF accordingly. [1] ISO 11898-1:2015 section 10.4.2.6 "CRC field": The CRC field shall contain the CRC sequence followed by a recessive CRC delimiter. For FD Frames, the CRC field shall also contain the stuff count. Stuff count If FD Frames, the stuff count shall be at the beginning of the CRC field. It shall consist of the stuff bit count modulo 8 in a 3-bit gray code followed by a parity bit [...] [2] ISO 11898-1:2015 paragraph 10.5 "Frame coding": In the CRC field of FD Frames, the stuff bits shall be inserted at fixed positions; they are called fixed stuff bits. There shall be a fixed stuff bit before the first bit of the stuff count, even if the last bits of the preceding field are a sequence of five consecutive bits of identical value, there shall be only the fixed stuff bit, there shall not be two consecutive stuff bits. A further fixed stuff bit shall be inserted after each fourth bit of the CRC field [...] Fixes: 85d99c3e2a13 ("can: length: can_skb_get_frame_len(): introduce function to get data length of frame in data link layer") Suggested-by: Thomas Kopp <Thomas.Kopp@microchip.com> Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Reviewed-by: Thomas Kopp <Thomas.Kopp@microchip.com> Link: https://lore.kernel.org/all/20230611025728.450837-2-mailhol.vincent@wanadoo.fr Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2023-05-15can: length: make header self containedMarc Kleine-Budde
Include the headers that "can/length.h" depends on. Fixes: bdd2e413192d ("can: dev: move length related code into seperate file") Link: https://lore.kernel.org/all/20230509122854.350426-1-mkl@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2023-02-08can: bittiming: can_calc_bittiming(): add missing parameter to no-op functionMarc Kleine-Budde
In commit 286c0e09e8e0 ("can: bittiming: can_changelink() pass extack down callstack") a new parameter was added to can_calc_bittiming(), however the static inline no-op (which is used if CONFIG_CAN_CALC_BITTIMING is disabled) wasn't converted. Add the new parameter to the static inline no-op of can_calc_bittiming(). Fixes: 286c0e09e8e0 ("can: bittiming: can_changelink() pass extack down callstack") Reported-by: kernel test robot <lkp@intel.com> Link: https://lore.kernel.org/20230207201734.2905618-1-mkl@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2023-02-06can: bittiming: factor out can_sjw_set_default() and can_sjw_check()Marc Kleine-Budde
Factor out the functionality of assigning a SJW default value into can_sjw_set_default() and the checking the SJW limits into can_sjw_check(). This functions will be improved and called from a different function in the following patches. Link: https://lore.kernel.org/all/20230202110854.2318594-11-mkl@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2023-02-06can: bittiming: can_changelink() pass extack down callstackMarc Kleine-Budde
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 <mkl@pengutronix.de>
2022-11-24can: sja1000: fix size of OCR_MODE_MASK defineHeiko Schocher
bitfield mode in ocr register has only 2 bits not 3, so correct the OCR_MODE_MASK define. Signed-off-by: Heiko Schocher <hs@denx.de> Link: https://lore.kernel.org/all/20221123071636.2407823-1-hs@denx.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2022-11-07can: dev: fix skb drop checkOliver Hartkopp
In commit a6d190f8c767 ("can: skb: drop tx skb if in listen only mode") the priv->ctrlmode element is read even on virtual CAN interfaces that do not create the struct can_priv at startup. This out-of-bounds read may lead to CAN frame drops for virtual CAN interfaces like vcan and vxcan. This patch mainly reverts the original commit and adds a new helper for CAN interface drivers that provide the required information in struct can_priv. Fixes: a6d190f8c767 ("can: skb: drop tx skb if in listen only mode") Reported-by: Dariusz Stojaczyk <Dariusz.Stojaczyk@opensynergy.com> Cc: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Cc: Max Staudt <max@enpas.org> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Acked-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Link: https://lore.kernel.org/all/20221102095431.36831-1-socketcan@hartkopp.net Cc: stable@vger.kernel.org # 6.0.x [mkl: patch pch_can, too] Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2022-09-15can: dev: add CAN XL support to virtual CANOliver Hartkopp
Make use of new can_skb_get_data_len() helper. Add support for variable CANXL MTU using the new can_is_canxl_dev_mtu(). Acked-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://lore.kernel.org/all/20220912170725.120748-7-socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2022-09-15can: canxl: update CAN infrastructure for CAN XL framesOliver Hartkopp
- add new ETH_P_CANXL ethernet protocol type - update skb checks for CAN XL - add alloc_canxl_skb() which now needs a data length parameter - introduce init_can_skb_reserve() to reduce code duplication Acked-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://lore.kernel.org/all/20220912170725.120748-6-socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2022-09-15can: skb: add skb CAN frame data length helpersOliver Hartkopp
Add two helpers to retrieve the data length from CAN sk_buffs and prepare the length information to be a uint16 value for the CAN XL support. Acked-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://lore.kernel.org/all/20220912170725.120748-3-socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2022-09-15can: skb: unify skb CAN frame identification helpersOliver Hartkopp
Replace open coded checks for sk_buffs containing Classical CAN and CAN FD frame structures as a preparation for CAN XL support. With the added length check the unintended processing of CAN XL frames having the CANXL_XLF bit set can be suppressed even when the skb->len fits to non CAN XL frames. The CAN_RAW socket needs a rework to use these helpers. Therefore the use of these helpers is postponed to the CAN_RAW CAN XL integration. The J1939 protocol gets a check for Classical CAN frames too. Acked-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://lore.kernel.org/all/20220912170725.120748-2-socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2022-07-28can: dev: add generic function can_eth_ioctl_hwts()Vincent Mailhol
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 <mailhol.vincent@wanadoo.fr> Link: https://lore.kernel.org/all/20220727101641.198847-9-mailhol.vincent@wanadoo.fr Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2022-07-28can: dev: add generic function can_ethtool_op_get_ts_info_hwts()Vincent Mailhol
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 <mailhol.vincent@wanadoo.fr> Link: https://lore.kernel.org/all/20220727101641.198847-8-mailhol.vincent@wanadoo.fr Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2022-07-03can: netlink: dump bitrate 0 if can_priv::bittiming.bitrate is -1UDario Binacchi
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 <mkl@pengutronix.de> Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com> Tested-by: Jeroen Hofstee <jhofstee@victronenergy.com> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2022-06-11can: skb: move can_dropped_invalid_skb() and can_skb_headroom_valid() to skb.cVincent Mailhol
The functions can_dropped_invalid_skb() and can_skb_headroom_valid() grew a lot over the years to a point which it does not make much sense to have them defined as static inline in header files. Move those two functions to the .c counterpart of skb.h. can_skb_headroom_valid()'s only caller being can_dropped_invalid_skb(), the declaration is removed from the header. Only can_dropped_invalid_skb() gets its symbol exported. While doing so, do a small cleanup: add brackets around the else block in can_dropped_invalid_skb(). Link: https://lore.kernel.org/all/20220610143009.323579-7-mailhol.vincent@wanadoo.fr Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Reported-by: kernel test robot <lkp@intel.com> Acked-by: Max Staudt <max@enpas.org> Tested-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2022-05-19can: can-dev: remove obsolete CAN LED supportOliver Hartkopp
Since commit 30f3b42147ba6f ("can: mark led trigger as broken") the CAN specific LED support was disabled and marked as BROKEN. As the common LED support with CONFIG_LEDS_TRIGGER_NETDEV should do this work now the code can be removed as preparation for a CAN netdevice Kconfig rework. Link: https://lore.kernel.org/all/20220518154527.29046-1-socketcan@hartkopp.net Suggested-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> [mkl: remove led.h from MAINTAINERS] Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2022-04-19can: rx-offload: rename can_rx_offload_queue_sorted() -> ↵Marc Kleine-Budde
can_rx_offload_queue_timestamp() This patch renames the function can_rx_offload_queue_sorted() to can_rx_offload_queue_timestamp(). This better describes what the function does, it adds a newly RX'ed skb to the sorted queue by its timestamp. Link: https://lore.kernel.org/all/20220417194327.2699059-1-mkl@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2022-02-24can: bittiming: mark function arguments and local variables as constMarc Kleine-Budde
This patch marks the arguments of some functions as well as some local variables as constant. Link: https://lore.kernel.org/all/20220124215642.3474154-7-mkl@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2022-01-05can: dev: reorder struct can_priv members for better packingVincent Mailhol
Save eight bytes of holes on x86-64 architectures by reordering the members of struct can_priv. Before: | $ pahole -C can_priv drivers/net/can/dev/dev.o | struct can_priv { | struct net_device * dev; /* 0 8 */ | struct can_device_stats can_stats; /* 8 24 */ | const struct can_bittiming_const * bittiming_const; /* 32 8 */ | const struct can_bittiming_const * data_bittiming_const; /* 40 8 */ | struct can_bittiming bittiming; /* 48 32 */ | /* --- cacheline 1 boundary (64 bytes) was 16 bytes ago --- */ | struct can_bittiming data_bittiming; /* 80 32 */ | const struct can_tdc_const * tdc_const; /* 112 8 */ | struct can_tdc tdc; /* 120 12 */ | /* --- cacheline 2 boundary (128 bytes) was 4 bytes ago --- */ | unsigned int bitrate_const_cnt; /* 132 4 */ | const u32 * bitrate_const; /* 136 8 */ | const u32 * data_bitrate_const; /* 144 8 */ | unsigned int data_bitrate_const_cnt; /* 152 4 */ | u32 bitrate_max; /* 156 4 */ | struct can_clock clock; /* 160 4 */ | unsigned int termination_const_cnt; /* 164 4 */ | const u16 * termination_const; /* 168 8 */ | u16 termination; /* 176 2 */ | | /* XXX 6 bytes hole, try to pack */ | | struct gpio_desc * termination_gpio; /* 184 8 */ | /* --- cacheline 3 boundary (192 bytes) --- */ | u16 termination_gpio_ohms[2]; /* 192 4 */ | enum can_state state; /* 196 4 */ | u32 ctrlmode; /* 200 4 */ | u32 ctrlmode_supported; /* 204 4 */ | int restart_ms; /* 208 4 */ | | /* XXX 4 bytes hole, try to pack */ | | struct delayed_work restart_work; /* 216 88 */ | | /* XXX last struct has 4 bytes of padding */ | | /* --- cacheline 4 boundary (256 bytes) was 48 bytes ago --- */ | int (*do_set_bittiming)(struct net_device *); /* 304 8 */ | int (*do_set_data_bittiming)(struct net_device *); /* 312 8 */ | /* --- cacheline 5 boundary (320 bytes) --- */ | int (*do_set_mode)(struct net_device *, enum can_mode); /* 320 8 */ | int (*do_set_termination)(struct net_device *, u16); /* 328 8 */ | int (*do_get_state)(const struct net_device *, enum can_state *); /* 336 8 */ | int (*do_get_berr_counter)(const struct net_device *, struct can_berr_counter *); /* 344 8 */ | unsigned int echo_skb_max; /* 352 4 */ | | /* XXX 4 bytes hole, try to pack */ | | struct sk_buff * * echo_skb; /* 360 8 */ | | /* size: 368, cachelines: 6, members: 32 */ | /* sum members: 354, holes: 3, sum holes: 14 */ | /* paddings: 1, sum paddings: 4 */ | /* last cacheline: 48 bytes */ | }; After: | $ pahole -C can_priv drivers/net/can/dev/dev.o | struct can_priv { | struct net_device * dev; /* 0 8 */ | struct can_device_stats can_stats; /* 8 24 */ | const struct can_bittiming_const * bittiming_const; /* 32 8 */ | const struct can_bittiming_const * data_bittiming_const; /* 40 8 */ | struct can_bittiming bittiming; /* 48 32 */ | /* --- cacheline 1 boundary (64 bytes) was 16 bytes ago --- */ | struct can_bittiming data_bittiming; /* 80 32 */ | const struct can_tdc_const * tdc_const; /* 112 8 */ | struct can_tdc tdc; /* 120 12 */ | /* --- cacheline 2 boundary (128 bytes) was 4 bytes ago --- */ | unsigned int bitrate_const_cnt; /* 132 4 */ | const u32 * bitrate_const; /* 136 8 */ | const u32 * data_bitrate_const; /* 144 8 */ | unsigned int data_bitrate_const_cnt; /* 152 4 */ | u32 bitrate_max; /* 156 4 */ | struct can_clock clock; /* 160 4 */ | unsigned int termination_const_cnt; /* 164 4 */ | const u16 * termination_const; /* 168 8 */ | u16 termination; /* 176 2 */ | | /* XXX 6 bytes hole, try to pack */ | | struct gpio_desc * termination_gpio; /* 184 8 */ | /* --- cacheline 3 boundary (192 bytes) --- */ | u16 termination_gpio_ohms[2]; /* 192 4 */ | unsigned int echo_skb_max; /* 196 4 */ | struct sk_buff * * echo_skb; /* 200 8 */ | enum can_state state; /* 208 4 */ | u32 ctrlmode; /* 212 4 */ | u32 ctrlmode_supported; /* 216 4 */ | int restart_ms; /* 220 4 */ | struct delayed_work restart_work; /* 224 88 */ | | /* XXX last struct has 4 bytes of padding */ | | /* --- cacheline 4 boundary (256 bytes) was 56 bytes ago --- */ | int (*do_set_bittiming)(struct net_device *); /* 312 8 */ | /* --- cacheline 5 boundary (320 bytes) --- */ | int (*do_set_data_bittiming)(struct net_device *); /* 320 8 */ | int (*do_set_mode)(struct net_device *, enum can_mode); /* 328 8 */ | int (*do_set_termination)(struct net_device *, u16); /* 336 8 */ | int (*do_get_state)(const struct net_device *, enum can_state *); /* 344 8 */ | int (*do_get_berr_counter)(const struct net_device *, struct can_berr_counter *); /* 352 8 */ | | /* size: 360, cachelines: 6, members: 32 */ | /* sum members: 354, holes: 1, sum holes: 6 */ | /* paddings: 1, sum paddings: 4 */ | /* last cacheline: 40 bytes */ | }; Link: https://lore.kernel.org/all/20211213160226.56219-4-mailhol.vincent@wanadoo.fr Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2022-01-05can: dev: add sanity check in can_set_static_ctrlmode()Vincent Mailhol
Previous patch removed can_priv::ctrlmode_static to replace it with can_get_static_ctrlmode(). A condition sine qua non for this to work is that the controller static modes should never be set in can_priv::ctrlmode_supported (c.f. the comment on can_priv::ctrlmode_supported which states that it is for "options that can be *modified* by netlink"). Also, this condition is already correctly fulfilled by all existing drivers which rely on the ctrlmode_static feature. Nonetheless, we added an extra safeguard in can_set_static_ctrlmode() to return an error value and to warn the developer who would be adventurous enough to set to static a given feature that is already set to supported. The drivers which rely on the static controller mode are then updated to check the return value of can_set_static_ctrlmode(). Link: https://lore.kernel.org/all/20211213160226.56219-3-mailhol.vincent@wanadoo.fr Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2022-01-05can: dev: replace can_priv::ctrlmode_static by can_get_static_ctrlmode()Vincent Mailhol
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 <mailhol.vincent@wanadoo.fr> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2022-01-05can: do not increase tx_bytes statistics for RTR framesVincent Mailhol
The actual payload length of the CAN Remote Transmission Request (RTR) frames is always 0, i.e. no payload is transmitted on the wire. However, those RTR frames still use the DLC to indicate the length of the requested frame. As such, net_device_stats::tx_bytes should not be increased when sending RTR frames. The function can_get_echo_skb() already returns the correct length, even for RTR frames (c.f. [1]). However, for historical reasons, the drivers do not use can_get_echo_skb()'s return value and instead, most of them store a temporary length (or dlc) in some local structure or array. Using the return value of can_get_echo_skb() solves the issue. After doing this, such length/dlc fields become unused and so this patch does the adequate cleaning when needed. This patch fixes all the CAN drivers. Finally, can_get_echo_skb() is decorated with the __must_check attribute in order to force future drivers to correctly use its return value (else the compiler would emit a warning). [1] commit ed3320cec279 ("can: dev: __can_get_echo_skb(): fix real payload length return value for RTR frames") Link: https://lore.kernel.org/all/20211207121531.42941-6-mailhol.vincent@wanadoo.fr Cc: Nicolas Ferre <nicolas.ferre@microchip.com> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> Cc: Ludovic Desroches <ludovic.desroches@microchip.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: Chen-Yu Tsai <wens@csie.org> Cc: Jernej Skrabec <jernej.skrabec@gmail.com> Cc: Yasushi SHOJI <yashi@spacecubics.com> Cc: Oliver Hartkopp <socketcan@hartkopp.net> Cc: Stephane Grosjean <s.grosjean@peak-system.com> Cc: Andreas Larsson <andreas@gaisler.com> Tested-by: Jimmy Assarsson <extja@kvaser.com> # kvaser Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Acked-by: Stefan Mätje <stefan.maetje@esd.eu> # esd_usb2 Tested-by: Stefan Mätje <stefan.maetje@esd.eu> # esd_usb2 [mkl: add conversion for grcan] Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
generated by cgit (git 2.34.1) at 2025-12-15 14:11:10 +0000