kernel/linux.git/include/linux/can/bittiming.h, branch v6.12.80

can: bittiming: can_calc_bittiming(): add missing parameter to no-op function

2023-02-08T20:53:24+00:00

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 Link: https://lore.kernel.org/20230207201734.2905618-1-mkl@pengutronix.de Signed-off-by: Marc Kleine-Budde

can: bittiming: factor out can_sjw_set_default() and can_sjw_check()

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

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

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: 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: bittiming: mark function arguments and local variables as const

2022-02-24T07:26:03+00:00

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

can: bittiming: replace CAN units with the generic ones from linux/units.h

2021-12-08T09:12:58+00:00

In [1], we introduced a set of units in linux/can/bittiming.h. Since then, generic SI prefixes were added to linux/units.h in [2]. Those new prefixes can perfectly replace CAN specific ones. This patch replaces all occurrences of the CAN units with their corresponding prefix (from linux/units) and the unit (as a comment) according to below table. CAN units SI metric prefix (from linux/units) + unit (as a comment) ------------------------------------------------------------------------ CAN_KBPS KILO /* BPS */ CAN_MBPS MEGA /* BPS */ CAM_MHZ MEGA /* Hz */ The definition are then removed from linux/can/bittiming.h [1] commit 1d7750760b70 ("can: bittiming: add CAN_KBPS, CAN_MBPS and CAN_MHZ macros") [2] commit 26471d4a6cf8 ("units: Add SI metric prefix definitions") Link: https://lore.kernel.org/all/20211124014536.782550-1-mailhol.vincent@wanadoo.fr Suggested-by: Jimmy Assarsson Suggested-by: Oliver Hartkopp Signed-off-by: Vincent Mailhol Signed-off-by: Marc Kleine-Budde

can: bittiming: change can_calc_tdco()'s prototype to not directly modify priv

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

The function can_calc_tdco() directly retrieves can_priv from the net_device and directly modifies it. This is annoying for the upcoming patch. In drivers/net/can/dev/netlink.c:can_changelink(), the data bittiming are written to a temporary structure and memcpyed to can_priv only after everything succeeded. In the next patch, where we will introduce the netlink interface for TDC parameters, we will add a new TDC block which can potentially fail. For this reason, the data bittiming temporary structure has to be copied after that to-be-introduced TDC block. However, TDC also needs to access data bittiming information. We change the prototype so that the data bittiming structure is passed to can_calc_tdco() as an argument instead of retrieving it from priv. This way can_calc_tdco() can access the data bittiming before it gets memcpyed to priv. Link: https://lore.kernel.org/all/20210918095637.20108-4-mailhol.vincent@wanadoo.fr Signed-off-by: Vincent Mailhol Signed-off-by: Marc Kleine-Budde

can: bittiming: change unit of TDC parameters to clock periods

2021-10-24T14:24:28+00:00

In the current implementation, all Transmission Delay Compensation (TDC) parameters are expressed in time quantum. However, ISO 11898-1 actually specifies that these should be expressed in *minimum* time quantum. Furthermore, the minimum time quantum is specified to be "one node clock period long" (c.f. paragraph 11.3.1.1 "Bit time"). For sake of simplicity, we prefer to use the "clock period" term instead of "minimum time quantum" because we believe that it is more broadly understood. This patch fixes that discrepancy by updating the documentation and the formula for TDCO calculation. N.B. In can_calc_tdco(), the sample point (in time quantum) was calculated using a division, thus introducing a risk of rounding and truncation errors. On top of changing the unit to clock period, we also modified the formula to use only additions. Link: https://lore.kernel.org/all/20210918095637.20108-3-mailhol.vincent@wanadoo.fr Suggested-by: Stefan Mätje Signed-off-by: Vincent Mailhol Signed-off-by: Marc Kleine-Budde

can: bittiming: allow TDC{V,O} to be zero and add can_tdc_const::tdc{v,o,f}_min

2021-10-24T14:24:28+00:00

ISO 11898-1 specifies in section 11.3.3 "Transmitter delay compensation" that "the configuration range for [the] SSP position shall be at least 0 to 63 minimum time quanta." Because SSP = TDCV + TDCO, it means that we should allow both TDCV and TDCO to hold zero value in order to honor SSP's minimum possible value. However, current implementation assigned special meaning to TDCV and TDCO's zero values: * TDCV = 0 -> TDCV is automatically measured by the transceiver. * TDCO = 0 -> TDC is off. In order to allow for those values to really be zero and to maintain current features, we introduce two new flags: * CAN_CTRLMODE_TDC_AUTO indicates that the controller support automatic measurement of TDCV. * CAN_CTRLMODE_TDC_MANUAL indicates that the controller support manual configuration of TDCV. N.B.: current implementation failed to provide an option for the driver to indicate that only manual mode was supported. TDC is disabled if both CAN_CTRLMODE_TDC_AUTO and CAN_CTRLMODE_TDC_MANUAL flags are off, c.f. the helper function can_tdc_is_enabled() which is also introduced in this patch. Also, this patch adds three fields: tdcv_min, tdco_min and tdcf_min to struct can_tdc_const. While we are not convinced that those three fields could be anything else than zero, we can imagine that some controllers might specify a lower bound on these. Thus, those minimums are really added "just in case". Comments of struct can_tdc and can_tdc_const are updated accordingly. Finally, the changes are applied to the etas_es58x driver. Link: https://lore.kernel.org/all/20210918095637.20108-2-mailhol.vincent@wanadoo.fr Signed-off-by: Vincent Mailhol Signed-off-by: Marc Kleine-Budde

can: bittiming: fix documentation for struct can_tdc

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

This patch fixes a typo in the documentation for struct can_tdc::tdcv. The number "0" refers to automatic mode not the letter "O". Further two grammar errors in the documentation for struct can_tdc are fixed. First grammar error: add a missing third person 's'. Second grammar error: replace "such as" by "such that". The intent is to give a condition, not an example. Fixes: 289ea9e4ae59 ("can: add new CAN FD bittiming parameters: Transmitter Delay Compensation (TDC)") Link: https://lore.kernel.org/r/20210616095922.2430415-1-mkl@pengutronix.de Link: https://lore.kernel.org/r/20210616124057.60723-1-mailhol.vincent@wanadoo.fr Co-developed-by: Vincent Mailhol Signed-off-by: Vincent Mailhol Acked-by: Vincent Mailhol Signed-off-by: Marc Kleine-Budde