From patchwork Sat Sep 18 09:56:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincent Mailhol X-Patchwork-Id: 12503769 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 02980C433EF for ; Sat, 18 Sep 2021 09:57:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DE9F160FBF for ; Sat, 18 Sep 2021 09:57:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244086AbhIRJ6k (ORCPT ); Sat, 18 Sep 2021 05:58:40 -0400 Received: from smtp05.smtpout.orange.fr ([80.12.242.127]:50662 "EHLO smtp.smtpout.orange.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244179AbhIRJ6g (ORCPT ); Sat, 18 Sep 2021 05:58:36 -0400 Received: from tomoyo.flets-east.jp ([114.149.34.46]) by smtp.orange.fr with ESMTPA id RX5Zmuh4X1yYBRX5qm0kE0; Sat, 18 Sep 2021 11:57:12 +0200 X-ME-Helo: tomoyo.flets-east.jp X-ME-Auth: MDU0YmViZGZmMDIzYiBlMiM2NTczNTRjNWZkZTMwOGRiOGQ4ODf3NWI1ZTMyMzdiODlhOQ== X-ME-Date: Sat, 18 Sep 2021 11:57:12 +0200 X-ME-IP: 114.149.34.46 From: Vincent Mailhol To: Marc Kleine-Budde , linux-can@vger.kernel.org Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, =?utf-8?q?Stefan_M?= =?utf-8?q?=C3=A4tje?= , Vincent Mailhol Subject: [PATCH v6 1/6] can: bittiming: allow TDC{V,O} to be zero and add can_tdc_const::tdc{v,o,f}_min Date: Sat, 18 Sep 2021 18:56:32 +0900 Message-Id: <20210918095637.20108-2-mailhol.vincent@wanadoo.fr> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210918095637.20108-1-mailhol.vincent@wanadoo.fr> References: <20210918095637.20108-1-mailhol.vincent@wanadoo.fr> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org 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. Signed-off-by: Vincent Mailhol --- drivers/net/can/dev/bittiming.c | 10 ++-- drivers/net/can/usb/etas_es58x/es58x_fd.c | 7 ++- include/linux/can/bittiming.h | 64 +++++++++++++++++------ include/linux/can/dev.h | 4 ++ include/uapi/linux/can/netlink.h | 2 + 5 files changed, 65 insertions(+), 22 deletions(-) diff --git a/drivers/net/can/dev/bittiming.c b/drivers/net/can/dev/bittiming.c index f49170eadd54..7dbda411915a 100644 --- a/drivers/net/can/dev/bittiming.c +++ b/drivers/net/can/dev/bittiming.c @@ -182,9 +182,12 @@ void can_calc_tdco(struct net_device *dev) struct can_tdc *tdc = &priv->tdc; const struct can_tdc_const *tdc_const = priv->tdc_const; - if (!tdc_const) + if (!tdc_const || + !(priv->ctrlmode_supported & CAN_CTRLMODE_TDC_AUTO)) return; + priv->ctrlmode &= ~CAN_CTRLMODE_TDC_MASK; + /* As specified in ISO 11898-1 section 11.3.3 "Transmitter * delay compensation" (TDC) is only applicable if data BRP is * one or two. @@ -193,9 +196,10 @@ void can_calc_tdco(struct net_device *dev) /* Reuse "normal" sample point and convert it to time quanta */ u32 sample_point_in_tq = can_bit_time(dbt) * dbt->sample_point / 1000; + if (sample_point_in_tq < tdc_const->tdco_min) + return; tdc->tdco = min(sample_point_in_tq, tdc_const->tdco_max); - } else { - tdc->tdco = 0; + priv->ctrlmode |= CAN_CTRLMODE_TDC_AUTO; } } #endif /* CONFIG_CAN_CALC_BITTIMING */ diff --git a/drivers/net/can/usb/etas_es58x/es58x_fd.c b/drivers/net/can/usb/etas_es58x/es58x_fd.c index af042aa55f59..4f0cae29f4d8 100644 --- a/drivers/net/can/usb/etas_es58x/es58x_fd.c +++ b/drivers/net/can/usb/etas_es58x/es58x_fd.c @@ -428,7 +428,7 @@ static int es58x_fd_enable_channel(struct es58x_priv *priv) es58x_fd_convert_bittiming(&tx_conf_msg.data_bittiming, &priv->can.data_bittiming); - if (priv->can.tdc.tdco) { + if (can_tdc_is_enabled(&priv->can)) { tx_conf_msg.tdc_enabled = 1; tx_conf_msg.tdco = cpu_to_le16(priv->can.tdc.tdco); tx_conf_msg.tdcf = cpu_to_le16(priv->can.tdc.tdcf); @@ -505,8 +505,11 @@ static const struct can_bittiming_const es58x_fd_data_bittiming_const = { * Register" from Microchip. */ static const struct can_tdc_const es58x_tdc_const = { + .tdcv_min = 0, .tdcv_max = 0, /* Manual mode not supported. */ + .tdco_min = 0, .tdco_max = 127, + .tdcf_min = 0, .tdcf_max = 127 }; @@ -523,7 +526,7 @@ const struct es58x_parameters es58x_fd_param = { .clock = {.freq = 80 * CAN_MHZ}, .ctrlmode_supported = CAN_CTRLMODE_LOOPBACK | CAN_CTRLMODE_LISTENONLY | CAN_CTRLMODE_3_SAMPLES | CAN_CTRLMODE_FD | CAN_CTRLMODE_FD_NON_ISO | - CAN_CTRLMODE_CC_LEN8_DLC, + CAN_CTRLMODE_CC_LEN8_DLC | CAN_CTRLMODE_TDC_AUTO, .tx_start_of_frame = 0xCEFA, /* FACE in little endian */ .rx_start_of_frame = 0xFECA, /* CAFE in little endian */ .tx_urb_cmd_max_len = ES58X_FD_TX_URB_CMD_MAX_LEN, diff --git a/include/linux/can/bittiming.h b/include/linux/can/bittiming.h index 9de6e9053e34..9e20260611cc 100644 --- a/include/linux/can/bittiming.h +++ b/include/linux/can/bittiming.h @@ -19,6 +19,9 @@ /* Megahertz */ #define CAN_MHZ 1000000UL +#define CAN_CTRLMODE_TDC_MASK \ + (CAN_CTRLMODE_TDC_AUTO | CAN_CTRLMODE_TDC_MANUAL) + /* * struct can_tdc - CAN FD Transmission Delay Compensation parameters * @@ -33,29 +36,43 @@ * * This structure contains the parameters to calculate that SSP. * - * @tdcv: Transmitter Delay Compensation Value. Distance, in time - * quanta, from when the bit is sent on the TX pin to when it is - * received on the RX pin of the transmitter. Possible options: + * -+----------- one bit ----------+-- TX pin + * |<--- Sample Point --->| + * + * --+----------- one bit ----------+-- RX pin + * |<-------- TDCV -------->| + * |<------- TDCO ------->| + * |<----------- Secondary Sample Point ---------->| + * + * @tdcv: Transmitter Delay Compensation Value. The time needed for + * the signal to propagate, i.e. the distance, in time quanta, + * from the start of the bit on the TX pin to when it is received + * on the RX pin. @tdcv depends on the controller modes: + * + * CAN_CTRLMODE_TDC_AUTO is set: The transceiver dynamically + * measures @tdcv for each transmitted CAN FD frame and the + * value provided here should be ignored. * - * 0: automatic mode. The controller dynamically measures @tdcv - * for each transmitted CAN FD frame. + * CAN_CTRLMODE_TDC_MANUAL is set: use the fixed provided @tdcv + * value. * - * Other values: manual mode. Use the fixed provided value. + * N.B. CAN_CTRLMODE_TDC_AUTO and CAN_CTRLMODE_TDC_MANUAL are + * mutually exclusive. Only one can be set at a time. If both + * CAN_TDC_CTRLMODE_AUTO and CAN_TDC_CTRLMODE_MANUAL are unset, + * TDC is disabled and all the values of this structure should be + * ignored. * * @tdco: Transmitter Delay Compensation Offset. Offset value, in time * quanta, defining the distance between the start of the bit * reception on the RX pin of the transceiver and the SSP * position such that SSP = @tdcv + @tdco. * - * If @tdco is zero, then TDC is disabled and both @tdcv and - * @tdcf should be ignored. - * * @tdcf: Transmitter Delay Compensation Filter window. Defines the - * minimum value for the SSP position in time quanta. If SSP is - * less than @tdcf, then no delay compensations occur and the - * normal sampling point is used instead. The feature is enabled - * if and only if @tdcv is set to zero (automatic mode) and @tdcf - * is configured to a value greater than @tdco. + * minimum value for the SSP position in time quanta. If the SSP + * position is less than @tdcf, then no delay compensations occur + * and the normal sampling point is used instead. The feature is + * enabled if and only if @tdcv is set to zero (automatic mode) + * and @tdcf is configured to a value greater than @tdco. */ struct can_tdc { u32 tdcv; @@ -67,19 +84,32 @@ struct can_tdc { * struct can_tdc_const - CAN hardware-dependent constant for * Transmission Delay Compensation * - * @tdcv_max: Transmitter Delay Compensation Value maximum value. - * Should be set to zero if the controller does not support - * manual mode for tdcv. + * @tdcv_min: Transmitter Delay Compensation Value minimum value. If + * the controller does not support manual mode for tdcv + * (c.f. flag CAN_CTRLMODE_TDC_MANUAL) then this value is + * ignored. + * @tdcv_max: Transmitter Delay Compensation Value maximum value. If + * the controller does not support manual mode for tdcv + * (c.f. flag CAN_CTRLMODE_TDC_MANUAL) then this value is + * ignored. + * + * @tdco_min: Transmitter Delay Compensation Offset minimum value. * @tdco_max: Transmitter Delay Compensation Offset maximum value. * Should not be zero. If the controller does not support TDC, * then the pointer to this structure should be NULL. + * + * @tdcf_min: Transmitter Delay Compensation Filter window minimum + * value. If @tdcf_max is zero, this value is ignored. * @tdcf_max: Transmitter Delay Compensation Filter window maximum * value. Should be set to zero if the controller does not * support this feature. */ struct can_tdc_const { + u32 tdcv_min; u32 tdcv_max; + u32 tdco_min; u32 tdco_max; + u32 tdcf_min; u32 tdcf_max; }; diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h index 2413253e54c7..6dacbbb41e68 100644 --- a/include/linux/can/dev.h +++ b/include/linux/can/dev.h @@ -96,6 +96,10 @@ struct can_priv { #endif }; +static inline bool can_tdc_is_enabled(const struct can_priv *priv) +{ + return !!(priv->ctrlmode & CAN_CTRLMODE_TDC_MASK); +} /* helper to define static CAN controller features at device creation time */ static inline void can_set_static_ctrlmode(struct net_device *dev, diff --git a/include/uapi/linux/can/netlink.h b/include/uapi/linux/can/netlink.h index f730d443b918..004cd09a7d49 100644 --- a/include/uapi/linux/can/netlink.h +++ b/include/uapi/linux/can/netlink.h @@ -101,6 +101,8 @@ struct can_ctrlmode { #define CAN_CTRLMODE_PRESUME_ACK 0x40 /* Ignore missing CAN ACKs */ #define CAN_CTRLMODE_FD_NON_ISO 0x80 /* CAN FD in non-ISO mode */ #define CAN_CTRLMODE_CC_LEN8_DLC 0x100 /* Classic CAN DLC option */ +#define CAN_CTRLMODE_TDC_AUTO 0x200 /* CAN transiver automatically calculates TDCV */ +#define CAN_CTRLMODE_TDC_MANUAL 0x400 /* TDCV is manually set up by user */ /* * CAN device statistics From patchwork Sat Sep 18 09:56:33 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Vincent Mailhol X-Patchwork-Id: 12503771 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9C53C433EF for ; Sat, 18 Sep 2021 09:57:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A5A0460FBF for ; Sat, 18 Sep 2021 09:57:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244260AbhIRJ67 (ORCPT ); Sat, 18 Sep 2021 05:58:59 -0400 Received: from smtp05.smtpout.orange.fr ([80.12.242.127]:50534 "EHLO smtp.smtpout.orange.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244179AbhIRJ66 (ORCPT ); Sat, 18 Sep 2021 05:58:58 -0400 Received: from tomoyo.flets-east.jp ([114.149.34.46]) by smtp.orange.fr with ESMTPA id RX5Zmuh4X1yYBRX64m0kFH; Sat, 18 Sep 2021 11:57:34 +0200 X-ME-Helo: tomoyo.flets-east.jp X-ME-Auth: MDU0YmViZGZmMDIzYiBlMiM2NTczNTRjNWZkZTMwOGRiOGQ4ODf3NWI1ZTMyMzdiODlhOQ== X-ME-Date: Sat, 18 Sep 2021 11:57:34 +0200 X-ME-IP: 114.149.34.46 From: Vincent Mailhol To: Marc Kleine-Budde , linux-can@vger.kernel.org Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, =?utf-8?q?Stefan_M?= =?utf-8?q?=C3=A4tje?= , Vincent Mailhol Subject: [PATCH v6 2/6] can: bittiming: change unit of TDC parameters to clock periods Date: Sat, 18 Sep 2021 18:56:33 +0900 Message-Id: <20210918095637.20108-3-mailhol.vincent@wanadoo.fr> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210918095637.20108-1-mailhol.vincent@wanadoo.fr> References: <20210918095637.20108-1-mailhol.vincent@wanadoo.fr> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org 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. Suggested-by: Stefan Mätje Signed-off-by: Vincent Mailhol --- drivers/net/can/dev/bittiming.c | 9 +++++---- include/linux/can/bittiming.h | 28 +++++++++++++++++----------- 2 files changed, 22 insertions(+), 15 deletions(-) diff --git a/drivers/net/can/dev/bittiming.c b/drivers/net/can/dev/bittiming.c index 7dbda411915a..582463bc15f7 100644 --- a/drivers/net/can/dev/bittiming.c +++ b/drivers/net/can/dev/bittiming.c @@ -193,12 +193,13 @@ void can_calc_tdco(struct net_device *dev) * one or two. */ if (dbt->brp == 1 || dbt->brp == 2) { - /* Reuse "normal" sample point and convert it to time quanta */ - u32 sample_point_in_tq = can_bit_time(dbt) * dbt->sample_point / 1000; + /* Sample point in clock periods */ + u32 sample_point_in_tc = (CAN_SYNC_SEG + dbt->prop_seg + + dbt->phase_seg1) * dbt->brp; - if (sample_point_in_tq < tdc_const->tdco_min) + if (sample_point_in_tc < tdc_const->tdco_min) return; - tdc->tdco = min(sample_point_in_tq, tdc_const->tdco_max); + tdc->tdco = min(sample_point_in_tc, tdc_const->tdco_max); priv->ctrlmode |= CAN_CTRLMODE_TDC_AUTO; } } diff --git a/include/linux/can/bittiming.h b/include/linux/can/bittiming.h index 9e20260611cc..aebbe65dab7e 100644 --- a/include/linux/can/bittiming.h +++ b/include/linux/can/bittiming.h @@ -31,8 +31,8 @@ * * To solve this issue, ISO 11898-1 introduces in section 11.3.3 * "Transmitter delay compensation" a SSP (Secondary Sample Point) - * equal to the distance, in time quanta, from the start of the bit - * time on the TX pin to the actual measurement on the RX pin. + * equal to the distance from the start of the bit time on the TX pin + * to the actual measurement on the RX pin. * * This structure contains the parameters to calculate that SSP. * @@ -44,8 +44,13 @@ * |<------- TDCO ------->| * |<----------- Secondary Sample Point ---------->| * + * To increase precision, contrary to the other bittiming parameters + * which are measured in time quanta, the TDC parameters are measured + * in clock periods (also referred as "minimum time quantum" in ISO + * 11898-1). + * * @tdcv: Transmitter Delay Compensation Value. The time needed for - * the signal to propagate, i.e. the distance, in time quanta, + * the signal to propagate, i.e. the distance, in clock periods, * from the start of the bit on the TX pin to when it is received * on the RX pin. @tdcv depends on the controller modes: * @@ -62,17 +67,18 @@ * TDC is disabled and all the values of this structure should be * ignored. * - * @tdco: Transmitter Delay Compensation Offset. Offset value, in time - * quanta, defining the distance between the start of the bit - * reception on the RX pin of the transceiver and the SSP + * @tdco: Transmitter Delay Compensation Offset. Offset value, in + * clock periods, defining the distance between the start of the + * bit reception on the RX pin of the transceiver and the SSP * position such that SSP = @tdcv + @tdco. * * @tdcf: Transmitter Delay Compensation Filter window. Defines the - * minimum value for the SSP position in time quanta. If the SSP - * position is less than @tdcf, then no delay compensations occur - * and the normal sampling point is used instead. The feature is - * enabled if and only if @tdcv is set to zero (automatic mode) - * and @tdcf is configured to a value greater than @tdco. + * minimum value for the SSP position in clock periods. If the + * SSP position is less than @tdcf, then no delay compensations + * occur and the normal sampling point is used instead. The + * feature is enabled if and only if @tdcv is set to zero + * (automatic mode) and @tdcf is configured to a value greater + * than @tdco. */ struct can_tdc { u32 tdcv; From patchwork Sat Sep 18 09:56:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincent Mailhol X-Patchwork-Id: 12503773 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 97306C433EF for ; Sat, 18 Sep 2021 09:57:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 80B6260F6E for ; Sat, 18 Sep 2021 09:57:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244760AbhIRJ7Q (ORCPT ); Sat, 18 Sep 2021 05:59:16 -0400 Received: from smtp05.smtpout.orange.fr ([80.12.242.127]:50048 "EHLO smtp.smtpout.orange.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244345AbhIRJ7C (ORCPT ); Sat, 18 Sep 2021 05:59:02 -0400 Received: from tomoyo.flets-east.jp ([114.149.34.46]) by smtp.orange.fr with ESMTPA id RX5Zmuh4X1yYBRX6Gm0kHR; Sat, 18 Sep 2021 11:57:38 +0200 X-ME-Helo: tomoyo.flets-east.jp X-ME-Auth: MDU0YmViZGZmMDIzYiBlMiM2NTczNTRjNWZkZTMwOGRiOGQ4ODf3NWI1ZTMyMzdiODlhOQ== X-ME-Date: Sat, 18 Sep 2021 11:57:38 +0200 X-ME-IP: 114.149.34.46 From: Vincent Mailhol To: Marc Kleine-Budde , linux-can@vger.kernel.org Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, =?utf-8?q?Stefan_M?= =?utf-8?q?=C3=A4tje?= , Vincent Mailhol Subject: [PATCH v6 3/6] can: bittiming: change can_calc_tdco()'s prototype to not directly modify priv Date: Sat, 18 Sep 2021 18:56:34 +0900 Message-Id: <20210918095637.20108-4-mailhol.vincent@wanadoo.fr> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210918095637.20108-1-mailhol.vincent@wanadoo.fr> References: <20210918095637.20108-1-mailhol.vincent@wanadoo.fr> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org 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. Signed-off-by: Vincent Mailhol --- drivers/net/can/dev/bittiming.c | 17 +++++++---------- drivers/net/can/dev/netlink.c | 3 ++- include/linux/can/bittiming.h | 9 +++++++-- 3 files changed, 16 insertions(+), 13 deletions(-) diff --git a/drivers/net/can/dev/bittiming.c b/drivers/net/can/dev/bittiming.c index 582463bc15f7..d439ea676e6e 100644 --- a/drivers/net/can/dev/bittiming.c +++ b/drivers/net/can/dev/bittiming.c @@ -175,18 +175,15 @@ int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt, return 0; } -void can_calc_tdco(struct net_device *dev) -{ - struct can_priv *priv = netdev_priv(dev); - const struct can_bittiming *dbt = &priv->data_bittiming; - struct can_tdc *tdc = &priv->tdc; - const struct can_tdc_const *tdc_const = priv->tdc_const; +void can_calc_tdco(struct can_tdc *tdc, const struct can_tdc_const *tdc_const, + const struct can_bittiming *dbt, + u32 *ctrlmode, u32 ctrlmode_supported) - if (!tdc_const || - !(priv->ctrlmode_supported & CAN_CTRLMODE_TDC_AUTO)) +{ + if (!tdc_const || !(ctrlmode_supported & CAN_CTRLMODE_TDC_AUTO)) return; - priv->ctrlmode &= ~CAN_CTRLMODE_TDC_MASK; + *ctrlmode &= ~CAN_CTRLMODE_TDC_MASK; /* As specified in ISO 11898-1 section 11.3.3 "Transmitter * delay compensation" (TDC) is only applicable if data BRP is @@ -200,7 +197,7 @@ void can_calc_tdco(struct net_device *dev) if (sample_point_in_tc < tdc_const->tdco_min) return; tdc->tdco = min(sample_point_in_tc, tdc_const->tdco_max); - priv->ctrlmode |= CAN_CTRLMODE_TDC_AUTO; + *ctrlmode |= CAN_CTRLMODE_TDC_AUTO; } } #endif /* CONFIG_CAN_CALC_BITTIMING */ diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c index 80425636049d..e79c9a2ffbfc 100644 --- a/drivers/net/can/dev/netlink.c +++ b/drivers/net/can/dev/netlink.c @@ -189,7 +189,8 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[], memcpy(&priv->data_bittiming, &dbt, sizeof(dbt)); - can_calc_tdco(dev); + can_calc_tdco(&priv->tdc, priv->tdc_const, &priv->data_bittiming, + &priv->ctrlmode, priv->ctrlmode_supported); if (priv->do_set_data_bittiming) { /* Finally, set the bit-timing registers */ diff --git a/include/linux/can/bittiming.h b/include/linux/can/bittiming.h index aebbe65dab7e..20b50baf3a02 100644 --- a/include/linux/can/bittiming.h +++ b/include/linux/can/bittiming.h @@ -123,7 +123,9 @@ struct can_tdc_const { int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt, const struct can_bittiming_const *btc); -void can_calc_tdco(struct net_device *dev); +void can_calc_tdco(struct can_tdc *tdc, const struct can_tdc_const *tdc_const, + const struct can_bittiming *dbt, + u32 *ctrlmode, u32 ctrlmode_supported); #else /* !CONFIG_CAN_CALC_BITTIMING */ static inline int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt, @@ -133,7 +135,10 @@ can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt, return -EINVAL; } -static inline void can_calc_tdco(struct net_device *dev) +static inline void +can_calc_tdco(struct can_tdc *tdc, const struct can_tdc_const *tdc_const, + const struct can_bittiming *dbt, + u32 *ctrlmode, u32 ctrlmode_supported) { } #endif /* CONFIG_CAN_CALC_BITTIMING */ From patchwork Sat Sep 18 09:56:35 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincent Mailhol X-Patchwork-Id: 12503775 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67438C4332F for ; Sat, 18 Sep 2021 09:57:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 528A360F70 for ; Sat, 18 Sep 2021 09:57:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244768AbhIRJ7T (ORCPT ); Sat, 18 Sep 2021 05:59:19 -0400 Received: from smtp05.smtpout.orange.fr ([80.12.242.127]:63617 "EHLO smtp.smtpout.orange.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244731AbhIRJ7P (ORCPT ); Sat, 18 Sep 2021 05:59:15 -0400 Received: from tomoyo.flets-east.jp ([114.149.34.46]) by smtp.orange.fr with ESMTPA id RX5Zmuh4X1yYBRX6Lm0kHp; Sat, 18 Sep 2021 11:57:51 +0200 X-ME-Helo: tomoyo.flets-east.jp X-ME-Auth: MDU0YmViZGZmMDIzYiBlMiM2NTczNTRjNWZkZTMwOGRiOGQ4ODf3NWI1ZTMyMzdiODlhOQ== X-ME-Date: Sat, 18 Sep 2021 11:57:51 +0200 X-ME-IP: 114.149.34.46 From: Vincent Mailhol To: Marc Kleine-Budde , linux-can@vger.kernel.org Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, =?utf-8?q?Stefan_M?= =?utf-8?q?=C3=A4tje?= , Vincent Mailhol Subject: [PATCH v6 4/6] can: netlink: add interface for CAN-FD Transmitter Delay Compensation (TDC) Date: Sat, 18 Sep 2021 18:56:35 +0900 Message-Id: <20210918095637.20108-5-mailhol.vincent@wanadoo.fr> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210918095637.20108-1-mailhol.vincent@wanadoo.fr> References: <20210918095637.20108-1-mailhol.vincent@wanadoo.fr> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Add the netlink interface for TDC parameters of struct can_tdc_const and can_tdc. Contrary to the can_bittiming(_const) structures for which there is just a single IFLA_CAN(_DATA)_BITTMING(_CONST) entry per structure, here, we create a nested entry IFLA_CAN_TDC. Within this nested entry, additional IFLA_CAN_TDC_TDC* entries are added for each of the TDC parameters of the newly introduced struct can_tdc_const and struct can_tdc. For struct can_tdc_const, these are: IFLA_CAN_TDC_TDCV_MIN IFLA_CAN_TDC_TDCV_MAX IFLA_CAN_TDC_TDCO_MIN IFLA_CAN_TDC_TDCO_MAX IFLA_CAN_TDC_TDCF_MIN IFLA_CAN_TDC_TDCF_MAX For struct can_tdc, these are: IFLA_CAN_TDC_TDCV IFLA_CAN_TDC_TDCO IFLA_CAN_TDC_TDCF This is done so that changes can be applied in the future to the structures without breaking the netlink interface. The TDC netlink logic works as follow: * CAN_CTRLMODE_FD is not provided: - if any TDC parameters are provided: error. - TDC parameters not provided: TDC parameters unchanged. * CAN_CTRLMODE_FD is provided and is false: - TDC is deactivated: both the structure and the CAN_CTRLMODE_TDC_{AUTO,MANUAL} flags are flushed. * CAN_CTRLMODE_FD provided and is true: - CAN_CTRLMODE_TDC_{AUTO,MANUAL} and tdc{v,o,f} not provided: call can_calc_tdco() to automatically decide whether TDC should be activated and, if so, set CAN_CTRLMODE_TDC_AUTO and uses the calculated tdco value. - CAN_CTRLMODE_TDC_AUTO and tdco provided: set CAN_CTRLMODE_TDC_AUTO and use the provided tdco value. Here, tdcv is illegal and tdcf is optional. - CAN_CTRLMODE_TDC_MANUAL and both of tdcv and tdco provided: set CAN_CTRLMODE_TDC_MANUAL and use the provided tdcv and tdco value. Here, tdcf is optional. - CAN_CTRLMODE_TDC_{AUTO,MANUAL} are mutually exclusive. Whenever one flag is turned on, the other will automatically be turned off. Providing both returns an error. - Combination other than the one listed above are illegal and will return an error. N.B. above rules mean that whenever CAN_CTRLMODE_FD is provided, the previous TDC values will be overwritten. The only option to reuse previous TDC value is to not provide CAN_CTRLMODE_FD. All the new parameters are defined as u32. This arbitrary choice is done to mimic the other bittiming values with are also all of type u32. An u16 would have been sufficient to hold the TDC values. This patch completes below series (c.f. [1]): - commit 289ea9e4ae59 ("can: add new CAN FD bittiming parameters: Transmitter Delay Compensation (TDC)") - commit c25cc7993243 ("can: bittiming: add calculation for CAN FD Transmitter Delay Compensation (TDC)") [1] https://lore.kernel.org/linux-can/20210224002008.4158-1-mailhol.vincent@wanadoo.fr/T/#t Signed-off-by: Vincent Mailhol --- drivers/net/can/dev/netlink.c | 213 ++++++++++++++++++++++++++++++- include/uapi/linux/can/netlink.h | 29 ++++- 2 files changed, 235 insertions(+), 7 deletions(-) diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c index e79c9a2ffbfc..c77cc6ae88b6 100644 --- a/drivers/net/can/dev/netlink.c +++ b/drivers/net/can/dev/netlink.c @@ -2,6 +2,7 @@ /* Copyright (C) 2005 Marc Kleine-Budde, Pengutronix * Copyright (C) 2006 Andrey Volkov, Varma Electronics * Copyright (C) 2008-2009 Wolfgang Grandegger + * Copyright (C) 2021 Vincent Mailhol */ #include @@ -19,6 +20,19 @@ static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = { [IFLA_CAN_DATA_BITTIMING] = { .len = sizeof(struct can_bittiming) }, [IFLA_CAN_DATA_BITTIMING_CONST] = { .len = sizeof(struct can_bittiming_const) }, [IFLA_CAN_TERMINATION] = { .type = NLA_U16 }, + [IFLA_CAN_TDC] = { .type = NLA_NESTED }, +}; + +static const struct nla_policy can_tdc_policy[IFLA_CAN_TDC_MAX + 1] = { + [IFLA_CAN_TDC_TDCV_MIN] = { .type = NLA_U32 }, + [IFLA_CAN_TDC_TDCV_MAX] = { .type = NLA_U32 }, + [IFLA_CAN_TDC_TDCO_MIN] = { .type = NLA_U32 }, + [IFLA_CAN_TDC_TDCO_MAX] = { .type = NLA_U32 }, + [IFLA_CAN_TDC_TDCF_MIN] = { .type = NLA_U32 }, + [IFLA_CAN_TDC_TDCF_MAX] = { .type = NLA_U32 }, + [IFLA_CAN_TDC_TDCV] = { .type = NLA_U32 }, + [IFLA_CAN_TDC_TDCO] = { .type = NLA_U32 }, + [IFLA_CAN_TDC_TDCF] = { .type = NLA_U32 }, }; static int can_validate(struct nlattr *tb[], struct nlattr *data[], @@ -30,6 +44,7 @@ static int can_validate(struct nlattr *tb[], struct nlattr *data[], * - nominal/arbitration bittiming * - data bittiming * - control mode with CAN_CTRLMODE_FD set + * - TDC parameters are coherent (details below) */ if (!data) @@ -37,8 +52,43 @@ static int can_validate(struct nlattr *tb[], struct nlattr *data[], if (data[IFLA_CAN_CTRLMODE]) { struct can_ctrlmode *cm = nla_data(data[IFLA_CAN_CTRLMODE]); + u32 tdc_flags = cm->flags & CAN_CTRLMODE_TDC_MASK; is_can_fd = cm->flags & cm->mask & CAN_CTRLMODE_FD; + + /* CAN_CTRLMODE_TDC_{AUTO,MANUAL} are mutually exclusive */ + if (tdc_flags == CAN_CTRLMODE_TDC_MASK) + return -EOPNOTSUPP; + /* If one of the CAN_CTRLMODE_TDC_* flag is set then + * TDC must be set and vice-versa + */ + if (!!tdc_flags != !!data[IFLA_CAN_TDC]) + return -EOPNOTSUPP; + /* If providing TDC parameters, at least TDCO is + * needed. TDCV is needed if and only if + * CAN_CTRLMODE_TDC_MANUAL is set + */ + if (data[IFLA_CAN_TDC]) { + struct nlattr *tb_tdc[IFLA_CAN_TDC_MAX + 1]; + int err; + + err = nla_parse_nested(tb_tdc, IFLA_CAN_TDC_MAX, + data[IFLA_CAN_TDC], + can_tdc_policy, extack); + if (err) + return err; + + if (tb_tdc[IFLA_CAN_TDC_TDCV]) { + if (tdc_flags & CAN_CTRLMODE_TDC_AUTO) + return -EOPNOTSUPP; + } else { + if (tdc_flags & CAN_CTRLMODE_TDC_MANUAL) + return -EOPNOTSUPP; + } + + if (!tb_tdc[IFLA_CAN_TDC_TDCO]) + return -EOPNOTSUPP; + } } if (is_can_fd) { @@ -46,7 +96,7 @@ static int can_validate(struct nlattr *tb[], struct nlattr *data[], return -EOPNOTSUPP; } - if (data[IFLA_CAN_DATA_BITTIMING]) { + if (data[IFLA_CAN_DATA_BITTIMING] || data[IFLA_CAN_TDC]) { if (!is_can_fd) return -EOPNOTSUPP; } @@ -54,11 +104,60 @@ static int can_validate(struct nlattr *tb[], struct nlattr *data[], return 0; } +static int can_tdc_changelink(struct can_priv *priv, const struct nlattr *nla, + struct netlink_ext_ack *extack) +{ + struct nlattr *tb_tdc[IFLA_CAN_TDC_MAX + 1]; + struct can_tdc tdc = { 0 }; + const struct can_tdc_const *tdc_const = priv->tdc_const; + int err; + + if (!tdc_const || !can_tdc_is_enabled(priv)) + return -EOPNOTSUPP; + + err = nla_parse_nested(tb_tdc, IFLA_CAN_TDC_MAX, nla, + can_tdc_policy, extack); + if (err) + return err; + + if (tb_tdc[IFLA_CAN_TDC_TDCV]) { + u32 tdcv = nla_get_u32(tb_tdc[IFLA_CAN_TDC_TDCV]); + + if (tdcv < tdc_const->tdcv_min || tdcv > tdc_const->tdcv_max) + return -EINVAL; + + tdc.tdcv = tdcv; + } + + if (tb_tdc[IFLA_CAN_TDC_TDCO]) { + u32 tdco = nla_get_u32(tb_tdc[IFLA_CAN_TDC_TDCO]); + + if (tdco < tdc_const->tdco_min || tdco > tdc_const->tdco_max) + return -EINVAL; + + tdc.tdco = tdco; + } + + if (tb_tdc[IFLA_CAN_TDC_TDCF]) { + u32 tdcf = nla_get_u32(tb_tdc[IFLA_CAN_TDC_TDCF]); + + if (tdcf < tdc_const->tdcf_min || tdcf > tdc_const->tdcf_max) + return -EINVAL; + + tdc.tdcf = tdcf; + } + + priv->tdc = tdc; + + return 0; +} + static int can_changelink(struct net_device *dev, struct nlattr *tb[], struct nlattr *data[], struct netlink_ext_ack *extack) { struct can_priv *priv = netdev_priv(dev); + u32 tdc_mask = 0; int err; /* We need synchronization with dev->stop() */ @@ -138,7 +237,16 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[], dev->mtu = CAN_MTU; memset(&priv->data_bittiming, 0, sizeof(priv->data_bittiming)); + priv->ctrlmode &= ~CAN_CTRLMODE_TDC_MASK; + memset(&priv->tdc, 0, sizeof(priv->tdc)); } + + tdc_mask = cm->mask & CAN_CTRLMODE_TDC_MASK; + /* CAN_CTRLMODE_TDC_{AUTO,MANUAL} are mutually + * exclusive: make sure to turn the other one off + */ + if (tdc_mask) + priv->ctrlmode &= cm->flags | ~CAN_CTRLMODE_TDC_MASK; } if (data[IFLA_CAN_RESTART_MS]) { @@ -187,10 +295,26 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[], return -EINVAL; } - memcpy(&priv->data_bittiming, &dbt, sizeof(dbt)); + memset(&priv->tdc, 0, sizeof(priv->tdc)); + if (data[IFLA_CAN_TDC]) { + /* TDC parameters are provided: use them */ + err = can_tdc_changelink(priv, data[IFLA_CAN_TDC], + extack); + if (err) { + priv->ctrlmode &= ~CAN_CTRLMODE_TDC_MASK; + return err; + } + } else if (!tdc_mask) { + /* Neither of TDC parameters nor TDC flags are + * provided: do calculation + */ + can_calc_tdco(&priv->tdc, priv->tdc_const, &priv->data_bittiming, + &priv->ctrlmode, priv->ctrlmode_supported); + } /* else: both CAN_CTRLMODE_TDC_{AUTO,MANUAL} are explicitly + * turned off. TDC is disabled: do nothing + */ - can_calc_tdco(&priv->tdc, priv->tdc_const, &priv->data_bittiming, - &priv->ctrlmode, priv->ctrlmode_supported); + memcpy(&priv->data_bittiming, &dbt, sizeof(dbt)); if (priv->do_set_data_bittiming) { /* Finally, set the bit-timing registers */ @@ -227,6 +351,37 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[], return 0; } +static size_t can_tdc_get_size(const struct net_device *dev) +{ + struct can_priv *priv = netdev_priv(dev); + size_t size; + + if (!priv->tdc_const) + return 0; + + size = nla_total_size(0); /* nest IFLA_CAN_TDC */ + if (priv->ctrlmode_supported & CAN_CTRLMODE_TDC_MANUAL) { + size += nla_total_size(sizeof(u32)); /* IFLA_CAN_TDCV_MIN */ + size += nla_total_size(sizeof(u32)); /* IFLA_CAN_TDCV_MAX */ + } + size += nla_total_size(sizeof(u32)); /* IFLA_CAN_TDCO_MIN */ + size += nla_total_size(sizeof(u32)); /* IFLA_CAN_TDCO_MAX */ + if (priv->tdc_const->tdcf_max) { + size += nla_total_size(sizeof(u32)); /* IFLA_CAN_TDCF_MIN */ + size += nla_total_size(sizeof(u32)); /* IFLA_CAN_TDCF_MAX */ + } + + if (can_tdc_is_enabled(priv)) { + if (priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL) + size += nla_total_size(sizeof(u32)); /* IFLA_CAN_TDCV */ + size += nla_total_size(sizeof(u32)); /* IFLA_CAN_TDCO */ + if (priv->tdc_const->tdcf_max) + size += nla_total_size(sizeof(u32)); /* IFLA_CAN_TDCF */ + } + + return size; +} + static size_t can_get_size(const struct net_device *dev) { struct can_priv *priv = netdev_priv(dev); @@ -258,10 +413,56 @@ static size_t can_get_size(const struct net_device *dev) size += nla_total_size(sizeof(*priv->data_bitrate_const) * priv->data_bitrate_const_cnt); size += sizeof(priv->bitrate_max); /* IFLA_CAN_BITRATE_MAX */ + size += can_tdc_get_size(dev); /* IFLA_CAN_TDC */ return size; } +static int can_tdc_fill_info(struct sk_buff *skb, const struct net_device *dev) +{ + struct nlattr *nest; + struct can_priv *priv = netdev_priv(dev); + struct can_tdc *tdc = &priv->tdc; + const struct can_tdc_const *tdc_const = priv->tdc_const; + + if (!tdc_const) + return 0; + + nest = nla_nest_start(skb, IFLA_CAN_TDC); + if (!nest) + return -EMSGSIZE; + + if (priv->ctrlmode_supported & CAN_CTRLMODE_TDC_MANUAL && + (nla_put_u32(skb, IFLA_CAN_TDC_TDCV_MIN, tdc_const->tdcv_min) || + nla_put_u32(skb, IFLA_CAN_TDC_TDCV_MAX, tdc_const->tdcv_max))) + goto err_cancel; + if (nla_put_u32(skb, IFLA_CAN_TDC_TDCO_MIN, tdc_const->tdco_min) || + nla_put_u32(skb, IFLA_CAN_TDC_TDCO_MAX, tdc_const->tdco_max)) + goto err_cancel; + if (tdc_const->tdcf_max && + (nla_put_u32(skb, IFLA_CAN_TDC_TDCF_MIN, tdc_const->tdcf_min) || + nla_put_u32(skb, IFLA_CAN_TDC_TDCF_MAX, tdc_const->tdcf_max))) + goto err_cancel; + + if (can_tdc_is_enabled(priv)) { + if (priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL && + nla_put_u32(skb, IFLA_CAN_TDC_TDCV, tdc->tdcv)) + goto err_cancel; + if (nla_put_u32(skb, IFLA_CAN_TDC_TDCO, tdc->tdco)) + goto err_cancel; + if (tdc_const->tdcf_max && + nla_put_u32(skb, IFLA_CAN_TDC_TDCF, tdc->tdcf)) + goto err_cancel; + } + + nla_nest_end(skb, nest); + return 0; + +err_cancel: + nla_nest_cancel(skb, nest); + return -EMSGSIZE; +} + static int can_fill_info(struct sk_buff *skb, const struct net_device *dev) { struct can_priv *priv = netdev_priv(dev); @@ -319,7 +520,9 @@ static int can_fill_info(struct sk_buff *skb, const struct net_device *dev) (nla_put(skb, IFLA_CAN_BITRATE_MAX, sizeof(priv->bitrate_max), - &priv->bitrate_max)) + &priv->bitrate_max)) || + + (can_tdc_fill_info(skb, dev)) ) return -EMSGSIZE; diff --git a/include/uapi/linux/can/netlink.h b/include/uapi/linux/can/netlink.h index 004cd09a7d49..75b85c60efb2 100644 --- a/include/uapi/linux/can/netlink.h +++ b/include/uapi/linux/can/netlink.h @@ -136,10 +136,35 @@ enum { IFLA_CAN_BITRATE_CONST, IFLA_CAN_DATA_BITRATE_CONST, IFLA_CAN_BITRATE_MAX, - __IFLA_CAN_MAX + IFLA_CAN_TDC, + + /* add new constants above here */ + __IFLA_CAN_MAX, + IFLA_CAN_MAX = __IFLA_CAN_MAX - 1 }; -#define IFLA_CAN_MAX (__IFLA_CAN_MAX - 1) +/* + * CAN FD Transmitter Delay Compensation (TDC) + * + * Please refer to struct can_tdc_const and can_tdc in + * include/linux/can/bittiming.h for further details. + */ +enum { + IFLA_CAN_TDC_UNSPEC, + IFLA_CAN_TDC_TDCV_MIN, /* u32 */ + IFLA_CAN_TDC_TDCV_MAX, /* u32 */ + IFLA_CAN_TDC_TDCO_MIN, /* u32 */ + IFLA_CAN_TDC_TDCO_MAX, /* u32 */ + IFLA_CAN_TDC_TDCF_MIN, /* u32 */ + IFLA_CAN_TDC_TDCF_MAX, /* u32 */ + IFLA_CAN_TDC_TDCV, /* u32 */ + IFLA_CAN_TDC_TDCO, /* u32 */ + IFLA_CAN_TDC_TDCF, /* u32 */ + + /* add new constants above here */ + __IFLA_CAN_TDC, + IFLA_CAN_TDC_MAX = __IFLA_CAN_TDC - 1 +}; /* u16 termination range: 1..65535 Ohms */ #define CAN_TERMINATION_DISABLED 0 From patchwork Sat Sep 18 09:56:36 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Vincent Mailhol X-Patchwork-Id: 12503777 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 48C28C433F5 for ; Sat, 18 Sep 2021 09:58:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 31E9960FC0 for ; Sat, 18 Sep 2021 09:58:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244862AbhIRJ70 (ORCPT ); Sat, 18 Sep 2021 05:59:26 -0400 Received: from smtp05.smtpout.orange.fr ([80.12.242.127]:59130 "EHLO smtp.smtpout.orange.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244796AbhIRJ7V (ORCPT ); Sat, 18 Sep 2021 05:59:21 -0400 Received: from tomoyo.flets-east.jp ([114.149.34.46]) by smtp.orange.fr with ESMTPA id RX5Zmuh4X1yYBRX6Ym0kIi; Sat, 18 Sep 2021 11:57:57 +0200 X-ME-Helo: tomoyo.flets-east.jp X-ME-Auth: MDU0YmViZGZmMDIzYiBlMiM2NTczNTRjNWZkZTMwOGRiOGQ4ODf3NWI1ZTMyMzdiODlhOQ== X-ME-Date: Sat, 18 Sep 2021 11:57:57 +0200 X-ME-IP: 114.149.34.46 From: Vincent Mailhol To: Marc Kleine-Budde , linux-can@vger.kernel.org Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, =?utf-8?q?Stefan_M?= =?utf-8?q?=C3=A4tje?= , Vincent Mailhol , =?utf-8?q?Stefan_M=C3=A4tje?= Subject: [PATCH v6 5/6] can: netlink: add can_priv::do_get_auto_tdcv() to retrieve tdcv from device Date: Sat, 18 Sep 2021 18:56:36 +0900 Message-Id: <20210918095637.20108-6-mailhol.vincent@wanadoo.fr> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210918095637.20108-1-mailhol.vincent@wanadoo.fr> References: <20210918095637.20108-1-mailhol.vincent@wanadoo.fr> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Some CAN device can measure the TDCV (Transmission Delay Compensation Value) automatically for each transmitted CAN frames. A callback function do_get_auto_tdcv() is added to retrieve that value. This function is used only if CAN_CTRLMODE_TDC_AUTO is enabled (if CAN_CTRLMODE_TDC_MANUAL is selected, the TDCV value is provided by the user). If the device does not support reporting of TDCV, do_get_auto_tdcv() should be set to NULL and TDCV will not be reported by the netlink interface. On success, do_get_auto_tdcv() shall return 0. If the value can not be measured by the device, for example because network is down or because no frames were transmitted yet, can_priv::do_get_auto_tdcv() shall return a negative error code (e.g. -EINVAL) to signify that the value is not yet available. In such cases, TDCV is not reported by the netlink interface. CC: Stefan Mätje Signed-off-by: Vincent Mailhol --- drivers/net/can/dev/netlink.c | 15 ++++++++++++--- include/linux/can/dev.h | 1 + 2 files changed, 13 insertions(+), 3 deletions(-) diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c index c77cc6ae88b6..95cca4e5251f 100644 --- a/drivers/net/can/dev/netlink.c +++ b/drivers/net/can/dev/netlink.c @@ -372,7 +372,8 @@ static size_t can_tdc_get_size(const struct net_device *dev) } if (can_tdc_is_enabled(priv)) { - if (priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL) + if (priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL || + priv->do_get_auto_tdcv) size += nla_total_size(sizeof(u32)); /* IFLA_CAN_TDCV */ size += nla_total_size(sizeof(u32)); /* IFLA_CAN_TDCO */ if (priv->tdc_const->tdcf_max) @@ -445,8 +446,16 @@ static int can_tdc_fill_info(struct sk_buff *skb, const struct net_device *dev) goto err_cancel; if (can_tdc_is_enabled(priv)) { - if (priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL && - nla_put_u32(skb, IFLA_CAN_TDC_TDCV, tdc->tdcv)) + u32 tdcv; + int err = -EINVAL; + + if (priv->ctrlmode & CAN_CTRLMODE_TDC_MANUAL) { + tdcv = tdc->tdcv; + err = 0; + } else if (priv->do_get_auto_tdcv) { + err = priv->do_get_auto_tdcv(dev, &tdcv); + } + if (!err && nla_put_u32(skb, IFLA_CAN_TDC_TDCV, tdcv)) goto err_cancel; if (nla_put_u32(skb, IFLA_CAN_TDC_TDCO, tdc->tdco)) goto err_cancel; diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h index 6dacbbb41e68..b4aa0f048cab 100644 --- a/include/linux/can/dev.h +++ b/include/linux/can/dev.h @@ -82,6 +82,7 @@ struct can_priv { enum can_state *state); int (*do_get_berr_counter)(const struct net_device *dev, struct can_berr_counter *bec); + int (*do_get_auto_tdcv)(const struct net_device *dev, u32 *tdcv); unsigned int echo_skb_max; struct sk_buff **echo_skb; From patchwork Sat Sep 18 09:56:37 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Vincent Mailhol X-Patchwork-Id: 12503779 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EA70FC433F5 for ; Sat, 18 Sep 2021 09:58:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CD8FD60FBF for ; Sat, 18 Sep 2021 09:58:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244997AbhIRJ75 (ORCPT ); Sat, 18 Sep 2021 05:59:57 -0400 Received: from smtp05.smtpout.orange.fr ([80.12.242.127]:59027 "EHLO smtp.smtpout.orange.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244985AbhIRJ7b (ORCPT ); Sat, 18 Sep 2021 05:59:31 -0400 Received: from tomoyo.flets-east.jp ([114.149.34.46]) by smtp.orange.fr with ESMTPA id RX5Zmuh4X1yYBRX6im0kJV; Sat, 18 Sep 2021 11:58:07 +0200 X-ME-Helo: tomoyo.flets-east.jp X-ME-Auth: MDU0YmViZGZmMDIzYiBlMiM2NTczNTRjNWZkZTMwOGRiOGQ4ODf3NWI1ZTMyMzdiODlhOQ== X-ME-Date: Sat, 18 Sep 2021 11:58:07 +0200 X-ME-IP: 114.149.34.46 From: Vincent Mailhol To: Marc Kleine-Budde , linux-can@vger.kernel.org Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, =?utf-8?q?Stefan_M?= =?utf-8?q?=C3=A4tje?= , Vincent Mailhol Subject: [PATCH v6 6/6] can: dev: add can_tdc_get_relative_tdco() helper function Date: Sat, 18 Sep 2021 18:56:37 +0900 Message-Id: <20210918095637.20108-7-mailhol.vincent@wanadoo.fr> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210918095637.20108-1-mailhol.vincent@wanadoo.fr> References: <20210918095637.20108-1-mailhol.vincent@wanadoo.fr> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org struct can_tdc::tdco represents the absolute offset from TDCV. Some controllers use instead an offset relative to the Sample Point (SP) such that: | SSP = TDCV + absolute TDCO | = TDCV + SP + relative TDCO Consequently: | relative TDCO = absolute TDCO - SP The function can_tdc_get_relative_tdco() allow to retrieve this relative TDCO value. CC: Stefan Mätje Signed-off-by: Vincent Mailhol --- Hi Marc, As Stefan pointed out in: https://lore.kernel.org/linux-can/79691916e4280970f583a54cd5010ece025a1c53.c amel@esd.eu/ it seems that no so many CAN devices are using the relative TDCO (maybe the ESDACC is the only one?). Depending on the output of your discussion with Microchip and if the mcp25xxfd is indeed using an absolute tdco, it might make sense to drop this patch from the series. Yours sincerely, Vincent --- include/linux/can/dev.h | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h index b4aa0f048cab..45f19d9db5ca 100644 --- a/include/linux/can/dev.h +++ b/include/linux/can/dev.h @@ -102,6 +102,35 @@ static inline bool can_tdc_is_enabled(const struct can_priv *priv) return !!(priv->ctrlmode & CAN_CTRLMODE_TDC_MASK); } +/* + * can_get_relative_tdco() - TDCO relative to the sample point + * + * struct can_tdc::tdco represents the absolute offset from TDCV. Some + * controllers use instead an offset relative to the Sample Point (SP) + * such that: + * + * SSP = TDCV + absolute TDCO + * = TDCV + SP + relative TDCO + * + * -+----------- one bit ----------+-- TX pin + * |<--- Sample Point --->| + * + * --+----------- one bit ----------+-- RX pin + * |<-------- TDCV -------->| + * |<------------------------>| absolute TDCO + * |<--- Sample Point --->| + * | |<->| relative TDCO + * |<------------- Secondary Sample Point ------------>| + */ +static inline s32 can_get_relative_tdco(const struct can_priv *priv) +{ + const struct can_bittiming *dbt = &priv->data_bittiming; + s32 sample_point_in_tc = (CAN_SYNC_SEG + dbt->prop_seg + + dbt->phase_seg1) * dbt->brp; + + return (s32)priv->tdc.tdco - sample_point_in_tc; +} + /* helper to define static CAN controller features at device creation time */ static inline void can_set_static_ctrlmode(struct net_device *dev, u32 static_mode)