// SPDX-License-Identifier: GPL-2.0-only /* Copyright (C) 2005 Marc Kleine-Budde, Pengutronix * Copyright (C) 2006 Andrey Volkov, Varma Electronics * Copyright (C) 2008-2009 Wolfgang Grandegger * Copyright (c) 2025 Vincent Mailhol */ #include void can_sjw_set_default(struct can_bittiming *bt) { if (bt->sjw) return; /* If user space provides no sjw, use sane default of phase_seg2 / 2 */ bt->sjw = max(1U, min(bt->phase_seg1, bt->phase_seg2 / 2)); } int can_sjw_check(const struct net_device *dev, const struct can_bittiming *bt, const struct can_bittiming_const *btc, struct netlink_ext_ack *extack) { if (bt->sjw > btc->sjw_max) { NL_SET_ERR_MSG_FMT(extack, "sjw: %u greater than max sjw: %u", bt->sjw, btc->sjw_max); return -EINVAL; } if (bt->sjw > bt->phase_seg1) { NL_SET_ERR_MSG_FMT(extack, "sjw: %u greater than phase-seg1: %u", bt->sjw, bt->phase_seg1); return -EINVAL; } if (bt->sjw > bt->phase_seg2) { NL_SET_ERR_MSG_FMT(extack, "sjw: %u greater than phase-seg2: %u", bt->sjw, bt->phase_seg2); return -EINVAL; } return 0; } /* Checks the validity of the specified bit-timing parameters prop_seg, * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate * prescaler value brp. You can find more information in the header * file linux/can/netlink.h. */ static int can_fixup_bittiming(const struct net_device *dev, struct can_bittiming *bt, const struct can_bittiming_const *btc, struct netlink_ext_ack *extack) { const unsigned int tseg1 = bt->prop_seg + bt->phase_seg1; const struct can_priv *priv = netdev_priv(dev); u64 brp64; int err; if (tseg1 < btc->tseg1_min) { NL_SET_ERR_MSG_FMT(extack, "prop-seg + phase-seg1: %u less than tseg1-min: %u", tseg1, btc->tseg1_min); return -EINVAL; } if (tseg1 > btc->tseg1_max) { NL_SET_ERR_MSG_FMT(extack, "prop-seg + phase-seg1: %u greater than tseg1-max: %u", tseg1, btc->tseg1_max); return -EINVAL; } if (bt->phase_seg2 < btc->tseg2_min) { NL_SET_ERR_MSG_FMT(extack, "phase-seg2: %u less than tseg2-min: %u", bt->phase_seg2, btc->tseg2_min); return -EINVAL; } if (bt->phase_seg2 > btc->tseg2_max) { NL_SET_ERR_MSG_FMT(extack, "phase-seg2: %u greater than tseg2-max: %u", bt->phase_seg2, btc->tseg2_max); return -EINVAL; } can_sjw_set_default(bt); err = can_sjw_check(dev, bt, btc, extack); if (err) return err; brp64 = (u64)priv->clock.freq * (u64)bt->tq; if (btc->brp_inc > 1) do_div(brp64, btc->brp_inc); brp64 += 500000000UL - 1; do_div(brp64, 1000000000UL); /* the practicable BRP */ if (btc->brp_inc > 1) brp64 *= btc->brp_inc; bt->brp = (u32)brp64; if (bt->brp < btc->brp_min) { NL_SET_ERR_MSG_FMT(extack, "resulting brp: %u less than brp-min: %u", bt->brp, btc->brp_min); return -EINVAL; } if (bt->brp > btc->brp_max) { NL_SET_ERR_MSG_FMT(extack, "resulting brp: %u greater than brp-max: %u", bt->brp, btc->brp_max); return -EINVAL; } bt->bitrate = priv->clock.freq / (bt->brp * can_bit_time(bt)); bt->sample_point = ((CAN_SYNC_SEG + tseg1) * 1000) / can_bit_time(bt); bt->tq = DIV_U64_ROUND_CLOSEST(mul_u32_u32(bt->brp, NSEC_PER_SEC), priv->clock.freq); return 0; } /* Checks the validity of predefined bitrate settings */ static int can_validate_bitrate(const struct net_device *dev, const struct can_bittiming *bt, const u32 *bitrate_const, const unsigned int bitrate_const_cnt, struct netlink_ext_ack *extack) { unsigned int i; for (i = 0; i < bitrate_const_cnt; i++) { if (bt->bitrate == bitrate_const[i]) return 0; } NL_SET_ERR_MSG_FMT(extack, "bitrate %u bps not supported", bt->brp); return -EINVAL; } int can_get_bittiming(const struct net_device *dev, struct can_bittiming *bt, const struct can_bittiming_const *btc, const u32 *bitrate_const, const unsigned int bitrate_const_cnt, struct netlink_ext_ack *extack) { /* Depending on the given can_bittiming parameter structure the CAN * timing parameters are calculated based on the provided bitrate OR * alternatively the CAN timing parameters (tq, prop_seg, etc.) are * provided directly which are then checked and fixed up. */ if (!bt->tq && bt->bitrate && btc) return can_calc_bittiming(dev, bt, btc, extack); if (bt->tq && !bt->bitrate && btc) return can_fixup_bittiming(dev, bt, btc, extack); if (!bt->tq && bt->bitrate && bitrate_const) return can_validate_bitrate(dev, bt, bitrate_const, bitrate_const_cnt, extack); return -EINVAL; } int can_validate_pwm_bittiming(const struct net_device *dev, const struct can_pwm *pwm, struct netlink_ext_ack *extack) { const struct can_priv *priv = netdev_priv(dev); u32 xl_bit_time_tqmin = can_bit_time_tqmin(&priv->xl.data_bittiming); u32 nom_bit_time_tqmin = can_bit_time_tqmin(&priv->bittiming); u32 pwms_ns = can_tqmin_to_ns(pwm->pwms, priv->clock.freq); u32 pwml_ns = can_tqmin_to_ns(pwm->pwml, priv->clock.freq); if (pwms_ns + pwml_ns > CAN_PWM_NS_MAX) { NL_SET_ERR_MSG_FMT(extack, "The PWM symbol duration: %u ns may not exceed %u ns", pwms_ns + pwml_ns, CAN_PWM_NS_MAX); return -EINVAL; } if (pwms_ns < CAN_PWM_DECODE_NS) { NL_SET_ERR_MSG_FMT(extack, "PWMS: %u ns shall be at least %u ns", pwms_ns, CAN_PWM_DECODE_NS); return -EINVAL; } if (pwm->pwms >= pwm->pwml) { NL_SET_ERR_MSG_FMT(extack, "PWMS: %u tqmin shall be smaller than PWML: %u tqmin", pwm->pwms, pwm->pwml); return -EINVAL; } if (pwml_ns - pwms_ns < 2 * CAN_PWM_DECODE_NS) { NL_SET_ERR_MSG_FMT(extack, "At least %u ns shall separate PWMS: %u ns from PMWL: %u ns", 2 * CAN_PWM_DECODE_NS, pwms_ns, pwml_ns); return -EINVAL; } if (xl_bit_time_tqmin % (pwm->pwms + pwm->pwml) != 0) { NL_SET_ERR_MSG_FMT(extack, "PWM duration: %u tqmin does not divide XL's bit time: %u tqmin", pwm->pwms + pwm->pwml, xl_bit_time_tqmin); return -EINVAL; } if (pwm->pwmo >= pwm->pwms + pwm->pwml) { NL_SET_ERR_MSG_FMT(extack, "PWMO: %u tqmin can not be greater than PWMS + PWML: %u tqmin", pwm->pwmo, pwm->pwms + pwm->pwml); return -EINVAL; } if (nom_bit_time_tqmin % (pwm->pwms + pwm->pwml) != pwm->pwmo) { NL_SET_ERR_MSG_FMT(extack, "Can not assemble nominal bit time: %u tqmin out of PWMS + PMWL and PWMO", nom_bit_time_tqmin); return -EINVAL; } return 0; }