diff options
Diffstat (limited to 'drivers/net/can/dev/dev.c')
| -rw-r--r-- | drivers/net/can/dev/dev.c | 261 |
1 files changed, 0 insertions, 261 deletions
diff --git a/drivers/net/can/dev/dev.c b/drivers/net/can/dev/dev.c index 3486704c8a95..1b3ab95b3fd1 100644 --- a/drivers/net/can/dev/dev.c +++ b/drivers/net/can/dev/dev.c @@ -58,267 +58,6 @@ u8 can_fd_len2dlc(u8 len) } EXPORT_SYMBOL_GPL(can_fd_len2dlc); -#ifdef CONFIG_CAN_CALC_BITTIMING -#define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */ - -/* Bit-timing calculation derived from: - * - * Code based on LinCAN sources and H8S2638 project - * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz - * Copyright 2005 Stanislav Marek - * email: pisa@cmp.felk.cvut.cz - * - * Calculates proper bit-timing parameters for a specified bit-rate - * and sample-point, which can then be used to set the bit-timing - * registers of the CAN controller. You can find more information - * in the header file linux/can/netlink.h. - */ -static int -can_update_sample_point(const struct can_bittiming_const *btc, - unsigned int sample_point_nominal, unsigned int tseg, - unsigned int *tseg1_ptr, unsigned int *tseg2_ptr, - unsigned int *sample_point_error_ptr) -{ - unsigned int sample_point_error, best_sample_point_error = UINT_MAX; - unsigned int sample_point, best_sample_point = 0; - unsigned int tseg1, tseg2; - int i; - - for (i = 0; i <= 1; i++) { - tseg2 = tseg + CAN_SYNC_SEG - - (sample_point_nominal * (tseg + CAN_SYNC_SEG)) / - 1000 - i; - tseg2 = clamp(tseg2, btc->tseg2_min, btc->tseg2_max); - tseg1 = tseg - tseg2; - if (tseg1 > btc->tseg1_max) { - tseg1 = btc->tseg1_max; - tseg2 = tseg - tseg1; - } - - sample_point = 1000 * (tseg + CAN_SYNC_SEG - tseg2) / - (tseg + CAN_SYNC_SEG); - sample_point_error = abs(sample_point_nominal - sample_point); - - if (sample_point <= sample_point_nominal && - sample_point_error < best_sample_point_error) { - best_sample_point = sample_point; - best_sample_point_error = sample_point_error; - *tseg1_ptr = tseg1; - *tseg2_ptr = tseg2; - } - } - - if (sample_point_error_ptr) - *sample_point_error_ptr = best_sample_point_error; - - return best_sample_point; -} - -static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt, - const struct can_bittiming_const *btc) -{ - struct can_priv *priv = netdev_priv(dev); - unsigned int bitrate; /* current bitrate */ - unsigned int bitrate_error; /* difference between current and nominal value */ - unsigned int best_bitrate_error = UINT_MAX; - unsigned int sample_point_error; /* difference between current and nominal value */ - unsigned int best_sample_point_error = UINT_MAX; - unsigned int sample_point_nominal; /* nominal sample point */ - unsigned int best_tseg = 0; /* current best value for tseg */ - unsigned int best_brp = 0; /* current best value for brp */ - unsigned int brp, tsegall, tseg, tseg1 = 0, tseg2 = 0; - u64 v64; - - /* Use CiA recommended sample points */ - if (bt->sample_point) { - sample_point_nominal = bt->sample_point; - } else { - if (bt->bitrate > 800000) - sample_point_nominal = 750; - else if (bt->bitrate > 500000) - sample_point_nominal = 800; - else - sample_point_nominal = 875; - } - - /* tseg even = round down, odd = round up */ - for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1; - tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) { - tsegall = CAN_SYNC_SEG + tseg / 2; - - /* Compute all possible tseg choices (tseg=tseg1+tseg2) */ - brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2; - - /* choose brp step which is possible in system */ - brp = (brp / btc->brp_inc) * btc->brp_inc; - if (brp < btc->brp_min || brp > btc->brp_max) - continue; - - bitrate = priv->clock.freq / (brp * tsegall); - bitrate_error = abs(bt->bitrate - bitrate); - - /* tseg brp biterror */ - if (bitrate_error > best_bitrate_error) - continue; - - /* reset sample point error if we have a better bitrate */ - if (bitrate_error < best_bitrate_error) - best_sample_point_error = UINT_MAX; - - can_update_sample_point(btc, sample_point_nominal, tseg / 2, - &tseg1, &tseg2, &sample_point_error); - if (sample_point_error > best_sample_point_error) - continue; - - best_sample_point_error = sample_point_error; - best_bitrate_error = bitrate_error; - best_tseg = tseg / 2; - best_brp = brp; - - if (bitrate_error == 0 && sample_point_error == 0) - break; - } - - if (best_bitrate_error) { - /* Error in one-tenth of a percent */ - v64 = (u64)best_bitrate_error * 1000; - do_div(v64, bt->bitrate); - bitrate_error = (u32)v64; - if (bitrate_error > CAN_CALC_MAX_ERROR) { - netdev_err(dev, - "bitrate error %d.%d%% too high\n", - bitrate_error / 10, bitrate_error % 10); - return -EDOM; - } - netdev_warn(dev, "bitrate error %d.%d%%\n", - bitrate_error / 10, bitrate_error % 10); - } - - /* real sample point */ - bt->sample_point = can_update_sample_point(btc, sample_point_nominal, - best_tseg, &tseg1, &tseg2, - NULL); - - v64 = (u64)best_brp * 1000 * 1000 * 1000; - do_div(v64, priv->clock.freq); - bt->tq = (u32)v64; - bt->prop_seg = tseg1 / 2; - bt->phase_seg1 = tseg1 - bt->prop_seg; - bt->phase_seg2 = tseg2; - - /* check for sjw user settings */ - if (!bt->sjw || !btc->sjw_max) { - bt->sjw = 1; - } else { - /* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */ - if (bt->sjw > btc->sjw_max) - bt->sjw = btc->sjw_max; - /* bt->sjw must not be higher than tseg2 */ - if (tseg2 < bt->sjw) - bt->sjw = tseg2; - } - - bt->brp = best_brp; - - /* real bitrate */ - bt->bitrate = priv->clock.freq / - (bt->brp * (CAN_SYNC_SEG + tseg1 + tseg2)); - - return 0; -} -#else /* !CONFIG_CAN_CALC_BITTIMING */ -static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt, - const struct can_bittiming_const *btc) -{ - netdev_err(dev, "bit-timing calculation not available\n"); - return -EINVAL; -} -#endif /* CONFIG_CAN_CALC_BITTIMING */ - -/* 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(struct net_device *dev, struct can_bittiming *bt, - const struct can_bittiming_const *btc) -{ - struct can_priv *priv = netdev_priv(dev); - int tseg1, alltseg; - u64 brp64; - - tseg1 = bt->prop_seg + bt->phase_seg1; - if (!bt->sjw) - bt->sjw = 1; - if (bt->sjw > btc->sjw_max || - tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max || - bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max) - return -ERANGE; - - 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 || bt->brp > btc->brp_max) - return -EINVAL; - - alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1; - bt->bitrate = priv->clock.freq / (bt->brp * alltseg); - bt->sample_point = ((tseg1 + 1) * 1000) / alltseg; - - return 0; -} - -/* Checks the validity of predefined bitrate settings */ -static int -can_validate_bitrate(struct net_device *dev, struct can_bittiming *bt, - const u32 *bitrate_const, - const unsigned int bitrate_const_cnt) -{ - struct can_priv *priv = netdev_priv(dev); - unsigned int i; - - for (i = 0; i < bitrate_const_cnt; i++) { - if (bt->bitrate == bitrate_const[i]) - break; - } - - if (i >= priv->bitrate_const_cnt) - return -EINVAL; - - return 0; -} - -static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt, - const struct can_bittiming_const *btc, - const u32 *bitrate_const, - const unsigned int bitrate_const_cnt) -{ - int err; - - /* 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) - err = can_calc_bittiming(dev, bt, btc); - else if (bt->tq && !bt->bitrate && btc) - err = can_fixup_bittiming(dev, bt, btc); - else if (!bt->tq && bt->bitrate && bitrate_const) - err = can_validate_bitrate(dev, bt, bitrate_const, - bitrate_const_cnt); - else - err = -EINVAL; - - return err; -} - static void can_update_state_error_stats(struct net_device *dev, enum can_state new_state) { |