Merge pull request #444 from marckleinebudde/can-calc-bittiming-v6.3
can-calc-bit-timing: import bit timing calculation algorithm from v6.3pull/445/head
Marc Kleine-Budde
GitHub
commit
90baa696cd
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@ -49,7 +49,8 @@ EXTRA_DIST += \
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calc-bit-timing/can-calc-bit-timing-v3_18.c \
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calc-bit-timing/can-calc-bit-timing-v4_8.c \
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calc-bit-timing/can-calc-bit-timing-v5_16.c \
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calc-bit-timing/can-calc-bit-timing-v5_19.c
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calc-bit-timing/can-calc-bit-timing-v5_19.c \
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calc-bit-timing/can-calc-bit-timing-v6_3.c
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mcp251xfd_dump_SOURCES = \
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mcp251xfd/mcp251xfd-dev-coredump.c \
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@ -0,0 +1,290 @@
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/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* imported from v6.3-rc1~162^2~124^2^2~1
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*
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*/
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void can_sjw_set_default(struct can_bittiming *bt)
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{
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if (bt->sjw)
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return;
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/* If user space provides no sjw, use sane default of phase_seg2 / 2 */
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bt->sjw = max(1U, min(bt->phase_seg1, bt->phase_seg2 / 2));
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}
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int can_sjw_check(const struct net_device *dev, const struct can_bittiming *bt,
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const struct can_bittiming_const *btc, struct netlink_ext_ack *extack)
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{
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if (bt->sjw > btc->sjw_max) {
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NL_SET_ERR_MSG_FMT(extack, "sjw: %u greater than max sjw: %u",
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bt->sjw, btc->sjw_max);
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return -EINVAL;
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}
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if (bt->sjw > bt->phase_seg1) {
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NL_SET_ERR_MSG_FMT(extack,
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"sjw: %u greater than phase-seg1: %u",
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bt->sjw, bt->phase_seg1);
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return -EINVAL;
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}
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if (bt->sjw > bt->phase_seg2) {
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NL_SET_ERR_MSG_FMT(extack,
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"sjw: %u greater than phase-seg2: %u",
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bt->sjw, bt->phase_seg2);
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return -EINVAL;
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}
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return 0;
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}
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/*
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* can_bit_time() - Duration of one bit
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*
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* Please refer to ISO 11898-1:2015, section 11.3.1.1 "Bit time" for
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* additional information.
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*
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* Return: the number of time quanta in one bit.
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*/
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static inline unsigned int can_bit_time(const struct can_bittiming *bt)
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{
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return CAN_SYNC_SEG + bt->prop_seg + bt->phase_seg1 + bt->phase_seg2;
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}
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/* Copyright (C) 2005 Marc Kleine-Budde, Pengutronix
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* Copyright (C) 2006 Andrey Volkov, Varma Electronics
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* Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
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*/
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/* Bit-timing calculation derived from:
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*
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* Code based on LinCAN sources and H8S2638 project
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* Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
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* Copyright 2005 Stanislav Marek
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* email: pisa@cmp.felk.cvut.cz
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*
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* Calculates proper bit-timing parameters for a specified bit-rate
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* and sample-point, which can then be used to set the bit-timing
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* registers of the CAN controller. You can find more information
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* in the header file linux/can/netlink.h.
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*/
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static int
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can_update_sample_point(const struct can_bittiming_const *btc,
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const unsigned int sample_point_nominal, const unsigned int tseg,
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unsigned int *tseg1_ptr, unsigned int *tseg2_ptr,
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unsigned int *sample_point_error_ptr)
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{
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unsigned int sample_point_error, best_sample_point_error = UINT_MAX;
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unsigned int sample_point, best_sample_point = 0;
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unsigned int tseg1, tseg2;
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int i;
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for (i = 0; i <= 1; i++) {
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tseg2 = tseg + CAN_SYNC_SEG -
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(sample_point_nominal * (tseg + CAN_SYNC_SEG)) /
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1000 - i;
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tseg2 = clamp(tseg2, btc->tseg2_min, btc->tseg2_max);
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tseg1 = tseg - tseg2;
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if (tseg1 > btc->tseg1_max) {
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tseg1 = btc->tseg1_max;
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tseg2 = tseg - tseg1;
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}
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sample_point = 1000 * (tseg + CAN_SYNC_SEG - tseg2) /
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(tseg + CAN_SYNC_SEG);
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sample_point_error = abs(sample_point_nominal - sample_point);
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if (sample_point <= sample_point_nominal &&
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sample_point_error < best_sample_point_error) {
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best_sample_point = sample_point;
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best_sample_point_error = sample_point_error;
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*tseg1_ptr = tseg1;
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*tseg2_ptr = tseg2;
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}
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}
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if (sample_point_error_ptr)
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*sample_point_error_ptr = best_sample_point_error;
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return best_sample_point;
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}
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int can_calc_bittiming(const struct net_device *dev, struct can_bittiming *bt,
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const struct can_bittiming_const *btc, struct netlink_ext_ack *extack)
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{
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struct can_priv *priv = netdev_priv(dev);
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unsigned int bitrate; /* current bitrate */
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unsigned int bitrate_error; /* difference between current and nominal value */
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unsigned int best_bitrate_error = UINT_MAX;
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unsigned int sample_point_error; /* difference between current and nominal value */
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unsigned int best_sample_point_error = UINT_MAX;
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unsigned int sample_point_nominal; /* nominal sample point */
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unsigned int best_tseg = 0; /* current best value for tseg */
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unsigned int best_brp = 0; /* current best value for brp */
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unsigned int brp, tsegall, tseg, tseg1 = 0, tseg2 = 0;
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u64 v64;
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int err;
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/* Use CiA recommended sample points */
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if (bt->sample_point) {
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sample_point_nominal = bt->sample_point;
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} else {
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if (bt->bitrate > 800 * KILO /* BPS */)
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sample_point_nominal = 750;
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else if (bt->bitrate > 500 * KILO /* BPS */)
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sample_point_nominal = 800;
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else
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sample_point_nominal = 875;
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}
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/* tseg even = round down, odd = round up */
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for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
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tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
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tsegall = CAN_SYNC_SEG + tseg / 2;
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/* Compute all possible tseg choices (tseg=tseg1+tseg2) */
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brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
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/* choose brp step which is possible in system */
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brp = (brp / btc->brp_inc) * btc->brp_inc;
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if (brp < btc->brp_min || brp > btc->brp_max)
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continue;
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bitrate = priv->clock.freq / (brp * tsegall);
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bitrate_error = abs(bt->bitrate - bitrate);
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/* tseg brp biterror */
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if (bitrate_error > best_bitrate_error)
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continue;
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/* reset sample point error if we have a better bitrate */
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if (bitrate_error < best_bitrate_error)
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best_sample_point_error = UINT_MAX;
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can_update_sample_point(btc, sample_point_nominal, tseg / 2,
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&tseg1, &tseg2, &sample_point_error);
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if (sample_point_error >= best_sample_point_error)
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continue;
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best_sample_point_error = sample_point_error;
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best_bitrate_error = bitrate_error;
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best_tseg = tseg / 2;
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best_brp = brp;
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if (bitrate_error == 0 && sample_point_error == 0)
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break;
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}
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if (best_bitrate_error) {
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/* Error in one-tenth of a percent */
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v64 = (u64)best_bitrate_error * 1000;
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do_div(v64, bt->bitrate);
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bitrate_error = (u32)v64;
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if (bitrate_error > CAN_CALC_MAX_ERROR) {
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NL_SET_ERR_MSG_FMT(extack,
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"bitrate error: %u.%u%% too high",
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bitrate_error / 10, bitrate_error % 10);
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return -EINVAL;
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}
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NL_SET_ERR_MSG_FMT(extack,
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"bitrate error: %u.%u%%",
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bitrate_error / 10, bitrate_error % 10);
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}
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/* real sample point */
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bt->sample_point = can_update_sample_point(btc, sample_point_nominal,
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best_tseg, &tseg1, &tseg2,
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NULL);
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v64 = (u64)best_brp * 1000 * 1000 * 1000;
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do_div(v64, priv->clock.freq);
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bt->tq = (u32)v64;
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bt->prop_seg = tseg1 / 2;
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bt->phase_seg1 = tseg1 - bt->prop_seg;
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bt->phase_seg2 = tseg2;
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can_sjw_set_default(bt);
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err = can_sjw_check(dev, bt, btc, extack);
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if (err)
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return err;
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bt->brp = best_brp;
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/* real bitrate */
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bt->bitrate = priv->clock.freq /
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(bt->brp * can_bit_time(bt));
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return 0;
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}
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/* Checks the validity of the specified bit-timing parameters prop_seg,
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* phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
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* prescaler value brp. You can find more information in the header
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* file linux/can/netlink.h.
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*/
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static int can_fixup_bittiming(const struct net_device *dev, struct can_bittiming *bt,
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const struct can_bittiming_const *btc,
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struct netlink_ext_ack *extack)
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{
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const unsigned int tseg1 = bt->prop_seg + bt->phase_seg1;
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const struct can_priv *priv = netdev_priv(dev);
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u64 brp64;
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int err;
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if (tseg1 < btc->tseg1_min) {
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NL_SET_ERR_MSG_FMT(extack, "prop-seg + phase-seg1: %u less than tseg1-min: %u",
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tseg1, btc->tseg1_min);
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return -EINVAL;
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}
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if (tseg1 > btc->tseg1_max) {
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NL_SET_ERR_MSG_FMT(extack, "prop-seg + phase-seg1: %u greater than tseg1-max: %u",
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tseg1, btc->tseg1_max);
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return -EINVAL;
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}
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if (bt->phase_seg2 < btc->tseg2_min) {
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NL_SET_ERR_MSG_FMT(extack, "phase-seg2: %u less than tseg2-min: %u",
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bt->phase_seg2, btc->tseg2_min);
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return -EINVAL;
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}
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if (bt->phase_seg2 > btc->tseg2_max) {
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NL_SET_ERR_MSG_FMT(extack, "phase-seg2: %u greater than tseg2-max: %u",
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bt->phase_seg2, btc->tseg2_max);
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return -EINVAL;
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}
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can_sjw_set_default(bt);
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err = can_sjw_check(dev, bt, btc, extack);
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if (err)
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return err;
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brp64 = (u64)priv->clock.freq * (u64)bt->tq;
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if (btc->brp_inc > 1)
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do_div(brp64, btc->brp_inc);
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brp64 += 500000000UL - 1;
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do_div(brp64, 1000000000UL); /* the practicable BRP */
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if (btc->brp_inc > 1)
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brp64 *= btc->brp_inc;
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bt->brp = (u32)brp64;
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if (bt->brp < btc->brp_min) {
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NL_SET_ERR_MSG_FMT(extack, "resulting brp: %u less than brp-min: %u",
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bt->brp, btc->brp_min);
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return -EINVAL;
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}
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if (bt->brp > btc->brp_max) {
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NL_SET_ERR_MSG_FMT(extack, "resulting brp: %u greater than brp-max: %u",
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bt->brp, btc->brp_max);
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return -EINVAL;
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}
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bt->bitrate = priv->clock.freq / (bt->brp * can_bit_time(bt));
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bt->sample_point = ((CAN_SYNC_SEG + tseg1) * 1000) / can_bit_time(bt);
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bt->tq = DIV_U64_ROUND_CLOSEST(mul_u32_u32(bt->brp, NSEC_PER_SEC),
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priv->clock.freq);
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return 0;
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}
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@ -43,6 +43,12 @@ enum {
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/* imported from kernel */
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/* define in-kernel-types */
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typedef __u64 u64;
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typedef __u32 u32;
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#define NSEC_PER_SEC 1000000000L
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/**
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* abs - return absolute value of an argument
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* @x: the value. If it is unsigned type, it is converted to signed type first.
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@ -102,6 +108,48 @@ enum {
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__rem; \
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})
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/**
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* DIV_U64_ROUND_CLOSEST - unsigned 64bit divide with 32bit divisor rounded to nearest integer
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* @dividend: unsigned 64bit dividend
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* @divisor: unsigned 32bit divisor
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*
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* Divide unsigned 64bit dividend by unsigned 32bit divisor
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* and round to closest integer.
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*
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* Return: dividend / divisor rounded to nearest integer
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*/
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#define DIV_U64_ROUND_CLOSEST(dividend, divisor) \
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({ u32 _tmp = (divisor); div_u64((u64)(dividend) + _tmp / 2, _tmp); })
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/**
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* div_u64_rem - unsigned 64bit divide with 32bit divisor with remainder
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* @dividend: unsigned 64bit dividend
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* @divisor: unsigned 32bit divisor
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* @remainder: pointer to unsigned 32bit remainder
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*
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* Return: sets ``*remainder``, then returns dividend / divisor
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*
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* This is commonly provided by 32bit archs to provide an optimized 64bit
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* divide.
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*/
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static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
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{
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*remainder = dividend % divisor;
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return dividend / divisor;
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}
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static inline u64 div_u64(u64 dividend, u32 divisor)
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{
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u32 remainder;
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return div_u64_rem(dividend, divisor, &remainder);
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}
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static inline u64 mul_u32_u32(u32 a, u32 b)
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{
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return (u64)a * b;
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}
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/* */
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#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
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@ -109,10 +157,7 @@ enum {
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/* we don't want to see these prints */
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#define netdev_err(dev, format, arg...) do { } while (0)
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#define netdev_warn(dev, format, arg...) do { } while (0)
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/* define in-kernel-types */
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typedef __u64 u64;
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typedef __u32 u32;
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#define NL_SET_ERR_MSG_FMT(dev, format, arg...) do { } while (0)
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struct calc_ref_clk {
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__u32 clk; /* CAN system clock frequency in Hz */
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@ -130,6 +175,10 @@ struct net_device {
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struct can_priv priv;
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};
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struct netlink_ext_ack {
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u32 __dummy;
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};
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struct calc_bittiming_const {
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const struct can_bittiming_const bittiming_const;
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const struct can_bittiming_const data_bittiming_const;
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@ -146,12 +195,18 @@ struct alg {
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const struct can_bittiming_const *btc);
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int (*calc_bittiming_const)(const struct net_device *dev, struct can_bittiming *bt,
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const struct can_bittiming_const *btc);
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int (*calc_bittiming_extack)(const struct net_device *dev, struct can_bittiming *bt,
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const struct can_bittiming_const *btc, struct netlink_ext_ack *extack);
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};
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union {
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int (*fixup_bittiming)(struct net_device *dev, struct can_bittiming *bt,
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const struct can_bittiming_const *btc);
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int (*fixup_bittiming_const)(const struct net_device *dev, struct can_bittiming *bt,
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const struct can_bittiming_const *btc);
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int (*fixup_bittiming_extack)(const struct net_device *dev, struct can_bittiming *bt,
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const struct can_bittiming_const *btc,
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struct netlink_ext_ack *extack);
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};
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const char *name;
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};
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@ -1232,9 +1287,21 @@ static const unsigned int common_data_bitrates[] = {
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#undef can_calc_bittiming
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#undef can_fixup_bittiming
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#define can_update_sample_point can_update_sample_point_v6_3
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#define can_calc_bittiming can_calc_bittiming_v6_3
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#define can_fixup_bittiming can_fixup_bittiming_v6_3
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#include "can-calc-bit-timing-v6_3.c"
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#undef can_update_sample_point
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#undef can_calc_bittiming
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#undef can_fixup_bittiming
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static const struct alg alg_list[] = {
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/* 1st will be default */
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{
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.calc_bittiming_extack = can_calc_bittiming_v6_3,
|
||||
.fixup_bittiming_extack = can_fixup_bittiming_v6_3,
|
||||
.name = "v6.3",
|
||||
}, {
|
||||
.calc_bittiming_const = can_calc_bittiming_v5_19,
|
||||
.fixup_bittiming_const = can_fixup_bittiming_v5_19,
|
||||
.name = "v5.19",
|
||||
|
|
|
|||
Loading…
Reference in New Issue