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Commit 5a9d5ecd authored by Marc Kleine-Budde's avatar Marc Kleine-Budde
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can: dev: move bittiming related code into seperate file 

This patch moves the bittiming related code of the CAN device infrastructure
into a separate file.
Reviewed-by: default avatarVincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://lore.kernel.org/r/20210111141930.693847-4-mkl@pengutronix.deSigned-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 3e77f70e
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MAINTAINERS
View file @ 5a9d5ecd
...@@ -3943,6 +3943,7 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can.git ...@@ -3943,6 +3943,7 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can.git
T: git git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can-next.git T: git git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can-next.git
F: Documentation/devicetree/bindings/net/can/ F: Documentation/devicetree/bindings/net/can/
F: drivers/net/can/ F: drivers/net/can/
F: include/linux/can/bittiming.h
F: include/linux/can/dev.h F: include/linux/can/dev.h
F: include/linux/can/led.h F: include/linux/can/led.h
F: include/linux/can/platform/ F: include/linux/can/platform/
......
drivers/net/can/dev/Makefile
View file @ 5a9d5ecd
# SPDX-License-Identifier: GPL-2.0 # SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_CAN_DEV) += can-dev.o obj-$(CONFIG_CAN_DEV) += can-dev.o
can-dev-y += bittiming.o
can-dev-y += dev.o can-dev-y += dev.o
can-dev-y += rx-offload.o can-dev-y += rx-offload.o
......
drivers/net/can/dev/bittiming.c 0 → 100644
View file @ 5a9d5ecd
// 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 <wg@grandegger.com>
*/
#include <linux/can/dev.h>
#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;
}
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;
}
#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;
}
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;
}
drivers/net/can/dev/dev.c
View file @ 5a9d5ecd
...@@ -58,267 +58,6 @@ u8 can_fd_len2dlc(u8 len) ...@@ -58,267 +58,6 @@ u8 can_fd_len2dlc(u8 len)
} }
EXPORT_SYMBOL_GPL(can_fd_len2dlc); 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, static void can_update_state_error_stats(struct net_device *dev,
enum can_state new_state) enum can_state new_state)
{ {
......
include/linux/can/bittiming.h 0 → 100644
View file @ 5a9d5ecd
/* SPDX-License-Identifier: GPL-2.0-only */
/* Copyright (c) 2020 Pengutronix, Marc Kleine-Budde <kernel@pengutronix.de>
*/
#ifndef _CAN_BITTIMING_H
#define _CAN_BITTIMING_H
#include <linux/netdevice.h>
#include <linux/can/netlink.h>
#define CAN_SYNC_SEG 1
#ifdef CONFIG_CAN_CALC_BITTIMING
int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
const struct can_bittiming_const *btc);
#else /* !CONFIG_CAN_CALC_BITTIMING */
static inline 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 */
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);
/*
* can_bit_time() - Duration of one bit
*
* Please refer to ISO 11898-1:2015, section 11.3.1.1 "Bit time" for
* additional information.
*
* Return: the number of time quanta in one bit.
*/
static inline unsigned int can_bit_time(const struct can_bittiming *bt)
{
return CAN_SYNC_SEG + bt->prop_seg + bt->phase_seg1 + bt->phase_seg2;
}
#endif /* !_CAN_BITTIMING_H */
include/linux/can/dev.h
View file @ 5a9d5ecd
...@@ -15,6 +15,7 @@ ...@@ -15,6 +15,7 @@
#define _CAN_DEV_H #define _CAN_DEV_H
#include <linux/can.h> #include <linux/can.h>
#include <linux/can/bittiming.h>
#include <linux/can/error.h> #include <linux/can/error.h>
#include <linux/can/led.h> #include <linux/can/led.h>
#include <linux/can/netlink.h> #include <linux/can/netlink.h>
...@@ -82,21 +83,6 @@ struct can_priv { ...@@ -82,21 +83,6 @@ struct can_priv {
#endif #endif
}; };
#define CAN_SYNC_SEG 1
/*
* can_bit_time() - Duration of one bit
*
* Please refer to ISO 11898-1:2015, section 11.3.1.1 "Bit time" for
* additional information.
*
* Return: the number of time quanta in one bit.
*/
static inline unsigned int can_bit_time(const struct can_bittiming *bt)
{
return CAN_SYNC_SEG + bt->prop_seg + bt->phase_seg1 + bt->phase_seg2;
}
/* /*
* can_cc_dlc2len(value) - convert a given data length code (dlc) of a * can_cc_dlc2len(value) - convert a given data length code (dlc) of a
* Classical CAN frame into a valid data length of max. 8 bytes. * Classical CAN frame into a valid data length of max. 8 bytes.
......
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