android13/external/can-utils/can-calc-bit-timing.c

723 lines
15 KiB
C
Executable File

/* can-calc-bit-timing.c: Calculate CAN bit timing parameters
*
* Copyright (C) 2008 Wolfgang Grandegger <wg@grandegger.com>
*
* Derived from:
* can_baud.c - CAN baudrate calculation
* 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
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* any later version.
*/
#include <errno.h>
#include <getopt.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <linux/types.h>
/* seems not to be defined in errno.h */
#ifndef ENOTSUPP
#define ENOTSUPP 524 /* Operation is not supported */
#endif
/* useful defines */
#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
#define do_div(a,b) a = (a) / (b)
#define abs(x) ({ \
long __x = (x); \
(__x < 0) ? -__x : __x; \
})
/**
* clamp - return a value clamped to a given range with strict typechecking
* @val: current value
* @min: minimum allowable value
* @max: maximum allowable value
*
* This macro does strict typechecking of min/max to make sure they are of the
* same type as val. See the unnecessary pointer comparisons.
*/
#define clamp(val, min, max) ({ \
typeof(val) __val = (val); \
typeof(min) __min = (min); \
typeof(max) __max = (max); \
(void) (&__val == &__min); \
(void) (&__val == &__max); \
__val = __val < __min ? __min: __val; \
__val > __max ? __max: __val; })
/* we don't want to see these prints */
#define dev_err(dev, format, arg...) do { } while (0)
#define dev_warn(dev, format, arg...) do { } while (0)
/* define in-kernel-types */
typedef __u64 u64;
typedef __u32 u32;
/*
* CAN bit-timing parameters
*
* For futher information, please read chapter "8 BIT TIMING
* REQUIREMENTS" of the "Bosch CAN Specification version 2.0"
* at http://www.semiconductors.bosch.de/pdf/can2spec.pdf.
*/
struct can_bittiming {
__u32 bitrate; /* Bit-rate in bits/second */
__u32 sample_point; /* Sample point in one-tenth of a percent */
__u32 tq; /* Time quanta (TQ) in nanoseconds */
__u32 prop_seg; /* Propagation segment in TQs */
__u32 phase_seg1; /* Phase buffer segment 1 in TQs */
__u32 phase_seg2; /* Phase buffer segment 2 in TQs */
__u32 sjw; /* Synchronisation jump width in TQs */
__u32 brp; /* Bit-rate prescaler */
};
/*
* CAN harware-dependent bit-timing constant
*
* Used for calculating and checking bit-timing parameters
*/
struct can_bittiming_const {
char name[16]; /* Name of the CAN controller hardware */
__u32 tseg1_min; /* Time segement 1 = prop_seg + phase_seg1 */
__u32 tseg1_max;
__u32 tseg2_min; /* Time segement 2 = phase_seg2 */
__u32 tseg2_max;
__u32 sjw_max; /* Synchronisation jump width */
__u32 brp_min; /* Bit-rate prescaler */
__u32 brp_max;
__u32 brp_inc;
/* added for can-calc-bit-timing utility */
__u32 ref_clk; /* CAN system clock frequency in Hz */
void (*printf_btr)(struct can_bittiming *bt, int hdr);
};
/*
* CAN clock parameters
*/
struct can_clock {
__u32 freq; /* CAN system clock frequency in Hz */
};
/*
* minimal structs, just enough to be source level compatible
*/
struct can_priv {
const struct can_bittiming_const *bittiming_const;
struct can_clock clock;
};
struct net_device {
struct can_priv priv;
};
static inline void *netdev_priv(const struct net_device *dev)
{
return (void *)&dev->priv;
}
static void print_usage(char* cmd)
{
printf("Usage: %s [options] [<CAN-contoller-name>]\n"
"\tOptions:\n"
"\t-q : don't print header line\n"
"\t-l : list all support CAN controller names\n"
"\t-b <bitrate> : bit-rate in bits/sec\n"
"\t-s <samp_pt> : sample-point in one-tenth of a percent\n"
"\t or 0 for CIA recommended sample points\n"
"\t-c <clock> : real CAN system clock in Hz\n",
cmd);
exit(EXIT_FAILURE);
}
static void printf_btr_sja1000(struct can_bittiming *bt, int hdr)
{
uint8_t btr0, btr1;
if (hdr) {
printf("BTR0 BTR1");
} else {
btr0 = ((bt->brp - 1) & 0x3f) | (((bt->sjw - 1) & 0x3) << 6);
btr1 = ((bt->prop_seg + bt->phase_seg1 - 1) & 0xf) |
(((bt->phase_seg2 - 1) & 0x7) << 4);
printf("0x%02x 0x%02x", btr0, btr1);
}
}
static void printf_btr_at91(struct can_bittiming *bt, int hdr)
{
if (hdr) {
printf("%10s", "CAN_BR");
} else {
uint32_t br = ((bt->phase_seg2 - 1) |
((bt->phase_seg1 - 1) << 4) |
((bt->prop_seg - 1) << 8) |
((bt->sjw - 1) << 12) |
((bt->brp - 1) << 16));
printf("0x%08x", br);
}
}
static void printf_btr_flexcan(struct can_bittiming *bt, int hdr)
{
if (hdr) {
printf("%10s", "CAN_CTRL");
} else {
uint32_t ctrl = (((bt->brp - 1) << 24) |
((bt->sjw - 1) << 22) |
((bt->phase_seg1 - 1) << 19) |
((bt->phase_seg2 - 1) << 16) |
((bt->prop_seg - 1) << 0));
printf("0x%08x", ctrl);
}
}
static void printf_btr_mcp251x(struct can_bittiming *bt, int hdr)
{
uint8_t cnf1, cnf2, cnf3;
if (hdr) {
printf("CNF1 CNF2 CNF3");
} else {
cnf1 = ((bt->sjw - 1) << 6) | (bt->brp - 1);
cnf2 = 0x80 | ((bt->phase_seg1 - 1) << 3) | (bt->prop_seg - 1);
cnf3 = bt->phase_seg2 - 1;
printf("0x%02x 0x%02x 0x%02x", cnf1, cnf2, cnf3);
}
}
static void printf_btr_ti_hecc(struct can_bittiming *bt, int hdr)
{
if (hdr) {
printf("%10s", "CANBTC");
} else {
uint32_t can_btc;
can_btc = (bt->phase_seg2 - 1) & 0x7;
can_btc |= ((bt->phase_seg1 + bt->prop_seg - 1)
& 0xF) << 3;
can_btc |= ((bt->sjw - 1) & 0x3) << 8;
can_btc |= ((bt->brp - 1) & 0xFF) << 16;
printf("0x%08x", can_btc);
}
}
static struct can_bittiming_const can_calc_consts[] = {
{
.name = "sja1000",
.tseg1_min = 1,
.tseg1_max = 16,
.tseg2_min = 1,
.tseg2_max = 8,
.sjw_max = 4,
.brp_min = 1,
.brp_max = 64,
.brp_inc = 1,
.ref_clk = 8000000,
.printf_btr = printf_btr_sja1000,
},
{
.name = "mscan",
.tseg1_min = 4,
.tseg1_max = 16,
.tseg2_min = 2,
.tseg2_max = 8,
.sjw_max = 4,
.brp_min = 1,
.brp_max = 64,
.brp_inc = 1,
.ref_clk = 32000000,
.printf_btr = printf_btr_sja1000,
},
{
.name = "mscan",
.tseg1_min = 4,
.tseg1_max = 16,
.tseg2_min = 2,
.tseg2_max = 8,
.sjw_max = 4,
.brp_min = 1,
.brp_max = 64,
.brp_inc = 1,
.ref_clk = 33000000,
.printf_btr = printf_btr_sja1000,
},
{
.name = "mscan",
.tseg1_min = 4,
.tseg1_max = 16,
.tseg2_min = 2,
.tseg2_max = 8,
.sjw_max = 4,
.brp_min = 1,
.brp_max = 64,
.brp_inc = 1,
.ref_clk = 33300000,
.printf_btr = printf_btr_sja1000,
},
{
.name = "mscan",
.tseg1_min = 4,
.tseg1_max = 16,
.tseg2_min = 2,
.tseg2_max = 8,
.sjw_max = 4,
.brp_min = 1,
.brp_max = 64,
.brp_inc = 1,
.ref_clk = 33333333,
.printf_btr = printf_btr_sja1000,
},
{
.name = "mscan",
.tseg1_min = 4,
.tseg1_max = 16,
.tseg2_min = 2,
.tseg2_max = 8,
.sjw_max = 4,
.brp_min = 1,
.brp_max = 64,
.brp_inc = 1,
.ref_clk = 66660000, /* mpc5121 */
.printf_btr = printf_btr_sja1000,
},
{
.name = "at91",
.tseg1_min = 4,
.tseg1_max = 16,
.tseg2_min = 2,
.tseg2_max = 8,
.sjw_max = 4,
.brp_min = 2,
.brp_max = 128,
.brp_inc = 1,
.ref_clk = 100000000,
.printf_btr = printf_btr_at91,
},
{
.name = "at91",
.tseg1_min = 4,
.tseg1_max = 16,
.tseg2_min = 2,
.tseg2_max = 8,
.sjw_max = 4,
.brp_min = 2,
.brp_max = 128,
.brp_inc = 1,
/* real world clock as found on the ronetix PM9263 */
.ref_clk = 99532800,
.printf_btr = printf_btr_at91,
},
{
.name = "flexcan",
.tseg1_min = 4,
.tseg1_max = 16,
.tseg2_min = 2,
.tseg2_max = 8,
.sjw_max = 4,
.brp_min = 1,
.brp_max = 256,
.brp_inc = 1,
.ref_clk = 24000000, /* mx28 */
.printf_btr = printf_btr_flexcan,
},
{
.name = "flexcan",
.tseg1_min = 4,
.tseg1_max = 16,
.tseg2_min = 2,
.tseg2_max = 8,
.sjw_max = 4,
.brp_min = 1,
.brp_max = 256,
.brp_inc = 1,
.ref_clk = 49875000,
.printf_btr = printf_btr_flexcan,
},
{
.name = "flexcan",
.tseg1_min = 4,
.tseg1_max = 16,
.tseg2_min = 2,
.tseg2_max = 8,
.sjw_max = 4,
.brp_min = 1,
.brp_max = 256,
.brp_inc = 1,
.ref_clk = 66000000,
.printf_btr = printf_btr_flexcan,
},
{
.name = "flexcan",
.tseg1_min = 4,
.tseg1_max = 16,
.tseg2_min = 2,
.tseg2_max = 8,
.sjw_max = 4,
.brp_min = 1,
.brp_max = 256,
.brp_inc = 1,
.ref_clk = 66500000,
.printf_btr = printf_btr_flexcan,
},
{
.name = "mcp251x",
.tseg1_min = 3,
.tseg1_max = 16,
.tseg2_min = 2,
.tseg2_max = 8,
.sjw_max = 4,
.brp_min = 1,
.brp_max = 64,
.brp_inc = 1,
.ref_clk = 8000000,
.printf_btr = printf_btr_mcp251x,
},
{
.name = "mcp251x",
.tseg1_min = 3,
.tseg1_max = 16,
.tseg2_min = 2,
.tseg2_max = 8,
.sjw_max = 4,
.brp_min = 1,
.brp_max = 64,
.brp_inc = 1,
.ref_clk = 16000000,
.printf_btr = printf_btr_mcp251x,
},
{
.name = "ti_hecc",
.tseg1_min = 1,
.tseg1_max = 16,
.tseg2_min = 1,
.tseg2_max = 8,
.sjw_max = 4,
.brp_min = 1,
.brp_max = 256,
.brp_inc = 1,
.ref_clk = 13000000,
.printf_btr = printf_btr_ti_hecc,
}
};
static long common_bitrates[] = {
1000000,
800000,
500000,
250000,
125000,
100000,
50000,
20000,
10000,
};
#define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */
static int can_update_spt(const struct can_bittiming_const *btc,
int sampl_pt, int tseg, int *tseg1, int *tseg2)
{
*tseg2 = tseg + 1 - (sampl_pt * (tseg + 1)) / 1000;
if (*tseg2 < btc->tseg2_min)
*tseg2 = btc->tseg2_min;
if (*tseg2 > btc->tseg2_max)
*tseg2 = btc->tseg2_max;
*tseg1 = tseg - *tseg2;
if (*tseg1 > btc->tseg1_max) {
*tseg1 = btc->tseg1_max;
*tseg2 = tseg - *tseg1;
}
return 1000 * (tseg + 1 - *tseg2) / (tseg + 1);
}
static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt)
{
struct can_priv *priv = netdev_priv(dev);
const struct can_bittiming_const *btc = priv->bittiming_const;
long rate = 0;
long best_error = 1000000000, error = 0;
int best_tseg = 0, best_brp = 0, brp = 0;
int tsegall, tseg = 0, tseg1 = 0, tseg2 = 0;
int spt_error = 1000, spt = 0, sampl_pt;
u64 v64;
if (!priv->bittiming_const)
return -ENOTSUPP;
/* Use CIA recommended sample points */
if (bt->sample_point) {
sampl_pt = bt->sample_point;
} else {
if (bt->bitrate > 800000)
sampl_pt = 750;
else if (bt->bitrate > 500000)
sampl_pt = 800;
else
sampl_pt = 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 = 1 + tseg / 2;
/* Compute all possible tseg choices (tseg=tseg1+tseg2) */
brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
/* chose 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;
rate = priv->clock.freq / (brp * tsegall);
error = bt->bitrate - rate;
/* tseg brp biterror */
if (error < 0)
error = -error;
if (error > best_error)
continue;
best_error = error;
if (error == 0) {
spt = can_update_spt(btc, sampl_pt, tseg / 2,
&tseg1, &tseg2);
error = sampl_pt - spt;
if (error < 0)
error = -error;
if (error > spt_error)
continue;
spt_error = error;
}
best_tseg = tseg / 2;
best_brp = brp;
if (error == 0)
break;
}
if (best_error) {
/* Error in one-tenth of a percent */
error = (best_error * 1000) / bt->bitrate;
if (error > CAN_CALC_MAX_ERROR) {
dev_err(dev->dev.parent,
"bitrate error %ld.%ld%% too high\n",
error / 10, error % 10);
return -EDOM;
} else {
dev_warn(dev->dev.parent, "bitrate error %ld.%ld%%\n",
error / 10, error % 10);
}
}
/* real sample point */
bt->sample_point = can_update_spt(btc, sampl_pt, best_tseg,
&tseg1, &tseg2);
v64 = (u64)best_brp * 1000000000UL;
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;
bt->sjw = 1;
bt->brp = best_brp;
/* real bit-rate */
bt->bitrate = priv->clock.freq / (bt->brp * (tseg1 + tseg2 + 1));
return 0;
}
static __u32 get_cia_sample_point(__u32 bitrate)
{
__u32 sampl_pt;
if (bitrate > 800000)
sampl_pt = 750;
else if (bitrate > 500000)
sampl_pt = 800;
else
sampl_pt = 875;
return sampl_pt;
}
static void print_bit_timing(const struct can_bittiming_const *btc,
__u32 bitrate, __u32 sample_point, __u32 ref_clk,
int quiet)
{
struct net_device dev = {
.priv.bittiming_const = btc,
.priv.clock.freq = ref_clk,
};
struct can_bittiming bt = {
.bitrate = bitrate,
.sample_point = sample_point,
};
long rate_error, spt_error;
if (!quiet) {
printf("Bit timing parameters for %s with %.6f MHz ref clock\n"
"nominal real Bitrt nom real SampP\n"
"Bitrate TQ[ns] PrS PhS1 PhS2 SJW BRP Bitrate Error SampP SampP Error ",
btc->name,
ref_clk / 1000000.0);
btc->printf_btr(&bt, 1);
printf("\n");
}
if (can_calc_bittiming(&dev, &bt)) {
printf("%7d ***bitrate not possible***\n", bitrate);
return;
}
/* get nominal sample point */
if (!sample_point)
sample_point = get_cia_sample_point(bitrate);
rate_error = abs((__s32)(bitrate - bt.bitrate));
spt_error = abs((__s32)(sample_point - bt.sample_point));
printf("%7d "
"%6d %3d %4d %4d "
"%3d %3d "
"%7d %4.1f%% "
"%4.1f%% %4.1f%% %4.1f%% ",
bitrate,
bt.tq, bt.prop_seg, bt.phase_seg1, bt.phase_seg2,
bt.sjw, bt.brp,
bt.bitrate,
100.0 * rate_error / bitrate,
sample_point / 10.0,
bt.sample_point / 10.0,
100.0 * spt_error / sample_point);
btc->printf_btr(&bt, 0);
printf("\n");
}
static void do_list(void)
{
unsigned int i;
for (i = 0; i < ARRAY_SIZE(can_calc_consts); i++)
printf("%s\n", can_calc_consts[i].name);
}
int main(int argc, char *argv[])
{
__u32 bitrate = 0;
__u32 opt_ref_clk = 0, ref_clk;
int sampl_pt = 0;
int quiet = 0;
int list = 0;
char *name = NULL;
unsigned int i, j;
int opt, found = 0;
const struct can_bittiming_const *btc = NULL;
while ((opt = getopt(argc, argv, "b:c:lps:")) != -1) {
switch (opt) {
case 'b':
bitrate = atoi(optarg);
break;
case 'c':
opt_ref_clk = atoi(optarg);
break;
case 'l':
list = 1;
break;
case 'q':
quiet = 1;
break;
case 's':
sampl_pt = atoi(optarg);
break;
default:
print_usage(argv[0]);
break;
}
}
if (argc > optind + 1)
print_usage(argv[0]);
if (argc == optind + 1)
name = argv[optind];
if (list) {
do_list();
exit(EXIT_SUCCESS);
}
if (sampl_pt && (sampl_pt >= 1000 || sampl_pt < 100))
print_usage(argv[0]);
for (i = 0; i < ARRAY_SIZE(can_calc_consts); i++) {
if (name && strcmp(can_calc_consts[i].name, name))
continue;
found = 1;
btc = &can_calc_consts[i];
if (opt_ref_clk)
ref_clk = opt_ref_clk;
else
ref_clk = btc->ref_clk;
if (bitrate) {
print_bit_timing(btc, bitrate, sampl_pt, ref_clk, quiet);
} else {
for (j = 0; j < ARRAY_SIZE(common_bitrates); j++)
print_bit_timing(btc, common_bitrates[j],
sampl_pt, ref_clk, j);
}
printf("\n");
}
if (!found) {
printf("error: unknown CAN controller '%s', try one of these:\n\n", name);
do_list();
exit(EXIT_FAILURE);
}
exit(EXIT_SUCCESS);
}