* This software is released under the GPL-License.
*/
+#include <errno.h>
+#include <getopt.h>
+#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
-#include <stdint.h>
#include <string.h>
-#include <getopt.h>
+
+#include <linux/types.h>
+
+/* seems not to be defined in errno.h */
+#ifndef ENOTSUPP
+#define ENOTSUPP 524 /* Operation is not supported */
+#endif
+
+/* usefull 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 */
+ 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"
exit(1);
}
-struct can_bittime {
- uint32_t brp;
- uint8_t prop_seg;
- uint8_t phase_seg1;
- uint8_t phase_seg2;
- uint8_t sjw;
- uint32_t tq;
- uint32_t error;
- int sampl_pt;
-};
-
-struct can_bittiming_const {
- char name[32];
- int prop_seg_min;
- int prop_seg_max;
- int phase_seg1_min;
- int phase_seg1_max;
- int phase_seg2_min;
- int phase_seg2_max;
- int sjw_max;
- int brp_min;
- int brp_max;
- int brp_inc;
- void (*printf_btr)(struct can_bittime *bt, int hdr);
-};
-
-static void printf_btr_sja1000(struct can_bittime *bt, int hdr)
+static void printf_btr_sja1000(struct can_bittiming *bt, int hdr)
{
uint8_t btr0, btr1;
}
}
-static void printf_btr_at91(struct can_bittime *bt, int hdr)
+static void printf_btr_at91(struct can_bittiming *bt, int hdr)
{
if (hdr) {
printf("CAN_BR");
}
}
-static void printf_btr_mcp2510(struct can_bittime *bt, int hdr)
+static void printf_btr_mcp251x(struct can_bittiming *bt, int hdr)
{
uint8_t cnf1, cnf2, cnf3;
}
}
-static void printf_btr_rtcantl1(struct can_bittime *bt, int hdr)
+static void printf_btr_rtcantl1(struct can_bittiming *bt, int hdr)
{
uint16_t bcr0, bcr1;
}
}
-struct can_bittiming_const can_calc_consts[] = {
+static struct can_bittiming_const can_calc_consts[] = {
{
- "sja1000",
- /* Note: only prop_seg + bt->phase_seg1 matters */
- .phase_seg1_min = 1,
- .phase_seg1_max = 16,
- .phase_seg2_min = 1,
- .phase_seg2_max = 8,
+ .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,
+
.printf_btr = printf_btr_sja1000,
},
{
- "mscan",
- /* Note: only prop_seg + bt->phase_seg1 matters */
- .phase_seg1_min = 4,
- .phase_seg1_max = 16,
- .phase_seg2_min = 2,
- .phase_seg2_max = 8,
+ .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,
+
.printf_btr = printf_btr_sja1000,
},
{
- "at91",
- .prop_seg_min = 1,
- .prop_seg_max = 8,
- .phase_seg1_min = 1,
- .phase_seg1_max = 8,
- .phase_seg2_min = 2,
- .phase_seg2_max = 8,
+ .name = "at91",
+ .tseg1_min = 4,
+ .tseg1_max = 16,
+ .tseg2_min = 2,
+ .tseg2_max = 8,
.sjw_max = 4,
- .brp_min = 1,
+ .brp_min = 2,
.brp_max = 128,
.brp_inc = 1,
+
.printf_btr = printf_btr_at91,
},
{
- "mcp2510",
- .prop_seg_min = 1,
- .prop_seg_max = 8,
- .phase_seg1_min = 1,
- .phase_seg1_max = 8,
- .phase_seg2_min = 2,
- .phase_seg2_max = 8,
+ .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,
- .printf_btr = printf_btr_mcp2510,
+
+ .printf_btr = printf_btr_mcp251x,
},
{
- "rtcantl1",
- .prop_seg_min = 2,
- .prop_seg_max = 8,
- .phase_seg1_min = 2,
- .phase_seg1_max = 8,
- .phase_seg2_min = 2,
- .phase_seg2_max = 8,
+ .name = "rtcantl1",
+ .tseg1_min = 4,
+ .tseg1_max = 16,
+ .tseg2_min = 2,
+ .tseg2_max = 8,
.sjw_max = 4,
.brp_min = 1,
.brp_max = 256,
.brp_inc = 1,
+
.printf_btr = printf_btr_rtcantl1,
},
};
100000,
50000,
20000,
- 10000
+ 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->phase_seg2_min)
- *tseg2 = btc->phase_seg2_min;
- if (*tseg2 > btc->phase_seg2_max)
- *tseg2 = btc->phase_seg2_max;
+ if (*tseg2 < btc->tseg2_min)
+ *tseg2 = btc->tseg2_min;
+ if (*tseg2 > btc->tseg2_max)
+ *tseg2 = btc->tseg2_max;
*tseg1 = tseg - *tseg2;
- if (*tseg1 > btc->prop_seg_max + btc->phase_seg1_max) {
- *tseg1 = btc->prop_seg_max + btc->phase_seg1_max;
+ if (*tseg1 > btc->tseg1_max) {
+ *tseg1 = btc->tseg1_max;
*tseg2 = tseg - *tseg1;
}
return 1000 * (tseg + 1 - *tseg2) / (tseg + 1);
}
-int can_calc_bittiming(struct can_bittime *bt, long bitrate,
- int sampl_pt, long clock,
- const struct can_bittiming_const *btc)
+static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt)
{
- long best_error = 1000000000, error;
- int best_tseg = 0, best_brp = 0, brp = 0;
- int spt_error = 1000, spt = 0;
+ struct can_priv *priv = netdev_priv(dev);
+ const struct can_bittiming_const *btc = priv->bittiming_const;
long rate, best_rate = 0;
- int tseg = 0, tseg1 = 0, tseg2 = 0;
- uint64_t v64;
+ 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;
- if (sampl_pt == 0) {
- /* Use CIA recommended sample points */
- if (bitrate > 800000)
+ /* Use CIA recommended sample points */
+ if (bt->sample_point) {
+ sampl_pt = bt->sample_point;
+ } else {
+ if (bt->bitrate > 800000)
sampl_pt = 750;
- else if (bitrate > 500000)
+ else if (bt->bitrate > 500000)
sampl_pt = 800;
else
sampl_pt = 875;
}
-#ifdef DEBUG
- printf("tseg brp bitrate biterror\n");
-#endif
-
/* tseg even = round down, odd = round up */
- for (tseg = (btc->prop_seg_max + btc->phase_seg1_max +
- btc->phase_seg2_max) * 2 + 1;
- tseg >= (btc->prop_seg_min + btc->phase_seg1_min +
- btc->phase_seg2_min) * 2; tseg--) {
- /* Compute all posibilities of tseg choices (tseg=tseg1+tseg2) */
- brp = clock / ((1 + tseg / 2) * bitrate) + tseg % 2;
+ 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 = clock / (brp * (1 + tseg / 2));
- error = bitrate - rate;
+ rate = priv->clock.freq / (brp * tsegall);
+ error = bt->bitrate - rate;
/* tseg brp biterror */
-#if DEBUG
- printf("%4d %3d %7ld %8ld %03d\n", tseg, brp, rate, error,
- can_update_spt(btc, sampl_pt, tseg / 2,
- &tseg1, &tseg2));
-#endif
if (error < 0)
error = -error;
if (error > best_error)
spt = can_update_spt(btc, sampl_pt, tseg / 2,
&tseg1, &tseg2);
error = sampl_pt - spt;
- //printf("%d %d %d\n", sampl_pt, error, spt_error);
if (error < 0)
error = -error;
if (error > spt_error)
continue;
spt_error = error;
- //printf("%d\n", spt_error);
}
- //printf("error=%d\n", best_error);
best_tseg = tseg / 2;
best_brp = brp;
best_rate = rate;
break;
}
- if (best_error && (bitrate / best_error < 10))
- return -1;
+ 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);
+ }
+ }
- spt = can_update_spt(btc, sampl_pt, best_tseg,
- &tseg1, &tseg2);
+ /* real sample point */
+ bt->sample_point = can_update_spt(btc, sampl_pt, best_tseg,
+ &tseg1, &tseg2);
- if (tseg2 > tseg1) {
- /* sample point < 50% */
- bt->phase_seg1 = tseg1 / 2;
- } else {
- /* keep phase_seg{1,2} equal around the sample point */
- bt->phase_seg1 = tseg2;
- }
- bt->prop_seg = tseg1 - bt->phase_seg1;
- /* Check prop_seg range if necessary */
- if (btc->prop_seg_min || btc->prop_seg_max) {
- if (bt->prop_seg < btc->prop_seg_min)
- bt->prop_seg = btc->prop_seg_min;
- else if (bt->prop_seg > btc->prop_seg_max)
- bt->prop_seg = btc->prop_seg_max;
- bt->phase_seg1 = tseg1 - bt->prop_seg;
- }
+ 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;
- bt->error = best_error;
- bt->sampl_pt = spt;
- v64 = (uint64_t)bt->brp * 1000000000UL;
- v64 /= clock;
- bt->tq = (int)v64;
+
+ /* real bit-rate */
+ bt->bitrate = priv->clock.freq / (bt->brp * (tseg1 + tseg2 + 1));
return 0;
}
-void print_bit_timing(const struct can_bittiming_const *btc,
- long bitrate, int sampl_pt, long ref_clk, int quiet)
+static void print_bit_timing(const struct can_bittiming_const *btc,
+ __u32 bitrate, __u32 sample_point, __u32 ref_clk,
+ int quiet)
{
- struct can_bittime bt;
-
- memset(&bt, 0, sizeof(bt));
+ 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;
if (!quiet) {
- printf("Bit timing parameters for %s using %ldHz\n",
+ printf("Bit timing parameters for %s using %dHz\n",
btc->name, ref_clk);
printf("Bitrate TQ[ns] PrS PhS1 PhS2 SJW BRP SampP Error ");
btc->printf_btr(&bt, 1);
printf("\n");
}
- if (can_calc_bittiming(&bt, bitrate, sampl_pt, ref_clk, btc)) {
- printf("%7ld ***bitrate not possible***\n", bitrate);
+ if (can_calc_bittiming(&dev, &bt)) {
+ printf("%7d ***bitrate not possible***\n", bitrate);
return;
}
- printf("%7ld %6d %3d %4d %4d %3d %3d %2d.%d%% %4.1f%% ",
+ rate_error = abs((__s32)(bitrate - bt.bitrate));
+
+ printf("%7d %6d %3d %4d %4d %3d %3d %2d.%d%% %4.1f%% ",
bitrate, bt.tq, bt.prop_seg, bt.phase_seg1,
bt.phase_seg2, bt.sjw, bt.brp,
- bt.sampl_pt / 10, bt.sampl_pt % 10,
- (double)100 * bt.error / bitrate);
+ bt.sample_point / 10, bt.sample_point % 10,
+ 100.0 * rate_error / bitrate);
btc->printf_btr(&bt, 0);
printf("\n");
}
projects / socketcan-devel.git / commitdiff