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leon,grcan: use common CAN baud-rate calculation routine

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Update #4323.
This commit is contained in:
Daniel Hellstrom
2021-03-11 17:31:21 +01:00
parent cff99cf1fa
commit 4d19220742
1 changed files with 20 additions and 114 deletions
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bsps/shared/grlib/can/grcan.c
+20 -114
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@@ -18,6 +18,7 @@
#include <rtems/bspIo.h>
#include <grlib/grcan.h>
#include <grlib/canbtrs.h>
#include <drvmgr/drvmgr.h>
#include <grlib/ambapp_bus.h>
#include <grlib/ambapp.h>
@@ -180,6 +181,17 @@ static void grcan_interrupt(void *arg);
#define NELEM(a) ((int) (sizeof (a) / sizeof (a[0])))
/* GRCAN nominal boundaries for baud-rate paramters */
static struct grlib_canbtrs_ranges grcan_btrs_ranges = {
.max_scaler = 256*8, /* scaler is multiplied by BPR in steps 1,2,4,8 */
.has_bpr = 1,
.divfactor = 2,
.min_tseg1 = 1,
.max_tseg1 = 15,
.min_tseg2 = 2,
.max_tseg2 = 8,
};
static int grcan_count = 0;
static struct grcan_priv *priv_tab[GRCAN_COUNT_MAX];
@@ -564,117 +576,6 @@ static unsigned int grcan_hw_txspace(
return left / GRCAN_MSG_SIZE - WRAP_AROUND_TX_MSGS;
}
#define MIN_TSEG1 1
#define MIN_TSEG2 2
#define MAX_TSEG1 14
#define MAX_TSEG2 8
static int grcan_calc_timing(
unsigned int baud, /* The requested BAUD to calculate timing for */
unsigned int core_hz, /* Frequency in Hz of GRCAN Core */
unsigned int sampl_pt,
struct grcan_timing *timing /* result is placed here */
)
{
int best_error = 1000000000;
int error;
int best_tseg = 0, best_brp = 0, brp = 0;
int tseg = 0, tseg1 = 0, tseg2 = 0;
int sjw = 1;
/* Default to 90% */
if ((sampl_pt < 50) || (sampl_pt > 99)) {
sampl_pt = GRCAN_SAMPLING_POINT;
}
if ((baud < 5000) || (baud > 1000000)) {
/* invalid speed mode */
return -1;
}
/* find best match, return -2 if no good reg
* combination is available for this frequency
*/
/* some heuristic specials */
if (baud > ((1000000 + 500000) / 2))
sampl_pt = 75;
if (baud < ((12500 + 10000) / 2))
sampl_pt = 75;
/* tseg even = round down, odd = round up */
for (
tseg = (MIN_TSEG1 + MIN_TSEG2 + 2) * 2;
tseg <= (MAX_TSEG2 + MAX_TSEG1 + 2) * 2 + 1;
tseg++
) {
brp = core_hz / ((1 + tseg / 2) * baud) + tseg % 2;
if (
(brp <= 0) ||
((brp > 256 * 1) && (brp <= 256 * 2) && (brp & 0x1)) ||
((brp > 256 * 2) && (brp <= 256 * 4) && (brp & 0x3)) ||
((brp > 256 * 4) && (brp <= 256 * 8) && (brp & 0x7)) ||
(brp > 256 * 8)
)
continue;
error = baud - core_hz / (brp * (1 + tseg / 2));
if (error < 0) {
error = -error;
}
if (error <= best_error) {
best_error = error;
best_tseg = tseg / 2;
best_brp = brp - 1;
}
}
if (best_error && (baud / best_error < 10)) {
return -2;
} else if (!timing)
return 0; /* nothing to store result in, but a valid bitrate can be calculated */
tseg2 = best_tseg - (sampl_pt * (best_tseg + 1)) / 100;
if (tseg2 < MIN_TSEG2) {
tseg2 = MIN_TSEG2;
}
if (tseg2 > MAX_TSEG2) {
tseg2 = MAX_TSEG2;
}
tseg1 = best_tseg - tseg2 - 2;
if (tseg1 > MAX_TSEG1) {
tseg1 = MAX_TSEG1;
tseg2 = best_tseg - tseg1 - 2;
}
/* Get scaler and BRP from pseudo BRP */
if (best_brp <= 256) {
timing->scaler = best_brp;
timing->bpr = 0;
} else if (best_brp <= 256 * 2) {
timing->scaler = ((best_brp + 1) >> 1) - 1;
timing->bpr = 1;
} else if (best_brp <= 256 * 4) {
timing->scaler = ((best_brp + 1) >> 2) - 1;
timing->bpr = 2;
} else {
timing->scaler = ((best_brp + 1) >> 3) - 1;
timing->bpr = 3;
}
timing->ps1 = tseg1 + 1;
timing->ps2 = tseg2;
timing->rsj = sjw;
return 0;
}
static int grcan_hw_read_try(
struct grcan_priv *pDev,
struct grcan_regs *regs,
@@ -1282,7 +1183,10 @@ void *grcan_open(int dev_no)
pDev->sfilter.code = 0x00000000;
/* Calculate default timing register values */
grcan_calc_timing(GRCAN_DEFAULT_BAUD,pDev->corefreq_hz,GRCAN_SAMPLING_POINT,&pDev->config.timing);
grlib_canbtrs_calc_timing(
GRCAN_DEFAULT_BAUD, pDev->corefreq_hz,
GRCAN_SAMPLING_POINT, &grcan_btrs_ranges,
(struct grlib_canbtrs_timing *)&pDev->config.timing);
if ( grcan_alloc_buffers(pDev,1,1) ) {
ret = NULL;
@@ -1725,8 +1629,10 @@ int grcan_set_speed(void *d, unsigned int speed)
return -1;
/* get speed rate from argument */
ret = grcan_calc_timing(speed, pDev->corefreq_hz, GRCAN_SAMPLING_POINT, &timing);
if ( ret )
ret = grlib_canbtrs_calc_timing(
speed, pDev->corefreq_hz, GRCAN_SAMPLING_POINT,
&grcan_btrs_ranges, (struct grlib_canbtrs_timing *)&timing);
if (ret)
return -2;
/* save timing/speed */