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

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Update #4306.
This commit is contained in:
Daniel Hellstrom
2019-04-12 12:54:54 +02:00
parent 78b45cc561
commit 7db032cf02
1 changed files with 40 additions and 109 deletions
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149
bsps/shared/grlib/can/occan.c
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@@ -19,6 +19,7 @@
#include <drvmgr/drvmgr.h>
#include <grlib/ambapp_bus.h>
#include <grlib/occan.h>
#include <grlib/canbtrs.h>
#include <grlib/grlib_impl.h>
@@ -185,19 +186,20 @@ typedef struct {
#define pelican_regs pelican32_regs
#endif
/* Default sampling point in % */
#define OCCAN_SAMPLING_POINT 90
#define MAX_TSEG2 7
#define MAX_TSEG1 15
/* OCCAN baud-rate paramter boundaries */
struct grlib_canbtrs_ranges occan_btrs_ranges = {
.max_scaler = 64,
.has_bpr = 0,
.divfactor = 1,
.min_tseg1 = 1,
.max_tseg1 = 16,
.min_tseg2 = 1,
.max_tseg2 = 8,
};
#if 0
typedef struct {
unsigned char brp;
unsigned char sjw;
unsigned char tseg1;
unsigned char tseg2;
unsigned char sam;
} occan_speed_regs;
#endif
typedef struct {
unsigned char btr0;
unsigned char btr1;
@@ -251,7 +253,9 @@ static CANMsg *occan_fifo_claim_get(occan_fifo *fifo);
static void occan_fifo_clr(occan_fifo *fifo);
/**** Hardware related Interface ****/
static int occan_calc_speedregs(unsigned int clock_hz, unsigned int rate, occan_speed_regs *result);
static void convert_timing_to_btrs(
struct grlib_canbtrs_timing *t,
occan_speed_regs *btrs);
static int occan_set_speedregs(occan_priv *priv, occan_speed_regs *timing);
static void pelican_init(occan_priv *priv);
static void pelican_open(occan_priv *priv);
@@ -765,6 +769,7 @@ static void pelican_init(occan_priv *priv){
static void pelican_open(occan_priv *priv){
int ret;
struct grlib_canbtrs_timing timing;
/* Set defaults */
priv->speed = OCCAN_SPEED_250K;
@@ -783,13 +788,19 @@ static void pelican_open(occan_priv *priv){
*/
WRITE_REG(priv, &priv->regs->clkdiv, (1<<PELICAN_CDR_MODE_BITS) | (DEFAULT_CLKDIV & PELICAN_CDR_DIV));
ret = occan_calc_speedregs(priv->sys_freq_hz,priv->speed,&priv->timing);
if ( ret ){
ret = grlib_canbtrs_calc_timing(
priv->speed, priv->sys_freq_hz,
OCCAN_SAMPLING_POINT, &occan_btrs_ranges,
(struct grlib_canbtrs_timing *)&timing);
if ( ret ) {
/* failed to set speed for this system freq, try with 50K instead */
priv->speed = OCCAN_SPEED_50K;
occan_calc_speedregs(priv->sys_freq_hz, priv->speed,
&priv->timing);
grlib_canbtrs_calc_timing(
priv->speed, priv->sys_freq_hz,
OCCAN_SAMPLING_POINT, &occan_btrs_ranges,
(struct grlib_canbtrs_timing *)&timing);
}
convert_timing_to_btrs(&timing, &priv->timing);
/* disable all interrupts */
WRITE_REG(priv, &priv->regs->inten, 0);
@@ -983,97 +994,13 @@ static void pelican_set_accept(occan_priv *priv, unsigned char *acode, unsigned
WRITE_REG(priv, amask3, amask[3]);
}
/* This function calculates BTR0 and BTR1 values for a given bitrate.
*
* Set communication parameters.
* \param clock_hz OC_CAN Core frequency in Hz.
* \param rate Requested baud rate in bits/second.
* \param result Pointer to where resulting BTRs will be stored.
* \return zero if successful to calculate a baud rate.
*/
static int occan_calc_speedregs(unsigned int clock_hz, unsigned int rate, occan_speed_regs *result)
static void convert_timing_to_btrs(
struct grlib_canbtrs_timing *t,
occan_speed_regs *btrs)
{
int best_error = 1000000000;
int error;
int best_tseg=0, best_brp=0, brp=0;
int tseg=0, tseg1=0, tseg2=0;
int sjw = 0;
int clock = clock_hz / 2;
int sampl_pt = 90;
if ( (rate<5000) || (rate>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 (rate > ((1000000 + 500000) / 2))
sampl_pt = 75;
if (rate < ((12500 + 10000) / 2))
sampl_pt = 75;
if (rate < ((100000 + 125000) / 2))
sjw = 1;
/* tseg even = round down, odd = round up */
for (tseg = (0 + 0 + 2) * 2;
tseg <= (MAX_TSEG2 + MAX_TSEG1 + 2) * 2 + 1;
tseg++)
{
brp = clock / ((1 + tseg / 2) * rate) + tseg % 2;
if ((brp == 0) || (brp > 64))
continue;
error = rate - clock / (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 && (rate / best_error < 10))
{
printk("OCCAN: bitrate %d is not possible with %d Hz clock\n\r",rate, clock);
return -2;
}else if ( !result )
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 < 0)
{
tseg2 = 0;
}
if (tseg2 > MAX_TSEG2)
{
tseg2 = MAX_TSEG2;
}
tseg1 = best_tseg - tseg2 - 2;
if (tseg1 > MAX_TSEG1)
{
tseg1 = MAX_TSEG1;
tseg2 = best_tseg - tseg1 - 2;
}
result->btr0 = (sjw<<OCCAN_BUSTIM_SJW_BIT) | (best_brp&OCCAN_BUSTIM_BRP);
result->btr1 = (0<<7) | (tseg2<<OCCAN_BUSTIM_TSEG2_BIT) | tseg1;
return 0;
btrs->btr0 = (t->rsj << OCCAN_BUSTIM_SJW_BIT) |
(t->scaler & OCCAN_BUSTIM_BRP);
btrs->btr1 = (0<<7) | (t->ps2 << OCCAN_BUSTIM_TSEG2_BIT) | t->ps1;
}
static int occan_set_speedregs(occan_priv *priv, occan_speed_regs *timing)
@@ -1441,7 +1368,7 @@ static rtems_device_driver occan_write(rtems_device_major_number major, rtems_de
static rtems_device_driver occan_ioctl(rtems_device_major_number major, rtems_device_minor_number minor, void *arg)
{
int ret;
occan_speed_regs timing;
struct grlib_canbtrs_timing timing;
occan_priv *can;
struct drvmgr_dev *dev;
unsigned int speed;
@@ -1467,7 +1394,11 @@ static rtems_device_driver occan_ioctl(rtems_device_major_number major, rtems_de
/* get speed rate from argument */
speed = (unsigned int)ioarg->buffer;
ret = occan_calc_speedregs(can->sys_freq_hz,speed,&timing);
/* Calculate default timing register values */
ret = grlib_canbtrs_calc_timing(
speed, can->sys_freq_hz,
OCCAN_SAMPLING_POINT, &occan_btrs_ranges,
(struct grlib_canbtrs_timing *)&timing);
if ( ret )
return RTEMS_INVALID_NAME; /* EINVAL */
@@ -1476,7 +1407,7 @@ static rtems_device_driver occan_ioctl(rtems_device_major_number major, rtems_de
/* save timing/speed */
can->speed = speed;
can->timing = timing;
convert_timing_to_btrs(&timing, &can->timing);
break;
case OCCAN_IOC_SET_BTRS: