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authorDaniel Hellstrom <daniel@gaisler.com>2019-04-12 12:36:58 +0200
committerDaniel Hellstrom <daniel@gaisler.com>2021-03-11 17:31:21 +0100
commit4d192207421d8f7918028fb069df0c6167b6b992 (patch)
tree3197cbd91f472e20e56c7300ab4e5010df7e9141
parentcff99cf1fae2ff2b019c7f3b1827bb7fe8ee7d83 (diff)
downloadrtems-4d192207421d8f7918028fb069df0c6167b6b992.tar.bz2
leon,grcan: use common CAN baud-rate calculation routine
Update #4323.
-rw-r--r--bsps/shared/grlib/can/grcan.c134
1 files changed, 20 insertions, 114 deletions
diff --git a/bsps/shared/grlib/can/grcan.c b/bsps/shared/grlib/can/grcan.c
index a446d04c28..c4e6f18b04 100644
--- a/bsps/shared/grlib/can/grcan.c
+++ b/bsps/shared/grlib/can/grcan.c
@@ -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 */