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leon,can: introduce common CAN baud-rate calculation function

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Reimplemented the baud-rate algorithm from scratch to cope with
GRCAN, GRCANFD and OC_CAN devices.

Update #4323.
This commit is contained in:
Daniel Hellstrom
2019-04-12 11:01:38 +02:00
parent 68c882ef45
commit cff99cf1fa
7 changed files with 246 additions and 1 deletions
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1
bsps/headers.am
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@@ -57,6 +57,7 @@ include_grlib_HEADERS += ../../bsps/include/grlib/apbuart_termios.h
include_grlib_HEADERS += ../../bsps/include/grlib/b1553brm.h
include_grlib_HEADERS += ../../bsps/include/grlib/b1553rt.h
include_grlib_HEADERS += ../../bsps/include/grlib/bspcommon.h
include_grlib_HEADERS += ../../bsps/include/grlib/canbtrs.h
include_grlib_HEADERS += ../../bsps/include/grlib/canmux.h
include_grlib_HEADERS += ../../bsps/include/grlib/cons.h
include_grlib_HEADERS += ../../bsps/include/grlib/debug_defs.h

94
bsps/include/grlib/canbtrs.h Normal file
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@@ -0,0 +1,94 @@
/* SPDX-License-Identifier: BSD-2-Clause */
/**
* @file
* @ingroup can
* @brief Common CAN baud-rate routines for OCCAN/GRCAN/GRCANFD controllers
*/
/*
* Copyright (C) 2019, 2020 Cobham Gaisler AB
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef __GRLIB_CANBTRS_H__
#define __GRLIB_CANBTRS_H__
/**
* @defgroup can CAN
*
* @ingroup RTEMSBSPsSharedGRLIB
*
* @brief CAN routines shared between OCCAN, GRCAN and GRCANFD controllers
*
* @{
*/
#ifdef __cplusplus
extern "C" {
#endif
/* CAN Baud-rate parameters, range of valid parameter values */
struct grlib_canbtrs_ranges {
unsigned int max_scaler;
char has_bpr;
unsigned char divfactor;
unsigned char min_tseg1;
unsigned char max_tseg1;
unsigned char min_tseg2;
unsigned char max_tseg2;
};
struct grlib_canbtrs_timing {
unsigned char scaler;
unsigned char ps1;
unsigned char ps2;
unsigned char rsj;
unsigned char bpr;
};
/* @brief Calculate CAN baud-rate generation parameters from requested baud-rate
*
* @param baud The CAN baud rate requested
* @param core_hz Input clock [Hz] to CAN core
* @param sampl_pt CAN sample point in %, 80 means 80%
* @param br CAN Baud-rate parameters limitations
* @param[out] timing result is placed here
*
* @retval 0 Baud-rate parameters sucessfully calculated
* @retval negative Failure to generate parameters with less than 5% error
* margin from requested baud-rate
*/
int grlib_canbtrs_calc_timing(
unsigned int baud,
unsigned int core_hz,
unsigned int sampl_pt,
struct grlib_canbtrs_ranges *br,
struct grlib_canbtrs_timing *timing
);
#ifdef __cplusplus
}
#endif
#endif

3
bsps/include/grlib/grcan.h
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@@ -1,6 +1,7 @@
/**
* @file
* @ingroup can
* @brief Driver API for the GRLIB GRCAN and GRCANFD controllers
*/
/*
@@ -25,6 +26,8 @@
* @{
*/
#include <stdint.h>
#ifdef __cplusplus
extern "C" {
#endif

2
bsps/include/grlib/occan.h
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@@ -1,7 +1,7 @@
/**
* @file
* @ingroup can
* @brief Gaisler wrapper to OpenCores CAN - driver interface
* @brief Driver API for GRLIB wrapper to OpenCores CAN
*/
/*

1
bsps/shared/grlib-sources.am
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@@ -20,6 +20,7 @@ librtemsbsp_a_SOURCES += ../../../../../../bsps/shared/grlib/ascs/grascs.c
librtemsbsp_a_SOURCES += ../../../../../../bsps/shared/grlib/btimer/gptimer.c
librtemsbsp_a_SOURCES += ../../../../../../bsps/shared/grlib/btimer/tlib.c
librtemsbsp_a_SOURCES += ../../../../../../bsps/shared/grlib/btimer/tlib_ckinit.c
librtemsbsp_a_SOURCES += ../../../../../../bsps/shared/grlib/can/canbtrs.c
librtemsbsp_a_SOURCES += ../../../../../../bsps/shared/grlib/can/canmux.c
librtemsbsp_a_SOURCES += ../../../../../../bsps/shared/grlib/can/grcan.c
librtemsbsp_a_SOURCES += ../../../../../../bsps/shared/grlib/can/occan.c

144
bsps/shared/grlib/can/canbtrs.c Normal file
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@@ -0,0 +1,144 @@
/* SPDX-License-Identifier: BSD-2-Clause */
/**
* @file
*
* @ingroup can
*
* @brief Common CAN baud-rate routines for OCCAN/GRCAN/GRCANFD controllers
*
* Implements common routines for calculating CAN baud-rate parameters from
* a user provided baud-rate speed.
*/
/*
* Copyright (C) 2019, 2020 Cobham Gailer AB
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <grlib/canbtrs.h>
/*#define GRLIB_CANBTRS_DEBUG*/
/* Calculate CAN baud-rate generation parameters from requested baud-rate */
int grlib_canbtrs_calc_timing(
unsigned int baud,
unsigned int core_hz,
unsigned int sampl_pt,
struct grlib_canbtrs_ranges *br,
struct grlib_canbtrs_timing *timing
)
{
int best_error = 2000000000, best_tseg=0, best_scaler=0;
int tseg=0, tseg1=0, tseg2=0, sc, tmp, error;
/* Default to 80% sample point */
if ((sampl_pt < 50) || (sampl_pt > 99))
sampl_pt = 80;
/* step though all TSEG1+TSEG2 values possible */
for (tseg = (br->min_tseg1 + br->min_tseg2);
tseg <= (br->max_tseg1 + br->max_tseg2);
tseg++) {
/* calculate scaler */
tmp = ((br->divfactor + tseg) * baud);
sc = (core_hz * 2)/ tmp - core_hz / tmp;
if (sc <= 0 || sc > br->max_scaler)
continue;
if (br->has_bpr &&
(((sc > 256 * 1) && (sc <= 256 * 2) && (sc & 0x1)) ||
((sc > 256 * 2) && (sc <= 256 * 4) && (sc & 0x3)) ||
((sc > 256 * 4) && (sc <= 256 * 8) && (sc & 0x7))))
continue;
error = baud - core_hz / (sc * (br->divfactor + tseg));
#ifdef GRLIB_CANBTRS_DEBUG
printf(" baud=%d, tseg=%d, sc=%d, error=%d\n",
baud, tseg, sc, error);
#endif
if (error < 0)
error = -error;
/* tseg is increasing, so we accept higher tseg with the same
* baudrate to get better sampling point.
*/
if (error <= best_error) {
best_error = error;
best_tseg = tseg;
best_scaler = sc;
#ifdef GRLIB_CANBTRS_DEBUG
printf(" ! best baud=%d\n",
core_hz/(sc * (br->divfactor + tseg)));
#endif
}
}
/* return an error if 5% off baud-rate */
if (best_error && (baud / best_error <= 5)) {
return -2;
} else if (!timing) {
return 0; /* nothing to store result in, but a valid bitrate can be calculated */
}
tseg2 = (best_tseg + br->divfactor) -
((sampl_pt * (best_tseg + br->divfactor)) / 100);
if (tseg2 < br->min_tseg2) {
tseg2 = br->min_tseg2;
} else if (tseg2 > br->max_tseg2) {
tseg2 = br->max_tseg2;
}
tseg1 = best_tseg - tseg2;
if (tseg1 > br->max_tseg1) {
tseg1 = br->max_tseg1;
tseg2 = best_tseg - tseg1;
} else if (tseg1 < br->min_tseg1) {
tseg1 = br->min_tseg1;
tseg2 = best_tseg - tseg1;
}
/* Get scaler and BPR from pseudo SCALER clock */
if (best_scaler <= 256) {
timing->scaler = best_scaler - 1;
timing->bpr = 0;
} else if (best_scaler <= 256 * 2) {
timing->scaler = ((best_scaler + 1) >> 1) - 1;
timing->bpr = 1;
} else if (best_scaler <= 256 * 4) {
timing->scaler = ((best_scaler + 1) >> 2) - 1;
timing->bpr = 2;
} else {
timing->scaler = ((best_scaler + 1) >> 3) - 1;
timing->bpr = 3;
}
timing->ps1 = tseg1;
timing->ps2 = tseg2;
timing->rsj = 1;
#ifdef GRLIB_CANBTRS_DEBUG
printf(" ! result: sc=%d,bpr=%d,ps1=%d,ps2=%d\n", timing->scaler, timing->bpr, timing->ps1, timing->ps2);
#endif
return 0;
}

2
spec/build/bsps/objgrlib.yml
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@@ -21,6 +21,7 @@ install:
- bsps/include/grlib/b1553brm.h
- bsps/include/grlib/b1553rt.h
- bsps/include/grlib/bspcommon.h
- bsps/include/grlib/canbtrs.h
- bsps/include/grlib/canmux.h
- bsps/include/grlib/cons.h
- bsps/include/grlib/debug_defs.h
@@ -99,6 +100,7 @@ source:
- bsps/shared/grlib/btimer/gptimer.c
- bsps/shared/grlib/btimer/tlib.c
- bsps/shared/grlib/btimer/tlib_ckinit.c
- bsps/shared/grlib/can/canbtrs.c
- bsps/shared/grlib/can/canmux.c
- bsps/shared/grlib/can/grcan.c
- bsps/shared/grlib/can/occan.c