On Fri, Oct 16, 2020, 6:50 AM Daniel Hellstrom <dan...@gaisler.com> wrote:
> Reimplemented the baud-rate algorithm from scratch to cope with
> GRCAN, GRCANFD and OC_CAN devices.
> ---
> bsps/headers.am | 1 +
> bsps/include/grlib/canbtrs.h | 80 ++++++++++++++++++++++
> bsps/shared/grlib-sources.am | 1 +
> bsps/shared/grlib/can/canbtrs.c | 143
> ++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 225 insertions(+)
> create mode 100644 bsps/include/grlib/canbtrs.h
> create mode 100644 bsps/shared/grlib/can/canbtrs.c
>
> diff --git a/bsps/headers.am b/bsps/headers.am
> index 5af7e43..2c9b31d 100644
> --- a/bsps/headers.am
> +++ b/bsps/headers.am
> @@ -34,6 +34,7 @@ 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
> diff --git a/bsps/include/grlib/canbtrs.h b/bsps/include/grlib/canbtrs.h
> new file mode 100644
> index 0000000..3b2118b
> --- /dev/null
> +++ b/bsps/include/grlib/canbtrs.h
> @@ -0,0 +1,80 @@
> +/* 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__
> +
> +#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;
> +};
> +
> +/* 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 timing result is placed here
> + */
>
I thought we used @ notation for Doxygen not leading backslash in front of
commands.
+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
> diff --git a/bsps/shared/grlib-sources.am b/bsps/shared/grlib-sources.am
> index 512a48c..f2ad1bf 100644
> --- a/bsps/shared/grlib-sources.am
> +++ b/bsps/shared/grlib-sources.am
> @@ -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
> diff --git a/bsps/shared/grlib/can/canbtrs.c
> b/bsps/shared/grlib/can/canbtrs.c
> new file mode 100644
> index 0000000..d28efbc
> --- /dev/null
> +++ b/bsps/shared/grlib/can/canbtrs.c
> @@ -0,0 +1,143 @@
> +/* 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, 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 */
> + sc = core_hz / ((br->divfactor + tseg) * baud);
> + 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;
> +}
> --
> 2.7.4
>
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