forked from Imagelibrary/rtems
cff99cf1fa
Reimplemented the baud-rate algorithm from scratch to cope with GRCAN, GRCANFD and OC_CAN devices. Update #4323.
95 lines
2.9 KiB
C
95 lines
2.9 KiB
C
/* SPDX-License-Identifier: BSD-2-Clause */
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/**
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* @file
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* @ingroup can
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* @brief Common CAN baud-rate routines for OCCAN/GRCAN/GRCANFD controllers
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*/
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/*
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* Copyright (C) 2019, 2020 Cobham Gaisler AB
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef __GRLIB_CANBTRS_H__
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#define __GRLIB_CANBTRS_H__
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/**
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* @defgroup can CAN
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*
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* @ingroup RTEMSBSPsSharedGRLIB
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*
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* @brief CAN routines shared between OCCAN, GRCAN and GRCANFD controllers
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*
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* @{
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*/
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* CAN Baud-rate parameters, range of valid parameter values */
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struct grlib_canbtrs_ranges {
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unsigned int max_scaler;
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char has_bpr;
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unsigned char divfactor;
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unsigned char min_tseg1;
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unsigned char max_tseg1;
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unsigned char min_tseg2;
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unsigned char max_tseg2;
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};
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struct grlib_canbtrs_timing {
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unsigned char scaler;
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unsigned char ps1;
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unsigned char ps2;
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unsigned char rsj;
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unsigned char bpr;
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};
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/* @brief Calculate CAN baud-rate generation parameters from requested baud-rate
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*
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* @param baud The CAN baud rate requested
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* @param core_hz Input clock [Hz] to CAN core
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* @param sampl_pt CAN sample point in %, 80 means 80%
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* @param br CAN Baud-rate parameters limitations
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* @param[out] timing result is placed here
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*
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* @retval 0 Baud-rate parameters sucessfully calculated
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* @retval negative Failure to generate parameters with less than 5% error
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* margin from requested baud-rate
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*/
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int grlib_canbtrs_calc_timing(
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unsigned int baud,
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unsigned int core_hz,
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unsigned int sampl_pt,
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struct grlib_canbtrs_ranges *br,
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struct grlib_canbtrs_timing *timing
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);
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#ifdef __cplusplus
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}
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#endif
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#endif
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