mirror of https://github.com/ARMmbed/mbed-os.git
100 lines
3.4 KiB
C
100 lines
3.4 KiB
C
/* mbed Microcontroller Library
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* Copyright (c) 2019, Arm Limited and affiliates.
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "crc_api.h"
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#include "mbed_assert.h"
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#include "mbed_error.h"
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#include "cyhal_crc.h"
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#include "objects.h"
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#if DEVICE_CRC
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#ifdef __cplusplus
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extern "C" {
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#endif
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static cyhal_crc_t cy_crc;
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static crc_algorithm_t cy_crc_cfg;
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static bool cy_crc_initialized = false;
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// Reverses width least significant bits of 32 bit input. Any bits more
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// significant than width are dropped.
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static uint32_t reverse(uint8_t width, uint32_t in)
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{
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MBED_ASSERT(width <= 32);
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return __RBIT(in) >> (32 - width);
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}
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void hal_crc_compute_partial_start(const crc_mbed_config_t *config)
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{
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if (!cy_crc_initialized) {
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if (CY_RSLT_SUCCESS != cyhal_crc_init(&cy_crc)) {
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MBED_ERROR(MBED_MAKE_ERROR(MBED_MODULE_DRIVER, MBED_ERROR_CODE_FAILED_OPERATION), "cyhal_crc_init");
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}
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cy_crc_initialized = true;
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}
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if (!HAL_CRC_IS_SUPPORTED(config->polynomial, config->width)) {
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MBED_ERROR(MBED_MAKE_ERROR(MBED_MODULE_DRIVER, MBED_ERROR_CODE_UNSUPPORTED), "unsupported CRC width");
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}
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cy_crc_cfg.width = config->width;
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cy_crc_cfg.polynomial = config->polynomial;
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cy_crc_cfg.lfsrInitState = config->initial_xor;
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cy_crc_cfg.dataXor = 0;
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cy_crc_cfg.dataReverse = config->reflect_in ? 1 : 0;
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cy_crc_cfg.remReverse = config->reflect_out ? 1 : 0;
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// There is an incongruity between what MBeds CRC spec expects and what
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// PSoC6 hardware actually performs when it comes to the final XOR and
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// remainder reversal: MBed expects the final remainder to be reversed then
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// XORed with remXor while PSoC6s CRC, however, performs the final XOR with
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// remXor then reverses the resulting value. Since Rev(A) XOR B == Rev( A
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// XOR Rev(B) ), a simple fix is to reverse remXor if reflect_out is true.
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cy_crc_cfg.remXor = config->reflect_out ? reverse(config->width, config->final_xor) : config->final_xor;
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if (CY_RSLT_SUCCESS != cyhal_crc_start(&cy_crc, &cy_crc_cfg)) {
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MBED_ERROR(MBED_MAKE_ERROR(MBED_MODULE_DRIVER, MBED_ERROR_CODE_FAILED_OPERATION), "cyhal_crc_start");
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}
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}
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void hal_crc_compute_partial(const uint8_t *data, const size_t size)
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{
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MBED_ASSERT(cy_crc_initialized);
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if (NULL == data || 0 == size) {
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return;
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}
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if (CY_RSLT_SUCCESS != cyhal_crc_compute(&cy_crc, data, size)) {
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MBED_ERROR(MBED_MAKE_ERROR(MBED_MODULE_DRIVER, MBED_ERROR_CODE_FAILED_OPERATION), "cyhal_crc_compute");
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}
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}
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uint32_t hal_crc_get_result(void)
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{
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uint32_t value;
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if (CY_RSLT_SUCCESS != cyhal_crc_finish(&cy_crc, &value)) {
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MBED_ERROR(MBED_MAKE_ERROR(MBED_MODULE_DRIVER, MBED_ERROR_CODE_FAILED_OPERATION), "cyhal_crc_finish");
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}
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cyhal_crc_free(&cy_crc);
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cy_crc_initialized = false;
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return value;
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}
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#ifdef __cplusplus
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};
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#endif
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#endif // DEVICE_CRC
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