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108 lines
3.1 KiB
C
108 lines
3.1 KiB
C
/*
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* Copyright 2024 Google LLC
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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 "drivers/crc.h"
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#include "drivers/flash.h"
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#include "drivers/periph_config.h"
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#include "stm32f2xx_crc.h"
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#include "stm32f2xx_rcc.h"
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#include <inttypes.h>
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static void prv_enable_crc_clock(void) {
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periph_config_enable(RCC_AHB1PeriphClockCmd, RCC_AHB1Periph_CRC);
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}
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static void prv_disable_crc_clock(void) {
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periph_config_disable(RCC_AHB1PeriphClockCmd, RCC_AHB1Periph_CRC);
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}
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static void prv_calculate_incremental_start(void) {
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prv_enable_crc_clock();
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CRC_ResetDR();
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}
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static void prv_calculate_incremental_words(const uint32_t* data, unsigned int data_length) {
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CRC_CalcBlockCRC((uint32_t*) data, data_length);
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}
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static uint32_t prv_calculate_incremental_remaining_bytes(const uint8_t* data,
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unsigned int data_length) {
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uint32_t crc_value;
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if (data_length >= 4) {
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const unsigned int num_words = data_length / 4;
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prv_calculate_incremental_words((uint32_t*) data, num_words);
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data += num_words * 4;
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data_length -= num_words * 4;
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}
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if (data_length) {
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uint32_t last_word = 0;
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for (unsigned int i = 0; i < data_length; ++i) {
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last_word = (last_word << 8) | data[i];
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}
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crc_value = CRC_CalcCRC(last_word);
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} else {
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crc_value = CRC_GetCRC();
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}
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return crc_value;
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}
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static void prv_calculate_incremental_stop(void) {
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prv_disable_crc_clock();
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}
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uint32_t crc_calculate_bytes(const uint8_t* data, unsigned int data_length) {
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prv_calculate_incremental_start();
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// First calculate the CRC of the whole words, since the hardware works 4
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// bytes at a time.
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uint32_t* data_words = (uint32_t*) data;
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const unsigned int num_words = data_length / 4;
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prv_calculate_incremental_words(data_words, num_words);
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const unsigned int num_remaining_bytes = data_length % 4;
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const uint32_t res =
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prv_calculate_incremental_remaining_bytes(data + (num_words * 4), num_remaining_bytes);
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prv_calculate_incremental_stop();
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return (res);
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}
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uint32_t crc_calculate_flash(uint32_t address, unsigned int num_bytes) {
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prv_calculate_incremental_start();
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const unsigned int chunk_size = 128;
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uint8_t buffer[chunk_size];
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while (num_bytes > chunk_size) {
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flash_read_bytes(buffer, address, chunk_size);
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prv_calculate_incremental_words((const uint32_t*) buffer, chunk_size / 4);
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num_bytes -= chunk_size;
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address += chunk_size;
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}
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flash_read_bytes(buffer, address, num_bytes);
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const uint32_t res = prv_calculate_incremental_remaining_bytes(buffer, num_bytes);
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prv_calculate_incremental_stop();
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return (res);
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}
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