openmv/ports/alif/omv_crc.c
iabdalkader 9704ed8c62 ports/alif: Add support for CRC32.
Signed-off-by: iabdalkader <i.abdalkader@gmail.com>
2025-09-25 18:05:57 +02:00

103 lines
3.3 KiB
C

/*
* SPDX-License-Identifier: MIT
*
* Copyright (C) 2023-2024 OpenMV, LLC.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "crc.h"
#include "global_map.h"
#include "omv_crc.h"
// There seems to be a mismatch between how the Alif HW CRC32 algorithm
// works and the other HW CRCs and the software implementation.
// Just leaving this here just in case it works on a different series.
#if 0
#define CRC0 ((CRC_Type *) CRC0_BASE)
static bool crc32_initialized = false;
static void crc_calculate(CRC_Type *crc, const void *buf, uint32_t len, uint32_t *value);
static void omv_crc32_init(void) {
CRC0->CRC_CONTROL = CRC_32C |
CRC_CUSTOM_POLY |
CRC_ALGO_32_BIT_SIZE;
CRC0->CRC_SEED = OMV_CRC32_INIT;
CRC0->CRC_POLY_CUSTOM = OMV_CRC32_POLY;
crc32_initialized = true;
}
uint32_t omv_crc32_start(const void *buf, size_t len) {
uint32_t result = OMV_CRC32_INIT;
if (!crc32_initialized) {
omv_crc32_init();
}
if (len == 0) {
return OMV_CRC32_INIT;
}
crc_calculate(CRC0, buf, len, &result);
return result;
}
uint32_t omv_crc32_update(uint32_t crc, const void *buf, size_t len) {
uint32_t result = crc;
if (!crc32_initialized) {
omv_crc32_init();
}
if (len == 0) {
return crc;
}
crc_calculate(CRC0, buf, len, &result);
return result;
}
static void crc_calculate(CRC_Type *crc, const void *buf, uint32_t len, uint32_t *value) {
const uint8_t *data = (const uint8_t *) buf;
if ((len % 4) == 0) {
// Use hardware only if length is multiple of 4
crc->CRC_SEED = *value;
crc->CRC_CONTROL |= CRC_INIT_BIT;
// Hardware path - process all data as 32-bit words
const uint32_t *data32 = (const uint32_t *) data;
for (uint32_t i = 0; i < len / 4; i++) {
crc->CRC_DATA_IN_32_0 = data32[i];
}
*value = crc->CRC_OUT;
} else {
// Software path - use lookup table
uint32_t result = *value;
extern const uint32_t crc32_table[256];
for (uint32_t i = 0; i < len; i++) {
uint8_t index = (result >> 24) ^ data[i];
result = (result << 8) ^ crc32_table[index];
}
*value = result;
}
}
#endif