Files
pebble/src/fw/services/common/prf_update.c
2025-01-27 11:38:16 -08:00

80 lines
2.6 KiB
C

/*
* Copyright 2024 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "drivers/flash.h"
#include "flash_region/flash_region.h"
#include "system/bootbits.h"
#include "system/firmware_storage.h"
#include "system/logging.h"
#include "util/math.h"
// Don't allow PRF updating when we're in PRF
#ifndef RECOVERY_FW
static void prv_do_update(void) {
PBL_LOG(LOG_LEVEL_INFO, "Updating PRF!");
flash_prf_set_protection(false);
bool saved_sleep_when_idle = flash_get_sleep_when_idle();
flash_sleep_when_idle(false);
FirmwareDescription description =
firmware_storage_read_firmware_description(FLASH_REGION_FIRMWARE_SCRATCH_BEGIN);
if (!firmware_storage_check_valid_firmware_description(FLASH_REGION_FIRMWARE_SCRATCH_BEGIN,
&description)) {
PBL_LOG(LOG_LEVEL_WARNING, "Invalid recovery firmware CRC in SPI flash!");
goto done;
}
const uint32_t total_length = description.description_length + description.firmware_length;
PBL_LOG(LOG_LEVEL_DEBUG, "Erasing previous PRF...");
flash_region_erase_optimal_range(FLASH_REGION_SAFE_FIRMWARE_BEGIN,
FLASH_REGION_SAFE_FIRMWARE_BEGIN,
FLASH_REGION_SAFE_FIRMWARE_BEGIN + total_length,
FLASH_REGION_SAFE_FIRMWARE_END);
PBL_LOG(LOG_LEVEL_DEBUG, "Copying PRF from scratch to the PRF slot");
uint8_t buffer[512];
uint32_t offset = 0;
while (offset < total_length) {
const uint32_t chunk_size = MIN(sizeof(buffer), (total_length - offset));
flash_read_bytes(buffer, FLASH_REGION_FIRMWARE_SCRATCH_BEGIN + offset, chunk_size);
flash_write_bytes(buffer, FLASH_REGION_SAFE_FIRMWARE_BEGIN + offset, chunk_size);
offset += chunk_size;
}
done:
flash_prf_set_protection(true);
flash_sleep_when_idle(saved_sleep_when_idle);
PBL_LOG(LOG_LEVEL_DEBUG, "Done!");
}
#endif
void check_prf_update(void) {
if (!boot_bit_test(BOOT_BIT_NEW_PRF_AVAILABLE)) {
return;
}
boot_bit_clear(BOOT_BIT_NEW_PRF_AVAILABLE);
#ifndef RECOVERY_FW
prv_do_update();
#endif
}