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Use flash_safe_execute #545

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Use flash_safe_execute #545

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27 changes: 25 additions & 2 deletions flash/program/flash_program.c
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@
#include <stdlib.h>

#include "pico/stdlib.h"
#include "pico/flash.h"
#include "hardware/flash.h"

// We're going to erase and reprogram a region 256k from the start of flash.
Expand All @@ -26,6 +27,19 @@ void print_buf(const uint8_t *buf, size_t len) {
}
}

// This function will be called when it's safe to call flash_range_erase
static void call_flash_range_erase(void *param) {
uint32_t offset = (uint32_t)param;
flash_range_erase(offset, FLASH_SECTOR_SIZE);
}

// This function will be called when it's safe to call flash_range_program
static void call_flash_range_program(void *param) {
uint32_t offset = ((uintptr_t*)param)[0];
const uint8_t *data = (const uint8_t *)((uintptr_t*)param)[1];
flash_range_program(offset, data, FLASH_PAGE_SIZE);
}

int main() {
stdio_init_all();
uint8_t random_data[FLASH_PAGE_SIZE];
Expand All @@ -37,12 +51,21 @@ int main() {

// Note that a whole number of sectors must be erased at a time.
printf("\nErasing target region...\n");
flash_range_erase(FLASH_TARGET_OFFSET, FLASH_SECTOR_SIZE);

// Flash is "execute in place" and so will be in use when any code runs, e.g. an interrupt handler or code running on a different core
// Calling flash_range_erase or flash_range_program at the same time as flash is running code would cause a crash.
// flash_safe_execute disables interrupts and tries to cooperate with the other core to ensure flash is not in use
// See the documentation for flash_safe_execute and its assumptions and limitations
int rc = flash_safe_execute(call_flash_range_erase, (void*)FLASH_TARGET_OFFSET, UINT32_MAX);
hard_assert(rc == PICO_OK);

printf("Done. Read back target region:\n");
print_buf(flash_target_contents, FLASH_PAGE_SIZE);

printf("\nProgramming target region...\n");
flash_range_program(FLASH_TARGET_OFFSET, random_data, FLASH_PAGE_SIZE);
uintptr_t params[] = { FLASH_TARGET_OFFSET, (uintptr_t)random_data};
rc = flash_safe_execute(call_flash_range_program, params, UINT32_MAX);
hard_assert(rc == PICO_OK);
printf("Done. Read back target region:\n");
print_buf(flash_target_contents, FLASH_PAGE_SIZE);

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