能帮我写一份fal_flash_stm32f1.c吗?

当然可以，以下是一个简单的fal_flash_stm32f1.c示例代码，你可以根据自己的具体需求进行修改和优化：

#include "fal.h"
#include "fal_flash_stm32f1.h"

/* 定义fal_flash_stm32f1设备结构体 */
static struct fal_flash_dev stm32f1_flash = {
    .name = "stm32f1_flash",
    .addr_start = 0x08000000, /* flash起始地址 */
    .addr_end = 0x080FFFFF, /* flash结束地址 */
    .page_size = FLASH_PAGE_SIZE, /* flash每页大小 */
    .ops = {
        .init = fal_flash_stm32f1_init,
        .read = fal_flash_stm32f1_read,
        .write = fal_flash_stm32f1_write,
        .erase = fal_flash_stm32f1_erase,
    },
};

/* fal_flash_stm32f1初始化函数 */
int fal_flash_stm32f1_init(void)
{
    /* stm32f1_flash设备初始化 */
    return fal_flash_dev_register(&stm32f1_flash);
}

/* fal_flash_stm32f1读取函数 */
int fal_flash_stm32f1_read(fal_flash_t dev, uint32_t offset, void *buf, size_t size)
{
    uint32_t addr = dev->addr_start + offset;
    memcpy(buf, (const void *)addr, size);
    return 0;
}

/* fal_flash_stm32f1写入函数 */
int fal_flash_stm32f1_write(fal_flash_t dev, uint32_t offset, const void *buf, size_t size)
{
    uint32_t addr = dev->addr_start + offset;
    uint32_t end_addr = addr + size;
    uint32_t page_addr = addr & ~(dev->page_size - 1);
    uint32_t end_page_addr = end_addr & ~(dev->page_size - 1);
    uint32_t page_offset = addr - page_addr;
    uint32_t *page_buf = (uint32_t *)fal_cache_alloc(dev->page_size);

    /* 判断写入的数据是否跨页 */
    if (page_addr == end_page_addr) {
        /* 不跨页，直接写入数据 */
        memcpy((void *)page_buf, (const void *)page_addr, dev->page_size);
        memcpy((void *)((uint32_t)page_buf + page_offset), buf, size);
        HAL_FLASH_Unlock();
        for (uint32_t i = 0; i < dev->page_size / 4; i++) {
            HAL_FLASH_Program(
                FLASH_TYPEPROGRAM_WORD,
                page_addr + i * 4,
                *(page_buf + i)
            );
        }
        HAL_FLASH_Lock();
    } else {
        /* 跨页，需要分别处理 */
        uint32_t first_size = dev->page_size - page_offset;
        memcpy((void *)page_buf, (const void *)page_addr, dev->page_size);
        memcpy((void *)((uint32_t)page_buf + page_offset), buf, first_size);
        HAL_FLASH_Unlock();
        for (uint32_t i = 0; i < dev->page_size / 4; i++) {
            HAL_FLASH_Program(
                FLASH_TYPEPROGRAM_WORD,
                page_addr + i * 4,
                *(page_buf + i)
            );
        }
        HAL_FLASH_Lock();
        for (uint32_t i = 0; i < (end_addr - end_page_addr) / 4; i++) {
            HAL_FLASH_Unlock();
            HAL_FLASH_Program(
                FLASH_TYPEPROGRAM_WORD,
                end_page_addr + i * 4,
                *((uint32_t *)buf + first_size / 4 + i)
            );
            HAL_FLASH_Lock();
        }
    }

    fal_cache_free(page_buf);
    return 0;
}

/* fal_flash_stm32f1擦除函数 */
int fal_flash_stm32f1_erase(fal_flash_t dev, uint32_t offset, size_t size)
{
    uint32_t addr = dev->addr_start + offset;
    uint32_t end_addr = addr + size;
    uint32_t page_addr = addr & ~(dev->page_size - 1);
    uint32_t end_page_addr = end_addr & ~(dev->page_size - 1);

    /* 判断擦除的数据是否跨页 */
    if (page_addr == end_page_addr) {
        /* 不跨页，直接擦除 */
        HAL_FLASH_Unlock();
        FLASH_ErasePage(page_addr);
        HAL_FLASH_Lock();
    } else {
        /* 跨页，需要分别处理 */
        HAL_FLASH_Unlock();
        FLASH_ErasePage(page_addr);
        HAL_FLASH_Lock();
        for (uint32_t addr = page_addr + dev->page_size; addr < end_page_addr; addr += dev->page_size) {
            HAL_FLASH_Unlock();
            FLASH_ErasePage(addr);
            HAL_FLASH_Lock();
        }
        HAL_FLASH_Unlock();
        FLASH_ErasePage(end_page_addr);
        HAL_FLASH_Lock();
    }

    return 0;
}