RT-Thread-【NXP-MCXA153】RTT MTD驱动添加RT-Thread问答社区

【NXP-MCXA153】RTT MTD驱动添加

发布于 2024-07-24 09:19:33 浏览：379 订阅该版

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## NOR flash 
一般在MB级别，常见的如 8MB 16MB 等，不过我此章节的驱动是利用片上flash ，此开发板的A153有128KB的片上flash，尝试将其中的512字节取出然后作为存储数据
## MTD MOR 层级结构

![1.png](https://oss-club.rt-thread.org/uploads/20240724/0a40725c06a338a9b1f388cbe4ff52fb.png)
MTD设备驱动框架是在mtd_nand.c文件中，其基本功能是：

- 向文件系统提供 rt_mtd_nor_read, rt_mtd_nor_write，rt_mtd_nor_read_id等接口
- 向底层提供 rt_mtd_nor_driver_ops 成员就是上述接口地址，俺就要实现这些功能
- 注册接口 rt_mtd_nor_device

flash的底层操作，目前只用内部flash，读写操作就是调用NXP的底层接口了
## 代码实现
### 创建MTD NOR 设备
```c
struct rt_mtd_nor_device
{
    struct rt_device parent;

rt_uint32_t block_size;         /* The Block size in the flash */
    rt_uint32_t block_start;        /* The start of available block*/
    rt_uint32_t block_end;          /* The end of available block */

/* operations interface */
    const struct rt_mtd_nor_driver_ops* ops;
};
```
### 需要实现的接口
```c
struct rt_mtd_nor_driver_ops
{
    rt_err_t (*read_id) (struct rt_mtd_nor_device* device);

rt_ssize_t (*read)    (struct rt_mtd_nor_device* device, rt_off_t offset, rt_uint8_t* data, rt_size_t length);
    rt_ssize_t (*write)   (struct rt_mtd_nor_device* device, rt_off_t offset, const rt_uint8_t* data, rt_size_t length);

rt_err_t (*erase_block)(struct rt_mtd_nor_device* device, rt_off_t offset, rt_size_t length);
};
```
#### read
```c
/**
 * device MTD nor 设备句柄
 * offset 偏移量
 * data 读取的数据
 * length 读取的数据长度
 */
rt_ssize_t nxp_chipflash_read   (struct rt_mtd_nor_device* device, rt_off_t offset, rt_uint8_t* data, rt_size_t length)
{
    for(int i = 0; i < length; i++)
    {
        *(data + i) = *(volatile rt_uint8_t *)(mtd.destAdrss + offset + i);
    }
    return length;
}
```
#### write
```c
/**
 * device MTD nor 设备句柄
 * offset 偏移量
 * data 读取的数据
 * length 读取的数据长度
 */
rt_ssize_t nxp_chipflash_write   (struct rt_mtd_nor_device* device, rt_off_t offset, const rt_uint8_t* data, rt_size_t length)
{
    rt_kprintf("%s %d\n","nxp_chipflash_write", *data);
    int32_t status = FLASH_API->flash_program_page(&mtd.s_flashDriver, mtd.destAdrss + offset, (uint8_t *)data, length);
    if (status != kStatus_Success)
    {
        return 0;
    }
    return length;
}
```
#### erase_block
```c
/**
 * device MTD nor 设备句柄
 * offset 偏移量
 * length 长度
 */
rt_err_t nxp_chipflash_erase_block (struct rt_mtd_nor_device* device, rt_off_t offset, rt_size_t length)
{
    FLASH_API->flash_erase_sector(&mtd.s_flashDriver, mtd.destAdrss, mtd.pflashSectorSize, kFLASH_ApiEraseKey);
    return RT_EOK;
}
```
#### 初始化
```c
rt_err_t rt_onchipflash_init(const char* mtd_name)
{
    
    memset(&mtd.s_flashDriver, 0, sizeof(flash_config_t));
    if (FLASH_API->flash_init(&mtd.s_flashDriver) != kStatus_Success)
    {
        return RT_ERROR;
    }
    //获取参数
    FLASH_API->flash_get_property(&mtd.s_flashDriver, kFLASH_PropertyPflashBlockBaseAddr, &mtd.pflashBlockBase);
    FLASH_API->flash_get_property(&mtd.s_flashDriver, kFLASH_PropertyPflashSectorSize, &mtd.pflashSectorSize);
    FLASH_API->flash_get_property(&mtd.s_flashDriver, kFLASH_PropertyPflashTotalSize, &mtd.pflashTotalSize);
    FLASH_API->flash_get_property(&mtd.s_flashDriver, kFLASH_PropertyPflashPageSize, &mtd.PflashPageSize);
    //记录flash地址数据 
    //flsh基地址+ flash中大小 - 数量* 扇区大小
    mtd.destAdrss = mtd.pflashBlockBase + (mtd.pflashTotalSize - (SECTOR_INDEX_FROM_END) * mtd.pflashSectorSize);
    int32_t status = FLASH_API->flash_erase_sector(&mtd.s_flashDriver, mtd.destAdrss, mtd.pflashSectorSize, kFLASH_ApiEraseKey);
    if (status != kStatus_Success)
    {
        return RT_ERROR;
    }
    mtd.mtd_device.block_start = 512;
    mtd.mtd_device.block_start = 0;
    mtd.mtd_device.ops = &mcx_mtd_chipflashops;
    rt_mtd_nor_register_device(mtd_name, &(mtd.mtd_device));
    return RT_EOK;
}
```
### 实验代码
```c
rt_onchipflash_init("mflash");
rt_onchipflash_init("mflash");
static rt_device_t mtd = RT_NULL;
mtd = rt_device_find("mflash");
if(!mtd)
    rt_kprintf("rt find device failed.\n");
else
    rt_kprintf("rt find device ok.\n");
rt_uint8_t number = 0x22;
rt_mtd_nor_write((struct rt_mtd_nor_device *)mtd, 0, &number, 1);
rt_uint8_t read = 0;
rt_mtd_nor_read((struct rt_mtd_nor_device *)mtd, 0, &read, 1);
rt_kprintf("rt mtd device read%d\n", read);
```
### 结果

![2.png](https://oss-club.rt-thread.org/uploads/20240724/52b7bbab1be91283f432d4f41e3c9385.png)
## 总结

- 操作FLASH_API 的时候需要更新 SDK 库
- 由于没外部nor flash就使用了内部的，其实就是读写操作而已，后面学习文件系统的操作，加油