数据结构设计

SDMC 数据类型及其结构描述如下：

struct aic_sdmc_host：属于 HAL 层接口，定义了 SDMC 控制器管理信息。
```
struct aic_sdmc_host {
    volatile void *base;
    u32 is_sdio;
    u32 fifoth_val;
};
```
struct aic_sdmc_idma_desc：属于 HAL 层接口，记录了 SDMC 控制器内部 DMA 访问的描述符。
```
struct aic_sdmc_idma_desc {
    u32 flags;
    u32 cnt;
    u32 addr;
    u32 next_addr;
} __aligned(8);
```

struct aic_sdmc：

RT-Thread：属于 Driver 层的内部接口，用于记录 SDMC 控制器的管理信息

struct aic_sdmc {
    struct rt_mmcsd_host *rthost;
    struct rt_mmcsd_req *req;
    struct rt_mmcsd_cmd *cmd;
    struct aic_sdmc_host host;

    rt_uint32_t *buf;
    u32 clk;
    u32 irq;
    u32 index;

    unsigned int quirks;
    unsigned int caps;
    unsigned int version;
    unsigned int clock;
    unsigned int sclk_rate;
    unsigned int div;
    int buswidth;
    int ddr_mode;

    /* use fifo mode to read and write data */
    int fifo_mode;

    struct aic_sdmc_pdata *pdata;
};

Baremetal：属于 Baremetal Driver 层的内部接口，用于记录 SDMC 控制器的管理信息

struct aic_sdmc {
    struct aic_sdmc_dev *dev;
    struct aic_sdmc_cmd *cmd;
    struct aic_sdmc_data *data;
    struct aic_sdmc_host host;

    u32 *buf;
    u32 clk;
    u32 irq;
    u32 index;

    unsigned int quirks;
    unsigned int caps;
    unsigned int version;
    unsigned int clock;
    unsigned int sclk_rate;
    unsigned int div;
    int buswidth;
    int ddr_mode;

    /* use fifo mode to read and write data */
    int fifo_mode;

    struct aic_sdmc_pdata *pdata;
};