spi nand flash 驱动代码

以下是一个简单的SPI NAND Flash驱动代码的示例，基于Linux内核的MTD框架：

#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/spi/spi.h>

#define SPI_NAND_CMD_READ    0x03
#define SPI_NAND_CMD_READID  0x9F
#define SPI_NAND_CMD_RESET   0xFF

#define SPI_NAND_PAGE_SIZE   2048
#define SPI_NAND_BLOCK_SIZE  (64 * 1024)
#define SPI_NAND_CHIP_SIZE   (1024 * 1024 * 8)

struct spi_nand_chip {
    struct mtd_info mtd;
    struct spi_device *spi;
    u8 *buf;
};

static int spi_nand_read_buf(struct spi_nand_chip *chip, u32 addr, u8 *buf, u32 len)
{
    u8 cmd[4];
    int ret;

    cmd[0] = SPI_NAND_CMD_READ;
    cmd[1] = addr >> 16;
    cmd[2] = addr >> 8;
    cmd[3] = addr;

    ret = spi_write_then_read(chip->spi, cmd, sizeof(cmd), buf, len);
    if (ret < 0) {
        dev_err(&chip->spi->dev, "SPI NAND read error: %d\n", ret);
        return ret;
    }

    return 0;
}

static int spi_nand_read_id(struct spi_nand_chip *chip)
{
    u8 cmd = SPI_NAND_CMD_READID;
    u8 id[5];
    int ret;

    ret = spi_write_then_read(chip->spi, &cmd, sizeof(cmd), id, sizeof(id));
    if (ret < 0) {
        dev_err(&chip->spi->dev, "SPI NAND read ID error: %d\n", ret);
        return ret;
    }

    dev_info(&chip->spi->dev, "SPI NAND ID: %02x %02x %02x %02x %02x\n",
             id[0], id[1], id[2], id[3], id[4]);

    return 0;
}

static int spi_nand_probe(struct spi_device *spi)
{
    struct spi_nand_chip *chip;
    struct mtd_info *mtd;
    int ret;

    chip = devm_kzalloc(&spi->dev, sizeof(*chip), GFP_KERNEL);
    if (!chip)
        return -ENOMEM;

    chip->buf = devm_kmalloc(&spi->dev, SPI_NAND_PAGE_SIZE, GFP_KERNEL);
    if (!chip->buf)
        return -ENOMEM;

    mtd = &chip->mtd;
    mtd->name = "spi-nand";
    mtd->type = MTD_NANDFLASH;
    mtd->flags = MTD_CAP_NANDFLASH;
    mtd->writesize = SPI_NAND_PAGE_SIZE;
    mtd->erasesize = SPI_NAND_BLOCK_SIZE;
    mtd->size = SPI_NAND_CHIP_SIZE;
    mtd->_erase = nand_erase;
    mtd->_read = nand_read;

    ret = spi_setup(spi);
    if (ret)
        return ret;

    chip->spi = spi;

    ret = spi_nand_read_id(chip);
    if (ret)
        return ret;

    return mtd_device_register(mtd, NULL, 0);
}

static int spi_nand_remove(struct spi_device *spi)
{
    struct mtd_info *mtd = spi_get_drvdata(spi);
    mtd_device_unregister(m