android2.3.4----7.mtd partition的添加

原文地址：http://blog.chinaunix.net/uid-26009923-id-4067430.html

一.分区的定义
1. 定义分区信息
在arch/arm/mach-s3c64xx/mach-smdk6410.c中

struct mtd_partition ok6410_nand_part[] = {
    {
        .name        = "Bootloader",
        .offset        = 0,
        .size        = (1 * SZ_1M),
        .mask_flags    = MTD_CAP_NANDFLASH,
    },
    {
        .name        = "Kernel",
        .offset        = (1 * SZ_1M),
        .size        = (5*SZ_1M) ,
        .mask_flags    = MTD_CAP_NANDFLASH,
    },

    {
        .name        = "User",
        .offset        = (6 * SZ_1M),
        .size        = (200*SZ_1M) ,
    },
    {
        .name        = "File System",
        .offset        = MTDPART_OFS_APPEND,
        .size        = MTDPART_SIZ_FULL,
    }
};

2.将mtd_partition封装在s3c2410_nand中
在arch/arm/mach-s3c64xx/mach-smdk6410.c中

static struct s3c2410_nand_set ok6410_nand_sets[] = {
    [0] = {
        .name = "nand",
        .nr_chips = 1,
        .nr_partitions = ARRAY_SIZE(ok6410_nand_part),
        .partitions = ok6410_nand_part,
    },
};

3.将s3c2410_nand封装在s3c2410_platform_nand中
在arch/arm/mach-s3c64xx/mach-smdk6410.c中

static struct s3c2410_platform_nand ok6410_nand_info = {
    .tacls = 25,
    .twrph0 = 55,
    .twrph1 = 40,
    .nr_sets = ARRAY_SIZE(ok6410_nand_sets),
    .sets = ok6410_nand_sets,
};

4. 将定义的分区信息写入到全局变量中
在arch/arm/mach-s3c64xx/mach-smdk6410.c中

static void __init smdk6410_machine_init(void)
{
    s3c_nand_set_platdata(&ok6410_nand_info);
}

结构体的包含如下:
s3c2410_platform_nand  -->
                                        --> 
                                        -->sets:    s3c2410_nand_set -->
                                                                                       --> mtd_partition

在arch/arm/plat-samsung/dev-nand.c中

void __init s3c_nand_set_platdata(struct s3c2410_platform_nand *nand)
{
    struct s3c2410_platform_nand * npd = kmemdup(nand, sizeof(struct s3c2410_platform_nand), GFP_KERNEL);
    int size = sizeof(struct s3c2410_nand_set) * npd->nr_sets;   //nr_sets=1

    struct s3c2410_nand_set *from = npd->sets;
    struct s3c2410_nand_set *to;

    to = kmemdup(from, size, GFP_KERNEL);   //将
    npd->sets = to;

    for (int i = 0; i < npd->nr_sets; i++) {
        ret = s3c_nand_copy_set(to);
        to++;
    }
    s3c_device_nand.dev.platform_data = npd;
}

这个函数就是把以前定义的东东重新copy了一份给npd,这儿完全没有必要这么做
改成如下,简单明了

void __init s3c_nand_set_platdata(struct s3c2410_platform_nand *nand)
{
    s3c_device_nand.dev.platform_data = nand;
}

5. 分区信息在驱动中的获取

static int s3c_nand_probe(struct platform_device *pdev, enum s3c_cpu_type cpu_type)
{
    struct s3c2410_platform_nand *plat = pdev->dev.platform_data;
}

这个地方就可以通过
    plat->sets->partitions->offset,
    plat->sets->partitions->size,
    plat->sets->partitions->name
找到所对应的分区信息
6. 在驱动中的probe函数中添加partition
s3c_nand_probe
    --> add_mtd_partitions

int add_mtd_partitions(struct mtd_info *master,    const struct mtd_partition *parts, int nbparts)
{
    struct mtd_part *slave;
    uint64_t cur_offset = 0;

    for (i = 0; i < nbparts; i++) {
        slave = add_one_partition(master, parts + i, i, cur_offset);
        cur_offset = slave->offset + slave->mtd.size;
    }
    return 0;
}