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I:修改mtd block partition size

1.修改kernel 原始碼

arch/arm/mach-xx/devices.c

static struct mtd_partition nand_partitions[] = {

{

.name = "Boot Area",

.offset = 0x40000, //0x40000 - 0x80000 //0.25M

.size = 256 * 1024,

},

{

.name = "Diag Area",

.offset = MTDPART_OFS_APPEND, //0x80000 - 0x180000 //1M

.size = 1 * 1024 * 1024,

},

{

.name = "Kernel",

.offset = MTDPART_OFS_APPEND, //0x180000 - 0x1500000 //19.5M

.size = 19 * 1024 * 1024 + 512 * 1024,

},

{

.name = "Root Filesystem",

.offset = MTDPART_OFS_APPEND, //0x1500000 - 0x3500000 - 32M

.size = 32 * 1024 * 1024,//32

},

{

.name = "opt",

.offset = MTDPART_OFS_APPEND, //0x3500000 - 0x6d00000 -56M

.size = 56 * 1024 * 1024 ,

},

{

.name = "demo",

.offset = MTDPART_OFS_APPEND, //0x6d00000 - 0x8000000 - 19M

.size = MTDPART_SIZ_FULL,

},

};

#endif

2.重開測試

Creating 6 MTD partitions on "NAND 128MiB 3,3V 8-bit":
0x00040000-0x00080000 : "Boot Area"
0x00080000-0x00180000 : "Diag Area"
0x00180000-0x01500000 : "Kernel"
0x01500000-0x03500000 : "Root Filesystem"
0x03500000-0x06d00000 : "opt"
0x06d00000-0x08000000 : "demo"

3.建立檔案系統影像檔
如下建立56M

echo "mk opt 56M"

dd if=/dev/zero of=opt56m bs=56M count=1

mke2fs -F opt56m

mkdir -p tmp

mount -o loop opt56m tmp

cd tmp

cp -a ../opt/* ./

cd ..

umount tmp

rm -r tmp

cp -f opt56m /tftpboot

4.燒錄到nand flash

setenv nopt tftp 40800000 opt56m\;nand erase 3500000 3800000\;nand write 40800000 3500000 3800000

run nopt

5.若不想修改kernel 則可使用kernle 帶參數設定mtd大小

Kernel 需支援傳遞mtd參數

Device Drivers --->
     Memory Technology Device (MTD) support --->
          [*] MTD partitioning support
          [*] Command line partition table parsing

u-boot 參數

參數格式如下

linux command mtdparts 格式：
mtdparts   = <mtddef>[;<mtddef ]
<mtddef>  := <mtd-id>:<partdef>[,<partdef>]
<partdef> := <size>[@offset][<name>][ro]
<mtd-id>  := unique id used in mapping driver/device
<size>      := standard linux memsize OR "-" to denote all
remaining space
<name>    := (NAME)

EX:

mtdparts=xx-nand: @ ( ), @ ( )

xx-nand 這個必須與kernel 一致

@ ( ) 必須都有

最後不要有 , 句號 否會出現size 太小錯誤(因逗號後面也當作一個新的分割區)

實測;
在u-boot下執行下命令

set k27mtd setenv bootargs console=ttyS0,115200n8 root=/dev/mtdblock6 rw init=/linuxrc mtdparts=xx-nand:32m@0x01500000(rootfs),56m@0x03500000(qt),19m@0x06d00000(demo)\;tftp 41000000 uImage_k27_src\;bootm 41000000

測試結果

3 cmdlinepart partitions found on MTD device xx-nand

MTD:nr_partitions = 3

MTD:new partition rootfs offset 0x1500000 size 0x2000000

MTD:new partition qt offset 0x3500000 size 0x3800000

MTD:new partition demo offset 0x6d00000 size 0x1300000

Creating 6 MTD partitions on "xx-nand":

0x00040000-0x00080000 : "Boot Area"

0x00080000-0x00180000 : "Diag Area"

0x00180000-0x01500000 : "Kernel"

0x01500000-0x03500000 : "rootfs"

0x03500000-0x06d00000 : "qt"

0x06d00000-0x08000000 : "demo"

上面的結果 因為有修改KERNEL程式碼 保留 前三塊 所以才會總共六塊

但是 s3c2410.c 並沒有把 linux command mtdparts 實做出來。
難怪怎麼測試都沒反應。

修改 linux/driver/mtd/nand/s3c2410.c：

#ifdef CONFIG_MTD_PARTITIONS

#ifdef CONFIG_MTD_CMDLINE_PARTS 
const char *part_probes[] = { "cmdlinepart", NULL };
#endif

static int s3c2410_nand_add_partition(struct s3c2410_nand_info *info,
                                      struct s3c2410_nand_mtd *mtd,
                                      struct s3c2410_nand_set *set)
{
#ifdef CONFIG_MTD_CMDLINE_PARTS 
        struct mtd_partition *partitions = NULL;
        int num_partitions = 0;
#endif
        if (set == NULL)
                return add_mtd_device(&mtd->mtd);

#ifdef CONFIG_MTD_CMDLINE_PARTS
        mtd->mtd.name = "s3c2440_nand";
        num_partitions = parse_mtd_partitions(&(mtd->mtd), part_probes, &partitions, 0);

        if(num_partitions > 0) {
            set->partitions = partitions;
            set->nr_partitions = num_partitions;
        }
#endif

        if (set->nr_partitions > 0 && set->partitions != NULL) {
             return add_mtd_partitions(&mtd->mtd, set->partitions, set->nr_partitions);
        } 
        return add_mtd_device(&mtd->mtd);
}

#else
........ }

這樣就可以在 linux command line 裡面把分區傳給 kernel
使用方法
mtdparts=s3c2440_nand:<size1>@<offset1>(<name1>),<size2>@<offset2>(<name2>)

其中 "s3c2440_nand" 要跟 mtd->mtd.name 一樣