AM335X修改nand分区大小或增加新分区

开发环境：
Ubuntu16.04 + arm-linux-gnueabihf-gcc（4.7.3）
核心板：AM335X-A8
内核版本： Linux version 3.2.0

  原先使用的是1G Nand Flash，后来发现有很多剩余，于是就砍成了512M。所以得改uboot改内核。
  上家公司使用的是海思SDK，海思SDK做的非常好，只需要配置一下uboot的启动参数即可，如（setenv bootargs8 'mem=260M console=ttyAMA0,115200 root=/dev/mtdblock2 rootfstype=squashfs   mtdparts=hi_sfc:512K(boot),3584K(kernel),3584K(rootfs),
19520K(app)';）。但是TI的不行，没对比就没伤害，好了言归正传，下面说说具体如何配置。

原有分区：
root@iBRK:~# cat /proc/mtd
dev:   size  erasesize  name
mtd0: 00020000 00020000 "SPL"
mtd1: 00200000 00020000 "U-Boot"
mtd2: 00020000 00020000 "U-Boot Env"
mtd3: 00500000 00020000 "Kernel"
mtd4: 08000000 00020000 "File System"
mtd5: 10000000 00020000 "UsrLocal"
mtd6: 078c0000 00020000 "WorkData"

在已有的基础上增加一个4M的para分区用于保存APP参数。

一、修改uboot环境参数 TI的环境变量和常用参数配置的文件位于uboot/include/configs/am335x_evm.h
1.修改DFU_ALT_INFO_NAND宏，增加新的分区

#if 0
#define DFU_ALT_INFO_NAND \
    "SPL part 0 1;" \
    "u-boot part 0 2;" \
    "kernel part 0 4;" \
    "rootfs part 0 5;" \
    "local part 0 6;" \
    "data part 0 7"
#else
#define DFU_ALT_INFO_NAND \
    "SPL part 0 1;" \
    "u-boot part 0 2;" \
    "kernel part 0 4;" \
    "rootfs part 0 5;" \
    "local part 0 6;" \
    "data part 0 7;" \
    "para part 0 8"    /* 新增 */
#endif

2.修改MTDPARTS_DEFAULT宏，定义分区大小，其中下面最后的-表示使用剩余容量

#if 0
#define MTDPARTS_DEFAULT        "mtdparts=omap2-nand.0:128k(SPL)," \
                    "2m(u-boot)," \
                    "128k(u-boot-env),5m(kernel),128m(rootfs)," \
                    "256m(local),-(data)"
#else
#define MTDPARTS_DEFAULT        "mtdparts=omap2-nand.0:128k(SPL)," \
                    "2m(u-boot)," \
                    "128k(u-boot-env),5m(kernel),128m(rootfs)," \
                    "256m(local),,116(data),-(para),"
#endif

二、修改kernel配置项
内核的分区配置信息位于kernel/arch/arm，TI平台的AM335X相关配置位于kernel/arch/arm/mach-omap2/文件夹，找到对应板子使用的文件，如我这边使用的是board-am335x_wld.c，修改分区结构体am335x_nand_partition

点击(此处)折叠或打开
						
					
					
						/* NAND partition information */
static struct mtd_partition am335x_nand_partitions[] = {
/* All the partition sizes are listed in terms of NAND block size */
    {
                .name = "SPL",
                .offset = 0, /* Offset = 0x0 */
                .size = SZ_128K, /* size = 128K */
        },
        {
                .name = "U-Boot",
                .offset = MTDPART_OFS_APPEND, /* offset = 0x20000 */
                .size = 16*SZ_128K, /* size = 2M */
        },
        {
                .name = "U-Boot Env",
                .offset = MTDPART_OFS_APPEND, /* offset = 0x220000 */
                .size = SZ_128K, /* size = 128K */
        },
        {
                .name = "Kernel",
                .offset = MTDPART_OFS_APPEND, /* Offset = 0x240000 */
                .size = 40 * SZ_128K, /* size = 5M */
        },
        {
                .name = "File System",
                .offset = MTDPART_OFS_APPEND, /* Offset = 0x740000 */
                .size = SZ_128M, /* size = 128M */
        },
        {
                .name = "UsrLocal",
                .offset = MTDPART_OFS_APPEND, /* Offset = 0x8740000 */
                .size = SZ_256M, /* size = 256M */
        },
        {
                .name = "WorkData",
                .offset = MTDPART_OFS_APPEND, /* Offset = 0x18740000 */
                .size = SZ_4M * 29, /* size = 116M */
        },
        {
                .name = "para", /* 新增 */
                .offset = MTDPART_OFS_APPEND, /* Offset = 0x1FC0 0000 */
                .size = MTDPART_SIZ_FULL, /* size = 4M */
        },

};

然后重编uboot和kernel，烧录进去即可。
启动后再查看分区情况：
root@iBRK:~# cat /proc/mtd
dev:   size  erasesize  name
mtd0: 00020000 00020000 "SPL"
mtd1: 00200000 00020000 "U-Boot"
mtd2: 00020000 00020000 "U-Boot Env"
mtd3: 00500000 00020000 "Kernel"
mtd4: 08000000 00020000 "File System"
mtd5: 10000000 00020000 "UsrLocal"
mtd6: 07400000 00020000 "WorkData"
mtd7: 004c0000 00020000 "para"