uboot支持ubi和ubifs遇到的问题
uboot version 2012.10
nand type：Micron MT29F16G08CBACA
一、执行ubi part kernel时报错-12
Creating 1 MTD partitions on "nand0":
0x000004200000-0x00001e200000 : "mtd=3"
UBI: attaching mtd1 to ubi0
UBI warning: io_init: EC and VID headers are in thesame minimal I/O unit, switch to read-only mode
UBI: physical eraseblock size: 1048576 bytes (1024KiB)
UBI: logical eraseblock size: 1044480 bytes
UBI: smallest flash I/O unit: 4096
UBI: VID header offset: 2048 (aligned 0)
UBI: data offset: 4096
UBI error: ubi_init: cannot attach mtd1
UBIerror: ubi_init: UBI error: cannot initialize UBI, error -12
UBI init error 12
Error, no UBI device/partition selected!
网上一般都是说将CONFIG_SYS_MALLOC_LEN，增大到1M(1024*1024)。但我修改后同样报错
找到源码中报错的地方(/drivers/mtd/ubi/build.cubi_attach_mtd_dev函数)
err = -ENOMEM;
ubi->peb_buf1 = vmalloc(ubi->peb_size);
if (!ubi->peb_buf1)
goto out_free;
ubi->peb_buf2 = vmalloc(ubi->peb_size);
if (!ubi->peb_buf2)
goto out_free;
malloc大小为ubi->peb_size，经过查找最终是在(/driver/mtd/nand/nand_base.cnand_get_flash_type函数)
/* Calc blocksize */
mtd->erasesize = (128 * 1024) <<
(((extid >> 1) & 0x04) | (extid &0x03));
实际该值就是物理擦出块大小，通过芯片ID获取芯片类型，查看手册
该值为1024KB，那么问题就来了，CONFIG_SYS_MALLOC_LEN设置成1M，现在一次malloc的大小也是1M，连续两次malloc就会报错了，所以当nand芯片的块大小大于等于1M时，CONFIG_SYS_MALLOC_LEN就应该相应增大，我设置成4M了
三、执行 ubifsmount kernel报错-19
UBIFS error (pid 0): ubifs_get_sb: cannot open"ubi:kernel1", error -19
UBIFS error (pid 0): ubifs_mount: Error readingsuperblock on volume 'ubi:kernel1' errno=-19!
这应该是制作kernel镜像时mkfs.ubifs参数的问题了（都是跟nand相关的参数）
再次介绍mkfs.ubifs的用法
Usage: mkfs.ubifs [OPTIONS] target
Make a UBIFS file system image from an existingdirectory tree
Examples:
Build file system from directory /opt/img, writtingthe result in the ubifs.img file
mkfs.ubifs-m 512 -e 128KiB -c 100 -r /opt/img ubifs.img
The same, but writting directly to an UBI volume
mkfs.ubifs-r /opt/img /dev/ubi0_0
Creating an empty UBIFS filesystem on an UBIvolume
mkfs.ubifs/dev/ubi0_0
Options:
-r, -d, --root=DIR buildfile system from directory DIR
-m, --min-io-size=SIZE minimum I/O unit size，最小输入输出大小
-e, --leb-size=SIZE logical erase block size逻辑可擦出块大小
-c, --max-leb-cnt=COUNT maximumlogical erase block count最大逻辑可擦出块数目
-o, --output=FILE output to FILE输出文件名
-j, --jrn-size=SIZE journal size
-R, --reserved=SIZE howmuch space should be reserved for the super-user
-x, --compr=TYPE compression type - "lzo","favor_lzo", "zlib" or
"none"(default: "lzo")
-X, --favor-percent may only be used with favor LZO compressionand defines
howmany percent better zlib should compress to make
mkfs.ubifsuse zlib instead of LZO (default 20%)
-f, --fanout=NUM fanout NUM (default:8)
-F, --space-fixup file-system free space has tobe fixed up on first moun
(requireskernel version 3.0 or greater)
-k, --keyhash=TYPE key hash type - "r5" or"test" (default: "r5")
-p, --orph-lebs=COUNT count oferase blocks for orphans (default: 1)
-D, --devtable=FILE usedevice table FILE
-U, --squash-uids squash owners making all filesowned by root
-l, --log-lebs=COUNT count oferase blocks for the log (used only for debugging)
-v, --verbose verboseoperation
-V, --version displayversion information
-g, --debug=LEVEL display debug information (0 -none, 1 - statistics, 2 - files, 3 - more details)
-h, --help displaythis help text
例：
mkfs.ubifs -x lzo -m 2KiB -e 124KiB -c 720 -osystem_ubifs.img -d $path_to_system
压缩格式为lzo
-m最小输入输出大小为2KiB(2048bytes)，一般为页大小
-e逻辑可擦除块大小为124KiB=(每块的页数-2)*页大小=（64-2）*2KiB=124KiB
-c最多逻辑可擦除块数目为720(720*128KiB=90MiB),这个可根据ubi volume来设置，实际上是设置此卷的最大容量。
按照例子，
-m参数应该是4096
-e参数应该是blocksize-2*pagesize=1M-2*4k=1040384（一般这2个page是用来存放ubi相关数据的，所以不能擦除）
-c参数应该是存放这个文件的分区大小有多少个块，我分了kernel分区为32M，那么这个值就是32M/1M= 32