uboot通过kernel command line 动态分区 CONFIG_MTD_CMDLINE_PARTS

[Bean Huo]

之前一直用静态的来给flash分区，没有用过physmap，有一个疑问，不明白，通过命令转进去的mtdid是怎么确定的，我看有的是用fc000000-flash有的是用physmap-flash.0,如下：

General informations

The Linux kernel configuration item CONFIG_MTD_CMDLINE_PARTS has multiple definitions:

drivers/mtd/Kconfig

The configuration item CONFIG_MTD_CMDLINE_PARTS:

prompt: Command line partition table parsing
type: tristate
depends on: CONFIG_MTD_PARTITIONS = "y" && CONFIG_MTD = "y"
defined in drivers/mtd/Kconfig
found in Linux Kernels: from 2.6.0 release still available on 2.6.39 release
module created: cmdlinepart
Help text
Allow generic configuration of the MTD partition tables via the kernel command line. Multiple flash resources are supported for hardware where different kinds of flash memory are available.

You will still need the parsing functions to be called by the driver for your particular device. It won't happen automatically. The SA1100 map driver (CONFIG_MTD_SA1100) has an option for this, for example.

The format for the command line is as follows:

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)

Due to the way Linux handles the command line, no spaces are allowed in the partition definition（中间不能有空格）, including mtd id's and partition names.

Examples:

1 flash resource (mtd-id "sa1100"), with 1 single writable partition: mtdparts=sa1100:-

Same flash, but 2 named partitions, the first one being read-only: mtdparts=sa1100:256k(ARMboot)ro,-(root)

If unsure, say 'N'.



1. uboot $mtdparts 和 linux /dev/mtd* 的联系
比如：
uboot:# setenv mtdparts 'mtdparts=nx_2016:1408k@0k(boot),128k@1408k(env),-(extra);nx_2017:16m(k0),16m(k1),-(nandextra)'
linux:# cat /proc/mtd
dev: size erasesize name
mtd0: 00160000 00010000 "boot"
mtd1: 00020000 00010000 "env"
mtd2: 00280000 00010000 "extra"
mtd3: 00400000 00010000 "nx_2016"
mtd4: 04000000 00004000 "nx_2017"
mtd5: 01000000 00004000 "k0"
mtd6: 01000000 00004000 "k1"
mtd7: 02000000 00004000 "nandextra"

[Bean Huo]

刚找到原因了，必须和physmap.c的platform的名子相等。呵呵