080506ad0a
Recently commit bab55417b1 ("block: support embedded device command
line partition") introduced CONFIG_CMDLINE_PARSER. However, that name
is too generic and sounds like it enables/disables generic kernel boot
arg processing, when it really is block specific.
Before this option becomes a part of a full/final release, add the BLK_
prefix to it so that it is clear in absence of any other context that it
is block specific.
In addition, fix up the following less critical items:
- help text was not really at all helpful.
- index file for Documentation was not updated
- add the new arg to Documentation/kernel-parameters.txt
- clarify wording in source comments
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Cai Zhiyong <caizhiyong@huawei.com>
Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
40 lines
1.3 KiB
Plaintext
40 lines
1.3 KiB
Plaintext
Embedded device command line partition parsing
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=====================================================================
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Support for reading the block device partition table from the command line.
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It is typically used for fixed block (eMMC) embedded devices.
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It has no MBR, so saves storage space. Bootloader can be easily accessed
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by absolute address of data on the block device.
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Users can easily change the partition.
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The format for the command line is just like mtdparts:
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blkdevparts=<blkdev-def>[;<blkdev-def>]
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<blkdev-def> := <blkdev-id>:<partdef>[,<partdef>]
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<partdef> := <size>[@<offset>](part-name)
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<blkdev-id>
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block device disk name, embedded device used fixed block device,
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it's disk name also fixed. such as: mmcblk0, mmcblk1, mmcblk0boot0.
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<size>
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partition size, in bytes, such as: 512, 1m, 1G.
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<offset>
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partition start address, in bytes.
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(part-name)
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partition name, kernel send uevent with "PARTNAME". application can create
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a link to block device partition with the name "PARTNAME".
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user space application can access partition by partition name.
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Example:
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eMMC disk name is "mmcblk0" and "mmcblk0boot0"
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bootargs:
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'blkdevparts=mmcblk0:1G(data0),1G(data1),-;mmcblk0boot0:1m(boot),-(kernel)'
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dmesg:
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mmcblk0: p1(data0) p2(data1) p3()
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mmcblk0boot0: p1(boot) p2(kernel)
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