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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