Based on kernel version 4.16.1. Page generated on 2018-04-09 11:52 EST.
1 Embedded device command line partition parsing 2 ===================================================================== 3 4 Support for reading the block device partition table from the command line. 5 It is typically used for fixed block (eMMC) embedded devices. 6 It has no MBR, so saves storage space. Bootloader can be easily accessed 7 by absolute address of data on the block device. 8 Users can easily change the partition. 9 10 The format for the command line is just like mtdparts: 11 12 blkdevparts=<blkdev-def>[;<blkdev-def>] 13 <blkdev-def> := <blkdev-id>:<partdef>[,<partdef>] 14 <partdef> := <size>[@<offset>](part-name) 15 16 <blkdev-id> 17 block device disk name, embedded device used fixed block device, 18 it's disk name also fixed. such as: mmcblk0, mmcblk1, mmcblk0boot0. 19 20 <size> 21 partition size, in bytes, such as: 512, 1m, 1G. 22 23 <offset> 24 partition start address, in bytes. 25 26 (part-name) 27 partition name, kernel send uevent with "PARTNAME". application can create 28 a link to block device partition with the name "PARTNAME". 29 user space application can access partition by partition name. 30 31 Example: 32 eMMC disk name is "mmcblk0" and "mmcblk0boot0" 33 34 bootargs: 35 'blkdevparts=mmcblk0:1G(data0),1G(data1),-;mmcblk0boot0:1m(boot),-(kernel)' 36 37 dmesg: 38 mmcblk0: p1(data0) p2(data1) p3() 39 mmcblk0boot0: p1(boot) p2(kernel)