projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / blame
| Commit | Line | Data |
|---|---|---|
| 080506ad | 1 | Embedded device command line partition parsing |
| bab55417 CZ |
2 | ===================================================================== |
| 3 | ||
| 080506ad PG |
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 | |
| bab55417 CZ |
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) |