From: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Make the description of the kernel command line option "blkdevparts"
a bit more flowing and readable.
Fix a few typos.
Add the optional <size> and <offset> suffixes.
Note that size can be "-" to indicate all of the remaining space.
Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Cai Zhiyong <caizhiyong@xxxxxxxxxx>
---
Should the "ro" and "lk" flags options be described?
Documentation/block/cmdline-partition.txt | 21 +++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
--- linux-next-20180504.orig/Documentation/block/cmdline-partition.txt
+++ linux-next-20180504/Documentation/block/cmdline-partition.txt
@@ -1,7 +1,9 @@
Embedded device command line partition parsing
=====================================================================
-Support for reading the block device partition table from the command line.
+The "blkdevparts" command line option adds support for reading the
+block device partition table from the kernel command line.
+
It is typically used for fixed block (eMMC) embedded devices.
It has no MBR, so saves storage space. Bootloader can be easily accessed
by absolute address of data on the block device.
@@ -14,22 +16,27 @@ blkdevparts=<blkdev-def>[;<blkdev-def>]
<partdef> := <size>[@<offset>](part-name)
<blkdev-id>
- block device disk name, embedded device used fixed block device,
- it's disk name also fixed. such as: mmcblk0, mmcblk1, mmcblk0boot0.
+ block device disk name. Embedded device uses fixed block device.
+ Its disk name is also fixed, such as: mmcblk0, mmcblk1, mmcblk0boot0.
<size>
partition size, in bytes, such as: 512, 1m, 1G.
+ size may contain an optional suffix of (upper or lower case):
+ K, M, G, T, P, E.
+ "-" is used to denote all remaining space.
<offset>
partition start address, in bytes.
+ offset may contain an optional suffix of (upper or lower case):
+ K, M, G, T, P, E.
(part-name)
- partition name, kernel send uevent with "PARTNAME". application can create
- a link to block device partition with the name "PARTNAME".
- user space application can access partition by partition name.
+ partition name. Kernel sends uevent with "PARTNAME". Application can
+ create a link to block device partition with the name "PARTNAME".
+ User space application can access partition by partition name.
Example:
- eMMC disk name is "mmcblk0" and "mmcblk0boot0"
+ eMMC disk names are "mmcblk0" and "mmcblk0boot0".
bootargs:
'blkdevparts=mmcblk0:1G(data0),1G(data1),-;mmcblk0boot0:1m(boot),-(kernel)'
