diff options
| author | Takashi Iwai <tiwai@suse.de> | 2020-03-30 13:43:00 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2020-03-30 13:43:00 +0200 |
| commit | 3c22baeab40b2f8e75907cfd7aa69147d5343d2c (patch) | |
| tree | e8300e52242ae3a9c7bfe6089ee7125324095e27 /Documentation/admin-guide/bootconfig.rst | |
| parent | aa21c3d4b941739651e77747d2f7a20a6c1d87bc (diff) | |
| parent | 1c521d7e62262793789845989edca57dea24eb7d (diff) | |
Merge tag 'asoc-v5.7' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus
ASoC: Updates for v5.7
This is a very big update for the core since Morimoto-san has been
rather busy continuing his refactorings to clean up a lot of the cruft
that we have accumilated over the years. We've also gained several new
drivers, including initial (but still not complete) parts of the Intel
SoundWire support.
- Lots of refactorings to modernize the code from Morimoto-san.
- Conversion of SND_SOC_ALL_CODECS to use imply from Geert Uytterhoeven.
- Continued refactoring and fixing of the Intel support.
- Soundwire and more advanced clocking support for Realtek RT5682.
- Support for amlogic GX, Meson 8, Meson 8B and T9015 DAC, Broadcom
DSL/PON, Ingenic JZ4760 and JZ4770, Realtek RL6231, and TI TAS2563 and
TLV320ADCX140.
Diffstat (limited to 'Documentation/admin-guide/bootconfig.rst')
| -rw-r--r-- | Documentation/admin-guide/bootconfig.rst | 34 |
1 files changed, 31 insertions, 3 deletions
diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst index b342a6796392..cf2edcd09183 100644 --- a/Documentation/admin-guide/bootconfig.rst +++ b/Documentation/admin-guide/bootconfig.rst @@ -62,6 +62,30 @@ Or more shorter, written as following:: In both styles, same key words are automatically merged when parsing it at boot time. So you can append similar trees or key-values. +Same-key Values +--------------- + +It is prohibited that two or more values or arrays share a same-key. +For example,:: + + foo = bar, baz + foo = qux # !ERROR! we can not re-define same key + +If you want to append the value to existing key as an array member, +you can use ``+=`` operator. For example:: + + foo = bar, baz + foo += qux + +In this case, the key ``foo`` has ``bar``, ``baz`` and ``qux``. + +However, a sub-key and a value can not co-exist under a parent key. +For example, following config is NOT allowed.:: + + foo = value1 + foo.bar = value2 # !ERROR! subkey "bar" and value "value1" can NOT co-exist + + Comments -------- @@ -102,9 +126,13 @@ Boot Kernel With a Boot Config ============================== Since the boot configuration file is loaded with initrd, it will be added -to the end of the initrd (initramfs) image file. The Linux kernel decodes -the last part of the initrd image in memory to get the boot configuration -data. +to the end of the initrd (initramfs) image file with size, checksum and +12-byte magic word as below. + +[initrd][bootconfig][size(u32)][checksum(u32)][#BOOTCONFIG\n] + +The Linux kernel decodes the last part of the initrd image in memory to +get the boot configuration data. Because of this "piggyback" method, there is no need to change or update the boot loader and the kernel image itself. |
