mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-04 18:41:03 +00:00
51 lines
2 KiB
Text
51 lines
2 KiB
Text
|
To enable this feature just define CONFIG_HWCONFIG in your board
|
||
|
|
config file.
|
||
|
|
|
||
|
|
This implements a simple hwconfig infrastructure: an
|
||
|
|
interface for software knobs to control hardware.
|
||
|
|
|
||
|
|
This a is very simple implementation, i.e. it is implemented
|
||
|
|
via the `hwconfig' environment variable. Later we could write
|
||
|
|
some "hwconfig <enable|disable|list>" commands, ncurses
|
||
|
|
interface for Award BIOS-like interface, and frame-buffer
|
||
|
|
interface for AMI GUI[1] BIOS-like interface with mouse
|
||
|
|
support[2].
|
||
|
|
|
||
|
|
Current implementation details/limitations:
|
||
|
|
|
||
|
|
1. Doesn't support options dependencies and mutual exclusion.
|
||
|
|
We can implement this by integrating apt-get[3] into Das
|
||
|
|
U-Boot. But I haven't bothered yet.
|
||
|
|
|
||
|
|
2. Since we don't implement a hwconfig command, i.e. we're working
|
||
|
|
with the environement directly, there is no way to tell that
|
||
|
|
toggling a particular option will need a reboot to take
|
||
|
|
effect. So, for now it's advised to always reboot the
|
||
|
|
target after modifying the hwconfig variable.
|
||
|
|
|
||
|
|
3. We support hwconfig options with arguments. For example,
|
||
|
|
|
||
|
|
set hwconfig "dr_usb:mode=peripheral,phy_type=ulpi"
|
||
|
|
|
||
|
|
This selects three hwconfig options:
|
||
|
|
1. dr_usb - enable Dual-Role USB controller;
|
||
|
|
2. dr_usb_mode:peripheral - USB in Function mode;
|
||
|
|
3. dr_usb_phy_type:ulpi - USB should work with ULPI PHYs.
|
||
|
|
|
||
|
|
The purpose of this simple implementation is to refine the
|
||
|
|
internal API and then we can continue improving the user
|
||
|
|
experience by adding more mature interfaces, like a hwconfig
|
||
|
|
command with bells and whistles. Or not adding, if we feel
|
||
|
|
that the current interface fits people's needs.
|
||
|
|
|
||
|
|
[1] http://en.wikipedia.org/wiki/American_Megatrends
|
||
|
|
[2] Regarding ncurses and GUI with mouse support -- I'm just
|
||
|
|
kidding.
|
||
|
|
[3] The comment regarding apt-get is also a joke, meaning that
|
||
|
|
dependency tracking could be non-trivial. For example, for
|
||
|
|
enabling HW feature X we may need to disable Y, and turn Z
|
||
|
|
into reduced mode (like RMII-only interface for ethernet,
|
||
|
|
no MII).
|
||
|
|
|
||
|
|
It's quite trivial to implement simple cases though.
|