projects / u-boot.git / blame
| Commit | Line | Data |
|---|---|---|
| ab68f4dd HS |
1 | This implements a simple hwconfig infrastructure: an |
| 2 | interface for software knobs to control hardware. | |
| 3 | ||
| 4 | This a is very simple implementation, i.e. it is implemented | |
| 5 | via the `hwconfig' environment variable. Later we could write | |
| 6 | some "hwconfig <enable|disable|list>" commands, ncurses | |
| 7 | interface for Award BIOS-like interface, and frame-buffer | |
| 8 | interface for AMI GUI[1] BIOS-like interface with mouse | |
| 9 | support[2]. | |
| 10 | ||
| 11 | Current implementation details/limitations: | |
| 12 | ||
| 13 | 1. Doesn't support options dependencies and mutual exclusion. | |
| 14 | We can implement this by integrating apt-get[3] into Das | |
| 15 | U-Boot. But I haven't bothered yet. | |
| 16 | ||
| 17 | 2. Since we don't implement a hwconfig command, i.e. we're working | |
| 1bce2aeb | 18 | with the environment directly, there is no way to tell that |
| ab68f4dd HS |
19 | toggling a particular option will need a reboot to take |
| 20 | effect. So, for now it's advised to always reboot the | |
| 21 | target after modifying the hwconfig variable. | |
| 22 | ||
| 23 | 3. We support hwconfig options with arguments. For example, | |
| 24 | ||
| 25 | set hwconfig "dr_usb:mode=peripheral,phy_type=ulpi" | |
| 26 | ||
| 27 | This selects three hwconfig options: | |
| 28 | 1. dr_usb - enable Dual-Role USB controller; | |
| 29 | 2. dr_usb_mode:peripheral - USB in Function mode; | |
| 30 | 3. dr_usb_phy_type:ulpi - USB should work with ULPI PHYs. | |
| 31 | ||
| 32 | The purpose of this simple implementation is to refine the | |
| 33 | internal API and then we can continue improving the user | |
| 34 | experience by adding more mature interfaces, like a hwconfig | |
| 35 | command with bells and whistles. Or not adding, if we feel | |
| 36 | that the current interface fits people's needs. | |
| 37 | ||
| 38 | [1] http://en.wikipedia.org/wiki/American_Megatrends | |
| 39 | [2] Regarding ncurses and GUI with mouse support -- I'm just | |
| 40 | kidding. | |
| 41 | [3] The comment regarding apt-get is also a joke, meaning that | |
| 42 | dependency tracking could be non-trivial. For example, for | |
| 43 | enabling HW feature X we may need to disable Y, and turn Z | |
| 44 | into reduced mode (like RMII-only interface for ethernet, | |
| 45 | no MII). | |
| 46 | ||
| 47 | It's quite trivial to implement simple cases though. |