Signed-off-by: Heiko Schocher <h...@denx.de> --- changes since v1: - spelling check from Mike Frysinger, thanks!
doc/README.hwconfig | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 51 insertions(+), 0 deletions(-) create mode 100644 doc/README.hwconfig diff --git a/doc/README.hwconfig b/doc/README.hwconfig new file mode 100644 index 0000000..a4f489a --- /dev/null +++ b/doc/README.hwconfig @@ -0,0 +1,51 @@ +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 bother 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. + -- 1.6.2.5 -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
