Since board_hwconfig & cpu_hwconfig are defined as weak and dont have a
default value they will get put into the BSS if they aren't defined
elsewhere. This is problematic as we try to utilize hwconfig before
we've relocated and thus BSS isn't setup.
Instead of giving dummy values in the board files that utilize this
feature, we can just initialize the variables to an empty string and
thus move them out of the BSS if they aren't defined elsewhere.
Also made board_hwconfig & cpu_hwconfig arrays to reduce size associated
with string pointers vs arrays.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Since we use hwconfig in cases before relocation (like getting DDR
params on FSL PPC systems), we can have strings that exceed the early
small (32 byte) buffer size that getenv will handle.
So we explicitly allocate our own buffer on the stack and use if to
handle getting the hwconfig env string. We currently utilize a string
length of 128 bytes.
This allows us to get rid of boot messages like:
env_buf too small [32]
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
For the following hwconfig string:
key1:subkey1=value1,subkey2=value2;key2:value3
The subkey2 cannot be extracted correctly. The parsing code looks
for comma as a stopch, but there may be two kind of stop characters:
a comma and a semicolon.
Currently the code would return "value2;key2:value3", while just
"value2" is the correct answer.
This patch fixes the issue by making the code aware of multiple
stop characters.
For old U-Boots, the issue can be workarounded by placing a comma
before a semicolon, i.e.:
hwconfig=key1:subkey1=value1,subkey2=value2,;key2:value3
Reported-by: York Sun <yorksun@freescale.com>
Signed-off-by: Anton Vorontsov <avorontsov@mvista.com>
This patch implements simple hwconfig infrastructure: an
interface for software knobs to control a hardware.
This is very simple implementation, i.e. it is implemented
via `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 the
u-boot. But I didn't bother yet.
2. Since we don't implement 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
an effect. So, for now it's advised to always reboot the
target after modifying hwconfig variable.
3. We support hwconfig options with arguments. For example,
set hwconfig dr_usb:mode=peripheral,phy_type=ulpi
That means:
- dr_usb - enable Dual-Role USB controller;
- dr_usb:mode=peripheral - USB in Function mode;
- dr_usb:phy_type=ulpi - USB should work with ULPI PHYs;
The purpose of this simple implementation is to define some
internal API and then we can continue improving user experience
by adding more mature interface, like hwconfig command with
bells and whistles. Or not adding, if we feel that current
interface fits its 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.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: Kim Phillips <kim.phillips@freescale.com>
Kumar Gala
Anton Vorontsov
Anton Vorontsov