Ben Nizette bn@niasdigital.com wrote:
On Tue, 2008-09-02 at 14:09 +0200, Haavard Skinnemoen wrote:
Right. I was thinking maybe we could extend the boot protocol to pass partitioning information from u-boot to the kernel -- that should make it possible to run the same kernel on boards with different flash layout as long as the in-flash u-boot is consistent with the flash layout.
If we do end up with libfdt on avr32 then we solve our problems here too, we can encapsulate this partitioning in the fdt image.
Yes, we can probably do that. I guess it all depends on what we want to do first.
But, as I understand it, that involves not only the actual libfdt support but making all avr32 driver nice and OF compatible. At least, if we want the fdt support to be _useful_ then that needs to happen (CMIIW).
Or we could just add a glue layer which creates platform_devices based on the fdt information. Perhaps pass along a pointer to the device tree node for drivers that want to peek at it. PowerPC has a of_node in struct dev_archdata for this purpose I believe.
One problem this doesn't solve is that if you load an older kernel which doesn't understand the extended boot protocol, it will keep using the old flash layout.
Doesn't the MTD system have facility to override partitioning information from the boot arguments? If so then any big u-boots can just ship with such a clause in their default bootargs, job done. Have to look in to that...
Yes. But it won't fix boards which already have a valid environment and just want to upgrade u-boot. We could perhaps fix up the bootargs and add partitioning information when preparing to boot the kernel...
Haavard