On 08/16/2013 02:30 PM, Brendan Conoboy wrote:
On 08/15/2013 10:07 AM, Tom Rini wrote:
What I don't see above is something about loading the full DTB from non-volatile storage and into memory.
Implicit assumption: When the bootloader comes up it has already put the DTB into place.
OK, lets spell that out.
The only problem I see is you're not dealing with platforms that don't include non-volatile storage on the board itself (Beaglebone White, Pandaboard, RPi, Allwinner boards without eMMC/NAND, etc). Or are you including somehow stored on SD card in the list?
Yeah, this is a something of a pain point, but more for OS vendors needing to provide a suitable uBoot. DTB is just a subset of that problem. If the platform itself doesn't provide non volatile storage I think it's reasonable to ask that the boot loader still automatically retrieve a known-good DTB by whatever means make sense for the device. The only reason the OS should be involved in the DTB equation is when the supplied DTB content is in some way deficient relative to the needs of the kernel interpreting it.
OK, I think I can go with this, with the constraint / understanding that it also means the DT lives somewhere firmware-happy. Using TI platforms as an example, the SD card would have the FAT partition with MLO/u-boot.img/foo.dtb on it, since ROM groks FAT.