Hi Gabe,
On 30/11/11 17:25, Gabe Black wrote:
On Tue, Nov 29, 2011 at 7:48 PM, Graeme Russ <graeme.russ@gmail.com mailto:graeme.russ@gmail.com> wrote:
Hi Gabe, On Wed, Nov 30, 2011 at 2:11 PM, Gabe Black <gabeblack@chromium.org <mailto:gabeblack@chromium.org>> wrote: > These two patches add support for the 32 bit Linux boot protocol to the > zboot command. Going by our previous offline correspondence, I assume this approach still uses the bzImage's decompression stub? Also, as I discussion offline previously, I'm going through the boot_params with a fine-tooth comb to get a complete picture of what the Linux kernel actually requires to be filled out in the boot_params structure - I expect this will result in a 'built_boot_params()' function which is called by zboot and bootm - possibly with some weak stubs to helper functions Regards, GraemeYes, this supports the 32 bit protocol which includes the decompression stub. I don't think a build_boot_params function which actually builds the bootstub would work for a number of reasons. First, that's not how the boot protocol works. The kernel provides information there that u-boot needs to read, and u-boot shouldn't just make it up. An example of this is what boot protocol is expected. Second, you might find all the things a particular version of the kernel wants right now, but that could easy change at any time and break booting. Third, the boot_params structure isn't compressed (because otherwise the bootloader couldn't fill it out) and building our own wouldn't serve any purpose.
If you mean consolidating the existing boot_params code so that both zboot and bootm can use it, that seems reasonable. I'd point out, though, that filling out the table takes a trivial amount of time, so trying to cut corners and not fill it out completely would not only be dangerous, it would very likely not be worth the effort.
I've been playing around tonight and have managed to embed a gzip'd vmlinux and raw header (stripped from the associated bzImage) into my U-Boot image but I end up getting the same results - No RAM :(
So proof of concept is good
Regards
Graeme