-----Original Message----- From: glikely@gmail.com [mailto:glikely@gmail.com] On Behalf Of Grant Likely Sent: den 17 december 2006 16:11 To: Joakim Tjernlund Cc: wd@denx.de; u-boot-users@lists.sourceforge.net Subject: Re: [U-Boot-Users] builtin OF tree dtb gone
On 12/17/06, Joakim Tjernlund joakim.tjernlund@transmode.se wrote:
"in some setups", that's the point. Our setup works fine with an embedded OF tree in u-boot. If I am to adapt to this new method of supplying the OF tree, not only will I have to repartion the flash to fit the tree in there, I also need to make sure that some 15-20 people learns this new concept for no real gain.
It is nothing wrong with having the ability provide a OF tree at boot time, but forcing everyone to do so is. The most flexible way is to have both.
This shouldn't be too big a deal. Add the code back for linking the .dtb into the image. Look in common/boot.c and add a check for if the third bootm parameter is '-'. If it is, then use the builtin section for the .dtb address. Then you can either use the builtin version, or pass a new one. We're not talking a lot of code here.
I am looking at this now. I have a DTB linked into uboot at address 0xffc9d90(near end of my 256MB RAM when u-boot has relocated itself). Passing this address to bootm $loadaddr - 0xffc9d90 makes the kernel SEGV because the kernel can't access data that high up in RAM early in the boot process. Seems to that the u-boot should copy the DTB to an address that the kernel can access before passing control the kernel. How else is one supposed to have a DTB in flash that is even higher up in the address space?
Maybe I have misunderstood something, but I can't se what presently.
Alternately; your u-boot image does not totally fill the sectors you have allocated for it. Since your plan is to update u-boot and the .dtb at the same time; modify your u-boot build procedure (I think by using objcopy) to link your .dtb to a known address within the unused part of the u-boot sectors (so that u-boot+dtb are in a single file) and make sure the update procedure also changes the default bootm command to include the known dtb address.
This option does not really suit me, but thanks for the suggestion.
Jocke