Re: [PATCH 0/3] patches to allow DTB to be appended to the ARM zImage

[Dmitry Eremin-Solenikov <dbaryshkov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

Russell King - ARM Linux wrote:

> On Sun, Jun 12, 2011 at 06:42:16PM +0800, Shawn Guo wrote:
>> On Sun, Jun 12, 2011 at 10:52:17AM +0100, Russell King - ARM Linux wrote:
>> > On Sun, Jun 12, 2011 at 05:38:23PM +0800, Shawn Guo wrote:
>> > > On Sun, Jun 12, 2011 at 10:21:31AM +0100, Russell King - ARM Linux wrote:
>> > > > What if your platform doesn't use uboot?
>> > > 
>> > > Add dtb parsing support with the help from libfdt, I guess.  It is
>> > > some amount of work, but it's not a rewrite of bootloader, IMHO.
>> > 
>> > I guess you're suggesting that this wrapper uses libfdt to merge
>> > the ATAGs with the DT info?
>> > 
>> No, ATAGs does not play at all in this case.  For u-boot example
>> again, if it boots a dt kernel, dtb will be parsed to get cmdline
>> node overwritten as bootargs env value, and then it boots the dt
>> kernel with this updated dtb.
>
> You've missed my point entirely.  What you're saying is that we have to
> re-build and replace the boot loader in order to pass a command line into
> a kernel using the DT wrapper.
>
> I'm saying that you shouldn't have to, and the kernel should accept the
> memory size and command line from the ATAGs _in addition_ to the
> appended DT blob, and the ATAGs in that case should take precidence.

... exactly like cuboot* preloaders are patching dtb on the powerpc
systems, where U-Boot doesn't understand dtb.

-- 
With best wishes
Dmitry