[U-Boot] dra7xx: booting from eMMC raw boot partition

Tom Rini
2013-11-21T19:02:14Z

On Thu, Nov 21, 2013 at 01:20:08PM -0500, Richard Retanubun wrote:
> On 21/11/13 01:09 PM, Tom Rini wrote:
> >I've done RAW mode booting on my omap5_uevm as well as am335x-based
> >platforms, on SD card and eMMC. But in the case of eMMC it's always the
> >user partitions. I suspect the answer is that for automotive booting
> >you need silicon that supports that, much like the difference between HS
> >and GP devices.
>
> Agreed. If by silicon you mean the CPU, then all the docs I've seen
> (the TRM for DRA7xx and SYSBOOT in automotive peripheral mode seem to
> indicate that the SoC is capable or Raw eMMC boot partition booting.

Well, I think it's a little more than that, perhaps depending on eFuse
stuff or similar as well.

> >I'm not sure what code in p-ti-u-boot-2013.04 hasn't
> >been merged to mainline but if you can give me some pointers I can go
> >and poke some folks.
> Thanks for the offer, poke gently :)
>
> I think it is essentially all the code that touches /drivers/mmc/spl_mmc.c on the ti tree here:
>
> http://git.omapzoom.org/?p=repo/u-boot.git;a=history;f=drivers/mmc/spl_mmc.c;h=bd7e34bed35a1518d714232a8aedbc2e38d43632;hb=refs/heads/p-ti-u-boot-2013.04

Ah, OK, I see where the confusion comes from. There are three things in
that tree, roughly, from reading the commits on that file:
1) Android Fastboot support
2) A custom version of "falcon mode"
3) Other odds and ends changes

Looking over the code there, one might think mainline doesn't support
eMMC booting or needs changes, because we always say "use mmc device 0".
That's fine however because SPL looks at if we came in (hardware
numbering now) from MMC1 or MMC2 and then only register that MMC device.
So we're always s/w wise mmc device 0.

There's a few patches floating around to add Fastboot support to
mainline, and I'd love to see one pushed all the way to mainline.

--
Tom
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