[U-Boot] [PATCH 17/20] tegra: nyan-big: Add additional clock and kernel init

Simon Glass
2015-03-29T13:02:02Z

Hi Stephen,

On 25 February 2015 at 16:23, Stephen Warren <swarren@wwwdotorg.org> wrote:
> On 02/17/2015 03:29 PM, Simon Glass wrote:
>>
>> We need to turn on all audio-related clocks for the kernel to boot.
>> Otherwise it will hang when trying to enable audio.
>
>
> This certainly isn't true for the upstream kernel; is this some bug in the
> ChromeOS kernel? If so, we should explicitly call this out in the commit
> description.

OK I'll adjust the commit message. At some point perhaps this problem
will go away. Chrome OS is running kernel v3.10 on this device.

>
>> Also for Linux set up the ODMDATA and graphics driver video protection.
>
>
> Why doesn't ODMDATA come from the BCT? The way this is suppose to work is
> that the boot ROM copies the BCT into IRAM, and U-Boot (or indeed any
> bootloader) copies the ODMDATA field from the BCT in IRAM into the PMC
> scratch20 register. This logic is already all in place in U-Boot, and indeed
> any NVIDIA-authored bootloader AFAIK.

OK, so perhaps I can just drop this code. It might just be a hack in Coreboot.

>
> Is this U-Boot port intended to run as a Coreboot payload rather than
> natively, and Coreboot is somehow corrupting the copy of the BCT in IRAM? If
> so, we should explicitly call this out in the commit description.

No, there really isn't any point in running U-Boot as a Coreboot
payload, since U-Boot can do all the init itself. This series is for
running U-Boot stand-alone on Nyan-big.

>
> I would personally want to (be able to) make my SPI flash r/w and replace
> Coreboot with U-Boot. Perhaps we need different board names for those two
> use-cases; something like nyan-big for the Coreboot payload, and
> nyan-big-native for the version you'd write directly into SPI?

See above... if we can get the display stuff merged then I could do
this also. But without a display it's missing a big piece.

Regards,
Simon