[U-Boot] 2015.10-rc2 Chromebook Snow boot failure

[Simon Glass]

Hi Misha,

On 24 August 2015 at 03:55, Misha Komarovskiy <zombah at gmail.com> wrote:
> Hello Simon,
> Confirmed, with vdd_arm set 1.1, snow boots fine.
> ---
> Best Regards,
> Misha Komarovskiy
> zombahatgmaildotcom

Please avoid top posting as it leads to a confusing thread.

Would you like to send a patch to update this?

>
>
> On Mon, Aug 24, 2015 at 12:31 PM, Misha Komarovskiy <zombah at gmail.com> wrote:
>> Hello Simon,
>> 2015.07 and 2015.10-rc1 both boot fine. I use this U-Boot as third
>> stage from SD card/USB stick, im not quite
>> sure what right name for this position from reset vector.
>> I will try to increase  ret = exynos_set_regulator("vdd_arm",
>> 1000000); to 1100000 and report result.

You say it is a 3rd-stage - does that mean you are booting U-Boot
after the existing SPL and U-Boot have already run? That would explain
the problem, since the built-in U-Boot sets the CPU speed to maximum.

We don't have support for CPU clock adjustment in mainline yet.

>> ---
>> Best Regards,
>> Misha Komarovskiy
>> zombahatgmaildotcom
>>
>>
>> On Mon, Aug 24, 2015 at 12:21 AM, Simon Glass <sjg at chromium.org> wrote:
>>> Hi,
>>>
>>> On 21 August 2015 at 09:55, Misha Komarovskiy <zombah at gmail.com> wrote:
>>>> Hello,
>>>> I have failure in attempt to boot Chromebook Snow with 2015.10-rc2
>>>> build snow_defconfig, here is error message, it maybe not full as i
>>>> have some noise on serial console with device:
>>>>
>>>> U-Boot 2015.10-rc2 (Aug 21 2015 - 15:43:43 +0000) for snow
>>>> GPU:   Exynos5250 @ 1.7 GHz
>>>> Model: Google Snow
>>>> Board: Google Snow
>>>> DRAM:  2 GiB
>>>> ERROR: read error from device: bad39118 register: 0x1e!
>>>> at drivers/power/pmic/max77686.c:44/max77686_read()
>>>> initcall sequence bfdaf3bc failed at call 43e0418c (err=-5)
>>>> ### ERROR ### Please RESET the board ###
>>>
>>> Register 1e is the BUCK3 voltage - see max77686.h.
>>>
>>> I don't get the same addresses as you but I suppose we are using
>>> different toolchains.
>>>
>>> But this is probably being called from exynos_power_init().
>>>
>>> The ARM voltage is set to 1.0V. I wonder if that is borderline? We
>>> could increase it perhaps to 1.1V. - See the exynos_set_regulator()
>>> line for vdd_arm.
>>>
>>> It was previous 1.3V in 2015.07 - see max77686_init().
>>>
>>> Are you starting U-Boot SPL directly from the reset vector?
>>>
>>> Regards,
>>> Simon

Regards,
Simon