[U-Boot] u-boot for Snow problem

[Simon Glass]

Hi Michal,

On 17 April 2015 at 12:49, Michal Suchanek <hramrach at gmail.com> wrote:
> On 15 April 2015 at 19:01, Michal Suchanek <hramrach at gmail.com> wrote:
>> On 15 April 2015 at 17:00, Simon Glass <sjg at chromium.org> wrote:
>>> Hi Michal,
>>>
>>> On 14 April 2015 at 16:10, Michal Suchanek <hramrach at gmail.com> wrote:
>>>> Hello,
>>>>
>>>> On 4 March 2015 at 00:46, Simon Glass <sjg at chromium.org> wrote:
>>>>> Hi Michal,
>>>>>
>>>>> On 2 March 2015 at 04:25, Michal Suchanek <hramrach at gmail.com> wrote:
>>>>>> Hello,
>>>>>>
>>>>>> On 18 February 2015 at 06:24, Michal Suchanek <hramrach at gmail.com> wrote:
>>>>>>> On 18 February 2015 at 03:27, Simon Glass <sjg at chromium.org> wrote:
>>>>>>>> Hi Michal,
>>>>>>>>
>>>>>>>> On 16 February 2015 at 04:41, Michal Suchanek <hramrach at gmail.com> wrote:
>>>>>>>>> On 13 February 2015 at 05:51, Simon Glass <sjg at chromium.org> wrote:
>>>>>>>>>> Hi Michal,
>>>>>>>>>>
>>>>>>>>>> On 11 February 2015 at 10:16, Michal Suchanek <hramrach at gmail.com> wrote:
>>>>>>>>>>>
>>>>>>>>>>> Hello,
>>>>>>>>>>>
>>>>>>>>>>> I changed the SYS_START to work around the bug in the manufacturer
>>>>>>>>>>> firmware, applied snow_defconfig, built u-boot.bin, packed it into
>>>>>>>>>>> kernel uimage, signed it, copied it to a kernel partition, bumped
>>>>>>>>>>> priority of the partition, and rebooted.
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Do you mean u-boot-dtb.bin? If not you won't get a device tree and it
>>>>>>>>>> won't work.
>>>>>>>>>
>>>>>>>>> No, u-boot.bin. With u-boot-dtb.bin I get a snow # prompt on the
>>>>>>>>> built-in LCD, and working keyboard.
>>>>>>>>
>>>>>>>> OK sounds like it is working, good! I wonder if we should have a page
>>>>>>>> on elinux.org?
>>>>>>
>>>>>> It is working to some extent.
>>>>>>
>>>>>> I managed to load kernel from the emmc which works fine but the kernel
>>>>>> cannot read the emmc after it boots because it does not properly parse
>>>>>> the partitioning scheme. This should be trivially fixable in the
>>>>>> kernel and might actually work if I updated my sources but rebasing
>>>>>> the extra patches required for Snow is not automatically handled.
>>>>>>
>>>>>> On the other hand, the linux kernel has no problem with the SDXC card
>>>>>> in the SD slot and can read it just fine. Unfortunately, u-boot
>>>>>> complains about EFI partition errors and won't load anything from the
>>>>>> card. I tried two different GPT partitioning tools on the card and
>>>>>> both say that the partition layout is fine and that I have the default
>>>>>> 128 entries.
>>>>>>
>>>>>> How can I tell why u-boot does not like my GPT label?
>>>>>
>>>>> You could debug it in U-Boot and see what is going wrong.
>>>>>
>>>>
>>>> Apparently the problem is that the dw mmc controller fails and the
>>>> sectors are unreadable. U-boot sometimes reports timeout, sometimes
>>>> data error, and sometimes nothing because the result has already been
>>>> cached probably. And the reason the dw mmc controller fails is that
>>>> port 1 is disabled. Not using disabled controllers would probably
>>>> solve the problem.
>>>
>>> Seems strange. Can you post details of which commit you are building
>>> and the console output? I could try it too.
>>
>>
>> Sorry, I don't have the tree anymore.
>>
>> None of my trees has the commit to relocate away from the address
>> clobbered by the Snow ro firmware.
>>
>> I tried looking again what actually happens but none of the mmc
>> commands shows which exact mmc interfaces I have. U-boot somehow picks
>> 2 of the 4 dwmmc interfaces the Exynos chip has and I suspect the
>> second one is picked or multiplexed wrong. The mmc0 to which emmc is
>> connected works fine but mmc2 connected to the external slot always
>> fails (on Snow mmc1 is unused and mmc3 is WiFi).
>>
>
> Ok, I did the chainload dance and I am running u-boot master patched
> so it prints the IO address in mmc list and now
>
> 1) both mmc interfaces work
> 2) I can see the correct mmc interface is used in mmc list
>
> So it was broken for whatever reason and is fixed.

OK great. If you have time you could post the details at elinux.org or similar.

Regards,
Simon