[U-Boot] spl_mmc: allow to load raw image

[Alexander Graf]

On 02.05.16 04:29, Derald D. Woods wrote:
> On 05/01/2016 09:17 PM, Derald D. Woods wrote:
>> On 05/01/2016 08:57 PM, Tom Rini wrote:
>>> On Sun, May 01, 2016 at 08:32:48PM -0500, Derald D. Woods wrote:
>>>> On 05/01/2016 03:37 AM, Masahiro Yamada wrote:
>>>>> Hi Adam,
>>>>>
>>>>>
>>>>> 2016-04-30 3:06 GMT+09:00 Adam Ford <aford173 at gmail.com>:
>>>>>> On Fri, Apr 29, 2016 at 12:53 PM, Tom Rini <trini at konsulko.com>
>>>>>> wrote:
>>>>>>> On Fri, Apr 29, 2016 at 09:59:00AM -0500, Adam Ford wrote:
>>>>>>>
>>>>>>>> Does anyone with an OMAP3 board have any issues with this patch?  I
>>>>>>>> will admit I haven't stayed on top of stuff due to moving, and
>>>>>>>> other
>>>>>>>> issues at home, but I pulled down the master to reviews some on
>>>>>>>> related stuff, and found that master doesn't boot.  I used git
>>>>>>>> bisect
>>>>>>>> this morning and it narrowed down a problem with booting to this
>>>>>>>> patch.
>>>>>>>>
>>>>>>>> With the patch, I get:
>>>>>>>>
>>>>>>>> U-Boot SPL 2016.03-00378-g4976f48 (Apr 29 2016 - 09:25:27)
>>>>>>>> Trying to boot from MMC
>>>>>>> OK.  Do you have u-boot.bin or u-boot.img (which?) written to the
>>>>>>> raw
>>>>>>> offset in MMC or from filesystem?  Based on the log it looks like
>>>>>>> filesystem.
>>>>>> I have u-boot.img copied to the fatfs on the card, but I didn't
>>>>>> put it
>>>>>> in a specific location.
>>>>>>
>>>>>> I never used to have to do that.  Is this a new behavior and is it
>>>>>> documented somewhere?
>>>>>>
>>>>>> adam
>>>>> You are expecting to boot it from FAT,
>>>>> but I think spl_boot_mode() on your board returns MMCSD_MODE_RAW.
>>>>>
>>>>> Can you fix the function to return MMCSD_MODE_FS?
>>>>>
>>>>>
>>>>>
>>>>> This commit changed to allow to load raw U-Boot image,
>>>>> so MMCSD_MODE_RAW never fails.
>>>>>
>>>>> So, you can no longer rely on the former behavior
>>>>> "try MMCSD_MODE_RAW first, and fallback to MMCSD_MODE_FS".
>>>>>
>>>> So everyone loading MLO from the FAT filesystem is now wrong? I am
>>>> trying to understand how this came into being the default.
>>> ... yes, we can't break the case of SPL+U-Boot being on FS on MMC1.  I
>>> wonder if:
>>> commit 22d90d560a2b01c47f180e196e6c6485eb8e65db
>>> Author: Alexander Graf <agraf at suse.de>
>>> Date:   Tue Mar 1 09:56:34 2016 +0100
>>>
>>>      omap3: Use raw SPL by default for mmc1
>>>
>>> Isn't part of what's going wrong now.
>>>
>> Reverting that commit worked for me!
>>
>> ---8<----------------------------------------------
>>
>> U-Boot SPL 2016.05-rc3-00012-gfccdb28-dirty (May 01 2016 - 21:10:05)
>> Trying to boot from MMC1
>> reading args
>> spl_load_image_fat_os: error reading image args, err - -1
>> reading u-boot.img
>> reading u-boot.img
>>
>>
>> U-Boot 2016.05-rc3-00012-gfccdb28-dirty (May 01 2016 - 21:10:05 -0500)
>>
>> OMAP3630/3730-GP ES1.2, CPU-OPP2, L3-200MHz, Max CPU Clock 1 Ghz
>> Logic DM37x/OMAP35x reference board + LPDDR/NAND
>>
>> ---8<----------------------------------------------
>>
>> Derald
>>
>>
> 
> I should also mention that I have Tom's patch from this mailing list
> thread:
> 
> "[U-Boot] [PATCH] omap3: Reduce logic/overo SPL max image size"
> 
> So with the reversion and patch I can boot master on 'omap3_logic' again.

Ok, so I'm puzzled. The raw boot path can basically never fail, since
all it does is to verify whether we could read the sectors - and that
usually works:

http://git.denx.de/?p=u-boot.git;a=blob;f=common/spl/spl.c;h=82e7f58e80f028f7517ec52bd0d73566dae82d28;hb=HEAD#l115

So how could we ever fall back from raw to fs mode? I can see how we
could fall back from fs loading to raw loading, but the other way around?

Guillaume, you posted a patch a while back to handle exactly that case.
How did you get there?

The only real "fix" to this I can think of is to reverse the fallback
path. Load from fs, fall back to raw. Because with file systems we know
whether something failed.


Alex