Mount root from SD card?

[Krassimir Slavchev]

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Boot with verbose messages is here:

http://mnemonic.bulinfo.net/~krassi/ARM/arm.verbose


Alexander Motin wrote:
> Krassimir Slavchev wrote:
>> This is the output:
>>
>> CMD: 0 ARG 0 len 0
>> RES: 0
>> CMD: 8 ARG 1aa len 0
>> RES: 1
>> CMD: 37 ARG 0 len 0
>> RES: 0
>> CMD: 29 ARG 0 len 0
>> RES: 0
>> CMD: 0 ARG 0 len 0
>> RES: 0
>> CMD: 8 ARG 1aa len 0
>> RES: 1
>> CMD: 37 ARG 0 len 0
>> RES: 0
>> CMD: 29 ARG ff8000 len 0
>> RES: 0
>> CMD: 37 ARG 0 len 0
>> RES: 0
>> CMD: 29 ARG ff8000 len 0
>> RES: 0
>> CMD: 2 ARG 0 len 0
>> RES: 0
>> CMD: 3 ARG 0 len 0
>> RES: 0
>> CMD: 9 ARG 10000 len 0
>> RES: 0
>> CMD: 7 ARG 10000 len 0
>> RES: 0
>> CMD: 37 ARG 10000 len 0
>> RES: 0
>> CMD: 33 ARG 0 len 8
>> RES: 0
>> CMD: 6 ARG ffffff len 64
>> RES: 0
>> CMD: 37 ARG 10000 len 0
>> RES: 0
>> CMD: d ARG 0 len 64
>> RES: 2
>> CMD: 37 ARG 10000 len 0
>> RES: 0
>> CMD: d ARG 0 len 64
>> RES: 0
> 
> This part looks fine. Just normal SD detection and initialization.
> 
> Somewhere here bus frequency and high-speed timings negotiated:
> 
>> CMD: 7 ARG 0 len 0
>> RES: 0
>> CMD: 7 ARG 10000 len 0
>> RES: 0
>> CMD: 7 ARG 0 len 0
>> RES: 0
>> CMD: 7 ARG 10000 len 0
>> RES: 2
>> CMD: 6 ARG 80fffff0 len 64
>> RES: 0
>> CMD: 7 ARG 0 len 0
>> RES: 0
>> mmcsd0: 1983MB <SD Memory Card> at mmc0 30MHz/1bit
> 
> Then regular card activity beging:
> 
> - select the card - error
>> CMD: 7 ARG 10000 len 0
>> RES: 2
> 
> - select bus width - normal ??
>> CMD: 37 ARG 10000 len 0
>> RES: 0
>> CMD: 6 ARG 0 len 0
>> RES: 0
> 
> - read some sectors - normal ??
>> CMD: 11 ARG 0 len 512
>> RES: 0
>> CMD: 11 ARG 0 len 512
>> RES: 0
>> CMD: 11 ARG 200 len 512
>> RES: 0
>> Trying to mount root from ufs:/dev/mmcsd0s1
> 
> It's a bis strange to me that this card selection request failed, while
> previous ones during initialization managed fine. May be card or
> controller unable to handle such speed, or may be bus just hasn't
> managed to settle new parameters until that command.
> Also interesting what are the reading command returned after card select
> command failed.
> 
> Boot with verbose messages enabled should show when exactly frequency
> has changed. Do it please.
> 
>>>> Also sysinstall crashes when trying to create a new slice.
>>>> May be because:
>>>> Disk name:      mmcsd0                                    FDISK
>>>> Partition Editor
>>>> DISK Geometry:  0 cyls/0 heads/0 sectors = 0 sectors (0MB)
>>> I don't think it is related. There is no such thing as disk geometry on
>>> flash card, that's why driver does not announce it. The only places
>>> where it may be important is when fdisk is trying to align partitions
>>> with track boundaries for compatibility with legacy BIOS'es.
>>> There is no problem to report some fake values, but from one side they
>>> should better match BIOS assumptions on geometry and from other, they
>>> should as much as possible to match flash erase sector size. I just have
>>> no any system which supports SD booting to report something reasonable
>>> there. Reporting maximal 63 sectors per track as for HDD may result in
>>> ineffective filesystem alignment and reduced performance.
>> At least sysinstall should be fixed. Should I fill a PR for this?
> 
> Probably yes. I haven't looked into sysinstall.
> 

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