SD card probe failure

[Roberto Nibali]

Hi

> What's going on here? I'll investigate this further, because in real life
> I
> > have massive SD card write speed issues on my mx25 device on any kernel
> > tested from 2.6.37 to 3.3.4 so far.
>
> I try to keep the iomux descriptions in sync with the kernel. So when
> there is a bug in the kernel it's likely present in barebox aswell.
> Another thing which you might want to investigate is the clock
> frequency. Please check with an oscilloscope if we really have 25MHz as
> suggested above.
>
>
I used exactly the same iomux descriptions, but we have the same issue in
the kernel with huge timeouts. One of the reasons I try to switch to
barebox is its simplicity of the driver ideology close to the kernel. Also,
what are the default pin mux settings for the ESDHC on mx25, if I comment
the following?

        /*
        MX25_PAD_SD1_CMD__SD1_CMD,
        MX25_PAD_SD1_CLK__SD1_CLK,
        MX25_PAD_SD1_DATA0__SD1_DATA0,
        MX25_PAD_SD1_DATA1__SD1_DATA1,
        MX25_PAD_SD1_DATA2__SD1_DATA2,
        MX25_PAD_SD1_DATA3__SD1_DATA3,
        */

I thought it might just fallback to the same pin mux but without the 47k
pullup (NO_PAD_CTRL). This does not seem to be the case, because I have
replaced the definition of the iomux definitions with NO_PAD_CTRL and the
problem remains. Only commenting them out seems to have an effect. So,
something is either really wrong with my hardware or there has to be
another influence.

The oscilloscope shows 190kHz when it fails, 33.33MHz when it works ....
interesting. Barebox initializes mpll to 532Mhz and consequently sets sdhc1
to 66.5Mzh. Invoking 'cpufreq 399' resets the clocks, however does not
adjust the sdhc1 one as on the oscilloscope it stays on 33.33Mhz.

What next?

Cheers
Roberto
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