[U-Boot] i.MX dcache issues

[Marek Vasut]

Dear Dirk Behme,

> On 15.07.2012 00:08, Benoît Thébaudeau wrote:
> > On Sat, Jul 14, 2012 at 11:28:03PM +0200, Benoît Thébaudeau wrote:
> >> Shouldn't the MMC/eSDHC drivers flush/invalidate the dcache ranges
> >> that they use
> >> for DMA operations? Not doing so would explain why stack-allocated
> >> buffers are
> >> more affected than buffers in unused RAM areas.
> > 
> > That will help:
> > http://git.denx.de/?p=u-boot/u-boot-mmc.git;a=commitdiff;h=e576bd90f94080
> > 6b989ffd666552081f17f032c8
> 
> Are you sure that this patch does really help?
> 
> If I remember correctly (will re-check) we have this patch locally
> applied. But even with this patch, we have issues so that we enabled
> CONFIG_SYS_DCACHE_OFF, i.e. disabled the dcache.

Try using the bounce buffer as I do on mx28.

> The issues we observed *without* CONFIG_SYS_DCACHE_OFF: The SD card
> was detected as 1-bit only (mmcinfo), while with dcache off it was
> used as 4-bit. Debugging this showed that wrong configuration data was
> read [1]. Having a fat partition on the card, mmc part/fatls etc
> failed, too, with cache enabled.

Ad caches -- FEC should be fixed on these platforms, USB might work, MMC should 
work if you use the bounce buffer. FAT should be fixed, so should be ext2

> Best regards
> 
> Dirk
> 
> [1]
> 
> http://git.denx.de/?p=u-boot.git;a=blob;f=drivers/mmc/mmc.c;h=aebe578ff6f2e
> 0228baa3e5d010f6808ea269760;hb=HEAD#l856
> 
> mmc->scr[0]/scr[1] contained random data
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Best regards,
Marek Vasut