[U-Boot] i.MX dcache issues

[Benoît Thébaudeau]

Hi all,

On Tue, Jul 17, 2012 at 12:30:22AM +0200, Marek Vasut wrote:
> 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

I have switched to the git head, and applied all the latest EHCI/MSC patches
from u-boot-usb-next. Since then, all my MMC/EHCI/FEC i.MX DMA issues are
resolved, except on i.MX35 because of a huge bug in the handling of cache range
checks on ARM1136. I have just posted a patch that fixes this issue.

Best regards,
Benoît