[U-Boot] i.MX dcache issues

[Marek Vasut]

Dear 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=e576bd90f9
> > > > 4080 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.

AARGH! Thank you very much!

> Best regards,
> Benoît

Best regards,
Marek Vasut