[U-Boot] [PATCH v4 3/6] mcx: Disable DCACHE since USB EHCI is enabled

Marek Vasut
2012-06-28T22:36:59Z

Dear Tom Rini,

> On Fri, Jun 29, 2012 at 12:01:58AM +0200, Marek Vasut wrote:
> > Dear Tom Rini,
> >
> > > On 06/28/2012 07:37 AM, Marek Vasut wrote:
> > > > Dear Ilya Yanok,
> > > >
> > > >> Dear Marek,
> > > >>
> > > >> 28.06.2012 02:48, Marek Vasut wrote:
> > > >>>> Sorry for missing this discussion. I think compile-time disabling
> > > >>>> of the cache is too brutal.
> > > >>>> ehci-hcd cache handling is broken anyway: doing unaligned
> > > >>>> flushes/invalidates is a bug, and we know for sure that upper
> > > >>>> layers don't care about alignment (and I bet ehci-hcd does this
> > > >>>> even for its internal buffers). So what's the point in all this
> > > >>>> cache handling in ehci-hcd? It's not going to work anyway and
> > > >>>> just produces problems. So I suggest to just disable all this
> > > >>>> stuff until generic code will be fixed. Alternatively we can do
> > > >>>> bounce-buffering inside driver.
> > > >>>
> > > >>> We should rather introduce generic bounce buffer. But the upper
> > > >>> layers are getting fixed recently so we should be getting there.
> > > >>
> > > >> Really? Don't forget my old patch [1] then ;)
> > > >> Still I think we should rip off all the cache stuff from ehci-hcd
> > > >> until all patches for upper layers are included. Again, this stuff
> > > >> doesn't do proper things now anyway and USB won't work with dcache
> > > >> enabled.
> > > >
> > > > Have you tested? I enabled dcache on m28 and tried asix ethernet
> > > > (needed a patch) and loading from ext2 and vfat (worked).
> > >
> > > So then we have more places that accidentially aligned to 32bytes since
> > > this does not work on TI parts which require 64byte alignment.
> >
> > Oh, this is very good it's broken. People actually started whining. Now
> > we have to wait until they start identifying the problematic places and
> > fixing them.
>
> Uh-hunh. So I guess for v2012.07 we'll build-time disable dcache for
> beagle and omap3_evm

Didn't you fix the issues?

> and leave it on for mcx and see who has time and
> hardware to fix things for v2012.10.

Or we fix it for mcx too until .07 is out ?

Best regards,
Marek Vasut