[U-Boot] [PATCH] smsc95xx: align buffers to cache line size

Marek Vasut marek.vasut at gmail.com
Tue Jul 10 17:53:28 CEST 2012


Dear Ilya Yanok,

> On Tue, Jul 10, 2012 at 1:34 PM, Marek Vasut <marek.vasut at gmail.com> wrote:
> > > > aligned to
> > > > 16 bytes for arch with 16 byte cachelines.
> > > 
> > > Yes, and this is exactly what we need.
> > > 
> > > > ALLOC_CACHE_ALIGN_BUFFER(u32, tmpbuf, 1); this stuff maybe? It'll be
> > 
> > It isn't, EHCI needs it aligned on 32 byte boundary.
> 
> It doesn't. I posted the page number with data buffer description in EHCI
> spec upper in this thread. There is no alignment requirement at all.
> Controller is fine with any address. _We_ need the buffer to be cache line
> aligned to perform cache operations safely.

You're right ... I'm starting to get this mixed with DMA. DMA, USB, caches ... 
it's starting to melt into one big goo in my head. Sorry.

> Regards, Ilya.

Best regards,
Marek Vasut


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