[U-Boot] [PATCH] ehci-hcd.c, musb_core, usb.h: Add USB_DMA_MINALIGN define for cache alignment

[Marek Vasut]

Dear Ilya Yanok,

> Hi Marek,
> 
> On Thu, Jul 5, 2012 at 11:58 PM, Marek Vasut <marex at denx.de> wrote:
> > > Yep. I even thought about this but decided not to do... can't recall
> > > why. Now I think it's really a good idea.
> > > 
> > > > Maybe we should create DEFINE_ALIGNED_VARIABLE as a common.h macro?
> > 
> > Like what's in common.h -- ALLOC_CACHE_ALIGN_BUFFER ?
> 
> Yes, but for static variables and not hard-bound to ARCH_DMA_MINALIGN.

Good idea :)

> > > Hm.. Maybe. Ideas? ;) Actually I also thought about moving all this
> > > stuff to a single proper aligned buffer and do flush/invalidate for a
> > > whole buffer at once. It can save us some space... but it's BSS
> > > anyway... Don't know if it's worth it...
> > 
> > But if you copy stuff back and forth, it'll cause performance hit.
> 
> No, you talk about full bounce-buffering support and meant only one big
> buffer for internal structs.

Sure, but the internal structs can be aligned on their own, so there's no need 
for a buffer.

> Regards, Ilya.

Best regards,
Marek Vasut