[U-Boot] [PATCH 2/2] ehci-hcd.c, musb_core, usb.h: Add USB_DMA_MINALIGN define for cache alignment

[Marek Vasut <marex@denx.de>]

Dear Ilya Yanok,

> Hi Marek,
> 
> On Sun, Jul 8, 2012 at 7:08 AM, Marek Vasut <marex@denx.de> wrote:
> > -       /* Invalidate the memory area occupied by buffer */
> > -       invalidate_dcache_range(((uint32_t)buffer & ~31),
> > -               ((uint32_t)buffer & ~31) + roundup(length, 32));
> > +       /*
> > +        * Invalidate the memory area occupied by buffer
> > +        * Don't try to fix the buffer alignment, if it isn't properly
> > +        * aligned it's upper layer's fault so let
> > invalidate_dcache_range()
> > +        * vow about it. But we have to fix the length as it's actual
> > +        * transfer length and can be unaligned. This is potentially
> > +        * dangerous operation, it's responsibility of the calling
> > +        * code to make sure enough space is reserved.
> > +        */
> > +       invalidate_dcache_range((uint32_t)buffer,
> > +               ALIGN_END_ADDR(u8, buffer, length));
> 
> We shouldn't use ALIGN_END_ADDR here. This can lead to strange results on
> systems with ARCH_DMA_MINALIGN < 32.

Good point, ALIGN_END_ADDR should align it to max(32, length) ?

> Regards, Ilya.

Best regards,
Marek Vasut