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

Marek Vasut
2012-07-08T18:51:35Z

Dear Ilya Yanok,

> Hi Marek,
>
> On Sun, Jul 8, 2012 at 7:08 AM, Marek Vasut <marex@denx.de> wrote:
>
> [...]
>
> diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
>
> > index 04300be..5199560 100644
> > --- a/drivers/usb/host/ehci-hcd.c
> > +++ b/drivers/usb/host/ehci-hcd.c
> > @@ -34,7 +34,10 @@ struct ehci_hccr *hccr; /* R/O registers, not
> > need for volatile */
> >
> > volatile struct ehci_hcor *hcor;
> >
> > static uint16_t portreset;
> >
> > -static struct QH qh_list __attribute__((aligned(32)));
> > +DEFINE_CACHE_ALIGN_BUFFER(struct QH, qh_list, 1);
>
> This will align on ARCH_DMA_MINALIGN, not USB_DMA_MINALIGN. In case of
> ARCH_DMA_MINALIGN < 32 we will loose the 32-byte alignment required by USB
> spec.

That's true -- maybe we should create ALLOC_ALIGN_BUFFER() and
ALLOC_CACHE_ALIGN_BUFFER() to be a special case of it ?

> The same with other buffers. Otherwise looks great.
>
> Regards, Ilya.

Best regards,
Marek Vasut