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

From: Marek Vasut <marex@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 2/2] ehci-hcd.c, musb_core, usb.h: Add USB_DMA_MINALIGN define for cache alignment
Date: Sun, 8 Jul 2012 20:51:35 +0200	[thread overview]
Message-ID: <201207082051.35777.marex@denx.de> (raw)
In-Reply-To: <CAA3CPjX7=sOptffYVf9WBfZr7s0pV06y05pQ3v1cLXvdg9qb2w@mail.gmail.com>

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