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

Ilya Yanok
2012-07-15T08:55:49Z

Dear Marek,

On Sun, Jul 15, 2012 at 12:07 PM, Marek Vasut <marex@denx.de> wrote:

> > > @@ -207,8 +210,8 @@ static int
> > >
> > > ehci_submit_async(struct usb_device *dev, unsigned long pipe, void
> > >
> > > *buffer,
> > >
> > > int length, struct devrequest *req)
> > >
> > > {
> > >
> > > - static struct QH qh __attribute__((aligned(32)));
> > > - static struct qTD qtd[3] __attribute__((aligned (32)));
> > > + ALLOC_CACHE_ALIGN_BUFFER(struct QH, qh, 1);
> >
> > Somehow this doesn't work being allocated on stack... I assumed that this
> > was declared as static just to use __attribute__((aligned))...
>
> Not really ... but then, we have indeed a problem here. It was probably
> declared
> static to preserve the contents of these variables across the the calls of
> this
> function. Sigh, the USB code is really bloody :-/
>

Hm.. no, I don't think it's about contents... Look, there are memset()
calls straight in the beginning of the function. It looks like it's about
qh address: I tried debugging it a bit and it seems to work until qh has
the same address and break when the address eventually changes.

> Ilya, can you try pulling these out of the function?
>

I can but what for? Are there any differences (except for scope) declaring
statics inside or outside function? As I said declaring qh static (with
DEFINE_CACHE_ALIGN_BUFFER) works but...

Regards, Ilya.