[U-Boot] [PATCH v3 2/6] ehci-hcd.c, musb_core, usb.h: Add USB_DMA_MINALIGN define for cache alignment

Marek Vasut
2012-06-20T21:15:26Z

Dear Tom Rini,

> On Wed, Jun 20, 2012 at 09:00:45PM +0200, Marek Vasut wrote:
> > Dear Tom Rini,
> >
> > > The USB spec says that 32 bytes is the minimum required alignment.
> > > However on some platforms we have a larger minimum requirement for
> > > cache coherency. In those cases, use that value rather than the USB
> > > spec minimum. We add a cpp check to <usb.h> to define
> > > USB_DMA_MINALIGN and make use of it in ehci-hcd.c and musb_core.h. We
> > > cannot use MAX() here as we are not allowed to have tests inside of
> > > align(...).
> > >
> > > Cc: Marek Vasut <marex@denx.de>
> > > Signed-off-by: Tom Rini <trini@ti.com>
> > >
> > > --
> > > Changes in v2:
> > > - Move test to <usb.h>, expand comment.
> > > ---
> > >
> > > drivers/usb/host/ehci-hcd.c | 13 +++++++------
> > > drivers/usb/musb/musb_core.h | 2 +-
> > > include/usb.h | 10 ++++++++++
> > > 3 files changed, 18 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
> > > index 04300be..5a86117 100644
> > > --- a/drivers/usb/host/ehci-hcd.c
> > > +++ b/drivers/usb/host/ehci-hcd.c
> > > @@ -29,12 +29,13 @@
> > >
> > > #include "ehci.h"
> > >
> > > -int rootdev;
> > > -struct ehci_hccr *hccr; /* R/O registers, not need for volatile */
> > > -volatile struct ehci_hcor *hcor;
> > > +int rootdev __attribute__((aligned(USB_DMA_MINALIGN)));
> > > +/* R/O registers, not need for volatile */
> > > +struct ehci_hccr *hccr __attribute__((aligned(USB_DMA_MINALIGN)));
> > > +volatile struct ehci_hcor *hcor
> > > __attribute__((aligned(USB_DMA_MINALIGN)));
> >
> > ^ these need to be aligned too?
>
> Yes, these were the first and easy to spot ones in the cache flush
> messages, I would swear.

hcor and hccr are register locations though ... so it's pretty weird.

Best regards,
Marek Vasut