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

[Tom Rini]

On Wed, Jun 20, 2012 at 11:15:26PM +0200, Marek Vasut wrote:
> 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 at denx.de>
> > > > Signed-off-by: Tom Rini <trini at 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.

OK, now that I look harder at the messages, doing that is only masking a
problem.  At issue (from u-boot.map):
 .bss           0x801586c0      0x1c0 drivers/usb/host/libusb_host.o
                0x80158860                hcor
And a message of:
ERROR: v7_dcache_inval_range - stop address is not aligned - 0x9ffbc860
Using 'bdinfo' to see reloc offset gives us hcor, but _end_ not start
means it's something within the anonymous part of the bss and padding
hcor out just masks the real problem.  I'll resubmit a v4 shortly.
Thanks!

-- 
Tom