On Tue, Oct 23, 2012 at 12:26:31AM -0700, Marek Vasut wrote:
> Dear Allen Martin,
>
> > Change usb_kbd driver to obey alignment requirements for USB DMA on
> > the buffer used for data transfer. This is necessary for
> > architectures that enable dcache and enable USB DMA.
> >
> > Signed-off-by: Allen Martin <amar...@nvidia.com>
> > ---
> > common/usb_kbd.c | 8 ++++----
> > 1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/common/usb_kbd.c b/common/usb_kbd.c
> > index 19f01db..57928d9 100644
> > --- a/common/usb_kbd.c
> > +++ b/common/usb_kbd.c
> > @@ -106,15 +106,15 @@ static const unsigned char usb_kbd_num_keypad[] = {
> > (USB_KBD_NUMLOCK | USB_KBD_CAPSLOCK | USB_KBD_SCROLLLOCK)
> >
> > struct usb_kbd_pdata {
> > + uint8_t new[8];
> > + uint8_t old[8];
> > +
>
> Some comment about the alignment won't hurt.
Good idea.
>
> > uint32_t repeat_delay;
> >
> > uint32_t usb_in_pointer;
> > uint32_t usb_out_pointer;
> > uint8_t usb_kbd_buffer[USB_KBD_BUFFER_LEN];
> >
> > - uint8_t new[8];
> > - uint8_t old[8];
> > -
> > uint8_t flags;
> > };
> >
> > @@ -426,7 +426,7 @@ static int usb_kbd_probe(struct usb_device *dev,
> > unsigned int ifnum)
> >
> > USB_KBD_PRINTF("USB KBD: found set protocol...\n");
> >
> > - data = malloc(sizeof(struct usb_kbd_pdata));
> > + data = memalign(USB_DMA_MINALIGN, sizeof(struct usb_kbd_pdata));
>
> Don't we have ALLOC_CACHE_ALIGN_BUFFER and such stuff in include/common.h for
> this purpose ?
There seems to be some discrepency here, because ehci-hcd.c uses
USB_DMA_MINALIGN for all cache operations, which may or may not be the
same as ARCH_DMA_MINALIGN, see usb.h:
/*
* The EHCI spec says that we must align to at least 32 bytes.
However,
* some platforms require larger alignment.
*/
#if ARCH_DMA_MINALIGN > 32
#define USB_DMA_MINALIGN ARCH_DMA_MINALIGN
#else
#define USB_DMA_MINALIGN 32
#endif
For tegra this is fine, because ARCH_DMA_MINALIGN > 32, but grepping
through header files, I see a few:
#define ARCH_DMA_MINALIGN 16
which will definately break. It looks like all other usb class
drivers use ALLOC_CACHE_ALIGN_BUFFER() though, so for consistency the
usb keyboard driver probably should too, but it seems like a potential
problem.
>
> > if (!data) {
> > printf("USB KBD: Error allocating private data\n");
> > return 0;
>
> Best regards,
> Marek Vasut
-Allen
--
nvpublic
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