Re: [PATCH RFC] usb: musb: fail unaligned DMA transfers on v1.8 and above

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On Sun, Oct 31, 2010 at 12:25:59AM -0500, Gadiyar, Anand wrote:
The Inventra DMA engine in version 1.8 and later of the MUSB
controller cannot handle DMA addresses that are not aligned
to a 4 byte boundary. It ends up ignoring the last two bits
programmed in the DMA_ADDR register. This is a deliberate
design change in the controller and is documented in the
programming guide.

Earlier versions of the controller could handle these
accesses just fine.

Fail dma_channel_program if we see an unaligned address when
using the newer controllers, so that the caller can carry out
the transfer using PIO mode.
(Current callers already have this backup path in place).

Signed-off-by: Anand Gadiyar <gadiyar@xxxxxx>
Cc: Felipe Balbi <balbi@xxxxxx>
Cc: Ming Lei <tom.leiming@xxxxxxxxx>
Cc: Ajay Kumar Gupta <ajay.gupta@xxxxxx>
Cc: Mike Frysinger <vapier@xxxxxxxxxx>

please fix comment from Sergei and resend without RFC.

--
balbi
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