Re: [PATCH 2/2] usb: host: xhci: using dma pool for scratchpad buffer

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On Thu, Mar 30, 2017 at 11:29:57AM +0300, Mathias Nyman wrote:
> >>
> >>the other way around. First you patch dma_alloc_coherent() to
> >>dma_zalloc_coherent() and that could go in during the -rc and possibly
> >>get a stable tag, since spec requires kernel to zero the memory area.
> >>
> >>--
> >>balbi
> >
> >In fact, it fixes two things at spec, the other thing is the scratchpad
> >buffer needs to be page_size boundary. I will send these two fixes
> >first.
> >
> 
> If I remember correctly dma_alloc_coherent() takes care of proper alignment
> and won't cross the boundary
> 

Sorry to reply late.

The dma_alloc_coherent design is different per platform, and both the
code include/linux/dma-mapping.h and doc Documentation/DMA-API.txt
does not mention boundary and alignment.

-- 

Best Regards,
Peter Chen
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