Re: [PATCH] sparc32: Page align size in arch_dma_alloc

[Christoph Hellwig]

On Wed, Sep 08, 2021 at 09:48:22AM +0200, Andreas Larsson wrote:
> Commit 53b7670e5735 ("sparc: factor the dma coherent mapping into
> helper") lost the page align for the calls to dma_make_coherent and
> srmmu_unmapiorange. The latter cannot handle a non page aligned len
> argument.
> 
> Signed-off-by: Andreas Larsson <andreas@xxxxxxxxxxx>

Looks good,

Reviewed-by: Christoph Hellwig <hch@xxxxxx>

Andreas - while I've got your attention:  I've been looking into fully
converting sparc32 to the generic DMA code.  Do you have any
documentation for the Leon cache handling in dma_make_coherent,
and more importantly how that applies to the dma coherent handling?
I could see how a flush might be required for the streaming DMA mappings,
that is mapping normal cached memory for I/O.  But for the coherent
allocations which can be accessed from the device and the cpu without
another DMA mapping call this seems really strange.