On Mon, Apr 23, 2012 at 7:57 PM, Tony Lindgren <[email protected]> wrote:
> * Russell King - ARM Linux <[email protected]> [120423 07:22]:
>> On Fri, Apr 20, 2012 at 03:22:33PM -0700, Tony Lindgren wrote:
>> > * Russell King <[email protected]> [120418 03:14]:
>> > > Using coherent DMA memory with the OMAP DMA engine results in
>> > > unpredictable behaviour due to memory ordering issues; as things stand,
>> > > there is no guarantee that data written to coherent DMA memory will be
>> > > visible to the DMA hardware.
>> > >
>> > > This is because the OMAP dma_write() accessor contains no barriers,
>> > > necessary on ARMv6 and above. The effect of this can be seen in comments
>> > > in the OMAP serial driver, which incorrectly talks about cache flushing
>> > > for the coherent DMA stuff.
>> > >
>> > > Rather than adding barriers to the accessors, add it in the DMA support
>> > > code just before we enable DMA, and just after we disable DMA. This
>> > > avoids having barriers for every DMA register access.
>> > >
>> > > Signed-off-by: Russell King <[email protected]>
>> >
>> > Acked-by: Tony Lindgren <[email protected]>
>>
>> Would you like me to push this upstream on my next -rc push (with a
>> stable tag?)
>
> Yes sounds good to me.
>
FWIW,
Acked-by: Santosh Shilimkar <[email protected]>
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