[PATCH 1/3] spi/qspi: Add memory mapped read support.

[Trent Piepho]

On Thu, Oct 17, 2013 at 9:06 PM, Sourav Poddar <sourav.poddar at ti.com> wrote:
> On Friday 18 October 2013 05:12 AM, Mark Brown wrote:
>>> Are you looking for comparison between  read_via_dma() v/s memcpy() ?
>>
>> No, I'm looking for a comparison of normal SPI mode (which I'd have
>> expected to DMA) and the memcpy() mode.
>>
>>> If yes, then unfortunately we are bit constrained because our controller
>>> does not support DMA. So, we have to depend on CPU based memcpy()
>>> only. However, use of DMA can be added as an independent patch on
>>> top of this CASE-2 patch.
>>
>> However if the controller can't DMA at all then that's not going to be
>> possible...  am I understanding you correctly that normal SPI can't DMA?
>
> Yes, you are correct, the normal SPI cant DMA.

Hardware limitation or driver limitation?  Adding DMA support to the
driver might be much more useful than adding memory mapped read
support.