Re: [PATCH 4/4] mips: dma: Add cma support

From: Zubair Lutfullah Kakakhel
Date: Thu Jul 17 2014 - 05:17:55 EST




On 16/07/14 17:39, Michal Nazarewicz wrote:
> On Wed, Jul 16 2014, Zubair Lutfullah Kakakhel <Zubair.Kakakhel@xxxxxxxxxx> wrote:
>> Adds cma support to the mips architecture.
>>
>> cma uses memblock. However, mips uses bootmem.
>
> Does cma_early_percent_memory work correctly then?
>

Yes it does. All memblock functions work. And this is before bootmem
is informed.

>> bootmem is informed about any regions reserved by memblock
>
> Alternatively maybe it would make sense to create a new definition of
> dma_contiguous_reserve_area that uses bootmem and choose it based on
> some CONFIG_CMA_USE_BOOTMEM which would be selected by MIPS.
>

Telling bootmem takes only 3 lines.

Adding CONFIG_CMA_USE_BOOTMEM would add more functions and maintenance overhead.
And it will basically do the same thing.
Reserve memory. And tell the bootmem allocator.

>> dma api is modified to use cma reserved memory regions when available
>>
>> Tested using cma_test. cma_test is a simple driver that assigns blocks
>> of memory from cma reserved sections.
>>
>> Signed-off-by: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@xxxxxxxxxx>
>
> Acked-by: Michal Nazarewicz <mina86@xxxxxxxxxx>

Thank-you

ZubairLK
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