Re: [Linux-c6x-dev] [PATCH 3/9] c6x: Provide dma_mmap_coherent() and dma_get_sgtable()

[Geert Uytterhoeven]

Marek?

On Tue, Jan 15, 2013 at 5:16 AM, Vineet Gupta
<Vineet.Gupta1@xxxxxxxxxxxx> wrote:
> On Monday 14 January 2013 09:07 PM, Mark Salter wrote:
>> On Sun, 2013-01-13 at 11:44 +0100, Geert Uytterhoeven wrote:
>>> c6x/allmodconfig (assumed):
>>>
>>> drivers/media/v4l2-core/videobuf2-dma-contig.c: In function âvb2_dc_mmapâ:
>>> drivers/media/v4l2-core/videobuf2-dma-contig.c:204: error: implicit declaration of function âdma_mmap_coherentâ
>>> drivers/media/v4l2-core/videobuf2-dma-contig.c: In function âvb2_dc_get_base_sgtâ:
>>> drivers/media/v4l2-core/videobuf2-dma-contig.c:387: error: implicit declaration of function âdma_get_sgtableâ
>>>
>>> For architectures using dma_map_ops, dma_mmap_coherent() and
>>> dma_get_sgtable() are provided in <asm-generic/dma-mapping-common.h>.
>>>
>>> C6x does not use dma_map_ops, hence it should implement them as inline
>>> stubs using dma_common_mmap() and dma_common_get_sgtable().
>>>
>>
>> So are dma_mmap_coherent() and dma_get_sgtable() part of the DMA API
>> now? I don't them in Documentation/DMA*.txt anywhere.
>>
>> Why does the default dma_common_mmap() for !CONFIG_MMU return an
>> error?
>>
>> Wouldn't it be better to provide default implementations that an arch
>> could override rather than having to patch all "no dma_map_ops"
>> architectures?
>>
>> --Mark
>>
>>
>
> Speaking for the still-reviewed ARC Port, I completely agree with Mark.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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