Thread (14 messages) 14 messages, 5 authors, 2019-08-24

Re: [PATCH 4/6] dma-mapping: remove arch_dma_mmap_pgprot

From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: 2019-08-16 07:43:54
Also in: linux-iommu, linux-mips, linuxppc-dev, lkml

On Fri, Aug 16, 2019 at 9:19 AM Christoph Hellwig [off-list ref] wrote:
arch_dma_mmap_pgprot is used for two things:

 1) to override the "normal" uncached page attributes for mapping
    memory coherent to devices that can't snoop the CPU caches
 2) to provide the special DMA_ATTR_WRITE_COMBINE semantics on older
    arm systems

Replace one with the pgprot_dmacoherent macro that is already provided
by arm and much simpler to use, and lift the DMA_ATTR_WRITE_COMBINE
handling to common code with an explicit arch opt-in.

Signed-off-by: Christoph Hellwig <hch@lst.de>
 arch/m68k/Kconfig                  |  1 -
 arch/m68k/include/asm/pgtable_mm.h |  3 +++
 arch/m68k/kernel/dma.c             |  3 +--
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

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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