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Re: [PATCH] spi: mediatek: Manually set dma_ops for spi_master device

From Mark Brown <broonie@kernel.org>
Newsgroups linux.kernel
Subject Re: [PATCH] spi: mediatek: Manually set dma_ops for spi_master device
Date 2017-01-27 14:40 +0100
Message-ID <t4eUX-4Ja-43@gated-at.bofh.it> (permalink)
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On Thu, Jan 26, 2017 at 09:26:13AM -0800, Dmitry Torokhov wrote:

> OTOH the full buffer used by cros ec *is* DMA-safe (allocated with
> kmalloc), it is that cors ec uses it at offset while transferring data
> piece by piece. Do we want to support this?

I'm not sure the complexity is worth it as a general feature, I worry
about the cost of worrying about cutting the transaction up to include a
PIO portion.  That said that's just a gut feeling, if there were a
sufficiently simple/nice implementation it'd definitely avoid bugs.

To me part of DMA safety is the alignment restrictions.

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[PATCH] spi: mediatek: Manually set dma_ops for spi_master device Daniel Kurtz <djkurtz@chromium.org> - 2017-01-24 14:30 +0100
  Re: [PATCH] spi: mediatek: Manually set dma_ops for spi_master device Robin Murphy <robin.murphy@arm.com> - 2017-01-24 16:20 +0100
    Re: [PATCH] spi: mediatek: Manually set dma_ops for spi_master device Daniel Kurtz <djkurtz@chromium.org> - 2017-01-25 11:30 +0100
      Re: [PATCH] spi: mediatek: Manually set dma_ops for spi_master device Mark Brown <broonie@kernel.org> - 2017-01-25 13:40 +0100
      Re: [PATCH] spi: mediatek: Manually set dma_ops for spi_master device Robin Murphy <robin.murphy@arm.com> - 2017-01-25 19:00 +0100
        Re: [PATCH] spi: mediatek: Manually set dma_ops for spi_master device Daniel Kurtz <djkurtz@chromium.org> - 2017-01-26 17:30 +0100
          Re: [PATCH] spi: mediatek: Manually set dma_ops for spi_master device Dmitry Torokhov <dtor@chromium.org> - 2017-01-26 17:50 +0100
            Re: [PATCH] spi: mediatek: Manually set dma_ops for spi_master device Mark Brown <broonie@kernel.org> - 2017-01-26 18:10 +0100
              Re: [PATCH] spi: mediatek: Manually set dma_ops for spi_master device Dmitry Torokhov <dtor@chromium.org> - 2017-01-26 18:30 +0100
                Re: [PATCH] spi: mediatek: Manually set dma_ops for spi_master device Mark Brown <broonie@kernel.org> - 2017-01-27 14:40 +0100
            Re: [PATCH] spi: mediatek: Manually set dma_ops for spi_master device Daniel Kurtz <djkurtz@chromium.org> - 2017-01-26 18:10 +0100
  Re: [PATCH] spi: mediatek: Manually set dma_ops for spi_master device Mark Brown <broonie@kernel.org> - 2017-01-24 16:50 +0100

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