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From:   Masahiro Yamada <yamada.masahiro@socionext.com>
Date:   Wed, 28 Aug 2019 19:53:40 +0900
Message-ID: <CAK7LNAQ_nQcBt=xH1-h+=co85mTxFgbe+_46Gu4LaNsDSm+kYA@mail.gmail.com>
Subject: Re: [PATCH v2 2/2] dma-contiguous: Use fallback alloc_pages for
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To:     Christoph Hellwig <hch@lst.de>
Cc:     Nicolin Chen <nicoleotsuka@gmail.com>,
        linux-mmc <linux-mmc@vger.kernel.org>,
        Ulf Hansson <ulf.hansson@linaro.org>,
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        Robin Murphy <robin.murphy@arm.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>, vdumpa@nvidia.com,
        Russell King <linux@armlinux.org.uk>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
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Hi Christoph,

On Tue, Aug 27, 2019 at 8:55 PM Christoph Hellwig <hch@lst.de> wrote:
>
> On Tue, Aug 27, 2019 at 06:03:14PM +0900, Masahiro Yamada wrote:
> > Yes, this makes my driver working again
> > when CONFIG_DMA_CMA=y.
> >
> >
> > If I apply the following, my driver gets back working
> > irrespective of CONFIG_DMA_CMA.
>
> That sounds a lot like the device simply isn't 64-bit DMA capable, and
> previously always got CMA allocations under the limit it actually
> supported.  I suggest that you submit this quirk to the mmc maintainers.


I tested v5.2 and my MMC host controller works with
dma_address that exceeds 32-bit physical address.

So, I believe my MMC device is 64-bit DMA capable.

I am still looking into the code
to find out what was changed.


--
Best Regards
Masahiro Yamada