From: Arnd Bergmann <arnd@arndb.de>
To: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexandre Courbot <acourbot@nvidia.com>,
        Ulf Hansson <ulf.hansson@linaro.org>, linux-mmc@vger.kernel.org,
        linux-kernel@vger.kernel.org, gnurou@gmail.com
Subject: Re: [PATCH v4 1/3] mmc: sdhci: Set DMA mask when adding host
Date: Wed, 16 Mar 2016 10:07:01 +0100
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On Wednesday 16 March 2016 10:43:33 Adrian Hunter wrote:
> > +
> > +     /* 32-bit mask as default & fallback */
> > +     if (ret) {
> > +             ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
> 
> What happens if device enumeration (e.g. of_dma_configure) has already set a
> more restrictive DMA mask?
> 
> 

In this case, dma_set_mask_and_coherent() is supposed to check the
bus properties settings again and fail dma_set_mask_and_coherent().

We currently don't do that on ARM, which is a bug.

	Arnd