From: Ulf Hansson <ulf.hansson@linaro.org>
To: Christoph Hellwig <hch@lst.de>
Cc: "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
Rich Felker <dalias@libc.org>, Mark Brown <broonie@kernel.org>,
Linux-sh list <linux-sh@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] mmc: mmc_spi: Allow the driver to be built when CONFIG_HAS_DMA is unset
Date: Tue, 01 Sep 2020 15:36:17 +0000 [thread overview]
Message-ID: <CAPDyKFqZXdtVokrDQvJAh-NzN0T2ayPD6MepemLEaDt1TRPduw@mail.gmail.com> (raw)
In-Reply-To: <20200901150654.GB30034@lst.de>
On Tue, 1 Sep 2020 at 17:06, Christoph Hellwig <hch@lst.de> wrote:
>
> On Tue, Sep 01, 2020 at 05:04:38PM +0200, Ulf Hansson wrote:
> > +#ifdef CONFIG_HAS_DMA
> > +static int mmc_spi_dma_alloc(struct mmc_spi_host *host)
> > +{
> > + struct spi_device *spi = host->spi;
> > + struct device *dev;
> > +
> > + if (!spi->master->dev.parent->dma_mask)
> > + return 0;
>
> I still don't think this makes sense, as the dma_mask should always
> be non-NULL here.
If that is the case, I wonder how the driver could even have worked without DMA.
Because in the existing code, host->dma_dev gets assigned to
spi->master->dev.parent->dma_mask - which seems to turn on the DMA
usage in the driver.
What am I missing?
Kind regards
Uffe
next prev parent reply other threads:[~2020-09-01 15:36 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-01 15:04 [PATCH v2] mmc: mmc_spi: Allow the driver to be built when CONFIG_HAS_DMA is unset Ulf Hansson
2020-09-01 15:06 ` Christoph Hellwig
2020-09-01 15:36 ` Ulf Hansson [this message]
2020-09-01 15:40 ` Christoph Hellwig
2020-09-02 8:31 ` Ulf Hansson
2020-09-02 13:44 ` Rich Felker
2020-09-02 15:51 ` Geert Uytterhoeven
2020-09-03 0:41 ` Rich Felker
2020-09-03 8:10 ` Ulf Hansson
2020-09-02 13:34 ` Rich Felker
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