Re: [PATCH 4/7] spi: spi-geni-qcom: Add support for GPI dma

From: Vinod Koul <vkoul@kernel.org>
To: Mark Brown <broonie@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>,
	Wolfram Sang <wsa@kernel.org>,
	linux-arm-msm@vger.kernel.org, Andy Gross <agross@kernel.org>,
	Matthias Kaehlcke <mka@chromium.org>,
	Douglas Anderson <dianders@chromium.org>,
	Sumit Semwal <sumit.semwal@linaro.org>,
	Amit Pundir <amit.pundir@linaro.org>,
	linux-spi@vger.kernel.org, linux-i2c@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/7] spi: spi-geni-qcom: Add support for GPI dma
Date: Wed, 16 Jun 2021 14:20:45 +0530	[thread overview]
Message-ID: <YMm7ZWXnJyb8QT1u@vkoul-mobl> (raw)
In-Reply-To: <20210111163504.GD4728@sirena.org.uk>

Hi Mark,

On 11-01-21, 16:35, Mark Brown wrote:
> On Mon, Jan 11, 2021 at 08:46:48PM +0530, Vinod Koul wrote:
> 
> > +static int get_xfer_mode(struct spi_master *spi)
> > +{
> > +	struct spi_geni_master *mas = spi_master_get_devdata(spi);
> > +	struct geni_se *se = &mas->se;
> > +	int mode = GENI_SE_FIFO;
> 
> Why not use the core DMA mapping support?

Sorry I seemed to have missed replying to this one.

Looking at the code, that is ideal case. Only issue I can see is that
core DMA mapping device being used is incorrect. The core would use
ctlr->dev.parent which is the spi0 device here.

But in this case, that wont work. We have a parent qup device which is
the parent for both spi and dma device and needs to be used for
dma-mapping! 

If we allow drivers to set dma mapping device and use that, then I can
reuse the core. Let me know if that is agreeable to you and I can hack
this up. Maybe add a new member in spi_controller which is filled by
drivers in can_dma() callback?

Thanks
-- 
~Vinod