Re: [PATCH 2/2] i2c: qcom-geni: Provide an option to disable DMA processing

From: Lee Jones <lee.jones@linaro.org>
To: Wolfram Sang <wsa@the-dreams.de>
Cc: alokc@codeaurora.org, agross@kernel.org, robh+dt@kernel.org,
	mark.rutland@arm.com, bjorn.andersson@linaro.org,
	linux-i2c@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	devicetree@vger.kernel.org, vkoul@kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] i2c: qcom-geni: Provide an option to disable DMA processing
Date: Thu, 5 Sep 2019 10:28:16 +0100	[thread overview]
Message-ID: <20190905092816.GD26880@dell> (raw)
In-Reply-To: <20190905091800.GD1157@kunai>

On Thu, 05 Sep 2019, Wolfram Sang wrote:

> 
> > Fixes: 8bc529b25354 ("soc: qcom: geni: Add support for ACPI")
> 
> Are you sure? From visual inspection, I don't see a correlation between
> this commit and the fix here.

This patch should have been part of the commit, or at the very least,
part of the set, alluded to above.  Unfortunately, I was carrying
Bjorn's hack which simply returned early from geni_se_rx_dma_prep()
with an error, so it masked the issue.

> > Signed-off-by: Lee Jones <lee.jones@linaro.org>
> > Reviewed-by: Vinod Koul <vkoul@kernel.org>
> > ---
> >  drivers/i2c/busses/i2c-qcom-geni.c | 14 ++++++++++----
> >  1 file changed, 10 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
> > index a89bfce5388e..8822dea82980 100644
> > --- a/drivers/i2c/busses/i2c-qcom-geni.c
> > +++ b/drivers/i2c/busses/i2c-qcom-geni.c
> > @@ -353,13 +353,16 @@ static void geni_i2c_tx_fsm_rst(struct geni_i2c_dev *gi2c)
> >  static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
> >  				u32 m_param)
> >  {
> > +	struct device_node *np = gi2c->se.dev->of_node;
> >  	dma_addr_t rx_dma;
> >  	unsigned long time_left;
> > -	void *dma_buf;
> > +	void *dma_buf = NULL;
> >  	struct geni_se *se = &gi2c->se;
> >  	size_t len = msg->len;
> >  
> > -	dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
> > +	if (!of_property_read_bool(np, "qcom,geni-se-no-dma"))
> > +		dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
> > +
> >  	if (dma_buf)
> >  		geni_se_select_mode(se, GENI_SE_DMA);
> >  	else
> > @@ -392,13 +395,16 @@ static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
> >  static int geni_i2c_tx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
> >  				u32 m_param)
> >  {
> > +	struct device_node *np = gi2c->se.dev->of_node;
> >  	dma_addr_t tx_dma;
> >  	unsigned long time_left;
> > -	void *dma_buf;
> > +	void *dma_buf = NULL;
> >  	struct geni_se *se = &gi2c->se;
> >  	size_t len = msg->len;
> >  
> > -	dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
> > +	if (!of_property_read_bool(np, "qcom,geni-se-no-dma"))
> > +		dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
> > +
> >  	if (dma_buf)
> >  		geni_se_select_mode(se, GENI_SE_DMA);
> >  	else

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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