linux-kernel - Re: [PATCH 4/4] i2c: stm32f7: use proper DMAENGINE API for termination

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Message-ID: <1b717a3f-8e2f-2e78-4509-63b04648659b@foss.st.com>
Date:   Thu, 23 Sep 2021 10:38:09 +0200
From:   Pierre Yves MORDRET <pierre-yves.mordret@...s.st.com>
To:     Alain Volmat <alain.volmat@...s.st.com>, <wsa@...nel.org>
CC:     <alexandre.torgue@...s.st.com>, <linux-i2c@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <fabrice.gasnier@...s.st.com>,
        <amelie.delaunay@...s.st.com>
Subject: Re: [PATCH 4/4] i2c: stm32f7: use proper DMAENGINE API for
 termination

Hi Alain

Look good to me

Reviewed-by: Pierre-Yves MORDRET <pierre-yves.mordret@...s.st.com>

Regards

On 9/20/21 5:21 PM, Alain Volmat wrote:
> dmaengine_terminate_all() is deprecated in favor of explicitly saying if
> it should be sync or async.  Here, we use dmaengine_terminate_sync in
> i2c_xfer and i2c_smbus_xfer handlers and rely on
> dmaengine_terminate_async within interrupt handlers
> (transmission error cases).
> dmaengine_synchronize is added within i2c_xfer and i2c_smbus_xfer handler
> to finalize terminate started in interrupt handlers.
> 
> Signed-off-by: Alain Volmat <alain.volmat@...s.st.com>
> ---
>  drivers/i2c/busses/i2c-stm32f7.c | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
> index 50d5ae81d227..66145d2b9b55 100644
> --- a/drivers/i2c/busses/i2c-stm32f7.c
> +++ b/drivers/i2c/busses/i2c-stm32f7.c
> @@ -1521,7 +1521,7 @@ static irqreturn_t stm32f7_i2c_isr_event(int irq, void *data)
>  		writel_relaxed(STM32F7_I2C_ICR_NACKCF, base + STM32F7_I2C_ICR);
>  		if (i2c_dev->use_dma) {
>  			stm32f7_i2c_disable_dma_req(i2c_dev);
> -			dmaengine_terminate_all(dma->chan_using);
> +			dmaengine_terminate_async(dma->chan_using);
>  		}
>  		f7_msg->result = -ENXIO;
>  	}
> @@ -1588,7 +1588,7 @@ static irqreturn_t stm32f7_i2c_isr_event_thread(int irq, void *data)
>  	if (!ret) {
>  		dev_dbg(i2c_dev->dev, "<%s>: Timed out\n", __func__);
>  		stm32f7_i2c_disable_dma_req(i2c_dev);
> -		dmaengine_terminate_all(dma->chan_using);
> +		dmaengine_terminate_async(dma->chan_using);
>  		f7_msg->result = -ETIMEDOUT;
>  	}
>  
> @@ -1665,7 +1665,7 @@ static irqreturn_t stm32f7_i2c_isr_error(int irq, void *data)
>  	/* Disable dma */
>  	if (i2c_dev->use_dma) {
>  		stm32f7_i2c_disable_dma_req(i2c_dev);
> -		dmaengine_terminate_all(dma->chan_using);
> +		dmaengine_terminate_async(dma->chan_using);
>  	}
>  
>  	i2c_dev->master_mode = false;
> @@ -1702,6 +1702,9 @@ static int stm32f7_i2c_xfer(struct i2c_adapter *i2c_adap,
>  						i2c_dev->adap.timeout);
>  	ret = f7_msg->result;
>  	if (ret) {
> +		if (i2c_dev->use_dma)
> +			dmaengine_synchronize(dma->chan_using);
> +
>  		/*
>  		 * It is possible that some unsent data have already been
>  		 * written into TXDR. To avoid sending old data in a
> @@ -1716,7 +1719,7 @@ static int stm32f7_i2c_xfer(struct i2c_adapter *i2c_adap,
>  		dev_dbg(i2c_dev->dev, "Access to slave 0x%x timed out\n",
>  			i2c_dev->msg->addr);
>  		if (i2c_dev->use_dma)
> -			dmaengine_terminate_all(dma->chan_using);
> +			dmaengine_terminate_sync(dma->chan_using);
>  		stm32f7_i2c_wait_free_bus(i2c_dev);
>  		ret = -ETIMEDOUT;
>  	}
> @@ -1761,6 +1764,9 @@ static int stm32f7_i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
>  					      i2c_dev->adap.timeout);
>  	ret = f7_msg->result;
>  	if (ret) {
> +		if (i2c_dev->use_dma)
> +			dmaengine_synchronize(dma->chan_using);
> +
>  		/*
>  		 * It is possible that some unsent data have already been
>  		 * written into TXDR. To avoid sending old data in a
> @@ -1774,7 +1780,7 @@ static int stm32f7_i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
>  	if (!timeout) {
>  		dev_dbg(dev, "Access to slave 0x%x timed out\n", f7_msg->addr);
>  		if (i2c_dev->use_dma)
> -			dmaengine_terminate_all(dma->chan_using);
> +			dmaengine_terminate_sync(dma->chan_using);
>  		stm32f7_i2c_wait_free_bus(i2c_dev);
>  		ret = -ETIMEDOUT;
>  		goto pm_free;
> 

-- 
--
~ Py MORDRET
--