Re: [PATCH 3/4] i2c: stm32f7: stop dma transfer in case of NACK

From: Pierre Yves MORDRET
Date: Thu Sep 23 2021 - 04:37:58 EST


Hi Alain

Look good to me

Reviewed-by: Pierre-Yves MORDRET <pierre-yves.mordret@xxxxxxxxxxx>

Regards

On 9/20/21 5:21 PM, Alain Volmat wrote:
> In case of receiving a NACK, the dma transfer should be stopped
> to avoid feeding data into the FIFO.
> Also ensure to properly return the proper error code and avoid
> waiting for the end of the dma completion in case of
> error happening during the transmission.
>
> Fixes: 7ecc8cfde553 ("i2c: i2c-stm32f7: Add DMA support")
>
> Signed-off-by: Alain Volmat <alain.volmat@xxxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-stm32f7.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
> index ad3459a3bc5e..50d5ae81d227 100644
> --- a/drivers/i2c/busses/i2c-stm32f7.c
> +++ b/drivers/i2c/busses/i2c-stm32f7.c
> @@ -1493,6 +1493,7 @@ static irqreturn_t stm32f7_i2c_isr_event(int irq, void *data)
> {
> struct stm32f7_i2c_dev *i2c_dev = data;
> struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
> + struct stm32_i2c_dma *dma = i2c_dev->dma;
> void __iomem *base = i2c_dev->base;
> u32 status, mask;
> int ret = IRQ_HANDLED;
> @@ -1518,6 +1519,10 @@ static irqreturn_t stm32f7_i2c_isr_event(int irq, void *data)
> dev_dbg(i2c_dev->dev, "<%s>: Receive NACK (addr %x)\n",
> __func__, f7_msg->addr);
> 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);
> + }
> f7_msg->result = -ENXIO;
> }
>
> @@ -1533,7 +1538,7 @@ static irqreturn_t stm32f7_i2c_isr_event(int irq, void *data)
> /* Clear STOP flag */
> writel_relaxed(STM32F7_I2C_ICR_STOPCF, base + STM32F7_I2C_ICR);
>
> - if (i2c_dev->use_dma) {
> + if (i2c_dev->use_dma && !f7_msg->result) {
> ret = IRQ_WAKE_THREAD;
> } else {
> i2c_dev->master_mode = false;
> @@ -1546,7 +1551,7 @@ static irqreturn_t stm32f7_i2c_isr_event(int irq, void *data)
> if (f7_msg->stop) {
> mask = STM32F7_I2C_CR2_STOP;
> stm32f7_i2c_set_bits(base + STM32F7_I2C_CR2, mask);
> - } else if (i2c_dev->use_dma) {
> + } else if (i2c_dev->use_dma && !f7_msg->result) {
> ret = IRQ_WAKE_THREAD;
> } else if (f7_msg->smbus) {
> stm32f7_i2c_smbus_rep_start(i2c_dev);
>

--
--
~ Py MORDRET
--