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SubjectRe: [PATCH 1/4] i2c: imx: Fix reinit_completion() use
Cc += Yuan Yao who authored DMA support and the NXP team.

On Wed, May 23, 2018 at 11:56:20AM +0200, Esben Haabendal wrote:
> From: Esben Haabendal <eha@deif.com>
>
> Make sure to call reinit_completion() before dma is started to avoid race
> condition where reinit_compleition() is called after complete() and before

s/compleition/completion/

> wait_for_completion_timeout().

Is this a theoretical problem, or did it trigger on your side?

> Signed-off-by: Esben Haabendal <eha@deif.com>
Fixes: ce1a78840ff7 ("i2c: imx: add DMA support for freescale i2c driver")
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

> ---
> drivers/i2c/busses/i2c-imx.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index d7267dd9c7bf..6fca5e64cffb 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -377,6 +377,7 @@ static int i2c_imx_dma_xfer(struct imx_i2c_struct *i2c_imx,
> goto err_desc;
> }
>
> + reinit_completion(&dma->cmd_complete);
> txdesc->callback = i2c_imx_dma_callback;
> txdesc->callback_param = i2c_imx;
> if (dma_submit_error(dmaengine_submit(txdesc))) {
> @@ -631,7 +632,6 @@ static int i2c_imx_dma_write(struct imx_i2c_struct *i2c_imx,
> * The first byte must be transmitted by the CPU.
> */
> imx_i2c_write_reg(msgs->addr << 1, i2c_imx, IMX_I2C_I2DR);
> - reinit_completion(&i2c_imx->dma->cmd_complete);
> time_left = wait_for_completion_timeout(
> &i2c_imx->dma->cmd_complete,
> msecs_to_jiffies(DMA_TIMEOUT));
> @@ -690,7 +690,6 @@ static int i2c_imx_dma_read(struct imx_i2c_struct *i2c_imx,
> if (result)
> return result;
>
> - reinit_completion(&i2c_imx->dma->cmd_complete);
> time_left = wait_for_completion_timeout(
> &i2c_imx->dma->cmd_complete,
> msecs_to_jiffies(DMA_TIMEOUT));

Best regards
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |

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