Re: [PATCH v2 5/7] dmaengine: dw: platform: power on device on shutdown

Vinod Koul
2015-11-26T16:57:28Z

On Thu, Nov 26, 2015 at 05:19:11PM +0200, Andy Shevchenko wrote:
> We have to call dw_dma_disable() to stop any ongoing transfer.

Ok

> On some platforms we can't do that since DMA device is powered off.

Umm, you said we have ongoing transfer which means DMA should be on..!!

> Moreover we have no
> possibility at that point to check if the platform is affected or not. That's
> why we call pm_runtime_get_sync() / pm_runtime_put() unconditionally. On the
> other hand we can't use pm_runtime_suspended() because runtime PM framework is
> not fully used by the driver.

Shouldn't that be fixed?

>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
> drivers/dma/dw/platform.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/drivers/dma/dw/platform.c b/drivers/dma/dw/platform.c
> index 68a4815..d0734e9 100644
> --- a/drivers/dma/dw/platform.c
> +++ b/drivers/dma/dw/platform.c
> @@ -239,7 +239,19 @@ static void dw_shutdown(struct platform_device *pdev)
> {
> struct dw_dma_chip *chip = platform_get_drvdata(pdev);
>
> + /*
> + * We have to call dw_dma_disable() to stop any ongoing transfer. On
> + * some platforms we can't do that since DMA device is powered off.
> + * Moreover we have no possibility to check if the platform is affected
> + * or not. That's why we call pm_runtime_get_sync() / pm_runtime_put()
> + * unconditionally. On the other hand we can't use
> + * pm_runtime_suspended() because runtime PM framework is not fully
> + * used by the driver.
> + */
> + pm_runtime_get_sync(chip->dev);
> dw_dma_disable(chip);
> + pm_runtime_put_sync_suspend(chip->dev);
> +
> clk_disable_unprepare(chip->clk);
> }
>
> --
> 2.6.2
>

--
~Vinod