Re: [PATCH v1] dmaengine: dw: Enable runtime PM

[Viresh Kumar <viresh.kumar@linaro.org>]

On 03-11-20, 20:39, Andy Shevchenko wrote:
> When consumer requests channel power on the DMA controller device
> and otherwise on the freeing channel resources.
> 
> Note, in some cases consumer acquires channel at the ->probe() stage and
> releases it at the ->remove() stage. It will mean that DMA controller device
> will be powered during all this time if there is no assist from hardware
> to idle it. The above mentioned cases should be investigated separately
> and individually.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  drivers/dma/dw/core.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
> index 7ab83fe601ed..19a23767533a 100644
> --- a/drivers/dma/dw/core.c
> +++ b/drivers/dma/dw/core.c
> @@ -982,8 +982,11 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
>  
>  	dev_vdbg(chan2dev(chan), "%s\n", __func__);
>  
> +	pm_runtime_get_sync(dw->dma.dev);
> +
>  	/* ASSERT:  channel is idle */
>  	if (dma_readl(dw, CH_EN) & dwc->mask) {
> +		pm_runtime_put_sync_suspend(dw->dma.dev);
>  		dev_dbg(chan2dev(chan), "DMA channel not idle?\n");
>  		return -EIO;
>  	}
> @@ -1000,6 +1003,7 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
>  	 * We need controller-specific data to set up slave transfers.
>  	 */
>  	if (chan->private && !dw_dma_filter(chan, chan->private)) {
> +		pm_runtime_put_sync_suspend(dw->dma.dev);
>  		dev_warn(chan2dev(chan), "Wrong controller-specific data\n");
>  		return -EINVAL;
>  	}
> @@ -1043,6 +1047,8 @@ static void dwc_free_chan_resources(struct dma_chan *chan)
>  	if (!dw->in_use)
>  		do_dw_dma_off(dw);
>  
> +	pm_runtime_put_sync_suspend(dw->dma.dev);
> +
>  	dev_vdbg(chan2dev(chan), "%s: done\n", __func__);
>  }

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

-- 
viresh