On Tue, Jun 06, 2017 at 01:49:29PM +0100, Jon Hunter wrote:
> Commit edd3bdbe9db1 ("dmaengine: tegra-apb: Correct runtime-pm usage")
> added pm_runtime_get/put() calls to the tegra-apb DMA system suspend
> callbacks. Runtime PM is disabled during system suspend and so these
> APIs cannot be used. Fix the suspend handling for the tegra-apb DMA by
> moving the save and restore of the DMA register context into the
> runtime PM suspend and resume callbacks, and then use the
> pm_runtime_force_suspend/resume() APIs to invoke the runtime PM
> callbacks during system suspend.
>
> Fixes: edd3bdbe9db1 ("dmaengine: tegra-apb: Correct runtime-pm usage")
>
> Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx>
> ---
>
> Changes since V1:
> - Drop the custom suspend/resume callbacks and use
> pm_runtime_force_suspend/resume directly in SET_SYSTEM_SLEEP_PM_OPS.
>
> drivers/dma/tegra20-apb-dma.c | 50 +++++++++----------------------------------
> 1 file changed, 10 insertions(+), 40 deletions(-)
>
> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> index 3722b9d8d9fe..b9d75a54c896 100644
> --- a/drivers/dma/tegra20-apb-dma.c
> +++ b/drivers/dma/tegra20-apb-dma.c
> @@ -1494,35 +1494,7 @@ static int tegra_dma_remove(struct platform_device *pdev)
> static int tegra_dma_runtime_suspend(struct device *dev)
> {
> struct tegra_dma *tdma = dev_get_drvdata(dev);
> -
> - clk_disable_unprepare(tdma->dma_clk);
> - return 0;
> -}
> -
> -static int tegra_dma_runtime_resume(struct device *dev)
> -{
> - struct tegra_dma *tdma = dev_get_drvdata(dev);
> - int ret;
> -
> - ret = clk_prepare_enable(tdma->dma_clk);
> - if (ret < 0) {
> - dev_err(dev, "clk_enable failed: %d\n", ret);
> - return ret;
> - }
> - return 0;
> -}
> -
> -#ifdef CONFIG_PM_SLEEP
> -static int tegra_dma_pm_suspend(struct device *dev)
> -{
> - struct tegra_dma *tdma = dev_get_drvdata(dev);
> int i;
> - int ret;
> -
> - /* Enable clock before accessing register */
> - ret = pm_runtime_get_sync(dev);
> - if (ret < 0)
> - return ret;
>
> tdma->reg_gen = tdma_read(tdma, TEGRA_APBDMA_GENERAL);
> for (i = 0; i < tdma->chip_data->nr_channels; i++) {
> @@ -1543,21 +1515,21 @@ static int tegra_dma_pm_suspend(struct device *dev)
> TEGRA_APBDMA_CHAN_WCOUNT);
> }
>
> - /* Disable clock */
> - pm_runtime_put(dev);
> + clk_disable_unprepare(tdma->dma_clk);
> +
> return 0;
> }
>
> -static int tegra_dma_pm_resume(struct device *dev)
> +static int tegra_dma_runtime_resume(struct device *dev)
> {
> struct tegra_dma *tdma = dev_get_drvdata(dev);
> - int i;
> - int ret;
> + int i, ret;
>
> - /* Enable clock before accessing register */
> - ret = pm_runtime_get_sync(dev);
> - if (ret < 0)
> + ret = clk_prepare_enable(tdma->dma_clk);
> + if (ret < 0) {
> + dev_err(dev, "clk_enable failed: %d\n", ret);
> return ret;
> + }
>
> tdma_write(tdma, TEGRA_APBDMA_GENERAL, tdma->reg_gen);
> tdma_write(tdma, TEGRA_APBDMA_CONTROL, 0);
> @@ -1582,16 +1554,14 @@ static int tegra_dma_pm_resume(struct device *dev)
> (ch_reg->csr & ~TEGRA_APBDMA_CSR_ENB));
> }
>
> - /* Disable clock */
> - pm_runtime_put(dev);
> return 0;
> }
> -#endif
>
> static const struct dev_pm_ops tegra_dma_dev_pm_ops = {
> SET_RUNTIME_PM_OPS(tegra_dma_runtime_suspend, tegra_dma_runtime_resume,
> NULL)
> - SET_SYSTEM_SLEEP_PM_OPS(tegra_dma_pm_suspend, tegra_dma_pm_resume)
> + SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> + pm_runtime_force_resume)
Is that even necessary? I thought runtime PM was going to be triggered
for system sleep anyway, but it looks like there are other examples of
this usage, so maybe I'm mistaken.
Thierry
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