On 06/06/17 15:48, Thierry Reding wrote:
> * PGP Signed by an unknown key
>
> 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.
Yes this is necessary. No RPM is not automatically trigger by system
suspend AFAICT.
Cheers
Jon
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