On 4 February 2014 20:22, Kevin Hilman <khilman@xxxxxxxxxx> wrote:
> Ulf Hansson <ulf.hansson@xxxxxxxxxx> writes:
>
>> Due to the available runtime PM callbacks, we are now able to put our
>> device into low power state at system suspend.
>>
>> Earlier we could not accomplish this without trusting a power domain
>> for the device to take care of it. Now we are able to cope with
>> scenarios both with and without a power domain.
>>
>> Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
>> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
>> ---
>> drivers/mmc/host/mmci.c | 45 +++++++++++++++++++++++++--------------------
>> 1 file changed, 25 insertions(+), 20 deletions(-)
>>
>> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
>> index c88da1c..074e0cb 100644
>> --- a/drivers/mmc/host/mmci.c
>> +++ b/drivers/mmc/host/mmci.c
>> @@ -1723,33 +1723,38 @@ static int mmci_remove(struct amba_device *dev)
>> return 0;
>> }
>>
>> -#ifdef CONFIG_SUSPEND
>> -static int mmci_suspend(struct device *dev)
>> +#ifdef CONFIG_PM_SLEEP
>> +static int mmci_suspend_late(struct device *dev)
>> {
>> - struct amba_device *adev = to_amba_device(dev);
>> - struct mmc_host *mmc = amba_get_drvdata(adev);
>> + int ret = 0;
>>
>> - if (mmc) {
>> - struct mmci_host *host = mmc_priv(mmc);
>> - pm_runtime_get_sync(dev);
>> - writel(0, host->base + MMCIMASK0);
>> - }
>> + if (pm_runtime_status_suspended(dev))
>> + return 0;
>>
>> - return 0;
>> + if (dev->pm_domain && dev->pm_domain->ops.runtime_suspend)
>> + ret = dev->pm_domain->ops.runtime_suspend(dev);
>> + else
>> + ret = dev->bus->pm->runtime_suspend(dev);
>> +
>> + if (!ret)
>> + pm_runtime_set_suspended(dev);
>
> Isn't this basically open-coding pm_runtime_suspend()...
It is similar, but with once big difference.
Since the PM core prevents pm_runtime_suspend() from invoking our
->runtime_suspend callback during system suspend (it does so by
invoking pm_runtime_get_sync() before starting the suspend sequence),
we then need to make the driver handle that by itself.
>
>> + return ret;
>> }
>>
>> -static int mmci_resume(struct device *dev)
>> +static int mmci_resume_early(struct device *dev)
>> {
>> - struct amba_device *adev = to_amba_device(dev);
>> - struct mmc_host *mmc = amba_get_drvdata(adev);
>> + int ret = 0;
>>
>> - if (mmc) {
>> - struct mmci_host *host = mmc_priv(mmc);
>> - writel(MCI_IRQENABLE, host->base + MMCIMASK0);
>> - pm_runtime_put(dev);
>> - }
>> + if (pm_runtime_status_suspended(dev))
>> + return 0;
>>
>> - return 0;
>> + if (dev->pm_domain && dev->pm_domain->ops.runtime_resume)
>> + ret = dev->pm_domain->ops.runtime_resume(dev);
>> + else
>> + ret = dev->bus->pm->runtime_resume(dev);
>> +
>> + return ret;
>
> ...and this is pm_runtime_resume()? (though both terribly simplified.)
Correct, but again with a big difference. See comment above.
>
> This is starting to show that building with PM_SLEEP but not PM_RUNTIME
> is going to force open-coding a lot of stuff that the runtime PM
> framework already provides. So either we need some helper functions so
> we're not sprinkling manual calls to bus/pm_domain callbacks all over
I have send a patch a while ago for the PM core, that tried to
implement something similar like this, I wasn't accepted. I will
follow up on that asap.
Still, do you think we could go ahead with this patch? If/when we can
get an acceptance for a PM runtime helper function in the PM core, we
can easily convert to use it later on.
> the place, or maybe where we need to go is have a way for platforms that
> really are "runtime PM centric" to declare that even PM_SLEEP depends on
> PM_RUNTIME.
>
> I'm trying to thing of a good reason to not make PM_SLEEP depend on
> PM_RUNTIME for platforms like this.
This wont help. The PM core will still prevent the runtime_suspend
callback from being invoked during system suspend.
Kind regards
Ulf Hansson
>
> Kevin
>
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