mmc: sdio: support suspend/resume while runtime suspended (ed2a9785) · Commits · 戴 / test

Bring SDIO devices back to full power before their suspend handler is invoked. Doing so ensures that SDIO suspend/resume semantics are maintained (drivers still get to decide whether their card should be removed or kept during system suspend, and at what power state), and that SDIO suspend/resume execution paths are unchanged. This is achieved by resuming a runtime-suspended SDIO device in its ->prepare() PM callback (similary to the PCI subsystem). Since the PM core always increments the run-time usage counter before calling the ->prepare() callback and decrements it after calling the ->complete() callback, it is guaranteed that when the system will come out of suspend, our device's power state will reflect its runtime PM usage counter. Signed-off-by:

Ohad Ben-Cohen <ohad@wizery.com> Tested-by:

Luciano Coelho <luciano.coelho@nokia.com> Signed-off-by:

Chris Ball <cjb@laptop.org>

drivers/mmc/core/sdio_bus.c

+29 −0

Original line number	Diff line number	Diff line
		@@ -189,12 +189,41 @@ out:

		#ifdef CONFIG_PM_RUNTIME

		static int sdio_bus_pm_prepare(struct device *dev)
		{
		/*
		* Resume an SDIO device which was suspended at run time at this
		* point, in order to allow standard SDIO suspend/resume paths
		* to keep working as usual.
		*
		* Ultimately, the SDIO driver itself will decide (in its
		* suspend handler, or lack thereof) whether the card should be
		* removed or kept, and if kept, at what power state.
		*
		* At this point, PM core have increased our use count, so it's
		* safe to directly resume the device. After system is resumed
		* again, PM core will drop back its runtime PM use count, and if
		* needed device will be suspended again.
		*
		* The end result is guaranteed to be a power state that is
		* coherent with the device's runtime PM use count.
		*
		* The return value of pm_runtime_resume is deliberately unchecked
		* since there is little point in failing system suspend if a
		* device can't be resumed.
		*/
		pm_runtime_resume(dev);

		return 0;
		}

		static const struct dev_pm_ops sdio_bus_pm_ops = {
		SET_RUNTIME_PM_OPS(
		pm_generic_runtime_suspend,
		pm_generic_runtime_resume,
		pm_generic_runtime_idle
		)
		.prepare = sdio_bus_pm_prepare,
		};

		#define SDIO_PM_OPS_PTR (&sdio_bus_pm_ops)

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