From ed2a9785942b0986ac858f3f48d7fc5f7c7183de Mon Sep 17 00:00:00 2001 From: Ohad Ben-Cohen Date: Sat, 2 Oct 2010 13:54:13 +0200 Subject: [PATCH] mmc: sdio: support suspend/resume while runtime suspended 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 Tested-by: Luciano Coelho Signed-off-by: Chris Ball --- drivers/mmc/core/sdio_bus.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/drivers/mmc/core/sdio_bus.c b/drivers/mmc/core/sdio_bus.c index 3637483..2716c7a 100644 --- a/drivers/mmc/core/sdio_bus.c +++ b/drivers/mmc/core/sdio_bus.c @@ -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) -- 2.7.4