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Commit 5670c2a5 authored by Krzysztof Kozlowski's avatar Krzysztof Kozlowski Committed by Russell King
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ARM: 8201/1: amba: Don't unprepare the clocks if device driver wants IRQ safe runtime PM v12 



The AMBA bus driver defines runtime Power Management functions which
disable and unprepare AMBA bus clock. This is problematic for runtime PM
because unpreparing a clock might sleep so it is not interrupt safe.

However some drivers may want to implement runtime PM functions in
interrupt-safe way (see pm_runtime_irq_safe()). In such case the AMBA
bus driver should only disable/enable the clock in runtime suspend and
resume callbacks.

Signed-off-by: default avatarKrzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent f560e322

drivers/amba/bus.c

+11 −4
Original line number Original line Diff line number Diff line
@@ -95,8 +95,12 @@ static int amba_pm_runtime_suspend(struct device *dev) 
	struct amba_device *pcdev = to_amba_device(dev);

	struct amba_device *pcdev = to_amba_device(dev);

	int ret = pm_generic_runtime_suspend(dev);

	int ret = pm_generic_runtime_suspend(dev);





	if (ret == 0 && dev->driver)

	if (ret == 0 && dev->driver) {

		if (pm_runtime_is_irq_safe(dev))

			clk_disable(pcdev->pclk);

		else

			clk_disable_unprepare(pcdev->pclk);

			clk_disable_unprepare(pcdev->pclk);

	}





	return ret;

	return ret;

}

}
@@ -107,6 +111,9 @@ static int amba_pm_runtime_resume(struct device *dev) 
	int ret;

	int ret;





	if (dev->driver) {

	if (dev->driver) {

		if (pm_runtime_is_irq_safe(dev))

			ret = clk_enable(pcdev->pclk);

		else

			ret = clk_prepare_enable(pcdev->pclk);

			ret = clk_prepare_enable(pcdev->pclk);

		/* Failure is probably fatal to the system, but... */

		/* Failure is probably fatal to the system, but... */

		if (ret)

		if (ret)
@@ -115,7 +122,7 @@ static int amba_pm_runtime_resume(struct device *dev) 




	return pm_generic_runtime_resume(dev);

	return pm_generic_runtime_resume(dev);

}

}

#endif

#endif /* CONFIG_PM */





static const struct dev_pm_ops amba_pm = {

static const struct dev_pm_ops amba_pm = {

	.suspend	= pm_generic_suspend,

	.suspend	= pm_generic_suspend,