| Message ID | 1415802748-30530-4-git-send-email-k.kozlowski@samsung.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On 12 November 2014 15:32, Krzysztof Kozlowski <k.kozlowski@samsung.com> wrote: > 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: Krzysztof Kozlowski <k.kozlowski@samsung.com> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> > --- > drivers/amba/bus.c | 15 +++++++++++---- > 1 file changed, 11 insertions(+), 4 deletions(-) > > diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c > index a4ac490dd784..c2153a1d1981 100644 > --- a/drivers/amba/bus.c > +++ b/drivers/amba/bus.c > @@ -95,8 +95,12 @@ static int amba_pm_runtime_suspend(struct device *dev) > struct amba_device *pcdev = to_amba_device(dev); > int ret = pm_generic_runtime_suspend(dev); > > - if (ret == 0 && dev->driver) > - clk_disable_unprepare(pcdev->pclk); > + if (ret == 0 && dev->driver) { > + if (pm_runtime_is_irq_safe(dev)) > + clk_disable(pcdev->pclk); > + else > + clk_disable_unprepare(pcdev->pclk); > + } > > return ret; > } > @@ -107,7 +111,10 @@ static int amba_pm_runtime_resume(struct device *dev) > int ret; > > if (dev->driver) { > - ret = clk_prepare_enable(pcdev->pclk); > + if (pm_runtime_is_irq_safe(dev)) > + ret = clk_enable(pcdev->pclk); > + else > + ret = clk_prepare_enable(pcdev->pclk); > /* Failure is probably fatal to the system, but... */ > if (ret) > return ret; > @@ -115,7 +122,7 @@ static int amba_pm_runtime_resume(struct device *dev) > > return pm_generic_runtime_resume(dev); > } > -#endif > +#endif /* CONFIG_PM */ > > static const struct dev_pm_ops amba_pm = { > .suspend = pm_generic_suspend, > -- > 1.9.1 > -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c index a4ac490dd784..c2153a1d1981 100644 --- a/drivers/amba/bus.c +++ b/drivers/amba/bus.c @@ -95,8 +95,12 @@ static int amba_pm_runtime_suspend(struct device *dev) struct amba_device *pcdev = to_amba_device(dev); int ret = pm_generic_runtime_suspend(dev); - if (ret == 0 && dev->driver) - clk_disable_unprepare(pcdev->pclk); + if (ret == 0 && dev->driver) { + if (pm_runtime_is_irq_safe(dev)) + clk_disable(pcdev->pclk); + else + clk_disable_unprepare(pcdev->pclk); + } return ret; } @@ -107,7 +111,10 @@ static int amba_pm_runtime_resume(struct device *dev) int ret; if (dev->driver) { - ret = clk_prepare_enable(pcdev->pclk); + if (pm_runtime_is_irq_safe(dev)) + ret = clk_enable(pcdev->pclk); + else + ret = clk_prepare_enable(pcdev->pclk); /* Failure is probably fatal to the system, but... */ if (ret) return ret; @@ -115,7 +122,7 @@ static int amba_pm_runtime_resume(struct device *dev) return pm_generic_runtime_resume(dev); } -#endif +#endif /* CONFIG_PM */ static const struct dev_pm_ops amba_pm = { .suspend = pm_generic_suspend,
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: Krzysztof Kozlowski <k.kozlowski@samsung.com> --- drivers/amba/bus.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-)