@@ -94,8 +94,18 @@ 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) {
+ /*
+ * Drivers should not change pm_runtime_is_irq_safe()
+ * after probe.
+ */
+ WARN_ON(pcdev->irq_safe != pm_runtime_is_irq_safe(dev));
+
+ if (pcdev->irq_safe)
+ clk_disable(pcdev->pclk);
+ else
+ clk_disable_unprepare(pcdev->pclk);
+ }
return ret;
}
@@ -106,7 +116,16 @@ static int amba_pm_runtime_resume(struct device *dev)
int ret;
if (dev->driver) {
- ret = clk_prepare_enable(pcdev->pclk);
+ /*
+ * Drivers should not change pm_runtime_is_irq_safe()
+ * after probe.
+ */
+ WARN_ON(pcdev->irq_safe != pm_runtime_is_irq_safe(dev));
+
+ if (pcdev->irq_safe)
+ ret = clk_enable(pcdev->pclk);
+ else
+ ret = clk_prepare_enable(pcdev->pclk);
/* Failure is probably fatal to the system, but... */
if (ret)
return ret;
@@ -191,8 +210,11 @@ static int amba_probe(struct device *dev)
pm_runtime_enable(dev);
ret = pcdrv->probe(pcdev, id);
- if (ret == 0)
+ if (ret == 0) {
+ if (pm_runtime_is_irq_safe(dev))
+ pcdev->irq_safe = 1;
break;
+ }
pm_runtime_disable(dev);
pm_runtime_set_suspended(dev);
@@ -32,6 +32,7 @@ struct amba_device {
struct clk *pclk;
unsigned int periphid;
unsigned int irq[AMBA_NR_IRQS];
+ unsigned int irq_safe:1;
};
struct amba_driver {
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 not unprepare/prepare the clock in runtime suspend and resume callbacks. Detect the device driver behavior after calling its probe function and store it. During runtime suspend/resume deal with clocks according to stored value. Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> --- drivers/amba/bus.c | 30 ++++++++++++++++++++++++++---- include/linux/amba/bus.h | 1 + 2 files changed, 27 insertions(+), 4 deletions(-)