ARM: PMU: fix runtime PM enable

Jon Hunter · wildea01 · commit 2ac29a14a8b6 · 2012-11-09T11:37:26.000Z
Commit 7be2958 (ARM: PMU: Add runtime PM Support) updated the ARM PMU code to use runtime PM which was prototyped and validated on the OMAP devices. In this commit, there is no call pm_runtime_enable() and for OMAP devices pm_runtime_enable() is currently being called from the OMAP PMU code when the PMU device is created. However, there are two problems with this: 1. For any other ARM device wishing to use runtime PM for PMU they will need to call pm_runtime_enable() for runtime PM to work. 2. When booting with device-tree and using device-tree to create the PMU device, pm_runtime_enable() needs to be called from within the ARM PERF driver as we are no longer calling any device specific code to create the device. Hence, PMU does not work on OMAP devices that use the runtime PM callbacks when using device-tree to create the PMU device. Therefore, call pm_runtime_enable() directly from the ARM PMU driver when registering the device. For platforms that do not use runtime PM, pm_runtime_enable() does nothing and for platforms that do use runtime PM but may not require it specifically for PMU, this will just add a little overhead when initialising and uninitialising the PMU device. Tested with PERF on OMAP2420, OMAP3430 and OMAP4460. Acked-by: Kevin Hilman <khilman@ti.com> Acked-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Jon Hunter <jon-hunter@ti.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
@@ -514,6 +514,7 @@ static void __init armpmu_init(struct arm_pmu *armpmu)
 int armpmu_register(struct arm_pmu *armpmu, int type)
 {
 	armpmu_init(armpmu);
+	pm_runtime_enable(&armpmu->plat_device->dev);
 	pr_info("enabled with %s PMU driver, %d counters available\n",
 			armpmu->name, armpmu->num_events);
 	return perf_pmu_register(&armpmu->pmu, armpmu->name, type);
diff --git a/arch/arm/mach-omap2/pmu.c b/arch/arm/mach-omap2/pmu.c
@@ -57,8 +57,6 @@ static int __init omap2_init_pmu(unsigned oh_num, char *oh_names[])
 	if (IS_ERR(omap_pmu_dev))
 		return PTR_ERR(omap_pmu_dev);
 
-	pm_runtime_enable(&omap_pmu_dev->dev);
-
 	return 0;
 }
 

Original file line number	Diff line number	Diff line change
`@@ -514,6 +514,7 @@ static void __init armpmu_init(struct arm_pmu *armpmu)`
`514`	`514`	`int armpmu_register(struct arm_pmu *armpmu, int type)`
`515`	`515`	`{`
`516`	`516`	`armpmu_init(armpmu);`
	`517`	`+ pm_runtime_enable(&armpmu->plat_device->dev);`
`517`	`518`	`pr_info("enabled with %s PMU driver, %d counters available\n",`
`518`	`519`	`armpmu->name, armpmu->num_events);`
`519`	`520`	`return perf_pmu_register(&armpmu->pmu, armpmu->name, type);`
Original file line number	Diff line number	Diff line change
`@@ -57,8 +57,6 @@ static int __init omap2_init_pmu(unsigned oh_num, char *oh_names[])`
`57`	`57`	`if (IS_ERR(omap_pmu_dev))`
`58`	`58`	`return PTR_ERR(omap_pmu_dev);`
`59`	`59`
`60`		`- pm_runtime_enable(&omap_pmu_dev->dev);`
`61`		`-`
`62`	`60`	`return 0;`
`63`	`61`	`}`
`64`	`62`