1 files changed, 26 insertions, 40 deletions

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 0f17ad8585d..b03771d4787 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -28,6 +28,7 @@
 #include <linux/cpu.h>
 #include <linux/completion.h>
 #include <linux/mutex.h>
+#include <linux/syscore_ops.h>
 
 #include <trace/events/power.h>
 
@@ -1340,35 +1341,31 @@ out:
 }
 EXPORT_SYMBOL(cpufreq_get);
 
+static struct sysdev_driver cpufreq_sysdev_driver = {
+	.add		= cpufreq_add_dev,
+	.remove		= cpufreq_remove_dev,
+};
+
 
 /**
- *	cpufreq_suspend - let the low level driver prepare for suspend
+ * cpufreq_bp_suspend - Prepare the boot CPU for system suspend.
+ *
+ * This function is only executed for the boot processor.  The other CPUs
+ * have been put offline by means of CPU hotplug.
  */
-
-static int cpufreq_suspend(struct sys_device *sysdev, pm_message_t pmsg)
+static int cpufreq_bp_suspend(void)
 {
 	int ret = 0;
 
-	int cpu = sysdev->id;
+	int cpu = smp_processor_id();
 	struct cpufreq_policy *cpu_policy;
 
 	dprintk("suspending cpu %u\n", cpu);
 
-	if (!cpu_online(cpu))
-		return 0;
-
-	/* we may be lax here as interrupts are off. Nonetheless
-	 * we need to grab the correct cpu policy, as to check
-	 * whether we really run on this CPU.
-	 */
-
+	/* If there's no policy for the boot CPU, we have nothing to do. */
 	cpu_policy = cpufreq_cpu_get(cpu);
 	if (!cpu_policy)
-		return -EINVAL;
-
-	/* only handle each CPU group once */
-	if (unlikely(cpu_policy->cpu != cpu))
-		goto out;
+		return 0;
 
 	if (cpufreq_driver->suspend) {
 		ret = cpufreq_driver->suspend(cpu_policy);
@@ -1377,13 +1374,12 @@ static int cpufreq_suspend(struct sys_device *sysdev, pm_message_t pmsg)
 					"step on CPU %u\n", cpu_policy->cpu);
 	}
 
-out:
 	cpufreq_cpu_put(cpu_policy);
 	return ret;
 }
 
 /**
- *	cpufreq_resume -  restore proper CPU frequency handling after resume
+ * cpufreq_bp_resume - Restore proper frequency handling of the boot CPU.
  *
  *	1.) resume CPUfreq hardware support (cpufreq_driver->resume())
  *	2.) schedule call cpufreq_update_policy() ASAP as interrupts are
@@ -1391,31 +1387,23 @@ out:
  *	    what we believe it to be. This is a bit later than when it
  *	    should be, but nonethteless it's better than calling
  *	    cpufreq_driver->get() here which might re-enable interrupts...
+ *
+ * This function is only executed for the boot CPU.  The other CPUs have not
+ * been turned on yet.
  */
-static int cpufreq_resume(struct sys_device *sysdev)
+static void cpufreq_bp_resume(void)
 {
 	int ret = 0;
 
-	int cpu = sysdev->id;
+	int cpu = smp_processor_id();
 	struct cpufreq_policy *cpu_policy;
 
 	dprintk("resuming cpu %u\n", cpu);
 
-	if (!cpu_online(cpu))
-		return 0;
-
-	/* we may be lax here as interrupts are off. Nonetheless
-	 * we need to grab the correct cpu policy, as to check
-	 * whether we really run on this CPU.
-	 */
-
+	/* If there's no policy for the boot CPU, we have nothing to do. */
 	cpu_policy = cpufreq_cpu_get(cpu);
 	if (!cpu_policy)
-		return -EINVAL;
-
-	/* only handle each CPU group once */
-	if (unlikely(cpu_policy->cpu != cpu))
-		goto fail;
+		return;
 
 	if (cpufreq_driver->resume) {
 		ret = cpufreq_driver->resume(cpu_policy);
@@ -1430,14 +1418,11 @@ static int cpufreq_resume(struct sys_device *sysdev)
 
 fail:
 	cpufreq_cpu_put(cpu_policy);
-	return ret;
 }
 
-static struct sysdev_driver cpufreq_sysdev_driver = {
-	.add		= cpufreq_add_dev,
-	.remove		= cpufreq_remove_dev,
-	.suspend	= cpufreq_suspend,
-	.resume		= cpufreq_resume,
+static struct syscore_ops cpufreq_syscore_ops = {
+	.suspend	= cpufreq_bp_suspend,
+	.resume		= cpufreq_bp_resume,
 };
 
 
@@ -2002,6 +1987,7 @@ static int __init cpufreq_core_init(void)
 	cpufreq_global_kobject = kobject_create_and_add("cpufreq",
 						&cpu_sysdev_class.kset.kobj);
 	BUG_ON(!cpufreq_global_kobject);
+	register_syscore_ops(&cpufreq_syscore_ops);
 
 	return 0;
 }