cpufreq: cpufreq_stats: Register for bL_switcher notifiers

cpufreq_stat has registered notifiers with both cpufreq and cpu core. It adds
cpu/cpu0/cpufreq/stats/ directory with a notifier of cpufreq CPUFREQ_NOTIFY and
removes this directory with a notifier to cpu core.

On bL_switcher enable/disable, cpufreq drivers notifiers gets called and they
call cpufreq_unregister(), followed by cpufreq_register(). For unregister stats
directories per cpu aren't removed, because cpu never went to dead state and cpu
notifier isn't called.

When cpufreq_register() is called, we try to add these directories again and
that simply fails, as directories were already present.

Fix these issues by registering cpufreq_stats too with bL_switcher notifiers, so
that they get unregistered and registered on switcher enable/disable.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

1 files changed, 47 insertions, 2 deletions

diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
index bfd6273fd87..1db214b2660 100644
--- a/drivers/cpufreq/cpufreq_stats.c
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -21,6 +21,7 @@
 #include <linux/spinlock.h>
 #include <linux/notifier.h>
 #include <asm/cputime.h>
+#include <asm/bL_switcher.h>
 
 static spinlock_t cpufreq_stats_lock;
 
@@ -378,7 +379,7 @@ static struct notifier_block notifier_trans_block = {
 	.notifier_call = cpufreq_stat_notifier_trans
 };
 
-static int __init cpufreq_stats_init(void)
+static int cpufreq_stats_setup(void)
 {
 	int ret;
 	unsigned int cpu;
@@ -406,7 +407,8 @@ static int __init cpufreq_stats_init(void)
 
 	return 0;
 }
-static void __exit cpufreq_stats_exit(void)
+
+static void cpufreq_stats_cleanup(void)
 {
 	unsigned int cpu;
 
@@ -421,6 +423,49 @@ static void __exit cpufreq_stats_exit(void)
 	}
 }
 
+static int cpufreq_stats_switcher_notifier(struct notifier_block *nfb,
+					unsigned long action, void *_arg)
+{
+	switch (action) {
+	case BL_NOTIFY_PRE_ENABLE:
+	case BL_NOTIFY_PRE_DISABLE:
+		cpufreq_stats_cleanup();
+		break;
+
+	case BL_NOTIFY_POST_ENABLE:
+	case BL_NOTIFY_POST_DISABLE:
+		cpufreq_stats_setup();
+		break;
+
+	default:
+		return NOTIFY_DONE;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block switcher_notifier = {
+	.notifier_call = cpufreq_stats_switcher_notifier,
+};
+
+static int __init cpufreq_stats_init(void)
+{
+	int ret;
+	spin_lock_init(&cpufreq_stats_lock);
+
+	ret = cpufreq_stats_setup();
+	if (!ret)
+		bL_switcher_register_notifier(&switcher_notifier);
+
+	return ret;
+}
+
+static void __exit cpufreq_stats_exit(void)
+{
+	bL_switcher_unregister_notifier(&switcher_notifier);
+	cpufreq_stats_cleanup();
+}
+
 MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
 MODULE_DESCRIPTION("'cpufreq_stats' - A driver to export cpufreq stats "
 				"through sysfs filesystem");