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-rw-r--r--arch/arm/common/bL_switcher.c60
-rw-r--r--arch/arm/include/asm/bL_switcher.h44
2 files changed, 94 insertions, 10 deletions
diff --git a/arch/arm/common/bL_switcher.c b/arch/arm/common/bL_switcher.c
index bda51ca23eb..ec0d94dde46 100644
--- a/arch/arm/common/bL_switcher.c
+++ b/arch/arm/common/bL_switcher.c
@@ -22,6 +22,7 @@
#include <linux/clockchips.h>
#include <linux/hrtimer.h>
#include <linux/tick.h>
+#include <linux/notifier.h>
#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/string.h>
@@ -347,10 +348,34 @@ EXPORT_SYMBOL_GPL(bL_switch_request);
*/
static DEFINE_MUTEX(bL_switcher_activation_lock);
+static BLOCKING_NOTIFIER_HEAD(bL_activation_notifier);
static unsigned int bL_switcher_active;
static unsigned int bL_switcher_cpu_original_cluster[NR_CPUS];
static cpumask_t bL_switcher_removed_logical_cpus;
+int bL_switcher_register_notifier(struct notifier_block *nb)
+{
+ return blocking_notifier_chain_register(&bL_activation_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(bL_switcher_register_notifier);
+
+int bL_switcher_unregister_notifier(struct notifier_block *nb)
+{
+ return blocking_notifier_chain_unregister(&bL_activation_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(bL_switcher_unregister_notifier);
+
+static int bL_activation_notify(unsigned long val)
+{
+ int ret;
+
+ ret = blocking_notifier_call_chain(&bL_activation_notifier, val, NULL);
+ if (ret & NOTIFY_STOP_MASK)
+ pr_err("%s: notifier chain failed with status 0x%x\n",
+ __func__, ret);
+ return notifier_to_errno(ret);
+}
+
static void bL_switcher_restore_cpus(void)
{
int i;
@@ -468,12 +493,13 @@ static int bL_switcher_enable(void)
pr_info("big.LITTLE switcher initializing\n");
+ ret = bL_activation_notify(BL_NOTIFY_PRE_ENABLE);
+ if (ret)
+ goto error;
+
ret = bL_switcher_halve_cpus();
- if (ret) {
- cpu_hotplug_driver_unlock();
- mutex_unlock(&bL_switcher_activation_lock);
- return ret;
- }
+ if (ret)
+ goto error;
for_each_online_cpu(cpu) {
struct bL_thread *t = &bL_threads[cpu];
@@ -484,11 +510,18 @@ static int bL_switcher_enable(void)
}
bL_switcher_active = 1;
+ bL_activation_notify(BL_NOTIFY_POST_ENABLE);
pr_info("big.LITTLE switcher initialized\n");
+ goto out;
+error:
+ pr_warning("big.LITTLE switcher initialization failed\n");
+ bL_activation_notify(BL_NOTIFY_POST_DISABLE);
+
+out:
cpu_hotplug_driver_unlock();
mutex_unlock(&bL_switcher_activation_lock);
- return 0;
+ return ret;
}
#ifdef CONFIG_SYSFS
@@ -501,11 +534,15 @@ static void bL_switcher_disable(void)
mutex_lock(&bL_switcher_activation_lock);
cpu_hotplug_driver_lock();
- if (!bL_switcher_active) {
- cpu_hotplug_driver_unlock();
- mutex_unlock(&bL_switcher_activation_lock);
- return;
+
+ if (!bL_switcher_active)
+ goto out;
+
+ if (bL_activation_notify(BL_NOTIFY_PRE_DISABLE) != 0) {
+ bL_activation_notify(BL_NOTIFY_POST_ENABLE);
+ goto out;
}
+
bL_switcher_active = 0;
/*
@@ -547,6 +584,9 @@ static void bL_switcher_disable(void)
}
bL_switcher_restore_cpus();
+ bL_activation_notify(BL_NOTIFY_POST_DISABLE);
+
+out:
cpu_hotplug_driver_unlock();
mutex_unlock(&bL_switcher_activation_lock);
}
diff --git a/arch/arm/include/asm/bL_switcher.h b/arch/arm/include/asm/bL_switcher.h
index bc23d1c8bea..914739d17e3 100644
--- a/arch/arm/include/asm/bL_switcher.h
+++ b/arch/arm/include/asm/bL_switcher.h
@@ -12,9 +12,53 @@
#ifndef ASM_BL_SWITCHER_H
#define ASM_BL_SWITCHER_H
+#include <linux/compiler.h>
+#include <linux/types.h>
+
int bL_switch_request(unsigned int cpu, unsigned int new_cluster_id);
+/*
+ * Register here to be notified about runtime enabling/disabling of
+ * the switcher.
+ *
+ * The notifier chain is called with the switcher activation lock held:
+ * the switcher will not be enabled or disabled during callbacks.
+ * Callbacks must not call bL_switcher_{get,put}_enabled().
+ */
+#define BL_NOTIFY_PRE_ENABLE 0
+#define BL_NOTIFY_POST_ENABLE 1
+#define BL_NOTIFY_PRE_DISABLE 2
+#define BL_NOTIFY_POST_DISABLE 3
+
+#ifdef CONFIG_BL_SWITCHER
+
+int bL_switcher_register_notifier(struct notifier_block *nb);
+int bL_switcher_unregister_notifier(struct notifier_block *nb);
+
+/*
+ * Use these functions to temporarily prevent enabling/disabling of
+ * the switcher.
+ * bL_switcher_get_enabled() returns true if the switcher is currently
+ * enabled. Each call to bL_switcher_get_enabled() must be followed
+ * by a call to bL_switcher_put_enabled(). These functions are not
+ * recursive.
+ */
bool bL_switcher_get_enabled(void);
void bL_switcher_put_enabled(void);
+#else
+static inline int bL_switcher_register_notifier(struct notifier_block *nb)
+{
+ return 0;
+}
+
+static inline int bL_switcher_unregister_notifier(struct notifier_block *nb)
+{
+ return 0;
+}
+
+static inline bool bL_switcher_get_enabled(void) { return false; }
+static inline void bL_switcher_put_enabled(void) { }
+#endif /* CONFIG_BL_SWITCHER */
+
#endif