diff options
| -rw-r--r-- | arch/arm/common/bL_switcher.c | 60 | ||||
| -rw-r--r-- | arch/arm/include/asm/bL_switcher.h | 44 |
2 files changed, 94 insertions, 10 deletions
diff --git a/arch/arm/common/bL_switcher.c b/arch/arm/common/bL_switcher.c index c41d722ee6e..e55b55170be 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> @@ -343,10 +344,34 @@ 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[MAX_CPUS_PER_CLUSTER]; 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; @@ -430,12 +455,13 @@ 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]; @@ -446,11 +472,18 @@ 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 @@ -463,11 +496,15 @@ 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; /* @@ -514,6 +551,9 @@ 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 |