1 files changed, 233 insertions, 0 deletions

diff --git a/kernel/cpu_pm.c b/kernel/cpu_pm.c
new file mode 100644
index 000000000000..249152e15308
--- /dev/null
+++ b/kernel/cpu_pm.c
@@ -0,0 +1,233 @@
+/*
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * Author:
+ *      Colin Cross <ccross@android.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/cpu_pm.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/spinlock.h>
+#include <linux/syscore_ops.h>
+
+static DEFINE_RWLOCK(cpu_pm_notifier_lock);
+static RAW_NOTIFIER_HEAD(cpu_pm_notifier_chain);
+
+static int cpu_pm_notify(enum cpu_pm_event event, int nr_to_call, int *nr_calls)
+{
+        int ret;
+
+        ret = __raw_notifier_call_chain(&cpu_pm_notifier_chain, event, NULL,
+                nr_to_call, nr_calls);
+
+        return notifier_to_errno(ret);
+}
+
+/**
+ * cpu_pm_register_notifier - register a driver with cpu_pm
+ * @nb: notifier block to register
+ *
+ * Add a driver to a list of drivers that are notified about
+ * CPU and CPU cluster low power entry and exit.
+ *
+ * This function may sleep, and has the same return conditions as
+ * raw_notifier_chain_register.
+ */
+int cpu_pm_register_notifier(struct notifier_block *nb)
+{
+        unsigned long flags;
+        int ret;
+
+        write_lock_irqsave(&cpu_pm_notifier_lock, flags);
+        ret = raw_notifier_chain_register(&cpu_pm_notifier_chain, nb);
+        write_unlock_irqrestore(&cpu_pm_notifier_lock, flags);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(cpu_pm_register_notifier);
+
+/**
+ * cpu_pm_unregister_notifier - unregister a driver with cpu_pm
+ * @nb: notifier block to be unregistered
+ *
+ * Remove a driver from the CPU PM notifier list.
+ *
+ * This function may sleep, and has the same return conditions as
+ * raw_notifier_chain_unregister.
+ */
+int cpu_pm_unregister_notifier(struct notifier_block *nb)
+{
+        unsigned long flags;
+        int ret;
+
+        write_lock_irqsave(&cpu_pm_notifier_lock, flags);
+        ret = raw_notifier_chain_unregister(&cpu_pm_notifier_chain, nb);
+        write_unlock_irqrestore(&cpu_pm_notifier_lock, flags);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier);
+
+/**
+ * cpm_pm_enter - CPU low power entry notifier
+ *
+ * Notifies listeners that a single CPU is entering a low power state that may
+ * cause some blocks in the same power domain as the cpu to reset.
+ *
+ * Must be called on the affected CPU with interrupts disabled.  Platform is
+ * responsible for ensuring that cpu_pm_enter is not called twice on the same
+ * CPU before cpu_pm_exit is called. Notified drivers can include VFP
+ * co-processor, interrupt controller and it's PM extensions, local CPU
+ * timers context save/restore which shouldn't be interrupted. Hence it
+ * must be called with interrupts disabled.
+ *
+ * Return conditions are same as __raw_notifier_call_chain.
+ */
+int cpu_pm_enter(void)
+{
+        int nr_calls;
+        int ret = 0;
+
+        read_lock(&cpu_pm_notifier_lock);
+        ret = cpu_pm_notify(CPU_PM_ENTER, -1, &nr_calls);
+        if (ret)
+                /*
+                 * Inform listeners (nr_calls - 1) about failure of CPU PM
+                 * PM entry who are notified earlier to prepare for it.
+                 */
+                cpu_pm_notify(CPU_PM_ENTER_FAILED, nr_calls - 1, NULL);
+        read_unlock(&cpu_pm_notifier_lock);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(cpu_pm_enter);
+
+/**
+ * cpm_pm_exit - CPU low power exit notifier
+ *
+ * Notifies listeners that a single CPU is exiting a low power state that may
+ * have caused some blocks in the same power domain as the cpu to reset.
+ *
+ * Notified drivers can include VFP co-processor, interrupt controller
+ * and it's PM extensions, local CPU timers context save/restore which
+ * shouldn't be interrupted. Hence it must be called with interrupts disabled.
+ *
+ * Return conditions are same as __raw_notifier_call_chain.
+ */
+int cpu_pm_exit(void)
+{
+        int ret;
+
+        read_lock(&cpu_pm_notifier_lock);
+        ret = cpu_pm_notify(CPU_PM_EXIT, -1, NULL);
+        read_unlock(&cpu_pm_notifier_lock);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(cpu_pm_exit);
+
+/**
+ * cpm_cluster_pm_enter - CPU cluster low power entry notifier
+ *
+ * Notifies listeners that all cpus in a power domain are entering a low power
+ * state that may cause some blocks in the same power domain to reset.
+ *
+ * Must be called after cpu_pm_enter has been called on all cpus in the power
+ * domain, and before cpu_pm_exit has been called on any cpu in the power
+ * domain. Notified drivers can include VFP co-processor, interrupt controller
+ * and it's PM extensions, local CPU timers context save/restore which
+ * shouldn't be interrupted. Hence it must be called with interrupts disabled.
+ *
+ * Must be called with interrupts disabled.
+ *
+ * Return conditions are same as __raw_notifier_call_chain.
+ */
+int cpu_cluster_pm_enter(void)
+{
+        int nr_calls;
+        int ret = 0;
+
+        read_lock(&cpu_pm_notifier_lock);
+        ret = cpu_pm_notify(CPU_CLUSTER_PM_ENTER, -1, &nr_calls);
+        if (ret)
+                /*
+                 * Inform listeners (nr_calls - 1) about failure of CPU cluster
+                 * PM entry who are notified earlier to prepare for it.
+                 */
+                cpu_pm_notify(CPU_CLUSTER_PM_ENTER_FAILED, nr_calls - 1, NULL);
+        read_unlock(&cpu_pm_notifier_lock);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter);
+
+/**
+ * cpm_cluster_pm_exit - CPU cluster low power exit notifier
+ *
+ * Notifies listeners that all cpus in a power domain are exiting form a
+ * low power state that may have caused some blocks in the same power domain
+ * to reset.
+ *
+ * Must be called after cpu_pm_exit has been called on all cpus in the power
+ * domain, and before cpu_pm_exit has been called on any cpu in the power
+ * domain. Notified drivers can include VFP co-processor, interrupt controller
+ * and it's PM extensions, local CPU timers context save/restore which
+ * shouldn't be interrupted. Hence it must be called with interrupts disabled.
+ *
+ * Return conditions are same as __raw_notifier_call_chain.
+ */
+int cpu_cluster_pm_exit(void)
+{
+        int ret;
+
+        read_lock(&cpu_pm_notifier_lock);
+        ret = cpu_pm_notify(CPU_CLUSTER_PM_EXIT, -1, NULL);
+        read_unlock(&cpu_pm_notifier_lock);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit);
+
+#ifdef CONFIG_PM
+static int cpu_pm_suspend(void)
+{
+        int ret;
+
+        ret = cpu_pm_enter();
+        if (ret)
+                return ret;
+
+        ret = cpu_cluster_pm_enter();
+        return ret;
+}
+
+static void cpu_pm_resume(void)
+{
+        cpu_cluster_pm_exit();
+        cpu_pm_exit();
+}
+
+static struct syscore_ops cpu_pm_syscore_ops = {
+        .suspend = cpu_pm_suspend,
+        .resume = cpu_pm_resume,
+};
+
+static int cpu_pm_init(void)
+{
+        register_syscore_ops(&cpu_pm_syscore_ops);
+        return 0;
+}
+core_initcall(cpu_pm_init);
+#endif