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-rw-r--r--arch/arm/mach-ux500/cpuidle.c171
1 files changed, 171 insertions, 0 deletions
diff --git a/arch/arm/mach-ux500/cpuidle.c b/arch/arm/mach-ux500/cpuidle.c
new file mode 100644
index 0000000..b54884bd
--- /dev/null
+++ b/arch/arm/mach-ux500/cpuidle.c
@@ -0,0 +1,171 @@
+/*
+ * Copyright (c) 2012 Linaro : Daniel Lezcano <daniel.lezcano@linaro.org> (IBM)
+ *
+ * Based on the work of Rickard Andersson <rickard.andersson@stericsson.com>
+ * and Jonas Aaberg <jonas.aberg@stericsson.com>.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/cpuidle.h>
+#include <linux/clockchips.h>
+#include <linux/spinlock.h>
+#include <linux/atomic.h>
+#include <linux/smp.h>
+#include <linux/mfd/dbx500-prcmu.h>
+
+#include <asm/cpuidle.h>
+#include <asm/proc-fns.h>
+
+static atomic_t master = ATOMIC_INIT(0);
+static DEFINE_SPINLOCK(master_lock);
+static DEFINE_PER_CPU(struct cpuidle_device, ux500_cpuidle_device);
+
+static inline int ux500_enter_idle(struct cpuidle_device *dev,
+ struct cpuidle_driver *drv, int index)
+{
+ int this_cpu = smp_processor_id();
+ bool recouple = false;
+
+ clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &this_cpu);
+
+ if (atomic_inc_return(&master) == num_online_cpus()) {
+
+ /* With this lock, we prevent the other cpu to exit and enter
+ * this function again and become the master */
+ if (!spin_trylock(&master_lock))
+ goto wfi;
+
+ /* decouple the gic from the A9 cores */
+ if (prcmu_gic_decouple())
+ goto out;
+
+ /* If an error occur, we will have to recouple the gic
+ * manually */
+ recouple = true;
+
+ /* At this state, as the gic is decoupled, if the other
+ * cpu is in WFI, we have the guarantee it won't be wake
+ * up, so we can safely go to retention */
+ if (!prcmu_is_cpu_in_wfi(this_cpu ? 0 : 1))
+ goto out;
+
+ /* The prcmu will be in charge of watching the interrupts
+ * and wake up the cpus */
+ if (prcmu_copy_gic_settings())
+ goto out;
+
+ /* Check in the meantime an interrupt did
+ * not occur on the gic ... */
+ if (prcmu_gic_pending_irq())
+ goto out;
+
+ /* ... and the prcmu */
+ if (prcmu_pending_irq())
+ goto out;
+
+ /* Go to the retention state, the prcmu will wait for the
+ * cpu to go WFI and this is what happens after exiting this
+ * 'master' critical section */
+ if (prcmu_set_power_state(PRCMU_AP_IDLE, true, true))
+ goto out;
+
+ /* When we switch to retention, the prcmu is in charge
+ * of recoupling the gic automatically */
+ recouple = false;
+
+ spin_unlock(&master_lock);
+ }
+wfi:
+ cpu_do_idle();
+out:
+ atomic_dec(&master);
+
+ if (recouple) {
+ prcmu_gic_recouple();
+ spin_unlock(&master_lock);
+ }
+
+ clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &this_cpu);
+
+ return index;
+}
+
+static struct cpuidle_driver ux500_idle_driver = {
+ .name = "ux500_idle",
+ .owner = THIS_MODULE,
+ .en_core_tk_irqen = 1,
+ .states = {
+ ARM_CPUIDLE_WFI_STATE,
+ {
+ .enter = ux500_enter_idle,
+ .exit_latency = 70,
+ .target_residency = 260,
+ .flags = CPUIDLE_FLAG_TIME_VALID,
+ .name = "ApIdle",
+ .desc = "ARM Retention",
+ },
+ },
+ .safe_state_index = 0,
+ .state_count = 2,
+};
+
+/*
+ * For each cpu, setup the broadcast timer because we will
+ * need to migrate the timers for the states >= ApIdle.
+ */
+static void ux500_setup_broadcast_timer(void *arg)
+{
+ int cpu = smp_processor_id();
+ clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ON, &cpu);
+}
+
+int __init ux500_idle_init(void)
+{
+ int ret, cpu;
+ struct cpuidle_device *device;
+
+ /* Configure wake up reasons */
+ prcmu_enable_wakeups(PRCMU_WAKEUP(ARM) | PRCMU_WAKEUP(RTC) |
+ PRCMU_WAKEUP(ABB));
+
+ /*
+ * Configure the timer broadcast for each cpu, that must
+ * be done from the cpu context, so we use a smp cross
+ * call with 'on_each_cpu'.
+ */
+ on_each_cpu(ux500_setup_broadcast_timer, NULL, 1);
+
+ ret = cpuidle_register_driver(&ux500_idle_driver);
+ if (ret) {
+ printk(KERN_ERR "failed to register ux500 idle driver\n");
+ return ret;
+ }
+
+ for_each_online_cpu(cpu) {
+ device = &per_cpu(ux500_cpuidle_device, cpu);
+ device->cpu = cpu;
+ ret = cpuidle_register_device(device);
+ if (ret) {
+ printk(KERN_ERR "Failed to register cpuidle "
+ "device for cpu%d\n", cpu);
+ goto out_unregister;
+ }
+ }
+out:
+ return ret;
+
+out_unregister:
+ for_each_online_cpu(cpu) {
+ device = &per_cpu(ux500_cpuidle_device, cpu);
+ cpuidle_unregister_device(device);
+ }
+
+ cpuidle_unregister_driver(&ux500_idle_driver);
+ goto out;
+}
+
+device_initcall(ux500_idle_init);