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path: root/drivers/cpuidle/cpuidle-ux500.c
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Diffstat (limited to 'drivers/cpuidle/cpuidle-ux500.c')
-rw-r--r--drivers/cpuidle/cpuidle-ux500.c131
1 files changed, 131 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle-ux500.c b/drivers/cpuidle/cpuidle-ux500.c
new file mode 100644
index 0000000..e056465
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-ux500.c
@@ -0,0 +1,131 @@
+/*
+ * 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/spinlock.h>
+#include <linux/atomic.h>
+#include <linux/smp.h>
+#include <linux/mfd/dbx500-prcmu.h>
+#include <linux/platform_data/arm-ux500-pm.h>
+#include <linux/platform_device.h>
+
+#include <asm/cpuidle.h>
+#include <asm/proc-fns.h>
+
+static atomic_t master = ATOMIC_INIT(0);
+static DEFINE_SPINLOCK(master_lock);
+
+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;
+
+ 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()) {
+ spin_unlock(&master_lock);
+ 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);
+ }
+
+ return index;
+}
+
+static struct cpuidle_driver ux500_idle_driver = {
+ .name = "ux500_idle",
+ .owner = THIS_MODULE,
+ .states = {
+ ARM_CPUIDLE_WFI_STATE,
+ {
+ .enter = ux500_enter_idle,
+ .exit_latency = 70,
+ .target_residency = 260,
+ .flags = CPUIDLE_FLAG_TIME_VALID |
+ CPUIDLE_FLAG_TIMER_STOP,
+ .name = "ApIdle",
+ .desc = "ARM Retention",
+ },
+ },
+ .safe_state_index = 0,
+ .state_count = 2,
+};
+
+static int __init dbx500_cpuidle_probe(struct platform_device *pdev)
+{
+ /* Configure wake up reasons */
+ prcmu_enable_wakeups(PRCMU_WAKEUP(ARM) | PRCMU_WAKEUP(RTC) |
+ PRCMU_WAKEUP(ABB));
+
+ return cpuidle_register(&ux500_idle_driver, NULL);
+}
+
+static struct platform_driver dbx500_cpuidle_plat_driver = {
+ .driver = {
+ .name = "cpuidle-dbx500",
+ .owner = THIS_MODULE,
+ },
+ .probe = dbx500_cpuidle_probe,
+};
+
+module_platform_driver(dbx500_cpuidle_plat_driver);