Initial import

1 files changed, 128 insertions, 0 deletions

diff --git a/drivers/cpuidle/cpuidle-ux500.c b/drivers/cpuidle/cpuidle-ux500.c
new file mode 100644
index 000000000..8bf895c00
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-ux500.c
@@ -0,0 +1,128 @@
+/*
+ * 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>
+
+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_TIMER_STOP,
+			.name		  = "ApIdle",
+			.desc		  = "ARM Retention",
+		},
+	},
+	.safe_state_index = 0,
+	.state_count = 2,
+};
+
+static int 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",
+	},
+	.probe = dbx500_cpuidle_probe,
+};
+
+module_platform_driver(dbx500_cpuidle_plat_driver);