Merge branch 'ux500-cpuidle-for-arm-soc' of...

Merge branch 'ux500-cpuidle-for-arm-soc' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-stericsson into next/cpuidle

From: Linus Walleij <linus.walleij@linaro.org>

* 'ux500-cpuidle-for-arm-soc' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-stericsson:
  ARM: ux500: add the cpuidle driver for WFI and ARM retention
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/mach-ux500/Makefile

@@ -4,6 +4,7 @@
 
 obj-y				:= clock.o cpu.o devices.o devices-common.o \
 				   id.o usb.o timer.o
+obj-$(CONFIG_CPU_IDLE)          += cpuidle.o
 obj-$(CONFIG_CACHE_L2X0)	+= cache-l2x0.o
 obj-$(CONFIG_UX500_SOC_DB5500)	+= cpu-db5500.o dma-db5500.o
 obj-$(CONFIG_UX500_SOC_DB8500)	+= cpu-db8500.o devices-db8500.o

arch/arm/mach-ux500/cpuidle.c

+/*
+ * 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);