Merge branch 'next/cpuidle' into next/pm

No point maintaining two branches for power management

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

2 files changed, 172 insertions, 0 deletions

diff --git a/arch/arm/mach-ux500/Makefile b/arch/arm/mach-ux500/Makefile
index 465b9ec9510a..93a191afba7a 100644
--- a/arch/arm/mach-ux500/Makefile
+++ b/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
diff --git a/arch/arm/mach-ux500/cpuidle.c b/arch/arm/mach-ux500/cpuidle.c
new file mode 100644
index 000000000000..b54884bd2549
--- /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);