OMAP4: cpuidle: Basic CPUidle support

The patch adds a basic CPUidle driver for OMAP4. Just
one C state is registered for CPU0 which does a WFI.
CPU1 is left with defualt idle and the low power state
for it is managed via cpu-hotplug.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Kevin Hilman <khilman@ti.com>

1 files changed, 161 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/cpuidle44xx.c b/arch/arm/mach-omap2/cpuidle44xx.c
new file mode 100644
index 0000000..270404f
--- /dev/null
+++ b/arch/arm/mach-omap2/cpuidle44xx.c
@@ -0,0 +1,161 @@
+/*
+ * OMAP4 CPU idle Routines
+ *
+ * Copyright (C) 2011 Texas Instruments, Inc.
+ * Rajendra Nayak <rnayak@ti.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/sched.h>
+#include <linux/cpuidle.h>
+
+#include <asm/proc-fns.h>
+
+#include <mach/omap4-common.h>
+
+#include "pm.h"
+
+#ifdef CONFIG_CPU_IDLE
+
+#define OMAP4_MAX_STATES	1
+/* C1 - CPU0 ON + + CPU1 ON + MPU ON + CORE ON */
+#define OMAP4_STATE_C1		0
+
+struct omap4_processor_cx {
+	u8 valid;
+	u8 type;
+	u32 sleep_latency;
+	u32 wakeup_latency;
+	u32 cpu0_state;
+	u32 mpu_state;
+	u32 core_state;
+	u32 threshold;
+	u32 flags;
+};
+
+struct omap4_processor_cx omap4_power_states[OMAP4_MAX_STATES];
+
+static struct cpuidle_params cpuidle_params_table[] = {
+	/* C1 */
+	{1, 2, 2, 5},
+};
+
+/**
+ * omap4_enter_idle - Programs OMAP4 to enter the specified state
+ * @dev: cpuidle device
+ * @state: The target state to be programmed
+ *
+ * Called from the CPUidle framework to program the device to the
+ * specified low power state selected by the governor.
+ * Returns the amount of time spent in the low power state.
+ */
+static int omap4_enter_idle(struct cpuidle_device *dev,
+			struct cpuidle_state *state)
+{
+	struct timespec ts_preidle, ts_postidle, ts_idle;
+
+	/* Used to keep track of the total time in idle */
+	getnstimeofday(&ts_preidle);
+
+	local_irq_disable();
+	local_fiq_disable();
+
+	cpu_do_idle();
+
+	getnstimeofday(&ts_postidle);
+	ts_idle = timespec_sub(ts_postidle, ts_preidle);
+
+	local_irq_enable();
+	local_fiq_enable();
+
+	return ts_idle.tv_nsec / NSEC_PER_USEC + ts_idle.tv_sec * USEC_PER_SEC;
+}
+
+DEFINE_PER_CPU(struct cpuidle_device, omap4_idle_dev);
+
+/**
+ * omap4_init_power_states - Initialises the OMAP4 specific C states.
+ *
+ * Below is the desciption of each C state.
+ * C1 : CPUx wfi + MPU inative + Core inactive
+ */
+void omap4_init_power_states(void)
+{
+	/*
+	 * C1 - CPU0 ON + + CPU1 ON + MPU ON + CORE ON
+	 */
+	omap4_power_states[OMAP4_STATE_C1].valid =
+			cpuidle_params_table[OMAP4_STATE_C1].valid;
+	omap4_power_states[OMAP4_STATE_C1].type = OMAP4_STATE_C1;
+	omap4_power_states[OMAP4_STATE_C1].sleep_latency =
+			cpuidle_params_table[OMAP4_STATE_C1].sleep_latency;
+	omap4_power_states[OMAP4_STATE_C1].wakeup_latency =
+			cpuidle_params_table[OMAP4_STATE_C1].wake_latency;
+	omap4_power_states[OMAP4_STATE_C1].threshold =
+			cpuidle_params_table[OMAP4_STATE_C1].threshold;
+	omap4_power_states[OMAP4_STATE_C1].mpu_state = PWRDM_POWER_ON;
+	omap4_power_states[OMAP4_STATE_C1].core_state = PWRDM_POWER_ON;
+	omap4_power_states[OMAP4_STATE_C1].flags = CPUIDLE_FLAG_TIME_VALID;
+
+}
+
+struct cpuidle_driver omap4_idle_driver = {
+	.name =		"omap4_idle",
+	.owner =	THIS_MODULE,
+};
+
+/**
+ * omap4_idle_init - Init routine for OMAP4 idle
+ *
+ * Registers the OMAP4 specific cpuidle driver with the cpuidle
+ * framework with the valid set of states.
+ */
+int __init omap4_idle_init(void)
+{
+	int cpu_id = 0, i, count = 0;
+	struct omap4_processor_cx *cx;
+	struct cpuidle_state *state;
+	struct cpuidle_device *dev;
+
+	omap4_init_power_states();
+	cpuidle_register_driver(&omap4_idle_driver);
+
+	dev = &per_cpu(omap4_idle_dev, cpu_id);
+	dev->cpu = cpu_id;
+	count = 0;
+	for (i = OMAP4_STATE_C1; i < OMAP4_MAX_STATES; i++) {
+		cx = &omap4_power_states[i];
+		state = &dev->states[count];
+
+		if (!cx->valid)
+			continue;
+		cpuidle_set_statedata(state, cx);
+		state->exit_latency = cx->sleep_latency +
+						cx->wakeup_latency;
+		state->target_residency = cx->threshold;
+		state->flags = cx->flags;
+		state->enter = omap4_enter_idle;
+		sprintf(state->name, "C%d", count+1);
+		count++;
+	}
+
+	if (!count)
+		return -EINVAL;
+	dev->state_count = count;
+
+	if (cpuidle_register_device(dev)) {
+		pr_err("%s: CPUidle register device failed\n", __func__);
+			return -EIO;
+		}
+
+	return 0;
+}
+#else
+int __init omap4_idle_init(void)
+{
+	return 0;
+}
+#endif /* CONFIG_CPU_IDLE */