ARM: mach-shmobile: CPUIdle support
This patch adds a shared SH-Mobile ARM specific CPUIdle
implementation supporting WFI only at this point. It
serves as a common point for late registration of the
arch-specific CPUIdle code, and supports adding extra
sleep modes using the callback shmobile_cpuidle_setup()
together with shmobile_cpuidle_modes[].
Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/arm/mach-shmobile/cpuidle.c b/arch/arm/mach-shmobile/cpuidle.c
new file mode 100644
index 0000000..2e44f11
--- /dev/null
+++ b/arch/arm/mach-shmobile/cpuidle.c
@@ -0,0 +1,92 @@
+/*
+ * CPUIdle support code for SH-Mobile ARM
+ *
+ * Copyright (C) 2011 Magnus Damm
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/pm.h>
+#include <linux/cpuidle.h>
+#include <linux/suspend.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <asm/system.h>
+#include <asm/io.h>
+
+static void shmobile_enter_wfi(void)
+{
+ cpu_do_idle();
+}
+
+void (*shmobile_cpuidle_modes[CPUIDLE_STATE_MAX])(void) = {
+ shmobile_enter_wfi, /* regular sleep mode */
+};
+
+static int shmobile_cpuidle_enter(struct cpuidle_device *dev,
+ struct cpuidle_state *state)
+{
+ ktime_t before, after;
+ int requested_state = state - &dev->states[0];
+
+ dev->last_state = &dev->states[requested_state];
+ before = ktime_get();
+
+ local_irq_disable();
+ local_fiq_disable();
+
+ shmobile_cpuidle_modes[requested_state]();
+
+ local_irq_enable();
+ local_fiq_enable();
+
+ after = ktime_get();
+ return ktime_to_ns(ktime_sub(after, before)) >> 10;
+}
+
+static struct cpuidle_device shmobile_cpuidle_dev;
+static struct cpuidle_driver shmobile_cpuidle_driver = {
+ .name = "shmobile_cpuidle",
+ .owner = THIS_MODULE,
+};
+
+void (*shmobile_cpuidle_setup)(struct cpuidle_device *dev);
+
+static int shmobile_cpuidle_init(void)
+{
+ struct cpuidle_device *dev = &shmobile_cpuidle_dev;
+ struct cpuidle_state *state;
+ int i;
+
+ cpuidle_register_driver(&shmobile_cpuidle_driver);
+
+ for (i = 0; i < CPUIDLE_STATE_MAX; i++) {
+ dev->states[i].name[0] = '\0';
+ dev->states[i].desc[0] = '\0';
+ dev->states[i].enter = shmobile_cpuidle_enter;
+ }
+
+ i = CPUIDLE_DRIVER_STATE_START;
+
+ state = &dev->states[i++];
+ snprintf(state->name, CPUIDLE_NAME_LEN, "C1");
+ strncpy(state->desc, "WFI", CPUIDLE_DESC_LEN);
+ state->exit_latency = 1;
+ state->target_residency = 1 * 2;
+ state->power_usage = 3;
+ state->flags = 0;
+ state->flags |= CPUIDLE_FLAG_TIME_VALID;
+
+ dev->safe_state = state;
+ dev->state_count = i;
+
+ if (shmobile_cpuidle_setup)
+ shmobile_cpuidle_setup(dev);
+
+ cpuidle_register_device(dev);
+
+ return 0;
+}
+late_initcall(shmobile_cpuidle_init);