1 files changed, 133 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle-arm64.c b/drivers/cpuidle/cpuidle-arm64.c
new file mode 100644
index 000000000000..50997ea942fc
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-arm64.c
@@ -0,0 +1,133 @@
+/*
+ * ARM64 generic CPU idle driver.
+ *
+ * Copyright (C) 2014 ARM Ltd.
+ * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.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.
+ */
+
+#define pr_fmt(fmt) "CPUidle arm64: " fmt
+
+#include <linux/cpuidle.h>
+#include <linux/cpumask.h>
+#include <linux/cpu_pm.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+
+#include <asm/cpuidle.h>
+#include <asm/suspend.h>
+
+#include "dt_idle_states.h"
+
+/*
+ * arm64_enter_idle_state - Programs CPU to enter the specified state
+ *
+ * dev: cpuidle device
+ * drv: cpuidle driver
+ * idx: state index
+ *
+ * Called from the CPUidle framework to program the device to the
+ * specified target state selected by the governor.
+ */
+static int arm64_enter_idle_state(struct cpuidle_device *dev,
+				  struct cpuidle_driver *drv, int idx)
+{
+	int ret;
+
+	if (!idx) {
+		cpu_do_idle();
+		return idx;
+	}
+
+	ret = cpu_pm_enter();
+	if (!ret) {
+		/*
+		 * Pass idle state index to cpu_suspend which in turn will
+		 * call the CPU ops suspend protocol with idle index as a
+		 * parameter.
+		 */
+		ret = cpu_suspend(idx);
+
+		cpu_pm_exit();
+	}
+
+	return ret ? -1 : idx;
+}
+
+static struct cpuidle_driver arm64_idle_driver = {
+	.name = "arm64_idle",
+	.owner = THIS_MODULE,
+	/*
+	 * State at index 0 is standby wfi and considered standard
+	 * on all ARM platforms. If in some platforms simple wfi
+	 * can't be used as "state 0", DT bindings must be implemented
+	 * to work around this issue and allow installing a special
+	 * handler for idle state index 0.
+	 */
+	.states[0] = {
+		.enter                  = arm64_enter_idle_state,
+		.exit_latency           = 1,
+		.target_residency       = 1,
+		.power_usage		= UINT_MAX,
+		.flags                  = CPUIDLE_FLAG_TIME_VALID,
+		.name                   = "WFI",
+		.desc                   = "ARM64 WFI",
+	}
+};
+
+static const struct of_device_id arm64_idle_state_match[] __initconst = {
+	{ .compatible = "arm,idle-state",
+	  .data = arm64_enter_idle_state },
+	{ },
+};
+
+/*
+ * arm64_idle_init
+ *
+ * Registers the arm64 specific cpuidle driver with the cpuidle
+ * framework. It relies on core code to parse the idle states
+ * and initialize them using driver data structures accordingly.
+ */
+static int __init arm64_idle_init(void)
+{
+	int cpu, ret;
+	struct cpuidle_driver *drv = &arm64_idle_driver;
+
+	/*
+	 * Initialize idle states data, starting at index 1.
+	 * This driver is DT only, if no DT idle states are detected (ret == 0)
+	 * let the driver initialization fail accordingly since there is no
+	 * reason to initialize the idle driver if only wfi is supported.
+	 */
+	ret = dt_init_idle_driver(drv, arm64_idle_state_match, 1);
+	if (ret <= 0) {
+		if (ret)
+			pr_err("failed to initialize idle states\n");
+		return ret ? : -ENODEV;
+	}
+
+	/*
+	 * Call arch CPU operations in order to initialize
+	 * idle states suspend back-end specific data
+	 */
+	for_each_possible_cpu(cpu) {
+		ret = cpu_init_idle(cpu);
+		if (ret) {
+			pr_err("CPU %d failed to init idle CPU ops\n", cpu);
+			return ret;
+		}
+	}
+
+	ret = cpuidle_register(drv, NULL);
+	if (ret) {
+		pr_err("failed to register cpuidle driver\n");
+		return ret;
+	}
+
+	return 0;
+}
+device_initcall(arm64_idle_init);