4 files changed, 156 insertions, 0 deletions

diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
index 8deb934c6356..c5029c1209b4 100644
--- a/drivers/cpuidle/Kconfig
+++ b/drivers/cpuidle/Kconfig
@@ -33,6 +33,11 @@ depends on ARM
 source "drivers/cpuidle/Kconfig.arm"
 endmenu
 
+menu "ARM64 CPU Idle Drivers"
+depends on ARM64
+source "drivers/cpuidle/Kconfig.arm64"
+endmenu
+
 menu "MIPS CPU Idle Drivers"
 depends on MIPS
 source "drivers/cpuidle/Kconfig.mips"
diff --git a/drivers/cpuidle/Kconfig.arm64 b/drivers/cpuidle/Kconfig.arm64
new file mode 100644
index 000000000000..d0a08ed1b2ee
--- /dev/null
+++ b/drivers/cpuidle/Kconfig.arm64
@@ -0,0 +1,14 @@
+#
+# ARM64 CPU Idle drivers
+#
+
+config ARM64_CPUIDLE
+        bool "Generic ARM64 CPU idle Driver"
+        select ARM64_CPU_SUSPEND
+        select DT_IDLE_STATES
+        help
+          Select this to enable generic cpuidle driver for ARM64.
+          It provides a generic idle driver whose idle states are configured
+          at run-time through DT nodes. The CPUidle suspend backend is
+          initialized by calling the CPU operations init idle hook
+          provided by architecture code.
diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile
index 002b65336ba9..4d177b916f75 100644
--- a/drivers/cpuidle/Makefile
+++ b/drivers/cpuidle/Makefile
@@ -23,6 +23,10 @@ obj-$(CONFIG_ARM_EXYNOS_CPUIDLE)        += cpuidle-exynos.o
 obj-$(CONFIG_MIPS_CPS_CPUIDLE)          += cpuidle-cps.o
 
 ###############################################################################
+# ARM64 drivers
+obj-$(CONFIG_ARM64_CPUIDLE)             += cpuidle-arm64.o
+
+###############################################################################
 # POWERPC drivers
 obj-$(CONFIG_PSERIES_CPUIDLE)           += cpuidle-pseries.o
 obj-$(CONFIG_POWERNV_CPUIDLE)           += cpuidle-powernv.o
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);