Merge branch 'linux-linaro-lsk' into linux-linaro-lsk-android

6 files changed, 474 insertions, 0 deletions

diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
index c4cc27e5c8a5..842d7ba83101 100644
--- a/drivers/cpuidle/Kconfig
+++ b/drivers/cpuidle/Kconfig
@@ -31,6 +31,15 @@ config CPU_IDLE_GOV_MENU
 config ARCH_NEEDS_CPU_IDLE_COUPLED
 	def_bool n
 
+config OF_IDLE_STATES
+        bool "Idle states DT support"
+	depends on ARM || ARM64
+	default n
+	help
+	 Allows the CPU idle framework to initialize CPU idle drivers
+	 state data by using DT provided nodes compliant with idle states
+	 device tree bindings.
+
 if CPU_IDLE
 
 config CPU_IDLE_CALXEDA
@@ -39,4 +48,9 @@ config CPU_IDLE_CALXEDA
 	help
 	  Select this to enable cpuidle on Calxeda processors.
 
+menu "ARM64 CPU Idle Drivers"
+depends on ARM64
+source "drivers/cpuidle/Kconfig.arm64"
+endmenu
+
 endif
diff --git a/drivers/cpuidle/Kconfig.arm64 b/drivers/cpuidle/Kconfig.arm64
new file mode 100644
index 000000000000..b83612c67e6d
--- /dev/null
+++ b/drivers/cpuidle/Kconfig.arm64
@@ -0,0 +1,13 @@
+#
+# ARM64 CPU Idle drivers
+#
+
+config ARM64_CPUIDLE
+	bool "Generic ARM64 CPU idle Driver"
+	select OF_IDLE_STATES
+	help
+	  Select this to enable generic cpuidle driver for ARM v8.
+	  It provides a generic idle driver whose idle states are configured
+	  at run-time through DT nodes. The CPUidle suspend backend is
+	  initialized by the device tree parsing code on matching the entry
+	  method to the respective CPU operations.
diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile
index 7d8256a5ea97..2d97bcfecd00 100644
--- a/drivers/cpuidle/Makefile
+++ b/drivers/cpuidle/Makefile
@@ -5,5 +5,11 @@
 obj-y += cpuidle.o driver.o governor.o sysfs.o governors/
 obj-$(CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED) += coupled.o
 obj-$(CONFIG_BIG_LITTLE) += arm_big_little.o
+obj-$(CONFIG_OF_IDLE_STATES)		  += of_idle_states.o
+
 obj-$(CONFIG_CPU_IDLE_CALXEDA) += cpuidle-calxeda.o
 obj-$(CONFIG_ARCH_KIRKWOOD) += cpuidle-kirkwood.o
+
+###############################################################################
+# ARM64 drivers
+obj-$(CONFIG_ARM64_CPUIDLE)		+= cpuidle-arm64.o
diff --git a/drivers/cpuidle/cpuidle-arm64.c b/drivers/cpuidle/cpuidle-arm64.c
new file mode 100644
index 000000000000..2cfde6ce3086
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-arm64.c
@@ -0,0 +1,159 @@
+/*
+ * 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.
+ */
+
+#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/psci.h>
+#include <asm/suspend.h>
+
+#include "of_idle_states.h"
+
+typedef int (*suspend_init_fn)(struct cpuidle_driver *,
+			       struct device_node *[]);
+
+struct cpu_suspend_ops {
+	const char *id;
+	suspend_init_fn init_fn;
+};
+
+static const struct cpu_suspend_ops suspend_operations[] __initconst = {
+	{"arm,psci", psci_dt_register_idle_states},
+	{}
+};
+
+static __init const struct cpu_suspend_ops *get_suspend_ops(const char *str)
+{
+	int i;
+
+	if (!str)
+		return NULL;
+
+	for (i = 0; suspend_operations[i].id; i++)
+		if (!strcmp(suspend_operations[i].id, str))
+			return &suspend_operations[i];
+
+	return NULL;
+}
+
+/*
+ * arm_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 arm_enter_idle_state(struct cpuidle_device *dev,
+				struct cpuidle_driver *drv, int idx)
+{
+	int ret;
+
+	if (!idx) {
+		cpu_do_idle();
+		return idx;
+	}
+
+	cpu_pm_enter();
+	/*
+	 * Pass idle state index to cpu_suspend which in turn will call
+	 * the CPU ops suspend protocol with idle index as a parameter.
+	 *
+	 * Some states would not require context to be saved and flushed
+	 * to DRAM, so calling cpu_suspend would not be stricly necessary.
+	 * When power domains specifications for ARM CPUs are finalized then
+	 * this code can be optimized to prevent saving registers if not
+	 * needed.
+	 */
+	ret = cpu_suspend(idx);
+
+	cpu_pm_exit();
+
+	return ret ? -1 : idx;
+}
+
+struct cpuidle_driver arm64_idle_driver = {
+	.name = "arm64_idle",
+	.owner = THIS_MODULE,
+};
+
+static struct device_node *state_nodes[CPUIDLE_STATE_MAX] __initdata;
+
+/*
+ * 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 i, ret;
+	const char *entry_method;
+	struct device_node *idle_states_node;
+	const struct cpu_suspend_ops *suspend_init;
+	struct cpuidle_driver *drv = &arm64_idle_driver;
+
+	idle_states_node = of_find_node_by_path("/cpus/idle-states");
+	if (!idle_states_node)
+		return -ENOENT;
+
+	if (of_property_read_string(idle_states_node, "entry-method",
+				    &entry_method)) {
+		pr_warn(" * %s missing entry-method property\n",
+			    idle_states_node->full_name);
+		of_node_put(idle_states_node);
+		return -EOPNOTSUPP;
+	}
+
+	suspend_init = get_suspend_ops(entry_method);
+	if (!suspend_init) {
+		pr_warn("Missing suspend initializer\n");
+		of_node_put(idle_states_node);
+		return -EOPNOTSUPP;
+	}
+
+	/*
+	 * 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.
+	 */
+	drv->states[0].exit_latency = 1;
+	drv->states[0].target_residency = 1;
+	drv->states[0].flags = CPUIDLE_FLAG_TIME_VALID;
+	strncpy(drv->states[0].name, "ARM WFI", CPUIDLE_NAME_LEN);
+	strncpy(drv->states[0].desc, "ARM WFI", CPUIDLE_DESC_LEN);
+
+	drv->cpumask = (struct cpumask *) cpu_possible_mask;
+	/*
+	 * Start at index 1, request idle state nodes to be filled
+	 */
+	ret = of_init_idle_driver(drv, state_nodes, 1, true);
+	if (ret)
+		return ret;
+
+	if (suspend_init->init_fn(drv, state_nodes))
+		return -EOPNOTSUPP;
+
+	for (i = 0; i < drv->state_count; i++)
+		drv->states[i].enter = arm_enter_idle_state;
+
+	return cpuidle_register(drv, NULL);
+}
+device_initcall(arm64_idle_init);
diff --git a/drivers/cpuidle/of_idle_states.c b/drivers/cpuidle/of_idle_states.c
new file mode 100644
index 000000000000..eceb1b4c4657
--- /dev/null
+++ b/drivers/cpuidle/of_idle_states.c
@@ -0,0 +1,274 @@
+/*
+ * OF idle states parsing code.
+ *
+ * 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.
+ */
+
+#include <linux/cpuidle.h>
+#include <linux/cpumask.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/list_sort.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+
+#include "of_idle_states.h"
+
+struct state_elem {
+	struct list_head list;
+	struct device_node *node;
+	int val;
+};
+
+static struct list_head head __initdata = LIST_HEAD_INIT(head);
+
+static bool __init state_cpu_valid(struct device_node *state_node,
+				   struct device_node *cpu_node)
+{
+	int i = 0;
+	struct device_node *cpu_state;
+
+	while ((cpu_state = of_parse_phandle(cpu_node,
+					     "cpu-idle-states", i++))) {
+		if (cpu_state && state_node == cpu_state) {
+			of_node_put(cpu_state);
+			return true;
+		}
+		of_node_put(cpu_state);
+	}
+	return false;
+}
+
+static bool __init state_cpus_valid(const cpumask_t *cpus,
+				    struct device_node *state_node)
+{
+	int cpu;
+	struct device_node *cpu_node;
+
+	/*
+	 * Check if state is valid on driver cpumask cpus
+	 */
+	for_each_cpu(cpu, cpus) {
+		cpu_node = of_get_cpu_node(cpu, NULL);
+
+		if (!cpu_node) {
+			pr_err("Missing device node for CPU %d\n", cpu);
+			return false;
+		}
+
+		if (!state_cpu_valid(state_node, cpu_node))
+			return false;
+	}
+
+	return true;
+}
+
+static int __init state_cmp(void *priv, struct list_head *a,
+			    struct list_head *b)
+{
+	struct state_elem *ela, *elb;
+
+	ela = container_of(a, struct state_elem, list);
+	elb = container_of(b, struct state_elem, list);
+
+	return ela->val - elb->val;
+}
+
+static int __init add_state_node(cpumask_t *cpumask,
+				 struct device_node *state_node)
+{
+	struct state_elem *el;
+	u32 val;
+
+	pr_debug(" * %s...\n", state_node->full_name);
+
+	if (!state_cpus_valid(cpumask, state_node))
+		return -EINVAL;
+	/*
+	 * Parse just the value required to sort the states.
+	 */
+	if (of_property_read_u32(state_node, "min-residency-us",
+				 &val)) {
+		pr_debug(" * %s missing min-residency-us property\n",
+			 state_node->full_name);
+		return -EINVAL;
+	}
+
+	el = kmalloc(sizeof(*el), GFP_KERNEL);
+	if (!el) {
+		pr_err("%s failed to allocate memory\n", __func__);
+		return -ENOMEM;
+	}
+
+	el->node = state_node;
+	el->val = val;
+	list_add_tail(&el->list, &head);
+
+	return 0;
+}
+
+static void __init init_state_node(struct cpuidle_driver *drv,
+				   struct device_node *state_node,
+				   int *cnt)
+{
+	struct cpuidle_state *idle_state;
+
+	pr_debug(" * %s...\n", state_node->full_name);
+
+	idle_state = &drv->states[*cnt];
+
+	if (of_property_read_u32(state_node, "exit-latency-us",
+				 &idle_state->exit_latency)) {
+		pr_debug(" * %s missing exit-latency-us property\n",
+			     state_node->full_name);
+		return;
+	}
+
+	if (of_property_read_u32(state_node, "min-residency-us",
+				 &idle_state->target_residency)) {
+		pr_debug(" * %s missing min-residency-us property\n",
+			     state_node->full_name);
+		return;
+	}
+	/*
+	 * It is unknown to the idle driver if and when the tick_device
+	 * loses context when the CPU enters the idle states. To solve
+	 * this issue the tick device must be linked to a power domain
+	 * so that the idle driver can check on which states the device
+	 * loses its context. Current code takes the conservative choice
+	 * of defining the idle state as one where the tick device always
+	 * loses its context. On platforms where tick device never loses
+	 * its context (ie it is not a C3STOP device) this turns into
+	 * a nop. On platforms where the tick device does lose context in some
+	 * states, this code can be optimized, when power domain specifications
+	 * for ARM CPUs are finalized.
+	 */
+	idle_state->flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TIMER_STOP;
+
+	strncpy(idle_state->name, state_node->name, CPUIDLE_NAME_LEN);
+	strncpy(idle_state->desc, state_node->name, CPUIDLE_NAME_LEN);
+
+	(*cnt)++;
+}
+
+static int __init init_idle_states(struct cpuidle_driver *drv,
+				   struct device_node *state_nodes[],
+				   unsigned int start_idx, bool init_nodes)
+{
+	struct state_elem *el;
+	struct list_head *curr, *tmp;
+	unsigned int cnt = start_idx;
+
+	list_for_each_entry(el, &head, list) {
+		/*
+		 * Check if the init function has to fill the
+		 * state_nodes array on behalf of the CPUidle driver.
+		 */
+		if (init_nodes)
+			state_nodes[cnt] = el->node;
+		/*
+		 * cnt is updated on return if a state was added.
+		 */
+		init_state_node(drv, el->node, &cnt);
+
+		if (cnt == CPUIDLE_STATE_MAX) {
+			pr_warn("State index reached static CPU idle state limit\n");
+			break;
+		}
+	}
+
+	drv->state_count = cnt;
+
+	list_for_each_safe(curr, tmp, &head) {
+		list_del(curr);
+		kfree(container_of(curr, struct state_elem, list));
+	}
+
+	/*
+	 * If no idle states are detected, return an error and let the idle
+	 * driver initialization fail accordingly.
+	 */
+	return (cnt > start_idx) ? 0 : -ENODATA;
+}
+
+static void __init add_idle_states(struct cpuidle_driver *drv,
+				   struct device_node *idle_states)
+{
+	struct device_node *state_node;
+
+	for_each_child_of_node(idle_states, state_node) {
+		if ((!of_device_is_compatible(state_node, "arm,idle-state"))) {
+			pr_warn(" * %s: children of /cpus/idle-states must be \"arm,idle-state\" compatible\n",
+				     state_node->full_name);
+			continue;
+		}
+		/*
+		 * If memory allocation fails, better bail out.
+		 * Initialized nodes are freed at initialization
+		 * completion in of_init_idle_driver().
+		 */
+		if ((add_state_node(drv->cpumask, state_node) == -ENOMEM))
+			break;
+	}
+	/*
+	 * Sort the states list before initializing the CPUidle driver
+	 * states array.
+	 */
+	list_sort(NULL, &head, state_cmp);
+}
+
+/*
+ * of_init_idle_driver - Parse the DT idle states and initialize the
+ *			 idle driver states array
+ *
+ * @drv:	  Pointer to CPU idle driver to be initialized
+ * @state_nodes:  Array of struct device_nodes to be initialized if
+ *		  init_nodes == true. Must be sized CPUIDLE_STATE_MAX
+ * @start_idx:    First idle state index to be initialized
+ * @init_nodes:   Boolean to request device nodes initialization
+ *
+ * Returns:
+ *	0 on success
+ *	<0 on failure
+ *
+ *	On success the states array in the cpuidle driver contains
+ *	initialized entries in the states array, starting from index start_idx.
+ *	If init_nodes == true, on success the state_nodes array is initialized
+ *	with idle state DT node pointers, starting from index start_idx,
+ *	in a 1:1 relation with the idle driver states array.
+ */
+int __init of_init_idle_driver(struct cpuidle_driver *drv,
+			       struct device_node *state_nodes[],
+			       unsigned int start_idx, bool init_nodes)
+{
+	struct device_node *idle_states_node;
+	int ret;
+
+	if (start_idx >= CPUIDLE_STATE_MAX) {
+		pr_warn("State index exceeds static CPU idle driver states array size\n");
+		return -EINVAL;
+	}
+
+	if (WARN(init_nodes && !state_nodes,
+		"Requested nodes stashing in an invalid nodes container\n"))
+		return -EINVAL;
+
+	idle_states_node = of_find_node_by_path("/cpus/idle-states");
+	if (!idle_states_node)
+		return -ENOENT;
+
+	add_idle_states(drv, idle_states_node);
+
+	ret = init_idle_states(drv, state_nodes, start_idx, init_nodes);
+
+	of_node_put(idle_states_node);
+
+	return ret;
+}
diff --git a/drivers/cpuidle/of_idle_states.h b/drivers/cpuidle/of_idle_states.h
new file mode 100644
index 000000000000..049f94ff4428
--- /dev/null
+++ b/drivers/cpuidle/of_idle_states.h
@@ -0,0 +1,8 @@
+#ifndef __OF_IDLE_STATES
+#define __OF_IDLE_STATES
+
+int __init of_init_idle_driver(struct cpuidle_driver *drv,
+			       struct device_node *state_nodes[],
+			       unsigned int start_idx,
+			       bool init_nodes);
+#endif