---
drivers/Makefile | 1 +
drivers/cpuoffline/Kconfig | 26 ++
drivers/cpuoffline/Makefile | 2 +
drivers/cpuoffline/cpuoffline.c | 488 +++++++++++++++++++++++++++++++++++++++
include/linux/cpuoffline.h | 82 +++++++
5 files changed, 599 insertions(+), 0 deletions(-)
create mode 100644 drivers/cpuoffline/Kconfig
create mode 100644 drivers/cpuoffline/Makefile
create mode 100644 drivers/cpuoffline/cpuoffline.c
create mode 100644 include/linux/cpuoffline.h
diff --git a/drivers/Makefile b/drivers/Makefile
index dde8076..d41e183 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -95,6 +95,7 @@ obj-$(CONFIG_EISA) += eisa/
obj-y += lguest/
obj-$(CONFIG_CPU_FREQ) += cpufreq/
obj-$(CONFIG_CPU_IDLE) += cpuidle/
+obj-$(CONFIG_CPU_OFFLINE) += cpuoffline/
obj-$(CONFIG_MMC) += mmc/
obj-$(CONFIG_MEMSTICK) += memstick/
obj-y += leds/
diff --git a/drivers/cpuoffline/Kconfig b/drivers/cpuoffline/Kconfig
new file mode 100644
index 0000000..57057d4
--- /dev/null
+++ b/drivers/cpuoffline/Kconfig
@@ -0,0 +1,26 @@
+config CPU_OFFLINE
+ bool "CPUoffline framework"
+ help
+ CPUoffline provides a framework that allows for taking CPUs
+ offline via an in-kernel governor. The governor itself can
+ implement any number of policies for deciding to offline a
+ core. Though primarily used for power capping, CPUoffline can
+ also be used to implement a thermal duty to prevent core
+ over-heating, etc.
+
+ For details please see <file:Documentation/cpuoffline>.
+
+ If in doubt, say N.
+
+config CPU_OFFLINE_DEFAULT_DRIVER
+ bool "CPUoffline default driver"
+ depends on CPU_OFFLINE
+ help
+ A default driver that creates a single partition containing
+ all possible CPUs. The benefit of this driver is that a
+ platform does not need any new code to make use of the
+ CPUoffline framework. Do not select this if your platform
+ implements it's own driver for registering partitions and CPUs
+ with the CPUoffline framework.
+
+ If in doubt, say N.
diff --git a/drivers/cpuoffline/Makefile b/drivers/cpuoffline/Makefile
new file mode 100644
index 0000000..0b5aa59
--- /dev/null
+++ b/drivers/cpuoffline/Makefile
@@ -0,0 +1,2 @@
+# CPUoffline core
+obj-$(CONFIG_CPU_OFFLINE) += cpuoffline.o
diff --git a/drivers/cpuoffline/cpuoffline.c b/drivers/cpuoffline/cpuoffline.c
new file mode 100644
index 0000000..0427df3
--- /dev/null
+++ b/drivers/cpuoffline/cpuoffline.c
@@ -0,0 +1,488 @@
+/*
+ * CPU Offline framework core
+ *
+ * Copyright (C) 2011 Texas Instruments, Inc.
+ * Mike Turquette <mturque...@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/mutex.h>
+#include <linux/cpuoffline.h>
+#include <linux/slab.h>
+//#include <linux/kobject.h>
+#include <linux/sysfs.h>
+#include <linux/err.h>
+
+#define MAX_CPU_LEN 8
+
+static int nr_partitions = 0;
+
+static struct cpuoffline_driver *cpuoffline_driver;
+DEFINE_MUTEX(cpuoffline_driver_mutex);
+
+static LIST_HEAD(cpuoffline_governor_list);
+static DEFINE_MUTEX(cpuoffline_governor_mutex);
+
+static DEFINE_PER_CPU(struct cpuoffline_partition *, cpuoffline_partition);
+
+struct kobject *cpuoffline_global_kobject;
+EXPORT_SYMBOL(cpuoffline_global_kobject);
+
+/* sysfs interfaces */
+
+static struct cpuoffline_governor *__find_governor(const char *str_governor)
+{
+ struct cpuoffline_governor *gov;
+
+ list_for_each_entry(gov, &cpuoffline_governor_list, governor_list)
+ if (!strnicmp(str_governor, gov->name, MAX_NAME_LEN))
+ return gov;
+
+ return NULL;
+}
+
+static ssize_t current_governor_show(struct cpuoffline_partition *partition,
+ char *buf)
+{
+ struct cpuoffline_governor *gov;
+
+ gov = partition->governor;
+
+ if (!gov)
+ return 0;
+
+ return snprintf(buf, MAX_NAME_LEN, "%s\n", gov->name);
+}
+
+static ssize_t current_governor_store(struct cpuoffline_partition *partition,
+ const char *buf, size_t count)
+{
+ int ret;
+ char govstring[MAX_NAME_LEN];
+ struct cpuoffline_governor *gov, *tempgov;
+
+ gov = partition->governor;
+
+ ret = sscanf(buf, "%15s", govstring);
+
+ if (ret != 1)
+ return -EINVAL;
+
+ tempgov = __find_governor(govstring);
+
+ if (!tempgov)
+ return -EINVAL;
+
+ if (!try_module_get(tempgov->owner))
+ return -EINVAL;
+
+ /* XXX should gov->stop handle the module put? probably not */
+ if (gov) {
+ gov->stop(partition);
+ module_put(gov->owner);
+ }
+
+ /* XXX kfree the governor? is this a memleak? */
+ partition->governor = gov = tempgov;
+
+ gov->start(partition);
+
+ return count;
+}
+
+static ssize_t available_governors_show(struct cpuoffline_partition *partition,
+ char *buf)
+{
+ ssize_t ret = 0;
+ struct cpuoffline_governor *gov;
+
+ list_for_each_entry(gov, &cpuoffline_governor_list, governor_list)
+ ret += snprintf(buf, MAX_NAME_LEN, "%s\n", gov->name);
+
+ return ret;
+}
+
+static ssize_t partition_show(struct kobject *kobj, struct attribute *attr,
+ char *buf)
+{
+ struct cpuoffline_partition *partition;
+ struct cpuoffline_attribute *c_attr;
+ ssize_t ret;
+
+ partition = container_of(kobj, struct cpuoffline_partition, kobj);
+ c_attr = container_of(attr, struct cpuoffline_attribute, attr);
+
+ if (!partition || !c_attr)
+ return -EINVAL;
+
+ mutex_lock(&partition->mutex);
+ /* refcount++ */
+ kobject_get(&partition->kobj);
+
+ if (c_attr->show)
+ ret = c_attr->show(partition, buf);
+ else
+ ret = -EIO;
+
+ /* refcount-- */
+ kobject_put(&partition->kobj);
+
+ mutex_unlock(&partition->mutex);
+ return ret;
+}
+
+static ssize_t partition_store(struct kobject *kobj, struct attribute *attr,
+ const char *buf, size_t count)
+{
+ struct cpuoffline_partition *partition;
+ struct cpuoffline_attribute *c_attr;
+ ssize_t ret = -EINVAL;
+
+ partition = container_of(kobj, struct cpuoffline_partition, kobj);
+ c_attr = container_of(attr, struct cpuoffline_attribute, attr);
+
+ if (!partition || !c_attr)
+ goto out;
+
+ mutex_lock(&partition->mutex);
+ /* refcount++ */
+ kobject_get(&partition->kobj);
+
+ if(c_attr->store)
+ ret = c_attr->store(partition, buf, count);
+ else
+ ret = -EIO;
+
+ /* refcount-- */
+ kobject_put(&partition->kobj);
+
+out:
+ mutex_unlock(&partition->mutex);
+ return ret;
+}
+
+
+static struct cpuoffline_attribute current_governor =
+ __ATTR(current_governor, (S_IRUGO | S_IWUSR), current_governor_show,
+ current_governor_store);
+
+static struct cpuoffline_attribute available_governors =
+ __ATTR_RO(available_governors);
+
+static struct attribute *partition_default_attrs[] = {
+ ¤t_governor.attr,
+ &available_governors.attr,
+ NULL,
+};
+
+static const struct sysfs_ops partition_ops = {
+ .show = partition_show,
+ .store = partition_store,
+};
+
+static void cpuoffline_partition_release(struct kobject *kobj)
+{
+ struct cpuoffline_partition *partition;
+
+ partition = container_of(kobj, struct cpuoffline_partition, kobj);
+
+ complete(&partition->kobj_unregister);
+}
+
+static struct kobj_type partition_ktype = {
+ .sysfs_ops = &partition_ops,
+ .default_attrs = partition_default_attrs,
+ .release = cpuoffline_partition_release,
+};
+
+/* cpu class sysdev device registration */
+
+static int cpuoffline_add_dev_interface(struct cpuoffline_partition *partition,
+ struct sys_device *sys_dev)
+{
+ int ret = 0;
+ char name[MAX_CPU_LEN];
+ struct kobject *kobj;
+
+ /* create cpuoffline directory for this CPU */
+ /*ret = kobject_init_and_add(&kobj, &ktype_device,
+ &sys_dev->kobj, "%s", "cpuoffline");*/
+ kobj = kobject_create_and_add("cpuoffline", &sys_dev->kobj);
+
+ if (!kobj) {
+ pr_warning("%s: failed to create cpuoffline dir for cpu %d\n",
+ __func__, sys_dev->id);
+ return -ENOMEM;
+ }
+
+#ifdef CONFIG_CPU_OFFLINE_STATISTICS
+ /* XXX set up per-CPU statistics here, which is ktype_device */
+ /* create directory for cpuoffline stats */
+#endif
+
+ /* create a symlink from this cpu to its partition */
+ ret = sysfs_create_link(kobj, &partition->kobj, "partition");
+
+ if (ret)
+ pr_warning("%s: failed to create symlink from cpu %d to
partition %d\n",
+ __func__, sys_dev->id, partition->id);
+
+ /* create a symlink from this cpu's partition to itself */
+ snprintf(name, MAX_CPU_LEN, "cpu%d", sys_dev->id);
+ ret = sysfs_create_link(&partition->kobj, kobj, name);
+
+ if (ret)
+ pr_warning("%s: failed to create symlink from partition %d to
cpu %d\n",
+ __func__, partition->id, sys_dev->id);
+
+ return 0;
+}
+
+static int cpuoffline_add_partition_interface(
+ struct cpuoffline_partition *partition)
+{
+ return kobject_init_and_add(&partition->kobj, &partition_ktype,
+ cpuoffline_global_kobject, "%s%d", "partition",
+ partition->id);
+}
+
+struct cpuoffline_partition *cpuoffline_partition_init(unsigned int cpu)
+{
+ int ret = -ENOMEM;
+ struct cpuoffline_partition *partition;
+
+ partition = kzalloc(sizeof(struct cpuoffline_partition),
+ GFP_KERNEL);
+ if (!partition)
+ goto out;
+
+ if (!zalloc_cpumask_var(&partition->cpus, GFP_KERNEL))
+ goto err_free_partition;
+
+ /* start populating ->cpus with this cpu first */
+ cpumask_copy(partition->cpus, cpumask_of(cpu));
+
+ mutex_init(&partition->mutex);
+
+ /* helps sysfs look pretty */
+ partition->id = nr_partitions++;
+
+ ret = cpuoffline_driver->init(partition);
+
+ if (ret) {
+ pr_err("%s: failed to init driver\n", __func__);
+ goto err_free_cpus;
+ }
+
+ /* create directory in sysfs for this partition */
+ ret = cpuoffline_add_partition_interface(partition);
+
+ /* decrement partition->kobj if the above returns error */
+ if (ret) {
+ pr_warn("%s: failed to create partition interface\n", __func__);
+ kobject_put(&partition->kobj);
+ }
+
+ return partition;
+
+err_free_cpus:
+ nr_partitions--;
+ free_cpumask_var(partition->cpus);
+err_free_partition:
+ kfree(partition);
+out:
+ return (void *)ret;
+}
+
+/* does not need locking because sequence is synchronous and orderly */
+static int cpuoffline_add_dev(struct sys_device *sys_dev)
+{
+ unsigned int cpu = sys_dev->id;
+ int ret = 0;
+ struct cpuoffline_partition *partition;
+
+ /* sanity checks */
+ if (cpu_is_offline(cpu))
+ pr_notice("%s: CPU%d is offline\n", __func__, cpu);
+
+ if (!cpuoffline_driver)
+ return -EINVAL;
+
+ partition = per_cpu(cpuoffline_partition, cpu);
+
+ /*
+ * The first cpu in each partition to hit this function will allocate
+ * partition and populate partition's address into the per-cpu data for
+ * each of the CPUs in the same. It is up to the driver->init function
+ * to do this since only the CPUoffline platform driver knows the
+ * desired topology.
+ *
+ * When the other CPUs in a partition hit this path, their partition
+ * wll have already been allocated. Only thing left to do is set up
+ * sysfs entries.
+ */
+ if (!partition) {
+ partition = cpuoffline_partition_init(cpu);
+
+ if (IS_ERR(partition)) {
+ pr_warn("%s: failed to create partition\n", __func__);
+ return -ENOMEM;
+ }
+ }
+
+ ret = cpuoffline_add_dev_interface(partition, sys_dev);
+
+ return ret;
+}
+
+static int cpuoffline_remove_dev(struct sys_device *sys_dev)
+{
+ pr_err("%s: GETTING REMOVED!\n", __func__);
+ return 0;
+}
+
+static struct sysdev_driver cpuoffline_sysdev_driver = {
+ .add = cpuoffline_add_dev,
+ .remove = cpuoffline_remove_dev,
+};
+
+/* driver registration API */
+
+int cpuoffline_register_driver(struct cpuoffline_driver *driver)
+{
+ int ret = 0;
+
+ pr_info("CPUoffline: registering %s driver", driver->name);
+
+ if (!driver)
+ return -EINVAL;
+
+ mutex_lock(&cpuoffline_driver_mutex);
+
+ /* there can only be one */
+ if (cpuoffline_driver)
+ ret = -EBUSY;
+ else
+ cpuoffline_driver = driver;
+
+ mutex_unlock(&cpuoffline_driver_mutex);
+
+ if (ret)
+ goto out;
+
+ /* register every CPUoffline device */
+ ret = sysdev_driver_register(&cpu_sysdev_class,
+ &cpuoffline_sysdev_driver);
+
+out:
+ return ret;
+}
+EXPORT_SYMBOL_GPL(cpuoffline_register_driver);
+
+/* FIXME - should this be allowed? */
+int cpuoffline_unregister_driver(struct cpuoffline_driver *driver)
+{
+ pr_info("CPUoffline: unregistering %s driver\n", driver->name);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(cpuoffline_unregister_driver);
+
+/* default driver - single partition containing all CPUs */
+
+#ifdef CONFIG_CPU_OFFLINE_DEFAULT_DRIVER
+/**
+ * cpuoffline_default_driver_init - create a single partition with all CPUs
+ * @partition: CPUoffline partition that is yet to be populated
+ *
+ * A CPUoffline driver's init function is responsible for two pieces of data.
+ * First, for every CPU that should be in @partition, the driver init function
+ * must populate a per-cpu pointer to that partition. Second, for every CPU
+ * that should be in @partition, the driver init function must set that bit in
+ * the @partition->cpus cpumask.
+ */
+int cpuoffline_default_driver_init(struct cpuoffline_partition *partition)
+{
+ unsigned int cpu;
+
+ /* sanity checks */
+ if (!partition)
+ return -EINVAL;
+
+ cpu = cpumask_first(partition->cpus);
+
+ /* CPU0 should be the only CPU in the mask */
+ if (cpu)
+ return -EINVAL;
+
+ for_each_possible_cpu(cpu) {
+ per_cpu(cpuoffline_partition, cpu) = partition;
+ cpumask_set_cpu(cpu, partition->cpus);
+ }
+
+ return 0;
+}
+
+int cpuoffline_default_driver_exit(struct cpuoffline_partition *partition)
+{
+ return 0;
+}
+
+static struct cpuoffline_driver cpuoffline_default_driver = {
+ .name = "default",
+ .init = cpuoffline_default_driver_init,
+ .exit = cpuoffline_default_driver_exit,
+};
+
+static int __init cpuoffline_register_default_driver(void)
+{
+ return cpuoffline_register_driver(&cpuoffline_default_driver);
+}
+late_initcall(cpuoffline_register_default_driver);
+#endif
+
+/* CPUoffline governor registration */
+int cpuoffline_register_governor(struct cpuoffline_governor *governor)
+{
+ int ret;
+
+ if (!governor)
+ return -EINVAL;
+
+ mutex_lock(&cpuoffline_governor_mutex);
+
+ ret = -EBUSY;
+ if (__find_governor(governor->name) == NULL) {
+ ret = 0;
+ list_add(&governor->governor_list, &cpuoffline_governor_list);
+ }
+
+ mutex_unlock(&cpuoffline_governor_mutex);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(cpuoffline_register_governor);
+
+
+/* CPUoffline core initialization */
+
+static int __init cpuoffline_core_init(void)
+{
+ int cpu;
+
+ pr_info("%s\n", __func__);
+ for_each_possible_cpu(cpu) {
+ per_cpu(cpuoffline_partition, cpu) = NULL;
+ }
+
+ cpuoffline_global_kobject = kobject_create_and_add("cpuoffline",
+ &cpu_sysdev_class.kset.kobj);
+
+ WARN_ON(!cpuoffline_global_kobject);
+ /*register_syscore_ops(&cpuoffline_syscore_ops);*/
+
+ return 0;
+}
+core_initcall(cpuoffline_core_init);
diff --git a/include/linux/cpuoffline.h b/include/linux/cpuoffline.h
new file mode 100644
index 0000000..0c5b9a5
--- /dev/null
+++ b/include/linux/cpuoffline.h
@@ -0,0 +1,82 @@
+/*
+ * cpuoffline.h
+ *
+ * Copyright (C) 2011 Texas Instruments, Inc.
+ * Mike Turquette <mturque...@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/cpu.h>
+#include <linux/mutex.h>
+
+#ifndef _LINUX_CPUOFFLINE_H
+#define _LINUX_CPUOFFLINE_H
+
+#define MAX_NAME_LEN 16
+
+//DECLARE_PER_CPU(struct cpuoffline_partition *, cpuoffline_partition);
+//DECLARE_PER_CPU(int, cpuoffline_can_offline);
+
+struct cpuoffline_partition;
+
+struct cpuoffline_governor {
+ char name[MAX_NAME_LEN];
+ struct list_head governor_list;
+ /*struct mutex mutex;*/
+ struct module *owner;
+ int (*start)(struct cpuoffline_partition *partition);
+ int (*stop)(struct cpuoffline_partition *partition);
+ struct kobject kobj;
+};
+
+/**
+ * cpuoffline_parition - set of CPUs affected by a CPUoffline governor
+ *
+ * @cpus - bitmask of CPUs managed by this partition
+ * @cpus_can_offline - bitmask of CPUs in this partition that can go offline
+ * @min_cpus_online - limit how many CPUs are offline for performance
+ * @max_cpus_online - limits how many CPUs are online for power capping
+ * @cpuoffline_governor - governor policy for hotplugging CPUs
+ */
+struct cpuoffline_partition {
+ int id;
+ char name[MAX_NAME_LEN];
+ cpumask_var_t cpus;
+ /*cpumask_var_t cpus_can_offline;*/
+ int min_cpus_online;
+ /*int max_cpus_online;*/
+ struct cpuoffline_governor *governor;
+
+ struct kobject kobj;
+ struct completion kobj_unregister;
+
+ struct mutex mutex;
+
+ void * private_data;
+};
+
+struct cpuoffline_driver {
+ char name[MAX_NAME_LEN];
+ int (*init)(struct cpuoffline_partition *partition);
+ int (*exit)(struct cpuoffline_partition *partition);
+};
+
+/* kobject/sysfs definitions */
+struct cpuoffline_attribute {
+ struct attribute attr;
+ ssize_t (*show)(struct cpuoffline_partition *partition, char *buf);
+ ssize_t (*store)(struct cpuoffline_partition *partition,
+ const char *buf, size_t count);
+};
+
+/* registration functions */
+
+int cpuoffline_register_governor(struct cpuoffline_governor *governor);
+void cpuoffline_unregister_governor(struct cpuoffline_governor *governor);
+
+int cpuoffline_register_driver(struct cpuoffline_driver *driver);
+int cpuoffline_unregister_driver(struct cpuoffline_driver *driver);
+#endif
--
1.7.4.1
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