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sysfs.c

/*
 * sysfs.c - sysfs support
 *
 * (C) 2006-2007 Shaohua Li <shaohua.li@intel.com>
 *
 * This code is licenced under the GPL.
 */

#include <linux/kernel.h>
#include <linux/cpuidle.h>
#include <linux/sysfs.h>
#include <linux/cpu.h>

#include "cpuidle.h"

static unsigned int sysfs_switch;
static int __init cpuidle_sysfs_setup(char *unused)
{
      sysfs_switch = 1;
      return 1;
}
__setup("cpuidle_sysfs_switch", cpuidle_sysfs_setup);

static ssize_t show_available_governors(struct sys_device *dev, char *buf)
{
      ssize_t i = 0;
      struct cpuidle_governor *tmp;

      mutex_lock(&cpuidle_lock);
      list_for_each_entry(tmp, &cpuidle_governors, governor_list) {
            if (i >= (ssize_t) ((PAGE_SIZE/sizeof(char)) - CPUIDLE_NAME_LEN - 2))
                  goto out;
            i += scnprintf(&buf[i], CPUIDLE_NAME_LEN, "%s ", tmp->name);
      }

out:
      i+= sprintf(&buf[i], "\n");
      mutex_unlock(&cpuidle_lock);
      return i;
}

static ssize_t show_current_driver(struct sys_device *dev, char *buf)
{
      ssize_t ret;

      spin_lock(&cpuidle_driver_lock);
      if (cpuidle_curr_driver)
            ret = sprintf(buf, "%s\n", cpuidle_curr_driver->name);
      else
            ret = sprintf(buf, "none\n");
      spin_unlock(&cpuidle_driver_lock);

      return ret;
}

static ssize_t show_current_governor(struct sys_device *dev, char *buf)
{
      ssize_t ret;

      mutex_lock(&cpuidle_lock);
      if (cpuidle_curr_governor)
            ret = sprintf(buf, "%s\n", cpuidle_curr_governor->name);
      else
            ret = sprintf(buf, "none\n");
      mutex_unlock(&cpuidle_lock);

      return ret;
}

static ssize_t store_current_governor(struct sys_device *dev,
      const char *buf, size_t count)
{
      char gov_name[CPUIDLE_NAME_LEN];
      int ret = -EINVAL;
      size_t len = count;
      struct cpuidle_governor *gov;

      if (!len || len >= sizeof(gov_name))
            return -EINVAL;

      memcpy(gov_name, buf, len);
      gov_name[len] = '\0';
      if (gov_name[len - 1] == '\n')
            gov_name[--len] = '\0';

      mutex_lock(&cpuidle_lock);

      list_for_each_entry(gov, &cpuidle_governors, governor_list) {
            if (strlen(gov->name) == len && !strcmp(gov->name, gov_name)) {
                  ret = cpuidle_switch_governor(gov);
                  break;
            }
      }

      mutex_unlock(&cpuidle_lock);

      if (ret)
            return ret;
      else
            return count;
}

static SYSDEV_ATTR(current_driver, 0444, show_current_driver, NULL);
static SYSDEV_ATTR(current_governor_ro, 0444, show_current_governor, NULL);

static struct attribute *cpuclass_default_attrs[] = {
      &attr_current_driver.attr,
      &attr_current_governor_ro.attr,
      NULL
};

static SYSDEV_ATTR(available_governors, 0444, show_available_governors, NULL);
static SYSDEV_ATTR(current_governor, 0644, show_current_governor,
      store_current_governor);

static struct attribute *cpuclass_switch_attrs[] = {
      &attr_available_governors.attr,
      &attr_current_driver.attr,
      &attr_current_governor.attr,
      NULL
};

static struct attribute_group cpuclass_attr_group = {
      .attrs = cpuclass_default_attrs,
      .name = "cpuidle",
};

/**
 * cpuidle_add_class_sysfs - add CPU global sysfs attributes
 */
int cpuidle_add_class_sysfs(struct sysdev_class *cls)
{
      if (sysfs_switch)
            cpuclass_attr_group.attrs = cpuclass_switch_attrs;

      return sysfs_create_group(&cls->kset.kobj, &cpuclass_attr_group);
}

/**
 * cpuidle_remove_class_sysfs - remove CPU global sysfs attributes
 */
void cpuidle_remove_class_sysfs(struct sysdev_class *cls)
{
      sysfs_remove_group(&cls->kset.kobj, &cpuclass_attr_group);
}

struct cpuidle_attr {
      struct attribute attr;
      ssize_t (*show)(struct cpuidle_device *, char *);
      ssize_t (*store)(struct cpuidle_device *, const char *, size_t count);
};

#define define_one_ro(_name, show) \
      static struct cpuidle_attr attr_##_name = __ATTR(_name, 0444, show, NULL)
#define define_one_rw(_name, show, store) \
      static struct cpuidle_attr attr_##_name = __ATTR(_name, 0644, show, store)

#define kobj_to_cpuidledev(k) container_of(k, struct cpuidle_device, kobj)
#define attr_to_cpuidleattr(a) container_of(a, struct cpuidle_attr, attr)
static ssize_t cpuidle_show(struct kobject * kobj, struct attribute * attr ,char * buf)
{
      int ret = -EIO;
      struct cpuidle_device *dev = kobj_to_cpuidledev(kobj);
      struct cpuidle_attr * cattr = attr_to_cpuidleattr(attr);

      if (cattr->show) {
            mutex_lock(&cpuidle_lock);
            ret = cattr->show(dev, buf);
            mutex_unlock(&cpuidle_lock);
      }
      return ret;
}

static ssize_t cpuidle_store(struct kobject * kobj, struct attribute * attr,
                 const char * buf, size_t count)
{
      int ret = -EIO;
      struct cpuidle_device *dev = kobj_to_cpuidledev(kobj);
      struct cpuidle_attr * cattr = attr_to_cpuidleattr(attr);

      if (cattr->store) {
            mutex_lock(&cpuidle_lock);
            ret = cattr->store(dev, buf, count);
            mutex_unlock(&cpuidle_lock);
      }
      return ret;
}

static struct sysfs_ops cpuidle_sysfs_ops = {
      .show = cpuidle_show,
      .store = cpuidle_store,
};

static void cpuidle_sysfs_release(struct kobject *kobj)
{
      struct cpuidle_device *dev = kobj_to_cpuidledev(kobj);

      complete(&dev->kobj_unregister);
}

static struct kobj_type ktype_cpuidle = {
      .sysfs_ops = &cpuidle_sysfs_ops,
      .release = cpuidle_sysfs_release,
};

struct cpuidle_state_attr {
      struct attribute attr;
      ssize_t (*show)(struct cpuidle_state *, char *);
      ssize_t (*store)(struct cpuidle_state *, const char *, size_t);
};

#define define_one_state_ro(_name, show) \
static struct cpuidle_state_attr attr_##_name = __ATTR(_name, 0444, show, NULL)

#define define_show_state_function(_name) \
static ssize_t show_state_##_name(struct cpuidle_state *state, char *buf) \
{ \
      return sprintf(buf, "%u\n", state->_name);\
}

static ssize_t show_state_name(struct cpuidle_state *state, char *buf)
{
      return sprintf(buf, "%s\n", state->name);
}

define_show_state_function(exit_latency)
define_show_state_function(power_usage)
define_show_state_function(usage)
define_show_state_function(time)
define_one_state_ro(name, show_state_name);
define_one_state_ro(latency, show_state_exit_latency);
define_one_state_ro(power, show_state_power_usage);
define_one_state_ro(usage, show_state_usage);
define_one_state_ro(time, show_state_time);

static struct attribute *cpuidle_state_default_attrs[] = {
      &attr_name.attr,
      &attr_latency.attr,
      &attr_power.attr,
      &attr_usage.attr,
      &attr_time.attr,
      NULL
};

#define kobj_to_state_obj(k) container_of(k, struct cpuidle_state_kobj, kobj)
#define kobj_to_state(k) (kobj_to_state_obj(k)->state)
#define attr_to_stateattr(a) container_of(a, struct cpuidle_state_attr, attr)
static ssize_t cpuidle_state_show(struct kobject * kobj,
      struct attribute * attr ,char * buf)
{
      int ret = -EIO;
      struct cpuidle_state *state = kobj_to_state(kobj);
      struct cpuidle_state_attr * cattr = attr_to_stateattr(attr);

      if (cattr->show)
            ret = cattr->show(state, buf);

      return ret;
}

static struct sysfs_ops cpuidle_state_sysfs_ops = {
      .show = cpuidle_state_show,
};

static void cpuidle_state_sysfs_release(struct kobject *kobj)
{
      struct cpuidle_state_kobj *state_obj = kobj_to_state_obj(kobj);

      complete(&state_obj->kobj_unregister);
}

static struct kobj_type ktype_state_cpuidle = {
      .sysfs_ops = &cpuidle_state_sysfs_ops,
      .default_attrs = cpuidle_state_default_attrs,
      .release = cpuidle_state_sysfs_release,
};

static void inline cpuidle_free_state_kobj(struct cpuidle_device *device, int i)
{
      kobject_unregister(&device->kobjs[i]->kobj);
      wait_for_completion(&device->kobjs[i]->kobj_unregister);
      kfree(device->kobjs[i]);
      device->kobjs[i] = NULL;
}

/**
 * cpuidle_add_driver_sysfs - adds driver-specific sysfs attributes
 * @device: the target device
 */
int cpuidle_add_state_sysfs(struct cpuidle_device *device)
{
      int i, ret = -ENOMEM;
      struct cpuidle_state_kobj *kobj;

      /* state statistics */
      for (i = 0; i < device->state_count; i++) {
            kobj = kzalloc(sizeof(struct cpuidle_state_kobj), GFP_KERNEL);
            if (!kobj)
                  goto error_state;
            kobj->state = &device->states[i];
            init_completion(&kobj->kobj_unregister);

            kobj->kobj.parent = &device->kobj;
            kobj->kobj.ktype = &ktype_state_cpuidle;
            kobject_set_name(&kobj->kobj, "state%d", i);
            ret = kobject_register(&kobj->kobj);
            if (ret) {
                  kfree(kobj);
                  goto error_state;
            }
            device->kobjs[i] = kobj;
      }

      return 0;

error_state:
      for (i = i - 1; i >= 0; i--)
            cpuidle_free_state_kobj(device, i);
      return ret;
}

/**
 * cpuidle_remove_driver_sysfs - removes driver-specific sysfs attributes
 * @device: the target device
 */
void cpuidle_remove_state_sysfs(struct cpuidle_device *device)
{
      int i;

      for (i = 0; i < device->state_count; i++)
            cpuidle_free_state_kobj(device, i);
}

/**
 * cpuidle_add_sysfs - creates a sysfs instance for the target device
 * @sysdev: the target device
 */
int cpuidle_add_sysfs(struct sys_device *sysdev)
{
      int cpu = sysdev->id;
      struct cpuidle_device *dev;

      dev = per_cpu(cpuidle_devices, cpu);
      dev->kobj.parent = &sysdev->kobj;
      dev->kobj.ktype = &ktype_cpuidle;
      kobject_set_name(&dev->kobj, "%s", "cpuidle");
      return kobject_register(&dev->kobj);
}

/**
 * cpuidle_remove_sysfs - deletes a sysfs instance on the target device
 * @sysdev: the target device
 */
void cpuidle_remove_sysfs(struct sys_device *sysdev)
{
      int cpu = sysdev->id;
      struct cpuidle_device *dev;

      dev = per_cpu(cpuidle_devices, cpu);
      kobject_unregister(&dev->kobj);
}

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