sysfs.c

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/*
 * sysfs.c - sysfs support
 *
 * (C) 2006-2007 Shaohua Li <[email protected]>
 *
 * This code is licenced under the GPL.
 */

#include <linux/kernel.h>
#include <linux/cpuidle.h>
#include <linux/sysfs.h>
#include <linux/slab.h>
#include <linux/cpu.h>
#include <linux/capability.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 device *dev,
                    struct device_attribute *attr,
                    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 device *dev,
                   struct device_attribute *attr,
                   char *buf)
{
    ssize_t ret;
    struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();

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

    return ret;
}

static ssize_t show_current_governor(struct device *dev,
                     struct device_attribute *attr,
                     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 device *dev,
                      struct device_attribute *attr,
                      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 DEVICE_ATTR(current_driver, 0444, show_current_driver, NULL);
static DEVICE_ATTR(current_governor_ro, 0444, show_current_governor, NULL);

static struct attribute *cpuidle_default_attrs[] = {
    &dev_attr_current_driver.attr,
    &dev_attr_current_governor_ro.attr,
    NULL
};

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

static struct attribute *cpuidle_switch_attrs[] = {
    &dev_attr_available_governors.attr,
    &dev_attr_current_driver.attr,
    &dev_attr_current_governor.attr,
    NULL
};

static struct attribute_group cpuidle_attr_group = {
    .attrs = cpuidle_default_attrs,
    .name = "cpuidle",
};

int cpuidle_add_interface(struct device *dev)
{
    if (sysfs_switch)
        cpuidle_attr_group.attrs = cpuidle_switch_attrs;

    return sysfs_create_group(&dev->kobj, &cpuidle_attr_group);
}

void cpuidle_remove_interface(struct device *dev)
{
    sysfs_remove_group(&dev->kobj, &cpuidle_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 const 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 *, \
					struct cpuidle_state_usage *, char *);
    ssize_t (*store)(struct cpuidle_state *, \
			struct cpuidle_state_usage *, 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_one_state_rw(_name, show, store) \
static struct cpuidle_state_attr attr_##_name = __ATTR(_name, 0644, show, store)

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

#define define_store_state_ull_function(_name) \
static ssize_t store_state_##_name(struct cpuidle_state *state, \
        struct cpuidle_state_usage *state_usage, \
        const char *buf, size_t size) \
{ \
    unsigned long long value; \
    int err; \
    if (!capable(CAP_SYS_ADMIN)) \
        return -EPERM; \
    err = kstrtoull(buf, 0, &value); \
    if (err) \
        return err; \
    if (value) \
        state_usage->_name = 1; \
    else \
        state_usage->_name = 0; \
    return size; \
}

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

#define define_show_state_str_function(_name) \
static ssize_t show_state_##_name(struct cpuidle_state *state, \
            struct cpuidle_state_usage *state_usage, char *buf) \
{ \
    if (state->_name[0] == '\0')\
        return sprintf(buf, "<null>\n");\
    return sprintf(buf, "%s\n", state->_name);\
}

define_show_state_function(exit_latency)
define_show_state_function(power_usage)
define_show_state_ull_function(usage)
define_show_state_ull_function(time)
define_show_state_str_function(name)
define_show_state_str_function(desc)
define_show_state_ull_function(disable)
define_store_state_ull_function(disable)

define_one_state_ro(name, show_state_name);
define_one_state_ro(desc, show_state_desc);
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);
define_one_state_rw(disable, show_state_disable, store_state_disable);

static struct attribute *cpuidle_state_default_attrs[] = {
    &attr_name.attr,
    &attr_desc.attr,
    &attr_latency.attr,
    &attr_power.attr,
    &attr_usage.attr,
    &attr_time.attr,
    &attr_disable.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 kobj_to_state_usage(k) (kobj_to_state_obj(k)->state_usage)
#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_usage *state_usage = kobj_to_state_usage(kobj);
    struct cpuidle_state_attr * cattr = attr_to_stateattr(attr);

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

    return ret;
}

static ssize_t cpuidle_state_store(struct kobject *kobj,
    struct attribute *attr, const char *buf, size_t size)
{
    int ret = -EIO;
    struct cpuidle_state *state = kobj_to_state(kobj);
    struct cpuidle_state_usage *state_usage = kobj_to_state_usage(kobj);
    struct cpuidle_state_attr *cattr = attr_to_stateattr(attr);

    if (cattr->store)
        ret = cattr->store(state, state_usage, buf, size);

    return ret;
}

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

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

int cpuidle_add_state_sysfs(struct cpuidle_device *device)
{
    int i, ret = -ENOMEM;
    struct cpuidle_state_kobj *kobj;
    struct cpuidle_driver *drv = cpuidle_get_driver();

    /* 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 = &drv->states[i];
        kobj->state_usage = &device->states_usage[i];
        init_completion(&kobj->kobj_unregister);

        ret = kobject_init_and_add(&kobj->kobj, &ktype_state_cpuidle, &device->kobj,
                       "state%d", i);
        if (ret) {
            kfree(kobj);
            goto error_state;
        }
        kobject_uevent(&kobj->kobj, KOBJ_ADD);
        device->kobjs[i] = kobj;
    }

    return 0;

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

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);
}

int cpuidle_add_sysfs(struct device *cpu_dev)
{
    int cpu = cpu_dev->id;
    struct cpuidle_device *dev;
    int error;

    dev = per_cpu(cpuidle_devices, cpu);
    error = kobject_init_and_add(&dev->kobj, &ktype_cpuidle, &cpu_dev->kobj,
                     "cpuidle");
    if (!error)
        kobject_uevent(&dev->kobj, KOBJ_ADD);
    return error;
}

void cpuidle_remove_sysfs(struct device *cpu_dev)
{
    int cpu = cpu_dev->id;
    struct cpuidle_device *dev;

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