/*
 * 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/slab.h>
#include <linux/cpu.h>
#include <linux/completion.h>
#include <linux/capability.h>
#include <linux/device.h>
#include <linux/kobject.h>

#include "cpuidle.h"

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 - (CPUIDLE_NAME_LEN + 2)))
                        goto out;

                i += sysfs_emit_at(buf, i, "%.*s ", CPUIDLE_NAME_LEN, tmp->name);
        }

out:
        i += sysfs_emit_at(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 *drv;

        spin_lock(&cpuidle_driver_lock);
        drv = cpuidle_get_driver();
        if (drv)
                ret = sysfs_emit(buf, "%s\n", drv->name);
        else
                ret = sysfs_emit(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 = sysfs_emit(buf, "%s\n", cpuidle_curr_governor->name);
        else
                ret = sysfs_emit(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 + 1];
        int ret;
        struct cpuidle_governor *gov;

        ret = sscanf(buf, "%" __stringify(CPUIDLE_NAME_LEN) "s", gov_name);
        if (ret != 1)
                return -EINVAL;

        mutex_lock(&cpuidle_lock);
        ret = -EINVAL;
        list_for_each_entry(gov, &cpuidle_governors, governor_list) {
                if (!strncmp(gov->name, gov_name, CPUIDLE_NAME_LEN)) {
                        ret = cpuidle_switch_governor(gov);
                        break;
                }
        }
        mutex_unlock(&cpuidle_lock);

        return ret ? ret : count;
}

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

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

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

/**
 * cpuidle_add_interface - add CPU global sysfs attributes
 */
int cpuidle_add_interface(void)
{
        struct device *dev_root = bus_get_dev_root(&cpu_subsys);
        int retval;

        if (!dev_root)
                return -EINVAL;

        retval = sysfs_create_group(&dev_root->kobj, &cpuidle_attr_group);
        put_device(dev_root);
        return retval;
}

/**
 * cpuidle_remove_interface - remove CPU global sysfs attributes
 * @dev: the target device
 */
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 attr_to_cpuidleattr(a) container_of(a, struct cpuidle_attr, attr)

struct cpuidle_device_kobj {
        struct cpuidle_device *dev;
        struct completion kobj_unregister;
        struct kobject kobj;
};

static inline struct cpuidle_device *to_cpuidle_device(struct kobject *kobj)
{
        struct cpuidle_device_kobj *kdev =
                container_of(kobj, struct cpuidle_device_kobj, kobj);

        return kdev->dev;
}

static ssize_t cpuidle_show(struct kobject *kobj, struct attribute *attr,
                            char *buf)
{
        int ret = -EIO;
        struct cpuidle_device *dev = to_cpuidle_device(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 = to_cpuidle_device(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_kobj *kdev =
                container_of(kobj, struct cpuidle_device_kobj, kobj);

        complete(&kdev->kobj_unregister);
}

static const 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 sysfs_emit(buf, "%u\n", state->_name);\
}

#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 sysfs_emit(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 sysfs_emit(buf, "<null>\n");\
        return sysfs_emit(buf, "%s\n", state->_name);\
}

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

define_show_state_time_function(exit_latency)
define_show_state_time_function(target_residency)
define_show_state_function(power_usage)
define_show_state_ull_function(usage)
define_show_state_ull_function(rejected)
define_show_state_str_function(name)
define_show_state_str_function(desc)
define_show_state_ull_function(above)
define_show_state_ull_function(below)

static ssize_t show_state_time(struct cpuidle_state *state,
                               struct cpuidle_state_usage *state_usage,
                               char *buf)
{
        return sysfs_emit(buf, "%llu\n", ktime_to_us(state_usage->time_ns));
}

static ssize_t show_state_disable(struct cpuidle_state *state,
                                  struct cpuidle_state_usage *state_usage,
                                  char *buf)
{
        return sysfs_emit(buf, "%llu\n",
                       state_usage->disable & CPUIDLE_STATE_DISABLED_BY_USER);
}

static ssize_t store_state_disable(struct cpuidle_state *state,
                                   struct cpuidle_state_usage *state_usage,
                                   const char *buf, size_t size)
{
        unsigned int value;
        int err;

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        err = kstrtouint(buf, 0, &value);
        if (err)
                return err;

        if (value)
                state_usage->disable |= CPUIDLE_STATE_DISABLED_BY_USER;
        else
                state_usage->disable &= ~CPUIDLE_STATE_DISABLED_BY_USER;

        return size;
}

static ssize_t show_state_default_status(struct cpuidle_state *state,
                                          struct cpuidle_state_usage *state_usage,
                                          char *buf)
{
        return sysfs_emit(buf, "%s\n",
                       state->flags & CPUIDLE_FLAG_OFF ? "disabled" : "enabled");
}

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(residency, show_state_target_residency);
define_one_state_ro(power, show_state_power_usage);
define_one_state_ro(usage, show_state_usage);
define_one_state_ro(rejected, show_state_rejected);
define_one_state_ro(time, show_state_time);
define_one_state_rw(disable, show_state_disable, store_state_disable);
define_one_state_ro(above, show_state_above);
define_one_state_ro(below, show_state_below);
define_one_state_ro(default_status, show_state_default_status);

static struct attribute *cpuidle_state_default_attrs[] = {
        &attr_name.attr,
        &attr_desc.attr,
        &attr_latency.attr,
        &attr_residency.attr,
        &attr_power.attr,
        &attr_usage.attr,
        &attr_rejected.attr,
        &attr_time.attr,
        &attr_disable.attr,
        &attr_above.attr,
        &attr_below.attr,
        &attr_default_status.attr,
        NULL
};
ATTRIBUTE_GROUPS(cpuidle_state_default);

struct cpuidle_state_kobj {
        struct cpuidle_state *state;
        struct cpuidle_state_usage *state_usage;
        struct completion kobj_unregister;
        struct kobject kobj;
        struct cpuidle_device *device;
};

#ifdef CONFIG_SUSPEND
#define define_show_state_s2idle_ull_function(_name) \
static ssize_t show_state_s2idle_##_name(struct cpuidle_state *state, \
                                         struct cpuidle_state_usage *state_usage, \
                                         char *buf)                             \
{ \
        return sysfs_emit(buf, "%llu\n", state_usage->s2idle_##_name);\
}

define_show_state_s2idle_ull_function(usage);
define_show_state_s2idle_ull_function(time);

#define define_one_state_s2idle_ro(_name, show) \
static struct cpuidle_state_attr attr_s2idle_##_name = \
        __ATTR(_name, 0444, show, NULL)

define_one_state_s2idle_ro(usage, show_state_s2idle_usage);
define_one_state_s2idle_ro(time, show_state_s2idle_time);

static struct attribute *cpuidle_state_s2idle_attrs[] = {
        &attr_s2idle_usage.attr,
        &attr_s2idle_time.attr,
        NULL
};

static const struct attribute_group cpuidle_state_s2idle_group = {
        .name   = "s2idle",
        .attrs  = cpuidle_state_s2idle_attrs,
};

static void cpuidle_add_s2idle_attr_group(struct cpuidle_state_kobj *kobj)
{
        int ret;

        if (!kobj->state->enter_s2idle)
                return;

        ret = sysfs_create_group(&kobj->kobj, &cpuidle_state_s2idle_group);
        if (ret)
                pr_debug("%s: sysfs attribute group not created\n", __func__);
}

static void cpuidle_remove_s2idle_attr_group(struct cpuidle_state_kobj *kobj)
{
        if (kobj->state->enter_s2idle)
                sysfs_remove_group(&kobj->kobj, &cpuidle_state_s2idle_group);
}
#else
static inline void cpuidle_add_s2idle_attr_group(struct cpuidle_state_kobj *kobj) { }
static inline void cpuidle_remove_s2idle_attr_group(struct cpuidle_state_kobj *kobj) { }
#endif /* CONFIG_SUSPEND */

#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 kobj_to_device(k) (kobj_to_state_obj(k)->device)
#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);
        struct cpuidle_device *dev = kobj_to_device(kobj);

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

        /* reset poll time cache */
        dev->poll_limit_ns = 0;

        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 const struct kobj_type ktype_state_cpuidle = {
        .sysfs_ops = &cpuidle_state_sysfs_ops,
        .default_groups = cpuidle_state_default_groups,
        .release = cpuidle_state_sysfs_release,
};

static inline void cpuidle_free_state_kobj(struct cpuidle_device *device, int i)
{
        cpuidle_remove_s2idle_attr_group(device->kobjs[i]);
        kobject_put(&device->kobjs[i]->kobj);
        wait_for_completion(&device->kobjs[i]->kobj_unregister);
        kfree(device->kobjs[i]);
        device->kobjs[i] = NULL;
}

/**
 * cpuidle_add_state_sysfs - adds cpuidle states sysfs attributes
 * @device: the target device
 */
static int cpuidle_add_state_sysfs(struct cpuidle_device *device)
{
        int i, ret = -ENOMEM;
        struct cpuidle_state_kobj *kobj;
        struct cpuidle_device_kobj *kdev = device->kobj_dev;
        struct cpuidle_driver *drv = cpuidle_get_cpu_driver(device);

        /* state statistics */
        for (i = 0; i < drv->state_count; i++) {
                kobj = kzalloc_obj(struct cpuidle_state_kobj);
                if (!kobj) {
                        ret = -ENOMEM;
                        goto error_state;
                }
                kobj->state = &drv->states[i];
                kobj->state_usage = &device->states_usage[i];
                kobj->device = device;
                init_completion(&kobj->kobj_unregister);

                ret = kobject_init_and_add(&kobj->kobj, &ktype_state_cpuidle,
                                           &kdev->kobj, "state%d", i);
                if (ret) {
                        kobject_put(&kobj->kobj);
                        kfree(kobj);
                        goto error_state;
                }
                cpuidle_add_s2idle_attr_group(kobj);
                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;
}

/**
 * cpuidle_remove_state_sysfs - removes the cpuidle states sysfs attributes
 * @device: the target device
 */
static void cpuidle_remove_state_sysfs(struct cpuidle_device *device)
{
        struct cpuidle_driver *drv = cpuidle_get_cpu_driver(device);
        int i;

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

#ifdef CONFIG_CPU_IDLE_MULTIPLE_DRIVERS
#define kobj_to_driver_kobj(k) container_of(k, struct cpuidle_driver_kobj, kobj)
#define attr_to_driver_attr(a) container_of(a, struct cpuidle_driver_attr, attr)

#define define_one_driver_ro(_name, show)                       \
        static struct cpuidle_driver_attr attr_driver_##_name = \
                __ATTR(_name, 0444, show, NULL)

struct cpuidle_driver_kobj {
        struct cpuidle_driver *drv;
        struct completion kobj_unregister;
        struct kobject kobj;
};

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

static ssize_t show_driver_name(struct cpuidle_driver *drv, char *buf)
{
        ssize_t ret;

        spin_lock(&cpuidle_driver_lock);
        ret = sysfs_emit(buf, "%s\n", drv ? drv->name : "none");
        spin_unlock(&cpuidle_driver_lock);

        return ret;
}

static void cpuidle_driver_sysfs_release(struct kobject *kobj)
{
        struct cpuidle_driver_kobj *driver_kobj = kobj_to_driver_kobj(kobj);
        complete(&driver_kobj->kobj_unregister);
}

static ssize_t cpuidle_driver_show(struct kobject *kobj, struct attribute *attr,
                                   char *buf)
{
        int ret = -EIO;
        struct cpuidle_driver_kobj *driver_kobj = kobj_to_driver_kobj(kobj);
        struct cpuidle_driver_attr *dattr = attr_to_driver_attr(attr);

        if (dattr->show)
                ret = dattr->show(driver_kobj->drv, buf);

        return ret;
}

static ssize_t cpuidle_driver_store(struct kobject *kobj, struct attribute *attr,
                                    const char *buf, size_t size)
{
        int ret = -EIO;
        struct cpuidle_driver_kobj *driver_kobj = kobj_to_driver_kobj(kobj);
        struct cpuidle_driver_attr *dattr = attr_to_driver_attr(attr);

        if (dattr->store)
                ret = dattr->store(driver_kobj->drv, buf, size);

        return ret;
}

define_one_driver_ro(name, show_driver_name);

static const struct sysfs_ops cpuidle_driver_sysfs_ops = {
        .show = cpuidle_driver_show,
        .store = cpuidle_driver_store,
};

static struct attribute *cpuidle_driver_default_attrs[] = {
        &attr_driver_name.attr,
        NULL
};
ATTRIBUTE_GROUPS(cpuidle_driver_default);

static const struct kobj_type ktype_driver_cpuidle = {
        .sysfs_ops = &cpuidle_driver_sysfs_ops,
        .default_groups = cpuidle_driver_default_groups,
        .release = cpuidle_driver_sysfs_release,
};

/**
 * cpuidle_add_driver_sysfs - adds the driver name sysfs attribute
 * @dev: the target device
 */
static int cpuidle_add_driver_sysfs(struct cpuidle_device *dev)
{
        struct cpuidle_driver_kobj *kdrv;
        struct cpuidle_device_kobj *kdev = dev->kobj_dev;
        struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
        int ret;

        kdrv = kzalloc_obj(*kdrv);
        if (!kdrv)
                return -ENOMEM;

        kdrv->drv = drv;
        init_completion(&kdrv->kobj_unregister);

        ret = kobject_init_and_add(&kdrv->kobj, &ktype_driver_cpuidle,
                                   &kdev->kobj, "driver");
        if (ret) {
                kobject_put(&kdrv->kobj);
                kfree(kdrv);
                return ret;
        }

        kobject_uevent(&kdrv->kobj, KOBJ_ADD);
        dev->kobj_driver = kdrv;

        return ret;
}

/**
 * cpuidle_remove_driver_sysfs - removes the driver name sysfs attribute
 * @dev: the target device
 */
static void cpuidle_remove_driver_sysfs(struct cpuidle_device *dev)
{
        struct cpuidle_driver_kobj *kdrv = dev->kobj_driver;
        kobject_put(&kdrv->kobj);
        wait_for_completion(&kdrv->kobj_unregister);
        kfree(kdrv);
}
#else
static inline int cpuidle_add_driver_sysfs(struct cpuidle_device *dev)
{
        return 0;
}

static inline void cpuidle_remove_driver_sysfs(struct cpuidle_device *dev)
{
        ;
}
#endif

/**
 * cpuidle_add_device_sysfs - adds device specific sysfs attributes
 * @device: the target device
 */
int cpuidle_add_device_sysfs(struct cpuidle_device *device)
{
        int ret;

        ret = cpuidle_add_state_sysfs(device);
        if (ret)
                return ret;

        ret = cpuidle_add_driver_sysfs(device);
        if (ret)
                cpuidle_remove_state_sysfs(device);
        return ret;
}

/**
 * cpuidle_remove_device_sysfs : removes device specific sysfs attributes
 * @device : the target device
 */
void cpuidle_remove_device_sysfs(struct cpuidle_device *device)
{
        cpuidle_remove_driver_sysfs(device);
        cpuidle_remove_state_sysfs(device);
}

/**
 * cpuidle_add_sysfs - creates a sysfs instance for the target device
 * @dev: the target device
 */
int cpuidle_add_sysfs(struct cpuidle_device *dev)
{
        struct cpuidle_device_kobj *kdev;
        struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu);
        int error;

        /*
         * Return if cpu_device is not setup for this CPU.
         *
         * This could happen if the arch did not set up cpu_device
         * since this CPU is not in cpu_present mask and the
         * driver did not send a correct CPU mask during registration.
         * Without this check we would end up passing bogus
         * value for &cpu_dev->kobj in kobject_init_and_add()
         */
        if (!cpu_dev)
                return -ENODEV;

        kdev = kzalloc_obj(*kdev);
        if (!kdev)
                return -ENOMEM;
        kdev->dev = dev;

        init_completion(&kdev->kobj_unregister);

        error = kobject_init_and_add(&kdev->kobj, &ktype_cpuidle, &cpu_dev->kobj,
                                   "cpuidle");
        if (error) {
                kobject_put(&kdev->kobj);
                kfree(kdev);
                return error;
        }

        dev->kobj_dev = kdev;
        kobject_uevent(&kdev->kobj, KOBJ_ADD);

        return 0;
}

/**
 * cpuidle_remove_sysfs - deletes a sysfs instance on the target device
 * @dev: the target device
 */
void cpuidle_remove_sysfs(struct cpuidle_device *dev)
{
        struct cpuidle_device_kobj *kdev = dev->kobj_dev;

        kobject_put(&kdev->kobj);
        wait_for_completion(&kdev->kobj_unregister);
        kfree(kdev);
}