linux/drivers/cpuidle/sysfs.c
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   1/*
   2 * sysfs.c - sysfs support
   3 *
   4 * (C) 2006-2007 Shaohua Li <shaohua.li@intel.com>
   5 *
   6 * This code is licenced under the GPL.
   7 */
   8
   9#include <linux/kernel.h>
  10#include <linux/cpuidle.h>
  11#include <linux/sysfs.h>
  12#include <linux/slab.h>
  13#include <linux/cpu.h>
  14
  15#include "cpuidle.h"
  16
  17static unsigned int sysfs_switch;
  18static int __init cpuidle_sysfs_setup(char *unused)
  19{
  20        sysfs_switch = 1;
  21        return 1;
  22}
  23__setup("cpuidle_sysfs_switch", cpuidle_sysfs_setup);
  24
  25static ssize_t show_available_governors(struct sysdev_class *class,
  26                                        struct sysdev_class_attribute *attr,
  27                                        char *buf)
  28{
  29        ssize_t i = 0;
  30        struct cpuidle_governor *tmp;
  31
  32        mutex_lock(&cpuidle_lock);
  33        list_for_each_entry(tmp, &cpuidle_governors, governor_list) {
  34                if (i >= (ssize_t) ((PAGE_SIZE/sizeof(char)) - CPUIDLE_NAME_LEN - 2))
  35                        goto out;
  36                i += scnprintf(&buf[i], CPUIDLE_NAME_LEN, "%s ", tmp->name);
  37        }
  38
  39out:
  40        i+= sprintf(&buf[i], "\n");
  41        mutex_unlock(&cpuidle_lock);
  42        return i;
  43}
  44
  45static ssize_t show_current_driver(struct sysdev_class *class,
  46                                   struct sysdev_class_attribute *attr,
  47                                   char *buf)
  48{
  49        ssize_t ret;
  50        struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
  51
  52        spin_lock(&cpuidle_driver_lock);
  53        if (cpuidle_driver)
  54                ret = sprintf(buf, "%s\n", cpuidle_driver->name);
  55        else
  56                ret = sprintf(buf, "none\n");
  57        spin_unlock(&cpuidle_driver_lock);
  58
  59        return ret;
  60}
  61
  62static ssize_t show_current_governor(struct sysdev_class *class,
  63                                     struct sysdev_class_attribute *attr,
  64                                     char *buf)
  65{
  66        ssize_t ret;
  67
  68        mutex_lock(&cpuidle_lock);
  69        if (cpuidle_curr_governor)
  70                ret = sprintf(buf, "%s\n", cpuidle_curr_governor->name);
  71        else
  72                ret = sprintf(buf, "none\n");
  73        mutex_unlock(&cpuidle_lock);
  74
  75        return ret;
  76}
  77
  78static ssize_t store_current_governor(struct sysdev_class *class,
  79                                      struct sysdev_class_attribute *attr,
  80                                      const char *buf, size_t count)
  81{
  82        char gov_name[CPUIDLE_NAME_LEN];
  83        int ret = -EINVAL;
  84        size_t len = count;
  85        struct cpuidle_governor *gov;
  86
  87        if (!len || len >= sizeof(gov_name))
  88                return -EINVAL;
  89
  90        memcpy(gov_name, buf, len);
  91        gov_name[len] = '\0';
  92        if (gov_name[len - 1] == '\n')
  93                gov_name[--len] = '\0';
  94
  95        mutex_lock(&cpuidle_lock);
  96
  97        list_for_each_entry(gov, &cpuidle_governors, governor_list) {
  98                if (strlen(gov->name) == len && !strcmp(gov->name, gov_name)) {
  99                        ret = cpuidle_switch_governor(gov);
 100                        break;
 101                }
 102        }
 103
 104        mutex_unlock(&cpuidle_lock);
 105
 106        if (ret)
 107                return ret;
 108        else
 109                return count;
 110}
 111
 112static SYSDEV_CLASS_ATTR(current_driver, 0444, show_current_driver, NULL);
 113static SYSDEV_CLASS_ATTR(current_governor_ro, 0444, show_current_governor,
 114                         NULL);
 115
 116static struct attribute *cpuclass_default_attrs[] = {
 117        &attr_current_driver.attr,
 118        &attr_current_governor_ro.attr,
 119        NULL
 120};
 121
 122static SYSDEV_CLASS_ATTR(available_governors, 0444, show_available_governors,
 123                         NULL);
 124static SYSDEV_CLASS_ATTR(current_governor, 0644, show_current_governor,
 125                         store_current_governor);
 126
 127static struct attribute *cpuclass_switch_attrs[] = {
 128        &attr_available_governors.attr,
 129        &attr_current_driver.attr,
 130        &attr_current_governor.attr,
 131        NULL
 132};
 133
 134static struct attribute_group cpuclass_attr_group = {
 135        .attrs = cpuclass_default_attrs,
 136        .name = "cpuidle",
 137};
 138
 139/**
 140 * cpuidle_add_class_sysfs - add CPU global sysfs attributes
 141 */
 142int cpuidle_add_class_sysfs(struct sysdev_class *cls)
 143{
 144        if (sysfs_switch)
 145                cpuclass_attr_group.attrs = cpuclass_switch_attrs;
 146
 147        return sysfs_create_group(&cls->kset.kobj, &cpuclass_attr_group);
 148}
 149
 150/**
 151 * cpuidle_remove_class_sysfs - remove CPU global sysfs attributes
 152 */
 153void cpuidle_remove_class_sysfs(struct sysdev_class *cls)
 154{
 155        sysfs_remove_group(&cls->kset.kobj, &cpuclass_attr_group);
 156}
 157
 158struct cpuidle_attr {
 159        struct attribute attr;
 160        ssize_t (*show)(struct cpuidle_device *, char *);
 161        ssize_t (*store)(struct cpuidle_device *, const char *, size_t count);
 162};
 163
 164#define define_one_ro(_name, show) \
 165        static struct cpuidle_attr attr_##_name = __ATTR(_name, 0444, show, NULL)
 166#define define_one_rw(_name, show, store) \
 167        static struct cpuidle_attr attr_##_name = __ATTR(_name, 0644, show, store)
 168
 169#define kobj_to_cpuidledev(k) container_of(k, struct cpuidle_device, kobj)
 170#define attr_to_cpuidleattr(a) container_of(a, struct cpuidle_attr, attr)
 171static ssize_t cpuidle_show(struct kobject * kobj, struct attribute * attr ,char * buf)
 172{
 173        int ret = -EIO;
 174        struct cpuidle_device *dev = kobj_to_cpuidledev(kobj);
 175        struct cpuidle_attr * cattr = attr_to_cpuidleattr(attr);
 176
 177        if (cattr->show) {
 178                mutex_lock(&cpuidle_lock);
 179                ret = cattr->show(dev, buf);
 180                mutex_unlock(&cpuidle_lock);
 181        }
 182        return ret;
 183}
 184
 185static ssize_t cpuidle_store(struct kobject * kobj, struct attribute * attr,
 186                     const char * buf, size_t count)
 187{
 188        int ret = -EIO;
 189        struct cpuidle_device *dev = kobj_to_cpuidledev(kobj);
 190        struct cpuidle_attr * cattr = attr_to_cpuidleattr(attr);
 191
 192        if (cattr->store) {
 193                mutex_lock(&cpuidle_lock);
 194                ret = cattr->store(dev, buf, count);
 195                mutex_unlock(&cpuidle_lock);
 196        }
 197        return ret;
 198}
 199
 200static const struct sysfs_ops cpuidle_sysfs_ops = {
 201        .show = cpuidle_show,
 202        .store = cpuidle_store,
 203};
 204
 205static void cpuidle_sysfs_release(struct kobject *kobj)
 206{
 207        struct cpuidle_device *dev = kobj_to_cpuidledev(kobj);
 208
 209        complete(&dev->kobj_unregister);
 210}
 211
 212static struct kobj_type ktype_cpuidle = {
 213        .sysfs_ops = &cpuidle_sysfs_ops,
 214        .release = cpuidle_sysfs_release,
 215};
 216
 217struct cpuidle_state_attr {
 218        struct attribute attr;
 219        ssize_t (*show)(struct cpuidle_state *, char *);
 220        ssize_t (*store)(struct cpuidle_state *, const char *, size_t);
 221};
 222
 223#define define_one_state_ro(_name, show) \
 224static struct cpuidle_state_attr attr_##_name = __ATTR(_name, 0444, show, NULL)
 225
 226#define define_show_state_function(_name) \
 227static ssize_t show_state_##_name(struct cpuidle_state *state, char *buf) \
 228{ \
 229        return sprintf(buf, "%u\n", state->_name);\
 230}
 231
 232#define define_show_state_ull_function(_name) \
 233static ssize_t show_state_##_name(struct cpuidle_state *state, char *buf) \
 234{ \
 235        return sprintf(buf, "%llu\n", state->_name);\
 236}
 237
 238#define define_show_state_str_function(_name) \
 239static ssize_t show_state_##_name(struct cpuidle_state *state, char *buf) \
 240{ \
 241        if (state->_name[0] == '\0')\
 242                return sprintf(buf, "<null>\n");\
 243        return sprintf(buf, "%s\n", state->_name);\
 244}
 245
 246define_show_state_function(exit_latency)
 247define_show_state_function(power_usage)
 248define_show_state_ull_function(usage)
 249define_show_state_ull_function(time)
 250define_show_state_str_function(name)
 251define_show_state_str_function(desc)
 252
 253define_one_state_ro(name, show_state_name);
 254define_one_state_ro(desc, show_state_desc);
 255define_one_state_ro(latency, show_state_exit_latency);
 256define_one_state_ro(power, show_state_power_usage);
 257define_one_state_ro(usage, show_state_usage);
 258define_one_state_ro(time, show_state_time);
 259
 260static struct attribute *cpuidle_state_default_attrs[] = {
 261        &attr_name.attr,
 262        &attr_desc.attr,
 263        &attr_latency.attr,
 264        &attr_power.attr,
 265        &attr_usage.attr,
 266        &attr_time.attr,
 267        NULL
 268};
 269
 270#define kobj_to_state_obj(k) container_of(k, struct cpuidle_state_kobj, kobj)
 271#define kobj_to_state(k) (kobj_to_state_obj(k)->state)
 272#define attr_to_stateattr(a) container_of(a, struct cpuidle_state_attr, attr)
 273static ssize_t cpuidle_state_show(struct kobject * kobj,
 274        struct attribute * attr ,char * buf)
 275{
 276        int ret = -EIO;
 277        struct cpuidle_state *state = kobj_to_state(kobj);
 278        struct cpuidle_state_attr * cattr = attr_to_stateattr(attr);
 279
 280        if (cattr->show)
 281                ret = cattr->show(state, buf);
 282
 283        return ret;
 284}
 285
 286static const struct sysfs_ops cpuidle_state_sysfs_ops = {
 287        .show = cpuidle_state_show,
 288};
 289
 290static void cpuidle_state_sysfs_release(struct kobject *kobj)
 291{
 292        struct cpuidle_state_kobj *state_obj = kobj_to_state_obj(kobj);
 293
 294        complete(&state_obj->kobj_unregister);
 295}
 296
 297static struct kobj_type ktype_state_cpuidle = {
 298        .sysfs_ops = &cpuidle_state_sysfs_ops,
 299        .default_attrs = cpuidle_state_default_attrs,
 300        .release = cpuidle_state_sysfs_release,
 301};
 302
 303static inline void cpuidle_free_state_kobj(struct cpuidle_device *device, int i)
 304{
 305        kobject_put(&device->kobjs[i]->kobj);
 306        wait_for_completion(&device->kobjs[i]->kobj_unregister);
 307        kfree(device->kobjs[i]);
 308        device->kobjs[i] = NULL;
 309}
 310
 311/**
 312 * cpuidle_add_driver_sysfs - adds driver-specific sysfs attributes
 313 * @device: the target device
 314 */
 315int cpuidle_add_state_sysfs(struct cpuidle_device *device)
 316{
 317        int i, ret = -ENOMEM;
 318        struct cpuidle_state_kobj *kobj;
 319
 320        /* state statistics */
 321        for (i = 0; i < device->state_count; i++) {
 322                kobj = kzalloc(sizeof(struct cpuidle_state_kobj), GFP_KERNEL);
 323                if (!kobj)
 324                        goto error_state;
 325                kobj->state = &device->states[i];
 326                init_completion(&kobj->kobj_unregister);
 327
 328                ret = kobject_init_and_add(&kobj->kobj, &ktype_state_cpuidle, &device->kobj,
 329                                           "state%d", i);
 330                if (ret) {
 331                        kfree(kobj);
 332                        goto error_state;
 333                }
 334                kobject_uevent(&kobj->kobj, KOBJ_ADD);
 335                device->kobjs[i] = kobj;
 336        }
 337
 338        return 0;
 339
 340error_state:
 341        for (i = i - 1; i >= 0; i--)
 342                cpuidle_free_state_kobj(device, i);
 343        return ret;
 344}
 345
 346/**
 347 * cpuidle_remove_driver_sysfs - removes driver-specific sysfs attributes
 348 * @device: the target device
 349 */
 350void cpuidle_remove_state_sysfs(struct cpuidle_device *device)
 351{
 352        int i;
 353
 354        for (i = 0; i < device->state_count; i++)
 355                cpuidle_free_state_kobj(device, i);
 356}
 357
 358/**
 359 * cpuidle_add_sysfs - creates a sysfs instance for the target device
 360 * @sysdev: the target device
 361 */
 362int cpuidle_add_sysfs(struct sys_device *sysdev)
 363{
 364        int cpu = sysdev->id;
 365        struct cpuidle_device *dev;
 366        int error;
 367
 368        dev = per_cpu(cpuidle_devices, cpu);
 369        error = kobject_init_and_add(&dev->kobj, &ktype_cpuidle, &sysdev->kobj,
 370                                     "cpuidle");
 371        if (!error)
 372                kobject_uevent(&dev->kobj, KOBJ_ADD);
 373        return error;
 374}
 375
 376/**
 377 * cpuidle_remove_sysfs - deletes a sysfs instance on the target device
 378 * @sysdev: the target device
 379 */
 380void cpuidle_remove_sysfs(struct sys_device *sysdev)
 381{
 382        int cpu = sysdev->id;
 383        struct cpuidle_device *dev;
 384
 385        dev = per_cpu(cpuidle_devices, cpu);
 386        kobject_put(&dev->kobj);
 387}
 388