drivers/macintosh/windfarm_core.c

   1 /*
   2  * Windfarm PowerMac thermal control. Core
   3  *
   4  * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
   5  *                    <benh@kernel.crashing.org>
   6  *
   7  * Released under the term of the GNU GPL v2.
   8  *
   9  * This core code tracks the list of sensors & controls, register
  10  * clients, and holds the kernel thread used for control.
  11  *
  12  * TODO:
  13  *
  14  * Add some information about sensor/control type and data format to
  15  * sensors/controls, and have the sysfs attribute stuff be moved
  16  * generically here instead of hard coded in the platform specific
  17  * driver as it us currently
  18  *
  19  * This however requires solving some annoying lifetime issues with
  20  * sysfs which doesn't seem to have lifetime rules for struct attribute,
  21  * I may have to create full features kobjects for every sensor/control
  22  * instead which is a bit of an overkill imho
  23  */
  24
  25 #include <linux/types.h>
  26 #include <linux/errno.h>
  27 #include <linux/kernel.h>
  28 #include <linux/slab.h>
  29 #include <linux/init.h>
  30 #include <linux/spinlock.h>
  31 #include <linux/kthread.h>
  32 #include <linux/jiffies.h>
  33 #include <linux/reboot.h>
  34 #include <linux/device.h>
  35 #include <linux/platform_device.h>
  36 #include <linux/mutex.h>
  37 #include <linux/freezer.h>
  38
  39 #include <asm/prom.h>
  40
  41 #include "windfarm.h"
  42
  43 #define VERSION "0.2"
  44
  45 #undef DEBUG
  46
  47 #ifdef DEBUG
  48 #define DBG(args...)    printk(args)
  49 #else
  50 #define DBG(args...)    do { } while(0)
  51 #endif
  52
  53 static LIST_HEAD(wf_controls);
  54 static LIST_HEAD(wf_sensors);
  55 static DEFINE_MUTEX(wf_lock);
  56 static BLOCKING_NOTIFIER_HEAD(wf_client_list);
  57 static int wf_client_count;
  58 static unsigned int wf_overtemp;
  59 static unsigned int wf_overtemp_counter;
  60 struct task_struct *wf_thread;
  61
  62 static struct platform_device wf_platform_device = {
  63         .name   = "windfarm",
  64 };
  65
  66 /*
  67  * Utilities & tick thread
  68  */
  69
  70 static inline void wf_notify(int event, void *param)
  71 {
  72         blocking_notifier_call_chain(&wf_client_list, event, param);
  73 }
  74
  75 int wf_critical_overtemp(void)
  76 {
  77         static char * critical_overtemp_path = "/sbin/critical_overtemp";
  78         char *argv[] = { critical_overtemp_path, NULL };
  79         static char *envp[] = { "HOME=/",
  80                                 "TERM=linux",
  81                                 "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
  82                                 NULL };
  83
  84         return call_usermodehelper(critical_overtemp_path,
  85                                    argv, envp, UMH_WAIT_EXEC);
  86 }
  87 EXPORT_SYMBOL_GPL(wf_critical_overtemp);
  88
  89 static int wf_thread_func(void *data)
  90 {
  91         unsigned long next, delay;
  92
  93         next = jiffies;
  94
  95         DBG("wf: thread started\n");
  96
  97         set_freezable();
  98         while (!kthread_should_stop()) {
  99                 try_to_freeze();
 100
 101                 if (time_after_eq(jiffies, next)) {
 102                         wf_notify(WF_EVENT_TICK, NULL);
 103                         if (wf_overtemp) {
 104                                 wf_overtemp_counter++;
 105                                 /* 10 seconds overtemp, notify userland */
 106                                 if (wf_overtemp_counter > 10)
 107                                         wf_critical_overtemp();
 108                                 /* 30 seconds, shutdown */
 109                                 if (wf_overtemp_counter > 30) {
 110                                         printk(KERN_ERR "windfarm: Overtemp "
 111                                                "for more than 30"
 112                                                " seconds, shutting down\n");
 113                                         machine_power_off();
 114                                 }
 115                         }
 116                         next += HZ;
 117                 }
 118
 119                 delay = next - jiffies;
 120                 if (delay <= HZ)
 121                         schedule_timeout_interruptible(delay);
 122         }
 123
 124         DBG("wf: thread stopped\n");
 125
 126         return 0;
 127 }
 128
 129 static void wf_start_thread(void)
 130 {
 131         wf_thread = kthread_run(wf_thread_func, NULL, "kwindfarm");
 132         if (IS_ERR(wf_thread)) {
 133                 printk(KERN_ERR "windfarm: failed to create thread,err %ld\n",
 134                        PTR_ERR(wf_thread));
 135                 wf_thread = NULL;
 136         }
 137 }
 138
 139
 140 static void wf_stop_thread(void)
 141 {
 142         if (wf_thread)
 143                 kthread_stop(wf_thread);
 144         wf_thread = NULL;
 145 }
 146
 147 /*
 148  * Controls
 149  */
 150
 151 static void wf_control_release(struct kref *kref)
 152 {
 153         struct wf_control *ct = container_of(kref, struct wf_control, ref);
 154
 155         DBG("wf: Deleting control %s\n", ct->name);
 156
 157         if (ct->ops && ct->ops->release)
 158                 ct->ops->release(ct);
 159         else
 160                 kfree(ct);
 161 }
 162
 163 static ssize_t wf_show_control(struct device *dev,
 164                                struct device_attribute *attr, char *buf)
 165 {
 166         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
 167         const char *typestr;
 168         s32 val = 0;
 169         int err;
 170
 171         err = ctrl->ops->get_value(ctrl, &val);
 172         if (err < 0) {
 173                 if (err == -EFAULT)
 174                         return sprintf(buf, "<HW FAULT>\n");
 175                 return err;
 176         }
 177         switch(ctrl->type) {
 178         case WF_CONTROL_RPM_FAN:
 179                 typestr = " RPM";
 180                 break;
 181         case WF_CONTROL_PWM_FAN:
 182                 typestr = " %";
 183                 break;
 184         default:
 185                 typestr = "";
 186         }
 187         return sprintf(buf, "%d%s\n", val, typestr);
 188 }
 189
 190 /* This is really only for debugging... */
 191 static ssize_t wf_store_control(struct device *dev,
 192                                 struct device_attribute *attr,
 193                                 const char *buf, size_t count)
 194 {
 195         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
 196         int val;
 197         int err;
 198         char *endp;
 199
 200         val = simple_strtoul(buf, &endp, 0);
 201         while (endp < buf + count && (*endp == ' ' || *endp == '\n'))
 202                 ++endp;
 203         if (endp - buf < count)
 204                 return -EINVAL;
 205         err = ctrl->ops->set_value(ctrl, val);
 206         if (err < 0)
 207                 return err;
 208         return count;
 209 }
 210
 211 int wf_register_control(struct wf_control *new_ct)
 212 {
 213         struct wf_control *ct;
 214
 215         mutex_lock(&wf_lock);
 216         list_for_each_entry(ct, &wf_controls, link) {
 217                 if (!strcmp(ct->name, new_ct->name)) {
 218                         printk(KERN_WARNING "windfarm: trying to register"
 219                                " duplicate control %s\n", ct->name);
 220                         mutex_unlock(&wf_lock);
 221                         return -EEXIST;
 222                 }
 223         }
 224         kref_init(&new_ct->ref);
 225         list_add(&new_ct->link, &wf_controls);
 226
 227         sysfs_attr_init(&new_ct->attr.attr);
 228         new_ct->attr.attr.name = new_ct->name;
 229         new_ct->attr.attr.mode = 0644;
 230         new_ct->attr.show = wf_show_control;
 231         new_ct->attr.store = wf_store_control;
 232         if (device_create_file(&wf_platform_device.dev, &new_ct->attr))
 233                 printk(KERN_WARNING "windfarm: device_create_file failed"
 234                         " for %s\n", new_ct->name);
 235                 /* the subsystem still does useful work without the file */
 236
 237         DBG("wf: Registered control %s\n", new_ct->name);
 238
 239         wf_notify(WF_EVENT_NEW_CONTROL, new_ct);
 240         mutex_unlock(&wf_lock);
 241
 242         return 0;
 243 }
 244 EXPORT_SYMBOL_GPL(wf_register_control);
 245
 246 void wf_unregister_control(struct wf_control *ct)
 247 {
 248         mutex_lock(&wf_lock);
 249         list_del(&ct->link);
 250         mutex_unlock(&wf_lock);
 251
 252         DBG("wf: Unregistered control %s\n", ct->name);
 253
 254         kref_put(&ct->ref, wf_control_release);
 255 }
 256 EXPORT_SYMBOL_GPL(wf_unregister_control);
 257
 258 struct wf_control * wf_find_control(const char *name)
 259 {
 260         struct wf_control *ct;
 261
 262         mutex_lock(&wf_lock);
 263         list_for_each_entry(ct, &wf_controls, link) {
 264                 if (!strcmp(ct->name, name)) {
 265                         if (wf_get_control(ct))
 266                                 ct = NULL;
 267                         mutex_unlock(&wf_lock);
 268                         return ct;
 269                 }
 270         }
 271         mutex_unlock(&wf_lock);
 272         return NULL;
 273 }
 274 EXPORT_SYMBOL_GPL(wf_find_control);
 275
 276 int wf_get_control(struct wf_control *ct)
 277 {
 278         if (!try_module_get(ct->ops->owner))
 279                 return -ENODEV;
 280         kref_get(&ct->ref);
 281         return 0;
 282 }
 283 EXPORT_SYMBOL_GPL(wf_get_control);
 284
 285 void wf_put_control(struct wf_control *ct)
 286 {
 287         struct module *mod = ct->ops->owner;
 288         kref_put(&ct->ref, wf_control_release);
 289         module_put(mod);
 290 }
 291 EXPORT_SYMBOL_GPL(wf_put_control);
 292
 293
 294 /*
 295  * Sensors
 296  */
 297
 298
 299 static void wf_sensor_release(struct kref *kref)
 300 {
 301         struct wf_sensor *sr = container_of(kref, struct wf_sensor, ref);
 302
 303         DBG("wf: Deleting sensor %s\n", sr->name);
 304
 305         if (sr->ops && sr->ops->release)
 306                 sr->ops->release(sr);
 307         else
 308                 kfree(sr);
 309 }
 310
 311 static ssize_t wf_show_sensor(struct device *dev,
 312                               struct device_attribute *attr, char *buf)
 313 {
 314         struct wf_sensor *sens = container_of(attr, struct wf_sensor, attr);
 315         s32 val = 0;
 316         int err;
 317
 318         err = sens->ops->get_value(sens, &val);
 319         if (err < 0)
 320                 return err;
 321         return sprintf(buf, "%d.%03d\n", FIX32TOPRINT(val));
 322 }
 323
 324 int wf_register_sensor(struct wf_sensor *new_sr)
 325 {
 326         struct wf_sensor *sr;
 327
 328         mutex_lock(&wf_lock);
 329         list_for_each_entry(sr, &wf_sensors, link) {
 330                 if (!strcmp(sr->name, new_sr->name)) {
 331                         printk(KERN_WARNING "windfarm: trying to register"
 332                                " duplicate sensor %s\n", sr->name);
 333                         mutex_unlock(&wf_lock);
 334                         return -EEXIST;
 335                 }
 336         }
 337         kref_init(&new_sr->ref);
 338         list_add(&new_sr->link, &wf_sensors);
 339
 340         sysfs_attr_init(&new_sr->attr.attr);
 341         new_sr->attr.attr.name = new_sr->name;
 342         new_sr->attr.attr.mode = 0444;
 343         new_sr->attr.show = wf_show_sensor;
 344         new_sr->attr.store = NULL;
 345         if (device_create_file(&wf_platform_device.dev, &new_sr->attr))
 346                 printk(KERN_WARNING "windfarm: device_create_file failed"
 347                         " for %s\n", new_sr->name);
 348                 /* the subsystem still does useful work without the file */
 349
 350         DBG("wf: Registered sensor %s\n", new_sr->name);
 351
 352         wf_notify(WF_EVENT_NEW_SENSOR, new_sr);
 353         mutex_unlock(&wf_lock);
 354
 355         return 0;
 356 }
 357 EXPORT_SYMBOL_GPL(wf_register_sensor);
 358
 359 void wf_unregister_sensor(struct wf_sensor *sr)
 360 {
 361         mutex_lock(&wf_lock);
 362         list_del(&sr->link);
 363         mutex_unlock(&wf_lock);
 364
 365         DBG("wf: Unregistered sensor %s\n", sr->name);
 366
 367         wf_put_sensor(sr);
 368 }
 369 EXPORT_SYMBOL_GPL(wf_unregister_sensor);
 370
 371 struct wf_sensor * wf_find_sensor(const char *name)
 372 {
 373         struct wf_sensor *sr;
 374
 375         mutex_lock(&wf_lock);
 376         list_for_each_entry(sr, &wf_sensors, link) {
 377                 if (!strcmp(sr->name, name)) {
 378                         if (wf_get_sensor(sr))
 379                                 sr = NULL;
 380                         mutex_unlock(&wf_lock);
 381                         return sr;
 382                 }
 383         }
 384         mutex_unlock(&wf_lock);
 385         return NULL;
 386 }
 387 EXPORT_SYMBOL_GPL(wf_find_sensor);
 388
 389 int wf_get_sensor(struct wf_sensor *sr)
 390 {
 391         if (!try_module_get(sr->ops->owner))
 392                 return -ENODEV;
 393         kref_get(&sr->ref);
 394         return 0;
 395 }
 396 EXPORT_SYMBOL_GPL(wf_get_sensor);
 397
 398 void wf_put_sensor(struct wf_sensor *sr)
 399 {
 400         struct module *mod = sr->ops->owner;
 401         kref_put(&sr->ref, wf_sensor_release);
 402         module_put(mod);
 403 }
 404 EXPORT_SYMBOL_GPL(wf_put_sensor);
 405
 406
 407 /*
 408  * Client & notification
 409  */
 410
 411 int wf_register_client(struct notifier_block *nb)
 412 {
 413         int rc;
 414         struct wf_control *ct;
 415         struct wf_sensor *sr;
 416
 417         mutex_lock(&wf_lock);
 418         rc = blocking_notifier_chain_register(&wf_client_list, nb);
 419         if (rc != 0)
 420                 goto bail;
 421         wf_client_count++;
 422         list_for_each_entry(ct, &wf_controls, link)
 423                 wf_notify(WF_EVENT_NEW_CONTROL, ct);
 424         list_for_each_entry(sr, &wf_sensors, link)
 425                 wf_notify(WF_EVENT_NEW_SENSOR, sr);
 426         if (wf_client_count == 1)
 427                 wf_start_thread();
 428  bail:
 429         mutex_unlock(&wf_lock);
 430         return rc;
 431 }
 432 EXPORT_SYMBOL_GPL(wf_register_client);
 433
 434 int wf_unregister_client(struct notifier_block *nb)
 435 {
 436         mutex_lock(&wf_lock);
 437         blocking_notifier_chain_unregister(&wf_client_list, nb);
 438         wf_client_count++;
 439         if (wf_client_count == 0)
 440                 wf_stop_thread();
 441         mutex_unlock(&wf_lock);
 442
 443         return 0;
 444 }
 445 EXPORT_SYMBOL_GPL(wf_unregister_client);
 446
 447 void wf_set_overtemp(void)
 448 {
 449         mutex_lock(&wf_lock);
 450         wf_overtemp++;
 451         if (wf_overtemp == 1) {
 452                 printk(KERN_WARNING "windfarm: Overtemp condition detected !\n");
 453                 wf_overtemp_counter = 0;
 454                 wf_notify(WF_EVENT_OVERTEMP, NULL);
 455         }
 456         mutex_unlock(&wf_lock);
 457 }
 458 EXPORT_SYMBOL_GPL(wf_set_overtemp);
 459
 460 void wf_clear_overtemp(void)
 461 {
 462         mutex_lock(&wf_lock);
 463         WARN_ON(wf_overtemp == 0);
 464         if (wf_overtemp == 0) {
 465                 mutex_unlock(&wf_lock);
 466                 return;
 467         }
 468         wf_overtemp--;
 469         if (wf_overtemp == 0) {
 470                 printk(KERN_WARNING "windfarm: Overtemp condition cleared !\n");
 471                 wf_notify(WF_EVENT_NORMALTEMP, NULL);
 472         }
 473         mutex_unlock(&wf_lock);
 474 }
 475 EXPORT_SYMBOL_GPL(wf_clear_overtemp);
 476
 477 int wf_is_overtemp(void)
 478 {
 479         return (wf_overtemp != 0);
 480 }
 481 EXPORT_SYMBOL_GPL(wf_is_overtemp);
 482
 483 static int __init windfarm_core_init(void)
 484 {
 485         DBG("wf: core loaded\n");
 486
 487         platform_device_register(&wf_platform_device);
 488         return 0;
 489 }
 490
 491 static void __exit windfarm_core_exit(void)
 492 {
 493         BUG_ON(wf_client_count != 0);
 494
 495         DBG("wf: core unloaded\n");
 496
 497         platform_device_unregister(&wf_platform_device);
 498 }
 499
 500
 501 module_init(windfarm_core_init);
 502 module_exit(windfarm_core_exit);
 503
 504 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 505 MODULE_DESCRIPTION("Core component of PowerMac thermal control");
 506 MODULE_LICENSE("GPL");
 507