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/init.h>
  29 #include <linux/spinlock.h>
  30 #include <linux/smp_lock.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, argv, envp, 0);
  85 }
  86 EXPORT_SYMBOL_GPL(wf_critical_overtemp);
  87
  88 static int wf_thread_func(void *data)
  89 {
  90         unsigned long next, delay;
  91
  92         next = jiffies;
  93
  94         DBG("wf: thread started\n");
  95
  96         while(!kthread_should_stop()) {
  97                 if (time_after_eq(jiffies, next)) {
  98                         wf_notify(WF_EVENT_TICK, NULL);
  99                         if (wf_overtemp) {
 100                                 wf_overtemp_counter++;
 101                                 /* 10 seconds overtemp, notify userland */
 102                                 if (wf_overtemp_counter > 10)
 103                                         wf_critical_overtemp();
 104                                 /* 30 seconds, shutdown */
 105                                 if (wf_overtemp_counter > 30) {
 106                                         printk(KERN_ERR "windfarm: Overtemp "
 107                                                "for more than 30"
 108                                                " seconds, shutting down\n");
 109                                         machine_power_off();
 110                                 }
 111                         }
 112                         next += HZ;
 113                 }
 114
 115                 delay = next - jiffies;
 116                 if (delay <= HZ)
 117                         schedule_timeout_interruptible(delay);
 118
 119                 /* there should be no non-suspend signal, but oh well */
 120                 if (signal_pending(current) && !try_to_freeze()) {
 121                         printk(KERN_WARNING "windfarm: thread got sigl !\n");
 122                         break;
 123                 }
 124         }
 125
 126         DBG("wf: thread stopped\n");
 127
 128         return 0;
 129 }
 130
 131 static void wf_start_thread(void)
 132 {
 133         wf_thread = kthread_run(wf_thread_func, NULL, "kwindfarm");
 134         if (IS_ERR(wf_thread)) {
 135                 printk(KERN_ERR "windfarm: failed to create thread,err %ld\n",
 136                        PTR_ERR(wf_thread));
 137                 wf_thread = NULL;
 138         }
 139 }
 140
 141
 142 static void wf_stop_thread(void)
 143 {
 144         if (wf_thread)
 145                 kthread_stop(wf_thread);
 146         wf_thread = NULL;
 147 }
 148
 149 /*
 150  * Controls
 151  */
 152
 153 static void wf_control_release(struct kref *kref)
 154 {
 155         struct wf_control *ct = container_of(kref, struct wf_control, ref);
 156
 157         DBG("wf: Deleting control %s\n", ct->name);
 158
 159         if (ct->ops && ct->ops->release)
 160                 ct->ops->release(ct);
 161         else
 162                 kfree(ct);
 163 }
 164
 165 static ssize_t wf_show_control(struct device *dev,
 166                                struct device_attribute *attr, char *buf)
 167 {
 168         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
 169         s32 val = 0;
 170         int err;
 171
 172         err = ctrl->ops->get_value(ctrl, &val);
 173         if (err < 0)
 174                 return err;
 175         return sprintf(buf, "%d\n", val);
 176 }
 177
 178 /* This is really only for debugging... */
 179 static ssize_t wf_store_control(struct device *dev,
 180                                 struct device_attribute *attr,
 181                                 const char *buf, size_t count)
 182 {
 183         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
 184         int val;
 185         int err;
 186         char *endp;
 187
 188         val = simple_strtoul(buf, &endp, 0);
 189         while (endp < buf + count && (*endp == ' ' || *endp == '\n'))
 190                 ++endp;
 191         if (endp - buf < count)
 192                 return -EINVAL;
 193         err = ctrl->ops->set_value(ctrl, val);
 194         if (err < 0)
 195                 return err;
 196         return count;
 197 }
 198
 199 int wf_register_control(struct wf_control *new_ct)
 200 {
 201         struct wf_control *ct;
 202
 203         mutex_lock(&wf_lock);
 204         list_for_each_entry(ct, &wf_controls, link) {
 205                 if (!strcmp(ct->name, new_ct->name)) {
 206                         printk(KERN_WARNING "windfarm: trying to register"
 207                                " duplicate control %s\n", ct->name);
 208                         mutex_unlock(&wf_lock);
 209                         return -EEXIST;
 210                 }
 211         }
 212         kref_init(&new_ct->ref);
 213         list_add(&new_ct->link, &wf_controls);
 214
 215         new_ct->attr.attr.name = new_ct->name;
 216         new_ct->attr.attr.owner = THIS_MODULE;
 217         new_ct->attr.attr.mode = 0644;
 218         new_ct->attr.show = wf_show_control;
 219         new_ct->attr.store = wf_store_control;
 220         device_create_file(&wf_platform_device.dev, &new_ct->attr);
 221
 222         DBG("wf: Registered control %s\n", new_ct->name);
 223
 224         wf_notify(WF_EVENT_NEW_CONTROL, new_ct);
 225         mutex_unlock(&wf_lock);
 226
 227         return 0;
 228 }
 229 EXPORT_SYMBOL_GPL(wf_register_control);
 230
 231 void wf_unregister_control(struct wf_control *ct)
 232 {
 233         mutex_lock(&wf_lock);
 234         list_del(&ct->link);
 235         mutex_unlock(&wf_lock);
 236
 237         DBG("wf: Unregistered control %s\n", ct->name);
 238
 239         kref_put(&ct->ref, wf_control_release);
 240 }
 241 EXPORT_SYMBOL_GPL(wf_unregister_control);
 242
 243 struct wf_control * wf_find_control(const char *name)
 244 {
 245         struct wf_control *ct;
 246
 247         mutex_lock(&wf_lock);
 248         list_for_each_entry(ct, &wf_controls, link) {
 249                 if (!strcmp(ct->name, name)) {
 250                         if (wf_get_control(ct))
 251                                 ct = NULL;
 252                         mutex_unlock(&wf_lock);
 253                         return ct;
 254                 }
 255         }
 256         mutex_unlock(&wf_lock);
 257         return NULL;
 258 }
 259 EXPORT_SYMBOL_GPL(wf_find_control);
 260
 261 int wf_get_control(struct wf_control *ct)
 262 {
 263         if (!try_module_get(ct->ops->owner))
 264                 return -ENODEV;
 265         kref_get(&ct->ref);
 266         return 0;
 267 }
 268 EXPORT_SYMBOL_GPL(wf_get_control);
 269
 270 void wf_put_control(struct wf_control *ct)
 271 {
 272         struct module *mod = ct->ops->owner;
 273         kref_put(&ct->ref, wf_control_release);
 274         module_put(mod);
 275 }
 276 EXPORT_SYMBOL_GPL(wf_put_control);
 277
 278
 279 /*
 280  * Sensors
 281  */
 282
 283
 284 static void wf_sensor_release(struct kref *kref)
 285 {
 286         struct wf_sensor *sr = container_of(kref, struct wf_sensor, ref);
 287
 288         DBG("wf: Deleting sensor %s\n", sr->name);
 289
 290         if (sr->ops && sr->ops->release)
 291                 sr->ops->release(sr);
 292         else
 293                 kfree(sr);
 294 }
 295
 296 static ssize_t wf_show_sensor(struct device *dev,
 297                               struct device_attribute *attr, char *buf)
 298 {
 299         struct wf_sensor *sens = container_of(attr, struct wf_sensor, attr);
 300         s32 val = 0;
 301         int err;
 302
 303         err = sens->ops->get_value(sens, &val);
 304         if (err < 0)
 305                 return err;
 306         return sprintf(buf, "%d.%03d\n", FIX32TOPRINT(val));
 307 }
 308
 309 int wf_register_sensor(struct wf_sensor *new_sr)
 310 {
 311         struct wf_sensor *sr;
 312
 313         mutex_lock(&wf_lock);
 314         list_for_each_entry(sr, &wf_sensors, link) {
 315                 if (!strcmp(sr->name, new_sr->name)) {
 316                         printk(KERN_WARNING "windfarm: trying to register"
 317                                " duplicate sensor %s\n", sr->name);
 318                         mutex_unlock(&wf_lock);
 319                         return -EEXIST;
 320                 }
 321         }
 322         kref_init(&new_sr->ref);
 323         list_add(&new_sr->link, &wf_sensors);
 324
 325         new_sr->attr.attr.name = new_sr->name;
 326         new_sr->attr.attr.owner = THIS_MODULE;
 327         new_sr->attr.attr.mode = 0444;
 328         new_sr->attr.show = wf_show_sensor;
 329         new_sr->attr.store = NULL;
 330         device_create_file(&wf_platform_device.dev, &new_sr->attr);
 331
 332         DBG("wf: Registered sensor %s\n", new_sr->name);
 333
 334         wf_notify(WF_EVENT_NEW_SENSOR, new_sr);
 335         mutex_unlock(&wf_lock);
 336
 337         return 0;
 338 }
 339 EXPORT_SYMBOL_GPL(wf_register_sensor);
 340
 341 void wf_unregister_sensor(struct wf_sensor *sr)
 342 {
 343         mutex_lock(&wf_lock);
 344         list_del(&sr->link);
 345         mutex_unlock(&wf_lock);
 346
 347         DBG("wf: Unregistered sensor %s\n", sr->name);
 348
 349         wf_put_sensor(sr);
 350 }
 351 EXPORT_SYMBOL_GPL(wf_unregister_sensor);
 352
 353 struct wf_sensor * wf_find_sensor(const char *name)
 354 {
 355         struct wf_sensor *sr;
 356
 357         mutex_lock(&wf_lock);
 358         list_for_each_entry(sr, &wf_sensors, link) {
 359                 if (!strcmp(sr->name, name)) {
 360                         if (wf_get_sensor(sr))
 361                                 sr = NULL;
 362                         mutex_unlock(&wf_lock);
 363                         return sr;
 364                 }
 365         }
 366         mutex_unlock(&wf_lock);
 367         return NULL;
 368 }
 369 EXPORT_SYMBOL_GPL(wf_find_sensor);
 370
 371 int wf_get_sensor(struct wf_sensor *sr)
 372 {
 373         if (!try_module_get(sr->ops->owner))
 374                 return -ENODEV;
 375         kref_get(&sr->ref);
 376         return 0;
 377 }
 378 EXPORT_SYMBOL_GPL(wf_get_sensor);
 379
 380 void wf_put_sensor(struct wf_sensor *sr)
 381 {
 382         struct module *mod = sr->ops->owner;
 383         kref_put(&sr->ref, wf_sensor_release);
 384         module_put(mod);
 385 }
 386 EXPORT_SYMBOL_GPL(wf_put_sensor);
 387
 388
 389 /*
 390  * Client & notification
 391  */
 392
 393 int wf_register_client(struct notifier_block *nb)
 394 {
 395         int rc;
 396         struct wf_control *ct;
 397         struct wf_sensor *sr;
 398
 399         mutex_lock(&wf_lock);
 400         rc = blocking_notifier_chain_register(&wf_client_list, nb);
 401         if (rc != 0)
 402                 goto bail;
 403         wf_client_count++;
 404         list_for_each_entry(ct, &wf_controls, link)
 405                 wf_notify(WF_EVENT_NEW_CONTROL, ct);
 406         list_for_each_entry(sr, &wf_sensors, link)
 407                 wf_notify(WF_EVENT_NEW_SENSOR, sr);
 408         if (wf_client_count == 1)
 409                 wf_start_thread();
 410  bail:
 411         mutex_unlock(&wf_lock);
 412         return rc;
 413 }
 414 EXPORT_SYMBOL_GPL(wf_register_client);
 415
 416 int wf_unregister_client(struct notifier_block *nb)
 417 {
 418         mutex_lock(&wf_lock);
 419         blocking_notifier_chain_unregister(&wf_client_list, nb);
 420         wf_client_count++;
 421         if (wf_client_count == 0)
 422                 wf_stop_thread();
 423         mutex_unlock(&wf_lock);
 424
 425         return 0;
 426 }
 427 EXPORT_SYMBOL_GPL(wf_unregister_client);
 428
 429 void wf_set_overtemp(void)
 430 {
 431         mutex_lock(&wf_lock);
 432         wf_overtemp++;
 433         if (wf_overtemp == 1) {
 434                 printk(KERN_WARNING "windfarm: Overtemp condition detected !\n");
 435                 wf_overtemp_counter = 0;
 436                 wf_notify(WF_EVENT_OVERTEMP, NULL);
 437         }
 438         mutex_unlock(&wf_lock);
 439 }
 440 EXPORT_SYMBOL_GPL(wf_set_overtemp);
 441
 442 void wf_clear_overtemp(void)
 443 {
 444         mutex_lock(&wf_lock);
 445         WARN_ON(wf_overtemp == 0);
 446         if (wf_overtemp == 0) {
 447                 mutex_unlock(&wf_lock);
 448                 return;
 449         }
 450         wf_overtemp--;
 451         if (wf_overtemp == 0) {
 452                 printk(KERN_WARNING "windfarm: Overtemp condition cleared !\n");
 453                 wf_notify(WF_EVENT_NORMALTEMP, NULL);
 454         }
 455         mutex_unlock(&wf_lock);
 456 }
 457 EXPORT_SYMBOL_GPL(wf_clear_overtemp);
 458
 459 int wf_is_overtemp(void)
 460 {
 461         return (wf_overtemp != 0);
 462 }
 463 EXPORT_SYMBOL_GPL(wf_is_overtemp);
 464
 465 static int __init windfarm_core_init(void)
 466 {
 467         DBG("wf: core loaded\n");
 468
 469         /* Don't register on old machines that use therm_pm72 for now */
 470         if (machine_is_compatible("PowerMac7,2") ||
 471             machine_is_compatible("PowerMac7,3") ||
 472             machine_is_compatible("RackMac3,1"))
 473                 return -ENODEV;
 474         platform_device_register(&wf_platform_device);
 475         return 0;
 476 }
 477
 478 static void __exit windfarm_core_exit(void)
 479 {
 480         BUG_ON(wf_client_count != 0);
 481
 482         DBG("wf: core unloaded\n");
 483
 484         platform_device_unregister(&wf_platform_device);
 485 }
 486
 487
 488 module_init(windfarm_core_init);
 489 module_exit(windfarm_core_exit);
 490
 491 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 492 MODULE_DESCRIPTION("Core component of PowerMac thermal control");
 493 MODULE_LICENSE("GPL");
 494