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                 try_to_freeze();
  98
  99                 if (time_after_eq(jiffies, next)) {
 100                         wf_notify(WF_EVENT_TICK, NULL);
 101                         if (wf_overtemp) {
 102                                 wf_overtemp_counter++;
 103                                 /* 10 seconds overtemp, notify userland */
 104                                 if (wf_overtemp_counter > 10)
 105                                         wf_critical_overtemp();
 106                                 /* 30 seconds, shutdown */
 107                                 if (wf_overtemp_counter > 30) {
 108                                         printk(KERN_ERR "windfarm: Overtemp "
 109                                                "for more than 30"
 110                                                " seconds, shutting down\n");
 111                                         machine_power_off();
 112                                 }
 113                         }
 114                         next += HZ;
 115                 }
 116
 117                 delay = next - jiffies;
 118                 if (delay <= HZ)
 119                         schedule_timeout_interruptible(delay);
 120
 121                 /* there should be no signal, but oh well */
 122                 if (signal_pending(current)) {
 123                         printk(KERN_WARNING "windfarm: thread got sigl !\n");
 124                         break;
 125                 }
 126         }
 127
 128         DBG("wf: thread stopped\n");
 129
 130         return 0;
 131 }
 132
 133 static void wf_start_thread(void)
 134 {
 135         wf_thread = kthread_run(wf_thread_func, NULL, "kwindfarm");
 136         if (IS_ERR(wf_thread)) {
 137                 printk(KERN_ERR "windfarm: failed to create thread,err %ld\n",
 138                        PTR_ERR(wf_thread));
 139                 wf_thread = NULL;
 140         }
 141 }
 142
 143
 144 static void wf_stop_thread(void)
 145 {
 146         if (wf_thread)
 147                 kthread_stop(wf_thread);
 148         wf_thread = NULL;
 149 }
 150
 151 /*
 152  * Controls
 153  */
 154
 155 static void wf_control_release(struct kref *kref)
 156 {
 157         struct wf_control *ct = container_of(kref, struct wf_control, ref);
 158
 159         DBG("wf: Deleting control %s\n", ct->name);
 160
 161         if (ct->ops && ct->ops->release)
 162                 ct->ops->release(ct);
 163         else
 164                 kfree(ct);
 165 }
 166
 167 static ssize_t wf_show_control(struct device *dev,
 168                                struct device_attribute *attr, char *buf)
 169 {
 170         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
 171         s32 val = 0;
 172         int err;
 173
 174         err = ctrl->ops->get_value(ctrl, &val);
 175         if (err < 0)
 176                 return err;
 177         return sprintf(buf, "%d\n", val);
 178 }
 179
 180 /* This is really only for debugging... */
 181 static ssize_t wf_store_control(struct device *dev,
 182                                 struct device_attribute *attr,
 183                                 const char *buf, size_t count)
 184 {
 185         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
 186         int val;
 187         int err;
 188         char *endp;
 189
 190         val = simple_strtoul(buf, &endp, 0);
 191         while (endp < buf + count && (*endp == ' ' || *endp == '\n'))
 192                 ++endp;
 193         if (endp - buf < count)
 194                 return -EINVAL;
 195         err = ctrl->ops->set_value(ctrl, val);
 196         if (err < 0)
 197                 return err;
 198         return count;
 199 }
 200
 201 int wf_register_control(struct wf_control *new_ct)
 202 {
 203         struct wf_control *ct;
 204
 205         mutex_lock(&wf_lock);
 206         list_for_each_entry(ct, &wf_controls, link) {
 207                 if (!strcmp(ct->name, new_ct->name)) {
 208                         printk(KERN_WARNING "windfarm: trying to register"
 209                                " duplicate control %s\n", ct->name);
 210                         mutex_unlock(&wf_lock);
 211                         return -EEXIST;
 212                 }
 213         }
 214         kref_init(&new_ct->ref);
 215         list_add(&new_ct->link, &wf_controls);
 216
 217         new_ct->attr.attr.name = new_ct->name;
 218         new_ct->attr.attr.owner = THIS_MODULE;
 219         new_ct->attr.attr.mode = 0644;
 220         new_ct->attr.show = wf_show_control;
 221         new_ct->attr.store = wf_store_control;
 222         device_create_file(&wf_platform_device.dev, &new_ct->attr);
 223
 224         DBG("wf: Registered control %s\n", new_ct->name);
 225
 226         wf_notify(WF_EVENT_NEW_CONTROL, new_ct);
 227         mutex_unlock(&wf_lock);
 228
 229         return 0;
 230 }
 231 EXPORT_SYMBOL_GPL(wf_register_control);
 232
 233 void wf_unregister_control(struct wf_control *ct)
 234 {
 235         mutex_lock(&wf_lock);
 236         list_del(&ct->link);
 237         mutex_unlock(&wf_lock);
 238
 239         DBG("wf: Unregistered control %s\n", ct->name);
 240
 241         kref_put(&ct->ref, wf_control_release);
 242 }
 243 EXPORT_SYMBOL_GPL(wf_unregister_control);
 244
 245 struct wf_control * wf_find_control(const char *name)
 246 {
 247         struct wf_control *ct;
 248
 249         mutex_lock(&wf_lock);
 250         list_for_each_entry(ct, &wf_controls, link) {
 251                 if (!strcmp(ct->name, name)) {
 252                         if (wf_get_control(ct))
 253                                 ct = NULL;
 254                         mutex_unlock(&wf_lock);
 255                         return ct;
 256                 }
 257         }
 258         mutex_unlock(&wf_lock);
 259         return NULL;
 260 }
 261 EXPORT_SYMBOL_GPL(wf_find_control);
 262
 263 int wf_get_control(struct wf_control *ct)
 264 {
 265         if (!try_module_get(ct->ops->owner))
 266                 return -ENODEV;
 267         kref_get(&ct->ref);
 268         return 0;
 269 }
 270 EXPORT_SYMBOL_GPL(wf_get_control);
 271
 272 void wf_put_control(struct wf_control *ct)
 273 {
 274         struct module *mod = ct->ops->owner;
 275         kref_put(&ct->ref, wf_control_release);
 276         module_put(mod);
 277 }
 278 EXPORT_SYMBOL_GPL(wf_put_control);
 279
 280
 281 /*
 282  * Sensors
 283  */
 284
 285
 286 static void wf_sensor_release(struct kref *kref)
 287 {
 288         struct wf_sensor *sr = container_of(kref, struct wf_sensor, ref);
 289
 290         DBG("wf: Deleting sensor %s\n", sr->name);
 291
 292         if (sr->ops && sr->ops->release)
 293                 sr->ops->release(sr);
 294         else
 295                 kfree(sr);
 296 }
 297
 298 static ssize_t wf_show_sensor(struct device *dev,
 299                               struct device_attribute *attr, char *buf)
 300 {
 301         struct wf_sensor *sens = container_of(attr, struct wf_sensor, attr);
 302         s32 val = 0;
 303         int err;
 304
 305         err = sens->ops->get_value(sens, &val);
 306         if (err < 0)
 307                 return err;
 308         return sprintf(buf, "%d.%03d\n", FIX32TOPRINT(val));
 309 }
 310
 311 int wf_register_sensor(struct wf_sensor *new_sr)
 312 {
 313         struct wf_sensor *sr;
 314
 315         mutex_lock(&wf_lock);
 316         list_for_each_entry(sr, &wf_sensors, link) {
 317                 if (!strcmp(sr->name, new_sr->name)) {
 318                         printk(KERN_WARNING "windfarm: trying to register"
 319                                " duplicate sensor %s\n", sr->name);
 320                         mutex_unlock(&wf_lock);
 321                         return -EEXIST;
 322                 }
 323         }
 324         kref_init(&new_sr->ref);
 325         list_add(&new_sr->link, &wf_sensors);
 326
 327         new_sr->attr.attr.name = new_sr->name;
 328         new_sr->attr.attr.owner = THIS_MODULE;
 329         new_sr->attr.attr.mode = 0444;
 330         new_sr->attr.show = wf_show_sensor;
 331         new_sr->attr.store = NULL;
 332         device_create_file(&wf_platform_device.dev, &new_sr->attr);
 333
 334         DBG("wf: Registered sensor %s\n", new_sr->name);
 335
 336         wf_notify(WF_EVENT_NEW_SENSOR, new_sr);
 337         mutex_unlock(&wf_lock);
 338
 339         return 0;
 340 }
 341 EXPORT_SYMBOL_GPL(wf_register_sensor);
 342
 343 void wf_unregister_sensor(struct wf_sensor *sr)
 344 {
 345         mutex_lock(&wf_lock);
 346         list_del(&sr->link);
 347         mutex_unlock(&wf_lock);
 348
 349         DBG("wf: Unregistered sensor %s\n", sr->name);
 350
 351         wf_put_sensor(sr);
 352 }
 353 EXPORT_SYMBOL_GPL(wf_unregister_sensor);
 354
 355 struct wf_sensor * wf_find_sensor(const char *name)
 356 {
 357         struct wf_sensor *sr;
 358
 359         mutex_lock(&wf_lock);
 360         list_for_each_entry(sr, &wf_sensors, link) {
 361                 if (!strcmp(sr->name, name)) {
 362                         if (wf_get_sensor(sr))
 363                                 sr = NULL;
 364                         mutex_unlock(&wf_lock);
 365                         return sr;
 366                 }
 367         }
 368         mutex_unlock(&wf_lock);
 369         return NULL;
 370 }
 371 EXPORT_SYMBOL_GPL(wf_find_sensor);
 372
 373 int wf_get_sensor(struct wf_sensor *sr)
 374 {
 375         if (!try_module_get(sr->ops->owner))
 376                 return -ENODEV;
 377         kref_get(&sr->ref);
 378         return 0;
 379 }
 380 EXPORT_SYMBOL_GPL(wf_get_sensor);
 381
 382 void wf_put_sensor(struct wf_sensor *sr)
 383 {
 384         struct module *mod = sr->ops->owner;
 385         kref_put(&sr->ref, wf_sensor_release);
 386         module_put(mod);
 387 }
 388 EXPORT_SYMBOL_GPL(wf_put_sensor);
 389
 390
 391 /*
 392  * Client & notification
 393  */
 394
 395 int wf_register_client(struct notifier_block *nb)
 396 {
 397         int rc;
 398         struct wf_control *ct;
 399         struct wf_sensor *sr;
 400
 401         mutex_lock(&wf_lock);
 402         rc = blocking_notifier_chain_register(&wf_client_list, nb);
 403         if (rc != 0)
 404                 goto bail;
 405         wf_client_count++;
 406         list_for_each_entry(ct, &wf_controls, link)
 407                 wf_notify(WF_EVENT_NEW_CONTROL, ct);
 408         list_for_each_entry(sr, &wf_sensors, link)
 409                 wf_notify(WF_EVENT_NEW_SENSOR, sr);
 410         if (wf_client_count == 1)
 411                 wf_start_thread();
 412  bail:
 413         mutex_unlock(&wf_lock);
 414         return rc;
 415 }
 416 EXPORT_SYMBOL_GPL(wf_register_client);
 417
 418 int wf_unregister_client(struct notifier_block *nb)
 419 {
 420         mutex_lock(&wf_lock);
 421         blocking_notifier_chain_unregister(&wf_client_list, nb);
 422         wf_client_count++;
 423         if (wf_client_count == 0)
 424                 wf_stop_thread();
 425         mutex_unlock(&wf_lock);
 426
 427         return 0;
 428 }
 429 EXPORT_SYMBOL_GPL(wf_unregister_client);
 430
 431 void wf_set_overtemp(void)
 432 {
 433         mutex_lock(&wf_lock);
 434         wf_overtemp++;
 435         if (wf_overtemp == 1) {
 436                 printk(KERN_WARNING "windfarm: Overtemp condition detected !\n");
 437                 wf_overtemp_counter = 0;
 438                 wf_notify(WF_EVENT_OVERTEMP, NULL);
 439         }
 440         mutex_unlock(&wf_lock);
 441 }
 442 EXPORT_SYMBOL_GPL(wf_set_overtemp);
 443
 444 void wf_clear_overtemp(void)
 445 {
 446         mutex_lock(&wf_lock);
 447         WARN_ON(wf_overtemp == 0);
 448         if (wf_overtemp == 0) {
 449                 mutex_unlock(&wf_lock);
 450                 return;
 451         }
 452         wf_overtemp--;
 453         if (wf_overtemp == 0) {
 454                 printk(KERN_WARNING "windfarm: Overtemp condition cleared !\n");
 455                 wf_notify(WF_EVENT_NORMALTEMP, NULL);
 456         }
 457         mutex_unlock(&wf_lock);
 458 }
 459 EXPORT_SYMBOL_GPL(wf_clear_overtemp);
 460
 461 int wf_is_overtemp(void)
 462 {
 463         return (wf_overtemp != 0);
 464 }
 465 EXPORT_SYMBOL_GPL(wf_is_overtemp);
 466
 467 static int __init windfarm_core_init(void)
 468 {
 469         DBG("wf: core loaded\n");
 470
 471         /* Don't register on old machines that use therm_pm72 for now */
 472         if (machine_is_compatible("PowerMac7,2") ||
 473             machine_is_compatible("PowerMac7,3") ||
 474             machine_is_compatible("RackMac3,1"))
 475                 return -ENODEV;
 476         platform_device_register(&wf_platform_device);
 477         return 0;
 478 }
 479
 480 static void __exit windfarm_core_exit(void)
 481 {
 482         BUG_ON(wf_client_count != 0);
 483
 484         DBG("wf: core unloaded\n");
 485
 486         platform_device_unregister(&wf_platform_device);
 487 }
 488
 489
 490 module_init(windfarm_core_init);
 491 module_exit(windfarm_core_exit);
 492
 493 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 494 MODULE_DESCRIPTION("Core component of PowerMac thermal control");
 495 MODULE_LICENSE("GPL");
 496