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
  38 #include "windfarm.h"
  39
  40 #define VERSION "0.2"
  41
  42 #undef DEBUG
  43
  44 #ifdef DEBUG
  45 #define DBG(args...)    printk(args)
  46 #else
  47 #define DBG(args...)    do { } while(0)
  48 #endif
  49
  50 static LIST_HEAD(wf_controls);
  51 static LIST_HEAD(wf_sensors);
  52 static DEFINE_MUTEX(wf_lock);
  53 static struct notifier_block *wf_client_list;
  54 static int wf_client_count;
  55 static unsigned int wf_overtemp;
  56 static unsigned int wf_overtemp_counter;
  57 struct task_struct *wf_thread;
  58
  59 /*
  60  * Utilities & tick thread
  61  */
  62
  63 static inline void wf_notify(int event, void *param)
  64 {
  65         notifier_call_chain(&wf_client_list, event, param);
  66 }
  67
  68 int wf_critical_overtemp(void)
  69 {
  70         static char * critical_overtemp_path = "/sbin/critical_overtemp";
  71         char *argv[] = { critical_overtemp_path, NULL };
  72         static char *envp[] = { "HOME=/",
  73                                 "TERM=linux",
  74                                 "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
  75                                 NULL };
  76
  77         return call_usermodehelper(critical_overtemp_path, argv, envp, 0);
  78 }
  79 EXPORT_SYMBOL_GPL(wf_critical_overtemp);
  80
  81 static int wf_thread_func(void *data)
  82 {
  83         unsigned long next, delay;
  84
  85         next = jiffies;
  86
  87         DBG("wf: thread started\n");
  88
  89         while(!kthread_should_stop()) {
  90                 try_to_freeze();
  91
  92                 if (time_after_eq(jiffies, next)) {
  93                         wf_notify(WF_EVENT_TICK, NULL);
  94                         if (wf_overtemp) {
  95                                 wf_overtemp_counter++;
  96                                 /* 10 seconds overtemp, notify userland */
  97                                 if (wf_overtemp_counter > 10)
  98                                         wf_critical_overtemp();
  99                                 /* 30 seconds, shutdown */
 100                                 if (wf_overtemp_counter > 30) {
 101                                         printk(KERN_ERR "windfarm: Overtemp "
 102                                                "for more than 30"
 103                                                " seconds, shutting down\n");
 104                                         machine_power_off();
 105                                 }
 106                         }
 107                         next += HZ;
 108                 }
 109
 110                 delay = next - jiffies;
 111                 if (delay <= HZ)
 112                         schedule_timeout_interruptible(delay);
 113
 114                 /* there should be no signal, but oh well */
 115                 if (signal_pending(current)) {
 116                         printk(KERN_WARNING "windfarm: thread got sigl !\n");
 117                         break;
 118                 }
 119         }
 120
 121         DBG("wf: thread stopped\n");
 122
 123         return 0;
 124 }
 125
 126 static void wf_start_thread(void)
 127 {
 128         wf_thread = kthread_run(wf_thread_func, NULL, "kwindfarm");
 129         if (IS_ERR(wf_thread)) {
 130                 printk(KERN_ERR "windfarm: failed to create thread,err %ld\n",
 131                        PTR_ERR(wf_thread));
 132                 wf_thread = NULL;
 133         }
 134 }
 135
 136
 137 static void wf_stop_thread(void)
 138 {
 139         if (wf_thread)
 140                 kthread_stop(wf_thread);
 141         wf_thread = NULL;
 142 }
 143
 144 /*
 145  * Controls
 146  */
 147
 148 static void wf_control_release(struct kref *kref)
 149 {
 150         struct wf_control *ct = container_of(kref, struct wf_control, ref);
 151
 152         DBG("wf: Deleting control %s\n", ct->name);
 153
 154         if (ct->ops && ct->ops->release)
 155                 ct->ops->release(ct);
 156         else
 157                 kfree(ct);
 158 }
 159
 160 int wf_register_control(struct wf_control *new_ct)
 161 {
 162         struct wf_control *ct;
 163
 164         mutex_lock(&wf_lock);
 165         list_for_each_entry(ct, &wf_controls, link) {
 166                 if (!strcmp(ct->name, new_ct->name)) {
 167                         printk(KERN_WARNING "windfarm: trying to register"
 168                                " duplicate control %s\n", ct->name);
 169                         mutex_unlock(&wf_lock);
 170                         return -EEXIST;
 171                 }
 172         }
 173         kref_init(&new_ct->ref);
 174         list_add(&new_ct->link, &wf_controls);
 175
 176         DBG("wf: Registered control %s\n", new_ct->name);
 177
 178         wf_notify(WF_EVENT_NEW_CONTROL, new_ct);
 179         mutex_unlock(&wf_lock);
 180
 181         return 0;
 182 }
 183 EXPORT_SYMBOL_GPL(wf_register_control);
 184
 185 void wf_unregister_control(struct wf_control *ct)
 186 {
 187         mutex_lock(&wf_lock);
 188         list_del(&ct->link);
 189         mutex_unlock(&wf_lock);
 190
 191         DBG("wf: Unregistered control %s\n", ct->name);
 192
 193         kref_put(&ct->ref, wf_control_release);
 194 }
 195 EXPORT_SYMBOL_GPL(wf_unregister_control);
 196
 197 struct wf_control * wf_find_control(const char *name)
 198 {
 199         struct wf_control *ct;
 200
 201         mutex_lock(&wf_lock);
 202         list_for_each_entry(ct, &wf_controls, link) {
 203                 if (!strcmp(ct->name, name)) {
 204                         if (wf_get_control(ct))
 205                                 ct = NULL;
 206                         mutex_unlock(&wf_lock);
 207                         return ct;
 208                 }
 209         }
 210         mutex_unlock(&wf_lock);
 211         return NULL;
 212 }
 213 EXPORT_SYMBOL_GPL(wf_find_control);
 214
 215 int wf_get_control(struct wf_control *ct)
 216 {
 217         if (!try_module_get(ct->ops->owner))
 218                 return -ENODEV;
 219         kref_get(&ct->ref);
 220         return 0;
 221 }
 222 EXPORT_SYMBOL_GPL(wf_get_control);
 223
 224 void wf_put_control(struct wf_control *ct)
 225 {
 226         struct module *mod = ct->ops->owner;
 227         kref_put(&ct->ref, wf_control_release);
 228         module_put(mod);
 229 }
 230 EXPORT_SYMBOL_GPL(wf_put_control);
 231
 232
 233 /*
 234  * Sensors
 235  */
 236
 237
 238 static void wf_sensor_release(struct kref *kref)
 239 {
 240         struct wf_sensor *sr = container_of(kref, struct wf_sensor, ref);
 241
 242         DBG("wf: Deleting sensor %s\n", sr->name);
 243
 244         if (sr->ops && sr->ops->release)
 245                 sr->ops->release(sr);
 246         else
 247                 kfree(sr);
 248 }
 249
 250 int wf_register_sensor(struct wf_sensor *new_sr)
 251 {
 252         struct wf_sensor *sr;
 253
 254         mutex_lock(&wf_lock);
 255         list_for_each_entry(sr, &wf_sensors, link) {
 256                 if (!strcmp(sr->name, new_sr->name)) {
 257                         printk(KERN_WARNING "windfarm: trying to register"
 258                                " duplicate sensor %s\n", sr->name);
 259                         mutex_unlock(&wf_lock);
 260                         return -EEXIST;
 261                 }
 262         }
 263         kref_init(&new_sr->ref);
 264         list_add(&new_sr->link, &wf_sensors);
 265
 266         DBG("wf: Registered sensor %s\n", new_sr->name);
 267
 268         wf_notify(WF_EVENT_NEW_SENSOR, new_sr);
 269         mutex_unlock(&wf_lock);
 270
 271         return 0;
 272 }
 273 EXPORT_SYMBOL_GPL(wf_register_sensor);
 274
 275 void wf_unregister_sensor(struct wf_sensor *sr)
 276 {
 277         mutex_lock(&wf_lock);
 278         list_del(&sr->link);
 279         mutex_unlock(&wf_lock);
 280
 281         DBG("wf: Unregistered sensor %s\n", sr->name);
 282
 283         wf_put_sensor(sr);
 284 }
 285 EXPORT_SYMBOL_GPL(wf_unregister_sensor);
 286
 287 struct wf_sensor * wf_find_sensor(const char *name)
 288 {
 289         struct wf_sensor *sr;
 290
 291         mutex_lock(&wf_lock);
 292         list_for_each_entry(sr, &wf_sensors, link) {
 293                 if (!strcmp(sr->name, name)) {
 294                         if (wf_get_sensor(sr))
 295                                 sr = NULL;
 296                         mutex_unlock(&wf_lock);
 297                         return sr;
 298                 }
 299         }
 300         mutex_unlock(&wf_lock);
 301         return NULL;
 302 }
 303 EXPORT_SYMBOL_GPL(wf_find_sensor);
 304
 305 int wf_get_sensor(struct wf_sensor *sr)
 306 {
 307         if (!try_module_get(sr->ops->owner))
 308                 return -ENODEV;
 309         kref_get(&sr->ref);
 310         return 0;
 311 }
 312 EXPORT_SYMBOL_GPL(wf_get_sensor);
 313
 314 void wf_put_sensor(struct wf_sensor *sr)
 315 {
 316         struct module *mod = sr->ops->owner;
 317         kref_put(&sr->ref, wf_sensor_release);
 318         module_put(mod);
 319 }
 320 EXPORT_SYMBOL_GPL(wf_put_sensor);
 321
 322
 323 /*
 324  * Client & notification
 325  */
 326
 327 int wf_register_client(struct notifier_block *nb)
 328 {
 329         int rc;
 330         struct wf_control *ct;
 331         struct wf_sensor *sr;
 332
 333         mutex_lock(&wf_lock);
 334         rc = notifier_chain_register(&wf_client_list, nb);
 335         if (rc != 0)
 336                 goto bail;
 337         wf_client_count++;
 338         list_for_each_entry(ct, &wf_controls, link)
 339                 wf_notify(WF_EVENT_NEW_CONTROL, ct);
 340         list_for_each_entry(sr, &wf_sensors, link)
 341                 wf_notify(WF_EVENT_NEW_SENSOR, sr);
 342         if (wf_client_count == 1)
 343                 wf_start_thread();
 344  bail:
 345         mutex_unlock(&wf_lock);
 346         return rc;
 347 }
 348 EXPORT_SYMBOL_GPL(wf_register_client);
 349
 350 int wf_unregister_client(struct notifier_block *nb)
 351 {
 352         mutex_lock(&wf_lock);
 353         notifier_chain_unregister(&wf_client_list, nb);
 354         wf_client_count++;
 355         if (wf_client_count == 0)
 356                 wf_stop_thread();
 357         mutex_unlock(&wf_lock);
 358
 359         return 0;
 360 }
 361 EXPORT_SYMBOL_GPL(wf_unregister_client);
 362
 363 void wf_set_overtemp(void)
 364 {
 365         mutex_lock(&wf_lock);
 366         wf_overtemp++;
 367         if (wf_overtemp == 1) {
 368                 printk(KERN_WARNING "windfarm: Overtemp condition detected !\n");
 369                 wf_overtemp_counter = 0;
 370                 wf_notify(WF_EVENT_OVERTEMP, NULL);
 371         }
 372         mutex_unlock(&wf_lock);
 373 }
 374 EXPORT_SYMBOL_GPL(wf_set_overtemp);
 375
 376 void wf_clear_overtemp(void)
 377 {
 378         mutex_lock(&wf_lock);
 379         WARN_ON(wf_overtemp == 0);
 380         if (wf_overtemp == 0) {
 381                 mutex_unlock(&wf_lock);
 382                 return;
 383         }
 384         wf_overtemp--;
 385         if (wf_overtemp == 0) {
 386                 printk(KERN_WARNING "windfarm: Overtemp condition cleared !\n");
 387                 wf_notify(WF_EVENT_NORMALTEMP, NULL);
 388         }
 389         mutex_unlock(&wf_lock);
 390 }
 391 EXPORT_SYMBOL_GPL(wf_clear_overtemp);
 392
 393 int wf_is_overtemp(void)
 394 {
 395         return (wf_overtemp != 0);
 396 }
 397 EXPORT_SYMBOL_GPL(wf_is_overtemp);
 398
 399 static struct platform_device wf_platform_device = {
 400         .name   = "windfarm",
 401 };
 402
 403 static int __init windfarm_core_init(void)
 404 {
 405         DBG("wf: core loaded\n");
 406
 407         platform_device_register(&wf_platform_device);
 408         return 0;
 409 }
 410
 411 static void __exit windfarm_core_exit(void)
 412 {
 413         BUG_ON(wf_client_count != 0);
 414
 415         DBG("wf: core unloaded\n");
 416
 417         platform_device_unregister(&wf_platform_device);
 418 }
 419
 420
 421 module_init(windfarm_core_init);
 422 module_exit(windfarm_core_exit);
 423
 424 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 425 MODULE_DESCRIPTION("Core component of PowerMac thermal control");
 426 MODULE_LICENSE("GPL");
 427