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/kthread.h>
  31 #include <linux/jiffies.h>
  32 #include <linux/reboot.h>
  33 #include <linux/device.h>
  34 #include <linux/platform_device.h>
  35 #include <linux/mutex.h>
  36 #include <linux/freezer.h>
  37
  38 #include <asm/prom.h>
  39
  40 #include "windfarm.h"
  41
  42 #define VERSION "0.2"
  43
  44 #undef DEBUG
  45
  46 #ifdef DEBUG
  47 #define DBG(args...)    printk(args)
  48 #else
  49 #define DBG(args...)    do { } while(0)
  50 #endif
  51
  52 static LIST_HEAD(wf_controls);
  53 static LIST_HEAD(wf_sensors);
  54 static DEFINE_MUTEX(wf_lock);
  55 static BLOCKING_NOTIFIER_HEAD(wf_client_list);
  56 static int wf_client_count;
  57 static unsigned int wf_overtemp;
  58 static unsigned int wf_overtemp_counter;
  59 struct task_struct *wf_thread;
  60
  61 static struct platform_device wf_platform_device = {
  62         .name   = "windfarm",
  63 };
  64
  65 /*
  66  * Utilities & tick thread
  67  */
  68
  69 static inline void wf_notify(int event, void *param)
  70 {
  71         blocking_notifier_call_chain(&wf_client_list, event, param);
  72 }
  73
  74 int wf_critical_overtemp(void)
  75 {
  76         static char * critical_overtemp_path = "/sbin/critical_overtemp";
  77         char *argv[] = { critical_overtemp_path, NULL };
  78         static char *envp[] = { "HOME=/",
  79                                 "TERM=linux",
  80                                 "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
  81                                 NULL };
  82
  83         return call_usermodehelper(critical_overtemp_path,
  84                                    argv, envp, UMH_WAIT_EXEC);
  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         set_freezable();
  97         while(!kthread_should_stop()) {
  98                 if (time_after_eq(jiffies, next)) {
  99                         wf_notify(WF_EVENT_TICK, NULL);
 100                         if (wf_overtemp) {
 101                                 wf_overtemp_counter++;
 102                                 /* 10 seconds overtemp, notify userland */
 103                                 if (wf_overtemp_counter > 10)
 104                                         wf_critical_overtemp();
 105                                 /* 30 seconds, shutdown */
 106                                 if (wf_overtemp_counter > 30) {
 107                                         printk(KERN_ERR "windfarm: Overtemp "
 108                                                "for more than 30"
 109                                                " seconds, shutting down\n");
 110                                         machine_power_off();
 111                                 }
 112                         }
 113                         next += HZ;
 114                 }
 115
 116                 delay = next - jiffies;
 117                 if (delay <= HZ)
 118                         schedule_timeout_interruptible(delay);
 119
 120                 /* there should be no non-suspend signal, but oh well */
 121                 if (signal_pending(current) && !try_to_freeze()) {
 122                         printk(KERN_WARNING "windfarm: thread got sigl !\n");
 123                         break;
 124                 }
 125         }
 126
 127         DBG("wf: thread stopped\n");
 128
 129         return 0;
 130 }
 131
 132 static void wf_start_thread(void)
 133 {
 134         wf_thread = kthread_run(wf_thread_func, NULL, "kwindfarm");
 135         if (IS_ERR(wf_thread)) {
 136                 printk(KERN_ERR "windfarm: failed to create thread,err %ld\n",
 137                        PTR_ERR(wf_thread));
 138                 wf_thread = NULL;
 139         }
 140 }
 141
 142
 143 static void wf_stop_thread(void)
 144 {
 145         if (wf_thread)
 146                 kthread_stop(wf_thread);
 147         wf_thread = NULL;
 148 }
 149
 150 /*
 151  * Controls
 152  */
 153
 154 static void wf_control_release(struct kref *kref)
 155 {
 156         struct wf_control *ct = container_of(kref, struct wf_control, ref);
 157
 158         DBG("wf: Deleting control %s\n", ct->name);
 159
 160         if (ct->ops && ct->ops->release)
 161                 ct->ops->release(ct);
 162         else
 163                 kfree(ct);
 164 }
 165
 166 static ssize_t wf_show_control(struct device *dev,
 167                                struct device_attribute *attr, char *buf)
 168 {
 169         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
 170         s32 val = 0;
 171         int err;
 172
 173         err = ctrl->ops->get_value(ctrl, &val);
 174         if (err < 0)
 175                 return err;
 176         return sprintf(buf, "%d\n", val);
 177 }
 178
 179 /* This is really only for debugging... */
 180 static ssize_t wf_store_control(struct device *dev,
 181                                 struct device_attribute *attr,
 182                                 const char *buf, size_t count)
 183 {
 184         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
 185         int val;
 186         int err;
 187         char *endp;
 188
 189         val = simple_strtoul(buf, &endp, 0);
 190         while (endp < buf + count && (*endp == ' ' || *endp == '\n'))
 191                 ++endp;
 192         if (endp - buf < count)
 193                 return -EINVAL;
 194         err = ctrl->ops->set_value(ctrl, val);
 195         if (err < 0)
 196                 return err;
 197         return count;
 198 }
 199
 200 int wf_register_control(struct wf_control *new_ct)
 201 {
 202         struct wf_control *ct;
 203
 204         mutex_lock(&wf_lock);
 205         list_for_each_entry(ct, &wf_controls, link) {
 206                 if (!strcmp(ct->name, new_ct->name)) {
 207                         printk(KERN_WARNING "windfarm: trying to register"
 208                                " duplicate control %s\n", ct->name);
 209                         mutex_unlock(&wf_lock);
 210                         return -EEXIST;
 211                 }
 212         }
 213         kref_init(&new_ct->ref);
 214         list_add(&new_ct->link, &wf_controls);
 215
 216         new_ct->attr.attr.name = new_ct->name;
 217         new_ct->attr.attr.mode = 0644;
 218         new_ct->attr.show = wf_show_control;
 219         new_ct->attr.store = wf_store_control;
 220         if (device_create_file(&wf_platform_device.dev, &new_ct->attr))
 221                 printk(KERN_WARNING "windfarm: device_create_file failed"
 222                         " for %s\n", new_ct->name);
 223                 /* the subsystem still does useful work without the file */
 224
 225         DBG("wf: Registered control %s\n", new_ct->name);
 226
 227         wf_notify(WF_EVENT_NEW_CONTROL, new_ct);
 228         mutex_unlock(&wf_lock);
 229
 230         return 0;
 231 }
 232 EXPORT_SYMBOL_GPL(wf_register_control);
 233
 234 void wf_unregister_control(struct wf_control *ct)
 235 {
 236         mutex_lock(&wf_lock);
 237         list_del(&ct->link);
 238         mutex_unlock(&wf_lock);
 239
 240         DBG("wf: Unregistered control %s\n", ct->name);
 241
 242         kref_put(&ct->ref, wf_control_release);
 243 }
 244 EXPORT_SYMBOL_GPL(wf_unregister_control);
 245
 246 struct wf_control * wf_find_control(const char *name)
 247 {
 248         struct wf_control *ct;
 249
 250         mutex_lock(&wf_lock);
 251         list_for_each_entry(ct, &wf_controls, link) {
 252                 if (!strcmp(ct->name, name)) {
 253                         if (wf_get_control(ct))
 254                                 ct = NULL;
 255                         mutex_unlock(&wf_lock);
 256                         return ct;
 257                 }
 258         }
 259         mutex_unlock(&wf_lock);
 260         return NULL;
 261 }
 262 EXPORT_SYMBOL_GPL(wf_find_control);
 263
 264 int wf_get_control(struct wf_control *ct)
 265 {
 266         if (!try_module_get(ct->ops->owner))
 267                 return -ENODEV;
 268         kref_get(&ct->ref);
 269         return 0;
 270 }
 271 EXPORT_SYMBOL_GPL(wf_get_control);
 272
 273 void wf_put_control(struct wf_control *ct)
 274 {
 275         struct module *mod = ct->ops->owner;
 276         kref_put(&ct->ref, wf_control_release);
 277         module_put(mod);
 278 }
 279 EXPORT_SYMBOL_GPL(wf_put_control);
 280
 281
 282 /*
 283  * Sensors
 284  */
 285
 286
 287 static void wf_sensor_release(struct kref *kref)
 288 {
 289         struct wf_sensor *sr = container_of(kref, struct wf_sensor, ref);
 290
 291         DBG("wf: Deleting sensor %s\n", sr->name);
 292
 293         if (sr->ops && sr->ops->release)
 294                 sr->ops->release(sr);
 295         else
 296                 kfree(sr);
 297 }
 298
 299 static ssize_t wf_show_sensor(struct device *dev,
 300                               struct device_attribute *attr, char *buf)
 301 {
 302         struct wf_sensor *sens = container_of(attr, struct wf_sensor, attr);
 303         s32 val = 0;
 304         int err;
 305
 306         err = sens->ops->get_value(sens, &val);
 307         if (err < 0)
 308                 return err;
 309         return sprintf(buf, "%d.%03d\n", FIX32TOPRINT(val));
 310 }
 311
 312 int wf_register_sensor(struct wf_sensor *new_sr)
 313 {
 314         struct wf_sensor *sr;
 315
 316         mutex_lock(&wf_lock);
 317         list_for_each_entry(sr, &wf_sensors, link) {
 318                 if (!strcmp(sr->name, new_sr->name)) {
 319                         printk(KERN_WARNING "windfarm: trying to register"
 320                                " duplicate sensor %s\n", sr->name);
 321                         mutex_unlock(&wf_lock);
 322                         return -EEXIST;
 323                 }
 324         }
 325         kref_init(&new_sr->ref);
 326         list_add(&new_sr->link, &wf_sensors);
 327
 328         new_sr->attr.attr.name = new_sr->name;
 329         new_sr->attr.attr.mode = 0444;
 330         new_sr->attr.show = wf_show_sensor;
 331         new_sr->attr.store = NULL;
 332         if (device_create_file(&wf_platform_device.dev, &new_sr->attr))
 333                 printk(KERN_WARNING "windfarm: device_create_file failed"
 334                         " for %s\n", new_sr->name);
 335                 /* the subsystem still does useful work without the file */
 336
 337         DBG("wf: Registered sensor %s\n", new_sr->name);
 338
 339         wf_notify(WF_EVENT_NEW_SENSOR, new_sr);
 340         mutex_unlock(&wf_lock);
 341
 342         return 0;
 343 }
 344 EXPORT_SYMBOL_GPL(wf_register_sensor);
 345
 346 void wf_unregister_sensor(struct wf_sensor *sr)
 347 {
 348         mutex_lock(&wf_lock);
 349         list_del(&sr->link);
 350         mutex_unlock(&wf_lock);
 351
 352         DBG("wf: Unregistered sensor %s\n", sr->name);
 353
 354         wf_put_sensor(sr);
 355 }
 356 EXPORT_SYMBOL_GPL(wf_unregister_sensor);
 357
 358 struct wf_sensor * wf_find_sensor(const char *name)
 359 {
 360         struct wf_sensor *sr;
 361
 362         mutex_lock(&wf_lock);
 363         list_for_each_entry(sr, &wf_sensors, link) {
 364                 if (!strcmp(sr->name, name)) {
 365                         if (wf_get_sensor(sr))
 366                                 sr = NULL;
 367                         mutex_unlock(&wf_lock);
 368                         return sr;
 369                 }
 370         }
 371         mutex_unlock(&wf_lock);
 372         return NULL;
 373 }
 374 EXPORT_SYMBOL_GPL(wf_find_sensor);
 375
 376 int wf_get_sensor(struct wf_sensor *sr)
 377 {
 378         if (!try_module_get(sr->ops->owner))
 379                 return -ENODEV;
 380         kref_get(&sr->ref);
 381         return 0;
 382 }
 383 EXPORT_SYMBOL_GPL(wf_get_sensor);
 384
 385 void wf_put_sensor(struct wf_sensor *sr)
 386 {
 387         struct module *mod = sr->ops->owner;
 388         kref_put(&sr->ref, wf_sensor_release);
 389         module_put(mod);
 390 }
 391 EXPORT_SYMBOL_GPL(wf_put_sensor);
 392
 393
 394 /*
 395  * Client & notification
 396  */
 397
 398 int wf_register_client(struct notifier_block *nb)
 399 {
 400         int rc;
 401         struct wf_control *ct;
 402         struct wf_sensor *sr;
 403
 404         mutex_lock(&wf_lock);
 405         rc = blocking_notifier_chain_register(&wf_client_list, nb);
 406         if (rc != 0)
 407                 goto bail;
 408         wf_client_count++;
 409         list_for_each_entry(ct, &wf_controls, link)
 410                 wf_notify(WF_EVENT_NEW_CONTROL, ct);
 411         list_for_each_entry(sr, &wf_sensors, link)
 412                 wf_notify(WF_EVENT_NEW_SENSOR, sr);
 413         if (wf_client_count == 1)
 414                 wf_start_thread();
 415  bail:
 416         mutex_unlock(&wf_lock);
 417         return rc;
 418 }
 419 EXPORT_SYMBOL_GPL(wf_register_client);
 420
 421 int wf_unregister_client(struct notifier_block *nb)
 422 {
 423         mutex_lock(&wf_lock);
 424         blocking_notifier_chain_unregister(&wf_client_list, nb);
 425         wf_client_count++;
 426         if (wf_client_count == 0)
 427                 wf_stop_thread();
 428         mutex_unlock(&wf_lock);
 429
 430         return 0;
 431 }
 432 EXPORT_SYMBOL_GPL(wf_unregister_client);
 433
 434 void wf_set_overtemp(void)
 435 {
 436         mutex_lock(&wf_lock);
 437         wf_overtemp++;
 438         if (wf_overtemp == 1) {
 439                 printk(KERN_WARNING "windfarm: Overtemp condition detected !\n");
 440                 wf_overtemp_counter = 0;
 441                 wf_notify(WF_EVENT_OVERTEMP, NULL);
 442         }
 443         mutex_unlock(&wf_lock);
 444 }
 445 EXPORT_SYMBOL_GPL(wf_set_overtemp);
 446
 447 void wf_clear_overtemp(void)
 448 {
 449         mutex_lock(&wf_lock);
 450         WARN_ON(wf_overtemp == 0);
 451         if (wf_overtemp == 0) {
 452                 mutex_unlock(&wf_lock);
 453                 return;
 454         }
 455         wf_overtemp--;
 456         if (wf_overtemp == 0) {
 457                 printk(KERN_WARNING "windfarm: Overtemp condition cleared !\n");
 458                 wf_notify(WF_EVENT_NORMALTEMP, NULL);
 459         }
 460         mutex_unlock(&wf_lock);
 461 }
 462 EXPORT_SYMBOL_GPL(wf_clear_overtemp);
 463
 464 int wf_is_overtemp(void)
 465 {
 466         return (wf_overtemp != 0);
 467 }
 468 EXPORT_SYMBOL_GPL(wf_is_overtemp);
 469
 470 static int __init windfarm_core_init(void)
 471 {
 472         DBG("wf: core loaded\n");
 473
 474         /* Don't register on old machines that use therm_pm72 for now */
 475         if (machine_is_compatible("PowerMac7,2") ||
 476             machine_is_compatible("PowerMac7,3") ||
 477             machine_is_compatible("RackMac3,1"))
 478                 return -ENODEV;
 479         platform_device_register(&wf_platform_device);
 480         return 0;
 481 }
 482
 483 static void __exit windfarm_core_exit(void)
 484 {
 485         BUG_ON(wf_client_count != 0);
 486
 487         DBG("wf: core unloaded\n");
 488
 489         platform_device_unregister(&wf_platform_device);
 490 }
 491
 492
 493 module_init(windfarm_core_init);
 494 module_exit(windfarm_core_exit);
 495
 496 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 497 MODULE_DESCRIPTION("Core component of PowerMac thermal control");
 498 MODULE_LICENSE("GPL");
 499