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, argv, envp, 0);
  84 }
  85 EXPORT_SYMBOL_GPL(wf_critical_overtemp);
  86
  87 static int wf_thread_func(void *data)
  88 {
  89         unsigned long next, delay;
  90
  91         next = jiffies;
  92
  93         DBG("wf: thread started\n");
  94
  95         while(!kthread_should_stop()) {
  96                 if (time_after_eq(jiffies, next)) {
  97                         wf_notify(WF_EVENT_TICK, NULL);
  98                         if (wf_overtemp) {
  99                                 wf_overtemp_counter++;
 100                                 /* 10 seconds overtemp, notify userland */
 101                                 if (wf_overtemp_counter > 10)
 102                                         wf_critical_overtemp();
 103                                 /* 30 seconds, shutdown */
 104                                 if (wf_overtemp_counter > 30) {
 105                                         printk(KERN_ERR "windfarm: Overtemp "
 106                                                "for more than 30"
 107                                                " seconds, shutting down\n");
 108                                         machine_power_off();
 109                                 }
 110                         }
 111                         next += HZ;
 112                 }
 113
 114                 delay = next - jiffies;
 115                 if (delay <= HZ)
 116                         schedule_timeout_interruptible(delay);
 117
 118                 /* there should be no non-suspend signal, but oh well */
 119                 if (signal_pending(current) && !try_to_freeze()) {
 120                         printk(KERN_WARNING "windfarm: thread got sigl !\n");
 121                         break;
 122                 }
 123         }
 124
 125         DBG("wf: thread stopped\n");
 126
 127         return 0;
 128 }
 129
 130 static void wf_start_thread(void)
 131 {
 132         wf_thread = kthread_run(wf_thread_func, NULL, "kwindfarm");
 133         if (IS_ERR(wf_thread)) {
 134                 printk(KERN_ERR "windfarm: failed to create thread,err %ld\n",
 135                        PTR_ERR(wf_thread));
 136                 wf_thread = NULL;
 137         }
 138 }
 139
 140
 141 static void wf_stop_thread(void)
 142 {
 143         if (wf_thread)
 144                 kthread_stop(wf_thread);
 145         wf_thread = NULL;
 146 }
 147
 148 /*
 149  * Controls
 150  */
 151
 152 static void wf_control_release(struct kref *kref)
 153 {
 154         struct wf_control *ct = container_of(kref, struct wf_control, ref);
 155
 156         DBG("wf: Deleting control %s\n", ct->name);
 157
 158         if (ct->ops && ct->ops->release)
 159                 ct->ops->release(ct);
 160         else
 161                 kfree(ct);
 162 }
 163
 164 static ssize_t wf_show_control(struct device *dev,
 165                                struct device_attribute *attr, char *buf)
 166 {
 167         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
 168         s32 val = 0;
 169         int err;
 170
 171         err = ctrl->ops->get_value(ctrl, &val);
 172         if (err < 0)
 173                 return err;
 174         return sprintf(buf, "%d\n", val);
 175 }
 176
 177 /* This is really only for debugging... */
 178 static ssize_t wf_store_control(struct device *dev,
 179                                 struct device_attribute *attr,
 180                                 const char *buf, size_t count)
 181 {
 182         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
 183         int val;
 184         int err;
 185         char *endp;
 186
 187         val = simple_strtoul(buf, &endp, 0);
 188         while (endp < buf + count && (*endp == ' ' || *endp == '\n'))
 189                 ++endp;
 190         if (endp - buf < count)
 191                 return -EINVAL;
 192         err = ctrl->ops->set_value(ctrl, val);
 193         if (err < 0)
 194                 return err;
 195         return count;
 196 }
 197
 198 int wf_register_control(struct wf_control *new_ct)
 199 {
 200         struct wf_control *ct;
 201
 202         mutex_lock(&wf_lock);
 203         list_for_each_entry(ct, &wf_controls, link) {
 204                 if (!strcmp(ct->name, new_ct->name)) {
 205                         printk(KERN_WARNING "windfarm: trying to register"
 206                                " duplicate control %s\n", ct->name);
 207                         mutex_unlock(&wf_lock);
 208                         return -EEXIST;
 209                 }
 210         }
 211         kref_init(&new_ct->ref);
 212         list_add(&new_ct->link, &wf_controls);
 213
 214         new_ct->attr.attr.name = new_ct->name;
 215         new_ct->attr.attr.mode = 0644;
 216         new_ct->attr.show = wf_show_control;
 217         new_ct->attr.store = wf_store_control;
 218         if (device_create_file(&wf_platform_device.dev, &new_ct->attr))
 219                 printk(KERN_WARNING "windfarm: device_create_file failed"
 220                         " for %s\n", new_ct->name);
 221                 /* the subsystem still does useful work without the file */
 222
 223         DBG("wf: Registered control %s\n", new_ct->name);
 224
 225         wf_notify(WF_EVENT_NEW_CONTROL, new_ct);
 226         mutex_unlock(&wf_lock);
 227
 228         return 0;
 229 }
 230 EXPORT_SYMBOL_GPL(wf_register_control);
 231
 232 void wf_unregister_control(struct wf_control *ct)
 233 {
 234         mutex_lock(&wf_lock);
 235         list_del(&ct->link);
 236         mutex_unlock(&wf_lock);
 237
 238         DBG("wf: Unregistered control %s\n", ct->name);
 239
 240         kref_put(&ct->ref, wf_control_release);
 241 }
 242 EXPORT_SYMBOL_GPL(wf_unregister_control);
 243
 244 struct wf_control * wf_find_control(const char *name)
 245 {
 246         struct wf_control *ct;
 247
 248         mutex_lock(&wf_lock);
 249         list_for_each_entry(ct, &wf_controls, link) {
 250                 if (!strcmp(ct->name, name)) {
 251                         if (wf_get_control(ct))
 252                                 ct = NULL;
 253                         mutex_unlock(&wf_lock);
 254                         return ct;
 255                 }
 256         }
 257         mutex_unlock(&wf_lock);
 258         return NULL;
 259 }
 260 EXPORT_SYMBOL_GPL(wf_find_control);
 261
 262 int wf_get_control(struct wf_control *ct)
 263 {
 264         if (!try_module_get(ct->ops->owner))
 265                 return -ENODEV;
 266         kref_get(&ct->ref);
 267         return 0;
 268 }
 269 EXPORT_SYMBOL_GPL(wf_get_control);
 270
 271 void wf_put_control(struct wf_control *ct)
 272 {
 273         struct module *mod = ct->ops->owner;
 274         kref_put(&ct->ref, wf_control_release);
 275         module_put(mod);
 276 }
 277 EXPORT_SYMBOL_GPL(wf_put_control);
 278
 279
 280 /*
 281  * Sensors
 282  */
 283
 284
 285 static void wf_sensor_release(struct kref *kref)
 286 {
 287         struct wf_sensor *sr = container_of(kref, struct wf_sensor, ref);
 288
 289         DBG("wf: Deleting sensor %s\n", sr->name);
 290
 291         if (sr->ops && sr->ops->release)
 292                 sr->ops->release(sr);
 293         else
 294                 kfree(sr);
 295 }
 296
 297 static ssize_t wf_show_sensor(struct device *dev,
 298                               struct device_attribute *attr, char *buf)
 299 {
 300         struct wf_sensor *sens = container_of(attr, struct wf_sensor, attr);
 301         s32 val = 0;
 302         int err;
 303
 304         err = sens->ops->get_value(sens, &val);
 305         if (err < 0)
 306                 return err;
 307         return sprintf(buf, "%d.%03d\n", FIX32TOPRINT(val));
 308 }
 309
 310 int wf_register_sensor(struct wf_sensor *new_sr)
 311 {
 312         struct wf_sensor *sr;
 313
 314         mutex_lock(&wf_lock);
 315         list_for_each_entry(sr, &wf_sensors, link) {
 316                 if (!strcmp(sr->name, new_sr->name)) {
 317                         printk(KERN_WARNING "windfarm: trying to register"
 318                                " duplicate sensor %s\n", sr->name);
 319                         mutex_unlock(&wf_lock);
 320                         return -EEXIST;
 321                 }
 322         }
 323         kref_init(&new_sr->ref);
 324         list_add(&new_sr->link, &wf_sensors);
 325
 326         new_sr->attr.attr.name = new_sr->name;
 327         new_sr->attr.attr.mode = 0444;
 328         new_sr->attr.show = wf_show_sensor;
 329         new_sr->attr.store = NULL;
 330         if (device_create_file(&wf_platform_device.dev, &new_sr->attr))
 331                 printk(KERN_WARNING "windfarm: device_create_file failed"
 332                         " for %s\n", new_sr->name);
 333                 /* the subsystem still does useful work without the file */
 334
 335         DBG("wf: Registered sensor %s\n", new_sr->name);
 336
 337         wf_notify(WF_EVENT_NEW_SENSOR, new_sr);
 338         mutex_unlock(&wf_lock);
 339
 340         return 0;
 341 }
 342 EXPORT_SYMBOL_GPL(wf_register_sensor);
 343
 344 void wf_unregister_sensor(struct wf_sensor *sr)
 345 {
 346         mutex_lock(&wf_lock);
 347         list_del(&sr->link);
 348         mutex_unlock(&wf_lock);
 349
 350         DBG("wf: Unregistered sensor %s\n", sr->name);
 351
 352         wf_put_sensor(sr);
 353 }
 354 EXPORT_SYMBOL_GPL(wf_unregister_sensor);
 355
 356 struct wf_sensor * wf_find_sensor(const char *name)
 357 {
 358         struct wf_sensor *sr;
 359
 360         mutex_lock(&wf_lock);
 361         list_for_each_entry(sr, &wf_sensors, link) {
 362                 if (!strcmp(sr->name, name)) {
 363                         if (wf_get_sensor(sr))
 364                                 sr = NULL;
 365                         mutex_unlock(&wf_lock);
 366                         return sr;
 367                 }
 368         }
 369         mutex_unlock(&wf_lock);
 370         return NULL;
 371 }
 372 EXPORT_SYMBOL_GPL(wf_find_sensor);
 373
 374 int wf_get_sensor(struct wf_sensor *sr)
 375 {
 376         if (!try_module_get(sr->ops->owner))
 377                 return -ENODEV;
 378         kref_get(&sr->ref);
 379         return 0;
 380 }
 381 EXPORT_SYMBOL_GPL(wf_get_sensor);
 382
 383 void wf_put_sensor(struct wf_sensor *sr)
 384 {
 385         struct module *mod = sr->ops->owner;
 386         kref_put(&sr->ref, wf_sensor_release);
 387         module_put(mod);
 388 }
 389 EXPORT_SYMBOL_GPL(wf_put_sensor);
 390
 391
 392 /*
 393  * Client & notification
 394  */
 395
 396 int wf_register_client(struct notifier_block *nb)
 397 {
 398         int rc;
 399         struct wf_control *ct;
 400         struct wf_sensor *sr;
 401
 402         mutex_lock(&wf_lock);
 403         rc = blocking_notifier_chain_register(&wf_client_list, nb);
 404         if (rc != 0)
 405                 goto bail;
 406         wf_client_count++;
 407         list_for_each_entry(ct, &wf_controls, link)
 408                 wf_notify(WF_EVENT_NEW_CONTROL, ct);
 409         list_for_each_entry(sr, &wf_sensors, link)
 410                 wf_notify(WF_EVENT_NEW_SENSOR, sr);
 411         if (wf_client_count == 1)
 412                 wf_start_thread();
 413  bail:
 414         mutex_unlock(&wf_lock);
 415         return rc;
 416 }
 417 EXPORT_SYMBOL_GPL(wf_register_client);
 418
 419 int wf_unregister_client(struct notifier_block *nb)
 420 {
 421         mutex_lock(&wf_lock);
 422         blocking_notifier_chain_unregister(&wf_client_list, nb);
 423         wf_client_count++;
 424         if (wf_client_count == 0)
 425                 wf_stop_thread();
 426         mutex_unlock(&wf_lock);
 427
 428         return 0;
 429 }
 430 EXPORT_SYMBOL_GPL(wf_unregister_client);
 431
 432 void wf_set_overtemp(void)
 433 {
 434         mutex_lock(&wf_lock);
 435         wf_overtemp++;
 436         if (wf_overtemp == 1) {
 437                 printk(KERN_WARNING "windfarm: Overtemp condition detected !\n");
 438                 wf_overtemp_counter = 0;
 439                 wf_notify(WF_EVENT_OVERTEMP, NULL);
 440         }
 441         mutex_unlock(&wf_lock);
 442 }
 443 EXPORT_SYMBOL_GPL(wf_set_overtemp);
 444
 445 void wf_clear_overtemp(void)
 446 {
 447         mutex_lock(&wf_lock);
 448         WARN_ON(wf_overtemp == 0);
 449         if (wf_overtemp == 0) {
 450                 mutex_unlock(&wf_lock);
 451                 return;
 452         }
 453         wf_overtemp--;
 454         if (wf_overtemp == 0) {
 455                 printk(KERN_WARNING "windfarm: Overtemp condition cleared !\n");
 456                 wf_notify(WF_EVENT_NORMALTEMP, NULL);
 457         }
 458         mutex_unlock(&wf_lock);
 459 }
 460 EXPORT_SYMBOL_GPL(wf_clear_overtemp);
 461
 462 int wf_is_overtemp(void)
 463 {
 464         return (wf_overtemp != 0);
 465 }
 466 EXPORT_SYMBOL_GPL(wf_is_overtemp);
 467
 468 static int __init windfarm_core_init(void)
 469 {
 470         DBG("wf: core loaded\n");
 471
 472         /* Don't register on old machines that use therm_pm72 for now */
 473         if (machine_is_compatible("PowerMac7,2") ||
 474             machine_is_compatible("PowerMac7,3") ||
 475             machine_is_compatible("RackMac3,1"))
 476                 return -ENODEV;
 477         platform_device_register(&wf_platform_device);
 478         return 0;
 479 }
 480
 481 static void __exit windfarm_core_exit(void)
 482 {
 483         BUG_ON(wf_client_count != 0);
 484
 485         DBG("wf: core unloaded\n");
 486
 487         platform_device_unregister(&wf_platform_device);
 488 }
 489
 490
 491 module_init(windfarm_core_init);
 492 module_exit(windfarm_core_exit);
 493
 494 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 495 MODULE_DESCRIPTION("Core component of PowerMac thermal control");
 496 MODULE_LICENSE("GPL");
 497