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         set_freezable();
  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.mode = 0644;
 217         new_ct->attr.show = wf_show_control;
 218         new_ct->attr.store = wf_store_control;
 219         if (device_create_file(&wf_platform_device.dev, &new_ct->attr))
 220                 printk(KERN_WARNING "windfarm: device_create_file failed"
 221                         " for %s\n", new_ct->name);
 222                 /* the subsystem still does useful work without the file */
 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.mode = 0444;
 329         new_sr->attr.show = wf_show_sensor;
 330         new_sr->attr.store = NULL;
 331         if (device_create_file(&wf_platform_device.dev, &new_sr->attr))
 332                 printk(KERN_WARNING "windfarm: device_create_file failed"
 333                         " for %s\n", new_sr->name);
 334                 /* the subsystem still does useful work without the file */
 335
 336         DBG("wf: Registered sensor %s\n", new_sr->name);
 337
 338         wf_notify(WF_EVENT_NEW_SENSOR, new_sr);
 339         mutex_unlock(&wf_lock);
 340
 341         return 0;
 342 }
 343 EXPORT_SYMBOL_GPL(wf_register_sensor);
 344
 345 void wf_unregister_sensor(struct wf_sensor *sr)
 346 {
 347         mutex_lock(&wf_lock);
 348         list_del(&sr->link);
 349         mutex_unlock(&wf_lock);
 350
 351         DBG("wf: Unregistered sensor %s\n", sr->name);
 352
 353         wf_put_sensor(sr);
 354 }
 355 EXPORT_SYMBOL_GPL(wf_unregister_sensor);
 356
 357 struct wf_sensor * wf_find_sensor(const char *name)
 358 {
 359         struct wf_sensor *sr;
 360
 361         mutex_lock(&wf_lock);
 362         list_for_each_entry(sr, &wf_sensors, link) {
 363                 if (!strcmp(sr->name, name)) {
 364                         if (wf_get_sensor(sr))
 365                                 sr = NULL;
 366                         mutex_unlock(&wf_lock);
 367                         return sr;
 368                 }
 369         }
 370         mutex_unlock(&wf_lock);
 371         return NULL;
 372 }
 373 EXPORT_SYMBOL_GPL(wf_find_sensor);
 374
 375 int wf_get_sensor(struct wf_sensor *sr)
 376 {
 377         if (!try_module_get(sr->ops->owner))
 378                 return -ENODEV;
 379         kref_get(&sr->ref);
 380         return 0;
 381 }
 382 EXPORT_SYMBOL_GPL(wf_get_sensor);
 383
 384 void wf_put_sensor(struct wf_sensor *sr)
 385 {
 386         struct module *mod = sr->ops->owner;
 387         kref_put(&sr->ref, wf_sensor_release);
 388         module_put(mod);
 389 }
 390 EXPORT_SYMBOL_GPL(wf_put_sensor);
 391
 392
 393 /*
 394  * Client & notification
 395  */
 396
 397 int wf_register_client(struct notifier_block *nb)
 398 {
 399         int rc;
 400         struct wf_control *ct;
 401         struct wf_sensor *sr;
 402
 403         mutex_lock(&wf_lock);
 404         rc = blocking_notifier_chain_register(&wf_client_list, nb);
 405         if (rc != 0)
 406                 goto bail;
 407         wf_client_count++;
 408         list_for_each_entry(ct, &wf_controls, link)
 409                 wf_notify(WF_EVENT_NEW_CONTROL, ct);
 410         list_for_each_entry(sr, &wf_sensors, link)
 411                 wf_notify(WF_EVENT_NEW_SENSOR, sr);
 412         if (wf_client_count == 1)
 413                 wf_start_thread();
 414  bail:
 415         mutex_unlock(&wf_lock);
 416         return rc;
 417 }
 418 EXPORT_SYMBOL_GPL(wf_register_client);
 419
 420 int wf_unregister_client(struct notifier_block *nb)
 421 {
 422         mutex_lock(&wf_lock);
 423         blocking_notifier_chain_unregister(&wf_client_list, nb);
 424         wf_client_count++;
 425         if (wf_client_count == 0)
 426                 wf_stop_thread();
 427         mutex_unlock(&wf_lock);
 428
 429         return 0;
 430 }
 431 EXPORT_SYMBOL_GPL(wf_unregister_client);
 432
 433 void wf_set_overtemp(void)
 434 {
 435         mutex_lock(&wf_lock);
 436         wf_overtemp++;
 437         if (wf_overtemp == 1) {
 438                 printk(KERN_WARNING "windfarm: Overtemp condition detected !\n");
 439                 wf_overtemp_counter = 0;
 440                 wf_notify(WF_EVENT_OVERTEMP, NULL);
 441         }
 442         mutex_unlock(&wf_lock);
 443 }
 444 EXPORT_SYMBOL_GPL(wf_set_overtemp);
 445
 446 void wf_clear_overtemp(void)
 447 {
 448         mutex_lock(&wf_lock);
 449         WARN_ON(wf_overtemp == 0);
 450         if (wf_overtemp == 0) {
 451                 mutex_unlock(&wf_lock);
 452                 return;
 453         }
 454         wf_overtemp--;
 455         if (wf_overtemp == 0) {
 456                 printk(KERN_WARNING "windfarm: Overtemp condition cleared !\n");
 457                 wf_notify(WF_EVENT_NORMALTEMP, NULL);
 458         }
 459         mutex_unlock(&wf_lock);
 460 }
 461 EXPORT_SYMBOL_GPL(wf_clear_overtemp);
 462
 463 int wf_is_overtemp(void)
 464 {
 465         return (wf_overtemp != 0);
 466 }
 467 EXPORT_SYMBOL_GPL(wf_is_overtemp);
 468
 469 static int __init windfarm_core_init(void)
 470 {
 471         DBG("wf: core loaded\n");
 472
 473         /* Don't register on old machines that use therm_pm72 for now */
 474         if (machine_is_compatible("PowerMac7,2") ||
 475             machine_is_compatible("PowerMac7,3") ||
 476             machine_is_compatible("RackMac3,1"))
 477                 return -ENODEV;
 478         platform_device_register(&wf_platform_device);
 479         return 0;
 480 }
 481
 482 static void __exit windfarm_core_exit(void)
 483 {
 484         BUG_ON(wf_client_count != 0);
 485
 486         DBG("wf: core unloaded\n");
 487
 488         platform_device_unregister(&wf_platform_device);
 489 }
 490
 491
 492 module_init(windfarm_core_init);
 493 module_exit(windfarm_core_exit);
 494
 495 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 496 MODULE_DESCRIPTION("Core component of PowerMac thermal control");
 497 MODULE_LICENSE("GPL");
 498