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/slab.h>
  29 #include <linux/init.h>
  30 #include <linux/spinlock.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,
  85                                    argv, envp, UMH_WAIT_EXEC);
  86 }
  87 EXPORT_SYMBOL_GPL(wf_critical_overtemp);
  88
  89 static int wf_thread_func(void *data)
  90 {
  91         unsigned long next, delay;
  92
  93         next = jiffies;
  94
  95         DBG("wf: thread started\n");
  96
  97         set_freezable();
  98         while (!kthread_should_stop()) {
  99                 try_to_freeze();
 100
 101                 if (time_after_eq(jiffies, next)) {
 102                         wf_notify(WF_EVENT_TICK, NULL);
 103                         if (wf_overtemp) {
 104                                 wf_overtemp_counter++;
 105                                 /* 10 seconds overtemp, notify userland */
 106                                 if (wf_overtemp_counter > 10)
 107                                         wf_critical_overtemp();
 108                                 /* 30 seconds, shutdown */
 109                                 if (wf_overtemp_counter > 30) {
 110                                         printk(KERN_ERR "windfarm: Overtemp "
 111                                                "for more than 30"
 112                                                " seconds, shutting down\n");
 113                                         machine_power_off();
 114                                 }
 115                         }
 116                         next += HZ;
 117                 }
 118
 119                 delay = next - jiffies;
 120                 if (delay <= HZ)
 121                         schedule_timeout_interruptible(delay);
 122         }
 123
 124         DBG("wf: thread stopped\n");
 125
 126         return 0;
 127 }
 128
 129 static void wf_start_thread(void)
 130 {
 131         wf_thread = kthread_run(wf_thread_func, NULL, "kwindfarm");
 132         if (IS_ERR(wf_thread)) {
 133                 printk(KERN_ERR "windfarm: failed to create thread,err %ld\n",
 134                        PTR_ERR(wf_thread));
 135                 wf_thread = NULL;
 136         }
 137 }
 138
 139
 140 static void wf_stop_thread(void)
 141 {
 142         if (wf_thread)
 143                 kthread_stop(wf_thread);
 144         wf_thread = NULL;
 145 }
 146
 147 /*
 148  * Controls
 149  */
 150
 151 static void wf_control_release(struct kref *kref)
 152 {
 153         struct wf_control *ct = container_of(kref, struct wf_control, ref);
 154
 155         DBG("wf: Deleting control %s\n", ct->name);
 156
 157         if (ct->ops && ct->ops->release)
 158                 ct->ops->release(ct);
 159         else
 160                 kfree(ct);
 161 }
 162
 163 static ssize_t wf_show_control(struct device *dev,
 164                                struct device_attribute *attr, char *buf)
 165 {
 166         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
 167         s32 val = 0;
 168         int err;
 169
 170         err = ctrl->ops->get_value(ctrl, &val);
 171         if (err < 0)
 172                 return err;
 173         return sprintf(buf, "%d\n", val);
 174 }
 175
 176 /* This is really only for debugging... */
 177 static ssize_t wf_store_control(struct device *dev,
 178                                 struct device_attribute *attr,
 179                                 const char *buf, size_t count)
 180 {
 181         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
 182         int val;
 183         int err;
 184         char *endp;
 185
 186         val = simple_strtoul(buf, &endp, 0);
 187         while (endp < buf + count && (*endp == ' ' || *endp == '\n'))
 188                 ++endp;
 189         if (endp - buf < count)
 190                 return -EINVAL;
 191         err = ctrl->ops->set_value(ctrl, val);
 192         if (err < 0)
 193                 return err;
 194         return count;
 195 }
 196
 197 int wf_register_control(struct wf_control *new_ct)
 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, new_ct->name)) {
 204                         printk(KERN_WARNING "windfarm: trying to register"
 205                                " duplicate control %s\n", ct->name);
 206                         mutex_unlock(&wf_lock);
 207                         return -EEXIST;
 208                 }
 209         }
 210         kref_init(&new_ct->ref);
 211         list_add(&new_ct->link, &wf_controls);
 212
 213         new_ct->attr.attr.name = new_ct->name;
 214         new_ct->attr.attr.mode = 0644;
 215         new_ct->attr.show = wf_show_control;
 216         new_ct->attr.store = wf_store_control;
 217         if (device_create_file(&wf_platform_device.dev, &new_ct->attr))
 218                 printk(KERN_WARNING "windfarm: device_create_file failed"
 219                         " for %s\n", new_ct->name);
 220                 /* the subsystem still does useful work without the file */
 221
 222         DBG("wf: Registered control %s\n", new_ct->name);
 223
 224         wf_notify(WF_EVENT_NEW_CONTROL, new_ct);
 225         mutex_unlock(&wf_lock);
 226
 227         return 0;
 228 }
 229 EXPORT_SYMBOL_GPL(wf_register_control);
 230
 231 void wf_unregister_control(struct wf_control *ct)
 232 {
 233         mutex_lock(&wf_lock);
 234         list_del(&ct->link);
 235         mutex_unlock(&wf_lock);
 236
 237         DBG("wf: Unregistered control %s\n", ct->name);
 238
 239         kref_put(&ct->ref, wf_control_release);
 240 }
 241 EXPORT_SYMBOL_GPL(wf_unregister_control);
 242
 243 struct wf_control * wf_find_control(const char *name)
 244 {
 245         struct wf_control *ct;
 246
 247         mutex_lock(&wf_lock);
 248         list_for_each_entry(ct, &wf_controls, link) {
 249                 if (!strcmp(ct->name, name)) {
 250                         if (wf_get_control(ct))
 251                                 ct = NULL;
 252                         mutex_unlock(&wf_lock);
 253                         return ct;
 254                 }
 255         }
 256         mutex_unlock(&wf_lock);
 257         return NULL;
 258 }
 259 EXPORT_SYMBOL_GPL(wf_find_control);
 260
 261 int wf_get_control(struct wf_control *ct)
 262 {
 263         if (!try_module_get(ct->ops->owner))
 264                 return -ENODEV;
 265         kref_get(&ct->ref);
 266         return 0;
 267 }
 268 EXPORT_SYMBOL_GPL(wf_get_control);
 269
 270 void wf_put_control(struct wf_control *ct)
 271 {
 272         struct module *mod = ct->ops->owner;
 273         kref_put(&ct->ref, wf_control_release);
 274         module_put(mod);
 275 }
 276 EXPORT_SYMBOL_GPL(wf_put_control);
 277
 278
 279 /*
 280  * Sensors
 281  */
 282
 283
 284 static void wf_sensor_release(struct kref *kref)
 285 {
 286         struct wf_sensor *sr = container_of(kref, struct wf_sensor, ref);
 287
 288         DBG("wf: Deleting sensor %s\n", sr->name);
 289
 290         if (sr->ops && sr->ops->release)
 291                 sr->ops->release(sr);
 292         else
 293                 kfree(sr);
 294 }
 295
 296 static ssize_t wf_show_sensor(struct device *dev,
 297                               struct device_attribute *attr, char *buf)
 298 {
 299         struct wf_sensor *sens = container_of(attr, struct wf_sensor, attr);
 300         s32 val = 0;
 301         int err;
 302
 303         err = sens->ops->get_value(sens, &val);
 304         if (err < 0)
 305                 return err;
 306         return sprintf(buf, "%d.%03d\n", FIX32TOPRINT(val));
 307 }
 308
 309 int wf_register_sensor(struct wf_sensor *new_sr)
 310 {
 311         struct wf_sensor *sr;
 312
 313         mutex_lock(&wf_lock);
 314         list_for_each_entry(sr, &wf_sensors, link) {
 315                 if (!strcmp(sr->name, new_sr->name)) {
 316                         printk(KERN_WARNING "windfarm: trying to register"
 317                                " duplicate sensor %s\n", sr->name);
 318                         mutex_unlock(&wf_lock);
 319                         return -EEXIST;
 320                 }
 321         }
 322         kref_init(&new_sr->ref);
 323         list_add(&new_sr->link, &wf_sensors);
 324
 325         sysfs_attr_init(&new_sr->attr.attr);
 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 (of_machine_is_compatible("PowerMac7,2") ||
 474             of_machine_is_compatible("PowerMac7,3") ||
 475             of_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