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