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/smp_lock.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
  38 #include "windfarm.h"
  39
  40 #define VERSION "0.2"
  41
  42 #undef DEBUG
  43
  44 #ifdef DEBUG
  45 #define DBG(args...)    printk(args)
  46 #else
  47 #define DBG(args...)    do { } while(0)
  48 #endif
  49
  50 static LIST_HEAD(wf_controls);
  51 static LIST_HEAD(wf_sensors);
  52 static DEFINE_MUTEX(wf_lock);
  53 static struct notifier_block *wf_client_list;
  54 static int wf_client_count;
  55 static unsigned int wf_overtemp;
  56 static unsigned int wf_overtemp_counter;
  57 struct task_struct *wf_thread;
  58
  59 static struct platform_device wf_platform_device = {
  60         .name   = "windfarm",
  61 };
  62
  63 /*
  64  * Utilities & tick thread
  65  */
  66
  67 static inline void wf_notify(int event, void *param)
  68 {
  69         notifier_call_chain(&wf_client_list, event, param);
  70 }
  71
  72 int wf_critical_overtemp(void)
  73 {
  74         static char * critical_overtemp_path = "/sbin/critical_overtemp";
  75         char *argv[] = { critical_overtemp_path, NULL };
  76         static char *envp[] = { "HOME=/",
  77                                 "TERM=linux",
  78                                 "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
  79                                 NULL };
  80
  81         return call_usermodehelper(critical_overtemp_path, argv, envp, 0);
  82 }
  83 EXPORT_SYMBOL_GPL(wf_critical_overtemp);
  84
  85 static int wf_thread_func(void *data)
  86 {
  87         unsigned long next, delay;
  88
  89         next = jiffies;
  90
  91         DBG("wf: thread started\n");
  92
  93         while(!kthread_should_stop()) {
  94                 try_to_freeze();
  95
  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 signal, but oh well */
 119                 if (signal_pending(current)) {
 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.owner = THIS_MODULE;
 216         new_ct->attr.attr.mode = 0644;
 217         new_ct->attr.show = wf_show_control;
 218         new_ct->attr.store = wf_store_control;
 219         device_create_file(&wf_platform_device.dev, &new_ct->attr);
 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.owner = THIS_MODULE;
 326         new_sr->attr.attr.mode = 0444;
 327         new_sr->attr.show = wf_show_sensor;
 328         new_sr->attr.store = NULL;
 329         device_create_file(&wf_platform_device.dev, &new_sr->attr);
 330
 331         DBG("wf: Registered sensor %s\n", new_sr->name);
 332
 333         wf_notify(WF_EVENT_NEW_SENSOR, new_sr);
 334         mutex_unlock(&wf_lock);
 335
 336         return 0;
 337 }
 338 EXPORT_SYMBOL_GPL(wf_register_sensor);
 339
 340 void wf_unregister_sensor(struct wf_sensor *sr)
 341 {
 342         mutex_lock(&wf_lock);
 343         list_del(&sr->link);
 344         mutex_unlock(&wf_lock);
 345
 346         DBG("wf: Unregistered sensor %s\n", sr->name);
 347
 348         wf_put_sensor(sr);
 349 }
 350 EXPORT_SYMBOL_GPL(wf_unregister_sensor);
 351
 352 struct wf_sensor * wf_find_sensor(const char *name)
 353 {
 354         struct wf_sensor *sr;
 355
 356         mutex_lock(&wf_lock);
 357         list_for_each_entry(sr, &wf_sensors, link) {
 358                 if (!strcmp(sr->name, name)) {
 359                         if (wf_get_sensor(sr))
 360                                 sr = NULL;
 361                         mutex_unlock(&wf_lock);
 362                         return sr;
 363                 }
 364         }
 365         mutex_unlock(&wf_lock);
 366         return NULL;
 367 }
 368 EXPORT_SYMBOL_GPL(wf_find_sensor);
 369
 370 int wf_get_sensor(struct wf_sensor *sr)
 371 {
 372         if (!try_module_get(sr->ops->owner))
 373                 return -ENODEV;
 374         kref_get(&sr->ref);
 375         return 0;
 376 }
 377 EXPORT_SYMBOL_GPL(wf_get_sensor);
 378
 379 void wf_put_sensor(struct wf_sensor *sr)
 380 {
 381         struct module *mod = sr->ops->owner;
 382         kref_put(&sr->ref, wf_sensor_release);
 383         module_put(mod);
 384 }
 385 EXPORT_SYMBOL_GPL(wf_put_sensor);
 386
 387
 388 /*
 389  * Client & notification
 390  */
 391
 392 int wf_register_client(struct notifier_block *nb)
 393 {
 394         int rc;
 395         struct wf_control *ct;
 396         struct wf_sensor *sr;
 397
 398         mutex_lock(&wf_lock);
 399         rc = notifier_chain_register(&wf_client_list, nb);
 400         if (rc != 0)
 401                 goto bail;
 402         wf_client_count++;
 403         list_for_each_entry(ct, &wf_controls, link)
 404                 wf_notify(WF_EVENT_NEW_CONTROL, ct);
 405         list_for_each_entry(sr, &wf_sensors, link)
 406                 wf_notify(WF_EVENT_NEW_SENSOR, sr);
 407         if (wf_client_count == 1)
 408                 wf_start_thread();
 409  bail:
 410         mutex_unlock(&wf_lock);
 411         return rc;
 412 }
 413 EXPORT_SYMBOL_GPL(wf_register_client);
 414
 415 int wf_unregister_client(struct notifier_block *nb)
 416 {
 417         mutex_lock(&wf_lock);
 418         notifier_chain_unregister(&wf_client_list, nb);
 419         wf_client_count++;
 420         if (wf_client_count == 0)
 421                 wf_stop_thread();
 422         mutex_unlock(&wf_lock);
 423
 424         return 0;
 425 }
 426 EXPORT_SYMBOL_GPL(wf_unregister_client);
 427
 428 void wf_set_overtemp(void)
 429 {
 430         mutex_lock(&wf_lock);
 431         wf_overtemp++;
 432         if (wf_overtemp == 1) {
 433                 printk(KERN_WARNING "windfarm: Overtemp condition detected !\n");
 434                 wf_overtemp_counter = 0;
 435                 wf_notify(WF_EVENT_OVERTEMP, NULL);
 436         }
 437         mutex_unlock(&wf_lock);
 438 }
 439 EXPORT_SYMBOL_GPL(wf_set_overtemp);
 440
 441 void wf_clear_overtemp(void)
 442 {
 443         mutex_lock(&wf_lock);
 444         WARN_ON(wf_overtemp == 0);
 445         if (wf_overtemp == 0) {
 446                 mutex_unlock(&wf_lock);
 447                 return;
 448         }
 449         wf_overtemp--;
 450         if (wf_overtemp == 0) {
 451                 printk(KERN_WARNING "windfarm: Overtemp condition cleared !\n");
 452                 wf_notify(WF_EVENT_NORMALTEMP, NULL);
 453         }
 454         mutex_unlock(&wf_lock);
 455 }
 456 EXPORT_SYMBOL_GPL(wf_clear_overtemp);
 457
 458 int wf_is_overtemp(void)
 459 {
 460         return (wf_overtemp != 0);
 461 }
 462 EXPORT_SYMBOL_GPL(wf_is_overtemp);
 463
 464 static int __init windfarm_core_init(void)
 465 {
 466         DBG("wf: core loaded\n");
 467
 468         platform_device_register(&wf_platform_device);
 469         return 0;
 470 }
 471
 472 static void __exit windfarm_core_exit(void)
 473 {
 474         BUG_ON(wf_client_count != 0);
 475
 476         DBG("wf: core unloaded\n");
 477
 478         platform_device_unregister(&wf_platform_device);
 479 }
 480
 481
 482 module_init(windfarm_core_init);
 483 module_exit(windfarm_core_exit);
 484
 485 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 486 MODULE_DESCRIPTION("Core component of PowerMac thermal control");
 487 MODULE_LICENSE("GPL");
 488