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         sysfs_attr_init(&new_ct->attr.attr);
 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         sysfs_attr_init(&new_sr->attr.attr);
 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 (of_machine_is_compatible("PowerMac7,2") ||
 475             of_machine_is_compatible("PowerMac7,3") ||
 476             of_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