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 static 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
  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         const char *typestr;
 167         s32 val = 0;
 168         int err;
 169
 170         err = ctrl->ops->get_value(ctrl, &val);
 171         if (err < 0) {
 172                 if (err == -EFAULT)
 173                         return sprintf(buf, "<HW FAULT>\n");
 174                 return err;
 175         }
 176         switch(ctrl->type) {
 177         case WF_CONTROL_RPM_FAN:
 178                 typestr = " RPM";
 179                 break;
 180         case WF_CONTROL_PWM_FAN:
 181                 typestr = " %";
 182                 break;
 183         default:
 184                 typestr = "";
 185         }
 186         return sprintf(buf, "%d%s\n", val, typestr);
 187 }
 188
 189 /* This is really only for debugging... */
 190 static ssize_t wf_store_control(struct device *dev,
 191                                 struct device_attribute *attr,
 192                                 const char *buf, size_t count)
 193 {
 194         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
 195         int val;
 196         int err;
 197         char *endp;
 198
 199         val = simple_strtoul(buf, &endp, 0);
 200         while (endp < buf + count && (*endp == ' ' || *endp == '\n'))
 201                 ++endp;
 202         if (endp - buf < count)
 203                 return -EINVAL;
 204         err = ctrl->ops->set_value(ctrl, val);
 205         if (err < 0)
 206                 return err;
 207         return count;
 208 }
 209
 210 int wf_register_control(struct wf_control *new_ct)
 211 {
 212         struct wf_control *ct;
 213
 214         mutex_lock(&wf_lock);
 215         list_for_each_entry(ct, &wf_controls, link) {
 216                 if (!strcmp(ct->name, new_ct->name)) {
 217                         printk(KERN_WARNING "windfarm: trying to register"
 218                                " duplicate control %s\n", ct->name);
 219                         mutex_unlock(&wf_lock);
 220                         return -EEXIST;
 221                 }
 222         }
 223         kref_init(&new_ct->ref);
 224         list_add(&new_ct->link, &wf_controls);
 225
 226         sysfs_attr_init(&new_ct->attr.attr);
 227         new_ct->attr.attr.name = new_ct->name;
 228         new_ct->attr.attr.mode = 0644;
 229         new_ct->attr.show = wf_show_control;
 230         new_ct->attr.store = wf_store_control;
 231         if (device_create_file(&wf_platform_device.dev, &new_ct->attr))
 232                 printk(KERN_WARNING "windfarm: device_create_file failed"
 233                         " for %s\n", new_ct->name);
 234                 /* the subsystem still does useful work without the file */
 235
 236         DBG("wf: Registered control %s\n", new_ct->name);
 237
 238         wf_notify(WF_EVENT_NEW_CONTROL, new_ct);
 239         mutex_unlock(&wf_lock);
 240
 241         return 0;
 242 }
 243 EXPORT_SYMBOL_GPL(wf_register_control);
 244
 245 void wf_unregister_control(struct wf_control *ct)
 246 {
 247         mutex_lock(&wf_lock);
 248         list_del(&ct->link);
 249         mutex_unlock(&wf_lock);
 250
 251         DBG("wf: Unregistered control %s\n", ct->name);
 252
 253         kref_put(&ct->ref, wf_control_release);
 254 }
 255 EXPORT_SYMBOL_GPL(wf_unregister_control);
 256
 257 int wf_get_control(struct wf_control *ct)
 258 {
 259         if (!try_module_get(ct->ops->owner))
 260                 return -ENODEV;
 261         kref_get(&ct->ref);
 262         return 0;
 263 }
 264 EXPORT_SYMBOL_GPL(wf_get_control);
 265
 266 void wf_put_control(struct wf_control *ct)
 267 {
 268         struct module *mod = ct->ops->owner;
 269         kref_put(&ct->ref, wf_control_release);
 270         module_put(mod);
 271 }
 272 EXPORT_SYMBOL_GPL(wf_put_control);
 273
 274
 275 /*
 276  * Sensors
 277  */
 278
 279
 280 static void wf_sensor_release(struct kref *kref)
 281 {
 282         struct wf_sensor *sr = container_of(kref, struct wf_sensor, ref);
 283
 284         DBG("wf: Deleting sensor %s\n", sr->name);
 285
 286         if (sr->ops && sr->ops->release)
 287                 sr->ops->release(sr);
 288         else
 289                 kfree(sr);
 290 }
 291
 292 static ssize_t wf_show_sensor(struct device *dev,
 293                               struct device_attribute *attr, char *buf)
 294 {
 295         struct wf_sensor *sens = container_of(attr, struct wf_sensor, attr);
 296         s32 val = 0;
 297         int err;
 298
 299         err = sens->ops->get_value(sens, &val);
 300         if (err < 0)
 301                 return err;
 302         return sprintf(buf, "%d.%03d\n", FIX32TOPRINT(val));
 303 }
 304
 305 int wf_register_sensor(struct wf_sensor *new_sr)
 306 {
 307         struct wf_sensor *sr;
 308
 309         mutex_lock(&wf_lock);
 310         list_for_each_entry(sr, &wf_sensors, link) {
 311                 if (!strcmp(sr->name, new_sr->name)) {
 312                         printk(KERN_WARNING "windfarm: trying to register"
 313                                " duplicate sensor %s\n", sr->name);
 314                         mutex_unlock(&wf_lock);
 315                         return -EEXIST;
 316                 }
 317         }
 318         kref_init(&new_sr->ref);
 319         list_add(&new_sr->link, &wf_sensors);
 320
 321         sysfs_attr_init(&new_sr->attr.attr);
 322         new_sr->attr.attr.name = new_sr->name;
 323         new_sr->attr.attr.mode = 0444;
 324         new_sr->attr.show = wf_show_sensor;
 325         new_sr->attr.store = NULL;
 326         if (device_create_file(&wf_platform_device.dev, &new_sr->attr))
 327                 printk(KERN_WARNING "windfarm: device_create_file failed"
 328                         " for %s\n", new_sr->name);
 329                 /* the subsystem still does useful work without the file */
 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 int wf_get_sensor(struct wf_sensor *sr)
 353 {
 354         if (!try_module_get(sr->ops->owner))
 355                 return -ENODEV;
 356         kref_get(&sr->ref);
 357         return 0;
 358 }
 359 EXPORT_SYMBOL_GPL(wf_get_sensor);
 360
 361 void wf_put_sensor(struct wf_sensor *sr)
 362 {
 363         struct module *mod = sr->ops->owner;
 364         kref_put(&sr->ref, wf_sensor_release);
 365         module_put(mod);
 366 }
 367 EXPORT_SYMBOL_GPL(wf_put_sensor);
 368
 369
 370 /*
 371  * Client & notification
 372  */
 373
 374 int wf_register_client(struct notifier_block *nb)
 375 {
 376         int rc;
 377         struct wf_control *ct;
 378         struct wf_sensor *sr;
 379
 380         mutex_lock(&wf_lock);
 381         rc = blocking_notifier_chain_register(&wf_client_list, nb);
 382         if (rc != 0)
 383                 goto bail;
 384         wf_client_count++;
 385         list_for_each_entry(ct, &wf_controls, link)
 386                 wf_notify(WF_EVENT_NEW_CONTROL, ct);
 387         list_for_each_entry(sr, &wf_sensors, link)
 388                 wf_notify(WF_EVENT_NEW_SENSOR, sr);
 389         if (wf_client_count == 1)
 390                 wf_start_thread();
 391  bail:
 392         mutex_unlock(&wf_lock);
 393         return rc;
 394 }
 395 EXPORT_SYMBOL_GPL(wf_register_client);
 396
 397 int wf_unregister_client(struct notifier_block *nb)
 398 {
 399         mutex_lock(&wf_lock);
 400         blocking_notifier_chain_unregister(&wf_client_list, nb);
 401         wf_client_count--;
 402         if (wf_client_count == 0)
 403                 wf_stop_thread();
 404         mutex_unlock(&wf_lock);
 405
 406         return 0;
 407 }
 408 EXPORT_SYMBOL_GPL(wf_unregister_client);
 409
 410 void wf_set_overtemp(void)
 411 {
 412         mutex_lock(&wf_lock);
 413         wf_overtemp++;
 414         if (wf_overtemp == 1) {
 415                 printk(KERN_WARNING "windfarm: Overtemp condition detected !\n");
 416                 wf_overtemp_counter = 0;
 417                 wf_notify(WF_EVENT_OVERTEMP, NULL);
 418         }
 419         mutex_unlock(&wf_lock);
 420 }
 421 EXPORT_SYMBOL_GPL(wf_set_overtemp);
 422
 423 void wf_clear_overtemp(void)
 424 {
 425         mutex_lock(&wf_lock);
 426         WARN_ON(wf_overtemp == 0);
 427         if (wf_overtemp == 0) {
 428                 mutex_unlock(&wf_lock);
 429                 return;
 430         }
 431         wf_overtemp--;
 432         if (wf_overtemp == 0) {
 433                 printk(KERN_WARNING "windfarm: Overtemp condition cleared !\n");
 434                 wf_notify(WF_EVENT_NORMALTEMP, NULL);
 435         }
 436         mutex_unlock(&wf_lock);
 437 }
 438 EXPORT_SYMBOL_GPL(wf_clear_overtemp);
 439
 440 static int __init windfarm_core_init(void)
 441 {
 442         DBG("wf: core loaded\n");
 443
 444         platform_device_register(&wf_platform_device);
 445         return 0;
 446 }
 447
 448 static void __exit windfarm_core_exit(void)
 449 {
 450         BUG_ON(wf_client_count != 0);
 451
 452         DBG("wf: core unloaded\n");
 453
 454         platform_device_unregister(&wf_platform_device);
 455 }
 456
 457
 458 module_init(windfarm_core_init);
 459 module_exit(windfarm_core_exit);
 460
 461 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 462 MODULE_DESCRIPTION("Core component of PowerMac thermal control");
 463 MODULE_LICENSE("GPL");
 464