drivers/macintosh/windfarm_core.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Windfarm PowerMac thermal control. Core
   4  *
   5  * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
   6  *                    <benh@kernel.crashing.org>
   7  *
   8  * This core code tracks the list of sensors & controls, register
   9  * clients, and holds the kernel thread used for control.
  10  *
  11  * TODO:
  12  *
  13  * Add some information about sensor/control type and data format to
  14  * sensors/controls, and have the sysfs attribute stuff be moved
  15  * generically here instead of hard coded in the platform specific
  16  * driver as it us currently
  17  *
  18  * This however requires solving some annoying lifetime issues with
  19  * sysfs which doesn't seem to have lifetime rules for struct attribute,
  20  * I may have to create full features kobjects for every sensor/control
  21  * instead which is a bit of an overkill imho
  22  */
  23
  24 #include <linux/types.h>
  25 #include <linux/errno.h>
  26 #include <linux/kernel.h>
  27 #include <linux/slab.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 static int wf_critical_overtemp(void)
  75 {
  76         static char const critical_overtemp_path[] = "/sbin/critical_overtemp";
  77         char *argv[] = { (char *)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
  87 static int wf_thread_func(void *data)
  88 {
  89         unsigned long next, delay;
  90
  91         next = jiffies;
  92
  93         DBG("wf: thread started\n");
  94
  95         set_freezable();
  96         while (!kthread_should_stop()) {
  97                 try_to_freeze();
  98
  99                 if (time_after_eq(jiffies, next)) {
 100                         wf_notify(WF_EVENT_TICK, NULL);
 101                         if (wf_overtemp) {
 102                                 wf_overtemp_counter++;
 103                                 /* 10 seconds overtemp, notify userland */
 104                                 if (wf_overtemp_counter > 10)
 105                                         wf_critical_overtemp();
 106                                 /* 30 seconds, shutdown */
 107                                 if (wf_overtemp_counter > 30) {
 108                                         printk(KERN_ERR "windfarm: Overtemp "
 109                                                "for more than 30"
 110                                                " seconds, shutting down\n");
 111                                         machine_power_off();
 112                                 }
 113                         }
 114                         next += HZ;
 115                 }
 116
 117                 delay = next - jiffies;
 118                 if (delay <= HZ)
 119                         schedule_timeout_interruptible(delay);
 120         }
 121
 122         DBG("wf: thread stopped\n");
 123
 124         return 0;
 125 }
 126
 127 static void wf_start_thread(void)
 128 {
 129         wf_thread = kthread_run(wf_thread_func, NULL, "kwindfarm");
 130         if (IS_ERR(wf_thread)) {
 131                 printk(KERN_ERR "windfarm: failed to create thread,err %ld\n",
 132                        PTR_ERR(wf_thread));
 133                 wf_thread = NULL;
 134         }
 135 }
 136
 137
 138 static void wf_stop_thread(void)
 139 {
 140         if (wf_thread)
 141                 kthread_stop(wf_thread);
 142         wf_thread = NULL;
 143 }
 144
 145 /*
 146  * Controls
 147  */
 148
 149 static void wf_control_release(struct kref *kref)
 150 {
 151         struct wf_control *ct = container_of(kref, struct wf_control, ref);
 152
 153         DBG("wf: Deleting control %s\n", ct->name);
 154
 155         if (ct->ops && ct->ops->release)
 156                 ct->ops->release(ct);
 157         else
 158                 kfree(ct);
 159 }
 160
 161 static ssize_t wf_show_control(struct device *dev,
 162                                struct device_attribute *attr, char *buf)
 163 {
 164         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
 165         const char *typestr;
 166         s32 val = 0;
 167         int err;
 168
 169         err = ctrl->ops->get_value(ctrl, &val);
 170         if (err < 0) {
 171                 if (err == -EFAULT)
 172                         return sprintf(buf, "<HW FAULT>\n");
 173                 return err;
 174         }
 175         switch(ctrl->type) {
 176         case WF_CONTROL_RPM_FAN:
 177                 typestr = " RPM";
 178                 break;
 179         case WF_CONTROL_PWM_FAN:
 180                 typestr = " %";
 181                 break;
 182         default:
 183                 typestr = "";
 184         }
 185         return sprintf(buf, "%d%s\n", val, typestr);
 186 }
 187
 188 /* This is really only for debugging... */
 189 static ssize_t wf_store_control(struct device *dev,
 190                                 struct device_attribute *attr,
 191                                 const char *buf, size_t count)
 192 {
 193         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
 194         int val;
 195         int err;
 196         char *endp;
 197
 198         val = simple_strtoul(buf, &endp, 0);
 199         while (endp < buf + count && (*endp == ' ' || *endp == '\n'))
 200                 ++endp;
 201         if (endp - buf < count)
 202                 return -EINVAL;
 203         err = ctrl->ops->set_value(ctrl, val);
 204         if (err < 0)
 205                 return err;
 206         return count;
 207 }
 208
 209 int wf_register_control(struct wf_control *new_ct)
 210 {
 211         struct wf_control *ct;
 212
 213         mutex_lock(&wf_lock);
 214         list_for_each_entry(ct, &wf_controls, link) {
 215                 if (!strcmp(ct->name, new_ct->name)) {
 216                         printk(KERN_WARNING "windfarm: trying to register"
 217                                " duplicate control %s\n", ct->name);
 218                         mutex_unlock(&wf_lock);
 219                         return -EEXIST;
 220                 }
 221         }
 222         kref_init(&new_ct->ref);
 223         list_add(&new_ct->link, &wf_controls);
 224
 225         sysfs_attr_init(&new_ct->attr.attr);
 226         new_ct->attr.attr.name = new_ct->name;
 227         new_ct->attr.attr.mode = 0644;
 228         new_ct->attr.show = wf_show_control;
 229         new_ct->attr.store = wf_store_control;
 230         if (device_create_file(&wf_platform_device.dev, &new_ct->attr))
 231                 printk(KERN_WARNING "windfarm: device_create_file failed"
 232                         " for %s\n", new_ct->name);
 233                 /* the subsystem still does useful work without the file */
 234
 235         DBG("wf: Registered control %s\n", new_ct->name);
 236
 237         wf_notify(WF_EVENT_NEW_CONTROL, new_ct);
 238         mutex_unlock(&wf_lock);
 239
 240         return 0;
 241 }
 242 EXPORT_SYMBOL_GPL(wf_register_control);
 243
 244 void wf_unregister_control(struct wf_control *ct)
 245 {
 246         mutex_lock(&wf_lock);
 247         list_del(&ct->link);
 248         mutex_unlock(&wf_lock);
 249
 250         DBG("wf: Unregistered control %s\n", ct->name);
 251
 252         kref_put(&ct->ref, wf_control_release);
 253 }
 254 EXPORT_SYMBOL_GPL(wf_unregister_control);
 255
 256 int wf_get_control(struct wf_control *ct)
 257 {
 258         if (!try_module_get(ct->ops->owner))
 259                 return -ENODEV;
 260         kref_get(&ct->ref);
 261         return 0;
 262 }
 263 EXPORT_SYMBOL_GPL(wf_get_control);
 264
 265 void wf_put_control(struct wf_control *ct)
 266 {
 267         struct module *mod = ct->ops->owner;
 268         kref_put(&ct->ref, wf_control_release);
 269         module_put(mod);
 270 }
 271 EXPORT_SYMBOL_GPL(wf_put_control);
 272
 273
 274 /*
 275  * Sensors
 276  */
 277
 278
 279 static void wf_sensor_release(struct kref *kref)
 280 {
 281         struct wf_sensor *sr = container_of(kref, struct wf_sensor, ref);
 282
 283         DBG("wf: Deleting sensor %s\n", sr->name);
 284
 285         if (sr->ops && sr->ops->release)
 286                 sr->ops->release(sr);
 287         else
 288                 kfree(sr);
 289 }
 290
 291 static ssize_t wf_show_sensor(struct device *dev,
 292                               struct device_attribute *attr, char *buf)
 293 {
 294         struct wf_sensor *sens = container_of(attr, struct wf_sensor, attr);
 295         s32 val = 0;
 296         int err;
 297
 298         err = sens->ops->get_value(sens, &val);
 299         if (err < 0)
 300                 return err;
 301         return sprintf(buf, "%d.%03d\n", FIX32TOPRINT(val));
 302 }
 303
 304 int wf_register_sensor(struct wf_sensor *new_sr)
 305 {
 306         struct wf_sensor *sr;
 307
 308         mutex_lock(&wf_lock);
 309         list_for_each_entry(sr, &wf_sensors, link) {
 310                 if (!strcmp(sr->name, new_sr->name)) {
 311                         printk(KERN_WARNING "windfarm: trying to register"
 312                                " duplicate sensor %s\n", sr->name);
 313                         mutex_unlock(&wf_lock);
 314                         return -EEXIST;
 315                 }
 316         }
 317         kref_init(&new_sr->ref);
 318         list_add(&new_sr->link, &wf_sensors);
 319
 320         sysfs_attr_init(&new_sr->attr.attr);
 321         new_sr->attr.attr.name = new_sr->name;
 322         new_sr->attr.attr.mode = 0444;
 323         new_sr->attr.show = wf_show_sensor;
 324         new_sr->attr.store = NULL;
 325         if (device_create_file(&wf_platform_device.dev, &new_sr->attr))
 326                 printk(KERN_WARNING "windfarm: device_create_file failed"
 327                         " for %s\n", new_sr->name);
 328                 /* the subsystem still does useful work without the file */
 329
 330         DBG("wf: Registered sensor %s\n", new_sr->name);
 331
 332         wf_notify(WF_EVENT_NEW_SENSOR, new_sr);
 333         mutex_unlock(&wf_lock);
 334
 335         return 0;
 336 }
 337 EXPORT_SYMBOL_GPL(wf_register_sensor);
 338
 339 void wf_unregister_sensor(struct wf_sensor *sr)
 340 {
 341         mutex_lock(&wf_lock);
 342         list_del(&sr->link);
 343         mutex_unlock(&wf_lock);
 344
 345         DBG("wf: Unregistered sensor %s\n", sr->name);
 346
 347         wf_put_sensor(sr);
 348 }
 349 EXPORT_SYMBOL_GPL(wf_unregister_sensor);
 350
 351 int wf_get_sensor(struct wf_sensor *sr)
 352 {
 353         if (!try_module_get(sr->ops->owner))
 354                 return -ENODEV;
 355         kref_get(&sr->ref);
 356         return 0;
 357 }
 358 EXPORT_SYMBOL_GPL(wf_get_sensor);
 359
 360 void wf_put_sensor(struct wf_sensor *sr)
 361 {
 362         struct module *mod = sr->ops->owner;
 363         kref_put(&sr->ref, wf_sensor_release);
 364         module_put(mod);
 365 }
 366 EXPORT_SYMBOL_GPL(wf_put_sensor);
 367
 368
 369 /*
 370  * Client & notification
 371  */
 372
 373 int wf_register_client(struct notifier_block *nb)
 374 {
 375         int rc;
 376         struct wf_control *ct;
 377         struct wf_sensor *sr;
 378
 379         mutex_lock(&wf_lock);
 380         rc = blocking_notifier_chain_register(&wf_client_list, nb);
 381         if (rc != 0)
 382                 goto bail;
 383         wf_client_count++;
 384         list_for_each_entry(ct, &wf_controls, link)
 385                 wf_notify(WF_EVENT_NEW_CONTROL, ct);
 386         list_for_each_entry(sr, &wf_sensors, link)
 387                 wf_notify(WF_EVENT_NEW_SENSOR, sr);
 388         if (wf_client_count == 1)
 389                 wf_start_thread();
 390  bail:
 391         mutex_unlock(&wf_lock);
 392         return rc;
 393 }
 394 EXPORT_SYMBOL_GPL(wf_register_client);
 395
 396 int wf_unregister_client(struct notifier_block *nb)
 397 {
 398         mutex_lock(&wf_lock);
 399         blocking_notifier_chain_unregister(&wf_client_list, nb);
 400         wf_client_count--;
 401         if (wf_client_count == 0)
 402                 wf_stop_thread();
 403         mutex_unlock(&wf_lock);
 404
 405         return 0;
 406 }
 407 EXPORT_SYMBOL_GPL(wf_unregister_client);
 408
 409 void wf_set_overtemp(void)
 410 {
 411         mutex_lock(&wf_lock);
 412         wf_overtemp++;
 413         if (wf_overtemp == 1) {
 414                 printk(KERN_WARNING "windfarm: Overtemp condition detected !\n");
 415                 wf_overtemp_counter = 0;
 416                 wf_notify(WF_EVENT_OVERTEMP, NULL);
 417         }
 418         mutex_unlock(&wf_lock);
 419 }
 420 EXPORT_SYMBOL_GPL(wf_set_overtemp);
 421
 422 void wf_clear_overtemp(void)
 423 {
 424         mutex_lock(&wf_lock);
 425         WARN_ON(wf_overtemp == 0);
 426         if (wf_overtemp == 0) {
 427                 mutex_unlock(&wf_lock);
 428                 return;
 429         }
 430         wf_overtemp--;
 431         if (wf_overtemp == 0) {
 432                 printk(KERN_WARNING "windfarm: Overtemp condition cleared !\n");
 433                 wf_notify(WF_EVENT_NORMALTEMP, NULL);
 434         }
 435         mutex_unlock(&wf_lock);
 436 }
 437 EXPORT_SYMBOL_GPL(wf_clear_overtemp);
 438
 439 static int __init windfarm_core_init(void)
 440 {
 441         DBG("wf: core loaded\n");
 442
 443         platform_device_register(&wf_platform_device);
 444         return 0;
 445 }
 446
 447 static void __exit windfarm_core_exit(void)
 448 {
 449         BUG_ON(wf_client_count != 0);
 450
 451         DBG("wf: core unloaded\n");
 452
 453         platform_device_unregister(&wf_platform_device);
 454 }
 455
 456
 457 module_init(windfarm_core_init);
 458 module_exit(windfarm_core_exit);
 459
 460 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 461 MODULE_DESCRIPTION("Core component of PowerMac thermal control");
 462 MODULE_LICENSE("GPL");
 463