drm/i915: disable ppgtt on snb when dmar is enabled
[linux-2.6.git] / drivers / char / apm-emulation.c
1 /*
2  * bios-less APM driver for ARM Linux
3  *  Jamey Hicks <jamey@crl.dec.com>
4  *  adapted from the APM BIOS driver for Linux by Stephen Rothwell (sfr@linuxcare.com)
5  *
6  * APM 1.2 Reference:
7  *   Intel Corporation, Microsoft Corporation. Advanced Power Management
8  *   (APM) BIOS Interface Specification, Revision 1.2, February 1996.
9  *
10  * This document is available from Microsoft at:
11  *    http://www.microsoft.com/whdc/archive/amp_12.mspx
12  */
13 #include <linux/module.h>
14 #include <linux/poll.h>
15 #include <linux/slab.h>
16 #include <linux/mutex.h>
17 #include <linux/proc_fs.h>
18 #include <linux/seq_file.h>
19 #include <linux/miscdevice.h>
20 #include <linux/apm_bios.h>
21 #include <linux/capability.h>
22 #include <linux/sched.h>
23 #include <linux/suspend.h>
24 #include <linux/apm-emulation.h>
25 #include <linux/freezer.h>
26 #include <linux/device.h>
27 #include <linux/kernel.h>
28 #include <linux/list.h>
29 #include <linux/init.h>
30 #include <linux/completion.h>
31 #include <linux/kthread.h>
32 #include <linux/delay.h>
33
34
35 /*
36  * The apm_bios device is one of the misc char devices.
37  * This is its minor number.
38  */
39 #define APM_MINOR_DEV   134
40
41 /*
42  * One option can be changed at boot time as follows:
43  *      apm=on/off                      enable/disable APM
44  */
45
46 /*
47  * Maximum number of events stored
48  */
49 #define APM_MAX_EVENTS          16
50
51 struct apm_queue {
52         unsigned int            event_head;
53         unsigned int            event_tail;
54         apm_event_t             events[APM_MAX_EVENTS];
55 };
56
57 /*
58  * thread states (for threads using a writable /dev/apm_bios fd):
59  *
60  * SUSPEND_NONE:        nothing happening
61  * SUSPEND_PENDING:     suspend event queued for thread and pending to be read
62  * SUSPEND_READ:        suspend event read, pending acknowledgement
63  * SUSPEND_ACKED:       acknowledgement received from thread (via ioctl),
64  *                      waiting for resume
65  * SUSPEND_ACKTO:       acknowledgement timeout
66  * SUSPEND_DONE:        thread had acked suspend and is now notified of
67  *                      resume
68  *
69  * SUSPEND_WAIT:        this thread invoked suspend and is waiting for resume
70  *
71  * A thread migrates in one of three paths:
72  *      NONE -1-> PENDING -2-> READ -3-> ACKED -4-> DONE -5-> NONE
73  *                                  -6-> ACKTO -7-> NONE
74  *      NONE -8-> WAIT -9-> NONE
75  *
76  * While in PENDING or READ, the thread is accounted for in the
77  * suspend_acks_pending counter.
78  *
79  * The transitions are invoked as follows:
80  *      1: suspend event is signalled from the core PM code
81  *      2: the suspend event is read from the fd by the userspace thread
82  *      3: userspace thread issues the APM_IOC_SUSPEND ioctl (as ack)
83  *      4: core PM code signals that we have resumed
84  *      5: APM_IOC_SUSPEND ioctl returns
85  *
86  *      6: the notifier invoked from the core PM code timed out waiting
87  *         for all relevant threds to enter ACKED state and puts those
88  *         that haven't into ACKTO
89  *      7: those threads issue APM_IOC_SUSPEND ioctl too late,
90  *         get an error
91  *
92  *      8: userspace thread issues the APM_IOC_SUSPEND ioctl (to suspend),
93  *         ioctl code invokes pm_suspend()
94  *      9: pm_suspend() returns indicating resume
95  */
96 enum apm_suspend_state {
97         SUSPEND_NONE,
98         SUSPEND_PENDING,
99         SUSPEND_READ,
100         SUSPEND_ACKED,
101         SUSPEND_ACKTO,
102         SUSPEND_WAIT,
103         SUSPEND_DONE,
104 };
105
106 /*
107  * The per-file APM data
108  */
109 struct apm_user {
110         struct list_head        list;
111
112         unsigned int            suser: 1;
113         unsigned int            writer: 1;
114         unsigned int            reader: 1;
115
116         int                     suspend_result;
117         enum apm_suspend_state  suspend_state;
118
119         struct apm_queue        queue;
120 };
121
122 /*
123  * Local variables
124  */
125 static atomic_t suspend_acks_pending = ATOMIC_INIT(0);
126 static atomic_t userspace_notification_inhibit = ATOMIC_INIT(0);
127 static int apm_disabled;
128 static struct task_struct *kapmd_tsk;
129
130 static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
131 static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
132
133 /*
134  * This is a list of everyone who has opened /dev/apm_bios
135  */
136 static DECLARE_RWSEM(user_list_lock);
137 static LIST_HEAD(apm_user_list);
138
139 /*
140  * kapmd info.  kapmd provides us a process context to handle
141  * "APM" events within - specifically necessary if we're going
142  * to be suspending the system.
143  */
144 static DECLARE_WAIT_QUEUE_HEAD(kapmd_wait);
145 static DEFINE_SPINLOCK(kapmd_queue_lock);
146 static struct apm_queue kapmd_queue;
147
148 static DEFINE_MUTEX(state_lock);
149
150 static const char driver_version[] = "1.13";    /* no spaces */
151
152
153
154 /*
155  * Compatibility cruft until the IPAQ people move over to the new
156  * interface.
157  */
158 static void __apm_get_power_status(struct apm_power_info *info)
159 {
160 }
161
162 /*
163  * This allows machines to provide their own "apm get power status" function.
164  */
165 void (*apm_get_power_status)(struct apm_power_info *) = __apm_get_power_status;
166 EXPORT_SYMBOL(apm_get_power_status);
167
168
169 /*
170  * APM event queue management.
171  */
172 static inline int queue_empty(struct apm_queue *q)
173 {
174         return q->event_head == q->event_tail;
175 }
176
177 static inline apm_event_t queue_get_event(struct apm_queue *q)
178 {
179         q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS;
180         return q->events[q->event_tail];
181 }
182
183 static void queue_add_event(struct apm_queue *q, apm_event_t event)
184 {
185         q->event_head = (q->event_head + 1) % APM_MAX_EVENTS;
186         if (q->event_head == q->event_tail) {
187                 static int notified;
188
189                 if (notified++ == 0)
190                     printk(KERN_ERR "apm: an event queue overflowed\n");
191                 q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS;
192         }
193         q->events[q->event_head] = event;
194 }
195
196 static void queue_event(apm_event_t event)
197 {
198         struct apm_user *as;
199
200         down_read(&user_list_lock);
201         list_for_each_entry(as, &apm_user_list, list) {
202                 if (as->reader)
203                         queue_add_event(&as->queue, event);
204         }
205         up_read(&user_list_lock);
206         wake_up_interruptible(&apm_waitqueue);
207 }
208
209 static ssize_t apm_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos)
210 {
211         struct apm_user *as = fp->private_data;
212         apm_event_t event;
213         int i = count, ret = 0;
214
215         if (count < sizeof(apm_event_t))
216                 return -EINVAL;
217
218         if (queue_empty(&as->queue) && fp->f_flags & O_NONBLOCK)
219                 return -EAGAIN;
220
221         wait_event_interruptible(apm_waitqueue, !queue_empty(&as->queue));
222
223         while ((i >= sizeof(event)) && !queue_empty(&as->queue)) {
224                 event = queue_get_event(&as->queue);
225
226                 ret = -EFAULT;
227                 if (copy_to_user(buf, &event, sizeof(event)))
228                         break;
229
230                 mutex_lock(&state_lock);
231                 if (as->suspend_state == SUSPEND_PENDING &&
232                     (event == APM_SYS_SUSPEND || event == APM_USER_SUSPEND))
233                         as->suspend_state = SUSPEND_READ;
234                 mutex_unlock(&state_lock);
235
236                 buf += sizeof(event);
237                 i -= sizeof(event);
238         }
239
240         if (i < count)
241                 ret = count - i;
242
243         return ret;
244 }
245
246 static unsigned int apm_poll(struct file *fp, poll_table * wait)
247 {
248         struct apm_user *as = fp->private_data;
249
250         poll_wait(fp, &apm_waitqueue, wait);
251         return queue_empty(&as->queue) ? 0 : POLLIN | POLLRDNORM;
252 }
253
254 /*
255  * apm_ioctl - handle APM ioctl
256  *
257  * APM_IOC_SUSPEND
258  *   This IOCTL is overloaded, and performs two functions.  It is used to:
259  *     - initiate a suspend
260  *     - acknowledge a suspend read from /dev/apm_bios.
261  *   Only when everyone who has opened /dev/apm_bios with write permission
262  *   has acknowledge does the actual suspend happen.
263  */
264 static long
265 apm_ioctl(struct file *filp, u_int cmd, u_long arg)
266 {
267         struct apm_user *as = filp->private_data;
268         int err = -EINVAL;
269
270         if (!as->suser || !as->writer)
271                 return -EPERM;
272
273         switch (cmd) {
274         case APM_IOC_SUSPEND:
275                 mutex_lock(&state_lock);
276
277                 as->suspend_result = -EINTR;
278
279                 switch (as->suspend_state) {
280                 case SUSPEND_READ:
281                         /*
282                          * If we read a suspend command from /dev/apm_bios,
283                          * then the corresponding APM_IOC_SUSPEND ioctl is
284                          * interpreted as an acknowledge.
285                          */
286                         as->suspend_state = SUSPEND_ACKED;
287                         atomic_dec(&suspend_acks_pending);
288                         mutex_unlock(&state_lock);
289
290                         /*
291                          * suspend_acks_pending changed, the notifier needs to
292                          * be woken up for this
293                          */
294                         wake_up(&apm_suspend_waitqueue);
295
296                         /*
297                          * Wait for the suspend/resume to complete.  If there
298                          * are pending acknowledges, we wait here for them.
299                          * wait_event_freezable() is interruptible and pending
300                          * signal can cause busy looping.  We aren't doing
301                          * anything critical, chill a bit on each iteration.
302                          */
303                         while (wait_event_freezable(apm_suspend_waitqueue,
304                                         as->suspend_state == SUSPEND_DONE))
305                                 msleep(10);
306                         break;
307                 case SUSPEND_ACKTO:
308                         as->suspend_result = -ETIMEDOUT;
309                         mutex_unlock(&state_lock);
310                         break;
311                 default:
312                         as->suspend_state = SUSPEND_WAIT;
313                         mutex_unlock(&state_lock);
314
315                         /*
316                          * Otherwise it is a request to suspend the system.
317                          * Just invoke pm_suspend(), we'll handle it from
318                          * there via the notifier.
319                          */
320                         as->suspend_result = pm_suspend(PM_SUSPEND_MEM);
321                 }
322
323                 mutex_lock(&state_lock);
324                 err = as->suspend_result;
325                 as->suspend_state = SUSPEND_NONE;
326                 mutex_unlock(&state_lock);
327                 break;
328         }
329
330         return err;
331 }
332
333 static int apm_release(struct inode * inode, struct file * filp)
334 {
335         struct apm_user *as = filp->private_data;
336
337         filp->private_data = NULL;
338
339         down_write(&user_list_lock);
340         list_del(&as->list);
341         up_write(&user_list_lock);
342
343         /*
344          * We are now unhooked from the chain.  As far as new
345          * events are concerned, we no longer exist.
346          */
347         mutex_lock(&state_lock);
348         if (as->suspend_state == SUSPEND_PENDING ||
349             as->suspend_state == SUSPEND_READ)
350                 atomic_dec(&suspend_acks_pending);
351         mutex_unlock(&state_lock);
352
353         wake_up(&apm_suspend_waitqueue);
354
355         kfree(as);
356         return 0;
357 }
358
359 static int apm_open(struct inode * inode, struct file * filp)
360 {
361         struct apm_user *as;
362
363         as = kzalloc(sizeof(*as), GFP_KERNEL);
364         if (as) {
365                 /*
366                  * XXX - this is a tiny bit broken, when we consider BSD
367                  * process accounting. If the device is opened by root, we
368                  * instantly flag that we used superuser privs. Who knows,
369                  * we might close the device immediately without doing a
370                  * privileged operation -- cevans
371                  */
372                 as->suser = capable(CAP_SYS_ADMIN);
373                 as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
374                 as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
375
376                 down_write(&user_list_lock);
377                 list_add(&as->list, &apm_user_list);
378                 up_write(&user_list_lock);
379
380                 filp->private_data = as;
381         }
382
383         return as ? 0 : -ENOMEM;
384 }
385
386 static const struct file_operations apm_bios_fops = {
387         .owner          = THIS_MODULE,
388         .read           = apm_read,
389         .poll           = apm_poll,
390         .unlocked_ioctl = apm_ioctl,
391         .open           = apm_open,
392         .release        = apm_release,
393         .llseek         = noop_llseek,
394 };
395
396 static struct miscdevice apm_device = {
397         .minor          = APM_MINOR_DEV,
398         .name           = "apm_bios",
399         .fops           = &apm_bios_fops
400 };
401
402
403 #ifdef CONFIG_PROC_FS
404 /*
405  * Arguments, with symbols from linux/apm_bios.h.
406  *
407  *   0) Linux driver version (this will change if format changes)
408  *   1) APM BIOS Version.  Usually 1.0, 1.1 or 1.2.
409  *   2) APM flags from APM Installation Check (0x00):
410  *      bit 0: APM_16_BIT_SUPPORT
411  *      bit 1: APM_32_BIT_SUPPORT
412  *      bit 2: APM_IDLE_SLOWS_CLOCK
413  *      bit 3: APM_BIOS_DISABLED
414  *      bit 4: APM_BIOS_DISENGAGED
415  *   3) AC line status
416  *      0x00: Off-line
417  *      0x01: On-line
418  *      0x02: On backup power (BIOS >= 1.1 only)
419  *      0xff: Unknown
420  *   4) Battery status
421  *      0x00: High
422  *      0x01: Low
423  *      0x02: Critical
424  *      0x03: Charging
425  *      0x04: Selected battery not present (BIOS >= 1.2 only)
426  *      0xff: Unknown
427  *   5) Battery flag
428  *      bit 0: High
429  *      bit 1: Low
430  *      bit 2: Critical
431  *      bit 3: Charging
432  *      bit 7: No system battery
433  *      0xff: Unknown
434  *   6) Remaining battery life (percentage of charge):
435  *      0-100: valid
436  *      -1: Unknown
437  *   7) Remaining battery life (time units):
438  *      Number of remaining minutes or seconds
439  *      -1: Unknown
440  *   8) min = minutes; sec = seconds
441  */
442 static int proc_apm_show(struct seq_file *m, void *v)
443 {
444         struct apm_power_info info;
445         char *units;
446
447         info.ac_line_status = 0xff;
448         info.battery_status = 0xff;
449         info.battery_flag   = 0xff;
450         info.battery_life   = -1;
451         info.time           = -1;
452         info.units          = -1;
453
454         if (apm_get_power_status)
455                 apm_get_power_status(&info);
456
457         switch (info.units) {
458         default:        units = "?";    break;
459         case 0:         units = "min";  break;
460         case 1:         units = "sec";  break;
461         }
462
463         seq_printf(m, "%s 1.2 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
464                      driver_version, APM_32_BIT_SUPPORT,
465                      info.ac_line_status, info.battery_status,
466                      info.battery_flag, info.battery_life,
467                      info.time, units);
468
469         return 0;
470 }
471
472 static int proc_apm_open(struct inode *inode, struct file *file)
473 {
474         return single_open(file, proc_apm_show, NULL);
475 }
476
477 static const struct file_operations apm_proc_fops = {
478         .owner          = THIS_MODULE,
479         .open           = proc_apm_open,
480         .read           = seq_read,
481         .llseek         = seq_lseek,
482         .release        = single_release,
483 };
484 #endif
485
486 static int kapmd(void *arg)
487 {
488         do {
489                 apm_event_t event;
490
491                 wait_event_interruptible(kapmd_wait,
492                                 !queue_empty(&kapmd_queue) || kthread_should_stop());
493
494                 if (kthread_should_stop())
495                         break;
496
497                 spin_lock_irq(&kapmd_queue_lock);
498                 event = 0;
499                 if (!queue_empty(&kapmd_queue))
500                         event = queue_get_event(&kapmd_queue);
501                 spin_unlock_irq(&kapmd_queue_lock);
502
503                 switch (event) {
504                 case 0:
505                         break;
506
507                 case APM_LOW_BATTERY:
508                 case APM_POWER_STATUS_CHANGE:
509                         queue_event(event);
510                         break;
511
512                 case APM_USER_SUSPEND:
513                 case APM_SYS_SUSPEND:
514                         pm_suspend(PM_SUSPEND_MEM);
515                         break;
516
517                 case APM_CRITICAL_SUSPEND:
518                         atomic_inc(&userspace_notification_inhibit);
519                         pm_suspend(PM_SUSPEND_MEM);
520                         atomic_dec(&userspace_notification_inhibit);
521                         break;
522                 }
523         } while (1);
524
525         return 0;
526 }
527
528 static int apm_suspend_notifier(struct notifier_block *nb,
529                                 unsigned long event,
530                                 void *dummy)
531 {
532         struct apm_user *as;
533         int err;
534
535         /* short-cut emergency suspends */
536         if (atomic_read(&userspace_notification_inhibit))
537                 return NOTIFY_DONE;
538
539         switch (event) {
540         case PM_SUSPEND_PREPARE:
541                 /*
542                  * Queue an event to all "writer" users that we want
543                  * to suspend and need their ack.
544                  */
545                 mutex_lock(&state_lock);
546                 down_read(&user_list_lock);
547
548                 list_for_each_entry(as, &apm_user_list, list) {
549                         if (as->suspend_state != SUSPEND_WAIT && as->reader &&
550                             as->writer && as->suser) {
551                                 as->suspend_state = SUSPEND_PENDING;
552                                 atomic_inc(&suspend_acks_pending);
553                                 queue_add_event(&as->queue, APM_USER_SUSPEND);
554                         }
555                 }
556
557                 up_read(&user_list_lock);
558                 mutex_unlock(&state_lock);
559                 wake_up_interruptible(&apm_waitqueue);
560
561                 /*
562                  * Wait for the the suspend_acks_pending variable to drop to
563                  * zero, meaning everybody acked the suspend event (or the
564                  * process was killed.)
565                  *
566                  * If the app won't answer within a short while we assume it
567                  * locked up and ignore it.
568                  */
569                 err = wait_event_interruptible_timeout(
570                         apm_suspend_waitqueue,
571                         atomic_read(&suspend_acks_pending) == 0,
572                         5*HZ);
573
574                 /* timed out */
575                 if (err == 0) {
576                         /*
577                          * Move anybody who timed out to "ack timeout" state.
578                          *
579                          * We could time out and the userspace does the ACK
580                          * right after we time out but before we enter the
581                          * locked section here, but that's fine.
582                          */
583                         mutex_lock(&state_lock);
584                         down_read(&user_list_lock);
585                         list_for_each_entry(as, &apm_user_list, list) {
586                                 if (as->suspend_state == SUSPEND_PENDING ||
587                                     as->suspend_state == SUSPEND_READ) {
588                                         as->suspend_state = SUSPEND_ACKTO;
589                                         atomic_dec(&suspend_acks_pending);
590                                 }
591                         }
592                         up_read(&user_list_lock);
593                         mutex_unlock(&state_lock);
594                 }
595
596                 /* let suspend proceed */
597                 if (err >= 0)
598                         return NOTIFY_OK;
599
600                 /* interrupted by signal */
601                 return notifier_from_errno(err);
602
603         case PM_POST_SUSPEND:
604                 /*
605                  * Anyone on the APM queues will think we're still suspended.
606                  * Send a message so everyone knows we're now awake again.
607                  */
608                 queue_event(APM_NORMAL_RESUME);
609
610                 /*
611                  * Finally, wake up anyone who is sleeping on the suspend.
612                  */
613                 mutex_lock(&state_lock);
614                 down_read(&user_list_lock);
615                 list_for_each_entry(as, &apm_user_list, list) {
616                         if (as->suspend_state == SUSPEND_ACKED) {
617                                 /*
618                                  * TODO: maybe grab error code, needs core
619                                  * changes to push the error to the notifier
620                                  * chain (could use the second parameter if
621                                  * implemented)
622                                  */
623                                 as->suspend_result = 0;
624                                 as->suspend_state = SUSPEND_DONE;
625                         }
626                 }
627                 up_read(&user_list_lock);
628                 mutex_unlock(&state_lock);
629
630                 wake_up(&apm_suspend_waitqueue);
631                 return NOTIFY_OK;
632
633         default:
634                 return NOTIFY_DONE;
635         }
636 }
637
638 static struct notifier_block apm_notif_block = {
639         .notifier_call = apm_suspend_notifier,
640 };
641
642 static int __init apm_init(void)
643 {
644         int ret;
645
646         if (apm_disabled) {
647                 printk(KERN_NOTICE "apm: disabled on user request.\n");
648                 return -ENODEV;
649         }
650
651         kapmd_tsk = kthread_create(kapmd, NULL, "kapmd");
652         if (IS_ERR(kapmd_tsk)) {
653                 ret = PTR_ERR(kapmd_tsk);
654                 kapmd_tsk = NULL;
655                 goto out;
656         }
657         wake_up_process(kapmd_tsk);
658
659 #ifdef CONFIG_PROC_FS
660         proc_create("apm", 0, NULL, &apm_proc_fops);
661 #endif
662
663         ret = misc_register(&apm_device);
664         if (ret)
665                 goto out_stop;
666
667         ret = register_pm_notifier(&apm_notif_block);
668         if (ret)
669                 goto out_unregister;
670
671         return 0;
672
673  out_unregister:
674         misc_deregister(&apm_device);
675  out_stop:
676         remove_proc_entry("apm", NULL);
677         kthread_stop(kapmd_tsk);
678  out:
679         return ret;
680 }
681
682 static void __exit apm_exit(void)
683 {
684         unregister_pm_notifier(&apm_notif_block);
685         misc_deregister(&apm_device);
686         remove_proc_entry("apm", NULL);
687
688         kthread_stop(kapmd_tsk);
689 }
690
691 module_init(apm_init);
692 module_exit(apm_exit);
693
694 MODULE_AUTHOR("Stephen Rothwell");
695 MODULE_DESCRIPTION("Advanced Power Management");
696 MODULE_LICENSE("GPL");
697
698 #ifndef MODULE
699 static int __init apm_setup(char *str)
700 {
701         while ((str != NULL) && (*str != '\0')) {
702                 if (strncmp(str, "off", 3) == 0)
703                         apm_disabled = 1;
704                 if (strncmp(str, "on", 2) == 0)
705                         apm_disabled = 0;
706                 str = strchr(str, ',');
707                 if (str != NULL)
708                         str += strspn(str, ", \t");
709         }
710         return 1;
711 }
712
713 __setup("apm=", apm_setup);
714 #endif
715
716 /**
717  * apm_queue_event - queue an APM event for kapmd
718  * @event: APM event
719  *
720  * Queue an APM event for kapmd to process and ultimately take the
721  * appropriate action.  Only a subset of events are handled:
722  *   %APM_LOW_BATTERY
723  *   %APM_POWER_STATUS_CHANGE
724  *   %APM_USER_SUSPEND
725  *   %APM_SYS_SUSPEND
726  *   %APM_CRITICAL_SUSPEND
727  */
728 void apm_queue_event(apm_event_t event)
729 {
730         unsigned long flags;
731
732         spin_lock_irqsave(&kapmd_queue_lock, flags);
733         queue_add_event(&kapmd_queue, event);
734         spin_unlock_irqrestore(&kapmd_queue_lock, flags);
735
736         wake_up_interruptible(&kapmd_wait);
737 }
738 EXPORT_SYMBOL(apm_queue_event);