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1/*
2 * vgaarb.c: Implements the VGA arbitration. For details refer to
3 * Documentation/vgaarbiter.txt
4 *
5 *
6 * (C) Copyright 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>
7 * (C) Copyright 2007 Paulo R. Zanoni <przanoni@gmail.com>
8 * (C) Copyright 2007, 2009 Tiago Vignatti <vignatti@freedesktop.org>
9 *
10 * Permission is hereby granted, free of charge, to any person obtaining a
11 * copy of this software and associated documentation files (the "Software"),
12 * to deal in the Software without restriction, including without limitation
13 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
14 * and/or sell copies of the Software, and to permit persons to whom the
15 * Software is furnished to do so, subject to the following conditions:
16 *
17 * The above copyright notice and this permission notice (including the next
18 * paragraph) shall be included in all copies or substantial portions of the
19 * Software.
20 *
21 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
22 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
23 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
24 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
25 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
26 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
27 * DEALINGS
28 * IN THE SOFTWARE.
29 *
30 */
31
32#include <linux/module.h>
33#include <linux/kernel.h>
34#include <linux/pci.h>
35#include <linux/errno.h>
36#include <linux/init.h>
37#include <linux/list.h>
38#include <linux/sched.h>
39#include <linux/wait.h>
40#include <linux/spinlock.h>
41#include <linux/poll.h>
42#include <linux/miscdevice.h>
43#include <linux/slab.h>
44
45#include <linux/uaccess.h>
46
47#include <linux/vgaarb.h>
48
49static void vga_arbiter_notify_clients(void);
50/*
51 * We keep a list of all vga devices in the system to speed
52 * up the various operations of the arbiter
53 */
54struct vga_device {
55 struct list_head list;
56 struct pci_dev *pdev;
57 unsigned int decodes; /* what does it decodes */
58 unsigned int owns; /* what does it owns */
59 unsigned int locks; /* what does it locks */
60 unsigned int io_lock_cnt; /* legacy IO lock count */
61 unsigned int mem_lock_cnt; /* legacy MEM lock count */
62 unsigned int io_norm_cnt; /* normal IO count */
63 unsigned int mem_norm_cnt; /* normal MEM count */
64 bool bridge_has_one_vga;
65 /* allow IRQ enable/disable hook */
66 void *cookie;
67 void (*irq_set_state)(void *cookie, bool enable);
68 unsigned int (*set_vga_decode)(void *cookie, bool decode);
69};
70
71static LIST_HEAD(vga_list);
72static int vga_count, vga_decode_count;
73static bool vga_arbiter_used;
74static DEFINE_SPINLOCK(vga_lock);
75static DECLARE_WAIT_QUEUE_HEAD(vga_wait_queue);
76
77
78static const char *vga_iostate_to_str(unsigned int iostate)
79{
80 /* Ignore VGA_RSRC_IO and VGA_RSRC_MEM */
81 iostate &= VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM;
82 switch (iostate) {
83 case VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM:
84 return "io+mem";
85 case VGA_RSRC_LEGACY_IO:
86 return "io";
87 case VGA_RSRC_LEGACY_MEM:
88 return "mem";
89 }
90 return "none";
91}
92
93static int vga_str_to_iostate(char *buf, int str_size, int *io_state)
94{
95 /* we could in theory hand out locks on IO and mem
96 * separately to userspace but it can cause deadlocks */
97 if (strncmp(buf, "none", 4) == 0) {
98 *io_state = VGA_RSRC_NONE;
99 return 1;
100 }
101
102 /* XXX We're not chekcing the str_size! */
103 if (strncmp(buf, "io+mem", 6) == 0)
104 goto both;
105 else if (strncmp(buf, "io", 2) == 0)
106 goto both;
107 else if (strncmp(buf, "mem", 3) == 0)
108 goto both;
109 return 0;
110both:
111 *io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM;
112 return 1;
113}
114
115#ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE
116/* this is only used a cookie - it should not be dereferenced */
117static struct pci_dev *vga_default;
118#endif
119
120static void vga_arb_device_card_gone(struct pci_dev *pdev);
121
122/* Find somebody in our list */
123static struct vga_device *vgadev_find(struct pci_dev *pdev)
124{
125 struct vga_device *vgadev;
126
127 list_for_each_entry(vgadev, &vga_list, list)
128 if (pdev == vgadev->pdev)
129 return vgadev;
130 return NULL;
131}
132
133/* Returns the default VGA device (vgacon's babe) */
134#ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE
135struct pci_dev *vga_default_device(void)
136{
137 return vga_default;
138}
139
140EXPORT_SYMBOL_GPL(vga_default_device);
141
142void vga_set_default_device(struct pci_dev *pdev)
143{
144 if (vga_default == pdev)
145 return;
146
147 pci_dev_put(vga_default);
148 vga_default = pci_dev_get(pdev);
149}
150#endif
151
152static inline void vga_irq_set_state(struct vga_device *vgadev, bool state)
153{
154 if (vgadev->irq_set_state)
155 vgadev->irq_set_state(vgadev->cookie, state);
156}
157
158
159/* If we don't ever use VGA arb we should avoid
160 turning off anything anywhere due to old X servers getting
161 confused about the boot device not being VGA */
162static void vga_check_first_use(void)
163{
164 /* we should inform all GPUs in the system that
165 * VGA arb has occurred and to try and disable resources
166 * if they can */
167 if (!vga_arbiter_used) {
168 vga_arbiter_used = true;
169 vga_arbiter_notify_clients();
170 }
171}
172
173static struct vga_device *__vga_tryget(struct vga_device *vgadev,
174 unsigned int rsrc)
175{
176 unsigned int wants, legacy_wants, match;
177 struct vga_device *conflict;
178 unsigned int pci_bits;
179 u32 flags = 0;
180
181 /* Account for "normal" resources to lock. If we decode the legacy,
182 * counterpart, we need to request it as well
183 */
184 if ((rsrc & VGA_RSRC_NORMAL_IO) &&
185 (vgadev->decodes & VGA_RSRC_LEGACY_IO))
186 rsrc |= VGA_RSRC_LEGACY_IO;
187 if ((rsrc & VGA_RSRC_NORMAL_MEM) &&
188 (vgadev->decodes & VGA_RSRC_LEGACY_MEM))
189 rsrc |= VGA_RSRC_LEGACY_MEM;
190
191 pr_debug("%s: %d\n", __func__, rsrc);
192 pr_debug("%s: owns: %d\n", __func__, vgadev->owns);
193
194 /* Check what resources we need to acquire */
195 wants = rsrc & ~vgadev->owns;
196
197 /* We already own everything, just mark locked & bye bye */
198 if (wants == 0)
199 goto lock_them;
200
201 /* We don't need to request a legacy resource, we just enable
202 * appropriate decoding and go
203 */
204 legacy_wants = wants & VGA_RSRC_LEGACY_MASK;
205 if (legacy_wants == 0)
206 goto enable_them;
207
208 /* Ok, we don't, let's find out how we need to kick off */
209 list_for_each_entry(conflict, &vga_list, list) {
210 unsigned int lwants = legacy_wants;
211 unsigned int change_bridge = 0;
212
213 /* Don't conflict with myself */
214 if (vgadev == conflict)
215 continue;
216
217 /* Check if the architecture allows a conflict between those
218 * 2 devices or if they are on separate domains
219 */
220 if (!vga_conflicts(vgadev->pdev, conflict->pdev))
221 continue;
222
223 /* We have a possible conflict. before we go further, we must
224 * check if we sit on the same bus as the conflicting device.
225 * if we don't, then we must tie both IO and MEM resources
226 * together since there is only a single bit controlling
227 * VGA forwarding on P2P bridges
228 */
229 if (vgadev->pdev->bus != conflict->pdev->bus) {
230 change_bridge = 1;
231 lwants = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM;
232 }
233
234 /* Check if the guy has a lock on the resource. If he does,
235 * return the conflicting entry
236 */
237 if (conflict->locks & lwants)
238 return conflict;
239
240 /* Ok, now check if he owns the resource we want. We don't need
241 * to check "decodes" since it should be impossible to own
242 * own legacy resources you don't decode unless I have a bug
243 * in this code...
244 */
245 WARN_ON(conflict->owns & ~conflict->decodes);
246 match = lwants & conflict->owns;
247 if (!match)
248 continue;
249
250 /* looks like he doesn't have a lock, we can steal
251 * them from him
252 */
253
254 flags = 0;
255 pci_bits = 0;
256
257 if (!conflict->bridge_has_one_vga) {
258 vga_irq_set_state(conflict, false);
259 flags |= PCI_VGA_STATE_CHANGE_DECODES;
260 if (match & (VGA_RSRC_LEGACY_MEM|VGA_RSRC_NORMAL_MEM))
261 pci_bits |= PCI_COMMAND_MEMORY;
262 if (match & (VGA_RSRC_LEGACY_IO|VGA_RSRC_NORMAL_IO))
263 pci_bits |= PCI_COMMAND_IO;
264 }
265
266 if (change_bridge)
267 flags |= PCI_VGA_STATE_CHANGE_BRIDGE;
268
269 pci_set_vga_state(conflict->pdev, false, pci_bits, flags);
270 conflict->owns &= ~match;
271 /* If he also owned non-legacy, that is no longer the case */
272 if (match & VGA_RSRC_LEGACY_MEM)
273 conflict->owns &= ~VGA_RSRC_NORMAL_MEM;
274 if (match & VGA_RSRC_LEGACY_IO)
275 conflict->owns &= ~VGA_RSRC_NORMAL_IO;
276 }
277
278enable_them:
279 /* ok dude, we got it, everybody conflicting has been disabled, let's
280 * enable us. Make sure we don't mark a bit in "owns" that we don't
281 * also have in "decodes". We can lock resources we don't decode but
282 * not own them.
283 */
284 flags = 0;
285 pci_bits = 0;
286
287 if (!vgadev->bridge_has_one_vga) {
288 flags |= PCI_VGA_STATE_CHANGE_DECODES;
289 if (wants & (VGA_RSRC_LEGACY_MEM|VGA_RSRC_NORMAL_MEM))
290 pci_bits |= PCI_COMMAND_MEMORY;
291 if (wants & (VGA_RSRC_LEGACY_IO|VGA_RSRC_NORMAL_IO))
292 pci_bits |= PCI_COMMAND_IO;
293 }
294 if (!!(wants & VGA_RSRC_LEGACY_MASK))
295 flags |= PCI_VGA_STATE_CHANGE_BRIDGE;
296
297 pci_set_vga_state(vgadev->pdev, true, pci_bits, flags);
298
299 if (!vgadev->bridge_has_one_vga) {
300 vga_irq_set_state(vgadev, true);
301 }
302 vgadev->owns |= (wants & vgadev->decodes);
303lock_them:
304 vgadev->locks |= (rsrc & VGA_RSRC_LEGACY_MASK);
305 if (rsrc & VGA_RSRC_LEGACY_IO)
306 vgadev->io_lock_cnt++;
307 if (rsrc & VGA_RSRC_LEGACY_MEM)
308 vgadev->mem_lock_cnt++;
309 if (rsrc & VGA_RSRC_NORMAL_IO)
310 vgadev->io_norm_cnt++;
311 if (rsrc & VGA_RSRC_NORMAL_MEM)
312 vgadev->mem_norm_cnt++;
313
314 return NULL;
315}
316
317static void __vga_put(struct vga_device *vgadev, unsigned int rsrc)
318{
319 unsigned int old_locks = vgadev->locks;
320
321 pr_debug("%s\n", __func__);
322
323 /* Update our counters, and account for equivalent legacy resources
324 * if we decode them
325 */
326 if ((rsrc & VGA_RSRC_NORMAL_IO) && vgadev->io_norm_cnt > 0) {
327 vgadev->io_norm_cnt--;
328 if (vgadev->decodes & VGA_RSRC_LEGACY_IO)
329 rsrc |= VGA_RSRC_LEGACY_IO;
330 }
331 if ((rsrc & VGA_RSRC_NORMAL_MEM) && vgadev->mem_norm_cnt > 0) {
332 vgadev->mem_norm_cnt--;
333 if (vgadev->decodes & VGA_RSRC_LEGACY_MEM)
334 rsrc |= VGA_RSRC_LEGACY_MEM;
335 }
336 if ((rsrc & VGA_RSRC_LEGACY_IO) && vgadev->io_lock_cnt > 0)
337 vgadev->io_lock_cnt--;
338 if ((rsrc & VGA_RSRC_LEGACY_MEM) && vgadev->mem_lock_cnt > 0)
339 vgadev->mem_lock_cnt--;
340
341 /* Just clear lock bits, we do lazy operations so we don't really
342 * have to bother about anything else at this point
343 */
344 if (vgadev->io_lock_cnt == 0)
345 vgadev->locks &= ~VGA_RSRC_LEGACY_IO;
346 if (vgadev->mem_lock_cnt == 0)
347 vgadev->locks &= ~VGA_RSRC_LEGACY_MEM;
348
349 /* Kick the wait queue in case somebody was waiting if we actually
350 * released something
351 */
352 if (old_locks != vgadev->locks)
353 wake_up_all(&vga_wait_queue);
354}
355
356int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible)
357{
358 struct vga_device *vgadev, *conflict;
359 unsigned long flags;
360 wait_queue_t wait;
361 int rc = 0;
362
363 vga_check_first_use();
364 /* The one who calls us should check for this, but lets be sure... */
365 if (pdev == NULL)
366 pdev = vga_default_device();
367 if (pdev == NULL)
368 return 0;
369
370 for (;;) {
371 spin_lock_irqsave(&vga_lock, flags);
372 vgadev = vgadev_find(pdev);
373 if (vgadev == NULL) {
374 spin_unlock_irqrestore(&vga_lock, flags);
375 rc = -ENODEV;
376 break;
377 }
378 conflict = __vga_tryget(vgadev, rsrc);
379 spin_unlock_irqrestore(&vga_lock, flags);
380 if (conflict == NULL)
381 break;
382
383
384 /* We have a conflict, we wait until somebody kicks the
385 * work queue. Currently we have one work queue that we
386 * kick each time some resources are released, but it would
387 * be fairly easy to have a per device one so that we only
388 * need to attach to the conflicting device
389 */
390 init_waitqueue_entry(&wait, current);
391 add_wait_queue(&vga_wait_queue, &wait);
392 set_current_state(interruptible ?
393 TASK_INTERRUPTIBLE :
394 TASK_UNINTERRUPTIBLE);
395 if (signal_pending(current)) {
396 rc = -EINTR;
397 break;
398 }
399 schedule();
400 remove_wait_queue(&vga_wait_queue, &wait);
401 set_current_state(TASK_RUNNING);
402 }
403 return rc;
404}
405EXPORT_SYMBOL(vga_get);
406
407int vga_tryget(struct pci_dev *pdev, unsigned int rsrc)
408{
409 struct vga_device *vgadev;
410 unsigned long flags;
411 int rc = 0;
412
413 vga_check_first_use();
414
415 /* The one who calls us should check for this, but lets be sure... */
416 if (pdev == NULL)
417 pdev = vga_default_device();
418 if (pdev == NULL)
419 return 0;
420 spin_lock_irqsave(&vga_lock, flags);
421 vgadev = vgadev_find(pdev);
422 if (vgadev == NULL) {
423 rc = -ENODEV;
424 goto bail;
425 }
426 if (__vga_tryget(vgadev, rsrc))
427 rc = -EBUSY;
428bail:
429 spin_unlock_irqrestore(&vga_lock, flags);
430 return rc;
431}
432EXPORT_SYMBOL(vga_tryget);
433
434void vga_put(struct pci_dev *pdev, unsigned int rsrc)
435{
436 struct vga_device *vgadev;
437 unsigned long flags;
438
439 /* The one who calls us should check for this, but lets be sure... */
440 if (pdev == NULL)
441 pdev = vga_default_device();
442 if (pdev == NULL)
443 return;
444 spin_lock_irqsave(&vga_lock, flags);
445 vgadev = vgadev_find(pdev);
446 if (vgadev == NULL)
447 goto bail;
448 __vga_put(vgadev, rsrc);
449bail:
450 spin_unlock_irqrestore(&vga_lock, flags);
451}
452EXPORT_SYMBOL(vga_put);
453
454/* Rules for using a bridge to control a VGA descendant decoding:
455 if a bridge has only one VGA descendant then it can be used
456 to control the VGA routing for that device.
457 It should always use the bridge closest to the device to control it.
458 If a bridge has a direct VGA descendant, but also have a sub-bridge
459 VGA descendant then we cannot use that bridge to control the direct VGA descendant.
460 So for every device we register, we need to iterate all its parent bridges
461 so we can invalidate any devices using them properly.
462*/
463static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev)
464{
465 struct vga_device *same_bridge_vgadev;
466 struct pci_bus *new_bus, *bus;
467 struct pci_dev *new_bridge, *bridge;
468
469 vgadev->bridge_has_one_vga = true;
470
471 if (list_empty(&vga_list))
472 return;
473
474 /* okay iterate the new devices bridge hierarachy */
475 new_bus = vgadev->pdev->bus;
476 while (new_bus) {
477 new_bridge = new_bus->self;
478
479 /* go through list of devices already registered */
480 list_for_each_entry(same_bridge_vgadev, &vga_list, list) {
481 bus = same_bridge_vgadev->pdev->bus;
482 bridge = bus->self;
483
484 /* see if the share a bridge with this device */
485 if (new_bridge == bridge) {
486 /* if their direct parent bridge is the same
487 as any bridge of this device then it can't be used
488 for that device */
489 same_bridge_vgadev->bridge_has_one_vga = false;
490 }
491
492 /* now iterate the previous devices bridge hierarchy */
493 /* if the new devices parent bridge is in the other devices
494 hierarchy then we can't use it to control this device */
495 while (bus) {
496 bridge = bus->self;
497 if (bridge) {
498 if (bridge == vgadev->pdev->bus->self)
499 vgadev->bridge_has_one_vga = false;
500 }
501 bus = bus->parent;
502 }
503 }
504 new_bus = new_bus->parent;
505 }
506}
507
508/*
509 * Currently, we assume that the "initial" setup of the system is
510 * not sane, that is we come up with conflicting devices and let
511 * the arbiter's client decides if devices decodes or not legacy
512 * things.
513 */
514static bool vga_arbiter_add_pci_device(struct pci_dev *pdev)
515{
516 struct vga_device *vgadev;
517 unsigned long flags;
518 struct pci_bus *bus;
519 struct pci_dev *bridge;
520 u16 cmd;
521
522 /* Only deal with VGA class devices */
523 if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
524 return false;
525
526 /* Allocate structure */
527 vgadev = kmalloc(sizeof(struct vga_device), GFP_KERNEL);
528 if (vgadev == NULL) {
529 pr_err("vgaarb: failed to allocate pci device\n");
530 /* What to do on allocation failure ? For now, let's
531 * just do nothing, I'm not sure there is anything saner
532 * to be done
533 */
534 return false;
535 }
536
537 memset(vgadev, 0, sizeof(*vgadev));
538
539 /* Take lock & check for duplicates */
540 spin_lock_irqsave(&vga_lock, flags);
541 if (vgadev_find(pdev) != NULL) {
542 BUG_ON(1);
543 goto fail;
544 }
545 vgadev->pdev = pdev;
546
547 /* By default, assume we decode everything */
548 vgadev->decodes = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM |
549 VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
550
551 /* by default mark it as decoding */
552 vga_decode_count++;
553 /* Mark that we "own" resources based on our enables, we will
554 * clear that below if the bridge isn't forwarding
555 */
556 pci_read_config_word(pdev, PCI_COMMAND, &cmd);
557 if (cmd & PCI_COMMAND_IO)
558 vgadev->owns |= VGA_RSRC_LEGACY_IO;
559 if (cmd & PCI_COMMAND_MEMORY)
560 vgadev->owns |= VGA_RSRC_LEGACY_MEM;
561
562 /* Check if VGA cycles can get down to us */
563 bus = pdev->bus;
564 while (bus) {
565 bridge = bus->self;
566 if (bridge) {
567 u16 l;
568 pci_read_config_word(bridge, PCI_BRIDGE_CONTROL,
569 &l);
570 if (!(l & PCI_BRIDGE_CTL_VGA)) {
571 vgadev->owns = 0;
572 break;
573 }
574 }
575 bus = bus->parent;
576 }
577
578 /* Deal with VGA default device. Use first enabled one
579 * by default if arch doesn't have it's own hook
580 */
581#ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE
582 if (vga_default == NULL &&
583 ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK))
584 vga_set_default_device(pdev);
585#endif
586
587 vga_arbiter_check_bridge_sharing(vgadev);
588
589 /* Add to the list */
590 list_add(&vgadev->list, &vga_list);
591 vga_count++;
592 pr_info("vgaarb: device added: PCI:%s,decodes=%s,owns=%s,locks=%s\n",
593 pci_name(pdev),
594 vga_iostate_to_str(vgadev->decodes),
595 vga_iostate_to_str(vgadev->owns),
596 vga_iostate_to_str(vgadev->locks));
597
598 spin_unlock_irqrestore(&vga_lock, flags);
599 return true;
600fail:
601 spin_unlock_irqrestore(&vga_lock, flags);
602 kfree(vgadev);
603 return false;
604}
605
606static bool vga_arbiter_del_pci_device(struct pci_dev *pdev)
607{
608 struct vga_device *vgadev;
609 unsigned long flags;
610 bool ret = true;
611
612 spin_lock_irqsave(&vga_lock, flags);
613 vgadev = vgadev_find(pdev);
614 if (vgadev == NULL) {
615 ret = false;
616 goto bail;
617 }
618
619#ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE
620 if (vga_default == pdev)
621 vga_set_default_device(NULL);
622#endif
623
624 if (vgadev->decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM))
625 vga_decode_count--;
626
627 /* Remove entry from list */
628 list_del(&vgadev->list);
629 vga_count--;
630 /* Notify userland driver that the device is gone so it discards
631 * it's copies of the pci_dev pointer
632 */
633 vga_arb_device_card_gone(pdev);
634
635 /* Wake up all possible waiters */
636 wake_up_all(&vga_wait_queue);
637bail:
638 spin_unlock_irqrestore(&vga_lock, flags);
639 kfree(vgadev);
640 return ret;
641}
642
643/* this is called with the lock */
644static inline void vga_update_device_decodes(struct vga_device *vgadev,
645 int new_decodes)
646{
647 int old_decodes, decodes_removed, decodes_unlocked;
648
649 old_decodes = vgadev->decodes;
650 decodes_removed = ~new_decodes & old_decodes;
651 decodes_unlocked = vgadev->locks & decodes_removed;
652 vgadev->owns &= ~decodes_removed;
653 vgadev->decodes = new_decodes;
654
655 pr_info("vgaarb: device changed decodes: PCI:%s,olddecodes=%s,decodes=%s:owns=%s\n",
656 pci_name(vgadev->pdev),
657 vga_iostate_to_str(old_decodes),
658 vga_iostate_to_str(vgadev->decodes),
659 vga_iostate_to_str(vgadev->owns));
660
661 /* if we removed locked decodes, lock count goes to zero, and release */
662 if (decodes_unlocked) {
663 if (decodes_unlocked & VGA_RSRC_LEGACY_IO)
664 vgadev->io_lock_cnt = 0;
665 if (decodes_unlocked & VGA_RSRC_LEGACY_MEM)
666 vgadev->mem_lock_cnt = 0;
667 __vga_put(vgadev, decodes_unlocked);
668 }
669
670 /* change decodes counter */
671 if (old_decodes & VGA_RSRC_LEGACY_MASK &&
672 !(new_decodes & VGA_RSRC_LEGACY_MASK))
673 vga_decode_count--;
674 if (!(old_decodes & VGA_RSRC_LEGACY_MASK) &&
675 new_decodes & VGA_RSRC_LEGACY_MASK)
676 vga_decode_count++;
677 pr_debug("vgaarb: decoding count now is: %d\n", vga_decode_count);
678}
679
680static void __vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes, bool userspace)
681{
682 struct vga_device *vgadev;
683 unsigned long flags;
684
685 decodes &= VGA_RSRC_LEGACY_MASK;
686
687 spin_lock_irqsave(&vga_lock, flags);
688 vgadev = vgadev_find(pdev);
689 if (vgadev == NULL)
690 goto bail;
691
692 /* don't let userspace futz with kernel driver decodes */
693 if (userspace && vgadev->set_vga_decode)
694 goto bail;
695
696 /* update the device decodes + counter */
697 vga_update_device_decodes(vgadev, decodes);
698
699 /* XXX if somebody is going from "doesn't decode" to "decodes" state
700 * here, additional care must be taken as we may have pending owner
701 * ship of non-legacy region ...
702 */
703bail:
704 spin_unlock_irqrestore(&vga_lock, flags);
705}
706
707void vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes)
708{
709 __vga_set_legacy_decoding(pdev, decodes, false);
710}
711EXPORT_SYMBOL(vga_set_legacy_decoding);
712
713/* call with NULL to unregister */
714int vga_client_register(struct pci_dev *pdev, void *cookie,
715 void (*irq_set_state)(void *cookie, bool state),
716 unsigned int (*set_vga_decode)(void *cookie, bool decode))
717{
718 int ret = -ENODEV;
719 struct vga_device *vgadev;
720 unsigned long flags;
721
722 spin_lock_irqsave(&vga_lock, flags);
723 vgadev = vgadev_find(pdev);
724 if (!vgadev)
725 goto bail;
726
727 vgadev->irq_set_state = irq_set_state;
728 vgadev->set_vga_decode = set_vga_decode;
729 vgadev->cookie = cookie;
730 ret = 0;
731
732bail:
733 spin_unlock_irqrestore(&vga_lock, flags);
734 return ret;
735
736}
737EXPORT_SYMBOL(vga_client_register);
738
739/*
740 * Char driver implementation
741 *
742 * Semantics is:
743 *
744 * open : open user instance of the arbitrer. by default, it's
745 * attached to the default VGA device of the system.
746 *
747 * close : close user instance, release locks
748 *
749 * read : return a string indicating the status of the target.
750 * an IO state string is of the form {io,mem,io+mem,none},
751 * mc and ic are respectively mem and io lock counts (for
752 * debugging/diagnostic only). "decodes" indicate what the
753 * card currently decodes, "owns" indicates what is currently
754 * enabled on it, and "locks" indicates what is locked by this
755 * card. If the card is unplugged, we get "invalid" then for
756 * card_ID and an -ENODEV error is returned for any command
757 * until a new card is targeted
758 *
759 * "<card_ID>,decodes=<io_state>,owns=<io_state>,locks=<io_state> (ic,mc)"
760 *
761 * write : write a command to the arbiter. List of commands is:
762 *
763 * target <card_ID> : switch target to card <card_ID> (see below)
764 * lock <io_state> : acquires locks on target ("none" is invalid io_state)
765 * trylock <io_state> : non-blocking acquire locks on target
766 * unlock <io_state> : release locks on target
767 * unlock all : release all locks on target held by this user
768 * decodes <io_state> : set the legacy decoding attributes for the card
769 *
770 * poll : event if something change on any card (not just the target)
771 *
772 * card_ID is of the form "PCI:domain:bus:dev.fn". It can be set to "default"
773 * to go back to the system default card (TODO: not implemented yet).
774 * Currently, only PCI is supported as a prefix, but the userland API may
775 * support other bus types in the future, even if the current kernel
776 * implementation doesn't.
777 *
778 * Note about locks:
779 *
780 * The driver keeps track of which user has what locks on which card. It
781 * supports stacking, like the kernel one. This complexifies the implementation
782 * a bit, but makes the arbiter more tolerant to userspace problems and able
783 * to properly cleanup in all cases when a process dies.
784 * Currently, a max of 16 cards simultaneously can have locks issued from
785 * userspace for a given user (file descriptor instance) of the arbiter.
786 *
787 * If the device is hot-unplugged, there is a hook inside the module to notify
788 * they being added/removed in the system and automatically added/removed in
789 * the arbiter.
790 */
791
792#define MAX_USER_CARDS CONFIG_VGA_ARB_MAX_GPUS
793#define PCI_INVALID_CARD ((struct pci_dev *)-1UL)
794
795/*
796 * Each user has an array of these, tracking which cards have locks
797 */
798struct vga_arb_user_card {
799 struct pci_dev *pdev;
800 unsigned int mem_cnt;
801 unsigned int io_cnt;
802};
803
804struct vga_arb_private {
805 struct list_head list;
806 struct pci_dev *target;
807 struct vga_arb_user_card cards[MAX_USER_CARDS];
808 spinlock_t lock;
809};
810
811static LIST_HEAD(vga_user_list);
812static DEFINE_SPINLOCK(vga_user_lock);
813
814
815/*
816 * This function gets a string in the format: "PCI:domain:bus:dev.fn" and
817 * returns the respective values. If the string is not in this format,
818 * it returns 0.
819 */
820static int vga_pci_str_to_vars(char *buf, int count, unsigned int *domain,
821 unsigned int *bus, unsigned int *devfn)
822{
823 int n;
824 unsigned int slot, func;
825
826
827 n = sscanf(buf, "PCI:%x:%x:%x.%x", domain, bus, &slot, &func);
828 if (n != 4)
829 return 0;
830
831 *devfn = PCI_DEVFN(slot, func);
832
833 return 1;
834}
835
836static ssize_t vga_arb_read(struct file *file, char __user * buf,
837 size_t count, loff_t *ppos)
838{
839 struct vga_arb_private *priv = file->private_data;
840 struct vga_device *vgadev;
841 struct pci_dev *pdev;
842 unsigned long flags;
843 size_t len;
844 int rc;
845 char *lbuf;
846
847 lbuf = kmalloc(1024, GFP_KERNEL);
848 if (lbuf == NULL)
849 return -ENOMEM;
850
851 /* Shields against vga_arb_device_card_gone (pci_dev going
852 * away), and allows access to vga list
853 */
854 spin_lock_irqsave(&vga_lock, flags);
855
856 /* If we are targeting the default, use it */
857 pdev = priv->target;
858 if (pdev == NULL || pdev == PCI_INVALID_CARD) {
859 spin_unlock_irqrestore(&vga_lock, flags);
860 len = sprintf(lbuf, "invalid");
861 goto done;
862 }
863
864 /* Find card vgadev structure */
865 vgadev = vgadev_find(pdev);
866 if (vgadev == NULL) {
867 /* Wow, it's not in the list, that shouldn't happen,
868 * let's fix us up and return invalid card
869 */
870 if (pdev == priv->target)
871 vga_arb_device_card_gone(pdev);
872 spin_unlock_irqrestore(&vga_lock, flags);
873 len = sprintf(lbuf, "invalid");
874 goto done;
875 }
876
877 /* Fill the buffer with infos */
878 len = snprintf(lbuf, 1024,
879 "count:%d,PCI:%s,decodes=%s,owns=%s,locks=%s(%d:%d)\n",
880 vga_decode_count, pci_name(pdev),
881 vga_iostate_to_str(vgadev->decodes),
882 vga_iostate_to_str(vgadev->owns),
883 vga_iostate_to_str(vgadev->locks),
884 vgadev->io_lock_cnt, vgadev->mem_lock_cnt);
885
886 spin_unlock_irqrestore(&vga_lock, flags);
887done:
888
889 /* Copy that to user */
890 if (len > count)
891 len = count;
892 rc = copy_to_user(buf, lbuf, len);
893 kfree(lbuf);
894 if (rc)
895 return -EFAULT;
896 return len;
897}
898
899/*
900 * TODO: To avoid parsing inside kernel and to improve the speed we may
901 * consider use ioctl here
902 */
903static ssize_t vga_arb_write(struct file *file, const char __user * buf,
904 size_t count, loff_t *ppos)
905{
906 struct vga_arb_private *priv = file->private_data;
907 struct vga_arb_user_card *uc = NULL;
908 struct pci_dev *pdev;
909
910 unsigned int io_state;
911
912 char *kbuf, *curr_pos;
913 size_t remaining = count;
914
915 int ret_val;
916 int i;
917
918
919 kbuf = kmalloc(count + 1, GFP_KERNEL);
920 if (!kbuf)
921 return -ENOMEM;
922
923 if (copy_from_user(kbuf, buf, count)) {
924 kfree(kbuf);
925 return -EFAULT;
926 }
927 curr_pos = kbuf;
928 kbuf[count] = '\0'; /* Just to make sure... */
929
930 if (strncmp(curr_pos, "lock ", 5) == 0) {
931 curr_pos += 5;
932 remaining -= 5;
933
934 pr_debug("client 0x%p called 'lock'\n", priv);
935
936 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) {
937 ret_val = -EPROTO;
938 goto done;
939 }
940 if (io_state == VGA_RSRC_NONE) {
941 ret_val = -EPROTO;
942 goto done;
943 }
944
945 pdev = priv->target;
946 if (priv->target == NULL) {
947 ret_val = -ENODEV;
948 goto done;
949 }
950
951 vga_get_uninterruptible(pdev, io_state);
952
953 /* Update the client's locks lists... */
954 for (i = 0; i < MAX_USER_CARDS; i++) {
955 if (priv->cards[i].pdev == pdev) {
956 if (io_state & VGA_RSRC_LEGACY_IO)
957 priv->cards[i].io_cnt++;
958 if (io_state & VGA_RSRC_LEGACY_MEM)
959 priv->cards[i].mem_cnt++;
960 break;
961 }
962 }
963
964 ret_val = count;
965 goto done;
966 } else if (strncmp(curr_pos, "unlock ", 7) == 0) {
967 curr_pos += 7;
968 remaining -= 7;
969
970 pr_debug("client 0x%p called 'unlock'\n", priv);
971
972 if (strncmp(curr_pos, "all", 3) == 0)
973 io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM;
974 else {
975 if (!vga_str_to_iostate
976 (curr_pos, remaining, &io_state)) {
977 ret_val = -EPROTO;
978 goto done;
979 }
980 /* TODO: Add this?
981 if (io_state == VGA_RSRC_NONE) {
982 ret_val = -EPROTO;
983 goto done;
984 }
985 */
986 }
987
988 pdev = priv->target;
989 if (priv->target == NULL) {
990 ret_val = -ENODEV;
991 goto done;
992 }
993 for (i = 0; i < MAX_USER_CARDS; i++) {
994 if (priv->cards[i].pdev == pdev)
995 uc = &priv->cards[i];
996 }
997
998 if (!uc) {
999 ret_val = -EINVAL;
1000 goto done;
1001 }
1002
1003 if (io_state & VGA_RSRC_LEGACY_IO && uc->io_cnt == 0) {
1004 ret_val = -EINVAL;
1005 goto done;
1006 }
1007
1008 if (io_state & VGA_RSRC_LEGACY_MEM && uc->mem_cnt == 0) {
1009 ret_val = -EINVAL;
1010 goto done;
1011 }
1012
1013 vga_put(pdev, io_state);
1014
1015 if (io_state & VGA_RSRC_LEGACY_IO)
1016 uc->io_cnt--;
1017 if (io_state & VGA_RSRC_LEGACY_MEM)
1018 uc->mem_cnt--;
1019
1020 ret_val = count;
1021 goto done;
1022 } else if (strncmp(curr_pos, "trylock ", 8) == 0) {
1023 curr_pos += 8;
1024 remaining -= 8;
1025
1026 pr_debug("client 0x%p called 'trylock'\n", priv);
1027
1028 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) {
1029 ret_val = -EPROTO;
1030 goto done;
1031 }
1032 /* TODO: Add this?
1033 if (io_state == VGA_RSRC_NONE) {
1034 ret_val = -EPROTO;
1035 goto done;
1036 }
1037 */
1038
1039 pdev = priv->target;
1040 if (priv->target == NULL) {
1041 ret_val = -ENODEV;
1042 goto done;
1043 }
1044
1045 if (vga_tryget(pdev, io_state)) {
1046 /* Update the client's locks lists... */
1047 for (i = 0; i < MAX_USER_CARDS; i++) {
1048 if (priv->cards[i].pdev == pdev) {
1049 if (io_state & VGA_RSRC_LEGACY_IO)
1050 priv->cards[i].io_cnt++;
1051 if (io_state & VGA_RSRC_LEGACY_MEM)
1052 priv->cards[i].mem_cnt++;
1053 break;
1054 }
1055 }
1056 ret_val = count;
1057 goto done;
1058 } else {
1059 ret_val = -EBUSY;
1060 goto done;
1061 }
1062
1063 } else if (strncmp(curr_pos, "target ", 7) == 0) {
1064 unsigned int domain, bus, devfn;
1065 struct vga_device *vgadev;
1066
1067 curr_pos += 7;
1068 remaining -= 7;
1069 pr_debug("client 0x%p called 'target'\n", priv);
1070 /* if target is default */
1071 if (!strncmp(curr_pos, "default", 7))
1072 pdev = pci_dev_get(vga_default_device());
1073 else {
1074 if (!vga_pci_str_to_vars(curr_pos, remaining,
1075 &domain, &bus, &devfn)) {
1076 ret_val = -EPROTO;
1077 goto done;
1078 }
1079 pr_debug("vgaarb: %s ==> %x:%x:%x.%x\n", curr_pos,
1080 domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn));
1081
1082 pdev = pci_get_domain_bus_and_slot(domain, bus, devfn);
1083 pr_debug("vgaarb: pdev %p\n", pdev);
1084 if (!pdev) {
1085 pr_err("vgaarb: invalid PCI address %x:%x:%x\n",
1086 domain, bus, devfn);
1087 ret_val = -ENODEV;
1088 goto done;
1089 }
1090 }
1091
1092 vgadev = vgadev_find(pdev);
1093 pr_debug("vgaarb: vgadev %p\n", vgadev);
1094 if (vgadev == NULL) {
1095 pr_err("vgaarb: this pci device is not a vga device\n");
1096 pci_dev_put(pdev);
1097 ret_val = -ENODEV;
1098 goto done;
1099 }
1100
1101 priv->target = pdev;
1102 for (i = 0; i < MAX_USER_CARDS; i++) {
1103 if (priv->cards[i].pdev == pdev)
1104 break;
1105 if (priv->cards[i].pdev == NULL) {
1106 priv->cards[i].pdev = pdev;
1107 priv->cards[i].io_cnt = 0;
1108 priv->cards[i].mem_cnt = 0;
1109 break;
1110 }
1111 }
1112 if (i == MAX_USER_CARDS) {
1113 pr_err("vgaarb: maximum user cards (%d) number reached!\n",
1114 MAX_USER_CARDS);
1115 pci_dev_put(pdev);
1116 /* XXX: which value to return? */
1117 ret_val = -ENOMEM;
1118 goto done;
1119 }
1120
1121 ret_val = count;
1122 pci_dev_put(pdev);
1123 goto done;
1124
1125
1126 } else if (strncmp(curr_pos, "decodes ", 8) == 0) {
1127 curr_pos += 8;
1128 remaining -= 8;
1129 pr_debug("vgaarb: client 0x%p called 'decodes'\n", priv);
1130
1131 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) {
1132 ret_val = -EPROTO;
1133 goto done;
1134 }
1135 pdev = priv->target;
1136 if (priv->target == NULL) {
1137 ret_val = -ENODEV;
1138 goto done;
1139 }
1140
1141 __vga_set_legacy_decoding(pdev, io_state, true);
1142 ret_val = count;
1143 goto done;
1144 }
1145 /* If we got here, the message written is not part of the protocol! */
1146 kfree(kbuf);
1147 return -EPROTO;
1148
1149done:
1150 kfree(kbuf);
1151 return ret_val;
1152}
1153
1154static unsigned int vga_arb_fpoll(struct file *file, poll_table * wait)
1155{
1156 struct vga_arb_private *priv = file->private_data;
1157
1158 pr_debug("%s\n", __func__);
1159
1160 if (priv == NULL)
1161 return -ENODEV;
1162 poll_wait(file, &vga_wait_queue, wait);
1163 return POLLIN;
1164}
1165
1166static int vga_arb_open(struct inode *inode, struct file *file)
1167{
1168 struct vga_arb_private *priv;
1169 unsigned long flags;
1170
1171 pr_debug("%s\n", __func__);
1172
1173 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
1174 if (priv == NULL)
1175 return -ENOMEM;
1176 spin_lock_init(&priv->lock);
1177 file->private_data = priv;
1178
1179 spin_lock_irqsave(&vga_user_lock, flags);
1180 list_add(&priv->list, &vga_user_list);
1181 spin_unlock_irqrestore(&vga_user_lock, flags);
1182
1183 /* Set the client' lists of locks */
1184 priv->target = vga_default_device(); /* Maybe this is still null! */
1185 priv->cards[0].pdev = priv->target;
1186 priv->cards[0].io_cnt = 0;
1187 priv->cards[0].mem_cnt = 0;
1188
1189
1190 return 0;
1191}
1192
1193static int vga_arb_release(struct inode *inode, struct file *file)
1194{
1195 struct vga_arb_private *priv = file->private_data;
1196 struct vga_arb_user_card *uc;
1197 unsigned long flags;
1198 int i;
1199
1200 pr_debug("%s\n", __func__);
1201
1202 if (priv == NULL)
1203 return -ENODEV;
1204
1205 spin_lock_irqsave(&vga_user_lock, flags);
1206 list_del(&priv->list);
1207 for (i = 0; i < MAX_USER_CARDS; i++) {
1208 uc = &priv->cards[i];
1209 if (uc->pdev == NULL)
1210 continue;
1211 pr_debug("uc->io_cnt == %d, uc->mem_cnt == %d\n",
1212 uc->io_cnt, uc->mem_cnt);
1213 while (uc->io_cnt--)
1214 vga_put(uc->pdev, VGA_RSRC_LEGACY_IO);
1215 while (uc->mem_cnt--)
1216 vga_put(uc->pdev, VGA_RSRC_LEGACY_MEM);
1217 }
1218 spin_unlock_irqrestore(&vga_user_lock, flags);
1219
1220 kfree(priv);
1221
1222 return 0;
1223}
1224
1225static void vga_arb_device_card_gone(struct pci_dev *pdev)
1226{
1227}
1228
1229/*
1230 * callback any registered clients to let them know we have a
1231 * change in VGA cards
1232 */
1233static void vga_arbiter_notify_clients(void)
1234{
1235 struct vga_device *vgadev;
1236 unsigned long flags;
1237 uint32_t new_decodes;
1238 bool new_state;
1239
1240 if (!vga_arbiter_used)
1241 return;
1242
1243 spin_lock_irqsave(&vga_lock, flags);
1244 list_for_each_entry(vgadev, &vga_list, list) {
1245 if (vga_count > 1)
1246 new_state = false;
1247 else
1248 new_state = true;
1249 if (vgadev->set_vga_decode) {
1250 new_decodes = vgadev->set_vga_decode(vgadev->cookie, new_state);
1251 vga_update_device_decodes(vgadev, new_decodes);
1252 }
1253 }
1254 spin_unlock_irqrestore(&vga_lock, flags);
1255}
1256
1257static int pci_notify(struct notifier_block *nb, unsigned long action,
1258 void *data)
1259{
1260 struct device *dev = data;
1261 struct pci_dev *pdev = to_pci_dev(dev);
1262 bool notify = false;
1263
1264 pr_debug("%s\n", __func__);
1265
1266 /* For now we're only intereted in devices added and removed. I didn't
1267 * test this thing here, so someone needs to double check for the
1268 * cases of hotplugable vga cards. */
1269 if (action == BUS_NOTIFY_ADD_DEVICE)
1270 notify = vga_arbiter_add_pci_device(pdev);
1271 else if (action == BUS_NOTIFY_DEL_DEVICE)
1272 notify = vga_arbiter_del_pci_device(pdev);
1273
1274 if (notify)
1275 vga_arbiter_notify_clients();
1276 return 0;
1277}
1278
1279static struct notifier_block pci_notifier = {
1280 .notifier_call = pci_notify,
1281};
1282
1283static const struct file_operations vga_arb_device_fops = {
1284 .read = vga_arb_read,
1285 .write = vga_arb_write,
1286 .poll = vga_arb_fpoll,
1287 .open = vga_arb_open,
1288 .release = vga_arb_release,
1289 .llseek = noop_llseek,
1290};
1291
1292static struct miscdevice vga_arb_device = {
1293 MISC_DYNAMIC_MINOR, "vga_arbiter", &vga_arb_device_fops
1294};
1295
1296static int __init vga_arb_device_init(void)
1297{
1298 int rc;
1299 struct pci_dev *pdev;
1300 struct vga_device *vgadev;
1301
1302 rc = misc_register(&vga_arb_device);
1303 if (rc < 0)
1304 pr_err("vgaarb: error %d registering device\n", rc);
1305
1306 bus_register_notifier(&pci_bus_type, &pci_notifier);
1307
1308 /* We add all pci devices satisfying vga class in the arbiter by
1309 * default */
1310 pdev = NULL;
1311 while ((pdev =
1312 pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
1313 PCI_ANY_ID, pdev)) != NULL)
1314 vga_arbiter_add_pci_device(pdev);
1315
1316 pr_info("vgaarb: loaded\n");
1317
1318 list_for_each_entry(vgadev, &vga_list, list) {
1319 if (vgadev->bridge_has_one_vga)
1320 pr_info("vgaarb: bridge control possible %s\n", pci_name(vgadev->pdev));
1321 else
1322 pr_info("vgaarb: no bridge control possible %s\n", pci_name(vgadev->pdev));
1323 }
1324 return rc;
1325}
1326subsys_initcall(vga_arb_device_init);
1/*
2 * vgaarb.c: Implements the VGA arbitration. For details refer to
3 * Documentation/vgaarbiter.txt
4 *
5 *
6 * (C) Copyright 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>
7 * (C) Copyright 2007 Paulo R. Zanoni <przanoni@gmail.com>
8 * (C) Copyright 2007, 2009 Tiago Vignatti <vignatti@freedesktop.org>
9 *
10 * Permission is hereby granted, free of charge, to any person obtaining a
11 * copy of this software and associated documentation files (the "Software"),
12 * to deal in the Software without restriction, including without limitation
13 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
14 * and/or sell copies of the Software, and to permit persons to whom the
15 * Software is furnished to do so, subject to the following conditions:
16 *
17 * The above copyright notice and this permission notice (including the next
18 * paragraph) shall be included in all copies or substantial portions of the
19 * Software.
20 *
21 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
22 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
23 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
24 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
25 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
26 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
27 * DEALINGS
28 * IN THE SOFTWARE.
29 *
30 */
31
32#define pr_fmt(fmt) "vgaarb: " fmt
33
34#define vgaarb_dbg(dev, fmt, arg...) dev_dbg(dev, "vgaarb: " fmt, ##arg)
35#define vgaarb_info(dev, fmt, arg...) dev_info(dev, "vgaarb: " fmt, ##arg)
36#define vgaarb_err(dev, fmt, arg...) dev_err(dev, "vgaarb: " fmt, ##arg)
37
38#include <linux/module.h>
39#include <linux/kernel.h>
40#include <linux/pci.h>
41#include <linux/errno.h>
42#include <linux/init.h>
43#include <linux/list.h>
44#include <linux/sched.h>
45#include <linux/wait.h>
46#include <linux/spinlock.h>
47#include <linux/poll.h>
48#include <linux/miscdevice.h>
49#include <linux/slab.h>
50#include <linux/screen_info.h>
51
52#include <linux/uaccess.h>
53
54#include <linux/vgaarb.h>
55
56static void vga_arbiter_notify_clients(void);
57/*
58 * We keep a list of all vga devices in the system to speed
59 * up the various operations of the arbiter
60 */
61struct vga_device {
62 struct list_head list;
63 struct pci_dev *pdev;
64 unsigned int decodes; /* what does it decodes */
65 unsigned int owns; /* what does it owns */
66 unsigned int locks; /* what does it locks */
67 unsigned int io_lock_cnt; /* legacy IO lock count */
68 unsigned int mem_lock_cnt; /* legacy MEM lock count */
69 unsigned int io_norm_cnt; /* normal IO count */
70 unsigned int mem_norm_cnt; /* normal MEM count */
71 bool bridge_has_one_vga;
72 /* allow IRQ enable/disable hook */
73 void *cookie;
74 void (*irq_set_state)(void *cookie, bool enable);
75 unsigned int (*set_vga_decode)(void *cookie, bool decode);
76};
77
78static LIST_HEAD(vga_list);
79static int vga_count, vga_decode_count;
80static bool vga_arbiter_used;
81static DEFINE_SPINLOCK(vga_lock);
82static DECLARE_WAIT_QUEUE_HEAD(vga_wait_queue);
83
84
85static const char *vga_iostate_to_str(unsigned int iostate)
86{
87 /* Ignore VGA_RSRC_IO and VGA_RSRC_MEM */
88 iostate &= VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM;
89 switch (iostate) {
90 case VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM:
91 return "io+mem";
92 case VGA_RSRC_LEGACY_IO:
93 return "io";
94 case VGA_RSRC_LEGACY_MEM:
95 return "mem";
96 }
97 return "none";
98}
99
100static int vga_str_to_iostate(char *buf, int str_size, int *io_state)
101{
102 /* we could in theory hand out locks on IO and mem
103 * separately to userspace but it can cause deadlocks */
104 if (strncmp(buf, "none", 4) == 0) {
105 *io_state = VGA_RSRC_NONE;
106 return 1;
107 }
108
109 /* XXX We're not chekcing the str_size! */
110 if (strncmp(buf, "io+mem", 6) == 0)
111 goto both;
112 else if (strncmp(buf, "io", 2) == 0)
113 goto both;
114 else if (strncmp(buf, "mem", 3) == 0)
115 goto both;
116 return 0;
117both:
118 *io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM;
119 return 1;
120}
121
122/* this is only used a cookie - it should not be dereferenced */
123static struct pci_dev *vga_default;
124
125static void vga_arb_device_card_gone(struct pci_dev *pdev);
126
127/* Find somebody in our list */
128static struct vga_device *vgadev_find(struct pci_dev *pdev)
129{
130 struct vga_device *vgadev;
131
132 list_for_each_entry(vgadev, &vga_list, list)
133 if (pdev == vgadev->pdev)
134 return vgadev;
135 return NULL;
136}
137
138/**
139 * vga_default_device - return the default VGA device, for vgacon
140 *
141 * This can be defined by the platform. The default implementation
142 * is rather dumb and will probably only work properly on single
143 * vga card setups and/or x86 platforms.
144 *
145 * If your VGA default device is not PCI, you'll have to return
146 * NULL here. In this case, I assume it will not conflict with
147 * any PCI card. If this is not true, I'll have to define two archs
148 * hooks for enabling/disabling the VGA default device if that is
149 * possible. This may be a problem with real _ISA_ VGA cards, in
150 * addition to a PCI one. I don't know at this point how to deal
151 * with that card. Can theirs IOs be disabled at all ? If not, then
152 * I suppose it's a matter of having the proper arch hook telling
153 * us about it, so we basically never allow anybody to succeed a
154 * vga_get()...
155 */
156struct pci_dev *vga_default_device(void)
157{
158 return vga_default;
159}
160EXPORT_SYMBOL_GPL(vga_default_device);
161
162void vga_set_default_device(struct pci_dev *pdev)
163{
164 if (vga_default == pdev)
165 return;
166
167 pci_dev_put(vga_default);
168 vga_default = pci_dev_get(pdev);
169}
170
171static inline void vga_irq_set_state(struct vga_device *vgadev, bool state)
172{
173 if (vgadev->irq_set_state)
174 vgadev->irq_set_state(vgadev->cookie, state);
175}
176
177
178/* If we don't ever use VGA arb we should avoid
179 turning off anything anywhere due to old X servers getting
180 confused about the boot device not being VGA */
181static void vga_check_first_use(void)
182{
183 /* we should inform all GPUs in the system that
184 * VGA arb has occurred and to try and disable resources
185 * if they can */
186 if (!vga_arbiter_used) {
187 vga_arbiter_used = true;
188 vga_arbiter_notify_clients();
189 }
190}
191
192static struct vga_device *__vga_tryget(struct vga_device *vgadev,
193 unsigned int rsrc)
194{
195 struct device *dev = &vgadev->pdev->dev;
196 unsigned int wants, legacy_wants, match;
197 struct vga_device *conflict;
198 unsigned int pci_bits;
199 u32 flags = 0;
200
201 /* Account for "normal" resources to lock. If we decode the legacy,
202 * counterpart, we need to request it as well
203 */
204 if ((rsrc & VGA_RSRC_NORMAL_IO) &&
205 (vgadev->decodes & VGA_RSRC_LEGACY_IO))
206 rsrc |= VGA_RSRC_LEGACY_IO;
207 if ((rsrc & VGA_RSRC_NORMAL_MEM) &&
208 (vgadev->decodes & VGA_RSRC_LEGACY_MEM))
209 rsrc |= VGA_RSRC_LEGACY_MEM;
210
211 vgaarb_dbg(dev, "%s: %d\n", __func__, rsrc);
212 vgaarb_dbg(dev, "%s: owns: %d\n", __func__, vgadev->owns);
213
214 /* Check what resources we need to acquire */
215 wants = rsrc & ~vgadev->owns;
216
217 /* We already own everything, just mark locked & bye bye */
218 if (wants == 0)
219 goto lock_them;
220
221 /* We don't need to request a legacy resource, we just enable
222 * appropriate decoding and go
223 */
224 legacy_wants = wants & VGA_RSRC_LEGACY_MASK;
225 if (legacy_wants == 0)
226 goto enable_them;
227
228 /* Ok, we don't, let's find out how we need to kick off */
229 list_for_each_entry(conflict, &vga_list, list) {
230 unsigned int lwants = legacy_wants;
231 unsigned int change_bridge = 0;
232
233 /* Don't conflict with myself */
234 if (vgadev == conflict)
235 continue;
236
237 /* Check if the architecture allows a conflict between those
238 * 2 devices or if they are on separate domains
239 */
240 if (!vga_conflicts(vgadev->pdev, conflict->pdev))
241 continue;
242
243 /* We have a possible conflict. before we go further, we must
244 * check if we sit on the same bus as the conflicting device.
245 * if we don't, then we must tie both IO and MEM resources
246 * together since there is only a single bit controlling
247 * VGA forwarding on P2P bridges
248 */
249 if (vgadev->pdev->bus != conflict->pdev->bus) {
250 change_bridge = 1;
251 lwants = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM;
252 }
253
254 /* Check if the guy has a lock on the resource. If he does,
255 * return the conflicting entry
256 */
257 if (conflict->locks & lwants)
258 return conflict;
259
260 /* Ok, now check if it owns the resource we want. We can
261 * lock resources that are not decoded, therefore a device
262 * can own resources it doesn't decode.
263 */
264 match = lwants & conflict->owns;
265 if (!match)
266 continue;
267
268 /* looks like he doesn't have a lock, we can steal
269 * them from him
270 */
271
272 flags = 0;
273 pci_bits = 0;
274
275 /* If we can't control legacy resources via the bridge, we
276 * also need to disable normal decoding.
277 */
278 if (!conflict->bridge_has_one_vga) {
279 if ((match & conflict->decodes) & VGA_RSRC_LEGACY_MEM)
280 pci_bits |= PCI_COMMAND_MEMORY;
281 if ((match & conflict->decodes) & VGA_RSRC_LEGACY_IO)
282 pci_bits |= PCI_COMMAND_IO;
283
284 if (pci_bits) {
285 vga_irq_set_state(conflict, false);
286 flags |= PCI_VGA_STATE_CHANGE_DECODES;
287 }
288 }
289
290 if (change_bridge)
291 flags |= PCI_VGA_STATE_CHANGE_BRIDGE;
292
293 pci_set_vga_state(conflict->pdev, false, pci_bits, flags);
294 conflict->owns &= ~match;
295
296 /* If we disabled normal decoding, reflect it in owns */
297 if (pci_bits & PCI_COMMAND_MEMORY)
298 conflict->owns &= ~VGA_RSRC_NORMAL_MEM;
299 if (pci_bits & PCI_COMMAND_IO)
300 conflict->owns &= ~VGA_RSRC_NORMAL_IO;
301 }
302
303enable_them:
304 /* ok dude, we got it, everybody conflicting has been disabled, let's
305 * enable us. Mark any bits in "owns" regardless of whether we
306 * decoded them. We can lock resources we don't decode, therefore
307 * we must track them via "owns".
308 */
309 flags = 0;
310 pci_bits = 0;
311
312 if (!vgadev->bridge_has_one_vga) {
313 flags |= PCI_VGA_STATE_CHANGE_DECODES;
314 if (wants & (VGA_RSRC_LEGACY_MEM|VGA_RSRC_NORMAL_MEM))
315 pci_bits |= PCI_COMMAND_MEMORY;
316 if (wants & (VGA_RSRC_LEGACY_IO|VGA_RSRC_NORMAL_IO))
317 pci_bits |= PCI_COMMAND_IO;
318 }
319 if (wants & VGA_RSRC_LEGACY_MASK)
320 flags |= PCI_VGA_STATE_CHANGE_BRIDGE;
321
322 pci_set_vga_state(vgadev->pdev, true, pci_bits, flags);
323
324 if (!vgadev->bridge_has_one_vga)
325 vga_irq_set_state(vgadev, true);
326
327 vgadev->owns |= wants;
328lock_them:
329 vgadev->locks |= (rsrc & VGA_RSRC_LEGACY_MASK);
330 if (rsrc & VGA_RSRC_LEGACY_IO)
331 vgadev->io_lock_cnt++;
332 if (rsrc & VGA_RSRC_LEGACY_MEM)
333 vgadev->mem_lock_cnt++;
334 if (rsrc & VGA_RSRC_NORMAL_IO)
335 vgadev->io_norm_cnt++;
336 if (rsrc & VGA_RSRC_NORMAL_MEM)
337 vgadev->mem_norm_cnt++;
338
339 return NULL;
340}
341
342static void __vga_put(struct vga_device *vgadev, unsigned int rsrc)
343{
344 struct device *dev = &vgadev->pdev->dev;
345 unsigned int old_locks = vgadev->locks;
346
347 vgaarb_dbg(dev, "%s\n", __func__);
348
349 /* Update our counters, and account for equivalent legacy resources
350 * if we decode them
351 */
352 if ((rsrc & VGA_RSRC_NORMAL_IO) && vgadev->io_norm_cnt > 0) {
353 vgadev->io_norm_cnt--;
354 if (vgadev->decodes & VGA_RSRC_LEGACY_IO)
355 rsrc |= VGA_RSRC_LEGACY_IO;
356 }
357 if ((rsrc & VGA_RSRC_NORMAL_MEM) && vgadev->mem_norm_cnt > 0) {
358 vgadev->mem_norm_cnt--;
359 if (vgadev->decodes & VGA_RSRC_LEGACY_MEM)
360 rsrc |= VGA_RSRC_LEGACY_MEM;
361 }
362 if ((rsrc & VGA_RSRC_LEGACY_IO) && vgadev->io_lock_cnt > 0)
363 vgadev->io_lock_cnt--;
364 if ((rsrc & VGA_RSRC_LEGACY_MEM) && vgadev->mem_lock_cnt > 0)
365 vgadev->mem_lock_cnt--;
366
367 /* Just clear lock bits, we do lazy operations so we don't really
368 * have to bother about anything else at this point
369 */
370 if (vgadev->io_lock_cnt == 0)
371 vgadev->locks &= ~VGA_RSRC_LEGACY_IO;
372 if (vgadev->mem_lock_cnt == 0)
373 vgadev->locks &= ~VGA_RSRC_LEGACY_MEM;
374
375 /* Kick the wait queue in case somebody was waiting if we actually
376 * released something
377 */
378 if (old_locks != vgadev->locks)
379 wake_up_all(&vga_wait_queue);
380}
381
382/**
383 * vga_get - acquire & locks VGA resources
384 * @pdev: pci device of the VGA card or NULL for the system default
385 * @rsrc: bit mask of resources to acquire and lock
386 * @interruptible: blocking should be interruptible by signals ?
387 *
388 * This function acquires VGA resources for the given card and mark those
389 * resources locked. If the resource requested are "normal" (and not legacy)
390 * resources, the arbiter will first check whether the card is doing legacy
391 * decoding for that type of resource. If yes, the lock is "converted" into a
392 * legacy resource lock.
393 *
394 * The arbiter will first look for all VGA cards that might conflict and disable
395 * their IOs and/or Memory access, including VGA forwarding on P2P bridges if
396 * necessary, so that the requested resources can be used. Then, the card is
397 * marked as locking these resources and the IO and/or Memory accesses are
398 * enabled on the card (including VGA forwarding on parent P2P bridges if any).
399 *
400 * This function will block if some conflicting card is already locking one of
401 * the required resources (or any resource on a different bus segment, since P2P
402 * bridges don't differentiate VGA memory and IO afaik). You can indicate
403 * whether this blocking should be interruptible by a signal (for userland
404 * interface) or not.
405 *
406 * Must not be called at interrupt time or in atomic context. If the card
407 * already owns the resources, the function succeeds. Nested calls are
408 * supported (a per-resource counter is maintained)
409 *
410 * On success, release the VGA resource again with vga_put().
411 *
412 * Returns:
413 *
414 * 0 on success, negative error code on failure.
415 */
416int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible)
417{
418 struct vga_device *vgadev, *conflict;
419 unsigned long flags;
420 wait_queue_t wait;
421 int rc = 0;
422
423 vga_check_first_use();
424 /* The one who calls us should check for this, but lets be sure... */
425 if (pdev == NULL)
426 pdev = vga_default_device();
427 if (pdev == NULL)
428 return 0;
429
430 for (;;) {
431 spin_lock_irqsave(&vga_lock, flags);
432 vgadev = vgadev_find(pdev);
433 if (vgadev == NULL) {
434 spin_unlock_irqrestore(&vga_lock, flags);
435 rc = -ENODEV;
436 break;
437 }
438 conflict = __vga_tryget(vgadev, rsrc);
439 spin_unlock_irqrestore(&vga_lock, flags);
440 if (conflict == NULL)
441 break;
442
443
444 /* We have a conflict, we wait until somebody kicks the
445 * work queue. Currently we have one work queue that we
446 * kick each time some resources are released, but it would
447 * be fairly easy to have a per device one so that we only
448 * need to attach to the conflicting device
449 */
450 init_waitqueue_entry(&wait, current);
451 add_wait_queue(&vga_wait_queue, &wait);
452 set_current_state(interruptible ?
453 TASK_INTERRUPTIBLE :
454 TASK_UNINTERRUPTIBLE);
455 if (interruptible && signal_pending(current)) {
456 __set_current_state(TASK_RUNNING);
457 remove_wait_queue(&vga_wait_queue, &wait);
458 rc = -ERESTARTSYS;
459 break;
460 }
461 schedule();
462 remove_wait_queue(&vga_wait_queue, &wait);
463 }
464 return rc;
465}
466EXPORT_SYMBOL(vga_get);
467
468/**
469 * vga_tryget - try to acquire & lock legacy VGA resources
470 * @pdev: pci devivce of VGA card or NULL for system default
471 * @rsrc: bit mask of resources to acquire and lock
472 *
473 * This function performs the same operation as vga_get(), but will return an
474 * error (-EBUSY) instead of blocking if the resources are already locked by
475 * another card. It can be called in any context
476 *
477 * On success, release the VGA resource again with vga_put().
478 *
479 * Returns:
480 *
481 * 0 on success, negative error code on failure.
482 */
483int vga_tryget(struct pci_dev *pdev, unsigned int rsrc)
484{
485 struct vga_device *vgadev;
486 unsigned long flags;
487 int rc = 0;
488
489 vga_check_first_use();
490
491 /* The one who calls us should check for this, but lets be sure... */
492 if (pdev == NULL)
493 pdev = vga_default_device();
494 if (pdev == NULL)
495 return 0;
496 spin_lock_irqsave(&vga_lock, flags);
497 vgadev = vgadev_find(pdev);
498 if (vgadev == NULL) {
499 rc = -ENODEV;
500 goto bail;
501 }
502 if (__vga_tryget(vgadev, rsrc))
503 rc = -EBUSY;
504bail:
505 spin_unlock_irqrestore(&vga_lock, flags);
506 return rc;
507}
508EXPORT_SYMBOL(vga_tryget);
509
510/**
511 * vga_put - release lock on legacy VGA resources
512 * @pdev: pci device of VGA card or NULL for system default
513 * @rsrc: but mask of resource to release
514 *
515 * This fuction releases resources previously locked by vga_get() or
516 * vga_tryget(). The resources aren't disabled right away, so that a subsequence
517 * vga_get() on the same card will succeed immediately. Resources have a
518 * counter, so locks are only released if the counter reaches 0.
519 */
520void vga_put(struct pci_dev *pdev, unsigned int rsrc)
521{
522 struct vga_device *vgadev;
523 unsigned long flags;
524
525 /* The one who calls us should check for this, but lets be sure... */
526 if (pdev == NULL)
527 pdev = vga_default_device();
528 if (pdev == NULL)
529 return;
530 spin_lock_irqsave(&vga_lock, flags);
531 vgadev = vgadev_find(pdev);
532 if (vgadev == NULL)
533 goto bail;
534 __vga_put(vgadev, rsrc);
535bail:
536 spin_unlock_irqrestore(&vga_lock, flags);
537}
538EXPORT_SYMBOL(vga_put);
539
540/*
541 * Rules for using a bridge to control a VGA descendant decoding: if a bridge
542 * has only one VGA descendant then it can be used to control the VGA routing
543 * for that device. It should always use the bridge closest to the device to
544 * control it. If a bridge has a direct VGA descendant, but also have a sub-
545 * bridge VGA descendant then we cannot use that bridge to control the direct
546 * VGA descendant. So for every device we register, we need to iterate all
547 * its parent bridges so we can invalidate any devices using them properly.
548 */
549static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev)
550{
551 struct vga_device *same_bridge_vgadev;
552 struct pci_bus *new_bus, *bus;
553 struct pci_dev *new_bridge, *bridge;
554
555 vgadev->bridge_has_one_vga = true;
556
557 if (list_empty(&vga_list))
558 return;
559
560 /* okay iterate the new devices bridge hierarachy */
561 new_bus = vgadev->pdev->bus;
562 while (new_bus) {
563 new_bridge = new_bus->self;
564
565 /* go through list of devices already registered */
566 list_for_each_entry(same_bridge_vgadev, &vga_list, list) {
567 bus = same_bridge_vgadev->pdev->bus;
568 bridge = bus->self;
569
570 /* see if the share a bridge with this device */
571 if (new_bridge == bridge) {
572 /*
573 * If their direct parent bridge is the same
574 * as any bridge of this device then it can't
575 * be used for that device.
576 */
577 same_bridge_vgadev->bridge_has_one_vga = false;
578 }
579
580 /*
581 * Now iterate the previous devices bridge hierarchy.
582 * If the new devices parent bridge is in the other
583 * devices hierarchy then we can't use it to control
584 * this device
585 */
586 while (bus) {
587 bridge = bus->self;
588
589 if (bridge && bridge == vgadev->pdev->bus->self)
590 vgadev->bridge_has_one_vga = false;
591
592 bus = bus->parent;
593 }
594 }
595 new_bus = new_bus->parent;
596 }
597}
598
599/*
600 * Currently, we assume that the "initial" setup of the system is
601 * not sane, that is we come up with conflicting devices and let
602 * the arbiter's client decides if devices decodes or not legacy
603 * things.
604 */
605static bool vga_arbiter_add_pci_device(struct pci_dev *pdev)
606{
607 struct vga_device *vgadev;
608 unsigned long flags;
609 struct pci_bus *bus;
610 struct pci_dev *bridge;
611 u16 cmd;
612
613 /* Only deal with VGA class devices */
614 if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
615 return false;
616
617 /* Allocate structure */
618 vgadev = kzalloc(sizeof(struct vga_device), GFP_KERNEL);
619 if (vgadev == NULL) {
620 vgaarb_err(&pdev->dev, "failed to allocate VGA arbiter data\n");
621 /*
622 * What to do on allocation failure ? For now, let's just do
623 * nothing, I'm not sure there is anything saner to be done.
624 */
625 return false;
626 }
627
628 /* Take lock & check for duplicates */
629 spin_lock_irqsave(&vga_lock, flags);
630 if (vgadev_find(pdev) != NULL) {
631 BUG_ON(1);
632 goto fail;
633 }
634 vgadev->pdev = pdev;
635
636 /* By default, assume we decode everything */
637 vgadev->decodes = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM |
638 VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
639
640 /* by default mark it as decoding */
641 vga_decode_count++;
642 /* Mark that we "own" resources based on our enables, we will
643 * clear that below if the bridge isn't forwarding
644 */
645 pci_read_config_word(pdev, PCI_COMMAND, &cmd);
646 if (cmd & PCI_COMMAND_IO)
647 vgadev->owns |= VGA_RSRC_LEGACY_IO;
648 if (cmd & PCI_COMMAND_MEMORY)
649 vgadev->owns |= VGA_RSRC_LEGACY_MEM;
650
651 /* Check if VGA cycles can get down to us */
652 bus = pdev->bus;
653 while (bus) {
654 bridge = bus->self;
655 if (bridge) {
656 u16 l;
657
658 pci_read_config_word(bridge, PCI_BRIDGE_CONTROL, &l);
659 if (!(l & PCI_BRIDGE_CTL_VGA)) {
660 vgadev->owns = 0;
661 break;
662 }
663 }
664 bus = bus->parent;
665 }
666
667 /* Deal with VGA default device. Use first enabled one
668 * by default if arch doesn't have it's own hook
669 */
670 if (vga_default == NULL &&
671 ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) {
672 vgaarb_info(&pdev->dev, "setting as boot VGA device\n");
673 vga_set_default_device(pdev);
674 }
675
676 vga_arbiter_check_bridge_sharing(vgadev);
677
678 /* Add to the list */
679 list_add(&vgadev->list, &vga_list);
680 vga_count++;
681 vgaarb_info(&pdev->dev, "VGA device added: decodes=%s,owns=%s,locks=%s\n",
682 vga_iostate_to_str(vgadev->decodes),
683 vga_iostate_to_str(vgadev->owns),
684 vga_iostate_to_str(vgadev->locks));
685
686 spin_unlock_irqrestore(&vga_lock, flags);
687 return true;
688fail:
689 spin_unlock_irqrestore(&vga_lock, flags);
690 kfree(vgadev);
691 return false;
692}
693
694static bool vga_arbiter_del_pci_device(struct pci_dev *pdev)
695{
696 struct vga_device *vgadev;
697 unsigned long flags;
698 bool ret = true;
699
700 spin_lock_irqsave(&vga_lock, flags);
701 vgadev = vgadev_find(pdev);
702 if (vgadev == NULL) {
703 ret = false;
704 goto bail;
705 }
706
707 if (vga_default == pdev)
708 vga_set_default_device(NULL);
709
710 if (vgadev->decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM))
711 vga_decode_count--;
712
713 /* Remove entry from list */
714 list_del(&vgadev->list);
715 vga_count--;
716 /* Notify userland driver that the device is gone so it discards
717 * it's copies of the pci_dev pointer
718 */
719 vga_arb_device_card_gone(pdev);
720
721 /* Wake up all possible waiters */
722 wake_up_all(&vga_wait_queue);
723bail:
724 spin_unlock_irqrestore(&vga_lock, flags);
725 kfree(vgadev);
726 return ret;
727}
728
729/* this is called with the lock */
730static inline void vga_update_device_decodes(struct vga_device *vgadev,
731 int new_decodes)
732{
733 struct device *dev = &vgadev->pdev->dev;
734 int old_decodes, decodes_removed, decodes_unlocked;
735
736 old_decodes = vgadev->decodes;
737 decodes_removed = ~new_decodes & old_decodes;
738 decodes_unlocked = vgadev->locks & decodes_removed;
739 vgadev->decodes = new_decodes;
740
741 vgaarb_info(dev, "changed VGA decodes: olddecodes=%s,decodes=%s:owns=%s\n",
742 vga_iostate_to_str(old_decodes),
743 vga_iostate_to_str(vgadev->decodes),
744 vga_iostate_to_str(vgadev->owns));
745
746 /* if we removed locked decodes, lock count goes to zero, and release */
747 if (decodes_unlocked) {
748 if (decodes_unlocked & VGA_RSRC_LEGACY_IO)
749 vgadev->io_lock_cnt = 0;
750 if (decodes_unlocked & VGA_RSRC_LEGACY_MEM)
751 vgadev->mem_lock_cnt = 0;
752 __vga_put(vgadev, decodes_unlocked);
753 }
754
755 /* change decodes counter */
756 if (old_decodes & VGA_RSRC_LEGACY_MASK &&
757 !(new_decodes & VGA_RSRC_LEGACY_MASK))
758 vga_decode_count--;
759 if (!(old_decodes & VGA_RSRC_LEGACY_MASK) &&
760 new_decodes & VGA_RSRC_LEGACY_MASK)
761 vga_decode_count++;
762 vgaarb_dbg(dev, "decoding count now is: %d\n", vga_decode_count);
763}
764
765static void __vga_set_legacy_decoding(struct pci_dev *pdev,
766 unsigned int decodes,
767 bool userspace)
768{
769 struct vga_device *vgadev;
770 unsigned long flags;
771
772 decodes &= VGA_RSRC_LEGACY_MASK;
773
774 spin_lock_irqsave(&vga_lock, flags);
775 vgadev = vgadev_find(pdev);
776 if (vgadev == NULL)
777 goto bail;
778
779 /* don't let userspace futz with kernel driver decodes */
780 if (userspace && vgadev->set_vga_decode)
781 goto bail;
782
783 /* update the device decodes + counter */
784 vga_update_device_decodes(vgadev, decodes);
785
786 /* XXX if somebody is going from "doesn't decode" to "decodes" state
787 * here, additional care must be taken as we may have pending owner
788 * ship of non-legacy region ...
789 */
790bail:
791 spin_unlock_irqrestore(&vga_lock, flags);
792}
793
794void vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes)
795{
796 __vga_set_legacy_decoding(pdev, decodes, false);
797}
798EXPORT_SYMBOL(vga_set_legacy_decoding);
799
800/**
801 * vga_client_register - register or unregister a VGA arbitration client
802 * @pdev: pci device of the VGA client
803 * @cookie: client cookie to be used in callbacks
804 * @irq_set_state: irq state change callback
805 * @set_vga_decode: vga decode change callback
806 *
807 * Clients have two callback mechanisms they can use.
808 *
809 * @irq_set_state callback: If a client can't disable its GPUs VGA
810 * resources, then we need to be able to ask it to turn off its irqs when we
811 * turn off its mem and io decoding.
812 *
813 * @set_vga_decode callback: If a client can disable its GPU VGA resource, it
814 * will get a callback from this to set the encode/decode state.
815 *
816 * Rationale: we cannot disable VGA decode resources unconditionally some single
817 * GPU laptops seem to require ACPI or BIOS access to the VGA registers to
818 * control things like backlights etc. Hopefully newer multi-GPU laptops do
819 * something saner, and desktops won't have any special ACPI for this. The
820 * driver will get a callback when VGA arbitration is first used by userspace
821 * since some older X servers have issues.
822 *
823 * This function does not check whether a client for @pdev has been registered
824 * already.
825 *
826 * To unregister just call this function with @irq_set_state and @set_vga_decode
827 * both set to NULL for the same @pdev as originally used to register them.
828 *
829 * Returns: 0 on success, -1 on failure
830 */
831int vga_client_register(struct pci_dev *pdev, void *cookie,
832 void (*irq_set_state)(void *cookie, bool state),
833 unsigned int (*set_vga_decode)(void *cookie,
834 bool decode))
835{
836 int ret = -ENODEV;
837 struct vga_device *vgadev;
838 unsigned long flags;
839
840 spin_lock_irqsave(&vga_lock, flags);
841 vgadev = vgadev_find(pdev);
842 if (!vgadev)
843 goto bail;
844
845 vgadev->irq_set_state = irq_set_state;
846 vgadev->set_vga_decode = set_vga_decode;
847 vgadev->cookie = cookie;
848 ret = 0;
849
850bail:
851 spin_unlock_irqrestore(&vga_lock, flags);
852 return ret;
853
854}
855EXPORT_SYMBOL(vga_client_register);
856
857/*
858 * Char driver implementation
859 *
860 * Semantics is:
861 *
862 * open : open user instance of the arbitrer. by default, it's
863 * attached to the default VGA device of the system.
864 *
865 * close : close user instance, release locks
866 *
867 * read : return a string indicating the status of the target.
868 * an IO state string is of the form {io,mem,io+mem,none},
869 * mc and ic are respectively mem and io lock counts (for
870 * debugging/diagnostic only). "decodes" indicate what the
871 * card currently decodes, "owns" indicates what is currently
872 * enabled on it, and "locks" indicates what is locked by this
873 * card. If the card is unplugged, we get "invalid" then for
874 * card_ID and an -ENODEV error is returned for any command
875 * until a new card is targeted
876 *
877 * "<card_ID>,decodes=<io_state>,owns=<io_state>,locks=<io_state> (ic,mc)"
878 *
879 * write : write a command to the arbiter. List of commands is:
880 *
881 * target <card_ID> : switch target to card <card_ID> (see below)
882 * lock <io_state> : acquires locks on target ("none" is invalid io_state)
883 * trylock <io_state> : non-blocking acquire locks on target
884 * unlock <io_state> : release locks on target
885 * unlock all : release all locks on target held by this user
886 * decodes <io_state> : set the legacy decoding attributes for the card
887 *
888 * poll : event if something change on any card (not just the target)
889 *
890 * card_ID is of the form "PCI:domain:bus:dev.fn". It can be set to "default"
891 * to go back to the system default card (TODO: not implemented yet).
892 * Currently, only PCI is supported as a prefix, but the userland API may
893 * support other bus types in the future, even if the current kernel
894 * implementation doesn't.
895 *
896 * Note about locks:
897 *
898 * The driver keeps track of which user has what locks on which card. It
899 * supports stacking, like the kernel one. This complexifies the implementation
900 * a bit, but makes the arbiter more tolerant to userspace problems and able
901 * to properly cleanup in all cases when a process dies.
902 * Currently, a max of 16 cards simultaneously can have locks issued from
903 * userspace for a given user (file descriptor instance) of the arbiter.
904 *
905 * If the device is hot-unplugged, there is a hook inside the module to notify
906 * they being added/removed in the system and automatically added/removed in
907 * the arbiter.
908 */
909
910#define MAX_USER_CARDS CONFIG_VGA_ARB_MAX_GPUS
911#define PCI_INVALID_CARD ((struct pci_dev *)-1UL)
912
913/*
914 * Each user has an array of these, tracking which cards have locks
915 */
916struct vga_arb_user_card {
917 struct pci_dev *pdev;
918 unsigned int mem_cnt;
919 unsigned int io_cnt;
920};
921
922struct vga_arb_private {
923 struct list_head list;
924 struct pci_dev *target;
925 struct vga_arb_user_card cards[MAX_USER_CARDS];
926 spinlock_t lock;
927};
928
929static LIST_HEAD(vga_user_list);
930static DEFINE_SPINLOCK(vga_user_lock);
931
932
933/*
934 * This function gets a string in the format: "PCI:domain:bus:dev.fn" and
935 * returns the respective values. If the string is not in this format,
936 * it returns 0.
937 */
938static int vga_pci_str_to_vars(char *buf, int count, unsigned int *domain,
939 unsigned int *bus, unsigned int *devfn)
940{
941 int n;
942 unsigned int slot, func;
943
944
945 n = sscanf(buf, "PCI:%x:%x:%x.%x", domain, bus, &slot, &func);
946 if (n != 4)
947 return 0;
948
949 *devfn = PCI_DEVFN(slot, func);
950
951 return 1;
952}
953
954static ssize_t vga_arb_read(struct file *file, char __user *buf,
955 size_t count, loff_t *ppos)
956{
957 struct vga_arb_private *priv = file->private_data;
958 struct vga_device *vgadev;
959 struct pci_dev *pdev;
960 unsigned long flags;
961 size_t len;
962 int rc;
963 char *lbuf;
964
965 lbuf = kmalloc(1024, GFP_KERNEL);
966 if (lbuf == NULL)
967 return -ENOMEM;
968
969 /* Shields against vga_arb_device_card_gone (pci_dev going
970 * away), and allows access to vga list
971 */
972 spin_lock_irqsave(&vga_lock, flags);
973
974 /* If we are targeting the default, use it */
975 pdev = priv->target;
976 if (pdev == NULL || pdev == PCI_INVALID_CARD) {
977 spin_unlock_irqrestore(&vga_lock, flags);
978 len = sprintf(lbuf, "invalid");
979 goto done;
980 }
981
982 /* Find card vgadev structure */
983 vgadev = vgadev_find(pdev);
984 if (vgadev == NULL) {
985 /* Wow, it's not in the list, that shouldn't happen,
986 * let's fix us up and return invalid card
987 */
988 if (pdev == priv->target)
989 vga_arb_device_card_gone(pdev);
990 spin_unlock_irqrestore(&vga_lock, flags);
991 len = sprintf(lbuf, "invalid");
992 goto done;
993 }
994
995 /* Fill the buffer with infos */
996 len = snprintf(lbuf, 1024,
997 "count:%d,PCI:%s,decodes=%s,owns=%s,locks=%s(%d:%d)\n",
998 vga_decode_count, pci_name(pdev),
999 vga_iostate_to_str(vgadev->decodes),
1000 vga_iostate_to_str(vgadev->owns),
1001 vga_iostate_to_str(vgadev->locks),
1002 vgadev->io_lock_cnt, vgadev->mem_lock_cnt);
1003
1004 spin_unlock_irqrestore(&vga_lock, flags);
1005done:
1006
1007 /* Copy that to user */
1008 if (len > count)
1009 len = count;
1010 rc = copy_to_user(buf, lbuf, len);
1011 kfree(lbuf);
1012 if (rc)
1013 return -EFAULT;
1014 return len;
1015}
1016
1017/*
1018 * TODO: To avoid parsing inside kernel and to improve the speed we may
1019 * consider use ioctl here
1020 */
1021static ssize_t vga_arb_write(struct file *file, const char __user *buf,
1022 size_t count, loff_t *ppos)
1023{
1024 struct vga_arb_private *priv = file->private_data;
1025 struct vga_arb_user_card *uc = NULL;
1026 struct pci_dev *pdev;
1027
1028 unsigned int io_state;
1029
1030 char kbuf[64], *curr_pos;
1031 size_t remaining = count;
1032
1033 int ret_val;
1034 int i;
1035
1036 if (count >= sizeof(kbuf))
1037 return -EINVAL;
1038 if (copy_from_user(kbuf, buf, count))
1039 return -EFAULT;
1040 curr_pos = kbuf;
1041 kbuf[count] = '\0'; /* Just to make sure... */
1042
1043 if (strncmp(curr_pos, "lock ", 5) == 0) {
1044 curr_pos += 5;
1045 remaining -= 5;
1046
1047 pr_debug("client 0x%p called 'lock'\n", priv);
1048
1049 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) {
1050 ret_val = -EPROTO;
1051 goto done;
1052 }
1053 if (io_state == VGA_RSRC_NONE) {
1054 ret_val = -EPROTO;
1055 goto done;
1056 }
1057
1058 pdev = priv->target;
1059 if (priv->target == NULL) {
1060 ret_val = -ENODEV;
1061 goto done;
1062 }
1063
1064 vga_get_uninterruptible(pdev, io_state);
1065
1066 /* Update the client's locks lists... */
1067 for (i = 0; i < MAX_USER_CARDS; i++) {
1068 if (priv->cards[i].pdev == pdev) {
1069 if (io_state & VGA_RSRC_LEGACY_IO)
1070 priv->cards[i].io_cnt++;
1071 if (io_state & VGA_RSRC_LEGACY_MEM)
1072 priv->cards[i].mem_cnt++;
1073 break;
1074 }
1075 }
1076
1077 ret_val = count;
1078 goto done;
1079 } else if (strncmp(curr_pos, "unlock ", 7) == 0) {
1080 curr_pos += 7;
1081 remaining -= 7;
1082
1083 pr_debug("client 0x%p called 'unlock'\n", priv);
1084
1085 if (strncmp(curr_pos, "all", 3) == 0)
1086 io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM;
1087 else {
1088 if (!vga_str_to_iostate
1089 (curr_pos, remaining, &io_state)) {
1090 ret_val = -EPROTO;
1091 goto done;
1092 }
1093 /* TODO: Add this?
1094 if (io_state == VGA_RSRC_NONE) {
1095 ret_val = -EPROTO;
1096 goto done;
1097 }
1098 */
1099 }
1100
1101 pdev = priv->target;
1102 if (priv->target == NULL) {
1103 ret_val = -ENODEV;
1104 goto done;
1105 }
1106 for (i = 0; i < MAX_USER_CARDS; i++) {
1107 if (priv->cards[i].pdev == pdev)
1108 uc = &priv->cards[i];
1109 }
1110
1111 if (!uc) {
1112 ret_val = -EINVAL;
1113 goto done;
1114 }
1115
1116 if (io_state & VGA_RSRC_LEGACY_IO && uc->io_cnt == 0) {
1117 ret_val = -EINVAL;
1118 goto done;
1119 }
1120
1121 if (io_state & VGA_RSRC_LEGACY_MEM && uc->mem_cnt == 0) {
1122 ret_val = -EINVAL;
1123 goto done;
1124 }
1125
1126 vga_put(pdev, io_state);
1127
1128 if (io_state & VGA_RSRC_LEGACY_IO)
1129 uc->io_cnt--;
1130 if (io_state & VGA_RSRC_LEGACY_MEM)
1131 uc->mem_cnt--;
1132
1133 ret_val = count;
1134 goto done;
1135 } else if (strncmp(curr_pos, "trylock ", 8) == 0) {
1136 curr_pos += 8;
1137 remaining -= 8;
1138
1139 pr_debug("client 0x%p called 'trylock'\n", priv);
1140
1141 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) {
1142 ret_val = -EPROTO;
1143 goto done;
1144 }
1145 /* TODO: Add this?
1146 if (io_state == VGA_RSRC_NONE) {
1147 ret_val = -EPROTO;
1148 goto done;
1149 }
1150 */
1151
1152 pdev = priv->target;
1153 if (priv->target == NULL) {
1154 ret_val = -ENODEV;
1155 goto done;
1156 }
1157
1158 if (vga_tryget(pdev, io_state)) {
1159 /* Update the client's locks lists... */
1160 for (i = 0; i < MAX_USER_CARDS; i++) {
1161 if (priv->cards[i].pdev == pdev) {
1162 if (io_state & VGA_RSRC_LEGACY_IO)
1163 priv->cards[i].io_cnt++;
1164 if (io_state & VGA_RSRC_LEGACY_MEM)
1165 priv->cards[i].mem_cnt++;
1166 break;
1167 }
1168 }
1169 ret_val = count;
1170 goto done;
1171 } else {
1172 ret_val = -EBUSY;
1173 goto done;
1174 }
1175
1176 } else if (strncmp(curr_pos, "target ", 7) == 0) {
1177 unsigned int domain, bus, devfn;
1178 struct vga_device *vgadev;
1179
1180 curr_pos += 7;
1181 remaining -= 7;
1182 pr_debug("client 0x%p called 'target'\n", priv);
1183 /* if target is default */
1184 if (!strncmp(curr_pos, "default", 7))
1185 pdev = pci_dev_get(vga_default_device());
1186 else {
1187 if (!vga_pci_str_to_vars(curr_pos, remaining,
1188 &domain, &bus, &devfn)) {
1189 ret_val = -EPROTO;
1190 goto done;
1191 }
1192 pdev = pci_get_domain_bus_and_slot(domain, bus, devfn);
1193 if (!pdev) {
1194 pr_debug("invalid PCI address %04x:%02x:%02x.%x\n",
1195 domain, bus, PCI_SLOT(devfn),
1196 PCI_FUNC(devfn));
1197 ret_val = -ENODEV;
1198 goto done;
1199 }
1200
1201 pr_debug("%s ==> %04x:%02x:%02x.%x pdev %p\n", curr_pos,
1202 domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn),
1203 pdev);
1204 }
1205
1206 vgadev = vgadev_find(pdev);
1207 pr_debug("vgadev %p\n", vgadev);
1208 if (vgadev == NULL) {
1209 if (pdev) {
1210 vgaarb_dbg(&pdev->dev, "not a VGA device\n");
1211 pci_dev_put(pdev);
1212 }
1213
1214 ret_val = -ENODEV;
1215 goto done;
1216 }
1217
1218 priv->target = pdev;
1219 for (i = 0; i < MAX_USER_CARDS; i++) {
1220 if (priv->cards[i].pdev == pdev)
1221 break;
1222 if (priv->cards[i].pdev == NULL) {
1223 priv->cards[i].pdev = pdev;
1224 priv->cards[i].io_cnt = 0;
1225 priv->cards[i].mem_cnt = 0;
1226 break;
1227 }
1228 }
1229 if (i == MAX_USER_CARDS) {
1230 vgaarb_dbg(&pdev->dev, "maximum user cards (%d) number reached, ignoring this one!\n",
1231 MAX_USER_CARDS);
1232 pci_dev_put(pdev);
1233 /* XXX: which value to return? */
1234 ret_val = -ENOMEM;
1235 goto done;
1236 }
1237
1238 ret_val = count;
1239 pci_dev_put(pdev);
1240 goto done;
1241
1242
1243 } else if (strncmp(curr_pos, "decodes ", 8) == 0) {
1244 curr_pos += 8;
1245 remaining -= 8;
1246 pr_debug("client 0x%p called 'decodes'\n", priv);
1247
1248 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) {
1249 ret_val = -EPROTO;
1250 goto done;
1251 }
1252 pdev = priv->target;
1253 if (priv->target == NULL) {
1254 ret_val = -ENODEV;
1255 goto done;
1256 }
1257
1258 __vga_set_legacy_decoding(pdev, io_state, true);
1259 ret_val = count;
1260 goto done;
1261 }
1262 /* If we got here, the message written is not part of the protocol! */
1263 return -EPROTO;
1264
1265done:
1266 return ret_val;
1267}
1268
1269static unsigned int vga_arb_fpoll(struct file *file, poll_table *wait)
1270{
1271 pr_debug("%s\n", __func__);
1272
1273 poll_wait(file, &vga_wait_queue, wait);
1274 return POLLIN;
1275}
1276
1277static int vga_arb_open(struct inode *inode, struct file *file)
1278{
1279 struct vga_arb_private *priv;
1280 unsigned long flags;
1281
1282 pr_debug("%s\n", __func__);
1283
1284 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
1285 if (priv == NULL)
1286 return -ENOMEM;
1287 spin_lock_init(&priv->lock);
1288 file->private_data = priv;
1289
1290 spin_lock_irqsave(&vga_user_lock, flags);
1291 list_add(&priv->list, &vga_user_list);
1292 spin_unlock_irqrestore(&vga_user_lock, flags);
1293
1294 /* Set the client' lists of locks */
1295 priv->target = vga_default_device(); /* Maybe this is still null! */
1296 priv->cards[0].pdev = priv->target;
1297 priv->cards[0].io_cnt = 0;
1298 priv->cards[0].mem_cnt = 0;
1299
1300
1301 return 0;
1302}
1303
1304static int vga_arb_release(struct inode *inode, struct file *file)
1305{
1306 struct vga_arb_private *priv = file->private_data;
1307 struct vga_arb_user_card *uc;
1308 unsigned long flags;
1309 int i;
1310
1311 pr_debug("%s\n", __func__);
1312
1313 spin_lock_irqsave(&vga_user_lock, flags);
1314 list_del(&priv->list);
1315 for (i = 0; i < MAX_USER_CARDS; i++) {
1316 uc = &priv->cards[i];
1317 if (uc->pdev == NULL)
1318 continue;
1319 vgaarb_dbg(&uc->pdev->dev, "uc->io_cnt == %d, uc->mem_cnt == %d\n",
1320 uc->io_cnt, uc->mem_cnt);
1321 while (uc->io_cnt--)
1322 vga_put(uc->pdev, VGA_RSRC_LEGACY_IO);
1323 while (uc->mem_cnt--)
1324 vga_put(uc->pdev, VGA_RSRC_LEGACY_MEM);
1325 }
1326 spin_unlock_irqrestore(&vga_user_lock, flags);
1327
1328 kfree(priv);
1329
1330 return 0;
1331}
1332
1333static void vga_arb_device_card_gone(struct pci_dev *pdev)
1334{
1335}
1336
1337/*
1338 * callback any registered clients to let them know we have a
1339 * change in VGA cards
1340 */
1341static void vga_arbiter_notify_clients(void)
1342{
1343 struct vga_device *vgadev;
1344 unsigned long flags;
1345 uint32_t new_decodes;
1346 bool new_state;
1347
1348 if (!vga_arbiter_used)
1349 return;
1350
1351 spin_lock_irqsave(&vga_lock, flags);
1352 list_for_each_entry(vgadev, &vga_list, list) {
1353 if (vga_count > 1)
1354 new_state = false;
1355 else
1356 new_state = true;
1357 if (vgadev->set_vga_decode) {
1358 new_decodes = vgadev->set_vga_decode(vgadev->cookie,
1359 new_state);
1360 vga_update_device_decodes(vgadev, new_decodes);
1361 }
1362 }
1363 spin_unlock_irqrestore(&vga_lock, flags);
1364}
1365
1366static int pci_notify(struct notifier_block *nb, unsigned long action,
1367 void *data)
1368{
1369 struct device *dev = data;
1370 struct pci_dev *pdev = to_pci_dev(dev);
1371 bool notify = false;
1372
1373 vgaarb_dbg(dev, "%s\n", __func__);
1374
1375 /* For now we're only intereted in devices added and removed. I didn't
1376 * test this thing here, so someone needs to double check for the
1377 * cases of hotplugable vga cards. */
1378 if (action == BUS_NOTIFY_ADD_DEVICE)
1379 notify = vga_arbiter_add_pci_device(pdev);
1380 else if (action == BUS_NOTIFY_DEL_DEVICE)
1381 notify = vga_arbiter_del_pci_device(pdev);
1382
1383 if (notify)
1384 vga_arbiter_notify_clients();
1385 return 0;
1386}
1387
1388static struct notifier_block pci_notifier = {
1389 .notifier_call = pci_notify,
1390};
1391
1392static const struct file_operations vga_arb_device_fops = {
1393 .read = vga_arb_read,
1394 .write = vga_arb_write,
1395 .poll = vga_arb_fpoll,
1396 .open = vga_arb_open,
1397 .release = vga_arb_release,
1398 .llseek = noop_llseek,
1399};
1400
1401static struct miscdevice vga_arb_device = {
1402 MISC_DYNAMIC_MINOR, "vga_arbiter", &vga_arb_device_fops
1403};
1404
1405static int __init vga_arb_device_init(void)
1406{
1407 int rc;
1408 struct pci_dev *pdev;
1409 struct vga_device *vgadev;
1410
1411 rc = misc_register(&vga_arb_device);
1412 if (rc < 0)
1413 pr_err("error %d registering device\n", rc);
1414
1415 bus_register_notifier(&pci_bus_type, &pci_notifier);
1416
1417 /* We add all pci devices satisfying vga class in the arbiter by
1418 * default */
1419 pdev = NULL;
1420 while ((pdev =
1421 pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
1422 PCI_ANY_ID, pdev)) != NULL)
1423 vga_arbiter_add_pci_device(pdev);
1424
1425 list_for_each_entry(vgadev, &vga_list, list) {
1426 struct device *dev = &vgadev->pdev->dev;
1427#if defined(CONFIG_X86) || defined(CONFIG_IA64)
1428 /*
1429 * Override vga_arbiter_add_pci_device()'s I/O based detection
1430 * as it may take the wrong device (e.g. on Apple system under
1431 * EFI).
1432 *
1433 * Select the device owning the boot framebuffer if there is
1434 * one.
1435 */
1436 resource_size_t start, end, limit;
1437 unsigned long flags;
1438 int i;
1439
1440 limit = screen_info.lfb_base + screen_info.lfb_size;
1441
1442 /* Does firmware framebuffer belong to us? */
1443 for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
1444 flags = pci_resource_flags(vgadev->pdev, i);
1445
1446 if ((flags & IORESOURCE_MEM) == 0)
1447 continue;
1448
1449 start = pci_resource_start(vgadev->pdev, i);
1450 end = pci_resource_end(vgadev->pdev, i);
1451
1452 if (!start || !end)
1453 continue;
1454
1455 if (screen_info.lfb_base < start || limit >= end)
1456 continue;
1457
1458 if (!vga_default_device())
1459 vgaarb_info(dev, "setting as boot device\n");
1460 else if (vgadev->pdev != vga_default_device())
1461 vgaarb_info(dev, "overriding boot device\n");
1462 vga_set_default_device(vgadev->pdev);
1463 }
1464#endif
1465 if (vgadev->bridge_has_one_vga)
1466 vgaarb_info(dev, "bridge control possible\n");
1467 else
1468 vgaarb_info(dev, "no bridge control possible\n");
1469 }
1470
1471 pr_info("loaded\n");
1472 return rc;
1473}
1474subsys_initcall(vga_arb_device_init);