Loading...
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#endif
140
141static inline void vga_irq_set_state(struct vga_device *vgadev, bool state)
142{
143 if (vgadev->irq_set_state)
144 vgadev->irq_set_state(vgadev->cookie, state);
145}
146
147
148/* If we don't ever use VGA arb we should avoid
149 turning off anything anywhere due to old X servers getting
150 confused about the boot device not being VGA */
151static void vga_check_first_use(void)
152{
153 /* we should inform all GPUs in the system that
154 * VGA arb has occurred and to try and disable resources
155 * if they can */
156 if (!vga_arbiter_used) {
157 vga_arbiter_used = true;
158 vga_arbiter_notify_clients();
159 }
160}
161
162static struct vga_device *__vga_tryget(struct vga_device *vgadev,
163 unsigned int rsrc)
164{
165 unsigned int wants, legacy_wants, match;
166 struct vga_device *conflict;
167 unsigned int pci_bits;
168 u32 flags = 0;
169
170 /* Account for "normal" resources to lock. If we decode the legacy,
171 * counterpart, we need to request it as well
172 */
173 if ((rsrc & VGA_RSRC_NORMAL_IO) &&
174 (vgadev->decodes & VGA_RSRC_LEGACY_IO))
175 rsrc |= VGA_RSRC_LEGACY_IO;
176 if ((rsrc & VGA_RSRC_NORMAL_MEM) &&
177 (vgadev->decodes & VGA_RSRC_LEGACY_MEM))
178 rsrc |= VGA_RSRC_LEGACY_MEM;
179
180 pr_debug("%s: %d\n", __func__, rsrc);
181 pr_debug("%s: owns: %d\n", __func__, vgadev->owns);
182
183 /* Check what resources we need to acquire */
184 wants = rsrc & ~vgadev->owns;
185
186 /* We already own everything, just mark locked & bye bye */
187 if (wants == 0)
188 goto lock_them;
189
190 /* We don't need to request a legacy resource, we just enable
191 * appropriate decoding and go
192 */
193 legacy_wants = wants & VGA_RSRC_LEGACY_MASK;
194 if (legacy_wants == 0)
195 goto enable_them;
196
197 /* Ok, we don't, let's find out how we need to kick off */
198 list_for_each_entry(conflict, &vga_list, list) {
199 unsigned int lwants = legacy_wants;
200 unsigned int change_bridge = 0;
201
202 /* Don't conflict with myself */
203 if (vgadev == conflict)
204 continue;
205
206 /* Check if the architecture allows a conflict between those
207 * 2 devices or if they are on separate domains
208 */
209 if (!vga_conflicts(vgadev->pdev, conflict->pdev))
210 continue;
211
212 /* We have a possible conflict. before we go further, we must
213 * check if we sit on the same bus as the conflicting device.
214 * if we don't, then we must tie both IO and MEM resources
215 * together since there is only a single bit controlling
216 * VGA forwarding on P2P bridges
217 */
218 if (vgadev->pdev->bus != conflict->pdev->bus) {
219 change_bridge = 1;
220 lwants = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM;
221 }
222
223 /* Check if the guy has a lock on the resource. If he does,
224 * return the conflicting entry
225 */
226 if (conflict->locks & lwants)
227 return conflict;
228
229 /* Ok, now check if he owns the resource we want. We don't need
230 * to check "decodes" since it should be impossible to own
231 * own legacy resources you don't decode unless I have a bug
232 * in this code...
233 */
234 WARN_ON(conflict->owns & ~conflict->decodes);
235 match = lwants & conflict->owns;
236 if (!match)
237 continue;
238
239 /* looks like he doesn't have a lock, we can steal
240 * them from him
241 */
242
243 flags = 0;
244 pci_bits = 0;
245
246 if (!conflict->bridge_has_one_vga) {
247 vga_irq_set_state(conflict, false);
248 flags |= PCI_VGA_STATE_CHANGE_DECODES;
249 if (lwants & (VGA_RSRC_LEGACY_MEM|VGA_RSRC_NORMAL_MEM))
250 pci_bits |= PCI_COMMAND_MEMORY;
251 if (lwants & (VGA_RSRC_LEGACY_IO|VGA_RSRC_NORMAL_IO))
252 pci_bits |= PCI_COMMAND_IO;
253 }
254
255 if (change_bridge)
256 flags |= PCI_VGA_STATE_CHANGE_BRIDGE;
257
258 pci_set_vga_state(conflict->pdev, false, pci_bits, flags);
259 conflict->owns &= ~lwants;
260 /* If he also owned non-legacy, that is no longer the case */
261 if (lwants & VGA_RSRC_LEGACY_MEM)
262 conflict->owns &= ~VGA_RSRC_NORMAL_MEM;
263 if (lwants & VGA_RSRC_LEGACY_IO)
264 conflict->owns &= ~VGA_RSRC_NORMAL_IO;
265 }
266
267enable_them:
268 /* ok dude, we got it, everybody conflicting has been disabled, let's
269 * enable us. Make sure we don't mark a bit in "owns" that we don't
270 * also have in "decodes". We can lock resources we don't decode but
271 * not own them.
272 */
273 flags = 0;
274 pci_bits = 0;
275
276 if (!vgadev->bridge_has_one_vga) {
277 flags |= PCI_VGA_STATE_CHANGE_DECODES;
278 if (wants & (VGA_RSRC_LEGACY_MEM|VGA_RSRC_NORMAL_MEM))
279 pci_bits |= PCI_COMMAND_MEMORY;
280 if (wants & (VGA_RSRC_LEGACY_IO|VGA_RSRC_NORMAL_IO))
281 pci_bits |= PCI_COMMAND_IO;
282 }
283 if (!!(wants & VGA_RSRC_LEGACY_MASK))
284 flags |= PCI_VGA_STATE_CHANGE_BRIDGE;
285
286 pci_set_vga_state(vgadev->pdev, true, pci_bits, flags);
287
288 if (!vgadev->bridge_has_one_vga) {
289 vga_irq_set_state(vgadev, true);
290 }
291 vgadev->owns |= (wants & vgadev->decodes);
292lock_them:
293 vgadev->locks |= (rsrc & VGA_RSRC_LEGACY_MASK);
294 if (rsrc & VGA_RSRC_LEGACY_IO)
295 vgadev->io_lock_cnt++;
296 if (rsrc & VGA_RSRC_LEGACY_MEM)
297 vgadev->mem_lock_cnt++;
298 if (rsrc & VGA_RSRC_NORMAL_IO)
299 vgadev->io_norm_cnt++;
300 if (rsrc & VGA_RSRC_NORMAL_MEM)
301 vgadev->mem_norm_cnt++;
302
303 return NULL;
304}
305
306static void __vga_put(struct vga_device *vgadev, unsigned int rsrc)
307{
308 unsigned int old_locks = vgadev->locks;
309
310 pr_debug("%s\n", __func__);
311
312 /* Update our counters, and account for equivalent legacy resources
313 * if we decode them
314 */
315 if ((rsrc & VGA_RSRC_NORMAL_IO) && vgadev->io_norm_cnt > 0) {
316 vgadev->io_norm_cnt--;
317 if (vgadev->decodes & VGA_RSRC_LEGACY_IO)
318 rsrc |= VGA_RSRC_LEGACY_IO;
319 }
320 if ((rsrc & VGA_RSRC_NORMAL_MEM) && vgadev->mem_norm_cnt > 0) {
321 vgadev->mem_norm_cnt--;
322 if (vgadev->decodes & VGA_RSRC_LEGACY_MEM)
323 rsrc |= VGA_RSRC_LEGACY_MEM;
324 }
325 if ((rsrc & VGA_RSRC_LEGACY_IO) && vgadev->io_lock_cnt > 0)
326 vgadev->io_lock_cnt--;
327 if ((rsrc & VGA_RSRC_LEGACY_MEM) && vgadev->mem_lock_cnt > 0)
328 vgadev->mem_lock_cnt--;
329
330 /* Just clear lock bits, we do lazy operations so we don't really
331 * have to bother about anything else at this point
332 */
333 if (vgadev->io_lock_cnt == 0)
334 vgadev->locks &= ~VGA_RSRC_LEGACY_IO;
335 if (vgadev->mem_lock_cnt == 0)
336 vgadev->locks &= ~VGA_RSRC_LEGACY_MEM;
337
338 /* Kick the wait queue in case somebody was waiting if we actually
339 * released something
340 */
341 if (old_locks != vgadev->locks)
342 wake_up_all(&vga_wait_queue);
343}
344
345int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible)
346{
347 struct vga_device *vgadev, *conflict;
348 unsigned long flags;
349 wait_queue_t wait;
350 int rc = 0;
351
352 vga_check_first_use();
353 /* The one who calls us should check for this, but lets be sure... */
354 if (pdev == NULL)
355 pdev = vga_default_device();
356 if (pdev == NULL)
357 return 0;
358
359 for (;;) {
360 spin_lock_irqsave(&vga_lock, flags);
361 vgadev = vgadev_find(pdev);
362 if (vgadev == NULL) {
363 spin_unlock_irqrestore(&vga_lock, flags);
364 rc = -ENODEV;
365 break;
366 }
367 conflict = __vga_tryget(vgadev, rsrc);
368 spin_unlock_irqrestore(&vga_lock, flags);
369 if (conflict == NULL)
370 break;
371
372
373 /* We have a conflict, we wait until somebody kicks the
374 * work queue. Currently we have one work queue that we
375 * kick each time some resources are released, but it would
376 * be fairly easy to have a per device one so that we only
377 * need to attach to the conflicting device
378 */
379 init_waitqueue_entry(&wait, current);
380 add_wait_queue(&vga_wait_queue, &wait);
381 set_current_state(interruptible ?
382 TASK_INTERRUPTIBLE :
383 TASK_UNINTERRUPTIBLE);
384 if (signal_pending(current)) {
385 rc = -EINTR;
386 break;
387 }
388 schedule();
389 remove_wait_queue(&vga_wait_queue, &wait);
390 set_current_state(TASK_RUNNING);
391 }
392 return rc;
393}
394EXPORT_SYMBOL(vga_get);
395
396int vga_tryget(struct pci_dev *pdev, unsigned int rsrc)
397{
398 struct vga_device *vgadev;
399 unsigned long flags;
400 int rc = 0;
401
402 vga_check_first_use();
403
404 /* The one who calls us should check for this, but lets be sure... */
405 if (pdev == NULL)
406 pdev = vga_default_device();
407 if (pdev == NULL)
408 return 0;
409 spin_lock_irqsave(&vga_lock, flags);
410 vgadev = vgadev_find(pdev);
411 if (vgadev == NULL) {
412 rc = -ENODEV;
413 goto bail;
414 }
415 if (__vga_tryget(vgadev, rsrc))
416 rc = -EBUSY;
417bail:
418 spin_unlock_irqrestore(&vga_lock, flags);
419 return rc;
420}
421EXPORT_SYMBOL(vga_tryget);
422
423void vga_put(struct pci_dev *pdev, unsigned int rsrc)
424{
425 struct vga_device *vgadev;
426 unsigned long flags;
427
428 /* The one who calls us should check for this, but lets be sure... */
429 if (pdev == NULL)
430 pdev = vga_default_device();
431 if (pdev == NULL)
432 return;
433 spin_lock_irqsave(&vga_lock, flags);
434 vgadev = vgadev_find(pdev);
435 if (vgadev == NULL)
436 goto bail;
437 __vga_put(vgadev, rsrc);
438bail:
439 spin_unlock_irqrestore(&vga_lock, flags);
440}
441EXPORT_SYMBOL(vga_put);
442
443/* Rules for using a bridge to control a VGA descendant decoding:
444 if a bridge has only one VGA descendant then it can be used
445 to control the VGA routing for that device.
446 It should always use the bridge closest to the device to control it.
447 If a bridge has a direct VGA descendant, but also have a sub-bridge
448 VGA descendant then we cannot use that bridge to control the direct VGA descendant.
449 So for every device we register, we need to iterate all its parent bridges
450 so we can invalidate any devices using them properly.
451*/
452static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev)
453{
454 struct vga_device *same_bridge_vgadev;
455 struct pci_bus *new_bus, *bus;
456 struct pci_dev *new_bridge, *bridge;
457
458 vgadev->bridge_has_one_vga = true;
459
460 if (list_empty(&vga_list))
461 return;
462
463 /* okay iterate the new devices bridge hierarachy */
464 new_bus = vgadev->pdev->bus;
465 while (new_bus) {
466 new_bridge = new_bus->self;
467
468 if (new_bridge) {
469 /* go through list of devices already registered */
470 list_for_each_entry(same_bridge_vgadev, &vga_list, list) {
471 bus = same_bridge_vgadev->pdev->bus;
472 bridge = bus->self;
473
474 /* see if the share a bridge with this device */
475 if (new_bridge == bridge) {
476 /* if their direct parent bridge is the same
477 as any bridge of this device then it can't be used
478 for that device */
479 same_bridge_vgadev->bridge_has_one_vga = false;
480 }
481
482 /* now iterate the previous devices bridge hierarchy */
483 /* if the new devices parent bridge is in the other devices
484 hierarchy then we can't use it to control this device */
485 while (bus) {
486 bridge = bus->self;
487 if (bridge) {
488 if (bridge == vgadev->pdev->bus->self)
489 vgadev->bridge_has_one_vga = false;
490 }
491 bus = bus->parent;
492 }
493 }
494 }
495 new_bus = new_bus->parent;
496 }
497}
498
499/*
500 * Currently, we assume that the "initial" setup of the system is
501 * not sane, that is we come up with conflicting devices and let
502 * the arbiter's client decides if devices decodes or not legacy
503 * things.
504 */
505static bool vga_arbiter_add_pci_device(struct pci_dev *pdev)
506{
507 struct vga_device *vgadev;
508 unsigned long flags;
509 struct pci_bus *bus;
510 struct pci_dev *bridge;
511 u16 cmd;
512
513 /* Only deal with VGA class devices */
514 if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
515 return false;
516
517 /* Allocate structure */
518 vgadev = kmalloc(sizeof(struct vga_device), GFP_KERNEL);
519 if (vgadev == NULL) {
520 pr_err("vgaarb: failed to allocate pci device\n");
521 /* What to do on allocation failure ? For now, let's
522 * just do nothing, I'm not sure there is anything saner
523 * to be done
524 */
525 return false;
526 }
527
528 memset(vgadev, 0, sizeof(*vgadev));
529
530 /* Take lock & check for duplicates */
531 spin_lock_irqsave(&vga_lock, flags);
532 if (vgadev_find(pdev) != NULL) {
533 BUG_ON(1);
534 goto fail;
535 }
536 vgadev->pdev = pdev;
537
538 /* By default, assume we decode everything */
539 vgadev->decodes = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM |
540 VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
541
542 /* by default mark it as decoding */
543 vga_decode_count++;
544 /* Mark that we "own" resources based on our enables, we will
545 * clear that below if the bridge isn't forwarding
546 */
547 pci_read_config_word(pdev, PCI_COMMAND, &cmd);
548 if (cmd & PCI_COMMAND_IO)
549 vgadev->owns |= VGA_RSRC_LEGACY_IO;
550 if (cmd & PCI_COMMAND_MEMORY)
551 vgadev->owns |= VGA_RSRC_LEGACY_MEM;
552
553 /* Check if VGA cycles can get down to us */
554 bus = pdev->bus;
555 while (bus) {
556 bridge = bus->self;
557 if (bridge) {
558 u16 l;
559 pci_read_config_word(bridge, PCI_BRIDGE_CONTROL,
560 &l);
561 if (!(l & PCI_BRIDGE_CTL_VGA)) {
562 vgadev->owns = 0;
563 break;
564 }
565 }
566 bus = bus->parent;
567 }
568
569 /* Deal with VGA default device. Use first enabled one
570 * by default if arch doesn't have it's own hook
571 */
572#ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE
573 if (vga_default == NULL &&
574 ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK))
575 vga_default = pci_dev_get(pdev);
576#endif
577
578 vga_arbiter_check_bridge_sharing(vgadev);
579
580 /* Add to the list */
581 list_add(&vgadev->list, &vga_list);
582 vga_count++;
583 pr_info("vgaarb: device added: PCI:%s,decodes=%s,owns=%s,locks=%s\n",
584 pci_name(pdev),
585 vga_iostate_to_str(vgadev->decodes),
586 vga_iostate_to_str(vgadev->owns),
587 vga_iostate_to_str(vgadev->locks));
588
589 spin_unlock_irqrestore(&vga_lock, flags);
590 return true;
591fail:
592 spin_unlock_irqrestore(&vga_lock, flags);
593 kfree(vgadev);
594 return false;
595}
596
597static bool vga_arbiter_del_pci_device(struct pci_dev *pdev)
598{
599 struct vga_device *vgadev;
600 unsigned long flags;
601 bool ret = true;
602
603 spin_lock_irqsave(&vga_lock, flags);
604 vgadev = vgadev_find(pdev);
605 if (vgadev == NULL) {
606 ret = false;
607 goto bail;
608 }
609
610 if (vga_default == pdev) {
611 pci_dev_put(vga_default);
612 vga_default = NULL;
613 }
614
615 if (vgadev->decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM))
616 vga_decode_count--;
617
618 /* Remove entry from list */
619 list_del(&vgadev->list);
620 vga_count--;
621 /* Notify userland driver that the device is gone so it discards
622 * it's copies of the pci_dev pointer
623 */
624 vga_arb_device_card_gone(pdev);
625
626 /* Wake up all possible waiters */
627 wake_up_all(&vga_wait_queue);
628bail:
629 spin_unlock_irqrestore(&vga_lock, flags);
630 kfree(vgadev);
631 return ret;
632}
633
634/* this is called with the lock */
635static inline void vga_update_device_decodes(struct vga_device *vgadev,
636 int new_decodes)
637{
638 int old_decodes;
639 struct vga_device *new_vgadev, *conflict;
640
641 old_decodes = vgadev->decodes;
642 vgadev->decodes = new_decodes;
643
644 pr_info("vgaarb: device changed decodes: PCI:%s,olddecodes=%s,decodes=%s:owns=%s\n",
645 pci_name(vgadev->pdev),
646 vga_iostate_to_str(old_decodes),
647 vga_iostate_to_str(vgadev->decodes),
648 vga_iostate_to_str(vgadev->owns));
649
650
651 /* if we own the decodes we should move them along to
652 another card */
653 if ((vgadev->owns & old_decodes) && (vga_count > 1)) {
654 /* set us to own nothing */
655 vgadev->owns &= ~old_decodes;
656 list_for_each_entry(new_vgadev, &vga_list, list) {
657 if ((new_vgadev != vgadev) &&
658 (new_vgadev->decodes & VGA_RSRC_LEGACY_MASK)) {
659 pr_info("vgaarb: transferring owner from PCI:%s to PCI:%s\n", pci_name(vgadev->pdev), pci_name(new_vgadev->pdev));
660 conflict = __vga_tryget(new_vgadev, VGA_RSRC_LEGACY_MASK);
661 if (!conflict)
662 __vga_put(new_vgadev, VGA_RSRC_LEGACY_MASK);
663 break;
664 }
665 }
666 }
667
668 /* change decodes counter */
669 if (old_decodes != new_decodes) {
670 if (new_decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM))
671 vga_decode_count++;
672 else
673 vga_decode_count--;
674 }
675 pr_debug("vgaarb: decoding count now is: %d\n", vga_decode_count);
676}
677
678static void __vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes, bool userspace)
679{
680 struct vga_device *vgadev;
681 unsigned long flags;
682
683 decodes &= VGA_RSRC_LEGACY_MASK;
684
685 spin_lock_irqsave(&vga_lock, flags);
686 vgadev = vgadev_find(pdev);
687 if (vgadev == NULL)
688 goto bail;
689
690 /* don't let userspace futz with kernel driver decodes */
691 if (userspace && vgadev->set_vga_decode)
692 goto bail;
693
694 /* update the device decodes + counter */
695 vga_update_device_decodes(vgadev, decodes);
696
697 /* XXX if somebody is going from "doesn't decode" to "decodes" state
698 * here, additional care must be taken as we may have pending owner
699 * ship of non-legacy region ...
700 */
701bail:
702 spin_unlock_irqrestore(&vga_lock, flags);
703}
704
705void vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes)
706{
707 __vga_set_legacy_decoding(pdev, decodes, false);
708}
709EXPORT_SYMBOL(vga_set_legacy_decoding);
710
711/* call with NULL to unregister */
712int vga_client_register(struct pci_dev *pdev, void *cookie,
713 void (*irq_set_state)(void *cookie, bool state),
714 unsigned int (*set_vga_decode)(void *cookie, bool decode))
715{
716 int ret = -ENODEV;
717 struct vga_device *vgadev;
718 unsigned long flags;
719
720 spin_lock_irqsave(&vga_lock, flags);
721 vgadev = vgadev_find(pdev);
722 if (!vgadev)
723 goto bail;
724
725 vgadev->irq_set_state = irq_set_state;
726 vgadev->set_vga_decode = set_vga_decode;
727 vgadev->cookie = cookie;
728 ret = 0;
729
730bail:
731 spin_unlock_irqrestore(&vga_lock, flags);
732 return ret;
733
734}
735EXPORT_SYMBOL(vga_client_register);
736
737/*
738 * Char driver implementation
739 *
740 * Semantics is:
741 *
742 * open : open user instance of the arbitrer. by default, it's
743 * attached to the default VGA device of the system.
744 *
745 * close : close user instance, release locks
746 *
747 * read : return a string indicating the status of the target.
748 * an IO state string is of the form {io,mem,io+mem,none},
749 * mc and ic are respectively mem and io lock counts (for
750 * debugging/diagnostic only). "decodes" indicate what the
751 * card currently decodes, "owns" indicates what is currently
752 * enabled on it, and "locks" indicates what is locked by this
753 * card. If the card is unplugged, we get "invalid" then for
754 * card_ID and an -ENODEV error is returned for any command
755 * until a new card is targeted
756 *
757 * "<card_ID>,decodes=<io_state>,owns=<io_state>,locks=<io_state> (ic,mc)"
758 *
759 * write : write a command to the arbiter. List of commands is:
760 *
761 * target <card_ID> : switch target to card <card_ID> (see below)
762 * lock <io_state> : acquires locks on target ("none" is invalid io_state)
763 * trylock <io_state> : non-blocking acquire locks on target
764 * unlock <io_state> : release locks on target
765 * unlock all : release all locks on target held by this user
766 * decodes <io_state> : set the legacy decoding attributes for the card
767 *
768 * poll : event if something change on any card (not just the target)
769 *
770 * card_ID is of the form "PCI:domain:bus:dev.fn". It can be set to "default"
771 * to go back to the system default card (TODO: not implemented yet).
772 * Currently, only PCI is supported as a prefix, but the userland API may
773 * support other bus types in the future, even if the current kernel
774 * implementation doesn't.
775 *
776 * Note about locks:
777 *
778 * The driver keeps track of which user has what locks on which card. It
779 * supports stacking, like the kernel one. This complexifies the implementation
780 * a bit, but makes the arbiter more tolerant to userspace problems and able
781 * to properly cleanup in all cases when a process dies.
782 * Currently, a max of 16 cards simultaneously can have locks issued from
783 * userspace for a given user (file descriptor instance) of the arbiter.
784 *
785 * If the device is hot-unplugged, there is a hook inside the module to notify
786 * they being added/removed in the system and automatically added/removed in
787 * the arbiter.
788 */
789
790#define MAX_USER_CARDS CONFIG_VGA_ARB_MAX_GPUS
791#define PCI_INVALID_CARD ((struct pci_dev *)-1UL)
792
793/*
794 * Each user has an array of these, tracking which cards have locks
795 */
796struct vga_arb_user_card {
797 struct pci_dev *pdev;
798 unsigned int mem_cnt;
799 unsigned int io_cnt;
800};
801
802struct vga_arb_private {
803 struct list_head list;
804 struct pci_dev *target;
805 struct vga_arb_user_card cards[MAX_USER_CARDS];
806 spinlock_t lock;
807};
808
809static LIST_HEAD(vga_user_list);
810static DEFINE_SPINLOCK(vga_user_lock);
811
812
813/*
814 * This function gets a string in the format: "PCI:domain:bus:dev.fn" and
815 * returns the respective values. If the string is not in this format,
816 * it returns 0.
817 */
818static int vga_pci_str_to_vars(char *buf, int count, unsigned int *domain,
819 unsigned int *bus, unsigned int *devfn)
820{
821 int n;
822 unsigned int slot, func;
823
824
825 n = sscanf(buf, "PCI:%x:%x:%x.%x", domain, bus, &slot, &func);
826 if (n != 4)
827 return 0;
828
829 *devfn = PCI_DEVFN(slot, func);
830
831 return 1;
832}
833
834static ssize_t vga_arb_read(struct file *file, char __user * buf,
835 size_t count, loff_t *ppos)
836{
837 struct vga_arb_private *priv = file->private_data;
838 struct vga_device *vgadev;
839 struct pci_dev *pdev;
840 unsigned long flags;
841 size_t len;
842 int rc;
843 char *lbuf;
844
845 lbuf = kmalloc(1024, GFP_KERNEL);
846 if (lbuf == NULL)
847 return -ENOMEM;
848
849 /* Shields against vga_arb_device_card_gone (pci_dev going
850 * away), and allows access to vga list
851 */
852 spin_lock_irqsave(&vga_lock, flags);
853
854 /* If we are targeting the default, use it */
855 pdev = priv->target;
856 if (pdev == NULL || pdev == PCI_INVALID_CARD) {
857 spin_unlock_irqrestore(&vga_lock, flags);
858 len = sprintf(lbuf, "invalid");
859 goto done;
860 }
861
862 /* Find card vgadev structure */
863 vgadev = vgadev_find(pdev);
864 if (vgadev == NULL) {
865 /* Wow, it's not in the list, that shouldn't happen,
866 * let's fix us up and return invalid card
867 */
868 if (pdev == priv->target)
869 vga_arb_device_card_gone(pdev);
870 spin_unlock_irqrestore(&vga_lock, flags);
871 len = sprintf(lbuf, "invalid");
872 goto done;
873 }
874
875 /* Fill the buffer with infos */
876 len = snprintf(lbuf, 1024,
877 "count:%d,PCI:%s,decodes=%s,owns=%s,locks=%s(%d:%d)\n",
878 vga_decode_count, pci_name(pdev),
879 vga_iostate_to_str(vgadev->decodes),
880 vga_iostate_to_str(vgadev->owns),
881 vga_iostate_to_str(vgadev->locks),
882 vgadev->io_lock_cnt, vgadev->mem_lock_cnt);
883
884 spin_unlock_irqrestore(&vga_lock, flags);
885done:
886
887 /* Copy that to user */
888 if (len > count)
889 len = count;
890 rc = copy_to_user(buf, lbuf, len);
891 kfree(lbuf);
892 if (rc)
893 return -EFAULT;
894 return len;
895}
896
897/*
898 * TODO: To avoid parsing inside kernel and to improve the speed we may
899 * consider use ioctl here
900 */
901static ssize_t vga_arb_write(struct file *file, const char __user * buf,
902 size_t count, loff_t *ppos)
903{
904 struct vga_arb_private *priv = file->private_data;
905 struct vga_arb_user_card *uc = NULL;
906 struct pci_dev *pdev;
907
908 unsigned int io_state;
909
910 char *kbuf, *curr_pos;
911 size_t remaining = count;
912
913 int ret_val;
914 int i;
915
916
917 kbuf = kmalloc(count + 1, GFP_KERNEL);
918 if (!kbuf)
919 return -ENOMEM;
920
921 if (copy_from_user(kbuf, buf, count)) {
922 kfree(kbuf);
923 return -EFAULT;
924 }
925 curr_pos = kbuf;
926 kbuf[count] = '\0'; /* Just to make sure... */
927
928 if (strncmp(curr_pos, "lock ", 5) == 0) {
929 curr_pos += 5;
930 remaining -= 5;
931
932 pr_debug("client 0x%p called 'lock'\n", priv);
933
934 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) {
935 ret_val = -EPROTO;
936 goto done;
937 }
938 if (io_state == VGA_RSRC_NONE) {
939 ret_val = -EPROTO;
940 goto done;
941 }
942
943 pdev = priv->target;
944 if (priv->target == NULL) {
945 ret_val = -ENODEV;
946 goto done;
947 }
948
949 vga_get_uninterruptible(pdev, io_state);
950
951 /* Update the client's locks lists... */
952 for (i = 0; i < MAX_USER_CARDS; i++) {
953 if (priv->cards[i].pdev == pdev) {
954 if (io_state & VGA_RSRC_LEGACY_IO)
955 priv->cards[i].io_cnt++;
956 if (io_state & VGA_RSRC_LEGACY_MEM)
957 priv->cards[i].mem_cnt++;
958 break;
959 }
960 }
961
962 ret_val = count;
963 goto done;
964 } else if (strncmp(curr_pos, "unlock ", 7) == 0) {
965 curr_pos += 7;
966 remaining -= 7;
967
968 pr_debug("client 0x%p called 'unlock'\n", priv);
969
970 if (strncmp(curr_pos, "all", 3) == 0)
971 io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM;
972 else {
973 if (!vga_str_to_iostate
974 (curr_pos, remaining, &io_state)) {
975 ret_val = -EPROTO;
976 goto done;
977 }
978 /* TODO: Add this?
979 if (io_state == VGA_RSRC_NONE) {
980 ret_val = -EPROTO;
981 goto done;
982 }
983 */
984 }
985
986 pdev = priv->target;
987 if (priv->target == NULL) {
988 ret_val = -ENODEV;
989 goto done;
990 }
991 for (i = 0; i < MAX_USER_CARDS; i++) {
992 if (priv->cards[i].pdev == pdev)
993 uc = &priv->cards[i];
994 }
995
996 if (!uc)
997 return -EINVAL;
998
999 if (io_state & VGA_RSRC_LEGACY_IO && uc->io_cnt == 0)
1000 return -EINVAL;
1001
1002 if (io_state & VGA_RSRC_LEGACY_MEM && uc->mem_cnt == 0)
1003 return -EINVAL;
1004
1005 vga_put(pdev, io_state);
1006
1007 if (io_state & VGA_RSRC_LEGACY_IO)
1008 uc->io_cnt--;
1009 if (io_state & VGA_RSRC_LEGACY_MEM)
1010 uc->mem_cnt--;
1011
1012 ret_val = count;
1013 goto done;
1014 } else if (strncmp(curr_pos, "trylock ", 8) == 0) {
1015 curr_pos += 8;
1016 remaining -= 8;
1017
1018 pr_debug("client 0x%p called 'trylock'\n", priv);
1019
1020 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) {
1021 ret_val = -EPROTO;
1022 goto done;
1023 }
1024 /* TODO: Add this?
1025 if (io_state == VGA_RSRC_NONE) {
1026 ret_val = -EPROTO;
1027 goto done;
1028 }
1029 */
1030
1031 pdev = priv->target;
1032 if (priv->target == NULL) {
1033 ret_val = -ENODEV;
1034 goto done;
1035 }
1036
1037 if (vga_tryget(pdev, io_state)) {
1038 /* Update the client's locks lists... */
1039 for (i = 0; i < MAX_USER_CARDS; i++) {
1040 if (priv->cards[i].pdev == pdev) {
1041 if (io_state & VGA_RSRC_LEGACY_IO)
1042 priv->cards[i].io_cnt++;
1043 if (io_state & VGA_RSRC_LEGACY_MEM)
1044 priv->cards[i].mem_cnt++;
1045 break;
1046 }
1047 }
1048 ret_val = count;
1049 goto done;
1050 } else {
1051 ret_val = -EBUSY;
1052 goto done;
1053 }
1054
1055 } else if (strncmp(curr_pos, "target ", 7) == 0) {
1056 struct pci_bus *pbus;
1057 unsigned int domain, bus, devfn;
1058 struct vga_device *vgadev;
1059
1060 curr_pos += 7;
1061 remaining -= 7;
1062 pr_debug("client 0x%p called 'target'\n", priv);
1063 /* if target is default */
1064 if (!strncmp(curr_pos, "default", 7))
1065 pdev = pci_dev_get(vga_default_device());
1066 else {
1067 if (!vga_pci_str_to_vars(curr_pos, remaining,
1068 &domain, &bus, &devfn)) {
1069 ret_val = -EPROTO;
1070 goto done;
1071 }
1072 pr_debug("vgaarb: %s ==> %x:%x:%x.%x\n", curr_pos,
1073 domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn));
1074
1075 pbus = pci_find_bus(domain, bus);
1076 pr_debug("vgaarb: pbus %p\n", pbus);
1077 if (pbus == NULL) {
1078 pr_err("vgaarb: invalid PCI domain and/or bus address %x:%x\n",
1079 domain, bus);
1080 ret_val = -ENODEV;
1081 goto done;
1082 }
1083 pdev = pci_get_slot(pbus, devfn);
1084 pr_debug("vgaarb: pdev %p\n", pdev);
1085 if (!pdev) {
1086 pr_err("vgaarb: invalid PCI address %x:%x\n",
1087 bus, devfn);
1088 ret_val = -ENODEV;
1089 goto done;
1090 }
1091 }
1092
1093 vgadev = vgadev_find(pdev);
1094 pr_debug("vgaarb: vgadev %p\n", vgadev);
1095 if (vgadev == NULL) {
1096 pr_err("vgaarb: this pci device is not a vga device\n");
1097 pci_dev_put(pdev);
1098 ret_val = -ENODEV;
1099 goto done;
1100 }
1101
1102 priv->target = pdev;
1103 for (i = 0; i < MAX_USER_CARDS; i++) {
1104 if (priv->cards[i].pdev == pdev)
1105 break;
1106 if (priv->cards[i].pdev == NULL) {
1107 priv->cards[i].pdev = pdev;
1108 priv->cards[i].io_cnt = 0;
1109 priv->cards[i].mem_cnt = 0;
1110 break;
1111 }
1112 }
1113 if (i == MAX_USER_CARDS) {
1114 pr_err("vgaarb: maximum user cards (%d) number reached!\n",
1115 MAX_USER_CARDS);
1116 pci_dev_put(pdev);
1117 /* XXX: which value to return? */
1118 ret_val = -ENOMEM;
1119 goto done;
1120 }
1121
1122 ret_val = count;
1123 pci_dev_put(pdev);
1124 goto done;
1125
1126
1127 } else if (strncmp(curr_pos, "decodes ", 8) == 0) {
1128 curr_pos += 8;
1129 remaining -= 8;
1130 pr_debug("vgaarb: client 0x%p called 'decodes'\n", priv);
1131
1132 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) {
1133 ret_val = -EPROTO;
1134 goto done;
1135 }
1136 pdev = priv->target;
1137 if (priv->target == NULL) {
1138 ret_val = -ENODEV;
1139 goto done;
1140 }
1141
1142 __vga_set_legacy_decoding(pdev, io_state, true);
1143 ret_val = count;
1144 goto done;
1145 }
1146 /* If we got here, the message written is not part of the protocol! */
1147 kfree(kbuf);
1148 return -EPROTO;
1149
1150done:
1151 kfree(kbuf);
1152 return ret_val;
1153}
1154
1155static unsigned int vga_arb_fpoll(struct file *file, poll_table * wait)
1156{
1157 struct vga_arb_private *priv = file->private_data;
1158
1159 pr_debug("%s\n", __func__);
1160
1161 if (priv == NULL)
1162 return -ENODEV;
1163 poll_wait(file, &vga_wait_queue, wait);
1164 return POLLIN;
1165}
1166
1167static int vga_arb_open(struct inode *inode, struct file *file)
1168{
1169 struct vga_arb_private *priv;
1170 unsigned long flags;
1171
1172 pr_debug("%s\n", __func__);
1173
1174 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
1175 if (priv == NULL)
1176 return -ENOMEM;
1177 spin_lock_init(&priv->lock);
1178 file->private_data = priv;
1179
1180 spin_lock_irqsave(&vga_user_lock, flags);
1181 list_add(&priv->list, &vga_user_list);
1182 spin_unlock_irqrestore(&vga_user_lock, flags);
1183
1184 /* Set the client' lists of locks */
1185 priv->target = vga_default_device(); /* Maybe this is still null! */
1186 priv->cards[0].pdev = priv->target;
1187 priv->cards[0].io_cnt = 0;
1188 priv->cards[0].mem_cnt = 0;
1189
1190
1191 return 0;
1192}
1193
1194static int vga_arb_release(struct inode *inode, struct file *file)
1195{
1196 struct vga_arb_private *priv = file->private_data;
1197 struct vga_arb_user_card *uc;
1198 unsigned long flags;
1199 int i;
1200
1201 pr_debug("%s\n", __func__);
1202
1203 if (priv == NULL)
1204 return -ENODEV;
1205
1206 spin_lock_irqsave(&vga_user_lock, flags);
1207 list_del(&priv->list);
1208 for (i = 0; i < MAX_USER_CARDS; i++) {
1209 uc = &priv->cards[i];
1210 if (uc->pdev == NULL)
1211 continue;
1212 pr_debug("uc->io_cnt == %d, uc->mem_cnt == %d\n",
1213 uc->io_cnt, uc->mem_cnt);
1214 while (uc->io_cnt--)
1215 vga_put(uc->pdev, VGA_RSRC_LEGACY_IO);
1216 while (uc->mem_cnt--)
1217 vga_put(uc->pdev, VGA_RSRC_LEGACY_MEM);
1218 }
1219 spin_unlock_irqrestore(&vga_user_lock, flags);
1220
1221 kfree(priv);
1222
1223 return 0;
1224}
1225
1226static void vga_arb_device_card_gone(struct pci_dev *pdev)
1227{
1228}
1229
1230/*
1231 * callback any registered clients to let them know we have a
1232 * change in VGA cards
1233 */
1234static void vga_arbiter_notify_clients(void)
1235{
1236 struct vga_device *vgadev;
1237 unsigned long flags;
1238 uint32_t new_decodes;
1239 bool new_state;
1240
1241 if (!vga_arbiter_used)
1242 return;
1243
1244 spin_lock_irqsave(&vga_lock, flags);
1245 list_for_each_entry(vgadev, &vga_list, list) {
1246 if (vga_count > 1)
1247 new_state = false;
1248 else
1249 new_state = true;
1250 if (vgadev->set_vga_decode) {
1251 new_decodes = vgadev->set_vga_decode(vgadev->cookie, new_state);
1252 vga_update_device_decodes(vgadev, new_decodes);
1253 }
1254 }
1255 spin_unlock_irqrestore(&vga_lock, flags);
1256}
1257
1258static int pci_notify(struct notifier_block *nb, unsigned long action,
1259 void *data)
1260{
1261 struct device *dev = data;
1262 struct pci_dev *pdev = to_pci_dev(dev);
1263 bool notify = false;
1264
1265 pr_debug("%s\n", __func__);
1266
1267 /* For now we're only intereted in devices added and removed. I didn't
1268 * test this thing here, so someone needs to double check for the
1269 * cases of hotplugable vga cards. */
1270 if (action == BUS_NOTIFY_ADD_DEVICE)
1271 notify = vga_arbiter_add_pci_device(pdev);
1272 else if (action == BUS_NOTIFY_DEL_DEVICE)
1273 notify = vga_arbiter_del_pci_device(pdev);
1274
1275 if (notify)
1276 vga_arbiter_notify_clients();
1277 return 0;
1278}
1279
1280static struct notifier_block pci_notifier = {
1281 .notifier_call = pci_notify,
1282};
1283
1284static const struct file_operations vga_arb_device_fops = {
1285 .read = vga_arb_read,
1286 .write = vga_arb_write,
1287 .poll = vga_arb_fpoll,
1288 .open = vga_arb_open,
1289 .release = vga_arb_release,
1290 .llseek = noop_llseek,
1291};
1292
1293static struct miscdevice vga_arb_device = {
1294 MISC_DYNAMIC_MINOR, "vga_arbiter", &vga_arb_device_fops
1295};
1296
1297static int __init vga_arb_device_init(void)
1298{
1299 int rc;
1300 struct pci_dev *pdev;
1301 struct vga_device *vgadev;
1302
1303 rc = misc_register(&vga_arb_device);
1304 if (rc < 0)
1305 pr_err("vgaarb: error %d registering device\n", rc);
1306
1307 bus_register_notifier(&pci_bus_type, &pci_notifier);
1308
1309 /* We add all pci devices satisfying vga class in the arbiter by
1310 * default */
1311 pdev = NULL;
1312 while ((pdev =
1313 pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
1314 PCI_ANY_ID, pdev)) != NULL)
1315 vga_arbiter_add_pci_device(pdev);
1316
1317 pr_info("vgaarb: loaded\n");
1318
1319 list_for_each_entry(vgadev, &vga_list, list) {
1320 if (vgadev->bridge_has_one_vga)
1321 pr_info("vgaarb: bridge control possible %s\n", pci_name(vgadev->pdev));
1322 else
1323 pr_info("vgaarb: no bridge control possible %s\n", pci_name(vgadev->pdev));
1324 }
1325 return rc;
1326}
1327subsys_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/signal.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_entry_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 __poll_t 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 EPOLLIN;
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 void __init vga_arb_select_default_device(void)
1406{
1407 struct pci_dev *pdev;
1408 struct vga_device *vgadev;
1409
1410#if defined(CONFIG_X86) || defined(CONFIG_IA64)
1411 list_for_each_entry(vgadev, &vga_list, list) {
1412 struct device *dev = &vgadev->pdev->dev;
1413 /*
1414 * Override vga_arbiter_add_pci_device()'s I/O based detection
1415 * as it may take the wrong device (e.g. on Apple system under
1416 * EFI).
1417 *
1418 * Select the device owning the boot framebuffer if there is
1419 * one.
1420 */
1421 resource_size_t start, end, limit;
1422 unsigned long flags;
1423 int i;
1424
1425 limit = screen_info.lfb_base + screen_info.lfb_size;
1426
1427 /* Does firmware framebuffer belong to us? */
1428 for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
1429 flags = pci_resource_flags(vgadev->pdev, i);
1430
1431 if ((flags & IORESOURCE_MEM) == 0)
1432 continue;
1433
1434 start = pci_resource_start(vgadev->pdev, i);
1435 end = pci_resource_end(vgadev->pdev, i);
1436
1437 if (!start || !end)
1438 continue;
1439
1440 if (screen_info.lfb_base < start || limit >= end)
1441 continue;
1442
1443 if (!vga_default_device())
1444 vgaarb_info(dev, "setting as boot device\n");
1445 else if (vgadev->pdev != vga_default_device())
1446 vgaarb_info(dev, "overriding boot device\n");
1447 vga_set_default_device(vgadev->pdev);
1448 }
1449 }
1450#endif
1451
1452 if (!vga_default_device()) {
1453 list_for_each_entry(vgadev, &vga_list, list) {
1454 struct device *dev = &vgadev->pdev->dev;
1455 u16 cmd;
1456
1457 pdev = vgadev->pdev;
1458 pci_read_config_word(pdev, PCI_COMMAND, &cmd);
1459 if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) {
1460 vgaarb_info(dev, "setting as boot device (VGA legacy resources not available)\n");
1461 vga_set_default_device(pdev);
1462 break;
1463 }
1464 }
1465 }
1466
1467 if (!vga_default_device()) {
1468 vgadev = list_first_entry_or_null(&vga_list,
1469 struct vga_device, list);
1470 if (vgadev) {
1471 struct device *dev = &vgadev->pdev->dev;
1472 vgaarb_info(dev, "setting as boot device (VGA legacy resources not available)\n");
1473 vga_set_default_device(vgadev->pdev);
1474 }
1475 }
1476}
1477
1478static int __init vga_arb_device_init(void)
1479{
1480 int rc;
1481 struct pci_dev *pdev;
1482 struct vga_device *vgadev;
1483
1484 rc = misc_register(&vga_arb_device);
1485 if (rc < 0)
1486 pr_err("error %d registering device\n", rc);
1487
1488 bus_register_notifier(&pci_bus_type, &pci_notifier);
1489
1490 /* We add all PCI devices satisfying VGA class in the arbiter by
1491 * default */
1492 pdev = NULL;
1493 while ((pdev =
1494 pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
1495 PCI_ANY_ID, pdev)) != NULL)
1496 vga_arbiter_add_pci_device(pdev);
1497
1498 list_for_each_entry(vgadev, &vga_list, list) {
1499 struct device *dev = &vgadev->pdev->dev;
1500
1501 if (vgadev->bridge_has_one_vga)
1502 vgaarb_info(dev, "bridge control possible\n");
1503 else
1504 vgaarb_info(dev, "no bridge control possible\n");
1505 }
1506
1507 vga_arb_select_default_device();
1508
1509 pr_info("loaded\n");
1510 return rc;
1511}
1512subsys_initcall(vga_arb_device_init);