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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);