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