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1// SPDX-License-Identifier: MIT
2/*
3 * vgaarb.c: Implements VGA arbitration. For details refer to
4 * Documentation/gpu/vgaarbiter.rst
5 *
6 * (C) Copyright 2005 Benjamin Herrenschmidt <[email protected]>
7 * (C) Copyright 2007 Paulo R. Zanoni <[email protected]>
8 * (C) Copyright 2007, 2009 Tiago Vignatti <[email protected]>
9 */
10
11#define pr_fmt(fmt) "vgaarb: " fmt
12
13#define vgaarb_dbg(dev, fmt, arg...) dev_dbg(dev, "vgaarb: " fmt, ##arg)
14#define vgaarb_info(dev, fmt, arg...) dev_info(dev, "vgaarb: " fmt, ##arg)
15#define vgaarb_err(dev, fmt, arg...) dev_err(dev, "vgaarb: " fmt, ##arg)
16
17#include <linux/module.h>
18#include <linux/kernel.h>
19#include <linux/pci.h>
20#include <linux/errno.h>
21#include <linux/init.h>
22#include <linux/list.h>
23#include <linux/sched/signal.h>
24#include <linux/wait.h>
25#include <linux/spinlock.h>
26#include <linux/poll.h>
27#include <linux/miscdevice.h>
28#include <linux/slab.h>
29#include <linux/sysfb.h>
30#include <linux/vt.h>
31#include <linux/console.h>
32#include <linux/acpi.h>
33#include <linux/uaccess.h>
34#include <linux/vgaarb.h>
35
36static void vga_arbiter_notify_clients(void);
37
38/*
39 * We keep a list of all VGA devices in the system to speed
40 * up the various operations of the arbiter
41 */
42struct vga_device {
43 struct list_head list;
44 struct pci_dev *pdev;
45 unsigned int decodes; /* what it decodes */
46 unsigned int owns; /* what it owns */
47 unsigned int locks; /* what it locks */
48 unsigned int io_lock_cnt; /* legacy IO lock count */
49 unsigned int mem_lock_cnt; /* legacy MEM lock count */
50 unsigned int io_norm_cnt; /* normal IO count */
51 unsigned int mem_norm_cnt; /* normal MEM count */
52 bool bridge_has_one_vga;
53 bool is_firmware_default; /* device selected by firmware */
54 unsigned int (*set_decode)(struct pci_dev *pdev, bool decode);
55};
56
57static LIST_HEAD(vga_list);
58static int vga_count, vga_decode_count;
59static bool vga_arbiter_used;
60static DEFINE_SPINLOCK(vga_lock);
61static DECLARE_WAIT_QUEUE_HEAD(vga_wait_queue);
62
63static const char *vga_iostate_to_str(unsigned int iostate)
64{
65 /* Ignore VGA_RSRC_IO and VGA_RSRC_MEM */
66 iostate &= VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM;
67 switch (iostate) {
68 case VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM:
69 return "io+mem";
70 case VGA_RSRC_LEGACY_IO:
71 return "io";
72 case VGA_RSRC_LEGACY_MEM:
73 return "mem";
74 }
75 return "none";
76}
77
78static int vga_str_to_iostate(char *buf, int str_size, unsigned int *io_state)
79{
80 /*
81 * In theory, we could hand out locks on IO and MEM separately to
82 * userspace, but this can cause deadlocks.
83 */
84 if (strncmp(buf, "none", 4) == 0) {
85 *io_state = VGA_RSRC_NONE;
86 return 1;
87 }
88
89 /* XXX We're not checking the str_size! */
90 if (strncmp(buf, "io+mem", 6) == 0)
91 goto both;
92 else if (strncmp(buf, "io", 2) == 0)
93 goto both;
94 else if (strncmp(buf, "mem", 3) == 0)
95 goto both;
96 return 0;
97both:
98 *io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM;
99 return 1;
100}
101
102/* This is only used as a cookie, it should not be dereferenced */
103static struct pci_dev *vga_default;
104
105/* Find somebody in our list */
106static struct vga_device *vgadev_find(struct pci_dev *pdev)
107{
108 struct vga_device *vgadev;
109
110 list_for_each_entry(vgadev, &vga_list, list)
111 if (pdev == vgadev->pdev)
112 return vgadev;
113 return NULL;
114}
115
116/**
117 * vga_default_device - return the default VGA device, for vgacon
118 *
119 * This can be defined by the platform. The default implementation is
120 * rather dumb and will probably only work properly on single VGA card
121 * setups and/or x86 platforms.
122 *
123 * If your VGA default device is not PCI, you'll have to return NULL here.
124 * In this case, I assume it will not conflict with any PCI card. If this
125 * is not true, I'll have to define two arch hooks for enabling/disabling
126 * the VGA default device if that is possible. This may be a problem with
127 * real _ISA_ VGA cards, in addition to a PCI one. I don't know at this
128 * point how to deal with that card. Can their IOs be disabled at all? If
129 * not, then I suppose it's a matter of having the proper arch hook telling
130 * us about it, so we basically never allow anybody to succeed a vga_get().
131 */
132struct pci_dev *vga_default_device(void)
133{
134 return vga_default;
135}
136EXPORT_SYMBOL_GPL(vga_default_device);
137
138void vga_set_default_device(struct pci_dev *pdev)
139{
140 if (vga_default == pdev)
141 return;
142
143 pci_dev_put(vga_default);
144 vga_default = pci_dev_get(pdev);
145}
146
147/**
148 * vga_remove_vgacon - deactivate VGA console
149 *
150 * Unbind and unregister vgacon in case pdev is the default VGA device.
151 * Can be called by GPU drivers on initialization to make sure VGA register
152 * access done by vgacon will not disturb the device.
153 *
154 * @pdev: PCI device.
155 */
156#if !defined(CONFIG_VGA_CONSOLE)
157int vga_remove_vgacon(struct pci_dev *pdev)
158{
159 return 0;
160}
161#elif !defined(CONFIG_DUMMY_CONSOLE)
162int vga_remove_vgacon(struct pci_dev *pdev)
163{
164 return -ENODEV;
165}
166#else
167int vga_remove_vgacon(struct pci_dev *pdev)
168{
169 int ret = 0;
170
171 if (pdev != vga_default)
172 return 0;
173 vgaarb_info(&pdev->dev, "deactivate vga console\n");
174
175 console_lock();
176 if (con_is_bound(&vga_con))
177 ret = do_take_over_console(&dummy_con, 0,
178 MAX_NR_CONSOLES - 1, 1);
179 if (ret == 0) {
180 ret = do_unregister_con_driver(&vga_con);
181
182 /* Ignore "already unregistered". */
183 if (ret == -ENODEV)
184 ret = 0;
185 }
186 console_unlock();
187
188 return ret;
189}
190#endif
191EXPORT_SYMBOL(vga_remove_vgacon);
192
193/*
194 * If we don't ever use VGA arbitration, we should avoid turning off
195 * anything anywhere due to old X servers getting confused about the boot
196 * device not being VGA.
197 */
198static void vga_check_first_use(void)
199{
200 /*
201 * Inform all GPUs in the system that VGA arbitration has occurred
202 * so they can disable resources if possible.
203 */
204 if (!vga_arbiter_used) {
205 vga_arbiter_used = true;
206 vga_arbiter_notify_clients();
207 }
208}
209
210static struct vga_device *__vga_tryget(struct vga_device *vgadev,
211 unsigned int rsrc)
212{
213 struct device *dev = &vgadev->pdev->dev;
214 unsigned int wants, legacy_wants, match;
215 struct vga_device *conflict;
216 unsigned int pci_bits;
217 u32 flags = 0;
218 int err;
219
220 /*
221 * Account for "normal" resources to lock. If we decode the legacy,
222 * counterpart, we need to request it as well
223 */
224 if ((rsrc & VGA_RSRC_NORMAL_IO) &&
225 (vgadev->decodes & VGA_RSRC_LEGACY_IO))
226 rsrc |= VGA_RSRC_LEGACY_IO;
227 if ((rsrc & VGA_RSRC_NORMAL_MEM) &&
228 (vgadev->decodes & VGA_RSRC_LEGACY_MEM))
229 rsrc |= VGA_RSRC_LEGACY_MEM;
230
231 vgaarb_dbg(dev, "%s: %d\n", __func__, rsrc);
232 vgaarb_dbg(dev, "%s: owns: %d\n", __func__, vgadev->owns);
233
234 /* Check what resources we need to acquire */
235 wants = rsrc & ~vgadev->owns;
236
237 /* We already own everything, just mark locked & bye bye */
238 if (wants == 0)
239 goto lock_them;
240
241 /*
242 * We don't need to request a legacy resource, we just enable
243 * appropriate decoding and go.
244 */
245 legacy_wants = wants & VGA_RSRC_LEGACY_MASK;
246 if (legacy_wants == 0)
247 goto enable_them;
248
249 /* Ok, we don't, let's find out who we need to kick off */
250 list_for_each_entry(conflict, &vga_list, list) {
251 unsigned int lwants = legacy_wants;
252 unsigned int change_bridge = 0;
253
254 /* Don't conflict with myself */
255 if (vgadev == conflict)
256 continue;
257
258 /*
259 * We have a possible conflict. Before we go further, we must
260 * check if we sit on the same bus as the conflicting device.
261 * If we don't, then we must tie both IO and MEM resources
262 * together since there is only a single bit controlling
263 * VGA forwarding on P2P bridges.
264 */
265 if (vgadev->pdev->bus != conflict->pdev->bus) {
266 change_bridge = 1;
267 lwants = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM;
268 }
269
270 /*
271 * Check if the guy has a lock on the resource. If he does,
272 * return the conflicting entry.
273 */
274 if (conflict->locks & lwants)
275 return conflict;
276
277 /*
278 * Ok, now check if it owns the resource we want. We can
279 * lock resources that are not decoded; therefore a device
280 * can own resources it doesn't decode.
281 */
282 match = lwants & conflict->owns;
283 if (!match)
284 continue;
285
286 /*
287 * Looks like he doesn't have a lock, we can steal them
288 * from him.
289 */
290
291 flags = 0;
292 pci_bits = 0;
293
294 /*
295 * If we can't control legacy resources via the bridge, we
296 * also need to disable normal decoding.
297 */
298 if (!conflict->bridge_has_one_vga) {
299 if ((match & conflict->decodes) & VGA_RSRC_LEGACY_MEM)
300 pci_bits |= PCI_COMMAND_MEMORY;
301 if ((match & conflict->decodes) & VGA_RSRC_LEGACY_IO)
302 pci_bits |= PCI_COMMAND_IO;
303
304 if (pci_bits)
305 flags |= PCI_VGA_STATE_CHANGE_DECODES;
306 }
307
308 if (change_bridge)
309 flags |= PCI_VGA_STATE_CHANGE_BRIDGE;
310
311 err = pci_set_vga_state(conflict->pdev, false, pci_bits, flags);
312 if (err)
313 return ERR_PTR(err);
314 conflict->owns &= ~match;
315
316 /* If we disabled normal decoding, reflect it in owns */
317 if (pci_bits & PCI_COMMAND_MEMORY)
318 conflict->owns &= ~VGA_RSRC_NORMAL_MEM;
319 if (pci_bits & PCI_COMMAND_IO)
320 conflict->owns &= ~VGA_RSRC_NORMAL_IO;
321 }
322
323enable_them:
324 /*
325 * Ok, we got it, everybody conflicting has been disabled, let's
326 * enable us. Mark any bits in "owns" regardless of whether we
327 * decoded them. We can lock resources we don't decode, therefore
328 * we must track them via "owns".
329 */
330 flags = 0;
331 pci_bits = 0;
332
333 if (!vgadev->bridge_has_one_vga) {
334 flags |= PCI_VGA_STATE_CHANGE_DECODES;
335 if (wants & (VGA_RSRC_LEGACY_MEM|VGA_RSRC_NORMAL_MEM))
336 pci_bits |= PCI_COMMAND_MEMORY;
337 if (wants & (VGA_RSRC_LEGACY_IO|VGA_RSRC_NORMAL_IO))
338 pci_bits |= PCI_COMMAND_IO;
339 }
340 if (wants & VGA_RSRC_LEGACY_MASK)
341 flags |= PCI_VGA_STATE_CHANGE_BRIDGE;
342
343 err = pci_set_vga_state(vgadev->pdev, true, pci_bits, flags);
344 if (err)
345 return ERR_PTR(err);
346
347 vgadev->owns |= wants;
348lock_them:
349 vgadev->locks |= (rsrc & VGA_RSRC_LEGACY_MASK);
350 if (rsrc & VGA_RSRC_LEGACY_IO)
351 vgadev->io_lock_cnt++;
352 if (rsrc & VGA_RSRC_LEGACY_MEM)
353 vgadev->mem_lock_cnt++;
354 if (rsrc & VGA_RSRC_NORMAL_IO)
355 vgadev->io_norm_cnt++;
356 if (rsrc & VGA_RSRC_NORMAL_MEM)
357 vgadev->mem_norm_cnt++;
358
359 return NULL;
360}
361
362static void __vga_put(struct vga_device *vgadev, unsigned int rsrc)
363{
364 struct device *dev = &vgadev->pdev->dev;
365 unsigned int old_locks = vgadev->locks;
366
367 vgaarb_dbg(dev, "%s\n", __func__);
368
369 /*
370 * Update our counters and account for equivalent legacy resources
371 * if we decode them.
372 */
373 if ((rsrc & VGA_RSRC_NORMAL_IO) && vgadev->io_norm_cnt > 0) {
374 vgadev->io_norm_cnt--;
375 if (vgadev->decodes & VGA_RSRC_LEGACY_IO)
376 rsrc |= VGA_RSRC_LEGACY_IO;
377 }
378 if ((rsrc & VGA_RSRC_NORMAL_MEM) && vgadev->mem_norm_cnt > 0) {
379 vgadev->mem_norm_cnt--;
380 if (vgadev->decodes & VGA_RSRC_LEGACY_MEM)
381 rsrc |= VGA_RSRC_LEGACY_MEM;
382 }
383 if ((rsrc & VGA_RSRC_LEGACY_IO) && vgadev->io_lock_cnt > 0)
384 vgadev->io_lock_cnt--;
385 if ((rsrc & VGA_RSRC_LEGACY_MEM) && vgadev->mem_lock_cnt > 0)
386 vgadev->mem_lock_cnt--;
387
388 /*
389 * Just clear lock bits, we do lazy operations so we don't really
390 * have to bother about anything else at this point.
391 */
392 if (vgadev->io_lock_cnt == 0)
393 vgadev->locks &= ~VGA_RSRC_LEGACY_IO;
394 if (vgadev->mem_lock_cnt == 0)
395 vgadev->locks &= ~VGA_RSRC_LEGACY_MEM;
396
397 /*
398 * Kick the wait queue in case somebody was waiting if we actually
399 * released something.
400 */
401 if (old_locks != vgadev->locks)
402 wake_up_all(&vga_wait_queue);
403}
404
405/**
406 * vga_get - acquire & lock VGA resources
407 * @pdev: PCI device of the VGA card or NULL for the system default
408 * @rsrc: bit mask of resources to acquire and lock
409 * @interruptible: blocking should be interruptible by signals ?
410 *
411 * Acquire VGA resources for the given card and mark those resources
412 * locked. If the resources requested are "normal" (and not legacy)
413 * resources, the arbiter will first check whether the card is doing legacy
414 * decoding for that type of resource. If yes, the lock is "converted" into
415 * a legacy resource lock.
416 *
417 * The arbiter will first look for all VGA cards that might conflict and disable
418 * their IOs and/or Memory access, including VGA forwarding on P2P bridges if
419 * necessary, so that the requested resources can be used. Then, the card is
420 * marked as locking these resources and the IO and/or Memory accesses are
421 * enabled on the card (including VGA forwarding on parent P2P bridges if any).
422 *
423 * This function will block if some conflicting card is already locking one of
424 * the required resources (or any resource on a different bus segment, since P2P
425 * bridges don't differentiate VGA memory and IO afaik). You can indicate
426 * whether this blocking should be interruptible by a signal (for userland
427 * interface) or not.
428 *
429 * Must not be called at interrupt time or in atomic context. If the card
430 * already owns the resources, the function succeeds. Nested calls are
431 * supported (a per-resource counter is maintained)
432 *
433 * On success, release the VGA resource again with vga_put().
434 *
435 * Returns:
436 *
437 * 0 on success, negative error code on failure.
438 */
439int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible)
440{
441 struct vga_device *vgadev, *conflict;
442 unsigned long flags;
443 wait_queue_entry_t wait;
444 int rc = 0;
445
446 vga_check_first_use();
447 /* The caller should check for this, but let's be sure */
448 if (pdev == NULL)
449 pdev = vga_default_device();
450 if (pdev == NULL)
451 return 0;
452
453 for (;;) {
454 spin_lock_irqsave(&vga_lock, flags);
455 vgadev = vgadev_find(pdev);
456 if (vgadev == NULL) {
457 spin_unlock_irqrestore(&vga_lock, flags);
458 rc = -ENODEV;
459 break;
460 }
461 conflict = __vga_tryget(vgadev, rsrc);
462 spin_unlock_irqrestore(&vga_lock, flags);
463 if (IS_ERR(conflict)) {
464 rc = PTR_ERR(conflict);
465 break;
466 }
467 if (conflict == NULL)
468 break;
469
470 /*
471 * We have a conflict; we wait until somebody kicks the
472 * work queue. Currently we have one work queue that we
473 * kick each time some resources are released, but it would
474 * be fairly easy to have a per-device one so that we only
475 * need to attach to the conflicting device.
476 */
477 init_waitqueue_entry(&wait, current);
478 add_wait_queue(&vga_wait_queue, &wait);
479 set_current_state(interruptible ?
480 TASK_INTERRUPTIBLE :
481 TASK_UNINTERRUPTIBLE);
482 if (interruptible && signal_pending(current)) {
483 __set_current_state(TASK_RUNNING);
484 remove_wait_queue(&vga_wait_queue, &wait);
485 rc = -ERESTARTSYS;
486 break;
487 }
488 schedule();
489 remove_wait_queue(&vga_wait_queue, &wait);
490 }
491 return rc;
492}
493EXPORT_SYMBOL(vga_get);
494
495/**
496 * vga_tryget - try to acquire & lock legacy VGA resources
497 * @pdev: PCI device of VGA card or NULL for system default
498 * @rsrc: bit mask of resources to acquire and lock
499 *
500 * Perform the same operation as vga_get(), but return an error (-EBUSY)
501 * instead of blocking if the resources are already locked by another card.
502 * Can be called in any context.
503 *
504 * On success, release the VGA resource again with vga_put().
505 *
506 * Returns:
507 *
508 * 0 on success, negative error code on failure.
509 */
510static int vga_tryget(struct pci_dev *pdev, unsigned int rsrc)
511{
512 struct vga_device *vgadev;
513 unsigned long flags;
514 int rc = 0;
515
516 vga_check_first_use();
517
518 /* The caller should check for this, but let's be sure */
519 if (pdev == NULL)
520 pdev = vga_default_device();
521 if (pdev == NULL)
522 return 0;
523 spin_lock_irqsave(&vga_lock, flags);
524 vgadev = vgadev_find(pdev);
525 if (vgadev == NULL) {
526 rc = -ENODEV;
527 goto bail;
528 }
529 if (__vga_tryget(vgadev, rsrc))
530 rc = -EBUSY;
531bail:
532 spin_unlock_irqrestore(&vga_lock, flags);
533 return rc;
534}
535
536/**
537 * vga_put - release lock on legacy VGA resources
538 * @pdev: PCI device of VGA card or NULL for system default
539 * @rsrc: bit mask of resource to release
540 *
541 * Release resources previously locked by vga_get() or vga_tryget(). The
542 * resources aren't disabled right away, so that a subsequent vga_get() on
543 * the same card will succeed immediately. Resources have a counter, so
544 * locks are only released if the counter reaches 0.
545 */
546void vga_put(struct pci_dev *pdev, unsigned int rsrc)
547{
548 struct vga_device *vgadev;
549 unsigned long flags;
550
551 /* The caller should check for this, but let's be sure */
552 if (pdev == NULL)
553 pdev = vga_default_device();
554 if (pdev == NULL)
555 return;
556 spin_lock_irqsave(&vga_lock, flags);
557 vgadev = vgadev_find(pdev);
558 if (vgadev == NULL)
559 goto bail;
560 __vga_put(vgadev, rsrc);
561bail:
562 spin_unlock_irqrestore(&vga_lock, flags);
563}
564EXPORT_SYMBOL(vga_put);
565
566static bool vga_is_firmware_default(struct pci_dev *pdev)
567{
568#if defined CONFIG_X86
569 return pdev == screen_info_pci_dev(&sysfb_primary_display.screen);
570#else
571 return false;
572#endif
573}
574
575static bool vga_arb_integrated_gpu(struct device *dev)
576{
577#if defined(CONFIG_ACPI)
578 return acpi_dev_is_video_device(ACPI_COMPANION(dev));
579#else
580 return false;
581#endif
582}
583
584/*
585 * Return true if vgadev is a better default VGA device than the best one
586 * we've seen so far.
587 */
588static bool vga_is_boot_device(struct vga_device *vgadev)
589{
590 struct vga_device *boot_vga = vgadev_find(vga_default_device());
591 struct pci_dev *pdev = vgadev->pdev;
592 u16 cmd, boot_cmd;
593
594 /*
595 * We select the default VGA device in this order:
596 * Firmware framebuffer (see vga_arb_select_default_device())
597 * Legacy VGA device (owns VGA_RSRC_LEGACY_MASK)
598 * Non-legacy integrated device (see vga_arb_select_default_device())
599 * Non-legacy discrete device (see vga_arb_select_default_device())
600 * Other device (see vga_arb_select_default_device())
601 */
602
603 /*
604 * We always prefer a firmware default device, so if we've already
605 * found one, there's no need to consider vgadev.
606 */
607 if (boot_vga && boot_vga->is_firmware_default)
608 return false;
609
610 if (vga_is_firmware_default(pdev)) {
611 vgadev->is_firmware_default = true;
612 return true;
613 }
614
615 /*
616 * A legacy VGA device has MEM and IO enabled and any bridges
617 * leading to it have PCI_BRIDGE_CTL_VGA enabled so the legacy
618 * resources ([mem 0xa0000-0xbffff], [io 0x3b0-0x3bb], etc) are
619 * routed to it.
620 *
621 * We use the first one we find, so if we've already found one,
622 * vgadev is no better.
623 */
624 if (boot_vga &&
625 (boot_vga->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)
626 return false;
627
628 if ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)
629 return true;
630
631 /*
632 * If we haven't found a legacy VGA device, accept a non-legacy
633 * device. It may have either IO or MEM enabled, and bridges may
634 * not have PCI_BRIDGE_CTL_VGA enabled, so it may not be able to
635 * use legacy VGA resources. Prefer an integrated GPU over others.
636 */
637 pci_read_config_word(pdev, PCI_COMMAND, &cmd);
638 if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) {
639
640 /*
641 * An integrated GPU overrides a previous non-legacy
642 * device. We expect only a single integrated GPU, but if
643 * there are more, we use the *last* because that was the
644 * previous behavior.
645 */
646 if (vga_arb_integrated_gpu(&pdev->dev))
647 return true;
648
649 /*
650 * We prefer the first non-legacy discrete device we find.
651 * If we already found one, vgadev is no better.
652 */
653 if (boot_vga) {
654 pci_read_config_word(boot_vga->pdev, PCI_COMMAND,
655 &boot_cmd);
656 if (boot_cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY))
657 return false;
658 }
659 return true;
660 }
661
662 return false;
663}
664
665/*
666 * Rules for using a bridge to control a VGA descendant decoding: if a bridge
667 * has only one VGA descendant then it can be used to control the VGA routing
668 * for that device. It should always use the bridge closest to the device to
669 * control it. If a bridge has a direct VGA descendant, but also have a sub-
670 * bridge VGA descendant then we cannot use that bridge to control the direct
671 * VGA descendant. So for every device we register, we need to iterate all
672 * its parent bridges so we can invalidate any devices using them properly.
673 */
674static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev)
675{
676 struct vga_device *same_bridge_vgadev;
677 struct pci_bus *new_bus, *bus;
678 struct pci_dev *new_bridge, *bridge;
679
680 vgadev->bridge_has_one_vga = true;
681
682 if (list_empty(&vga_list)) {
683 vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n");
684 return;
685 }
686
687 /* Iterate the new device's bridge hierarchy */
688 new_bus = vgadev->pdev->bus;
689 while (new_bus) {
690 new_bridge = new_bus->self;
691
692 /* Go through list of devices already registered */
693 list_for_each_entry(same_bridge_vgadev, &vga_list, list) {
694 bus = same_bridge_vgadev->pdev->bus;
695 bridge = bus->self;
696
697 /* See if it shares a bridge with this device */
698 if (new_bridge == bridge) {
699 /*
700 * If its direct parent bridge is the same
701 * as any bridge of this device then it can't
702 * be used for that device.
703 */
704 same_bridge_vgadev->bridge_has_one_vga = false;
705 }
706
707 /*
708 * Now iterate the previous device's bridge hierarchy.
709 * If the new device's parent bridge is in the other
710 * device's hierarchy, we can't use it to control this
711 * device.
712 */
713 while (bus) {
714 bridge = bus->self;
715
716 if (bridge && bridge == vgadev->pdev->bus->self)
717 vgadev->bridge_has_one_vga = false;
718
719 bus = bus->parent;
720 }
721 }
722 new_bus = new_bus->parent;
723 }
724
725 if (vgadev->bridge_has_one_vga)
726 vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n");
727 else
728 vgaarb_info(&vgadev->pdev->dev, "no bridge control possible\n");
729}
730
731/*
732 * Currently, we assume that the "initial" setup of the system is not sane,
733 * that is, we come up with conflicting devices and let the arbiter's
734 * client decide if devices decodes legacy things or not.
735 */
736static bool vga_arbiter_add_pci_device(struct pci_dev *pdev)
737{
738 struct vga_device *vgadev;
739 unsigned long flags;
740 struct pci_bus *bus;
741 struct pci_dev *bridge;
742 u16 cmd;
743
744 /* Allocate structure */
745 vgadev = kzalloc_obj(struct vga_device);
746 if (vgadev == NULL) {
747 vgaarb_err(&pdev->dev, "failed to allocate VGA arbiter data\n");
748 /*
749 * What to do on allocation failure? For now, let's just do
750 * nothing, I'm not sure there is anything saner to be done.
751 */
752 return false;
753 }
754
755 /* Take lock & check for duplicates */
756 spin_lock_irqsave(&vga_lock, flags);
757 if (vgadev_find(pdev) != NULL) {
758 BUG_ON(1);
759 goto fail;
760 }
761 vgadev->pdev = pdev;
762
763 /* By default, assume we decode everything */
764 vgadev->decodes = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM |
765 VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
766
767 /* By default, mark it as decoding */
768 vga_decode_count++;
769
770 /*
771 * Mark that we "own" resources based on our enables, we will
772 * clear that below if the bridge isn't forwarding.
773 */
774 pci_read_config_word(pdev, PCI_COMMAND, &cmd);
775 if (cmd & PCI_COMMAND_IO)
776 vgadev->owns |= VGA_RSRC_LEGACY_IO;
777 if (cmd & PCI_COMMAND_MEMORY)
778 vgadev->owns |= VGA_RSRC_LEGACY_MEM;
779
780 /* Check if VGA cycles can get down to us */
781 bus = pdev->bus;
782 while (bus) {
783 bridge = bus->self;
784 if (bridge) {
785 u16 l;
786
787 pci_read_config_word(bridge, PCI_BRIDGE_CONTROL, &l);
788 if (!(l & PCI_BRIDGE_CTL_VGA)) {
789 vgadev->owns = 0;
790 break;
791 }
792 }
793 bus = bus->parent;
794 }
795
796 if (vga_is_boot_device(vgadev)) {
797 vgaarb_info(&pdev->dev, "setting as boot VGA device%s\n",
798 vga_default_device() ?
799 " (overriding previous)" : "");
800 vga_set_default_device(pdev);
801 }
802
803 vga_arbiter_check_bridge_sharing(vgadev);
804
805 /* Add to the list */
806 list_add_tail(&vgadev->list, &vga_list);
807 vga_count++;
808 vgaarb_info(&pdev->dev, "VGA device added: decodes=%s,owns=%s,locks=%s\n",
809 vga_iostate_to_str(vgadev->decodes),
810 vga_iostate_to_str(vgadev->owns),
811 vga_iostate_to_str(vgadev->locks));
812
813 spin_unlock_irqrestore(&vga_lock, flags);
814 return true;
815fail:
816 spin_unlock_irqrestore(&vga_lock, flags);
817 kfree(vgadev);
818 return false;
819}
820
821static bool vga_arbiter_del_pci_device(struct pci_dev *pdev)
822{
823 struct vga_device *vgadev;
824 unsigned long flags;
825 bool ret = true;
826
827 spin_lock_irqsave(&vga_lock, flags);
828 vgadev = vgadev_find(pdev);
829 if (vgadev == NULL) {
830 ret = false;
831 goto bail;
832 }
833
834 if (vga_default == pdev)
835 vga_set_default_device(NULL);
836
837 if (vgadev->decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM))
838 vga_decode_count--;
839
840 /* Remove entry from list */
841 list_del(&vgadev->list);
842 vga_count--;
843
844 /* Wake up all possible waiters */
845 wake_up_all(&vga_wait_queue);
846bail:
847 spin_unlock_irqrestore(&vga_lock, flags);
848 kfree(vgadev);
849 return ret;
850}
851
852/* Called with the lock */
853static void vga_update_device_decodes(struct vga_device *vgadev,
854 unsigned int new_decodes)
855{
856 struct device *dev = &vgadev->pdev->dev;
857 unsigned int old_decodes = vgadev->decodes;
858 unsigned int decodes_removed = ~new_decodes & old_decodes;
859 unsigned int decodes_unlocked = vgadev->locks & decodes_removed;
860
861 vgadev->decodes = new_decodes;
862
863 vgaarb_info(dev, "VGA decodes changed: olddecodes=%s,decodes=%s:owns=%s\n",
864 vga_iostate_to_str(old_decodes),
865 vga_iostate_to_str(vgadev->decodes),
866 vga_iostate_to_str(vgadev->owns));
867
868 /* If we removed locked decodes, lock count goes to zero, and release */
869 if (decodes_unlocked) {
870 if (decodes_unlocked & VGA_RSRC_LEGACY_IO)
871 vgadev->io_lock_cnt = 0;
872 if (decodes_unlocked & VGA_RSRC_LEGACY_MEM)
873 vgadev->mem_lock_cnt = 0;
874 __vga_put(vgadev, decodes_unlocked);
875 }
876
877 /* Change decodes counter */
878 if (old_decodes & VGA_RSRC_LEGACY_MASK &&
879 !(new_decodes & VGA_RSRC_LEGACY_MASK))
880 vga_decode_count--;
881 if (!(old_decodes & VGA_RSRC_LEGACY_MASK) &&
882 new_decodes & VGA_RSRC_LEGACY_MASK)
883 vga_decode_count++;
884 vgaarb_dbg(dev, "decoding count now is: %d\n", vga_decode_count);
885}
886
887static void __vga_set_legacy_decoding(struct pci_dev *pdev,
888 unsigned int decodes,
889 bool userspace)
890{
891 struct vga_device *vgadev;
892 unsigned long flags;
893
894 decodes &= VGA_RSRC_LEGACY_MASK;
895
896 spin_lock_irqsave(&vga_lock, flags);
897 vgadev = vgadev_find(pdev);
898 if (vgadev == NULL)
899 goto bail;
900
901 /* Don't let userspace futz with kernel driver decodes */
902 if (userspace && vgadev->set_decode)
903 goto bail;
904
905 /* Update the device decodes + counter */
906 vga_update_device_decodes(vgadev, decodes);
907
908 /*
909 * XXX If somebody is going from "doesn't decode" to "decodes"
910 * state here, additional care must be taken as we may have pending
911 * ownership of non-legacy region.
912 */
913bail:
914 spin_unlock_irqrestore(&vga_lock, flags);
915}
916
917/**
918 * vga_set_legacy_decoding
919 * @pdev: PCI device of the VGA card
920 * @decodes: bit mask of what legacy regions the card decodes
921 *
922 * Indicate to the arbiter if the card decodes legacy VGA IOs, legacy VGA
923 * Memory, both, or none. All cards default to both, the card driver (fbdev for
924 * example) should tell the arbiter if it has disabled legacy decoding, so the
925 * card can be left out of the arbitration process (and can be safe to take
926 * interrupts at any time.
927 */
928void vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes)
929{
930 __vga_set_legacy_decoding(pdev, decodes, false);
931}
932EXPORT_SYMBOL(vga_set_legacy_decoding);
933
934/**
935 * vga_client_register - register or unregister a VGA arbitration client
936 * @pdev: PCI device of the VGA client
937 * @set_decode: VGA decode change callback
938 *
939 * Clients have two callback mechanisms they can use.
940 *
941 * @set_decode callback: If a client can disable its GPU VGA resource, it
942 * will get a callback from this to set the encode/decode state.
943 *
944 * Rationale: we cannot disable VGA decode resources unconditionally
945 * because some single GPU laptops seem to require ACPI or BIOS access to
946 * the VGA registers to control things like backlights etc. Hopefully newer
947 * multi-GPU laptops do something saner, and desktops won't have any
948 * special ACPI for this. The driver will get a callback when VGA
949 * arbitration is first used by userspace since some older X servers have
950 * issues.
951 *
952 * Does not check whether a client for @pdev has been registered already.
953 *
954 * To unregister, call vga_client_unregister().
955 *
956 * Returns: 0 on success, -ENODEV on failure
957 */
958int vga_client_register(struct pci_dev *pdev,
959 unsigned int (*set_decode)(struct pci_dev *pdev, bool decode))
960{
961 unsigned long flags;
962 struct vga_device *vgadev;
963
964 spin_lock_irqsave(&vga_lock, flags);
965 vgadev = vgadev_find(pdev);
966 if (vgadev)
967 vgadev->set_decode = set_decode;
968 spin_unlock_irqrestore(&vga_lock, flags);
969 if (!vgadev)
970 return -ENODEV;
971 return 0;
972}
973EXPORT_SYMBOL(vga_client_register);
974
975/*
976 * Char driver implementation
977 *
978 * Semantics is:
979 *
980 * open : Open user instance of the arbiter. By default, it's
981 * attached to the default VGA device of the system.
982 *
983 * close : Close user instance, release locks
984 *
985 * read : Return a string indicating the status of the target.
986 * An IO state string is of the form {io,mem,io+mem,none},
987 * mc and ic are respectively mem and io lock counts (for
988 * debugging/diagnostic only). "decodes" indicate what the
989 * card currently decodes, "owns" indicates what is currently
990 * enabled on it, and "locks" indicates what is locked by this
991 * card. If the card is unplugged, we get "invalid" then for
992 * card_ID and an -ENODEV error is returned for any command
993 * until a new card is targeted
994 *
995 * "<card_ID>,decodes=<io_state>,owns=<io_state>,locks=<io_state> (ic,mc)"
996 *
997 * write : write a command to the arbiter. List of commands is:
998 *
999 * target <card_ID> : switch target to card <card_ID> (see below)
1000 * lock <io_state> : acquire locks on target ("none" is invalid io_state)
1001 * trylock <io_state> : non-blocking acquire locks on target
1002 * unlock <io_state> : release locks on target
1003 * unlock all : release all locks on target held by this user
1004 * decodes <io_state> : set the legacy decoding attributes for the card
1005 *
1006 * poll : event if something change on any card (not just the target)
1007 *
1008 * card_ID is of the form "PCI:domain:bus:dev.fn". It can be set to "default"
1009 * to go back to the system default card (TODO: not implemented yet).
1010 * Currently, only PCI is supported as a prefix, but the userland API may
1011 * support other bus types in the future, even if the current kernel
1012 * implementation doesn't.
1013 *
1014 * Note about locks:
1015 *
1016 * The driver keeps track of which user has what locks on which card. It
1017 * supports stacking, like the kernel one. This complicates the implementation
1018 * a bit, but makes the arbiter more tolerant to userspace problems and able
1019 * to properly cleanup in all cases when a process dies.
1020 * Currently, a max of 16 cards simultaneously can have locks issued from
1021 * userspace for a given user (file descriptor instance) of the arbiter.
1022 *
1023 * If the device is hot-unplugged, there is a hook inside the module to notify
1024 * it being added/removed in the system and automatically added/removed in
1025 * the arbiter.
1026 */
1027
1028#define MAX_USER_CARDS CONFIG_VGA_ARB_MAX_GPUS
1029#define PCI_INVALID_CARD ((struct pci_dev *)-1UL)
1030
1031/* Each user has an array of these, tracking which cards have locks */
1032struct vga_arb_user_card {
1033 struct pci_dev *pdev;
1034 unsigned int mem_cnt;
1035 unsigned int io_cnt;
1036};
1037
1038struct vga_arb_private {
1039 struct list_head list;
1040 struct pci_dev *target;
1041 struct vga_arb_user_card cards[MAX_USER_CARDS];
1042 spinlock_t lock;
1043};
1044
1045static LIST_HEAD(vga_user_list);
1046static DEFINE_SPINLOCK(vga_user_lock);
1047
1048
1049/*
1050 * Take a string in the format: "PCI:domain:bus:dev.fn" and return the
1051 * respective values. If the string is not in this format, return 0.
1052 */
1053static int vga_pci_str_to_vars(char *buf, int count, unsigned int *domain,
1054 unsigned int *bus, unsigned int *devfn)
1055{
1056 int n;
1057 unsigned int slot, func;
1058
1059 n = sscanf(buf, "PCI:%x:%x:%x.%x", domain, bus, &slot, &func);
1060 if (n != 4)
1061 return 0;
1062
1063 *devfn = PCI_DEVFN(slot, func);
1064
1065 return 1;
1066}
1067
1068static ssize_t vga_arb_read(struct file *file, char __user *buf,
1069 size_t count, loff_t *ppos)
1070{
1071 struct vga_arb_private *priv = file->private_data;
1072 struct vga_device *vgadev;
1073 struct pci_dev *pdev;
1074 unsigned long flags;
1075 size_t len;
1076 int rc;
1077 char *lbuf;
1078
1079 lbuf = kmalloc(1024, GFP_KERNEL);
1080 if (lbuf == NULL)
1081 return -ENOMEM;
1082
1083 /* Protect vga_list */
1084 spin_lock_irqsave(&vga_lock, flags);
1085
1086 /* If we are targeting the default, use it */
1087 pdev = priv->target;
1088 if (pdev == NULL || pdev == PCI_INVALID_CARD) {
1089 spin_unlock_irqrestore(&vga_lock, flags);
1090 len = sprintf(lbuf, "invalid");
1091 goto done;
1092 }
1093
1094 /* Find card vgadev structure */
1095 vgadev = vgadev_find(pdev);
1096 if (vgadev == NULL) {
1097 /*
1098 * Wow, it's not in the list, that shouldn't happen, let's
1099 * fix us up and return invalid card.
1100 */
1101 spin_unlock_irqrestore(&vga_lock, flags);
1102 len = sprintf(lbuf, "invalid");
1103 goto done;
1104 }
1105
1106 /* Fill the buffer with info */
1107 len = snprintf(lbuf, 1024,
1108 "count:%d,PCI:%s,decodes=%s,owns=%s,locks=%s(%u:%u)\n",
1109 vga_decode_count, pci_name(pdev),
1110 vga_iostate_to_str(vgadev->decodes),
1111 vga_iostate_to_str(vgadev->owns),
1112 vga_iostate_to_str(vgadev->locks),
1113 vgadev->io_lock_cnt, vgadev->mem_lock_cnt);
1114
1115 spin_unlock_irqrestore(&vga_lock, flags);
1116done:
1117
1118 /* Copy that to user */
1119 if (len > count)
1120 len = count;
1121 rc = copy_to_user(buf, lbuf, len);
1122 kfree(lbuf);
1123 if (rc)
1124 return -EFAULT;
1125 return len;
1126}
1127
1128/*
1129 * TODO: To avoid parsing inside kernel and to improve the speed we may
1130 * consider use ioctl here
1131 */
1132static ssize_t vga_arb_write(struct file *file, const char __user *buf,
1133 size_t count, loff_t *ppos)
1134{
1135 struct vga_arb_private *priv = file->private_data;
1136 struct vga_arb_user_card *uc = NULL;
1137 struct pci_dev *pdev;
1138
1139 unsigned int io_state;
1140
1141 char kbuf[64], *curr_pos;
1142 size_t remaining = count;
1143
1144 int err;
1145 int ret_val;
1146 int i;
1147
1148 if (count >= sizeof(kbuf))
1149 return -EINVAL;
1150 if (copy_from_user(kbuf, buf, count))
1151 return -EFAULT;
1152 curr_pos = kbuf;
1153 kbuf[count] = '\0';
1154
1155 if (strncmp(curr_pos, "lock ", 5) == 0) {
1156 curr_pos += 5;
1157 remaining -= 5;
1158
1159 pr_debug("client 0x%p called 'lock'\n", priv);
1160
1161 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) {
1162 ret_val = -EPROTO;
1163 goto done;
1164 }
1165 if (io_state == VGA_RSRC_NONE) {
1166 ret_val = -EPROTO;
1167 goto done;
1168 }
1169
1170 pdev = priv->target;
1171 if (priv->target == NULL) {
1172 ret_val = -ENODEV;
1173 goto done;
1174 }
1175
1176 err = vga_get_uninterruptible(pdev, io_state);
1177 if (err) {
1178 ret_val = err;
1179 goto done;
1180 }
1181
1182 /* Update the client's locks lists */
1183 for (i = 0; i < MAX_USER_CARDS; i++) {
1184 if (priv->cards[i].pdev == pdev) {
1185 if (io_state & VGA_RSRC_LEGACY_IO)
1186 priv->cards[i].io_cnt++;
1187 if (io_state & VGA_RSRC_LEGACY_MEM)
1188 priv->cards[i].mem_cnt++;
1189 break;
1190 }
1191 }
1192
1193 ret_val = count;
1194 goto done;
1195 } else if (strncmp(curr_pos, "unlock ", 7) == 0) {
1196 curr_pos += 7;
1197 remaining -= 7;
1198
1199 pr_debug("client 0x%p called 'unlock'\n", priv);
1200
1201 if (strncmp(curr_pos, "all", 3) == 0)
1202 io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM;
1203 else {
1204 if (!vga_str_to_iostate
1205 (curr_pos, remaining, &io_state)) {
1206 ret_val = -EPROTO;
1207 goto done;
1208 }
1209 /* TODO: Add this?
1210 if (io_state == VGA_RSRC_NONE) {
1211 ret_val = -EPROTO;
1212 goto done;
1213 }
1214 */
1215 }
1216
1217 pdev = priv->target;
1218 if (priv->target == NULL) {
1219 ret_val = -ENODEV;
1220 goto done;
1221 }
1222 for (i = 0; i < MAX_USER_CARDS; i++) {
1223 if (priv->cards[i].pdev == pdev)
1224 uc = &priv->cards[i];
1225 }
1226
1227 if (!uc) {
1228 ret_val = -EINVAL;
1229 goto done;
1230 }
1231
1232 if (io_state & VGA_RSRC_LEGACY_IO && uc->io_cnt == 0) {
1233 ret_val = -EINVAL;
1234 goto done;
1235 }
1236
1237 if (io_state & VGA_RSRC_LEGACY_MEM && uc->mem_cnt == 0) {
1238 ret_val = -EINVAL;
1239 goto done;
1240 }
1241
1242 vga_put(pdev, io_state);
1243
1244 if (io_state & VGA_RSRC_LEGACY_IO)
1245 uc->io_cnt--;
1246 if (io_state & VGA_RSRC_LEGACY_MEM)
1247 uc->mem_cnt--;
1248
1249 ret_val = count;
1250 goto done;
1251 } else if (strncmp(curr_pos, "trylock ", 8) == 0) {
1252 curr_pos += 8;
1253 remaining -= 8;
1254
1255 pr_debug("client 0x%p called 'trylock'\n", priv);
1256
1257 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) {
1258 ret_val = -EPROTO;
1259 goto done;
1260 }
1261 /* TODO: Add this?
1262 if (io_state == VGA_RSRC_NONE) {
1263 ret_val = -EPROTO;
1264 goto done;
1265 }
1266 */
1267
1268 pdev = priv->target;
1269 if (priv->target == NULL) {
1270 ret_val = -ENODEV;
1271 goto done;
1272 }
1273
1274 if (vga_tryget(pdev, io_state)) {
1275 /* Update the client's locks lists... */
1276 for (i = 0; i < MAX_USER_CARDS; i++) {
1277 if (priv->cards[i].pdev == pdev) {
1278 if (io_state & VGA_RSRC_LEGACY_IO)
1279 priv->cards[i].io_cnt++;
1280 if (io_state & VGA_RSRC_LEGACY_MEM)
1281 priv->cards[i].mem_cnt++;
1282 break;
1283 }
1284 }
1285 ret_val = count;
1286 goto done;
1287 } else {
1288 ret_val = -EBUSY;
1289 goto done;
1290 }
1291
1292 } else if (strncmp(curr_pos, "target ", 7) == 0) {
1293 unsigned int domain, bus, devfn;
1294 struct vga_device *vgadev;
1295
1296 curr_pos += 7;
1297 remaining -= 7;
1298 pr_debug("client 0x%p called 'target'\n", priv);
1299 /* If target is default */
1300 if (!strncmp(curr_pos, "default", 7))
1301 pdev = pci_dev_get(vga_default_device());
1302 else {
1303 if (!vga_pci_str_to_vars(curr_pos, remaining,
1304 &domain, &bus, &devfn)) {
1305 ret_val = -EPROTO;
1306 goto done;
1307 }
1308 pdev = pci_get_domain_bus_and_slot(domain, bus, devfn);
1309 if (!pdev) {
1310 pr_debug("invalid PCI address %04x:%02x:%02x.%x\n",
1311 domain, bus, PCI_SLOT(devfn),
1312 PCI_FUNC(devfn));
1313 ret_val = -ENODEV;
1314 goto done;
1315 }
1316
1317 pr_debug("%s ==> %04x:%02x:%02x.%x pdev %p\n", curr_pos,
1318 domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn),
1319 pdev);
1320 }
1321
1322 vgadev = vgadev_find(pdev);
1323 pr_debug("vgadev %p\n", vgadev);
1324 if (vgadev == NULL) {
1325 if (pdev) {
1326 vgaarb_dbg(&pdev->dev, "not a VGA device\n");
1327 pci_dev_put(pdev);
1328 }
1329
1330 ret_val = -ENODEV;
1331 goto done;
1332 }
1333
1334 priv->target = pdev;
1335 for (i = 0; i < MAX_USER_CARDS; i++) {
1336 if (priv->cards[i].pdev == pdev)
1337 break;
1338 if (priv->cards[i].pdev == NULL) {
1339 priv->cards[i].pdev = pdev;
1340 priv->cards[i].io_cnt = 0;
1341 priv->cards[i].mem_cnt = 0;
1342 break;
1343 }
1344 }
1345 if (i == MAX_USER_CARDS) {
1346 vgaarb_dbg(&pdev->dev, "maximum user cards (%d) number reached, ignoring this one!\n",
1347 MAX_USER_CARDS);
1348 pci_dev_put(pdev);
1349 /* XXX: Which value to return? */
1350 ret_val = -ENOMEM;
1351 goto done;
1352 }
1353
1354 ret_val = count;
1355 pci_dev_put(pdev);
1356 goto done;
1357
1358
1359 } else if (strncmp(curr_pos, "decodes ", 8) == 0) {
1360 curr_pos += 8;
1361 remaining -= 8;
1362 pr_debug("client 0x%p called 'decodes'\n", priv);
1363
1364 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) {
1365 ret_val = -EPROTO;
1366 goto done;
1367 }
1368 pdev = priv->target;
1369 if (priv->target == NULL) {
1370 ret_val = -ENODEV;
1371 goto done;
1372 }
1373
1374 __vga_set_legacy_decoding(pdev, io_state, true);
1375 ret_val = count;
1376 goto done;
1377 }
1378 /* If we got here, the message written is not part of the protocol! */
1379 return -EPROTO;
1380
1381done:
1382 return ret_val;
1383}
1384
1385static __poll_t vga_arb_fpoll(struct file *file, poll_table *wait)
1386{
1387 pr_debug("%s\n", __func__);
1388
1389 poll_wait(file, &vga_wait_queue, wait);
1390 return EPOLLIN;
1391}
1392
1393static int vga_arb_open(struct inode *inode, struct file *file)
1394{
1395 struct vga_arb_private *priv;
1396 unsigned long flags;
1397
1398 pr_debug("%s\n", __func__);
1399
1400 priv = kzalloc_obj(*priv);
1401 if (priv == NULL)
1402 return -ENOMEM;
1403 spin_lock_init(&priv->lock);
1404 file->private_data = priv;
1405
1406 spin_lock_irqsave(&vga_user_lock, flags);
1407 list_add(&priv->list, &vga_user_list);
1408 spin_unlock_irqrestore(&vga_user_lock, flags);
1409
1410 /* Set the client's lists of locks */
1411 priv->target = vga_default_device(); /* Maybe this is still null! */
1412 priv->cards[0].pdev = priv->target;
1413 priv->cards[0].io_cnt = 0;
1414 priv->cards[0].mem_cnt = 0;
1415
1416 return 0;
1417}
1418
1419static int vga_arb_release(struct inode *inode, struct file *file)
1420{
1421 struct vga_arb_private *priv = file->private_data;
1422 struct vga_arb_user_card *uc;
1423 unsigned long flags;
1424 int i;
1425
1426 pr_debug("%s\n", __func__);
1427
1428 spin_lock_irqsave(&vga_user_lock, flags);
1429 list_del(&priv->list);
1430 for (i = 0; i < MAX_USER_CARDS; i++) {
1431 uc = &priv->cards[i];
1432 if (uc->pdev == NULL)
1433 continue;
1434 vgaarb_dbg(&uc->pdev->dev, "uc->io_cnt == %d, uc->mem_cnt == %d\n",
1435 uc->io_cnt, uc->mem_cnt);
1436 while (uc->io_cnt--)
1437 vga_put(uc->pdev, VGA_RSRC_LEGACY_IO);
1438 while (uc->mem_cnt--)
1439 vga_put(uc->pdev, VGA_RSRC_LEGACY_MEM);
1440 }
1441 spin_unlock_irqrestore(&vga_user_lock, flags);
1442
1443 kfree(priv);
1444
1445 return 0;
1446}
1447
1448/*
1449 * Callback any registered clients to let them know we have a change in VGA
1450 * cards.
1451 */
1452static void vga_arbiter_notify_clients(void)
1453{
1454 struct vga_device *vgadev;
1455 unsigned long flags;
1456 unsigned int new_decodes;
1457 bool new_state;
1458
1459 if (!vga_arbiter_used)
1460 return;
1461
1462 new_state = (vga_count > 1) ? false : true;
1463
1464 spin_lock_irqsave(&vga_lock, flags);
1465 list_for_each_entry(vgadev, &vga_list, list) {
1466 if (vgadev->set_decode) {
1467 new_decodes = vgadev->set_decode(vgadev->pdev,
1468 new_state);
1469 vga_update_device_decodes(vgadev, new_decodes);
1470 }
1471 }
1472 spin_unlock_irqrestore(&vga_lock, flags);
1473}
1474
1475static int pci_notify(struct notifier_block *nb, unsigned long action,
1476 void *data)
1477{
1478 struct device *dev = data;
1479 struct pci_dev *pdev = to_pci_dev(dev);
1480 bool notify = false;
1481
1482 vgaarb_dbg(dev, "%s\n", __func__);
1483
1484 /* Only deal with VGA class devices */
1485 if (!pci_is_vga(pdev))
1486 return 0;
1487
1488 /*
1489 * For now, we're only interested in devices added and removed.
1490 * I didn't test this thing here, so someone needs to double check
1491 * for the cases of hot-pluggable VGA cards.
1492 */
1493 if (action == BUS_NOTIFY_ADD_DEVICE)
1494 notify = vga_arbiter_add_pci_device(pdev);
1495 else if (action == BUS_NOTIFY_DEL_DEVICE)
1496 notify = vga_arbiter_del_pci_device(pdev);
1497
1498 if (notify)
1499 vga_arbiter_notify_clients();
1500 return 0;
1501}
1502
1503static struct notifier_block pci_notifier = {
1504 .notifier_call = pci_notify,
1505};
1506
1507static const struct file_operations vga_arb_device_fops = {
1508 .read = vga_arb_read,
1509 .write = vga_arb_write,
1510 .poll = vga_arb_fpoll,
1511 .open = vga_arb_open,
1512 .release = vga_arb_release,
1513 .llseek = noop_llseek,
1514};
1515
1516static struct miscdevice vga_arb_device = {
1517 MISC_DYNAMIC_MINOR, "vga_arbiter", &vga_arb_device_fops
1518};
1519
1520static int __init vga_arb_device_init(void)
1521{
1522 int rc;
1523 struct pci_dev *pdev;
1524
1525 rc = misc_register(&vga_arb_device);
1526 if (rc < 0)
1527 pr_err("error %d registering device\n", rc);
1528
1529 bus_register_notifier(&pci_bus_type, &pci_notifier);
1530
1531 /* Add all VGA class PCI devices by default */
1532 pdev = NULL;
1533 while ((pdev =
1534 pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
1535 PCI_ANY_ID, pdev)) != NULL) {
1536 if (pci_is_vga(pdev))
1537 vga_arbiter_add_pci_device(pdev);
1538 }
1539
1540 pr_info("loaded\n");
1541 return rc;
1542}
1543subsys_initcall_sync(vga_arb_device_init);