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 <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 | |
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/screen_info.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 | |
36 | static 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 | */ |
42 | struct 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 | |
57 | static LIST_HEAD(vga_list); |
58 | static int vga_count, vga_decode_count; |
59 | static bool vga_arbiter_used; |
60 | static DEFINE_SPINLOCK(vga_lock); |
61 | static DECLARE_WAIT_QUEUE_HEAD(vga_wait_queue); |
62 | |
63 | static 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 | |
78 | static 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; |
97 | both: |
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 */ |
103 | static struct pci_dev *vga_default; |
104 | |
105 | /* Find somebody in our list */ |
106 | static 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 | */ |
132 | struct pci_dev *vga_default_device(void) |
133 | { |
134 | return vga_default; |
135 | } |
136 | EXPORT_SYMBOL_GPL(vga_default_device); |
137 | |
138 | void vga_set_default_device(struct pci_dev *pdev) |
139 | { |
140 | if (vga_default == pdev) |
141 | return; |
142 | |
143 | pci_dev_put(dev: vga_default); |
144 | vga_default = pci_dev_get(dev: 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) |
157 | int vga_remove_vgacon(struct pci_dev *pdev) |
158 | { |
159 | return 0; |
160 | } |
161 | #elif !defined(CONFIG_DUMMY_CONSOLE) |
162 | int vga_remove_vgacon(struct pci_dev *pdev) |
163 | { |
164 | return -ENODEV; |
165 | } |
166 | #else |
167 | int 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(csw: &vga_con)) |
177 | ret = do_take_over_console(sw: &dummy_con, first: 0, |
178 | MAX_NR_CONSOLES - 1, deflt: 1); |
179 | if (ret == 0) { |
180 | ret = do_unregister_con_driver(csw: &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 |
191 | EXPORT_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 | */ |
198 | static 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 | |
210 | static 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 | |
219 | /* |
220 | * Account for "normal" resources to lock. If we decode the legacy, |
221 | * counterpart, we need to request it as well |
222 | */ |
223 | if ((rsrc & VGA_RSRC_NORMAL_IO) && |
224 | (vgadev->decodes & VGA_RSRC_LEGACY_IO)) |
225 | rsrc |= VGA_RSRC_LEGACY_IO; |
226 | if ((rsrc & VGA_RSRC_NORMAL_MEM) && |
227 | (vgadev->decodes & VGA_RSRC_LEGACY_MEM)) |
228 | rsrc |= VGA_RSRC_LEGACY_MEM; |
229 | |
230 | vgaarb_dbg(dev, "%s: %d\n" , __func__, rsrc); |
231 | vgaarb_dbg(dev, "%s: owns: %d\n" , __func__, vgadev->owns); |
232 | |
233 | /* Check what resources we need to acquire */ |
234 | wants = rsrc & ~vgadev->owns; |
235 | |
236 | /* We already own everything, just mark locked & bye bye */ |
237 | if (wants == 0) |
238 | goto lock_them; |
239 | |
240 | /* |
241 | * We don't need to request a legacy resource, we just enable |
242 | * appropriate decoding and go. |
243 | */ |
244 | legacy_wants = wants & VGA_RSRC_LEGACY_MASK; |
245 | if (legacy_wants == 0) |
246 | goto enable_them; |
247 | |
248 | /* Ok, we don't, let's find out who we need to kick off */ |
249 | list_for_each_entry(conflict, &vga_list, list) { |
250 | unsigned int lwants = legacy_wants; |
251 | unsigned int change_bridge = 0; |
252 | |
253 | /* Don't conflict with myself */ |
254 | if (vgadev == conflict) |
255 | continue; |
256 | |
257 | /* |
258 | * We have a possible conflict. Before we go further, we must |
259 | * check if we sit on the same bus as the conflicting device. |
260 | * If we don't, then we must tie both IO and MEM resources |
261 | * together since there is only a single bit controlling |
262 | * VGA forwarding on P2P bridges. |
263 | */ |
264 | if (vgadev->pdev->bus != conflict->pdev->bus) { |
265 | change_bridge = 1; |
266 | lwants = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; |
267 | } |
268 | |
269 | /* |
270 | * Check if the guy has a lock on the resource. If he does, |
271 | * return the conflicting entry. |
272 | */ |
273 | if (conflict->locks & lwants) |
274 | return conflict; |
275 | |
276 | /* |
277 | * Ok, now check if it owns the resource we want. We can |
278 | * lock resources that are not decoded; therefore a device |
279 | * can own resources it doesn't decode. |
280 | */ |
281 | match = lwants & conflict->owns; |
282 | if (!match) |
283 | continue; |
284 | |
285 | /* |
286 | * Looks like he doesn't have a lock, we can steal them |
287 | * from him. |
288 | */ |
289 | |
290 | flags = 0; |
291 | pci_bits = 0; |
292 | |
293 | /* |
294 | * If we can't control legacy resources via the bridge, we |
295 | * also need to disable normal decoding. |
296 | */ |
297 | if (!conflict->bridge_has_one_vga) { |
298 | if ((match & conflict->decodes) & VGA_RSRC_LEGACY_MEM) |
299 | pci_bits |= PCI_COMMAND_MEMORY; |
300 | if ((match & conflict->decodes) & VGA_RSRC_LEGACY_IO) |
301 | pci_bits |= PCI_COMMAND_IO; |
302 | |
303 | if (pci_bits) |
304 | flags |= PCI_VGA_STATE_CHANGE_DECODES; |
305 | } |
306 | |
307 | if (change_bridge) |
308 | flags |= PCI_VGA_STATE_CHANGE_BRIDGE; |
309 | |
310 | pci_set_vga_state(pdev: conflict->pdev, decode: false, command_bits: pci_bits, flags); |
311 | conflict->owns &= ~match; |
312 | |
313 | /* If we disabled normal decoding, reflect it in owns */ |
314 | if (pci_bits & PCI_COMMAND_MEMORY) |
315 | conflict->owns &= ~VGA_RSRC_NORMAL_MEM; |
316 | if (pci_bits & PCI_COMMAND_IO) |
317 | conflict->owns &= ~VGA_RSRC_NORMAL_IO; |
318 | } |
319 | |
320 | enable_them: |
321 | /* |
322 | * Ok, we got it, everybody conflicting has been disabled, let's |
323 | * enable us. Mark any bits in "owns" regardless of whether we |
324 | * decoded them. We can lock resources we don't decode, therefore |
325 | * we must track them via "owns". |
326 | */ |
327 | flags = 0; |
328 | pci_bits = 0; |
329 | |
330 | if (!vgadev->bridge_has_one_vga) { |
331 | flags |= PCI_VGA_STATE_CHANGE_DECODES; |
332 | if (wants & (VGA_RSRC_LEGACY_MEM|VGA_RSRC_NORMAL_MEM)) |
333 | pci_bits |= PCI_COMMAND_MEMORY; |
334 | if (wants & (VGA_RSRC_LEGACY_IO|VGA_RSRC_NORMAL_IO)) |
335 | pci_bits |= PCI_COMMAND_IO; |
336 | } |
337 | if (wants & VGA_RSRC_LEGACY_MASK) |
338 | flags |= PCI_VGA_STATE_CHANGE_BRIDGE; |
339 | |
340 | pci_set_vga_state(pdev: vgadev->pdev, decode: true, command_bits: pci_bits, flags); |
341 | |
342 | vgadev->owns |= wants; |
343 | lock_them: |
344 | vgadev->locks |= (rsrc & VGA_RSRC_LEGACY_MASK); |
345 | if (rsrc & VGA_RSRC_LEGACY_IO) |
346 | vgadev->io_lock_cnt++; |
347 | if (rsrc & VGA_RSRC_LEGACY_MEM) |
348 | vgadev->mem_lock_cnt++; |
349 | if (rsrc & VGA_RSRC_NORMAL_IO) |
350 | vgadev->io_norm_cnt++; |
351 | if (rsrc & VGA_RSRC_NORMAL_MEM) |
352 | vgadev->mem_norm_cnt++; |
353 | |
354 | return NULL; |
355 | } |
356 | |
357 | static void __vga_put(struct vga_device *vgadev, unsigned int rsrc) |
358 | { |
359 | struct device *dev = &vgadev->pdev->dev; |
360 | unsigned int old_locks = vgadev->locks; |
361 | |
362 | vgaarb_dbg(dev, "%s\n" , __func__); |
363 | |
364 | /* |
365 | * Update our counters and account for equivalent legacy resources |
366 | * if we decode them. |
367 | */ |
368 | if ((rsrc & VGA_RSRC_NORMAL_IO) && vgadev->io_norm_cnt > 0) { |
369 | vgadev->io_norm_cnt--; |
370 | if (vgadev->decodes & VGA_RSRC_LEGACY_IO) |
371 | rsrc |= VGA_RSRC_LEGACY_IO; |
372 | } |
373 | if ((rsrc & VGA_RSRC_NORMAL_MEM) && vgadev->mem_norm_cnt > 0) { |
374 | vgadev->mem_norm_cnt--; |
375 | if (vgadev->decodes & VGA_RSRC_LEGACY_MEM) |
376 | rsrc |= VGA_RSRC_LEGACY_MEM; |
377 | } |
378 | if ((rsrc & VGA_RSRC_LEGACY_IO) && vgadev->io_lock_cnt > 0) |
379 | vgadev->io_lock_cnt--; |
380 | if ((rsrc & VGA_RSRC_LEGACY_MEM) && vgadev->mem_lock_cnt > 0) |
381 | vgadev->mem_lock_cnt--; |
382 | |
383 | /* |
384 | * Just clear lock bits, we do lazy operations so we don't really |
385 | * have to bother about anything else at this point. |
386 | */ |
387 | if (vgadev->io_lock_cnt == 0) |
388 | vgadev->locks &= ~VGA_RSRC_LEGACY_IO; |
389 | if (vgadev->mem_lock_cnt == 0) |
390 | vgadev->locks &= ~VGA_RSRC_LEGACY_MEM; |
391 | |
392 | /* |
393 | * Kick the wait queue in case somebody was waiting if we actually |
394 | * released something. |
395 | */ |
396 | if (old_locks != vgadev->locks) |
397 | wake_up_all(&vga_wait_queue); |
398 | } |
399 | |
400 | /** |
401 | * vga_get - acquire & lock VGA resources |
402 | * @pdev: PCI device of the VGA card or NULL for the system default |
403 | * @rsrc: bit mask of resources to acquire and lock |
404 | * @interruptible: blocking should be interruptible by signals ? |
405 | * |
406 | * Acquire VGA resources for the given card and mark those resources |
407 | * locked. If the resources requested are "normal" (and not legacy) |
408 | * resources, the arbiter will first check whether the card is doing legacy |
409 | * decoding for that type of resource. If yes, the lock is "converted" into |
410 | * a legacy resource lock. |
411 | * |
412 | * The arbiter will first look for all VGA cards that might conflict and disable |
413 | * their IOs and/or Memory access, including VGA forwarding on P2P bridges if |
414 | * necessary, so that the requested resources can be used. Then, the card is |
415 | * marked as locking these resources and the IO and/or Memory accesses are |
416 | * enabled on the card (including VGA forwarding on parent P2P bridges if any). |
417 | * |
418 | * This function will block if some conflicting card is already locking one of |
419 | * the required resources (or any resource on a different bus segment, since P2P |
420 | * bridges don't differentiate VGA memory and IO afaik). You can indicate |
421 | * whether this blocking should be interruptible by a signal (for userland |
422 | * interface) or not. |
423 | * |
424 | * Must not be called at interrupt time or in atomic context. If the card |
425 | * already owns the resources, the function succeeds. Nested calls are |
426 | * supported (a per-resource counter is maintained) |
427 | * |
428 | * On success, release the VGA resource again with vga_put(). |
429 | * |
430 | * Returns: |
431 | * |
432 | * 0 on success, negative error code on failure. |
433 | */ |
434 | int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible) |
435 | { |
436 | struct vga_device *vgadev, *conflict; |
437 | unsigned long flags; |
438 | wait_queue_entry_t wait; |
439 | int rc = 0; |
440 | |
441 | vga_check_first_use(); |
442 | /* The caller should check for this, but let's be sure */ |
443 | if (pdev == NULL) |
444 | pdev = vga_default_device(); |
445 | if (pdev == NULL) |
446 | return 0; |
447 | |
448 | for (;;) { |
449 | spin_lock_irqsave(&vga_lock, flags); |
450 | vgadev = vgadev_find(pdev); |
451 | if (vgadev == NULL) { |
452 | spin_unlock_irqrestore(lock: &vga_lock, flags); |
453 | rc = -ENODEV; |
454 | break; |
455 | } |
456 | conflict = __vga_tryget(vgadev, rsrc); |
457 | spin_unlock_irqrestore(lock: &vga_lock, flags); |
458 | if (conflict == NULL) |
459 | break; |
460 | |
461 | /* |
462 | * We have a conflict; we wait until somebody kicks the |
463 | * work queue. Currently we have one work queue that we |
464 | * kick each time some resources are released, but it would |
465 | * be fairly easy to have a per-device one so that we only |
466 | * need to attach to the conflicting device. |
467 | */ |
468 | init_waitqueue_entry(wq_entry: &wait, current); |
469 | add_wait_queue(wq_head: &vga_wait_queue, wq_entry: &wait); |
470 | set_current_state(interruptible ? |
471 | TASK_INTERRUPTIBLE : |
472 | TASK_UNINTERRUPTIBLE); |
473 | if (interruptible && signal_pending(current)) { |
474 | __set_current_state(TASK_RUNNING); |
475 | remove_wait_queue(wq_head: &vga_wait_queue, wq_entry: &wait); |
476 | rc = -ERESTARTSYS; |
477 | break; |
478 | } |
479 | schedule(); |
480 | remove_wait_queue(wq_head: &vga_wait_queue, wq_entry: &wait); |
481 | } |
482 | return rc; |
483 | } |
484 | EXPORT_SYMBOL(vga_get); |
485 | |
486 | /** |
487 | * vga_tryget - try to acquire & lock legacy VGA resources |
488 | * @pdev: PCI device of VGA card or NULL for system default |
489 | * @rsrc: bit mask of resources to acquire and lock |
490 | * |
491 | * Perform the same operation as vga_get(), but return an error (-EBUSY) |
492 | * instead of blocking if the resources are already locked by another card. |
493 | * Can be called in any context. |
494 | * |
495 | * On success, release the VGA resource again with vga_put(). |
496 | * |
497 | * Returns: |
498 | * |
499 | * 0 on success, negative error code on failure. |
500 | */ |
501 | static int vga_tryget(struct pci_dev *pdev, unsigned int rsrc) |
502 | { |
503 | struct vga_device *vgadev; |
504 | unsigned long flags; |
505 | int rc = 0; |
506 | |
507 | vga_check_first_use(); |
508 | |
509 | /* The caller should check for this, but let's be sure */ |
510 | if (pdev == NULL) |
511 | pdev = vga_default_device(); |
512 | if (pdev == NULL) |
513 | return 0; |
514 | spin_lock_irqsave(&vga_lock, flags); |
515 | vgadev = vgadev_find(pdev); |
516 | if (vgadev == NULL) { |
517 | rc = -ENODEV; |
518 | goto bail; |
519 | } |
520 | if (__vga_tryget(vgadev, rsrc)) |
521 | rc = -EBUSY; |
522 | bail: |
523 | spin_unlock_irqrestore(lock: &vga_lock, flags); |
524 | return rc; |
525 | } |
526 | |
527 | /** |
528 | * vga_put - release lock on legacy VGA resources |
529 | * @pdev: PCI device of VGA card or NULL for system default |
530 | * @rsrc: bit mask of resource to release |
531 | * |
532 | * Release resources previously locked by vga_get() or vga_tryget(). The |
533 | * resources aren't disabled right away, so that a subsequent vga_get() on |
534 | * the same card will succeed immediately. Resources have a counter, so |
535 | * locks are only released if the counter reaches 0. |
536 | */ |
537 | void vga_put(struct pci_dev *pdev, unsigned int rsrc) |
538 | { |
539 | struct vga_device *vgadev; |
540 | unsigned long flags; |
541 | |
542 | /* The caller should check for this, but let's be sure */ |
543 | if (pdev == NULL) |
544 | pdev = vga_default_device(); |
545 | if (pdev == NULL) |
546 | return; |
547 | spin_lock_irqsave(&vga_lock, flags); |
548 | vgadev = vgadev_find(pdev); |
549 | if (vgadev == NULL) |
550 | goto bail; |
551 | __vga_put(vgadev, rsrc); |
552 | bail: |
553 | spin_unlock_irqrestore(lock: &vga_lock, flags); |
554 | } |
555 | EXPORT_SYMBOL(vga_put); |
556 | |
557 | static bool vga_is_firmware_default(struct pci_dev *pdev) |
558 | { |
559 | #if defined(CONFIG_X86) |
560 | u64 base = screen_info.lfb_base; |
561 | u64 size = screen_info.lfb_size; |
562 | struct resource *r; |
563 | u64 limit; |
564 | |
565 | /* Select the device owning the boot framebuffer if there is one */ |
566 | |
567 | if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) |
568 | base |= (u64)screen_info.ext_lfb_base << 32; |
569 | |
570 | limit = base + size; |
571 | |
572 | /* Does firmware framebuffer belong to us? */ |
573 | pci_dev_for_each_resource(pdev, r) { |
574 | if (resource_type(res: r) != IORESOURCE_MEM) |
575 | continue; |
576 | |
577 | if (!r->start || !r->end) |
578 | continue; |
579 | |
580 | if (base < r->start || limit >= r->end) |
581 | continue; |
582 | |
583 | return true; |
584 | } |
585 | #endif |
586 | return false; |
587 | } |
588 | |
589 | static bool vga_arb_integrated_gpu(struct device *dev) |
590 | { |
591 | #if defined(CONFIG_ACPI) |
592 | struct acpi_device *adev = ACPI_COMPANION(dev); |
593 | |
594 | return adev && !strcmp(acpi_device_hid(device: adev), ACPI_VIDEO_HID); |
595 | #else |
596 | return false; |
597 | #endif |
598 | } |
599 | |
600 | /* |
601 | * Return true if vgadev is a better default VGA device than the best one |
602 | * we've seen so far. |
603 | */ |
604 | static bool vga_is_boot_device(struct vga_device *vgadev) |
605 | { |
606 | struct vga_device *boot_vga = vgadev_find(pdev: vga_default_device()); |
607 | struct pci_dev *pdev = vgadev->pdev; |
608 | u16 cmd, boot_cmd; |
609 | |
610 | /* |
611 | * We select the default VGA device in this order: |
612 | * Firmware framebuffer (see vga_arb_select_default_device()) |
613 | * Legacy VGA device (owns VGA_RSRC_LEGACY_MASK) |
614 | * Non-legacy integrated device (see vga_arb_select_default_device()) |
615 | * Non-legacy discrete device (see vga_arb_select_default_device()) |
616 | * Other device (see vga_arb_select_default_device()) |
617 | */ |
618 | |
619 | /* |
620 | * We always prefer a firmware default device, so if we've already |
621 | * found one, there's no need to consider vgadev. |
622 | */ |
623 | if (boot_vga && boot_vga->is_firmware_default) |
624 | return false; |
625 | |
626 | if (vga_is_firmware_default(pdev)) { |
627 | vgadev->is_firmware_default = true; |
628 | return true; |
629 | } |
630 | |
631 | /* |
632 | * A legacy VGA device has MEM and IO enabled and any bridges |
633 | * leading to it have PCI_BRIDGE_CTL_VGA enabled so the legacy |
634 | * resources ([mem 0xa0000-0xbffff], [io 0x3b0-0x3bb], etc) are |
635 | * routed to it. |
636 | * |
637 | * We use the first one we find, so if we've already found one, |
638 | * vgadev is no better. |
639 | */ |
640 | if (boot_vga && |
641 | (boot_vga->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK) |
642 | return false; |
643 | |
644 | if ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK) |
645 | return true; |
646 | |
647 | /* |
648 | * If we haven't found a legacy VGA device, accept a non-legacy |
649 | * device. It may have either IO or MEM enabled, and bridges may |
650 | * not have PCI_BRIDGE_CTL_VGA enabled, so it may not be able to |
651 | * use legacy VGA resources. Prefer an integrated GPU over others. |
652 | */ |
653 | pci_read_config_word(dev: pdev, PCI_COMMAND, val: &cmd); |
654 | if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) { |
655 | |
656 | /* |
657 | * An integrated GPU overrides a previous non-legacy |
658 | * device. We expect only a single integrated GPU, but if |
659 | * there are more, we use the *last* because that was the |
660 | * previous behavior. |
661 | */ |
662 | if (vga_arb_integrated_gpu(dev: &pdev->dev)) |
663 | return true; |
664 | |
665 | /* |
666 | * We prefer the first non-legacy discrete device we find. |
667 | * If we already found one, vgadev is no better. |
668 | */ |
669 | if (boot_vga) { |
670 | pci_read_config_word(dev: boot_vga->pdev, PCI_COMMAND, |
671 | val: &boot_cmd); |
672 | if (boot_cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) |
673 | return false; |
674 | } |
675 | return true; |
676 | } |
677 | |
678 | /* |
679 | * Vgadev has neither IO nor MEM enabled. If we haven't found any |
680 | * other VGA devices, it is the best candidate so far. |
681 | */ |
682 | if (!boot_vga) |
683 | return true; |
684 | |
685 | return false; |
686 | } |
687 | |
688 | /* |
689 | * Rules for using a bridge to control a VGA descendant decoding: if a bridge |
690 | * has only one VGA descendant then it can be used to control the VGA routing |
691 | * for that device. It should always use the bridge closest to the device to |
692 | * control it. If a bridge has a direct VGA descendant, but also have a sub- |
693 | * bridge VGA descendant then we cannot use that bridge to control the direct |
694 | * VGA descendant. So for every device we register, we need to iterate all |
695 | * its parent bridges so we can invalidate any devices using them properly. |
696 | */ |
697 | static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev) |
698 | { |
699 | struct vga_device *same_bridge_vgadev; |
700 | struct pci_bus *new_bus, *bus; |
701 | struct pci_dev *new_bridge, *bridge; |
702 | |
703 | vgadev->bridge_has_one_vga = true; |
704 | |
705 | if (list_empty(head: &vga_list)) { |
706 | vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n" ); |
707 | return; |
708 | } |
709 | |
710 | /* Iterate the new device's bridge hierarchy */ |
711 | new_bus = vgadev->pdev->bus; |
712 | while (new_bus) { |
713 | new_bridge = new_bus->self; |
714 | |
715 | /* Go through list of devices already registered */ |
716 | list_for_each_entry(same_bridge_vgadev, &vga_list, list) { |
717 | bus = same_bridge_vgadev->pdev->bus; |
718 | bridge = bus->self; |
719 | |
720 | /* See if it shares a bridge with this device */ |
721 | if (new_bridge == bridge) { |
722 | /* |
723 | * If its direct parent bridge is the same |
724 | * as any bridge of this device then it can't |
725 | * be used for that device. |
726 | */ |
727 | same_bridge_vgadev->bridge_has_one_vga = false; |
728 | } |
729 | |
730 | /* |
731 | * Now iterate the previous device's bridge hierarchy. |
732 | * If the new device's parent bridge is in the other |
733 | * device's hierarchy, we can't use it to control this |
734 | * device. |
735 | */ |
736 | while (bus) { |
737 | bridge = bus->self; |
738 | |
739 | if (bridge && bridge == vgadev->pdev->bus->self) |
740 | vgadev->bridge_has_one_vga = false; |
741 | |
742 | bus = bus->parent; |
743 | } |
744 | } |
745 | new_bus = new_bus->parent; |
746 | } |
747 | |
748 | if (vgadev->bridge_has_one_vga) |
749 | vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n" ); |
750 | else |
751 | vgaarb_info(&vgadev->pdev->dev, "no bridge control possible\n" ); |
752 | } |
753 | |
754 | /* |
755 | * Currently, we assume that the "initial" setup of the system is not sane, |
756 | * that is, we come up with conflicting devices and let the arbiter's |
757 | * client decide if devices decodes legacy things or not. |
758 | */ |
759 | static bool vga_arbiter_add_pci_device(struct pci_dev *pdev) |
760 | { |
761 | struct vga_device *vgadev; |
762 | unsigned long flags; |
763 | struct pci_bus *bus; |
764 | struct pci_dev *bridge; |
765 | u16 cmd; |
766 | |
767 | /* Allocate structure */ |
768 | vgadev = kzalloc(size: sizeof(struct vga_device), GFP_KERNEL); |
769 | if (vgadev == NULL) { |
770 | vgaarb_err(&pdev->dev, "failed to allocate VGA arbiter data\n" ); |
771 | /* |
772 | * What to do on allocation failure? For now, let's just do |
773 | * nothing, I'm not sure there is anything saner to be done. |
774 | */ |
775 | return false; |
776 | } |
777 | |
778 | /* Take lock & check for duplicates */ |
779 | spin_lock_irqsave(&vga_lock, flags); |
780 | if (vgadev_find(pdev) != NULL) { |
781 | BUG_ON(1); |
782 | goto fail; |
783 | } |
784 | vgadev->pdev = pdev; |
785 | |
786 | /* By default, assume we decode everything */ |
787 | vgadev->decodes = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM | |
788 | VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM; |
789 | |
790 | /* By default, mark it as decoding */ |
791 | vga_decode_count++; |
792 | |
793 | /* |
794 | * Mark that we "own" resources based on our enables, we will |
795 | * clear that below if the bridge isn't forwarding. |
796 | */ |
797 | pci_read_config_word(dev: pdev, PCI_COMMAND, val: &cmd); |
798 | if (cmd & PCI_COMMAND_IO) |
799 | vgadev->owns |= VGA_RSRC_LEGACY_IO; |
800 | if (cmd & PCI_COMMAND_MEMORY) |
801 | vgadev->owns |= VGA_RSRC_LEGACY_MEM; |
802 | |
803 | /* Check if VGA cycles can get down to us */ |
804 | bus = pdev->bus; |
805 | while (bus) { |
806 | bridge = bus->self; |
807 | if (bridge) { |
808 | u16 l; |
809 | |
810 | pci_read_config_word(dev: bridge, PCI_BRIDGE_CONTROL, val: &l); |
811 | if (!(l & PCI_BRIDGE_CTL_VGA)) { |
812 | vgadev->owns = 0; |
813 | break; |
814 | } |
815 | } |
816 | bus = bus->parent; |
817 | } |
818 | |
819 | if (vga_is_boot_device(vgadev)) { |
820 | vgaarb_info(&pdev->dev, "setting as boot VGA device%s\n" , |
821 | vga_default_device() ? |
822 | " (overriding previous)" : "" ); |
823 | vga_set_default_device(pdev); |
824 | } |
825 | |
826 | vga_arbiter_check_bridge_sharing(vgadev); |
827 | |
828 | /* Add to the list */ |
829 | list_add_tail(new: &vgadev->list, head: &vga_list); |
830 | vga_count++; |
831 | vgaarb_info(&pdev->dev, "VGA device added: decodes=%s,owns=%s,locks=%s\n" , |
832 | vga_iostate_to_str(vgadev->decodes), |
833 | vga_iostate_to_str(vgadev->owns), |
834 | vga_iostate_to_str(vgadev->locks)); |
835 | |
836 | spin_unlock_irqrestore(lock: &vga_lock, flags); |
837 | return true; |
838 | fail: |
839 | spin_unlock_irqrestore(lock: &vga_lock, flags); |
840 | kfree(objp: vgadev); |
841 | return false; |
842 | } |
843 | |
844 | static bool vga_arbiter_del_pci_device(struct pci_dev *pdev) |
845 | { |
846 | struct vga_device *vgadev; |
847 | unsigned long flags; |
848 | bool ret = true; |
849 | |
850 | spin_lock_irqsave(&vga_lock, flags); |
851 | vgadev = vgadev_find(pdev); |
852 | if (vgadev == NULL) { |
853 | ret = false; |
854 | goto bail; |
855 | } |
856 | |
857 | if (vga_default == pdev) |
858 | vga_set_default_device(NULL); |
859 | |
860 | if (vgadev->decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM)) |
861 | vga_decode_count--; |
862 | |
863 | /* Remove entry from list */ |
864 | list_del(entry: &vgadev->list); |
865 | vga_count--; |
866 | |
867 | /* Wake up all possible waiters */ |
868 | wake_up_all(&vga_wait_queue); |
869 | bail: |
870 | spin_unlock_irqrestore(lock: &vga_lock, flags); |
871 | kfree(objp: vgadev); |
872 | return ret; |
873 | } |
874 | |
875 | /* Called with the lock */ |
876 | static void vga_update_device_decodes(struct vga_device *vgadev, |
877 | unsigned int new_decodes) |
878 | { |
879 | struct device *dev = &vgadev->pdev->dev; |
880 | unsigned int old_decodes = vgadev->decodes; |
881 | unsigned int decodes_removed = ~new_decodes & old_decodes; |
882 | unsigned int decodes_unlocked = vgadev->locks & decodes_removed; |
883 | |
884 | vgadev->decodes = new_decodes; |
885 | |
886 | vgaarb_info(dev, "VGA decodes changed: olddecodes=%s,decodes=%s:owns=%s\n" , |
887 | vga_iostate_to_str(old_decodes), |
888 | vga_iostate_to_str(vgadev->decodes), |
889 | vga_iostate_to_str(vgadev->owns)); |
890 | |
891 | /* If we removed locked decodes, lock count goes to zero, and release */ |
892 | if (decodes_unlocked) { |
893 | if (decodes_unlocked & VGA_RSRC_LEGACY_IO) |
894 | vgadev->io_lock_cnt = 0; |
895 | if (decodes_unlocked & VGA_RSRC_LEGACY_MEM) |
896 | vgadev->mem_lock_cnt = 0; |
897 | __vga_put(vgadev, rsrc: decodes_unlocked); |
898 | } |
899 | |
900 | /* Change decodes counter */ |
901 | if (old_decodes & VGA_RSRC_LEGACY_MASK && |
902 | !(new_decodes & VGA_RSRC_LEGACY_MASK)) |
903 | vga_decode_count--; |
904 | if (!(old_decodes & VGA_RSRC_LEGACY_MASK) && |
905 | new_decodes & VGA_RSRC_LEGACY_MASK) |
906 | vga_decode_count++; |
907 | vgaarb_dbg(dev, "decoding count now is: %d\n" , vga_decode_count); |
908 | } |
909 | |
910 | static void __vga_set_legacy_decoding(struct pci_dev *pdev, |
911 | unsigned int decodes, |
912 | bool userspace) |
913 | { |
914 | struct vga_device *vgadev; |
915 | unsigned long flags; |
916 | |
917 | decodes &= VGA_RSRC_LEGACY_MASK; |
918 | |
919 | spin_lock_irqsave(&vga_lock, flags); |
920 | vgadev = vgadev_find(pdev); |
921 | if (vgadev == NULL) |
922 | goto bail; |
923 | |
924 | /* Don't let userspace futz with kernel driver decodes */ |
925 | if (userspace && vgadev->set_decode) |
926 | goto bail; |
927 | |
928 | /* Update the device decodes + counter */ |
929 | vga_update_device_decodes(vgadev, new_decodes: decodes); |
930 | |
931 | /* |
932 | * XXX If somebody is going from "doesn't decode" to "decodes" |
933 | * state here, additional care must be taken as we may have pending |
934 | * ownership of non-legacy region. |
935 | */ |
936 | bail: |
937 | spin_unlock_irqrestore(lock: &vga_lock, flags); |
938 | } |
939 | |
940 | /** |
941 | * vga_set_legacy_decoding |
942 | * @pdev: PCI device of the VGA card |
943 | * @decodes: bit mask of what legacy regions the card decodes |
944 | * |
945 | * Indicate to the arbiter if the card decodes legacy VGA IOs, legacy VGA |
946 | * Memory, both, or none. All cards default to both, the card driver (fbdev for |
947 | * example) should tell the arbiter if it has disabled legacy decoding, so the |
948 | * card can be left out of the arbitration process (and can be safe to take |
949 | * interrupts at any time. |
950 | */ |
951 | void vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes) |
952 | { |
953 | __vga_set_legacy_decoding(pdev, decodes, userspace: false); |
954 | } |
955 | EXPORT_SYMBOL(vga_set_legacy_decoding); |
956 | |
957 | /** |
958 | * vga_client_register - register or unregister a VGA arbitration client |
959 | * @pdev: PCI device of the VGA client |
960 | * @set_decode: VGA decode change callback |
961 | * |
962 | * Clients have two callback mechanisms they can use. |
963 | * |
964 | * @set_decode callback: If a client can disable its GPU VGA resource, it |
965 | * will get a callback from this to set the encode/decode state. |
966 | * |
967 | * Rationale: we cannot disable VGA decode resources unconditionally |
968 | * because some single GPU laptops seem to require ACPI or BIOS access to |
969 | * the VGA registers to control things like backlights etc. Hopefully newer |
970 | * multi-GPU laptops do something saner, and desktops won't have any |
971 | * special ACPI for this. The driver will get a callback when VGA |
972 | * arbitration is first used by userspace since some older X servers have |
973 | * issues. |
974 | * |
975 | * Does not check whether a client for @pdev has been registered already. |
976 | * |
977 | * To unregister, call vga_client_unregister(). |
978 | * |
979 | * Returns: 0 on success, -ENODEV on failure |
980 | */ |
981 | int vga_client_register(struct pci_dev *pdev, |
982 | unsigned int (*set_decode)(struct pci_dev *pdev, bool decode)) |
983 | { |
984 | unsigned long flags; |
985 | struct vga_device *vgadev; |
986 | |
987 | spin_lock_irqsave(&vga_lock, flags); |
988 | vgadev = vgadev_find(pdev); |
989 | if (vgadev) |
990 | vgadev->set_decode = set_decode; |
991 | spin_unlock_irqrestore(lock: &vga_lock, flags); |
992 | if (!vgadev) |
993 | return -ENODEV; |
994 | return 0; |
995 | } |
996 | EXPORT_SYMBOL(vga_client_register); |
997 | |
998 | /* |
999 | * Char driver implementation |
1000 | * |
1001 | * Semantics is: |
1002 | * |
1003 | * open : Open user instance of the arbiter. By default, it's |
1004 | * attached to the default VGA device of the system. |
1005 | * |
1006 | * close : Close user instance, release locks |
1007 | * |
1008 | * read : Return a string indicating the status of the target. |
1009 | * An IO state string is of the form {io,mem,io+mem,none}, |
1010 | * mc and ic are respectively mem and io lock counts (for |
1011 | * debugging/diagnostic only). "decodes" indicate what the |
1012 | * card currently decodes, "owns" indicates what is currently |
1013 | * enabled on it, and "locks" indicates what is locked by this |
1014 | * card. If the card is unplugged, we get "invalid" then for |
1015 | * card_ID and an -ENODEV error is returned for any command |
1016 | * until a new card is targeted |
1017 | * |
1018 | * "<card_ID>,decodes=<io_state>,owns=<io_state>,locks=<io_state> (ic,mc)" |
1019 | * |
1020 | * write : write a command to the arbiter. List of commands is: |
1021 | * |
1022 | * target <card_ID> : switch target to card <card_ID> (see below) |
1023 | * lock <io_state> : acquire locks on target ("none" is invalid io_state) |
1024 | * trylock <io_state> : non-blocking acquire locks on target |
1025 | * unlock <io_state> : release locks on target |
1026 | * unlock all : release all locks on target held by this user |
1027 | * decodes <io_state> : set the legacy decoding attributes for the card |
1028 | * |
1029 | * poll : event if something change on any card (not just the target) |
1030 | * |
1031 | * card_ID is of the form "PCI:domain:bus:dev.fn". It can be set to "default" |
1032 | * to go back to the system default card (TODO: not implemented yet). |
1033 | * Currently, only PCI is supported as a prefix, but the userland API may |
1034 | * support other bus types in the future, even if the current kernel |
1035 | * implementation doesn't. |
1036 | * |
1037 | * Note about locks: |
1038 | * |
1039 | * The driver keeps track of which user has what locks on which card. It |
1040 | * supports stacking, like the kernel one. This complicates the implementation |
1041 | * a bit, but makes the arbiter more tolerant to userspace problems and able |
1042 | * to properly cleanup in all cases when a process dies. |
1043 | * Currently, a max of 16 cards simultaneously can have locks issued from |
1044 | * userspace for a given user (file descriptor instance) of the arbiter. |
1045 | * |
1046 | * If the device is hot-unplugged, there is a hook inside the module to notify |
1047 | * it being added/removed in the system and automatically added/removed in |
1048 | * the arbiter. |
1049 | */ |
1050 | |
1051 | #define MAX_USER_CARDS CONFIG_VGA_ARB_MAX_GPUS |
1052 | #define PCI_INVALID_CARD ((struct pci_dev *)-1UL) |
1053 | |
1054 | /* Each user has an array of these, tracking which cards have locks */ |
1055 | struct vga_arb_user_card { |
1056 | struct pci_dev *pdev; |
1057 | unsigned int mem_cnt; |
1058 | unsigned int io_cnt; |
1059 | }; |
1060 | |
1061 | struct vga_arb_private { |
1062 | struct list_head list; |
1063 | struct pci_dev *target; |
1064 | struct vga_arb_user_card cards[MAX_USER_CARDS]; |
1065 | spinlock_t lock; |
1066 | }; |
1067 | |
1068 | static LIST_HEAD(vga_user_list); |
1069 | static DEFINE_SPINLOCK(vga_user_lock); |
1070 | |
1071 | |
1072 | /* |
1073 | * Take a string in the format: "PCI:domain:bus:dev.fn" and return the |
1074 | * respective values. If the string is not in this format, return 0. |
1075 | */ |
1076 | static int vga_pci_str_to_vars(char *buf, int count, unsigned int *domain, |
1077 | unsigned int *bus, unsigned int *devfn) |
1078 | { |
1079 | int n; |
1080 | unsigned int slot, func; |
1081 | |
1082 | n = sscanf(buf, "PCI:%x:%x:%x.%x" , domain, bus, &slot, &func); |
1083 | if (n != 4) |
1084 | return 0; |
1085 | |
1086 | *devfn = PCI_DEVFN(slot, func); |
1087 | |
1088 | return 1; |
1089 | } |
1090 | |
1091 | static ssize_t vga_arb_read(struct file *file, char __user *buf, |
1092 | size_t count, loff_t *ppos) |
1093 | { |
1094 | struct vga_arb_private *priv = file->private_data; |
1095 | struct vga_device *vgadev; |
1096 | struct pci_dev *pdev; |
1097 | unsigned long flags; |
1098 | size_t len; |
1099 | int rc; |
1100 | char *lbuf; |
1101 | |
1102 | lbuf = kmalloc(size: 1024, GFP_KERNEL); |
1103 | if (lbuf == NULL) |
1104 | return -ENOMEM; |
1105 | |
1106 | /* Protect vga_list */ |
1107 | spin_lock_irqsave(&vga_lock, flags); |
1108 | |
1109 | /* If we are targeting the default, use it */ |
1110 | pdev = priv->target; |
1111 | if (pdev == NULL || pdev == PCI_INVALID_CARD) { |
1112 | spin_unlock_irqrestore(lock: &vga_lock, flags); |
1113 | len = sprintf(buf: lbuf, fmt: "invalid" ); |
1114 | goto done; |
1115 | } |
1116 | |
1117 | /* Find card vgadev structure */ |
1118 | vgadev = vgadev_find(pdev); |
1119 | if (vgadev == NULL) { |
1120 | /* |
1121 | * Wow, it's not in the list, that shouldn't happen, let's |
1122 | * fix us up and return invalid card. |
1123 | */ |
1124 | spin_unlock_irqrestore(lock: &vga_lock, flags); |
1125 | len = sprintf(buf: lbuf, fmt: "invalid" ); |
1126 | goto done; |
1127 | } |
1128 | |
1129 | /* Fill the buffer with info */ |
1130 | len = snprintf(buf: lbuf, size: 1024, |
1131 | fmt: "count:%d,PCI:%s,decodes=%s,owns=%s,locks=%s(%u:%u)\n" , |
1132 | vga_decode_count, pci_name(pdev), |
1133 | vga_iostate_to_str(iostate: vgadev->decodes), |
1134 | vga_iostate_to_str(iostate: vgadev->owns), |
1135 | vga_iostate_to_str(iostate: vgadev->locks), |
1136 | vgadev->io_lock_cnt, vgadev->mem_lock_cnt); |
1137 | |
1138 | spin_unlock_irqrestore(lock: &vga_lock, flags); |
1139 | done: |
1140 | |
1141 | /* Copy that to user */ |
1142 | if (len > count) |
1143 | len = count; |
1144 | rc = copy_to_user(to: buf, from: lbuf, n: len); |
1145 | kfree(objp: lbuf); |
1146 | if (rc) |
1147 | return -EFAULT; |
1148 | return len; |
1149 | } |
1150 | |
1151 | /* |
1152 | * TODO: To avoid parsing inside kernel and to improve the speed we may |
1153 | * consider use ioctl here |
1154 | */ |
1155 | static ssize_t vga_arb_write(struct file *file, const char __user *buf, |
1156 | size_t count, loff_t *ppos) |
1157 | { |
1158 | struct vga_arb_private *priv = file->private_data; |
1159 | struct vga_arb_user_card *uc = NULL; |
1160 | struct pci_dev *pdev; |
1161 | |
1162 | unsigned int io_state; |
1163 | |
1164 | char kbuf[64], *curr_pos; |
1165 | size_t remaining = count; |
1166 | |
1167 | int ret_val; |
1168 | int i; |
1169 | |
1170 | if (count >= sizeof(kbuf)) |
1171 | return -EINVAL; |
1172 | if (copy_from_user(to: kbuf, from: buf, n: count)) |
1173 | return -EFAULT; |
1174 | curr_pos = kbuf; |
1175 | kbuf[count] = '\0'; |
1176 | |
1177 | if (strncmp(curr_pos, "lock " , 5) == 0) { |
1178 | curr_pos += 5; |
1179 | remaining -= 5; |
1180 | |
1181 | pr_debug("client 0x%p called 'lock'\n" , priv); |
1182 | |
1183 | if (!vga_str_to_iostate(buf: curr_pos, str_size: remaining, io_state: &io_state)) { |
1184 | ret_val = -EPROTO; |
1185 | goto done; |
1186 | } |
1187 | if (io_state == VGA_RSRC_NONE) { |
1188 | ret_val = -EPROTO; |
1189 | goto done; |
1190 | } |
1191 | |
1192 | pdev = priv->target; |
1193 | if (priv->target == NULL) { |
1194 | ret_val = -ENODEV; |
1195 | goto done; |
1196 | } |
1197 | |
1198 | vga_get_uninterruptible(pdev, rsrc: io_state); |
1199 | |
1200 | /* Update the client's locks lists */ |
1201 | for (i = 0; i < MAX_USER_CARDS; i++) { |
1202 | if (priv->cards[i].pdev == pdev) { |
1203 | if (io_state & VGA_RSRC_LEGACY_IO) |
1204 | priv->cards[i].io_cnt++; |
1205 | if (io_state & VGA_RSRC_LEGACY_MEM) |
1206 | priv->cards[i].mem_cnt++; |
1207 | break; |
1208 | } |
1209 | } |
1210 | |
1211 | ret_val = count; |
1212 | goto done; |
1213 | } else if (strncmp(curr_pos, "unlock " , 7) == 0) { |
1214 | curr_pos += 7; |
1215 | remaining -= 7; |
1216 | |
1217 | pr_debug("client 0x%p called 'unlock'\n" , priv); |
1218 | |
1219 | if (strncmp(curr_pos, "all" , 3) == 0) |
1220 | io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; |
1221 | else { |
1222 | if (!vga_str_to_iostate |
1223 | (buf: curr_pos, str_size: remaining, io_state: &io_state)) { |
1224 | ret_val = -EPROTO; |
1225 | goto done; |
1226 | } |
1227 | /* TODO: Add this? |
1228 | if (io_state == VGA_RSRC_NONE) { |
1229 | ret_val = -EPROTO; |
1230 | goto done; |
1231 | } |
1232 | */ |
1233 | } |
1234 | |
1235 | pdev = priv->target; |
1236 | if (priv->target == NULL) { |
1237 | ret_val = -ENODEV; |
1238 | goto done; |
1239 | } |
1240 | for (i = 0; i < MAX_USER_CARDS; i++) { |
1241 | if (priv->cards[i].pdev == pdev) |
1242 | uc = &priv->cards[i]; |
1243 | } |
1244 | |
1245 | if (!uc) { |
1246 | ret_val = -EINVAL; |
1247 | goto done; |
1248 | } |
1249 | |
1250 | if (io_state & VGA_RSRC_LEGACY_IO && uc->io_cnt == 0) { |
1251 | ret_val = -EINVAL; |
1252 | goto done; |
1253 | } |
1254 | |
1255 | if (io_state & VGA_RSRC_LEGACY_MEM && uc->mem_cnt == 0) { |
1256 | ret_val = -EINVAL; |
1257 | goto done; |
1258 | } |
1259 | |
1260 | vga_put(pdev, io_state); |
1261 | |
1262 | if (io_state & VGA_RSRC_LEGACY_IO) |
1263 | uc->io_cnt--; |
1264 | if (io_state & VGA_RSRC_LEGACY_MEM) |
1265 | uc->mem_cnt--; |
1266 | |
1267 | ret_val = count; |
1268 | goto done; |
1269 | } else if (strncmp(curr_pos, "trylock " , 8) == 0) { |
1270 | curr_pos += 8; |
1271 | remaining -= 8; |
1272 | |
1273 | pr_debug("client 0x%p called 'trylock'\n" , priv); |
1274 | |
1275 | if (!vga_str_to_iostate(buf: curr_pos, str_size: remaining, io_state: &io_state)) { |
1276 | ret_val = -EPROTO; |
1277 | goto done; |
1278 | } |
1279 | /* TODO: Add this? |
1280 | if (io_state == VGA_RSRC_NONE) { |
1281 | ret_val = -EPROTO; |
1282 | goto done; |
1283 | } |
1284 | */ |
1285 | |
1286 | pdev = priv->target; |
1287 | if (priv->target == NULL) { |
1288 | ret_val = -ENODEV; |
1289 | goto done; |
1290 | } |
1291 | |
1292 | if (vga_tryget(pdev, rsrc: io_state)) { |
1293 | /* Update the client's locks lists... */ |
1294 | for (i = 0; i < MAX_USER_CARDS; i++) { |
1295 | if (priv->cards[i].pdev == pdev) { |
1296 | if (io_state & VGA_RSRC_LEGACY_IO) |
1297 | priv->cards[i].io_cnt++; |
1298 | if (io_state & VGA_RSRC_LEGACY_MEM) |
1299 | priv->cards[i].mem_cnt++; |
1300 | break; |
1301 | } |
1302 | } |
1303 | ret_val = count; |
1304 | goto done; |
1305 | } else { |
1306 | ret_val = -EBUSY; |
1307 | goto done; |
1308 | } |
1309 | |
1310 | } else if (strncmp(curr_pos, "target " , 7) == 0) { |
1311 | unsigned int domain, bus, devfn; |
1312 | struct vga_device *vgadev; |
1313 | |
1314 | curr_pos += 7; |
1315 | remaining -= 7; |
1316 | pr_debug("client 0x%p called 'target'\n" , priv); |
1317 | /* If target is default */ |
1318 | if (!strncmp(curr_pos, "default" , 7)) |
1319 | pdev = pci_dev_get(dev: vga_default_device()); |
1320 | else { |
1321 | if (!vga_pci_str_to_vars(buf: curr_pos, count: remaining, |
1322 | domain: &domain, bus: &bus, devfn: &devfn)) { |
1323 | ret_val = -EPROTO; |
1324 | goto done; |
1325 | } |
1326 | pdev = pci_get_domain_bus_and_slot(domain, bus, devfn); |
1327 | if (!pdev) { |
1328 | pr_debug("invalid PCI address %04x:%02x:%02x.%x\n" , |
1329 | domain, bus, PCI_SLOT(devfn), |
1330 | PCI_FUNC(devfn)); |
1331 | ret_val = -ENODEV; |
1332 | goto done; |
1333 | } |
1334 | |
1335 | pr_debug("%s ==> %04x:%02x:%02x.%x pdev %p\n" , curr_pos, |
1336 | domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn), |
1337 | pdev); |
1338 | } |
1339 | |
1340 | vgadev = vgadev_find(pdev); |
1341 | pr_debug("vgadev %p\n" , vgadev); |
1342 | if (vgadev == NULL) { |
1343 | if (pdev) { |
1344 | vgaarb_dbg(&pdev->dev, "not a VGA device\n" ); |
1345 | pci_dev_put(dev: pdev); |
1346 | } |
1347 | |
1348 | ret_val = -ENODEV; |
1349 | goto done; |
1350 | } |
1351 | |
1352 | priv->target = pdev; |
1353 | for (i = 0; i < MAX_USER_CARDS; i++) { |
1354 | if (priv->cards[i].pdev == pdev) |
1355 | break; |
1356 | if (priv->cards[i].pdev == NULL) { |
1357 | priv->cards[i].pdev = pdev; |
1358 | priv->cards[i].io_cnt = 0; |
1359 | priv->cards[i].mem_cnt = 0; |
1360 | break; |
1361 | } |
1362 | } |
1363 | if (i == MAX_USER_CARDS) { |
1364 | vgaarb_dbg(&pdev->dev, "maximum user cards (%d) number reached, ignoring this one!\n" , |
1365 | MAX_USER_CARDS); |
1366 | pci_dev_put(dev: pdev); |
1367 | /* XXX: Which value to return? */ |
1368 | ret_val = -ENOMEM; |
1369 | goto done; |
1370 | } |
1371 | |
1372 | ret_val = count; |
1373 | pci_dev_put(dev: pdev); |
1374 | goto done; |
1375 | |
1376 | |
1377 | } else if (strncmp(curr_pos, "decodes " , 8) == 0) { |
1378 | curr_pos += 8; |
1379 | remaining -= 8; |
1380 | pr_debug("client 0x%p called 'decodes'\n" , priv); |
1381 | |
1382 | if (!vga_str_to_iostate(buf: curr_pos, str_size: remaining, io_state: &io_state)) { |
1383 | ret_val = -EPROTO; |
1384 | goto done; |
1385 | } |
1386 | pdev = priv->target; |
1387 | if (priv->target == NULL) { |
1388 | ret_val = -ENODEV; |
1389 | goto done; |
1390 | } |
1391 | |
1392 | __vga_set_legacy_decoding(pdev, decodes: io_state, userspace: true); |
1393 | ret_val = count; |
1394 | goto done; |
1395 | } |
1396 | /* If we got here, the message written is not part of the protocol! */ |
1397 | return -EPROTO; |
1398 | |
1399 | done: |
1400 | return ret_val; |
1401 | } |
1402 | |
1403 | static __poll_t vga_arb_fpoll(struct file *file, poll_table *wait) |
1404 | { |
1405 | pr_debug("%s\n" , __func__); |
1406 | |
1407 | poll_wait(filp: file, wait_address: &vga_wait_queue, p: wait); |
1408 | return EPOLLIN; |
1409 | } |
1410 | |
1411 | static int vga_arb_open(struct inode *inode, struct file *file) |
1412 | { |
1413 | struct vga_arb_private *priv; |
1414 | unsigned long flags; |
1415 | |
1416 | pr_debug("%s\n" , __func__); |
1417 | |
1418 | priv = kzalloc(size: sizeof(*priv), GFP_KERNEL); |
1419 | if (priv == NULL) |
1420 | return -ENOMEM; |
1421 | spin_lock_init(&priv->lock); |
1422 | file->private_data = priv; |
1423 | |
1424 | spin_lock_irqsave(&vga_user_lock, flags); |
1425 | list_add(new: &priv->list, head: &vga_user_list); |
1426 | spin_unlock_irqrestore(lock: &vga_user_lock, flags); |
1427 | |
1428 | /* Set the client's lists of locks */ |
1429 | priv->target = vga_default_device(); /* Maybe this is still null! */ |
1430 | priv->cards[0].pdev = priv->target; |
1431 | priv->cards[0].io_cnt = 0; |
1432 | priv->cards[0].mem_cnt = 0; |
1433 | |
1434 | return 0; |
1435 | } |
1436 | |
1437 | static int vga_arb_release(struct inode *inode, struct file *file) |
1438 | { |
1439 | struct vga_arb_private *priv = file->private_data; |
1440 | struct vga_arb_user_card *uc; |
1441 | unsigned long flags; |
1442 | int i; |
1443 | |
1444 | pr_debug("%s\n" , __func__); |
1445 | |
1446 | spin_lock_irqsave(&vga_user_lock, flags); |
1447 | list_del(entry: &priv->list); |
1448 | for (i = 0; i < MAX_USER_CARDS; i++) { |
1449 | uc = &priv->cards[i]; |
1450 | if (uc->pdev == NULL) |
1451 | continue; |
1452 | vgaarb_dbg(&uc->pdev->dev, "uc->io_cnt == %d, uc->mem_cnt == %d\n" , |
1453 | uc->io_cnt, uc->mem_cnt); |
1454 | while (uc->io_cnt--) |
1455 | vga_put(uc->pdev, VGA_RSRC_LEGACY_IO); |
1456 | while (uc->mem_cnt--) |
1457 | vga_put(uc->pdev, VGA_RSRC_LEGACY_MEM); |
1458 | } |
1459 | spin_unlock_irqrestore(lock: &vga_user_lock, flags); |
1460 | |
1461 | kfree(objp: priv); |
1462 | |
1463 | return 0; |
1464 | } |
1465 | |
1466 | /* |
1467 | * Callback any registered clients to let them know we have a change in VGA |
1468 | * cards. |
1469 | */ |
1470 | static void vga_arbiter_notify_clients(void) |
1471 | { |
1472 | struct vga_device *vgadev; |
1473 | unsigned long flags; |
1474 | unsigned int new_decodes; |
1475 | bool new_state; |
1476 | |
1477 | if (!vga_arbiter_used) |
1478 | return; |
1479 | |
1480 | new_state = (vga_count > 1) ? false : true; |
1481 | |
1482 | spin_lock_irqsave(&vga_lock, flags); |
1483 | list_for_each_entry(vgadev, &vga_list, list) { |
1484 | if (vgadev->set_decode) { |
1485 | new_decodes = vgadev->set_decode(vgadev->pdev, |
1486 | new_state); |
1487 | vga_update_device_decodes(vgadev, new_decodes); |
1488 | } |
1489 | } |
1490 | spin_unlock_irqrestore(lock: &vga_lock, flags); |
1491 | } |
1492 | |
1493 | static int pci_notify(struct notifier_block *nb, unsigned long action, |
1494 | void *data) |
1495 | { |
1496 | struct device *dev = data; |
1497 | struct pci_dev *pdev = to_pci_dev(dev); |
1498 | bool notify = false; |
1499 | |
1500 | vgaarb_dbg(dev, "%s\n" , __func__); |
1501 | |
1502 | /* Only deal with VGA class devices */ |
1503 | if (!pci_is_vga(pdev)) |
1504 | return 0; |
1505 | |
1506 | /* |
1507 | * For now, we're only interested in devices added and removed. |
1508 | * I didn't test this thing here, so someone needs to double check |
1509 | * for the cases of hot-pluggable VGA cards. |
1510 | */ |
1511 | if (action == BUS_NOTIFY_ADD_DEVICE) |
1512 | notify = vga_arbiter_add_pci_device(pdev); |
1513 | else if (action == BUS_NOTIFY_DEL_DEVICE) |
1514 | notify = vga_arbiter_del_pci_device(pdev); |
1515 | |
1516 | if (notify) |
1517 | vga_arbiter_notify_clients(); |
1518 | return 0; |
1519 | } |
1520 | |
1521 | static struct notifier_block pci_notifier = { |
1522 | .notifier_call = pci_notify, |
1523 | }; |
1524 | |
1525 | static const struct file_operations vga_arb_device_fops = { |
1526 | .read = vga_arb_read, |
1527 | .write = vga_arb_write, |
1528 | .poll = vga_arb_fpoll, |
1529 | .open = vga_arb_open, |
1530 | .release = vga_arb_release, |
1531 | .llseek = noop_llseek, |
1532 | }; |
1533 | |
1534 | static struct miscdevice vga_arb_device = { |
1535 | MISC_DYNAMIC_MINOR, "vga_arbiter" , &vga_arb_device_fops |
1536 | }; |
1537 | |
1538 | static int __init vga_arb_device_init(void) |
1539 | { |
1540 | int rc; |
1541 | struct pci_dev *pdev; |
1542 | |
1543 | rc = misc_register(misc: &vga_arb_device); |
1544 | if (rc < 0) |
1545 | pr_err("error %d registering device\n" , rc); |
1546 | |
1547 | bus_register_notifier(bus: &pci_bus_type, nb: &pci_notifier); |
1548 | |
1549 | /* Add all VGA class PCI devices by default */ |
1550 | pdev = NULL; |
1551 | while ((pdev = |
1552 | pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, |
1553 | PCI_ANY_ID, from: pdev)) != NULL) { |
1554 | if (pci_is_vga(pdev)) |
1555 | vga_arbiter_add_pci_device(pdev); |
1556 | } |
1557 | |
1558 | pr_info("loaded\n" ); |
1559 | return rc; |
1560 | } |
1561 | subsys_initcall_sync(vga_arb_device_init); |
1562 | |