1 // SPDX-License-Identifier: MIT 2 /* 3 * vgaarb.c: Implements the 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 34 #include <linux/uaccess.h> 35 36 #include <linux/vgaarb.h> 37 38 static void vga_arbiter_notify_clients(void); 39 /* 40 * We keep a list of all vga devices in the system to speed 41 * up the various operations of the arbiter 42 */ 43 struct vga_device { 44 struct list_head list; 45 struct pci_dev *pdev; 46 unsigned int decodes; /* what does it decodes */ 47 unsigned int owns; /* what does it owns */ 48 unsigned int locks; /* what does it locks */ 49 unsigned int io_lock_cnt; /* legacy IO lock count */ 50 unsigned int mem_lock_cnt; /* legacy MEM lock count */ 51 unsigned int io_norm_cnt; /* normal IO count */ 52 unsigned int mem_norm_cnt; /* normal MEM count */ 53 bool bridge_has_one_vga; 54 bool is_firmware_default; /* device selected by firmware */ 55 unsigned int (*set_decode)(struct pci_dev *pdev, bool decode); 56 }; 57 58 static LIST_HEAD(vga_list); 59 static int vga_count, vga_decode_count; 60 static bool vga_arbiter_used; 61 static DEFINE_SPINLOCK(vga_lock); 62 static DECLARE_WAIT_QUEUE_HEAD(vga_wait_queue); 63 64 65 static const char *vga_iostate_to_str(unsigned int iostate) 66 { 67 /* Ignore VGA_RSRC_IO and VGA_RSRC_MEM */ 68 iostate &= VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; 69 switch (iostate) { 70 case VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM: 71 return "io+mem"; 72 case VGA_RSRC_LEGACY_IO: 73 return "io"; 74 case VGA_RSRC_LEGACY_MEM: 75 return "mem"; 76 } 77 return "none"; 78 } 79 80 static int vga_str_to_iostate(char *buf, int str_size, int *io_state) 81 { 82 /* we could in theory hand out locks on IO and mem 83 * separately to userspace but it can cause deadlocks */ 84 if (strncmp(buf, "none", 4) == 0) { 85 *io_state = VGA_RSRC_NONE; 86 return 1; 87 } 88 89 /* XXX We're not chekcing 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 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 120 * is rather dumb and will probably only work properly on single 121 * vga card setups and/or x86 platforms. 122 * 123 * If your VGA default device is not PCI, you'll have to return 124 * NULL here. In this case, I assume it will not conflict with 125 * any PCI card. If this is not true, I'll have to define two archs 126 * hooks for enabling/disabling the VGA default device if that is 127 * possible. This may be a problem with real _ISA_ VGA cards, in 128 * addition to a PCI one. I don't know at this point how to deal 129 * with that card. Can theirs IOs be disabled at all ? If not, then 130 * I suppose it's a matter of having the proper arch hook telling 131 * us about it, so we basically never allow anybody to succeed a 132 * vga_get()... 133 */ 134 struct pci_dev *vga_default_device(void) 135 { 136 return vga_default; 137 } 138 EXPORT_SYMBOL_GPL(vga_default_device); 139 140 void vga_set_default_device(struct pci_dev *pdev) 141 { 142 if (vga_default == pdev) 143 return; 144 145 pci_dev_put(vga_default); 146 vga_default = pci_dev_get(pdev); 147 } 148 149 /** 150 * vga_remove_vgacon - deactivete vga console 151 * 152 * Unbind and unregister vgacon in case pdev is the default vga 153 * device. Can be called by gpu drivers on initialization to make 154 * sure vga register access done by vgacon will not disturb the 155 * device. 156 * 157 * @pdev: pci device. 158 */ 159 #if !defined(CONFIG_VGA_CONSOLE) 160 int vga_remove_vgacon(struct pci_dev *pdev) 161 { 162 return 0; 163 } 164 #elif !defined(CONFIG_DUMMY_CONSOLE) 165 int vga_remove_vgacon(struct pci_dev *pdev) 166 { 167 return -ENODEV; 168 } 169 #else 170 int vga_remove_vgacon(struct pci_dev *pdev) 171 { 172 int ret = 0; 173 174 if (pdev != vga_default) 175 return 0; 176 vgaarb_info(&pdev->dev, "deactivate vga console\n"); 177 178 console_lock(); 179 if (con_is_bound(&vga_con)) 180 ret = do_take_over_console(&dummy_con, 0, 181 MAX_NR_CONSOLES - 1, 1); 182 if (ret == 0) { 183 ret = do_unregister_con_driver(&vga_con); 184 185 /* Ignore "already unregistered". */ 186 if (ret == -ENODEV) 187 ret = 0; 188 } 189 console_unlock(); 190 191 return ret; 192 } 193 #endif 194 EXPORT_SYMBOL(vga_remove_vgacon); 195 196 /* If we don't ever use VGA arb we should avoid 197 turning off anything anywhere due to old X servers getting 198 confused about the boot device not being VGA */ 199 static void vga_check_first_use(void) 200 { 201 /* we should inform all GPUs in the system that 202 * VGA arb has occurred and to try and disable resources 203 * if they can */ 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 /* Account for "normal" resources to lock. If we decode the legacy, 220 * counterpart, we need to request it as well 221 */ 222 if ((rsrc & VGA_RSRC_NORMAL_IO) && 223 (vgadev->decodes & VGA_RSRC_LEGACY_IO)) 224 rsrc |= VGA_RSRC_LEGACY_IO; 225 if ((rsrc & VGA_RSRC_NORMAL_MEM) && 226 (vgadev->decodes & VGA_RSRC_LEGACY_MEM)) 227 rsrc |= VGA_RSRC_LEGACY_MEM; 228 229 vgaarb_dbg(dev, "%s: %d\n", __func__, rsrc); 230 vgaarb_dbg(dev, "%s: owns: %d\n", __func__, vgadev->owns); 231 232 /* Check what resources we need to acquire */ 233 wants = rsrc & ~vgadev->owns; 234 235 /* We already own everything, just mark locked & bye bye */ 236 if (wants == 0) 237 goto lock_them; 238 239 /* We don't need to request a legacy resource, we just enable 240 * appropriate decoding and go 241 */ 242 legacy_wants = wants & VGA_RSRC_LEGACY_MASK; 243 if (legacy_wants == 0) 244 goto enable_them; 245 246 /* Ok, we don't, let's find out how we need to kick off */ 247 list_for_each_entry(conflict, &vga_list, list) { 248 unsigned int lwants = legacy_wants; 249 unsigned int change_bridge = 0; 250 251 /* Don't conflict with myself */ 252 if (vgadev == conflict) 253 continue; 254 255 /* We have a possible conflict. before we go further, we must 256 * check if we sit on the same bus as the conflicting device. 257 * if we don't, then we must tie both IO and MEM resources 258 * together since there is only a single bit controlling 259 * VGA forwarding on P2P bridges 260 */ 261 if (vgadev->pdev->bus != conflict->pdev->bus) { 262 change_bridge = 1; 263 lwants = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; 264 } 265 266 /* Check if the guy has a lock on the resource. If he does, 267 * return the conflicting entry 268 */ 269 if (conflict->locks & lwants) 270 return conflict; 271 272 /* Ok, now check if it owns the resource we want. We can 273 * lock resources that are not decoded, therefore a device 274 * can own resources it doesn't decode. 275 */ 276 match = lwants & conflict->owns; 277 if (!match) 278 continue; 279 280 /* looks like he doesn't have a lock, we can steal 281 * them from him 282 */ 283 284 flags = 0; 285 pci_bits = 0; 286 287 /* If we can't control legacy resources via the bridge, we 288 * also need to disable normal decoding. 289 */ 290 if (!conflict->bridge_has_one_vga) { 291 if ((match & conflict->decodes) & VGA_RSRC_LEGACY_MEM) 292 pci_bits |= PCI_COMMAND_MEMORY; 293 if ((match & conflict->decodes) & VGA_RSRC_LEGACY_IO) 294 pci_bits |= PCI_COMMAND_IO; 295 296 if (pci_bits) 297 flags |= PCI_VGA_STATE_CHANGE_DECODES; 298 } 299 300 if (change_bridge) 301 flags |= PCI_VGA_STATE_CHANGE_BRIDGE; 302 303 pci_set_vga_state(conflict->pdev, false, pci_bits, flags); 304 conflict->owns &= ~match; 305 306 /* If we disabled normal decoding, reflect it in owns */ 307 if (pci_bits & PCI_COMMAND_MEMORY) 308 conflict->owns &= ~VGA_RSRC_NORMAL_MEM; 309 if (pci_bits & PCI_COMMAND_IO) 310 conflict->owns &= ~VGA_RSRC_NORMAL_IO; 311 } 312 313 enable_them: 314 /* ok dude, we got it, everybody conflicting has been disabled, let's 315 * enable us. Mark any bits in "owns" regardless of whether we 316 * decoded them. We can lock resources we don't decode, therefore 317 * we must track them via "owns". 318 */ 319 flags = 0; 320 pci_bits = 0; 321 322 if (!vgadev->bridge_has_one_vga) { 323 flags |= PCI_VGA_STATE_CHANGE_DECODES; 324 if (wants & (VGA_RSRC_LEGACY_MEM|VGA_RSRC_NORMAL_MEM)) 325 pci_bits |= PCI_COMMAND_MEMORY; 326 if (wants & (VGA_RSRC_LEGACY_IO|VGA_RSRC_NORMAL_IO)) 327 pci_bits |= PCI_COMMAND_IO; 328 } 329 if (wants & VGA_RSRC_LEGACY_MASK) 330 flags |= PCI_VGA_STATE_CHANGE_BRIDGE; 331 332 pci_set_vga_state(vgadev->pdev, true, pci_bits, flags); 333 334 vgadev->owns |= wants; 335 lock_them: 336 vgadev->locks |= (rsrc & VGA_RSRC_LEGACY_MASK); 337 if (rsrc & VGA_RSRC_LEGACY_IO) 338 vgadev->io_lock_cnt++; 339 if (rsrc & VGA_RSRC_LEGACY_MEM) 340 vgadev->mem_lock_cnt++; 341 if (rsrc & VGA_RSRC_NORMAL_IO) 342 vgadev->io_norm_cnt++; 343 if (rsrc & VGA_RSRC_NORMAL_MEM) 344 vgadev->mem_norm_cnt++; 345 346 return NULL; 347 } 348 349 static void __vga_put(struct vga_device *vgadev, unsigned int rsrc) 350 { 351 struct device *dev = &vgadev->pdev->dev; 352 unsigned int old_locks = vgadev->locks; 353 354 vgaarb_dbg(dev, "%s\n", __func__); 355 356 /* Update our counters, and account for equivalent legacy resources 357 * if we decode them 358 */ 359 if ((rsrc & VGA_RSRC_NORMAL_IO) && vgadev->io_norm_cnt > 0) { 360 vgadev->io_norm_cnt--; 361 if (vgadev->decodes & VGA_RSRC_LEGACY_IO) 362 rsrc |= VGA_RSRC_LEGACY_IO; 363 } 364 if ((rsrc & VGA_RSRC_NORMAL_MEM) && vgadev->mem_norm_cnt > 0) { 365 vgadev->mem_norm_cnt--; 366 if (vgadev->decodes & VGA_RSRC_LEGACY_MEM) 367 rsrc |= VGA_RSRC_LEGACY_MEM; 368 } 369 if ((rsrc & VGA_RSRC_LEGACY_IO) && vgadev->io_lock_cnt > 0) 370 vgadev->io_lock_cnt--; 371 if ((rsrc & VGA_RSRC_LEGACY_MEM) && vgadev->mem_lock_cnt > 0) 372 vgadev->mem_lock_cnt--; 373 374 /* Just clear lock bits, we do lazy operations so we don't really 375 * have to bother about anything else at this point 376 */ 377 if (vgadev->io_lock_cnt == 0) 378 vgadev->locks &= ~VGA_RSRC_LEGACY_IO; 379 if (vgadev->mem_lock_cnt == 0) 380 vgadev->locks &= ~VGA_RSRC_LEGACY_MEM; 381 382 /* Kick the wait queue in case somebody was waiting if we actually 383 * released something 384 */ 385 if (old_locks != vgadev->locks) 386 wake_up_all(&vga_wait_queue); 387 } 388 389 /** 390 * vga_get - acquire & locks VGA resources 391 * @pdev: pci device of the VGA card or NULL for the system default 392 * @rsrc: bit mask of resources to acquire and lock 393 * @interruptible: blocking should be interruptible by signals ? 394 * 395 * This function acquires VGA resources for the given card and mark those 396 * resources locked. If the resource requested are "normal" (and not legacy) 397 * resources, the arbiter will first check whether the card is doing legacy 398 * decoding for that type of resource. If yes, the lock is "converted" into a 399 * legacy resource lock. 400 * 401 * The arbiter will first look for all VGA cards that might conflict and disable 402 * their IOs and/or Memory access, including VGA forwarding on P2P bridges if 403 * necessary, so that the requested resources can be used. Then, the card is 404 * marked as locking these resources and the IO and/or Memory accesses are 405 * enabled on the card (including VGA forwarding on parent P2P bridges if any). 406 * 407 * This function will block if some conflicting card is already locking one of 408 * the required resources (or any resource on a different bus segment, since P2P 409 * bridges don't differentiate VGA memory and IO afaik). You can indicate 410 * whether this blocking should be interruptible by a signal (for userland 411 * interface) or not. 412 * 413 * Must not be called at interrupt time or in atomic context. If the card 414 * already owns the resources, the function succeeds. Nested calls are 415 * supported (a per-resource counter is maintained) 416 * 417 * On success, release the VGA resource again with vga_put(). 418 * 419 * Returns: 420 * 421 * 0 on success, negative error code on failure. 422 */ 423 int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible) 424 { 425 struct vga_device *vgadev, *conflict; 426 unsigned long flags; 427 wait_queue_entry_t wait; 428 int rc = 0; 429 430 vga_check_first_use(); 431 /* The one who calls us should check for this, but lets be sure... */ 432 if (pdev == NULL) 433 pdev = vga_default_device(); 434 if (pdev == NULL) 435 return 0; 436 437 for (;;) { 438 spin_lock_irqsave(&vga_lock, flags); 439 vgadev = vgadev_find(pdev); 440 if (vgadev == NULL) { 441 spin_unlock_irqrestore(&vga_lock, flags); 442 rc = -ENODEV; 443 break; 444 } 445 conflict = __vga_tryget(vgadev, rsrc); 446 spin_unlock_irqrestore(&vga_lock, flags); 447 if (conflict == NULL) 448 break; 449 450 451 /* We have a conflict, we wait until somebody kicks the 452 * work queue. Currently we have one work queue that we 453 * kick each time some resources are released, but it would 454 * be fairly easy to have a per device one so that we only 455 * need to attach to the conflicting device 456 */ 457 init_waitqueue_entry(&wait, current); 458 add_wait_queue(&vga_wait_queue, &wait); 459 set_current_state(interruptible ? 460 TASK_INTERRUPTIBLE : 461 TASK_UNINTERRUPTIBLE); 462 if (interruptible && signal_pending(current)) { 463 __set_current_state(TASK_RUNNING); 464 remove_wait_queue(&vga_wait_queue, &wait); 465 rc = -ERESTARTSYS; 466 break; 467 } 468 schedule(); 469 remove_wait_queue(&vga_wait_queue, &wait); 470 } 471 return rc; 472 } 473 EXPORT_SYMBOL(vga_get); 474 475 /** 476 * vga_tryget - try to acquire & lock legacy VGA resources 477 * @pdev: pci devivce of VGA card or NULL for system default 478 * @rsrc: bit mask of resources to acquire and lock 479 * 480 * This function performs the same operation as vga_get(), but will return an 481 * error (-EBUSY) instead of blocking if the resources are already locked by 482 * another card. It can be called in any context 483 * 484 * On success, release the VGA resource again with vga_put(). 485 * 486 * Returns: 487 * 488 * 0 on success, negative error code on failure. 489 */ 490 static int vga_tryget(struct pci_dev *pdev, unsigned int rsrc) 491 { 492 struct vga_device *vgadev; 493 unsigned long flags; 494 int rc = 0; 495 496 vga_check_first_use(); 497 498 /* The one who calls us should check for this, but lets be sure... */ 499 if (pdev == NULL) 500 pdev = vga_default_device(); 501 if (pdev == NULL) 502 return 0; 503 spin_lock_irqsave(&vga_lock, flags); 504 vgadev = vgadev_find(pdev); 505 if (vgadev == NULL) { 506 rc = -ENODEV; 507 goto bail; 508 } 509 if (__vga_tryget(vgadev, rsrc)) 510 rc = -EBUSY; 511 bail: 512 spin_unlock_irqrestore(&vga_lock, flags); 513 return rc; 514 } 515 516 /** 517 * vga_put - release lock on legacy VGA resources 518 * @pdev: pci device of VGA card or NULL for system default 519 * @rsrc: but mask of resource to release 520 * 521 * This fuction releases resources previously locked by vga_get() or 522 * vga_tryget(). The resources aren't disabled right away, so that a subsequence 523 * vga_get() on the same card will succeed immediately. Resources have a 524 * counter, so locks are only released if the counter reaches 0. 525 */ 526 void vga_put(struct pci_dev *pdev, unsigned int rsrc) 527 { 528 struct vga_device *vgadev; 529 unsigned long flags; 530 531 /* The one who calls us should check for this, but lets be sure... */ 532 if (pdev == NULL) 533 pdev = vga_default_device(); 534 if (pdev == NULL) 535 return; 536 spin_lock_irqsave(&vga_lock, flags); 537 vgadev = vgadev_find(pdev); 538 if (vgadev == NULL) 539 goto bail; 540 __vga_put(vgadev, rsrc); 541 bail: 542 spin_unlock_irqrestore(&vga_lock, flags); 543 } 544 EXPORT_SYMBOL(vga_put); 545 546 static bool vga_is_firmware_default(struct pci_dev *pdev) 547 { 548 #if defined(CONFIG_X86) || defined(CONFIG_IA64) 549 u64 base = screen_info.lfb_base; 550 u64 size = screen_info.lfb_size; 551 struct resource *r; 552 u64 limit; 553 554 /* Select the device owning the boot framebuffer if there is one */ 555 556 if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) 557 base |= (u64)screen_info.ext_lfb_base << 32; 558 559 limit = base + size; 560 561 /* Does firmware framebuffer belong to us? */ 562 pci_dev_for_each_resource(pdev, r) { 563 if (resource_type(r) != IORESOURCE_MEM) 564 continue; 565 566 if (!r->start || !r->end) 567 continue; 568 569 if (base < r->start || limit >= r->end) 570 continue; 571 572 return true; 573 } 574 #endif 575 return false; 576 } 577 578 static bool vga_arb_integrated_gpu(struct device *dev) 579 { 580 #if defined(CONFIG_ACPI) 581 struct acpi_device *adev = ACPI_COMPANION(dev); 582 583 return adev && !strcmp(acpi_device_hid(adev), ACPI_VIDEO_HID); 584 #else 585 return false; 586 #endif 587 } 588 589 /* 590 * Return true if vgadev is a better default VGA device than the best one 591 * we've seen so far. 592 */ 593 static bool vga_is_boot_device(struct vga_device *vgadev) 594 { 595 struct vga_device *boot_vga = vgadev_find(vga_default_device()); 596 struct pci_dev *pdev = vgadev->pdev; 597 u16 cmd, boot_cmd; 598 599 /* 600 * We select the default VGA device in this order: 601 * Firmware framebuffer (see vga_arb_select_default_device()) 602 * Legacy VGA device (owns VGA_RSRC_LEGACY_MASK) 603 * Non-legacy integrated device (see vga_arb_select_default_device()) 604 * Non-legacy discrete device (see vga_arb_select_default_device()) 605 * Other device (see vga_arb_select_default_device()) 606 */ 607 608 /* 609 * We always prefer a firmware default device, so if we've already 610 * found one, there's no need to consider vgadev. 611 */ 612 if (boot_vga && boot_vga->is_firmware_default) 613 return false; 614 615 if (vga_is_firmware_default(pdev)) { 616 vgadev->is_firmware_default = true; 617 return true; 618 } 619 620 /* 621 * A legacy VGA device has MEM and IO enabled and any bridges 622 * leading to it have PCI_BRIDGE_CTL_VGA enabled so the legacy 623 * resources ([mem 0xa0000-0xbffff], [io 0x3b0-0x3bb], etc) are 624 * routed to it. 625 * 626 * We use the first one we find, so if we've already found one, 627 * vgadev is no better. 628 */ 629 if (boot_vga && 630 (boot_vga->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK) 631 return false; 632 633 if ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK) 634 return true; 635 636 /* 637 * If we haven't found a legacy VGA device, accept a non-legacy 638 * device. It may have either IO or MEM enabled, and bridges may 639 * not have PCI_BRIDGE_CTL_VGA enabled, so it may not be able to 640 * use legacy VGA resources. Prefer an integrated GPU over others. 641 */ 642 pci_read_config_word(pdev, PCI_COMMAND, &cmd); 643 if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) { 644 645 /* 646 * An integrated GPU overrides a previous non-legacy 647 * device. We expect only a single integrated GPU, but if 648 * there are more, we use the *last* because that was the 649 * previous behavior. 650 */ 651 if (vga_arb_integrated_gpu(&pdev->dev)) 652 return true; 653 654 /* 655 * We prefer the first non-legacy discrete device we find. 656 * If we already found one, vgadev is no better. 657 */ 658 if (boot_vga) { 659 pci_read_config_word(boot_vga->pdev, PCI_COMMAND, 660 &boot_cmd); 661 if (boot_cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) 662 return false; 663 } 664 return true; 665 } 666 667 /* 668 * vgadev has neither IO nor MEM enabled. If we haven't found any 669 * other VGA devices, it is the best candidate so far. 670 */ 671 if (!boot_vga) 672 return true; 673 674 return false; 675 } 676 677 /* 678 * Rules for using a bridge to control a VGA descendant decoding: if a bridge 679 * has only one VGA descendant then it can be used to control the VGA routing 680 * for that device. It should always use the bridge closest to the device to 681 * control it. If a bridge has a direct VGA descendant, but also have a sub- 682 * bridge VGA descendant then we cannot use that bridge to control the direct 683 * VGA descendant. So for every device we register, we need to iterate all 684 * its parent bridges so we can invalidate any devices using them properly. 685 */ 686 static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev) 687 { 688 struct vga_device *same_bridge_vgadev; 689 struct pci_bus *new_bus, *bus; 690 struct pci_dev *new_bridge, *bridge; 691 692 vgadev->bridge_has_one_vga = true; 693 694 if (list_empty(&vga_list)) { 695 vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n"); 696 return; 697 } 698 699 /* okay iterate the new devices bridge hierarachy */ 700 new_bus = vgadev->pdev->bus; 701 while (new_bus) { 702 new_bridge = new_bus->self; 703 704 /* go through list of devices already registered */ 705 list_for_each_entry(same_bridge_vgadev, &vga_list, list) { 706 bus = same_bridge_vgadev->pdev->bus; 707 bridge = bus->self; 708 709 /* see if the share a bridge with this device */ 710 if (new_bridge == bridge) { 711 /* 712 * If their direct parent bridge is the same 713 * as any bridge of this device then it can't 714 * be used for that device. 715 */ 716 same_bridge_vgadev->bridge_has_one_vga = false; 717 } 718 719 /* 720 * Now iterate the previous devices bridge hierarchy. 721 * If the new devices parent bridge is in the other 722 * devices hierarchy then we can't use it to control 723 * this device 724 */ 725 while (bus) { 726 bridge = bus->self; 727 728 if (bridge && bridge == vgadev->pdev->bus->self) 729 vgadev->bridge_has_one_vga = false; 730 731 bus = bus->parent; 732 } 733 } 734 new_bus = new_bus->parent; 735 } 736 737 if (vgadev->bridge_has_one_vga) 738 vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n"); 739 else 740 vgaarb_info(&vgadev->pdev->dev, "no bridge control possible\n"); 741 } 742 743 /* 744 * Currently, we assume that the "initial" setup of the system is 745 * not sane, that is we come up with conflicting devices and let 746 * the arbiter's client decides if devices decodes or not legacy 747 * things. 748 */ 749 static bool vga_arbiter_add_pci_device(struct pci_dev *pdev) 750 { 751 struct vga_device *vgadev; 752 unsigned long flags; 753 struct pci_bus *bus; 754 struct pci_dev *bridge; 755 u16 cmd; 756 757 /* Only deal with VGA class devices */ 758 if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA) 759 return false; 760 761 /* Allocate structure */ 762 vgadev = kzalloc(sizeof(struct vga_device), GFP_KERNEL); 763 if (vgadev == NULL) { 764 vgaarb_err(&pdev->dev, "failed to allocate VGA arbiter data\n"); 765 /* 766 * What to do on allocation failure ? For now, let's just do 767 * nothing, I'm not sure there is anything saner to be done. 768 */ 769 return false; 770 } 771 772 /* Take lock & check for duplicates */ 773 spin_lock_irqsave(&vga_lock, flags); 774 if (vgadev_find(pdev) != NULL) { 775 BUG_ON(1); 776 goto fail; 777 } 778 vgadev->pdev = pdev; 779 780 /* By default, assume we decode everything */ 781 vgadev->decodes = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM | 782 VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM; 783 784 /* by default mark it as decoding */ 785 vga_decode_count++; 786 /* Mark that we "own" resources based on our enables, we will 787 * clear that below if the bridge isn't forwarding 788 */ 789 pci_read_config_word(pdev, PCI_COMMAND, &cmd); 790 if (cmd & PCI_COMMAND_IO) 791 vgadev->owns |= VGA_RSRC_LEGACY_IO; 792 if (cmd & PCI_COMMAND_MEMORY) 793 vgadev->owns |= VGA_RSRC_LEGACY_MEM; 794 795 /* Check if VGA cycles can get down to us */ 796 bus = pdev->bus; 797 while (bus) { 798 bridge = bus->self; 799 if (bridge) { 800 u16 l; 801 802 pci_read_config_word(bridge, PCI_BRIDGE_CONTROL, &l); 803 if (!(l & PCI_BRIDGE_CTL_VGA)) { 804 vgadev->owns = 0; 805 break; 806 } 807 } 808 bus = bus->parent; 809 } 810 811 if (vga_is_boot_device(vgadev)) { 812 vgaarb_info(&pdev->dev, "setting as boot VGA device%s\n", 813 vga_default_device() ? 814 " (overriding previous)" : ""); 815 vga_set_default_device(pdev); 816 } 817 818 vga_arbiter_check_bridge_sharing(vgadev); 819 820 /* Add to the list */ 821 list_add_tail(&vgadev->list, &vga_list); 822 vga_count++; 823 vgaarb_info(&pdev->dev, "VGA device added: decodes=%s,owns=%s,locks=%s\n", 824 vga_iostate_to_str(vgadev->decodes), 825 vga_iostate_to_str(vgadev->owns), 826 vga_iostate_to_str(vgadev->locks)); 827 828 spin_unlock_irqrestore(&vga_lock, flags); 829 return true; 830 fail: 831 spin_unlock_irqrestore(&vga_lock, flags); 832 kfree(vgadev); 833 return false; 834 } 835 836 static bool vga_arbiter_del_pci_device(struct pci_dev *pdev) 837 { 838 struct vga_device *vgadev; 839 unsigned long flags; 840 bool ret = true; 841 842 spin_lock_irqsave(&vga_lock, flags); 843 vgadev = vgadev_find(pdev); 844 if (vgadev == NULL) { 845 ret = false; 846 goto bail; 847 } 848 849 if (vga_default == pdev) 850 vga_set_default_device(NULL); 851 852 if (vgadev->decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM)) 853 vga_decode_count--; 854 855 /* Remove entry from list */ 856 list_del(&vgadev->list); 857 vga_count--; 858 859 /* Wake up all possible waiters */ 860 wake_up_all(&vga_wait_queue); 861 bail: 862 spin_unlock_irqrestore(&vga_lock, flags); 863 kfree(vgadev); 864 return ret; 865 } 866 867 /* this is called with the lock */ 868 static inline void vga_update_device_decodes(struct vga_device *vgadev, 869 int new_decodes) 870 { 871 struct device *dev = &vgadev->pdev->dev; 872 int old_decodes, decodes_removed, decodes_unlocked; 873 874 old_decodes = vgadev->decodes; 875 decodes_removed = ~new_decodes & old_decodes; 876 decodes_unlocked = vgadev->locks & decodes_removed; 877 vgadev->decodes = new_decodes; 878 879 vgaarb_info(dev, "changed VGA decodes: olddecodes=%s,decodes=%s:owns=%s\n", 880 vga_iostate_to_str(old_decodes), 881 vga_iostate_to_str(vgadev->decodes), 882 vga_iostate_to_str(vgadev->owns)); 883 884 /* if we removed locked decodes, lock count goes to zero, and release */ 885 if (decodes_unlocked) { 886 if (decodes_unlocked & VGA_RSRC_LEGACY_IO) 887 vgadev->io_lock_cnt = 0; 888 if (decodes_unlocked & VGA_RSRC_LEGACY_MEM) 889 vgadev->mem_lock_cnt = 0; 890 __vga_put(vgadev, decodes_unlocked); 891 } 892 893 /* change decodes counter */ 894 if (old_decodes & VGA_RSRC_LEGACY_MASK && 895 !(new_decodes & VGA_RSRC_LEGACY_MASK)) 896 vga_decode_count--; 897 if (!(old_decodes & VGA_RSRC_LEGACY_MASK) && 898 new_decodes & VGA_RSRC_LEGACY_MASK) 899 vga_decode_count++; 900 vgaarb_dbg(dev, "decoding count now is: %d\n", vga_decode_count); 901 } 902 903 static void __vga_set_legacy_decoding(struct pci_dev *pdev, 904 unsigned int decodes, 905 bool userspace) 906 { 907 struct vga_device *vgadev; 908 unsigned long flags; 909 910 decodes &= VGA_RSRC_LEGACY_MASK; 911 912 spin_lock_irqsave(&vga_lock, flags); 913 vgadev = vgadev_find(pdev); 914 if (vgadev == NULL) 915 goto bail; 916 917 /* don't let userspace futz with kernel driver decodes */ 918 if (userspace && vgadev->set_decode) 919 goto bail; 920 921 /* update the device decodes + counter */ 922 vga_update_device_decodes(vgadev, decodes); 923 924 /* XXX if somebody is going from "doesn't decode" to "decodes" state 925 * here, additional care must be taken as we may have pending owner 926 * ship of non-legacy region ... 927 */ 928 bail: 929 spin_unlock_irqrestore(&vga_lock, flags); 930 } 931 932 /** 933 * vga_set_legacy_decoding 934 * @pdev: pci device of the VGA card 935 * @decodes: bit mask of what legacy regions the card decodes 936 * 937 * Indicates to the arbiter if the card decodes legacy VGA IOs, legacy VGA 938 * Memory, both, or none. All cards default to both, the card driver (fbdev for 939 * example) should tell the arbiter if it has disabled legacy decoding, so the 940 * card can be left out of the arbitration process (and can be safe to take 941 * interrupts at any time. 942 */ 943 void vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes) 944 { 945 __vga_set_legacy_decoding(pdev, decodes, false); 946 } 947 EXPORT_SYMBOL(vga_set_legacy_decoding); 948 949 /** 950 * vga_client_register - register or unregister a VGA arbitration client 951 * @pdev: pci device of the VGA client 952 * @set_decode: vga decode change callback 953 * 954 * Clients have two callback mechanisms they can use. 955 * 956 * @set_decode callback: If a client can disable its GPU VGA resource, it 957 * will get a callback from this to set the encode/decode state. 958 * 959 * Rationale: we cannot disable VGA decode resources unconditionally some single 960 * GPU laptops seem to require ACPI or BIOS access to the VGA registers to 961 * control things like backlights etc. Hopefully newer multi-GPU laptops do 962 * something saner, and desktops won't have any special ACPI for this. The 963 * driver will get a callback when VGA arbitration is first used by userspace 964 * since some older X servers have issues. 965 * 966 * This function does not check whether a client for @pdev has been registered 967 * already. 968 * 969 * To unregister just call vga_client_unregister(). 970 * 971 * Returns: 0 on success, -1 on failure 972 */ 973 int vga_client_register(struct pci_dev *pdev, 974 unsigned int (*set_decode)(struct pci_dev *pdev, bool decode)) 975 { 976 int ret = -ENODEV; 977 struct vga_device *vgadev; 978 unsigned long flags; 979 980 spin_lock_irqsave(&vga_lock, flags); 981 vgadev = vgadev_find(pdev); 982 if (!vgadev) 983 goto bail; 984 985 vgadev->set_decode = set_decode; 986 ret = 0; 987 988 bail: 989 spin_unlock_irqrestore(&vga_lock, flags); 990 return ret; 991 992 } 993 EXPORT_SYMBOL(vga_client_register); 994 995 /* 996 * Char driver implementation 997 * 998 * Semantics is: 999 * 1000 * open : open user instance of the arbitrer. by default, it's 1001 * attached to the default VGA device of the system. 1002 * 1003 * close : close user instance, release locks 1004 * 1005 * read : return a string indicating the status of the target. 1006 * an IO state string is of the form {io,mem,io+mem,none}, 1007 * mc and ic are respectively mem and io lock counts (for 1008 * debugging/diagnostic only). "decodes" indicate what the 1009 * card currently decodes, "owns" indicates what is currently 1010 * enabled on it, and "locks" indicates what is locked by this 1011 * card. If the card is unplugged, we get "invalid" then for 1012 * card_ID and an -ENODEV error is returned for any command 1013 * until a new card is targeted 1014 * 1015 * "<card_ID>,decodes=<io_state>,owns=<io_state>,locks=<io_state> (ic,mc)" 1016 * 1017 * write : write a command to the arbiter. List of commands is: 1018 * 1019 * target <card_ID> : switch target to card <card_ID> (see below) 1020 * lock <io_state> : acquires locks on target ("none" is invalid io_state) 1021 * trylock <io_state> : non-blocking acquire locks on target 1022 * unlock <io_state> : release locks on target 1023 * unlock all : release all locks on target held by this user 1024 * decodes <io_state> : set the legacy decoding attributes for the card 1025 * 1026 * poll : event if something change on any card (not just the target) 1027 * 1028 * card_ID is of the form "PCI:domain:bus:dev.fn". It can be set to "default" 1029 * to go back to the system default card (TODO: not implemented yet). 1030 * Currently, only PCI is supported as a prefix, but the userland API may 1031 * support other bus types in the future, even if the current kernel 1032 * implementation doesn't. 1033 * 1034 * Note about locks: 1035 * 1036 * The driver keeps track of which user has what locks on which card. It 1037 * supports stacking, like the kernel one. This complexifies the implementation 1038 * a bit, but makes the arbiter more tolerant to userspace problems and able 1039 * to properly cleanup in all cases when a process dies. 1040 * Currently, a max of 16 cards simultaneously can have locks issued from 1041 * userspace for a given user (file descriptor instance) of the arbiter. 1042 * 1043 * If the device is hot-unplugged, there is a hook inside the module to notify 1044 * they being added/removed in the system and automatically added/removed in 1045 * the arbiter. 1046 */ 1047 1048 #define MAX_USER_CARDS CONFIG_VGA_ARB_MAX_GPUS 1049 #define PCI_INVALID_CARD ((struct pci_dev *)-1UL) 1050 1051 /* 1052 * Each user has an array of these, tracking which cards have locks 1053 */ 1054 struct vga_arb_user_card { 1055 struct pci_dev *pdev; 1056 unsigned int mem_cnt; 1057 unsigned int io_cnt; 1058 }; 1059 1060 struct vga_arb_private { 1061 struct list_head list; 1062 struct pci_dev *target; 1063 struct vga_arb_user_card cards[MAX_USER_CARDS]; 1064 spinlock_t lock; 1065 }; 1066 1067 static LIST_HEAD(vga_user_list); 1068 static DEFINE_SPINLOCK(vga_user_lock); 1069 1070 1071 /* 1072 * This function gets a string in the format: "PCI:domain:bus:dev.fn" and 1073 * returns the respective values. If the string is not in this format, 1074 * it returns 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 1083 n = sscanf(buf, "PCI:%x:%x:%x.%x", domain, bus, &slot, &func); 1084 if (n != 4) 1085 return 0; 1086 1087 *devfn = PCI_DEVFN(slot, func); 1088 1089 return 1; 1090 } 1091 1092 static ssize_t vga_arb_read(struct file *file, char __user *buf, 1093 size_t count, loff_t *ppos) 1094 { 1095 struct vga_arb_private *priv = file->private_data; 1096 struct vga_device *vgadev; 1097 struct pci_dev *pdev; 1098 unsigned long flags; 1099 size_t len; 1100 int rc; 1101 char *lbuf; 1102 1103 lbuf = kmalloc(1024, GFP_KERNEL); 1104 if (lbuf == NULL) 1105 return -ENOMEM; 1106 1107 /* Protects vga_list */ 1108 spin_lock_irqsave(&vga_lock, flags); 1109 1110 /* If we are targeting the default, use it */ 1111 pdev = priv->target; 1112 if (pdev == NULL || pdev == PCI_INVALID_CARD) { 1113 spin_unlock_irqrestore(&vga_lock, flags); 1114 len = sprintf(lbuf, "invalid"); 1115 goto done; 1116 } 1117 1118 /* Find card vgadev structure */ 1119 vgadev = vgadev_find(pdev); 1120 if (vgadev == NULL) { 1121 /* Wow, it's not in the list, that shouldn't happen, 1122 * let's fix us up and return invalid card 1123 */ 1124 spin_unlock_irqrestore(&vga_lock, flags); 1125 len = sprintf(lbuf, "invalid"); 1126 goto done; 1127 } 1128 1129 /* Fill the buffer with infos */ 1130 len = snprintf(lbuf, 1024, 1131 "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(vgadev->decodes), 1134 vga_iostate_to_str(vgadev->owns), 1135 vga_iostate_to_str(vgadev->locks), 1136 vgadev->io_lock_cnt, vgadev->mem_lock_cnt); 1137 1138 spin_unlock_irqrestore(&vga_lock, flags); 1139 done: 1140 1141 /* Copy that to user */ 1142 if (len > count) 1143 len = count; 1144 rc = copy_to_user(buf, lbuf, len); 1145 kfree(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(kbuf, buf, count)) 1173 return -EFAULT; 1174 curr_pos = kbuf; 1175 kbuf[count] = '\0'; /* Just to make sure... */ 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(curr_pos, remaining, &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, 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 (curr_pos, remaining, &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(curr_pos, remaining, &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, 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(vga_default_device()); 1320 else { 1321 if (!vga_pci_str_to_vars(curr_pos, remaining, 1322 &domain, &bus, &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(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(pdev); 1367 /* XXX: which value to return? */ 1368 ret_val = -ENOMEM; 1369 goto done; 1370 } 1371 1372 ret_val = count; 1373 pci_dev_put(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(curr_pos, remaining, &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, io_state, 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(file, &vga_wait_queue, 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(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(&priv->list, &vga_user_list); 1426 spin_unlock_irqrestore(&vga_user_lock, flags); 1427 1428 /* Set the client' 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 1435 return 0; 1436 } 1437 1438 static int vga_arb_release(struct inode *inode, struct file *file) 1439 { 1440 struct vga_arb_private *priv = file->private_data; 1441 struct vga_arb_user_card *uc; 1442 unsigned long flags; 1443 int i; 1444 1445 pr_debug("%s\n", __func__); 1446 1447 spin_lock_irqsave(&vga_user_lock, flags); 1448 list_del(&priv->list); 1449 for (i = 0; i < MAX_USER_CARDS; i++) { 1450 uc = &priv->cards[i]; 1451 if (uc->pdev == NULL) 1452 continue; 1453 vgaarb_dbg(&uc->pdev->dev, "uc->io_cnt == %d, uc->mem_cnt == %d\n", 1454 uc->io_cnt, uc->mem_cnt); 1455 while (uc->io_cnt--) 1456 vga_put(uc->pdev, VGA_RSRC_LEGACY_IO); 1457 while (uc->mem_cnt--) 1458 vga_put(uc->pdev, VGA_RSRC_LEGACY_MEM); 1459 } 1460 spin_unlock_irqrestore(&vga_user_lock, flags); 1461 1462 kfree(priv); 1463 1464 return 0; 1465 } 1466 1467 /* 1468 * callback any registered clients to let them know we have a 1469 * change in VGA cards 1470 */ 1471 static void vga_arbiter_notify_clients(void) 1472 { 1473 struct vga_device *vgadev; 1474 unsigned long flags; 1475 uint32_t new_decodes; 1476 bool new_state; 1477 1478 if (!vga_arbiter_used) 1479 return; 1480 1481 spin_lock_irqsave(&vga_lock, flags); 1482 list_for_each_entry(vgadev, &vga_list, list) { 1483 if (vga_count > 1) 1484 new_state = false; 1485 else 1486 new_state = true; 1487 if (vgadev->set_decode) { 1488 new_decodes = vgadev->set_decode(vgadev->pdev, 1489 new_state); 1490 vga_update_device_decodes(vgadev, new_decodes); 1491 } 1492 } 1493 spin_unlock_irqrestore(&vga_lock, flags); 1494 } 1495 1496 static int pci_notify(struct notifier_block *nb, unsigned long action, 1497 void *data) 1498 { 1499 struct device *dev = data; 1500 struct pci_dev *pdev = to_pci_dev(dev); 1501 bool notify = false; 1502 1503 vgaarb_dbg(dev, "%s\n", __func__); 1504 1505 /* For now we're only intereted in devices added and removed. I didn't 1506 * test this thing here, so someone needs to double check for the 1507 * cases of hotplugable vga cards. */ 1508 if (action == BUS_NOTIFY_ADD_DEVICE) 1509 notify = vga_arbiter_add_pci_device(pdev); 1510 else if (action == BUS_NOTIFY_DEL_DEVICE) 1511 notify = vga_arbiter_del_pci_device(pdev); 1512 1513 if (notify) 1514 vga_arbiter_notify_clients(); 1515 return 0; 1516 } 1517 1518 static struct notifier_block pci_notifier = { 1519 .notifier_call = pci_notify, 1520 }; 1521 1522 static const struct file_operations vga_arb_device_fops = { 1523 .read = vga_arb_read, 1524 .write = vga_arb_write, 1525 .poll = vga_arb_fpoll, 1526 .open = vga_arb_open, 1527 .release = vga_arb_release, 1528 .llseek = noop_llseek, 1529 }; 1530 1531 static struct miscdevice vga_arb_device = { 1532 MISC_DYNAMIC_MINOR, "vga_arbiter", &vga_arb_device_fops 1533 }; 1534 1535 static int __init vga_arb_device_init(void) 1536 { 1537 int rc; 1538 struct pci_dev *pdev; 1539 1540 rc = misc_register(&vga_arb_device); 1541 if (rc < 0) 1542 pr_err("error %d registering device\n", rc); 1543 1544 bus_register_notifier(&pci_bus_type, &pci_notifier); 1545 1546 /* We add all PCI devices satisfying VGA class in the arbiter by 1547 * default */ 1548 pdev = NULL; 1549 while ((pdev = 1550 pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, 1551 PCI_ANY_ID, pdev)) != NULL) 1552 vga_arbiter_add_pci_device(pdev); 1553 1554 pr_info("loaded\n"); 1555 return rc; 1556 } 1557 subsys_initcall_sync(vga_arb_device_init); 1558