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 u64 limit; 552 resource_size_t start, end; 553 unsigned long flags; 554 int i; 555 556 /* Select the device owning the boot framebuffer if there is one */ 557 558 if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) 559 base |= (u64)screen_info.ext_lfb_base << 32; 560 561 limit = base + size; 562 563 /* Does firmware framebuffer belong to us? */ 564 for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) { 565 flags = pci_resource_flags(pdev, i); 566 567 if ((flags & IORESOURCE_MEM) == 0) 568 continue; 569 570 start = pci_resource_start(pdev, i); 571 end = pci_resource_end(pdev, i); 572 573 if (!start || !end) 574 continue; 575 576 if (base < start || limit >= end) 577 continue; 578 579 return true; 580 } 581 #endif 582 return false; 583 } 584 585 static bool vga_arb_integrated_gpu(struct device *dev) 586 { 587 #if defined(CONFIG_ACPI) 588 struct acpi_device *adev = ACPI_COMPANION(dev); 589 590 return adev && !strcmp(acpi_device_hid(adev), ACPI_VIDEO_HID); 591 #else 592 return false; 593 #endif 594 } 595 596 /* 597 * Return true if vgadev is a better default VGA device than the best one 598 * we've seen so far. 599 */ 600 static bool vga_is_boot_device(struct vga_device *vgadev) 601 { 602 struct vga_device *boot_vga = vgadev_find(vga_default_device()); 603 struct pci_dev *pdev = vgadev->pdev; 604 u16 cmd, boot_cmd; 605 606 /* 607 * We select the default VGA device in this order: 608 * Firmware framebuffer (see vga_arb_select_default_device()) 609 * Legacy VGA device (owns VGA_RSRC_LEGACY_MASK) 610 * Non-legacy integrated device (see vga_arb_select_default_device()) 611 * Non-legacy discrete device (see vga_arb_select_default_device()) 612 * Other device (see vga_arb_select_default_device()) 613 */ 614 615 /* 616 * We always prefer a firmware default device, so if we've already 617 * found one, there's no need to consider vgadev. 618 */ 619 if (boot_vga && boot_vga->is_firmware_default) 620 return false; 621 622 if (vga_is_firmware_default(pdev)) { 623 vgadev->is_firmware_default = true; 624 return true; 625 } 626 627 /* 628 * A legacy VGA device has MEM and IO enabled and any bridges 629 * leading to it have PCI_BRIDGE_CTL_VGA enabled so the legacy 630 * resources ([mem 0xa0000-0xbffff], [io 0x3b0-0x3bb], etc) are 631 * routed to it. 632 * 633 * We use the first one we find, so if we've already found one, 634 * vgadev is no better. 635 */ 636 if (boot_vga && 637 (boot_vga->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK) 638 return false; 639 640 if ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK) 641 return true; 642 643 /* 644 * If we haven't found a legacy VGA device, accept a non-legacy 645 * device. It may have either IO or MEM enabled, and bridges may 646 * not have PCI_BRIDGE_CTL_VGA enabled, so it may not be able to 647 * use legacy VGA resources. Prefer an integrated GPU over others. 648 */ 649 pci_read_config_word(pdev, PCI_COMMAND, &cmd); 650 if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) { 651 652 /* 653 * An integrated GPU overrides a previous non-legacy 654 * device. We expect only a single integrated GPU, but if 655 * there are more, we use the *last* because that was the 656 * previous behavior. 657 */ 658 if (vga_arb_integrated_gpu(&pdev->dev)) 659 return true; 660 661 /* 662 * We prefer the first non-legacy discrete device we find. 663 * If we already found one, vgadev is no better. 664 */ 665 if (boot_vga) { 666 pci_read_config_word(boot_vga->pdev, PCI_COMMAND, 667 &boot_cmd); 668 if (boot_cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) 669 return false; 670 } 671 return true; 672 } 673 674 /* 675 * vgadev has neither IO nor MEM enabled. If we haven't found any 676 * other VGA devices, it is the best candidate so far. 677 */ 678 if (!boot_vga) 679 return true; 680 681 return false; 682 } 683 684 /* 685 * Rules for using a bridge to control a VGA descendant decoding: if a bridge 686 * has only one VGA descendant then it can be used to control the VGA routing 687 * for that device. It should always use the bridge closest to the device to 688 * control it. If a bridge has a direct VGA descendant, but also have a sub- 689 * bridge VGA descendant then we cannot use that bridge to control the direct 690 * VGA descendant. So for every device we register, we need to iterate all 691 * its parent bridges so we can invalidate any devices using them properly. 692 */ 693 static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev) 694 { 695 struct vga_device *same_bridge_vgadev; 696 struct pci_bus *new_bus, *bus; 697 struct pci_dev *new_bridge, *bridge; 698 699 vgadev->bridge_has_one_vga = true; 700 701 if (list_empty(&vga_list)) { 702 vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n"); 703 return; 704 } 705 706 /* okay iterate the new devices bridge hierarachy */ 707 new_bus = vgadev->pdev->bus; 708 while (new_bus) { 709 new_bridge = new_bus->self; 710 711 /* go through list of devices already registered */ 712 list_for_each_entry(same_bridge_vgadev, &vga_list, list) { 713 bus = same_bridge_vgadev->pdev->bus; 714 bridge = bus->self; 715 716 /* see if the share a bridge with this device */ 717 if (new_bridge == bridge) { 718 /* 719 * If their direct parent bridge is the same 720 * as any bridge of this device then it can't 721 * be used for that device. 722 */ 723 same_bridge_vgadev->bridge_has_one_vga = false; 724 } 725 726 /* 727 * Now iterate the previous devices bridge hierarchy. 728 * If the new devices parent bridge is in the other 729 * devices hierarchy then we can't use it to control 730 * this device 731 */ 732 while (bus) { 733 bridge = bus->self; 734 735 if (bridge && bridge == vgadev->pdev->bus->self) 736 vgadev->bridge_has_one_vga = false; 737 738 bus = bus->parent; 739 } 740 } 741 new_bus = new_bus->parent; 742 } 743 744 if (vgadev->bridge_has_one_vga) 745 vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n"); 746 else 747 vgaarb_info(&vgadev->pdev->dev, "no bridge control possible\n"); 748 } 749 750 /* 751 * Currently, we assume that the "initial" setup of the system is 752 * not sane, that is we come up with conflicting devices and let 753 * the arbiter's client decides if devices decodes or not legacy 754 * things. 755 */ 756 static bool vga_arbiter_add_pci_device(struct pci_dev *pdev) 757 { 758 struct vga_device *vgadev; 759 unsigned long flags; 760 struct pci_bus *bus; 761 struct pci_dev *bridge; 762 u16 cmd; 763 764 /* Only deal with VGA class devices */ 765 if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA) 766 return false; 767 768 /* Allocate structure */ 769 vgadev = kzalloc(sizeof(struct vga_device), GFP_KERNEL); 770 if (vgadev == NULL) { 771 vgaarb_err(&pdev->dev, "failed to allocate VGA arbiter data\n"); 772 /* 773 * What to do on allocation failure ? For now, let's just do 774 * nothing, I'm not sure there is anything saner to be done. 775 */ 776 return false; 777 } 778 779 /* Take lock & check for duplicates */ 780 spin_lock_irqsave(&vga_lock, flags); 781 if (vgadev_find(pdev) != NULL) { 782 BUG_ON(1); 783 goto fail; 784 } 785 vgadev->pdev = pdev; 786 787 /* By default, assume we decode everything */ 788 vgadev->decodes = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM | 789 VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM; 790 791 /* by default mark it as decoding */ 792 vga_decode_count++; 793 /* Mark that we "own" resources based on our enables, we will 794 * clear that below if the bridge isn't forwarding 795 */ 796 pci_read_config_word(pdev, PCI_COMMAND, &cmd); 797 if (cmd & PCI_COMMAND_IO) 798 vgadev->owns |= VGA_RSRC_LEGACY_IO; 799 if (cmd & PCI_COMMAND_MEMORY) 800 vgadev->owns |= VGA_RSRC_LEGACY_MEM; 801 802 /* Check if VGA cycles can get down to us */ 803 bus = pdev->bus; 804 while (bus) { 805 bridge = bus->self; 806 if (bridge) { 807 u16 l; 808 809 pci_read_config_word(bridge, PCI_BRIDGE_CONTROL, &l); 810 if (!(l & PCI_BRIDGE_CTL_VGA)) { 811 vgadev->owns = 0; 812 break; 813 } 814 } 815 bus = bus->parent; 816 } 817 818 if (vga_is_boot_device(vgadev)) { 819 vgaarb_info(&pdev->dev, "setting as boot VGA device%s\n", 820 vga_default_device() ? 821 " (overriding previous)" : ""); 822 vga_set_default_device(pdev); 823 } 824 825 vga_arbiter_check_bridge_sharing(vgadev); 826 827 /* Add to the list */ 828 list_add_tail(&vgadev->list, &vga_list); 829 vga_count++; 830 vgaarb_info(&pdev->dev, "VGA device added: decodes=%s,owns=%s,locks=%s\n", 831 vga_iostate_to_str(vgadev->decodes), 832 vga_iostate_to_str(vgadev->owns), 833 vga_iostate_to_str(vgadev->locks)); 834 835 spin_unlock_irqrestore(&vga_lock, flags); 836 return true; 837 fail: 838 spin_unlock_irqrestore(&vga_lock, flags); 839 kfree(vgadev); 840 return false; 841 } 842 843 static bool vga_arbiter_del_pci_device(struct pci_dev *pdev) 844 { 845 struct vga_device *vgadev; 846 unsigned long flags; 847 bool ret = true; 848 849 spin_lock_irqsave(&vga_lock, flags); 850 vgadev = vgadev_find(pdev); 851 if (vgadev == NULL) { 852 ret = false; 853 goto bail; 854 } 855 856 if (vga_default == pdev) 857 vga_set_default_device(NULL); 858 859 if (vgadev->decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM)) 860 vga_decode_count--; 861 862 /* Remove entry from list */ 863 list_del(&vgadev->list); 864 vga_count--; 865 866 /* Wake up all possible waiters */ 867 wake_up_all(&vga_wait_queue); 868 bail: 869 spin_unlock_irqrestore(&vga_lock, flags); 870 kfree(vgadev); 871 return ret; 872 } 873 874 /* this is called with the lock */ 875 static inline void vga_update_device_decodes(struct vga_device *vgadev, 876 int new_decodes) 877 { 878 struct device *dev = &vgadev->pdev->dev; 879 int old_decodes, decodes_removed, decodes_unlocked; 880 881 old_decodes = vgadev->decodes; 882 decodes_removed = ~new_decodes & old_decodes; 883 decodes_unlocked = vgadev->locks & decodes_removed; 884 vgadev->decodes = new_decodes; 885 886 vgaarb_info(dev, "changed VGA decodes: 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, 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, decodes); 930 931 /* XXX if somebody is going from "doesn't decode" to "decodes" state 932 * here, additional care must be taken as we may have pending owner 933 * ship of non-legacy region ... 934 */ 935 bail: 936 spin_unlock_irqrestore(&vga_lock, flags); 937 } 938 939 /** 940 * vga_set_legacy_decoding 941 * @pdev: pci device of the VGA card 942 * @decodes: bit mask of what legacy regions the card decodes 943 * 944 * Indicates to the arbiter if the card decodes legacy VGA IOs, legacy VGA 945 * Memory, both, or none. All cards default to both, the card driver (fbdev for 946 * example) should tell the arbiter if it has disabled legacy decoding, so the 947 * card can be left out of the arbitration process (and can be safe to take 948 * interrupts at any time. 949 */ 950 void vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes) 951 { 952 __vga_set_legacy_decoding(pdev, decodes, false); 953 } 954 EXPORT_SYMBOL(vga_set_legacy_decoding); 955 956 /** 957 * vga_client_register - register or unregister a VGA arbitration client 958 * @pdev: pci device of the VGA client 959 * @set_decode: vga decode change callback 960 * 961 * Clients have two callback mechanisms they can use. 962 * 963 * @set_decode callback: If a client can disable its GPU VGA resource, it 964 * will get a callback from this to set the encode/decode state. 965 * 966 * Rationale: we cannot disable VGA decode resources unconditionally some single 967 * GPU laptops seem to require ACPI or BIOS access to the VGA registers to 968 * control things like backlights etc. Hopefully newer multi-GPU laptops do 969 * something saner, and desktops won't have any special ACPI for this. The 970 * driver will get a callback when VGA arbitration is first used by userspace 971 * since some older X servers have issues. 972 * 973 * This function does not check whether a client for @pdev has been registered 974 * already. 975 * 976 * To unregister just call vga_client_unregister(). 977 * 978 * Returns: 0 on success, -1 on failure 979 */ 980 int vga_client_register(struct pci_dev *pdev, 981 unsigned int (*set_decode)(struct pci_dev *pdev, bool decode)) 982 { 983 int ret = -ENODEV; 984 struct vga_device *vgadev; 985 unsigned long flags; 986 987 spin_lock_irqsave(&vga_lock, flags); 988 vgadev = vgadev_find(pdev); 989 if (!vgadev) 990 goto bail; 991 992 vgadev->set_decode = set_decode; 993 ret = 0; 994 995 bail: 996 spin_unlock_irqrestore(&vga_lock, flags); 997 return ret; 998 999 } 1000 EXPORT_SYMBOL(vga_client_register); 1001 1002 /* 1003 * Char driver implementation 1004 * 1005 * Semantics is: 1006 * 1007 * open : open user instance of the arbitrer. by default, it's 1008 * attached to the default VGA device of the system. 1009 * 1010 * close : close user instance, release locks 1011 * 1012 * read : return a string indicating the status of the target. 1013 * an IO state string is of the form {io,mem,io+mem,none}, 1014 * mc and ic are respectively mem and io lock counts (for 1015 * debugging/diagnostic only). "decodes" indicate what the 1016 * card currently decodes, "owns" indicates what is currently 1017 * enabled on it, and "locks" indicates what is locked by this 1018 * card. If the card is unplugged, we get "invalid" then for 1019 * card_ID and an -ENODEV error is returned for any command 1020 * until a new card is targeted 1021 * 1022 * "<card_ID>,decodes=<io_state>,owns=<io_state>,locks=<io_state> (ic,mc)" 1023 * 1024 * write : write a command to the arbiter. List of commands is: 1025 * 1026 * target <card_ID> : switch target to card <card_ID> (see below) 1027 * lock <io_state> : acquires locks on target ("none" is invalid io_state) 1028 * trylock <io_state> : non-blocking acquire locks on target 1029 * unlock <io_state> : release locks on target 1030 * unlock all : release all locks on target held by this user 1031 * decodes <io_state> : set the legacy decoding attributes for the card 1032 * 1033 * poll : event if something change on any card (not just the target) 1034 * 1035 * card_ID is of the form "PCI:domain:bus:dev.fn". It can be set to "default" 1036 * to go back to the system default card (TODO: not implemented yet). 1037 * Currently, only PCI is supported as a prefix, but the userland API may 1038 * support other bus types in the future, even if the current kernel 1039 * implementation doesn't. 1040 * 1041 * Note about locks: 1042 * 1043 * The driver keeps track of which user has what locks on which card. It 1044 * supports stacking, like the kernel one. This complexifies the implementation 1045 * a bit, but makes the arbiter more tolerant to userspace problems and able 1046 * to properly cleanup in all cases when a process dies. 1047 * Currently, a max of 16 cards simultaneously can have locks issued from 1048 * userspace for a given user (file descriptor instance) of the arbiter. 1049 * 1050 * If the device is hot-unplugged, there is a hook inside the module to notify 1051 * they being added/removed in the system and automatically added/removed in 1052 * the arbiter. 1053 */ 1054 1055 #define MAX_USER_CARDS CONFIG_VGA_ARB_MAX_GPUS 1056 #define PCI_INVALID_CARD ((struct pci_dev *)-1UL) 1057 1058 /* 1059 * Each user has an array of these, tracking which cards have locks 1060 */ 1061 struct vga_arb_user_card { 1062 struct pci_dev *pdev; 1063 unsigned int mem_cnt; 1064 unsigned int io_cnt; 1065 }; 1066 1067 struct vga_arb_private { 1068 struct list_head list; 1069 struct pci_dev *target; 1070 struct vga_arb_user_card cards[MAX_USER_CARDS]; 1071 spinlock_t lock; 1072 }; 1073 1074 static LIST_HEAD(vga_user_list); 1075 static DEFINE_SPINLOCK(vga_user_lock); 1076 1077 1078 /* 1079 * This function gets a string in the format: "PCI:domain:bus:dev.fn" and 1080 * returns the respective values. If the string is not in this format, 1081 * it returns 0. 1082 */ 1083 static int vga_pci_str_to_vars(char *buf, int count, unsigned int *domain, 1084 unsigned int *bus, unsigned int *devfn) 1085 { 1086 int n; 1087 unsigned int slot, func; 1088 1089 1090 n = sscanf(buf, "PCI:%x:%x:%x.%x", domain, bus, &slot, &func); 1091 if (n != 4) 1092 return 0; 1093 1094 *devfn = PCI_DEVFN(slot, func); 1095 1096 return 1; 1097 } 1098 1099 static ssize_t vga_arb_read(struct file *file, char __user *buf, 1100 size_t count, loff_t *ppos) 1101 { 1102 struct vga_arb_private *priv = file->private_data; 1103 struct vga_device *vgadev; 1104 struct pci_dev *pdev; 1105 unsigned long flags; 1106 size_t len; 1107 int rc; 1108 char *lbuf; 1109 1110 lbuf = kmalloc(1024, GFP_KERNEL); 1111 if (lbuf == NULL) 1112 return -ENOMEM; 1113 1114 /* Protects vga_list */ 1115 spin_lock_irqsave(&vga_lock, flags); 1116 1117 /* If we are targeting the default, use it */ 1118 pdev = priv->target; 1119 if (pdev == NULL || pdev == PCI_INVALID_CARD) { 1120 spin_unlock_irqrestore(&vga_lock, flags); 1121 len = sprintf(lbuf, "invalid"); 1122 goto done; 1123 } 1124 1125 /* Find card vgadev structure */ 1126 vgadev = vgadev_find(pdev); 1127 if (vgadev == NULL) { 1128 /* Wow, it's not in the list, that shouldn't happen, 1129 * let's fix us up and return invalid card 1130 */ 1131 spin_unlock_irqrestore(&vga_lock, flags); 1132 len = sprintf(lbuf, "invalid"); 1133 goto done; 1134 } 1135 1136 /* Fill the buffer with infos */ 1137 len = snprintf(lbuf, 1024, 1138 "count:%d,PCI:%s,decodes=%s,owns=%s,locks=%s(%u:%u)\n", 1139 vga_decode_count, pci_name(pdev), 1140 vga_iostate_to_str(vgadev->decodes), 1141 vga_iostate_to_str(vgadev->owns), 1142 vga_iostate_to_str(vgadev->locks), 1143 vgadev->io_lock_cnt, vgadev->mem_lock_cnt); 1144 1145 spin_unlock_irqrestore(&vga_lock, flags); 1146 done: 1147 1148 /* Copy that to user */ 1149 if (len > count) 1150 len = count; 1151 rc = copy_to_user(buf, lbuf, len); 1152 kfree(lbuf); 1153 if (rc) 1154 return -EFAULT; 1155 return len; 1156 } 1157 1158 /* 1159 * TODO: To avoid parsing inside kernel and to improve the speed we may 1160 * consider use ioctl here 1161 */ 1162 static ssize_t vga_arb_write(struct file *file, const char __user *buf, 1163 size_t count, loff_t *ppos) 1164 { 1165 struct vga_arb_private *priv = file->private_data; 1166 struct vga_arb_user_card *uc = NULL; 1167 struct pci_dev *pdev; 1168 1169 unsigned int io_state; 1170 1171 char kbuf[64], *curr_pos; 1172 size_t remaining = count; 1173 1174 int ret_val; 1175 int i; 1176 1177 if (count >= sizeof(kbuf)) 1178 return -EINVAL; 1179 if (copy_from_user(kbuf, buf, count)) 1180 return -EFAULT; 1181 curr_pos = kbuf; 1182 kbuf[count] = '\0'; /* Just to make sure... */ 1183 1184 if (strncmp(curr_pos, "lock ", 5) == 0) { 1185 curr_pos += 5; 1186 remaining -= 5; 1187 1188 pr_debug("client 0x%p called 'lock'\n", priv); 1189 1190 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { 1191 ret_val = -EPROTO; 1192 goto done; 1193 } 1194 if (io_state == VGA_RSRC_NONE) { 1195 ret_val = -EPROTO; 1196 goto done; 1197 } 1198 1199 pdev = priv->target; 1200 if (priv->target == NULL) { 1201 ret_val = -ENODEV; 1202 goto done; 1203 } 1204 1205 vga_get_uninterruptible(pdev, io_state); 1206 1207 /* Update the client's locks lists... */ 1208 for (i = 0; i < MAX_USER_CARDS; i++) { 1209 if (priv->cards[i].pdev == pdev) { 1210 if (io_state & VGA_RSRC_LEGACY_IO) 1211 priv->cards[i].io_cnt++; 1212 if (io_state & VGA_RSRC_LEGACY_MEM) 1213 priv->cards[i].mem_cnt++; 1214 break; 1215 } 1216 } 1217 1218 ret_val = count; 1219 goto done; 1220 } else if (strncmp(curr_pos, "unlock ", 7) == 0) { 1221 curr_pos += 7; 1222 remaining -= 7; 1223 1224 pr_debug("client 0x%p called 'unlock'\n", priv); 1225 1226 if (strncmp(curr_pos, "all", 3) == 0) 1227 io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; 1228 else { 1229 if (!vga_str_to_iostate 1230 (curr_pos, remaining, &io_state)) { 1231 ret_val = -EPROTO; 1232 goto done; 1233 } 1234 /* TODO: Add this? 1235 if (io_state == VGA_RSRC_NONE) { 1236 ret_val = -EPROTO; 1237 goto done; 1238 } 1239 */ 1240 } 1241 1242 pdev = priv->target; 1243 if (priv->target == NULL) { 1244 ret_val = -ENODEV; 1245 goto done; 1246 } 1247 for (i = 0; i < MAX_USER_CARDS; i++) { 1248 if (priv->cards[i].pdev == pdev) 1249 uc = &priv->cards[i]; 1250 } 1251 1252 if (!uc) { 1253 ret_val = -EINVAL; 1254 goto done; 1255 } 1256 1257 if (io_state & VGA_RSRC_LEGACY_IO && uc->io_cnt == 0) { 1258 ret_val = -EINVAL; 1259 goto done; 1260 } 1261 1262 if (io_state & VGA_RSRC_LEGACY_MEM && uc->mem_cnt == 0) { 1263 ret_val = -EINVAL; 1264 goto done; 1265 } 1266 1267 vga_put(pdev, io_state); 1268 1269 if (io_state & VGA_RSRC_LEGACY_IO) 1270 uc->io_cnt--; 1271 if (io_state & VGA_RSRC_LEGACY_MEM) 1272 uc->mem_cnt--; 1273 1274 ret_val = count; 1275 goto done; 1276 } else if (strncmp(curr_pos, "trylock ", 8) == 0) { 1277 curr_pos += 8; 1278 remaining -= 8; 1279 1280 pr_debug("client 0x%p called 'trylock'\n", priv); 1281 1282 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { 1283 ret_val = -EPROTO; 1284 goto done; 1285 } 1286 /* TODO: Add this? 1287 if (io_state == VGA_RSRC_NONE) { 1288 ret_val = -EPROTO; 1289 goto done; 1290 } 1291 */ 1292 1293 pdev = priv->target; 1294 if (priv->target == NULL) { 1295 ret_val = -ENODEV; 1296 goto done; 1297 } 1298 1299 if (vga_tryget(pdev, io_state)) { 1300 /* Update the client's locks lists... */ 1301 for (i = 0; i < MAX_USER_CARDS; i++) { 1302 if (priv->cards[i].pdev == pdev) { 1303 if (io_state & VGA_RSRC_LEGACY_IO) 1304 priv->cards[i].io_cnt++; 1305 if (io_state & VGA_RSRC_LEGACY_MEM) 1306 priv->cards[i].mem_cnt++; 1307 break; 1308 } 1309 } 1310 ret_val = count; 1311 goto done; 1312 } else { 1313 ret_val = -EBUSY; 1314 goto done; 1315 } 1316 1317 } else if (strncmp(curr_pos, "target ", 7) == 0) { 1318 unsigned int domain, bus, devfn; 1319 struct vga_device *vgadev; 1320 1321 curr_pos += 7; 1322 remaining -= 7; 1323 pr_debug("client 0x%p called 'target'\n", priv); 1324 /* if target is default */ 1325 if (!strncmp(curr_pos, "default", 7)) 1326 pdev = pci_dev_get(vga_default_device()); 1327 else { 1328 if (!vga_pci_str_to_vars(curr_pos, remaining, 1329 &domain, &bus, &devfn)) { 1330 ret_val = -EPROTO; 1331 goto done; 1332 } 1333 pdev = pci_get_domain_bus_and_slot(domain, bus, devfn); 1334 if (!pdev) { 1335 pr_debug("invalid PCI address %04x:%02x:%02x.%x\n", 1336 domain, bus, PCI_SLOT(devfn), 1337 PCI_FUNC(devfn)); 1338 ret_val = -ENODEV; 1339 goto done; 1340 } 1341 1342 pr_debug("%s ==> %04x:%02x:%02x.%x pdev %p\n", curr_pos, 1343 domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn), 1344 pdev); 1345 } 1346 1347 vgadev = vgadev_find(pdev); 1348 pr_debug("vgadev %p\n", vgadev); 1349 if (vgadev == NULL) { 1350 if (pdev) { 1351 vgaarb_dbg(&pdev->dev, "not a VGA device\n"); 1352 pci_dev_put(pdev); 1353 } 1354 1355 ret_val = -ENODEV; 1356 goto done; 1357 } 1358 1359 priv->target = pdev; 1360 for (i = 0; i < MAX_USER_CARDS; i++) { 1361 if (priv->cards[i].pdev == pdev) 1362 break; 1363 if (priv->cards[i].pdev == NULL) { 1364 priv->cards[i].pdev = pdev; 1365 priv->cards[i].io_cnt = 0; 1366 priv->cards[i].mem_cnt = 0; 1367 break; 1368 } 1369 } 1370 if (i == MAX_USER_CARDS) { 1371 vgaarb_dbg(&pdev->dev, "maximum user cards (%d) number reached, ignoring this one!\n", 1372 MAX_USER_CARDS); 1373 pci_dev_put(pdev); 1374 /* XXX: which value to return? */ 1375 ret_val = -ENOMEM; 1376 goto done; 1377 } 1378 1379 ret_val = count; 1380 pci_dev_put(pdev); 1381 goto done; 1382 1383 1384 } else if (strncmp(curr_pos, "decodes ", 8) == 0) { 1385 curr_pos += 8; 1386 remaining -= 8; 1387 pr_debug("client 0x%p called 'decodes'\n", priv); 1388 1389 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { 1390 ret_val = -EPROTO; 1391 goto done; 1392 } 1393 pdev = priv->target; 1394 if (priv->target == NULL) { 1395 ret_val = -ENODEV; 1396 goto done; 1397 } 1398 1399 __vga_set_legacy_decoding(pdev, io_state, true); 1400 ret_val = count; 1401 goto done; 1402 } 1403 /* If we got here, the message written is not part of the protocol! */ 1404 return -EPROTO; 1405 1406 done: 1407 return ret_val; 1408 } 1409 1410 static __poll_t vga_arb_fpoll(struct file *file, poll_table *wait) 1411 { 1412 pr_debug("%s\n", __func__); 1413 1414 poll_wait(file, &vga_wait_queue, wait); 1415 return EPOLLIN; 1416 } 1417 1418 static int vga_arb_open(struct inode *inode, struct file *file) 1419 { 1420 struct vga_arb_private *priv; 1421 unsigned long flags; 1422 1423 pr_debug("%s\n", __func__); 1424 1425 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 1426 if (priv == NULL) 1427 return -ENOMEM; 1428 spin_lock_init(&priv->lock); 1429 file->private_data = priv; 1430 1431 spin_lock_irqsave(&vga_user_lock, flags); 1432 list_add(&priv->list, &vga_user_list); 1433 spin_unlock_irqrestore(&vga_user_lock, flags); 1434 1435 /* Set the client' lists of locks */ 1436 priv->target = vga_default_device(); /* Maybe this is still null! */ 1437 priv->cards[0].pdev = priv->target; 1438 priv->cards[0].io_cnt = 0; 1439 priv->cards[0].mem_cnt = 0; 1440 1441 1442 return 0; 1443 } 1444 1445 static int vga_arb_release(struct inode *inode, struct file *file) 1446 { 1447 struct vga_arb_private *priv = file->private_data; 1448 struct vga_arb_user_card *uc; 1449 unsigned long flags; 1450 int i; 1451 1452 pr_debug("%s\n", __func__); 1453 1454 spin_lock_irqsave(&vga_user_lock, flags); 1455 list_del(&priv->list); 1456 for (i = 0; i < MAX_USER_CARDS; i++) { 1457 uc = &priv->cards[i]; 1458 if (uc->pdev == NULL) 1459 continue; 1460 vgaarb_dbg(&uc->pdev->dev, "uc->io_cnt == %d, uc->mem_cnt == %d\n", 1461 uc->io_cnt, uc->mem_cnt); 1462 while (uc->io_cnt--) 1463 vga_put(uc->pdev, VGA_RSRC_LEGACY_IO); 1464 while (uc->mem_cnt--) 1465 vga_put(uc->pdev, VGA_RSRC_LEGACY_MEM); 1466 } 1467 spin_unlock_irqrestore(&vga_user_lock, flags); 1468 1469 kfree(priv); 1470 1471 return 0; 1472 } 1473 1474 /* 1475 * callback any registered clients to let them know we have a 1476 * change in VGA cards 1477 */ 1478 static void vga_arbiter_notify_clients(void) 1479 { 1480 struct vga_device *vgadev; 1481 unsigned long flags; 1482 uint32_t new_decodes; 1483 bool new_state; 1484 1485 if (!vga_arbiter_used) 1486 return; 1487 1488 spin_lock_irqsave(&vga_lock, flags); 1489 list_for_each_entry(vgadev, &vga_list, list) { 1490 if (vga_count > 1) 1491 new_state = false; 1492 else 1493 new_state = true; 1494 if (vgadev->set_decode) { 1495 new_decodes = vgadev->set_decode(vgadev->pdev, 1496 new_state); 1497 vga_update_device_decodes(vgadev, new_decodes); 1498 } 1499 } 1500 spin_unlock_irqrestore(&vga_lock, flags); 1501 } 1502 1503 static int pci_notify(struct notifier_block *nb, unsigned long action, 1504 void *data) 1505 { 1506 struct device *dev = data; 1507 struct pci_dev *pdev = to_pci_dev(dev); 1508 bool notify = false; 1509 1510 vgaarb_dbg(dev, "%s\n", __func__); 1511 1512 /* For now we're only intereted in devices added and removed. I didn't 1513 * test this thing here, so someone needs to double check for the 1514 * cases of hotplugable vga cards. */ 1515 if (action == BUS_NOTIFY_ADD_DEVICE) 1516 notify = vga_arbiter_add_pci_device(pdev); 1517 else if (action == BUS_NOTIFY_DEL_DEVICE) 1518 notify = vga_arbiter_del_pci_device(pdev); 1519 1520 if (notify) 1521 vga_arbiter_notify_clients(); 1522 return 0; 1523 } 1524 1525 static struct notifier_block pci_notifier = { 1526 .notifier_call = pci_notify, 1527 }; 1528 1529 static const struct file_operations vga_arb_device_fops = { 1530 .read = vga_arb_read, 1531 .write = vga_arb_write, 1532 .poll = vga_arb_fpoll, 1533 .open = vga_arb_open, 1534 .release = vga_arb_release, 1535 .llseek = noop_llseek, 1536 }; 1537 1538 static struct miscdevice vga_arb_device = { 1539 MISC_DYNAMIC_MINOR, "vga_arbiter", &vga_arb_device_fops 1540 }; 1541 1542 static int __init vga_arb_device_init(void) 1543 { 1544 int rc; 1545 struct pci_dev *pdev; 1546 1547 rc = misc_register(&vga_arb_device); 1548 if (rc < 0) 1549 pr_err("error %d registering device\n", rc); 1550 1551 bus_register_notifier(&pci_bus_type, &pci_notifier); 1552 1553 /* We add all PCI devices satisfying VGA class in the arbiter by 1554 * default */ 1555 pdev = NULL; 1556 while ((pdev = 1557 pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, 1558 PCI_ANY_ID, pdev)) != NULL) 1559 vga_arbiter_add_pci_device(pdev); 1560 1561 pr_info("loaded\n"); 1562 return rc; 1563 } 1564 subsys_initcall_sync(vga_arb_device_init); 1565