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