1 /* 2 * vgaarb.c: Implements the VGA arbitration. For details refer to 3 * Documentation/gpu/vgaarbiter.rst 4 * 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 * Permission is hereby granted, free of charge, to any person obtaining a 11 * copy of this software and associated documentation files (the "Software"), 12 * to deal in the Software without restriction, including without limitation 13 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 14 * and/or sell copies of the Software, and to permit persons to whom the 15 * Software is furnished to do so, subject to the following conditions: 16 * 17 * The above copyright notice and this permission notice (including the next 18 * paragraph) shall be included in all copies or substantial portions of the 19 * Software. 20 * 21 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 22 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 23 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 24 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 25 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 26 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 27 * DEALINGS 28 * IN THE SOFTWARE. 29 * 30 */ 31 32 #define pr_fmt(fmt) "vgaarb: " fmt 33 34 #define vgaarb_dbg(dev, fmt, arg...) dev_dbg(dev, "vgaarb: " fmt, ##arg) 35 #define vgaarb_info(dev, fmt, arg...) dev_info(dev, "vgaarb: " fmt, ##arg) 36 #define vgaarb_err(dev, fmt, arg...) dev_err(dev, "vgaarb: " fmt, ##arg) 37 38 #include <linux/module.h> 39 #include <linux/kernel.h> 40 #include <linux/pci.h> 41 #include <linux/errno.h> 42 #include <linux/init.h> 43 #include <linux/list.h> 44 #include <linux/sched/signal.h> 45 #include <linux/wait.h> 46 #include <linux/spinlock.h> 47 #include <linux/poll.h> 48 #include <linux/miscdevice.h> 49 #include <linux/slab.h> 50 #include <linux/screen_info.h> 51 #include <linux/vt.h> 52 #include <linux/console.h> 53 #include <linux/acpi.h> 54 55 #include <linux/uaccess.h> 56 57 #include <linux/vgaarb.h> 58 59 static void vga_arbiter_notify_clients(void); 60 /* 61 * We keep a list of all vga devices in the system to speed 62 * up the various operations of the arbiter 63 */ 64 struct vga_device { 65 struct list_head list; 66 struct pci_dev *pdev; 67 unsigned int decodes; /* what does it decodes */ 68 unsigned int owns; /* what does it owns */ 69 unsigned int locks; /* what does it locks */ 70 unsigned int io_lock_cnt; /* legacy IO lock count */ 71 unsigned int mem_lock_cnt; /* legacy MEM lock count */ 72 unsigned int io_norm_cnt; /* normal IO count */ 73 unsigned int mem_norm_cnt; /* normal MEM count */ 74 bool bridge_has_one_vga; 75 bool is_firmware_default; /* device selected by firmware */ 76 unsigned int (*set_decode)(struct pci_dev *pdev, bool decode); 77 }; 78 79 static LIST_HEAD(vga_list); 80 static int vga_count, vga_decode_count; 81 static bool vga_arbiter_used; 82 static DEFINE_SPINLOCK(vga_lock); 83 static DECLARE_WAIT_QUEUE_HEAD(vga_wait_queue); 84 85 86 static const char *vga_iostate_to_str(unsigned int iostate) 87 { 88 /* Ignore VGA_RSRC_IO and VGA_RSRC_MEM */ 89 iostate &= VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; 90 switch (iostate) { 91 case VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM: 92 return "io+mem"; 93 case VGA_RSRC_LEGACY_IO: 94 return "io"; 95 case VGA_RSRC_LEGACY_MEM: 96 return "mem"; 97 } 98 return "none"; 99 } 100 101 static int vga_str_to_iostate(char *buf, int str_size, int *io_state) 102 { 103 /* we could in theory hand out locks on IO and mem 104 * separately to userspace but it can cause deadlocks */ 105 if (strncmp(buf, "none", 4) == 0) { 106 *io_state = VGA_RSRC_NONE; 107 return 1; 108 } 109 110 /* XXX We're not chekcing the str_size! */ 111 if (strncmp(buf, "io+mem", 6) == 0) 112 goto both; 113 else if (strncmp(buf, "io", 2) == 0) 114 goto both; 115 else if (strncmp(buf, "mem", 3) == 0) 116 goto both; 117 return 0; 118 both: 119 *io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; 120 return 1; 121 } 122 123 /* this is only used a cookie - it should not be dereferenced */ 124 static struct pci_dev *vga_default; 125 126 static void vga_arb_device_card_gone(struct pci_dev *pdev); 127 128 /* Find somebody in our list */ 129 static struct vga_device *vgadev_find(struct pci_dev *pdev) 130 { 131 struct vga_device *vgadev; 132 133 list_for_each_entry(vgadev, &vga_list, list) 134 if (pdev == vgadev->pdev) 135 return vgadev; 136 return NULL; 137 } 138 139 /** 140 * vga_default_device - return the default VGA device, for vgacon 141 * 142 * This can be defined by the platform. The default implementation 143 * is rather dumb and will probably only work properly on single 144 * vga card setups and/or x86 platforms. 145 * 146 * If your VGA default device is not PCI, you'll have to return 147 * NULL here. In this case, I assume it will not conflict with 148 * any PCI card. If this is not true, I'll have to define two archs 149 * hooks for enabling/disabling the VGA default device if that is 150 * possible. This may be a problem with real _ISA_ VGA cards, in 151 * addition to a PCI one. I don't know at this point how to deal 152 * with that card. Can theirs IOs be disabled at all ? If not, then 153 * I suppose it's a matter of having the proper arch hook telling 154 * us about it, so we basically never allow anybody to succeed a 155 * vga_get()... 156 */ 157 struct pci_dev *vga_default_device(void) 158 { 159 return vga_default; 160 } 161 EXPORT_SYMBOL_GPL(vga_default_device); 162 163 void vga_set_default_device(struct pci_dev *pdev) 164 { 165 if (vga_default == pdev) 166 return; 167 168 pci_dev_put(vga_default); 169 vga_default = pci_dev_get(pdev); 170 } 171 172 /** 173 * vga_remove_vgacon - deactivete vga console 174 * 175 * Unbind and unregister vgacon in case pdev is the default vga 176 * device. Can be called by gpu drivers on initialization to make 177 * sure vga register access done by vgacon will not disturb the 178 * device. 179 * 180 * @pdev: pci device. 181 */ 182 #if !defined(CONFIG_VGA_CONSOLE) 183 int vga_remove_vgacon(struct pci_dev *pdev) 184 { 185 return 0; 186 } 187 #elif !defined(CONFIG_DUMMY_CONSOLE) 188 int vga_remove_vgacon(struct pci_dev *pdev) 189 { 190 return -ENODEV; 191 } 192 #else 193 int vga_remove_vgacon(struct pci_dev *pdev) 194 { 195 int ret = 0; 196 197 if (pdev != vga_default) 198 return 0; 199 vgaarb_info(&pdev->dev, "deactivate vga console\n"); 200 201 console_lock(); 202 if (con_is_bound(&vga_con)) 203 ret = do_take_over_console(&dummy_con, 0, 204 MAX_NR_CONSOLES - 1, 1); 205 if (ret == 0) { 206 ret = do_unregister_con_driver(&vga_con); 207 208 /* Ignore "already unregistered". */ 209 if (ret == -ENODEV) 210 ret = 0; 211 } 212 console_unlock(); 213 214 return ret; 215 } 216 #endif 217 EXPORT_SYMBOL(vga_remove_vgacon); 218 219 /* If we don't ever use VGA arb we should avoid 220 turning off anything anywhere due to old X servers getting 221 confused about the boot device not being VGA */ 222 static void vga_check_first_use(void) 223 { 224 /* we should inform all GPUs in the system that 225 * VGA arb has occurred and to try and disable resources 226 * if they can */ 227 if (!vga_arbiter_used) { 228 vga_arbiter_used = true; 229 vga_arbiter_notify_clients(); 230 } 231 } 232 233 static struct vga_device *__vga_tryget(struct vga_device *vgadev, 234 unsigned int rsrc) 235 { 236 struct device *dev = &vgadev->pdev->dev; 237 unsigned int wants, legacy_wants, match; 238 struct vga_device *conflict; 239 unsigned int pci_bits; 240 u32 flags = 0; 241 242 /* Account for "normal" resources to lock. If we decode the legacy, 243 * counterpart, we need to request it as well 244 */ 245 if ((rsrc & VGA_RSRC_NORMAL_IO) && 246 (vgadev->decodes & VGA_RSRC_LEGACY_IO)) 247 rsrc |= VGA_RSRC_LEGACY_IO; 248 if ((rsrc & VGA_RSRC_NORMAL_MEM) && 249 (vgadev->decodes & VGA_RSRC_LEGACY_MEM)) 250 rsrc |= VGA_RSRC_LEGACY_MEM; 251 252 vgaarb_dbg(dev, "%s: %d\n", __func__, rsrc); 253 vgaarb_dbg(dev, "%s: owns: %d\n", __func__, vgadev->owns); 254 255 /* Check what resources we need to acquire */ 256 wants = rsrc & ~vgadev->owns; 257 258 /* We already own everything, just mark locked & bye bye */ 259 if (wants == 0) 260 goto lock_them; 261 262 /* We don't need to request a legacy resource, we just enable 263 * appropriate decoding and go 264 */ 265 legacy_wants = wants & VGA_RSRC_LEGACY_MASK; 266 if (legacy_wants == 0) 267 goto enable_them; 268 269 /* Ok, we don't, let's find out how we need to kick off */ 270 list_for_each_entry(conflict, &vga_list, list) { 271 unsigned int lwants = legacy_wants; 272 unsigned int change_bridge = 0; 273 274 /* Don't conflict with myself */ 275 if (vgadev == conflict) 276 continue; 277 278 /* We have a possible conflict. before we go further, we must 279 * check if we sit on the same bus as the conflicting device. 280 * if we don't, then we must tie both IO and MEM resources 281 * together since there is only a single bit controlling 282 * VGA forwarding on P2P bridges 283 */ 284 if (vgadev->pdev->bus != conflict->pdev->bus) { 285 change_bridge = 1; 286 lwants = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; 287 } 288 289 /* Check if the guy has a lock on the resource. If he does, 290 * return the conflicting entry 291 */ 292 if (conflict->locks & lwants) 293 return conflict; 294 295 /* Ok, now check if it owns the resource we want. We can 296 * lock resources that are not decoded, therefore a device 297 * can own resources it doesn't decode. 298 */ 299 match = lwants & conflict->owns; 300 if (!match) 301 continue; 302 303 /* looks like he doesn't have a lock, we can steal 304 * them from him 305 */ 306 307 flags = 0; 308 pci_bits = 0; 309 310 /* If we can't control legacy resources via the bridge, we 311 * also need to disable normal decoding. 312 */ 313 if (!conflict->bridge_has_one_vga) { 314 if ((match & conflict->decodes) & VGA_RSRC_LEGACY_MEM) 315 pci_bits |= PCI_COMMAND_MEMORY; 316 if ((match & conflict->decodes) & VGA_RSRC_LEGACY_IO) 317 pci_bits |= PCI_COMMAND_IO; 318 319 if (pci_bits) 320 flags |= PCI_VGA_STATE_CHANGE_DECODES; 321 } 322 323 if (change_bridge) 324 flags |= PCI_VGA_STATE_CHANGE_BRIDGE; 325 326 pci_set_vga_state(conflict->pdev, false, pci_bits, flags); 327 conflict->owns &= ~match; 328 329 /* If we disabled normal decoding, reflect it in owns */ 330 if (pci_bits & PCI_COMMAND_MEMORY) 331 conflict->owns &= ~VGA_RSRC_NORMAL_MEM; 332 if (pci_bits & PCI_COMMAND_IO) 333 conflict->owns &= ~VGA_RSRC_NORMAL_IO; 334 } 335 336 enable_them: 337 /* ok dude, we got it, everybody conflicting has been disabled, let's 338 * enable us. Mark any bits in "owns" regardless of whether we 339 * decoded them. We can lock resources we don't decode, therefore 340 * we must track them via "owns". 341 */ 342 flags = 0; 343 pci_bits = 0; 344 345 if (!vgadev->bridge_has_one_vga) { 346 flags |= PCI_VGA_STATE_CHANGE_DECODES; 347 if (wants & (VGA_RSRC_LEGACY_MEM|VGA_RSRC_NORMAL_MEM)) 348 pci_bits |= PCI_COMMAND_MEMORY; 349 if (wants & (VGA_RSRC_LEGACY_IO|VGA_RSRC_NORMAL_IO)) 350 pci_bits |= PCI_COMMAND_IO; 351 } 352 if (wants & VGA_RSRC_LEGACY_MASK) 353 flags |= PCI_VGA_STATE_CHANGE_BRIDGE; 354 355 pci_set_vga_state(vgadev->pdev, true, pci_bits, flags); 356 357 vgadev->owns |= wants; 358 lock_them: 359 vgadev->locks |= (rsrc & VGA_RSRC_LEGACY_MASK); 360 if (rsrc & VGA_RSRC_LEGACY_IO) 361 vgadev->io_lock_cnt++; 362 if (rsrc & VGA_RSRC_LEGACY_MEM) 363 vgadev->mem_lock_cnt++; 364 if (rsrc & VGA_RSRC_NORMAL_IO) 365 vgadev->io_norm_cnt++; 366 if (rsrc & VGA_RSRC_NORMAL_MEM) 367 vgadev->mem_norm_cnt++; 368 369 return NULL; 370 } 371 372 static void __vga_put(struct vga_device *vgadev, unsigned int rsrc) 373 { 374 struct device *dev = &vgadev->pdev->dev; 375 unsigned int old_locks = vgadev->locks; 376 377 vgaarb_dbg(dev, "%s\n", __func__); 378 379 /* Update our counters, and account for equivalent legacy resources 380 * if we decode them 381 */ 382 if ((rsrc & VGA_RSRC_NORMAL_IO) && vgadev->io_norm_cnt > 0) { 383 vgadev->io_norm_cnt--; 384 if (vgadev->decodes & VGA_RSRC_LEGACY_IO) 385 rsrc |= VGA_RSRC_LEGACY_IO; 386 } 387 if ((rsrc & VGA_RSRC_NORMAL_MEM) && vgadev->mem_norm_cnt > 0) { 388 vgadev->mem_norm_cnt--; 389 if (vgadev->decodes & VGA_RSRC_LEGACY_MEM) 390 rsrc |= VGA_RSRC_LEGACY_MEM; 391 } 392 if ((rsrc & VGA_RSRC_LEGACY_IO) && vgadev->io_lock_cnt > 0) 393 vgadev->io_lock_cnt--; 394 if ((rsrc & VGA_RSRC_LEGACY_MEM) && vgadev->mem_lock_cnt > 0) 395 vgadev->mem_lock_cnt--; 396 397 /* Just clear lock bits, we do lazy operations so we don't really 398 * have to bother about anything else at this point 399 */ 400 if (vgadev->io_lock_cnt == 0) 401 vgadev->locks &= ~VGA_RSRC_LEGACY_IO; 402 if (vgadev->mem_lock_cnt == 0) 403 vgadev->locks &= ~VGA_RSRC_LEGACY_MEM; 404 405 /* Kick the wait queue in case somebody was waiting if we actually 406 * released something 407 */ 408 if (old_locks != vgadev->locks) 409 wake_up_all(&vga_wait_queue); 410 } 411 412 /** 413 * vga_get - acquire & locks VGA resources 414 * @pdev: pci device of the VGA card or NULL for the system default 415 * @rsrc: bit mask of resources to acquire and lock 416 * @interruptible: blocking should be interruptible by signals ? 417 * 418 * This function acquires VGA resources for the given card and mark those 419 * resources locked. If the resource requested are "normal" (and not legacy) 420 * resources, the arbiter will first check whether the card is doing legacy 421 * decoding for that type of resource. If yes, the lock is "converted" into a 422 * legacy resource lock. 423 * 424 * The arbiter will first look for all VGA cards that might conflict and disable 425 * their IOs and/or Memory access, including VGA forwarding on P2P bridges if 426 * necessary, so that the requested resources can be used. Then, the card is 427 * marked as locking these resources and the IO and/or Memory accesses are 428 * enabled on the card (including VGA forwarding on parent P2P bridges if any). 429 * 430 * This function will block if some conflicting card is already locking one of 431 * the required resources (or any resource on a different bus segment, since P2P 432 * bridges don't differentiate VGA memory and IO afaik). You can indicate 433 * whether this blocking should be interruptible by a signal (for userland 434 * interface) or not. 435 * 436 * Must not be called at interrupt time or in atomic context. If the card 437 * already owns the resources, the function succeeds. Nested calls are 438 * supported (a per-resource counter is maintained) 439 * 440 * On success, release the VGA resource again with vga_put(). 441 * 442 * Returns: 443 * 444 * 0 on success, negative error code on failure. 445 */ 446 int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible) 447 { 448 struct vga_device *vgadev, *conflict; 449 unsigned long flags; 450 wait_queue_entry_t wait; 451 int rc = 0; 452 453 vga_check_first_use(); 454 /* The one who calls us should check for this, but lets be sure... */ 455 if (pdev == NULL) 456 pdev = vga_default_device(); 457 if (pdev == NULL) 458 return 0; 459 460 for (;;) { 461 spin_lock_irqsave(&vga_lock, flags); 462 vgadev = vgadev_find(pdev); 463 if (vgadev == NULL) { 464 spin_unlock_irqrestore(&vga_lock, flags); 465 rc = -ENODEV; 466 break; 467 } 468 conflict = __vga_tryget(vgadev, rsrc); 469 spin_unlock_irqrestore(&vga_lock, flags); 470 if (conflict == NULL) 471 break; 472 473 474 /* We have a conflict, we wait until somebody kicks the 475 * work queue. Currently we have one work queue that we 476 * kick each time some resources are released, but it would 477 * be fairly easy to have a per device one so that we only 478 * need to attach to the conflicting device 479 */ 480 init_waitqueue_entry(&wait, current); 481 add_wait_queue(&vga_wait_queue, &wait); 482 set_current_state(interruptible ? 483 TASK_INTERRUPTIBLE : 484 TASK_UNINTERRUPTIBLE); 485 if (interruptible && signal_pending(current)) { 486 __set_current_state(TASK_RUNNING); 487 remove_wait_queue(&vga_wait_queue, &wait); 488 rc = -ERESTARTSYS; 489 break; 490 } 491 schedule(); 492 remove_wait_queue(&vga_wait_queue, &wait); 493 } 494 return rc; 495 } 496 EXPORT_SYMBOL(vga_get); 497 498 /** 499 * vga_tryget - try to acquire & lock legacy VGA resources 500 * @pdev: pci devivce of VGA card or NULL for system default 501 * @rsrc: bit mask of resources to acquire and lock 502 * 503 * This function performs the same operation as vga_get(), but will return an 504 * error (-EBUSY) instead of blocking if the resources are already locked by 505 * another card. It can be called in any context 506 * 507 * On success, release the VGA resource again with vga_put(). 508 * 509 * Returns: 510 * 511 * 0 on success, negative error code on failure. 512 */ 513 static int vga_tryget(struct pci_dev *pdev, unsigned int rsrc) 514 { 515 struct vga_device *vgadev; 516 unsigned long flags; 517 int rc = 0; 518 519 vga_check_first_use(); 520 521 /* The one who calls us should check for this, but lets be sure... */ 522 if (pdev == NULL) 523 pdev = vga_default_device(); 524 if (pdev == NULL) 525 return 0; 526 spin_lock_irqsave(&vga_lock, flags); 527 vgadev = vgadev_find(pdev); 528 if (vgadev == NULL) { 529 rc = -ENODEV; 530 goto bail; 531 } 532 if (__vga_tryget(vgadev, rsrc)) 533 rc = -EBUSY; 534 bail: 535 spin_unlock_irqrestore(&vga_lock, flags); 536 return rc; 537 } 538 539 /** 540 * vga_put - release lock on legacy VGA resources 541 * @pdev: pci device of VGA card or NULL for system default 542 * @rsrc: but mask of resource to release 543 * 544 * This fuction releases resources previously locked by vga_get() or 545 * vga_tryget(). The resources aren't disabled right away, so that a subsequence 546 * vga_get() on the same card will succeed immediately. Resources have a 547 * counter, so locks are only released if the counter reaches 0. 548 */ 549 void vga_put(struct pci_dev *pdev, unsigned int rsrc) 550 { 551 struct vga_device *vgadev; 552 unsigned long flags; 553 554 /* The one who calls us should check for this, but lets be sure... */ 555 if (pdev == NULL) 556 pdev = vga_default_device(); 557 if (pdev == NULL) 558 return; 559 spin_lock_irqsave(&vga_lock, flags); 560 vgadev = vgadev_find(pdev); 561 if (vgadev == NULL) 562 goto bail; 563 __vga_put(vgadev, rsrc); 564 bail: 565 spin_unlock_irqrestore(&vga_lock, flags); 566 } 567 EXPORT_SYMBOL(vga_put); 568 569 static bool vga_is_firmware_default(struct pci_dev *pdev) 570 { 571 #if defined(CONFIG_X86) || defined(CONFIG_IA64) 572 u64 base = screen_info.lfb_base; 573 u64 size = screen_info.lfb_size; 574 u64 limit; 575 resource_size_t start, end; 576 unsigned long flags; 577 int i; 578 579 /* Select the device owning the boot framebuffer if there is one */ 580 581 if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) 582 base |= (u64)screen_info.ext_lfb_base << 32; 583 584 limit = base + size; 585 586 /* Does firmware framebuffer belong to us? */ 587 for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) { 588 flags = pci_resource_flags(pdev, i); 589 590 if ((flags & IORESOURCE_MEM) == 0) 591 continue; 592 593 start = pci_resource_start(pdev, i); 594 end = pci_resource_end(pdev, i); 595 596 if (!start || !end) 597 continue; 598 599 if (base < start || limit >= end) 600 continue; 601 602 return true; 603 } 604 #endif 605 return false; 606 } 607 608 static bool vga_arb_integrated_gpu(struct device *dev) 609 { 610 #if defined(CONFIG_ACPI) 611 struct acpi_device *adev = ACPI_COMPANION(dev); 612 613 return adev && !strcmp(acpi_device_hid(adev), ACPI_VIDEO_HID); 614 #else 615 return false; 616 #endif 617 } 618 619 /* 620 * Return true if vgadev is a better default VGA device than the best one 621 * we've seen so far. 622 */ 623 static bool vga_is_boot_device(struct vga_device *vgadev) 624 { 625 struct vga_device *boot_vga = vgadev_find(vga_default_device()); 626 struct pci_dev *pdev = vgadev->pdev; 627 u16 cmd, boot_cmd; 628 629 /* 630 * We select the default VGA device in this order: 631 * Firmware framebuffer (see vga_arb_select_default_device()) 632 * Legacy VGA device (owns VGA_RSRC_LEGACY_MASK) 633 * Non-legacy integrated device (see vga_arb_select_default_device()) 634 * Non-legacy discrete device (see vga_arb_select_default_device()) 635 * Other device (see vga_arb_select_default_device()) 636 */ 637 638 /* 639 * We always prefer a firmware default device, so if we've already 640 * found one, there's no need to consider vgadev. 641 */ 642 if (boot_vga && boot_vga->is_firmware_default) 643 return false; 644 645 if (vga_is_firmware_default(pdev)) { 646 vgadev->is_firmware_default = true; 647 return true; 648 } 649 650 /* 651 * A legacy VGA device has MEM and IO enabled and any bridges 652 * leading to it have PCI_BRIDGE_CTL_VGA enabled so the legacy 653 * resources ([mem 0xa0000-0xbffff], [io 0x3b0-0x3bb], etc) are 654 * routed to it. 655 * 656 * We use the first one we find, so if we've already found one, 657 * vgadev is no better. 658 */ 659 if (boot_vga && 660 (boot_vga->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK) 661 return false; 662 663 if ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK) 664 return true; 665 666 /* 667 * If we haven't found a legacy VGA device, accept a non-legacy 668 * device. It may have either IO or MEM enabled, and bridges may 669 * not have PCI_BRIDGE_CTL_VGA enabled, so it may not be able to 670 * use legacy VGA resources. Prefer an integrated GPU over others. 671 */ 672 pci_read_config_word(pdev, PCI_COMMAND, &cmd); 673 if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) { 674 675 /* 676 * An integrated GPU overrides a previous non-legacy 677 * device. We expect only a single integrated GPU, but if 678 * there are more, we use the *last* because that was the 679 * previous behavior. 680 */ 681 if (vga_arb_integrated_gpu(&pdev->dev)) 682 return true; 683 684 /* 685 * We prefer the first non-legacy discrete device we find. 686 * If we already found one, vgadev is no better. 687 */ 688 if (boot_vga) { 689 pci_read_config_word(boot_vga->pdev, PCI_COMMAND, 690 &boot_cmd); 691 if (boot_cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) 692 return false; 693 } 694 return true; 695 } 696 697 /* 698 * vgadev has neither IO nor MEM enabled. If we haven't found any 699 * other VGA devices, it is the best candidate so far. 700 */ 701 if (!boot_vga) 702 return true; 703 704 return false; 705 } 706 707 /* 708 * Rules for using a bridge to control a VGA descendant decoding: if a bridge 709 * has only one VGA descendant then it can be used to control the VGA routing 710 * for that device. It should always use the bridge closest to the device to 711 * control it. If a bridge has a direct VGA descendant, but also have a sub- 712 * bridge VGA descendant then we cannot use that bridge to control the direct 713 * VGA descendant. So for every device we register, we need to iterate all 714 * its parent bridges so we can invalidate any devices using them properly. 715 */ 716 static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev) 717 { 718 struct vga_device *same_bridge_vgadev; 719 struct pci_bus *new_bus, *bus; 720 struct pci_dev *new_bridge, *bridge; 721 722 vgadev->bridge_has_one_vga = true; 723 724 if (list_empty(&vga_list)) 725 return; 726 727 /* okay iterate the new devices bridge hierarachy */ 728 new_bus = vgadev->pdev->bus; 729 while (new_bus) { 730 new_bridge = new_bus->self; 731 732 /* go through list of devices already registered */ 733 list_for_each_entry(same_bridge_vgadev, &vga_list, list) { 734 bus = same_bridge_vgadev->pdev->bus; 735 bridge = bus->self; 736 737 /* see if the share a bridge with this device */ 738 if (new_bridge == bridge) { 739 /* 740 * If their direct parent bridge is the same 741 * as any bridge of this device then it can't 742 * be used for that device. 743 */ 744 same_bridge_vgadev->bridge_has_one_vga = false; 745 } 746 747 /* 748 * Now iterate the previous devices bridge hierarchy. 749 * If the new devices parent bridge is in the other 750 * devices hierarchy then we can't use it to control 751 * this device 752 */ 753 while (bus) { 754 bridge = bus->self; 755 756 if (bridge && bridge == vgadev->pdev->bus->self) 757 vgadev->bridge_has_one_vga = false; 758 759 bus = bus->parent; 760 } 761 } 762 new_bus = new_bus->parent; 763 } 764 } 765 766 /* 767 * Currently, we assume that the "initial" setup of the system is 768 * not sane, that is we come up with conflicting devices and let 769 * the arbiter's client decides if devices decodes or not legacy 770 * things. 771 */ 772 static bool vga_arbiter_add_pci_device(struct pci_dev *pdev) 773 { 774 struct vga_device *vgadev; 775 unsigned long flags; 776 struct pci_bus *bus; 777 struct pci_dev *bridge; 778 u16 cmd; 779 780 /* Only deal with VGA class devices */ 781 if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA) 782 return false; 783 784 /* Allocate structure */ 785 vgadev = kzalloc(sizeof(struct vga_device), GFP_KERNEL); 786 if (vgadev == NULL) { 787 vgaarb_err(&pdev->dev, "failed to allocate VGA arbiter data\n"); 788 /* 789 * What to do on allocation failure ? For now, let's just do 790 * nothing, I'm not sure there is anything saner to be done. 791 */ 792 return false; 793 } 794 795 /* Take lock & check for duplicates */ 796 spin_lock_irqsave(&vga_lock, flags); 797 if (vgadev_find(pdev) != NULL) { 798 BUG_ON(1); 799 goto fail; 800 } 801 vgadev->pdev = pdev; 802 803 /* By default, assume we decode everything */ 804 vgadev->decodes = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM | 805 VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM; 806 807 /* by default mark it as decoding */ 808 vga_decode_count++; 809 /* Mark that we "own" resources based on our enables, we will 810 * clear that below if the bridge isn't forwarding 811 */ 812 pci_read_config_word(pdev, PCI_COMMAND, &cmd); 813 if (cmd & PCI_COMMAND_IO) 814 vgadev->owns |= VGA_RSRC_LEGACY_IO; 815 if (cmd & PCI_COMMAND_MEMORY) 816 vgadev->owns |= VGA_RSRC_LEGACY_MEM; 817 818 /* Check if VGA cycles can get down to us */ 819 bus = pdev->bus; 820 while (bus) { 821 bridge = bus->self; 822 if (bridge) { 823 u16 l; 824 825 pci_read_config_word(bridge, PCI_BRIDGE_CONTROL, &l); 826 if (!(l & PCI_BRIDGE_CTL_VGA)) { 827 vgadev->owns = 0; 828 break; 829 } 830 } 831 bus = bus->parent; 832 } 833 834 if (vga_is_boot_device(vgadev)) { 835 vgaarb_info(&pdev->dev, "setting as boot VGA device%s\n", 836 vga_default_device() ? 837 " (overriding previous)" : ""); 838 vga_set_default_device(pdev); 839 } 840 841 vga_arbiter_check_bridge_sharing(vgadev); 842 843 /* Add to the list */ 844 list_add_tail(&vgadev->list, &vga_list); 845 vga_count++; 846 vgaarb_info(&pdev->dev, "VGA device added: decodes=%s,owns=%s,locks=%s\n", 847 vga_iostate_to_str(vgadev->decodes), 848 vga_iostate_to_str(vgadev->owns), 849 vga_iostate_to_str(vgadev->locks)); 850 851 spin_unlock_irqrestore(&vga_lock, flags); 852 return true; 853 fail: 854 spin_unlock_irqrestore(&vga_lock, flags); 855 kfree(vgadev); 856 return false; 857 } 858 859 static bool vga_arbiter_del_pci_device(struct pci_dev *pdev) 860 { 861 struct vga_device *vgadev; 862 unsigned long flags; 863 bool ret = true; 864 865 spin_lock_irqsave(&vga_lock, flags); 866 vgadev = vgadev_find(pdev); 867 if (vgadev == NULL) { 868 ret = false; 869 goto bail; 870 } 871 872 if (vga_default == pdev) 873 vga_set_default_device(NULL); 874 875 if (vgadev->decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM)) 876 vga_decode_count--; 877 878 /* Remove entry from list */ 879 list_del(&vgadev->list); 880 vga_count--; 881 /* Notify userland driver that the device is gone so it discards 882 * it's copies of the pci_dev pointer 883 */ 884 vga_arb_device_card_gone(pdev); 885 886 /* Wake up all possible waiters */ 887 wake_up_all(&vga_wait_queue); 888 bail: 889 spin_unlock_irqrestore(&vga_lock, flags); 890 kfree(vgadev); 891 return ret; 892 } 893 894 /* this is called with the lock */ 895 static inline void vga_update_device_decodes(struct vga_device *vgadev, 896 int new_decodes) 897 { 898 struct device *dev = &vgadev->pdev->dev; 899 int old_decodes, decodes_removed, decodes_unlocked; 900 901 old_decodes = vgadev->decodes; 902 decodes_removed = ~new_decodes & old_decodes; 903 decodes_unlocked = vgadev->locks & decodes_removed; 904 vgadev->decodes = new_decodes; 905 906 vgaarb_info(dev, "changed VGA decodes: olddecodes=%s,decodes=%s:owns=%s\n", 907 vga_iostate_to_str(old_decodes), 908 vga_iostate_to_str(vgadev->decodes), 909 vga_iostate_to_str(vgadev->owns)); 910 911 /* if we removed locked decodes, lock count goes to zero, and release */ 912 if (decodes_unlocked) { 913 if (decodes_unlocked & VGA_RSRC_LEGACY_IO) 914 vgadev->io_lock_cnt = 0; 915 if (decodes_unlocked & VGA_RSRC_LEGACY_MEM) 916 vgadev->mem_lock_cnt = 0; 917 __vga_put(vgadev, decodes_unlocked); 918 } 919 920 /* change decodes counter */ 921 if (old_decodes & VGA_RSRC_LEGACY_MASK && 922 !(new_decodes & VGA_RSRC_LEGACY_MASK)) 923 vga_decode_count--; 924 if (!(old_decodes & VGA_RSRC_LEGACY_MASK) && 925 new_decodes & VGA_RSRC_LEGACY_MASK) 926 vga_decode_count++; 927 vgaarb_dbg(dev, "decoding count now is: %d\n", vga_decode_count); 928 } 929 930 static void __vga_set_legacy_decoding(struct pci_dev *pdev, 931 unsigned int decodes, 932 bool userspace) 933 { 934 struct vga_device *vgadev; 935 unsigned long flags; 936 937 decodes &= VGA_RSRC_LEGACY_MASK; 938 939 spin_lock_irqsave(&vga_lock, flags); 940 vgadev = vgadev_find(pdev); 941 if (vgadev == NULL) 942 goto bail; 943 944 /* don't let userspace futz with kernel driver decodes */ 945 if (userspace && vgadev->set_decode) 946 goto bail; 947 948 /* update the device decodes + counter */ 949 vga_update_device_decodes(vgadev, decodes); 950 951 /* XXX if somebody is going from "doesn't decode" to "decodes" state 952 * here, additional care must be taken as we may have pending owner 953 * ship of non-legacy region ... 954 */ 955 bail: 956 spin_unlock_irqrestore(&vga_lock, flags); 957 } 958 959 /** 960 * vga_set_legacy_decoding 961 * @pdev: pci device of the VGA card 962 * @decodes: bit mask of what legacy regions the card decodes 963 * 964 * Indicates to the arbiter if the card decodes legacy VGA IOs, legacy VGA 965 * Memory, both, or none. All cards default to both, the card driver (fbdev for 966 * example) should tell the arbiter if it has disabled legacy decoding, so the 967 * card can be left out of the arbitration process (and can be safe to take 968 * interrupts at any time. 969 */ 970 void vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes) 971 { 972 __vga_set_legacy_decoding(pdev, decodes, false); 973 } 974 EXPORT_SYMBOL(vga_set_legacy_decoding); 975 976 /** 977 * vga_client_register - register or unregister a VGA arbitration client 978 * @pdev: pci device of the VGA client 979 * @set_decode: vga decode change callback 980 * 981 * Clients have two callback mechanisms they can use. 982 * 983 * @set_decode callback: If a client can disable its GPU VGA resource, it 984 * will get a callback from this to set the encode/decode state. 985 * 986 * Rationale: we cannot disable VGA decode resources unconditionally some single 987 * GPU laptops seem to require ACPI or BIOS access to the VGA registers to 988 * control things like backlights etc. Hopefully newer multi-GPU laptops do 989 * something saner, and desktops won't have any special ACPI for this. The 990 * driver will get a callback when VGA arbitration is first used by userspace 991 * since some older X servers have issues. 992 * 993 * This function does not check whether a client for @pdev has been registered 994 * already. 995 * 996 * To unregister just call vga_client_unregister(). 997 * 998 * Returns: 0 on success, -1 on failure 999 */ 1000 int vga_client_register(struct pci_dev *pdev, 1001 unsigned int (*set_decode)(struct pci_dev *pdev, bool decode)) 1002 { 1003 int ret = -ENODEV; 1004 struct vga_device *vgadev; 1005 unsigned long flags; 1006 1007 spin_lock_irqsave(&vga_lock, flags); 1008 vgadev = vgadev_find(pdev); 1009 if (!vgadev) 1010 goto bail; 1011 1012 vgadev->set_decode = set_decode; 1013 ret = 0; 1014 1015 bail: 1016 spin_unlock_irqrestore(&vga_lock, flags); 1017 return ret; 1018 1019 } 1020 EXPORT_SYMBOL(vga_client_register); 1021 1022 /* 1023 * Char driver implementation 1024 * 1025 * Semantics is: 1026 * 1027 * open : open user instance of the arbitrer. by default, it's 1028 * attached to the default VGA device of the system. 1029 * 1030 * close : close user instance, release locks 1031 * 1032 * read : return a string indicating the status of the target. 1033 * an IO state string is of the form {io,mem,io+mem,none}, 1034 * mc and ic are respectively mem and io lock counts (for 1035 * debugging/diagnostic only). "decodes" indicate what the 1036 * card currently decodes, "owns" indicates what is currently 1037 * enabled on it, and "locks" indicates what is locked by this 1038 * card. If the card is unplugged, we get "invalid" then for 1039 * card_ID and an -ENODEV error is returned for any command 1040 * until a new card is targeted 1041 * 1042 * "<card_ID>,decodes=<io_state>,owns=<io_state>,locks=<io_state> (ic,mc)" 1043 * 1044 * write : write a command to the arbiter. List of commands is: 1045 * 1046 * target <card_ID> : switch target to card <card_ID> (see below) 1047 * lock <io_state> : acquires locks on target ("none" is invalid io_state) 1048 * trylock <io_state> : non-blocking acquire locks on target 1049 * unlock <io_state> : release locks on target 1050 * unlock all : release all locks on target held by this user 1051 * decodes <io_state> : set the legacy decoding attributes for the card 1052 * 1053 * poll : event if something change on any card (not just the target) 1054 * 1055 * card_ID is of the form "PCI:domain:bus:dev.fn". It can be set to "default" 1056 * to go back to the system default card (TODO: not implemented yet). 1057 * Currently, only PCI is supported as a prefix, but the userland API may 1058 * support other bus types in the future, even if the current kernel 1059 * implementation doesn't. 1060 * 1061 * Note about locks: 1062 * 1063 * The driver keeps track of which user has what locks on which card. It 1064 * supports stacking, like the kernel one. This complexifies the implementation 1065 * a bit, but makes the arbiter more tolerant to userspace problems and able 1066 * to properly cleanup in all cases when a process dies. 1067 * Currently, a max of 16 cards simultaneously can have locks issued from 1068 * userspace for a given user (file descriptor instance) of the arbiter. 1069 * 1070 * If the device is hot-unplugged, there is a hook inside the module to notify 1071 * they being added/removed in the system and automatically added/removed in 1072 * the arbiter. 1073 */ 1074 1075 #define MAX_USER_CARDS CONFIG_VGA_ARB_MAX_GPUS 1076 #define PCI_INVALID_CARD ((struct pci_dev *)-1UL) 1077 1078 /* 1079 * Each user has an array of these, tracking which cards have locks 1080 */ 1081 struct vga_arb_user_card { 1082 struct pci_dev *pdev; 1083 unsigned int mem_cnt; 1084 unsigned int io_cnt; 1085 }; 1086 1087 struct vga_arb_private { 1088 struct list_head list; 1089 struct pci_dev *target; 1090 struct vga_arb_user_card cards[MAX_USER_CARDS]; 1091 spinlock_t lock; 1092 }; 1093 1094 static LIST_HEAD(vga_user_list); 1095 static DEFINE_SPINLOCK(vga_user_lock); 1096 1097 1098 /* 1099 * This function gets a string in the format: "PCI:domain:bus:dev.fn" and 1100 * returns the respective values. If the string is not in this format, 1101 * it returns 0. 1102 */ 1103 static int vga_pci_str_to_vars(char *buf, int count, unsigned int *domain, 1104 unsigned int *bus, unsigned int *devfn) 1105 { 1106 int n; 1107 unsigned int slot, func; 1108 1109 1110 n = sscanf(buf, "PCI:%x:%x:%x.%x", domain, bus, &slot, &func); 1111 if (n != 4) 1112 return 0; 1113 1114 *devfn = PCI_DEVFN(slot, func); 1115 1116 return 1; 1117 } 1118 1119 static ssize_t vga_arb_read(struct file *file, char __user *buf, 1120 size_t count, loff_t *ppos) 1121 { 1122 struct vga_arb_private *priv = file->private_data; 1123 struct vga_device *vgadev; 1124 struct pci_dev *pdev; 1125 unsigned long flags; 1126 size_t len; 1127 int rc; 1128 char *lbuf; 1129 1130 lbuf = kmalloc(1024, GFP_KERNEL); 1131 if (lbuf == NULL) 1132 return -ENOMEM; 1133 1134 /* Shields against vga_arb_device_card_gone (pci_dev going 1135 * away), and allows access to vga list 1136 */ 1137 spin_lock_irqsave(&vga_lock, flags); 1138 1139 /* If we are targeting the default, use it */ 1140 pdev = priv->target; 1141 if (pdev == NULL || pdev == PCI_INVALID_CARD) { 1142 spin_unlock_irqrestore(&vga_lock, flags); 1143 len = sprintf(lbuf, "invalid"); 1144 goto done; 1145 } 1146 1147 /* Find card vgadev structure */ 1148 vgadev = vgadev_find(pdev); 1149 if (vgadev == NULL) { 1150 /* Wow, it's not in the list, that shouldn't happen, 1151 * let's fix us up and return invalid card 1152 */ 1153 if (pdev == priv->target) 1154 vga_arb_device_card_gone(pdev); 1155 spin_unlock_irqrestore(&vga_lock, flags); 1156 len = sprintf(lbuf, "invalid"); 1157 goto done; 1158 } 1159 1160 /* Fill the buffer with infos */ 1161 len = snprintf(lbuf, 1024, 1162 "count:%d,PCI:%s,decodes=%s,owns=%s,locks=%s(%d:%d)\n", 1163 vga_decode_count, pci_name(pdev), 1164 vga_iostate_to_str(vgadev->decodes), 1165 vga_iostate_to_str(vgadev->owns), 1166 vga_iostate_to_str(vgadev->locks), 1167 vgadev->io_lock_cnt, vgadev->mem_lock_cnt); 1168 1169 spin_unlock_irqrestore(&vga_lock, flags); 1170 done: 1171 1172 /* Copy that to user */ 1173 if (len > count) 1174 len = count; 1175 rc = copy_to_user(buf, lbuf, len); 1176 kfree(lbuf); 1177 if (rc) 1178 return -EFAULT; 1179 return len; 1180 } 1181 1182 /* 1183 * TODO: To avoid parsing inside kernel and to improve the speed we may 1184 * consider use ioctl here 1185 */ 1186 static ssize_t vga_arb_write(struct file *file, const char __user *buf, 1187 size_t count, loff_t *ppos) 1188 { 1189 struct vga_arb_private *priv = file->private_data; 1190 struct vga_arb_user_card *uc = NULL; 1191 struct pci_dev *pdev; 1192 1193 unsigned int io_state; 1194 1195 char kbuf[64], *curr_pos; 1196 size_t remaining = count; 1197 1198 int ret_val; 1199 int i; 1200 1201 if (count >= sizeof(kbuf)) 1202 return -EINVAL; 1203 if (copy_from_user(kbuf, buf, count)) 1204 return -EFAULT; 1205 curr_pos = kbuf; 1206 kbuf[count] = '\0'; /* Just to make sure... */ 1207 1208 if (strncmp(curr_pos, "lock ", 5) == 0) { 1209 curr_pos += 5; 1210 remaining -= 5; 1211 1212 pr_debug("client 0x%p called 'lock'\n", priv); 1213 1214 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { 1215 ret_val = -EPROTO; 1216 goto done; 1217 } 1218 if (io_state == VGA_RSRC_NONE) { 1219 ret_val = -EPROTO; 1220 goto done; 1221 } 1222 1223 pdev = priv->target; 1224 if (priv->target == NULL) { 1225 ret_val = -ENODEV; 1226 goto done; 1227 } 1228 1229 vga_get_uninterruptible(pdev, io_state); 1230 1231 /* Update the client's locks lists... */ 1232 for (i = 0; i < MAX_USER_CARDS; i++) { 1233 if (priv->cards[i].pdev == pdev) { 1234 if (io_state & VGA_RSRC_LEGACY_IO) 1235 priv->cards[i].io_cnt++; 1236 if (io_state & VGA_RSRC_LEGACY_MEM) 1237 priv->cards[i].mem_cnt++; 1238 break; 1239 } 1240 } 1241 1242 ret_val = count; 1243 goto done; 1244 } else if (strncmp(curr_pos, "unlock ", 7) == 0) { 1245 curr_pos += 7; 1246 remaining -= 7; 1247 1248 pr_debug("client 0x%p called 'unlock'\n", priv); 1249 1250 if (strncmp(curr_pos, "all", 3) == 0) 1251 io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; 1252 else { 1253 if (!vga_str_to_iostate 1254 (curr_pos, remaining, &io_state)) { 1255 ret_val = -EPROTO; 1256 goto done; 1257 } 1258 /* TODO: Add this? 1259 if (io_state == VGA_RSRC_NONE) { 1260 ret_val = -EPROTO; 1261 goto done; 1262 } 1263 */ 1264 } 1265 1266 pdev = priv->target; 1267 if (priv->target == NULL) { 1268 ret_val = -ENODEV; 1269 goto done; 1270 } 1271 for (i = 0; i < MAX_USER_CARDS; i++) { 1272 if (priv->cards[i].pdev == pdev) 1273 uc = &priv->cards[i]; 1274 } 1275 1276 if (!uc) { 1277 ret_val = -EINVAL; 1278 goto done; 1279 } 1280 1281 if (io_state & VGA_RSRC_LEGACY_IO && uc->io_cnt == 0) { 1282 ret_val = -EINVAL; 1283 goto done; 1284 } 1285 1286 if (io_state & VGA_RSRC_LEGACY_MEM && uc->mem_cnt == 0) { 1287 ret_val = -EINVAL; 1288 goto done; 1289 } 1290 1291 vga_put(pdev, io_state); 1292 1293 if (io_state & VGA_RSRC_LEGACY_IO) 1294 uc->io_cnt--; 1295 if (io_state & VGA_RSRC_LEGACY_MEM) 1296 uc->mem_cnt--; 1297 1298 ret_val = count; 1299 goto done; 1300 } else if (strncmp(curr_pos, "trylock ", 8) == 0) { 1301 curr_pos += 8; 1302 remaining -= 8; 1303 1304 pr_debug("client 0x%p called 'trylock'\n", priv); 1305 1306 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { 1307 ret_val = -EPROTO; 1308 goto done; 1309 } 1310 /* TODO: Add this? 1311 if (io_state == VGA_RSRC_NONE) { 1312 ret_val = -EPROTO; 1313 goto done; 1314 } 1315 */ 1316 1317 pdev = priv->target; 1318 if (priv->target == NULL) { 1319 ret_val = -ENODEV; 1320 goto done; 1321 } 1322 1323 if (vga_tryget(pdev, io_state)) { 1324 /* Update the client's locks lists... */ 1325 for (i = 0; i < MAX_USER_CARDS; i++) { 1326 if (priv->cards[i].pdev == pdev) { 1327 if (io_state & VGA_RSRC_LEGACY_IO) 1328 priv->cards[i].io_cnt++; 1329 if (io_state & VGA_RSRC_LEGACY_MEM) 1330 priv->cards[i].mem_cnt++; 1331 break; 1332 } 1333 } 1334 ret_val = count; 1335 goto done; 1336 } else { 1337 ret_val = -EBUSY; 1338 goto done; 1339 } 1340 1341 } else if (strncmp(curr_pos, "target ", 7) == 0) { 1342 unsigned int domain, bus, devfn; 1343 struct vga_device *vgadev; 1344 1345 curr_pos += 7; 1346 remaining -= 7; 1347 pr_debug("client 0x%p called 'target'\n", priv); 1348 /* if target is default */ 1349 if (!strncmp(curr_pos, "default", 7)) 1350 pdev = pci_dev_get(vga_default_device()); 1351 else { 1352 if (!vga_pci_str_to_vars(curr_pos, remaining, 1353 &domain, &bus, &devfn)) { 1354 ret_val = -EPROTO; 1355 goto done; 1356 } 1357 pdev = pci_get_domain_bus_and_slot(domain, bus, devfn); 1358 if (!pdev) { 1359 pr_debug("invalid PCI address %04x:%02x:%02x.%x\n", 1360 domain, bus, PCI_SLOT(devfn), 1361 PCI_FUNC(devfn)); 1362 ret_val = -ENODEV; 1363 goto done; 1364 } 1365 1366 pr_debug("%s ==> %04x:%02x:%02x.%x pdev %p\n", curr_pos, 1367 domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn), 1368 pdev); 1369 } 1370 1371 vgadev = vgadev_find(pdev); 1372 pr_debug("vgadev %p\n", vgadev); 1373 if (vgadev == NULL) { 1374 if (pdev) { 1375 vgaarb_dbg(&pdev->dev, "not a VGA device\n"); 1376 pci_dev_put(pdev); 1377 } 1378 1379 ret_val = -ENODEV; 1380 goto done; 1381 } 1382 1383 priv->target = pdev; 1384 for (i = 0; i < MAX_USER_CARDS; i++) { 1385 if (priv->cards[i].pdev == pdev) 1386 break; 1387 if (priv->cards[i].pdev == NULL) { 1388 priv->cards[i].pdev = pdev; 1389 priv->cards[i].io_cnt = 0; 1390 priv->cards[i].mem_cnt = 0; 1391 break; 1392 } 1393 } 1394 if (i == MAX_USER_CARDS) { 1395 vgaarb_dbg(&pdev->dev, "maximum user cards (%d) number reached, ignoring this one!\n", 1396 MAX_USER_CARDS); 1397 pci_dev_put(pdev); 1398 /* XXX: which value to return? */ 1399 ret_val = -ENOMEM; 1400 goto done; 1401 } 1402 1403 ret_val = count; 1404 pci_dev_put(pdev); 1405 goto done; 1406 1407 1408 } else if (strncmp(curr_pos, "decodes ", 8) == 0) { 1409 curr_pos += 8; 1410 remaining -= 8; 1411 pr_debug("client 0x%p called 'decodes'\n", priv); 1412 1413 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { 1414 ret_val = -EPROTO; 1415 goto done; 1416 } 1417 pdev = priv->target; 1418 if (priv->target == NULL) { 1419 ret_val = -ENODEV; 1420 goto done; 1421 } 1422 1423 __vga_set_legacy_decoding(pdev, io_state, true); 1424 ret_val = count; 1425 goto done; 1426 } 1427 /* If we got here, the message written is not part of the protocol! */ 1428 return -EPROTO; 1429 1430 done: 1431 return ret_val; 1432 } 1433 1434 static __poll_t vga_arb_fpoll(struct file *file, poll_table *wait) 1435 { 1436 pr_debug("%s\n", __func__); 1437 1438 poll_wait(file, &vga_wait_queue, wait); 1439 return EPOLLIN; 1440 } 1441 1442 static int vga_arb_open(struct inode *inode, struct file *file) 1443 { 1444 struct vga_arb_private *priv; 1445 unsigned long flags; 1446 1447 pr_debug("%s\n", __func__); 1448 1449 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 1450 if (priv == NULL) 1451 return -ENOMEM; 1452 spin_lock_init(&priv->lock); 1453 file->private_data = priv; 1454 1455 spin_lock_irqsave(&vga_user_lock, flags); 1456 list_add(&priv->list, &vga_user_list); 1457 spin_unlock_irqrestore(&vga_user_lock, flags); 1458 1459 /* Set the client' lists of locks */ 1460 priv->target = vga_default_device(); /* Maybe this is still null! */ 1461 priv->cards[0].pdev = priv->target; 1462 priv->cards[0].io_cnt = 0; 1463 priv->cards[0].mem_cnt = 0; 1464 1465 1466 return 0; 1467 } 1468 1469 static int vga_arb_release(struct inode *inode, struct file *file) 1470 { 1471 struct vga_arb_private *priv = file->private_data; 1472 struct vga_arb_user_card *uc; 1473 unsigned long flags; 1474 int i; 1475 1476 pr_debug("%s\n", __func__); 1477 1478 spin_lock_irqsave(&vga_user_lock, flags); 1479 list_del(&priv->list); 1480 for (i = 0; i < MAX_USER_CARDS; i++) { 1481 uc = &priv->cards[i]; 1482 if (uc->pdev == NULL) 1483 continue; 1484 vgaarb_dbg(&uc->pdev->dev, "uc->io_cnt == %d, uc->mem_cnt == %d\n", 1485 uc->io_cnt, uc->mem_cnt); 1486 while (uc->io_cnt--) 1487 vga_put(uc->pdev, VGA_RSRC_LEGACY_IO); 1488 while (uc->mem_cnt--) 1489 vga_put(uc->pdev, VGA_RSRC_LEGACY_MEM); 1490 } 1491 spin_unlock_irqrestore(&vga_user_lock, flags); 1492 1493 kfree(priv); 1494 1495 return 0; 1496 } 1497 1498 static void vga_arb_device_card_gone(struct pci_dev *pdev) 1499 { 1500 } 1501 1502 /* 1503 * callback any registered clients to let them know we have a 1504 * change in VGA cards 1505 */ 1506 static void vga_arbiter_notify_clients(void) 1507 { 1508 struct vga_device *vgadev; 1509 unsigned long flags; 1510 uint32_t new_decodes; 1511 bool new_state; 1512 1513 if (!vga_arbiter_used) 1514 return; 1515 1516 spin_lock_irqsave(&vga_lock, flags); 1517 list_for_each_entry(vgadev, &vga_list, list) { 1518 if (vga_count > 1) 1519 new_state = false; 1520 else 1521 new_state = true; 1522 if (vgadev->set_decode) { 1523 new_decodes = vgadev->set_decode(vgadev->pdev, 1524 new_state); 1525 vga_update_device_decodes(vgadev, new_decodes); 1526 } 1527 } 1528 spin_unlock_irqrestore(&vga_lock, flags); 1529 } 1530 1531 static int pci_notify(struct notifier_block *nb, unsigned long action, 1532 void *data) 1533 { 1534 struct device *dev = data; 1535 struct pci_dev *pdev = to_pci_dev(dev); 1536 bool notify = false; 1537 1538 vgaarb_dbg(dev, "%s\n", __func__); 1539 1540 /* For now we're only intereted in devices added and removed. I didn't 1541 * test this thing here, so someone needs to double check for the 1542 * cases of hotplugable vga cards. */ 1543 if (action == BUS_NOTIFY_ADD_DEVICE) 1544 notify = vga_arbiter_add_pci_device(pdev); 1545 else if (action == BUS_NOTIFY_DEL_DEVICE) 1546 notify = vga_arbiter_del_pci_device(pdev); 1547 1548 if (notify) 1549 vga_arbiter_notify_clients(); 1550 return 0; 1551 } 1552 1553 static struct notifier_block pci_notifier = { 1554 .notifier_call = pci_notify, 1555 }; 1556 1557 static const struct file_operations vga_arb_device_fops = { 1558 .read = vga_arb_read, 1559 .write = vga_arb_write, 1560 .poll = vga_arb_fpoll, 1561 .open = vga_arb_open, 1562 .release = vga_arb_release, 1563 .llseek = noop_llseek, 1564 }; 1565 1566 static struct miscdevice vga_arb_device = { 1567 MISC_DYNAMIC_MINOR, "vga_arbiter", &vga_arb_device_fops 1568 }; 1569 1570 static int __init vga_arb_device_init(void) 1571 { 1572 int rc; 1573 struct pci_dev *pdev; 1574 struct vga_device *vgadev; 1575 1576 rc = misc_register(&vga_arb_device); 1577 if (rc < 0) 1578 pr_err("error %d registering device\n", rc); 1579 1580 bus_register_notifier(&pci_bus_type, &pci_notifier); 1581 1582 /* We add all PCI devices satisfying VGA class in the arbiter by 1583 * default */ 1584 pdev = NULL; 1585 while ((pdev = 1586 pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, 1587 PCI_ANY_ID, pdev)) != NULL) 1588 vga_arbiter_add_pci_device(pdev); 1589 1590 list_for_each_entry(vgadev, &vga_list, list) { 1591 struct device *dev = &vgadev->pdev->dev; 1592 1593 if (vgadev->bridge_has_one_vga) 1594 vgaarb_info(dev, "bridge control possible\n"); 1595 else 1596 vgaarb_info(dev, "no bridge control possible\n"); 1597 } 1598 1599 pr_info("loaded\n"); 1600 return rc; 1601 } 1602 subsys_initcall_sync(vga_arb_device_init); 1603