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 unsigned int (*set_decode)(struct pci_dev *pdev, bool decode); 76 }; 77 78 static LIST_HEAD(vga_list); 79 static int vga_count, vga_decode_count; 80 static bool vga_arbiter_used; 81 static DEFINE_SPINLOCK(vga_lock); 82 static DECLARE_WAIT_QUEUE_HEAD(vga_wait_queue); 83 84 85 static const char *vga_iostate_to_str(unsigned int iostate) 86 { 87 /* Ignore VGA_RSRC_IO and VGA_RSRC_MEM */ 88 iostate &= VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; 89 switch (iostate) { 90 case VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM: 91 return "io+mem"; 92 case VGA_RSRC_LEGACY_IO: 93 return "io"; 94 case VGA_RSRC_LEGACY_MEM: 95 return "mem"; 96 } 97 return "none"; 98 } 99 100 static int vga_str_to_iostate(char *buf, int str_size, int *io_state) 101 { 102 /* we could in theory hand out locks on IO and mem 103 * separately to userspace but it can cause deadlocks */ 104 if (strncmp(buf, "none", 4) == 0) { 105 *io_state = VGA_RSRC_NONE; 106 return 1; 107 } 108 109 /* XXX We're not chekcing the str_size! */ 110 if (strncmp(buf, "io+mem", 6) == 0) 111 goto both; 112 else if (strncmp(buf, "io", 2) == 0) 113 goto both; 114 else if (strncmp(buf, "mem", 3) == 0) 115 goto both; 116 return 0; 117 both: 118 *io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; 119 return 1; 120 } 121 122 /* this is only used a cookie - it should not be dereferenced */ 123 static struct pci_dev *vga_default; 124 125 static void vga_arb_device_card_gone(struct pci_dev *pdev); 126 127 /* Find somebody in our list */ 128 static struct vga_device *vgadev_find(struct pci_dev *pdev) 129 { 130 struct vga_device *vgadev; 131 132 list_for_each_entry(vgadev, &vga_list, list) 133 if (pdev == vgadev->pdev) 134 return vgadev; 135 return NULL; 136 } 137 138 /** 139 * vga_default_device - return the default VGA device, for vgacon 140 * 141 * This can be defined by the platform. The default implementation 142 * is rather dumb and will probably only work properly on single 143 * vga card setups and/or x86 platforms. 144 * 145 * If your VGA default device is not PCI, you'll have to return 146 * NULL here. In this case, I assume it will not conflict with 147 * any PCI card. If this is not true, I'll have to define two archs 148 * hooks for enabling/disabling the VGA default device if that is 149 * possible. This may be a problem with real _ISA_ VGA cards, in 150 * addition to a PCI one. I don't know at this point how to deal 151 * with that card. Can theirs IOs be disabled at all ? If not, then 152 * I suppose it's a matter of having the proper arch hook telling 153 * us about it, so we basically never allow anybody to succeed a 154 * vga_get()... 155 */ 156 struct pci_dev *vga_default_device(void) 157 { 158 return vga_default; 159 } 160 EXPORT_SYMBOL_GPL(vga_default_device); 161 162 void vga_set_default_device(struct pci_dev *pdev) 163 { 164 if (vga_default == pdev) 165 return; 166 167 pci_dev_put(vga_default); 168 vga_default = pci_dev_get(pdev); 169 } 170 171 /** 172 * vga_remove_vgacon - deactivete vga console 173 * 174 * Unbind and unregister vgacon in case pdev is the default vga 175 * device. Can be called by gpu drivers on initialization to make 176 * sure vga register access done by vgacon will not disturb the 177 * device. 178 * 179 * @pdev: pci device. 180 */ 181 #if !defined(CONFIG_VGA_CONSOLE) 182 int vga_remove_vgacon(struct pci_dev *pdev) 183 { 184 return 0; 185 } 186 #elif !defined(CONFIG_DUMMY_CONSOLE) 187 int vga_remove_vgacon(struct pci_dev *pdev) 188 { 189 return -ENODEV; 190 } 191 #else 192 int vga_remove_vgacon(struct pci_dev *pdev) 193 { 194 int ret = 0; 195 196 if (pdev != vga_default) 197 return 0; 198 vgaarb_info(&pdev->dev, "deactivate vga console\n"); 199 200 console_lock(); 201 if (con_is_bound(&vga_con)) 202 ret = do_take_over_console(&dummy_con, 0, 203 MAX_NR_CONSOLES - 1, 1); 204 if (ret == 0) { 205 ret = do_unregister_con_driver(&vga_con); 206 207 /* Ignore "already unregistered". */ 208 if (ret == -ENODEV) 209 ret = 0; 210 } 211 console_unlock(); 212 213 return ret; 214 } 215 #endif 216 EXPORT_SYMBOL(vga_remove_vgacon); 217 218 /* If we don't ever use VGA arb we should avoid 219 turning off anything anywhere due to old X servers getting 220 confused about the boot device not being VGA */ 221 static void vga_check_first_use(void) 222 { 223 /* we should inform all GPUs in the system that 224 * VGA arb has occurred and to try and disable resources 225 * if they can */ 226 if (!vga_arbiter_used) { 227 vga_arbiter_used = true; 228 vga_arbiter_notify_clients(); 229 } 230 } 231 232 static struct vga_device *__vga_tryget(struct vga_device *vgadev, 233 unsigned int rsrc) 234 { 235 struct device *dev = &vgadev->pdev->dev; 236 unsigned int wants, legacy_wants, match; 237 struct vga_device *conflict; 238 unsigned int pci_bits; 239 u32 flags = 0; 240 241 /* Account for "normal" resources to lock. If we decode the legacy, 242 * counterpart, we need to request it as well 243 */ 244 if ((rsrc & VGA_RSRC_NORMAL_IO) && 245 (vgadev->decodes & VGA_RSRC_LEGACY_IO)) 246 rsrc |= VGA_RSRC_LEGACY_IO; 247 if ((rsrc & VGA_RSRC_NORMAL_MEM) && 248 (vgadev->decodes & VGA_RSRC_LEGACY_MEM)) 249 rsrc |= VGA_RSRC_LEGACY_MEM; 250 251 vgaarb_dbg(dev, "%s: %d\n", __func__, rsrc); 252 vgaarb_dbg(dev, "%s: owns: %d\n", __func__, vgadev->owns); 253 254 /* Check what resources we need to acquire */ 255 wants = rsrc & ~vgadev->owns; 256 257 /* We already own everything, just mark locked & bye bye */ 258 if (wants == 0) 259 goto lock_them; 260 261 /* We don't need to request a legacy resource, we just enable 262 * appropriate decoding and go 263 */ 264 legacy_wants = wants & VGA_RSRC_LEGACY_MASK; 265 if (legacy_wants == 0) 266 goto enable_them; 267 268 /* Ok, we don't, let's find out how we need to kick off */ 269 list_for_each_entry(conflict, &vga_list, list) { 270 unsigned int lwants = legacy_wants; 271 unsigned int change_bridge = 0; 272 273 /* Don't conflict with myself */ 274 if (vgadev == conflict) 275 continue; 276 277 /* We have a possible conflict. before we go further, we must 278 * check if we sit on the same bus as the conflicting device. 279 * if we don't, then we must tie both IO and MEM resources 280 * together since there is only a single bit controlling 281 * VGA forwarding on P2P bridges 282 */ 283 if (vgadev->pdev->bus != conflict->pdev->bus) { 284 change_bridge = 1; 285 lwants = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; 286 } 287 288 /* Check if the guy has a lock on the resource. If he does, 289 * return the conflicting entry 290 */ 291 if (conflict->locks & lwants) 292 return conflict; 293 294 /* Ok, now check if it owns the resource we want. We can 295 * lock resources that are not decoded, therefore a device 296 * can own resources it doesn't decode. 297 */ 298 match = lwants & conflict->owns; 299 if (!match) 300 continue; 301 302 /* looks like he doesn't have a lock, we can steal 303 * them from him 304 */ 305 306 flags = 0; 307 pci_bits = 0; 308 309 /* If we can't control legacy resources via the bridge, we 310 * also need to disable normal decoding. 311 */ 312 if (!conflict->bridge_has_one_vga) { 313 if ((match & conflict->decodes) & VGA_RSRC_LEGACY_MEM) 314 pci_bits |= PCI_COMMAND_MEMORY; 315 if ((match & conflict->decodes) & VGA_RSRC_LEGACY_IO) 316 pci_bits |= PCI_COMMAND_IO; 317 318 if (pci_bits) 319 flags |= PCI_VGA_STATE_CHANGE_DECODES; 320 } 321 322 if (change_bridge) 323 flags |= PCI_VGA_STATE_CHANGE_BRIDGE; 324 325 pci_set_vga_state(conflict->pdev, false, pci_bits, flags); 326 conflict->owns &= ~match; 327 328 /* If we disabled normal decoding, reflect it in owns */ 329 if (pci_bits & PCI_COMMAND_MEMORY) 330 conflict->owns &= ~VGA_RSRC_NORMAL_MEM; 331 if (pci_bits & PCI_COMMAND_IO) 332 conflict->owns &= ~VGA_RSRC_NORMAL_IO; 333 } 334 335 enable_them: 336 /* ok dude, we got it, everybody conflicting has been disabled, let's 337 * enable us. Mark any bits in "owns" regardless of whether we 338 * decoded them. We can lock resources we don't decode, therefore 339 * we must track them via "owns". 340 */ 341 flags = 0; 342 pci_bits = 0; 343 344 if (!vgadev->bridge_has_one_vga) { 345 flags |= PCI_VGA_STATE_CHANGE_DECODES; 346 if (wants & (VGA_RSRC_LEGACY_MEM|VGA_RSRC_NORMAL_MEM)) 347 pci_bits |= PCI_COMMAND_MEMORY; 348 if (wants & (VGA_RSRC_LEGACY_IO|VGA_RSRC_NORMAL_IO)) 349 pci_bits |= PCI_COMMAND_IO; 350 } 351 if (wants & VGA_RSRC_LEGACY_MASK) 352 flags |= PCI_VGA_STATE_CHANGE_BRIDGE; 353 354 pci_set_vga_state(vgadev->pdev, true, pci_bits, flags); 355 356 vgadev->owns |= wants; 357 lock_them: 358 vgadev->locks |= (rsrc & VGA_RSRC_LEGACY_MASK); 359 if (rsrc & VGA_RSRC_LEGACY_IO) 360 vgadev->io_lock_cnt++; 361 if (rsrc & VGA_RSRC_LEGACY_MEM) 362 vgadev->mem_lock_cnt++; 363 if (rsrc & VGA_RSRC_NORMAL_IO) 364 vgadev->io_norm_cnt++; 365 if (rsrc & VGA_RSRC_NORMAL_MEM) 366 vgadev->mem_norm_cnt++; 367 368 return NULL; 369 } 370 371 static void __vga_put(struct vga_device *vgadev, unsigned int rsrc) 372 { 373 struct device *dev = &vgadev->pdev->dev; 374 unsigned int old_locks = vgadev->locks; 375 376 vgaarb_dbg(dev, "%s\n", __func__); 377 378 /* Update our counters, and account for equivalent legacy resources 379 * if we decode them 380 */ 381 if ((rsrc & VGA_RSRC_NORMAL_IO) && vgadev->io_norm_cnt > 0) { 382 vgadev->io_norm_cnt--; 383 if (vgadev->decodes & VGA_RSRC_LEGACY_IO) 384 rsrc |= VGA_RSRC_LEGACY_IO; 385 } 386 if ((rsrc & VGA_RSRC_NORMAL_MEM) && vgadev->mem_norm_cnt > 0) { 387 vgadev->mem_norm_cnt--; 388 if (vgadev->decodes & VGA_RSRC_LEGACY_MEM) 389 rsrc |= VGA_RSRC_LEGACY_MEM; 390 } 391 if ((rsrc & VGA_RSRC_LEGACY_IO) && vgadev->io_lock_cnt > 0) 392 vgadev->io_lock_cnt--; 393 if ((rsrc & VGA_RSRC_LEGACY_MEM) && vgadev->mem_lock_cnt > 0) 394 vgadev->mem_lock_cnt--; 395 396 /* Just clear lock bits, we do lazy operations so we don't really 397 * have to bother about anything else at this point 398 */ 399 if (vgadev->io_lock_cnt == 0) 400 vgadev->locks &= ~VGA_RSRC_LEGACY_IO; 401 if (vgadev->mem_lock_cnt == 0) 402 vgadev->locks &= ~VGA_RSRC_LEGACY_MEM; 403 404 /* Kick the wait queue in case somebody was waiting if we actually 405 * released something 406 */ 407 if (old_locks != vgadev->locks) 408 wake_up_all(&vga_wait_queue); 409 } 410 411 /** 412 * vga_get - acquire & locks VGA resources 413 * @pdev: pci device of the VGA card or NULL for the system default 414 * @rsrc: bit mask of resources to acquire and lock 415 * @interruptible: blocking should be interruptible by signals ? 416 * 417 * This function acquires VGA resources for the given card and mark those 418 * resources locked. If the resource requested are "normal" (and not legacy) 419 * resources, the arbiter will first check whether the card is doing legacy 420 * decoding for that type of resource. If yes, the lock is "converted" into a 421 * legacy resource lock. 422 * 423 * The arbiter will first look for all VGA cards that might conflict and disable 424 * their IOs and/or Memory access, including VGA forwarding on P2P bridges if 425 * necessary, so that the requested resources can be used. Then, the card is 426 * marked as locking these resources and the IO and/or Memory accesses are 427 * enabled on the card (including VGA forwarding on parent P2P bridges if any). 428 * 429 * This function will block if some conflicting card is already locking one of 430 * the required resources (or any resource on a different bus segment, since P2P 431 * bridges don't differentiate VGA memory and IO afaik). You can indicate 432 * whether this blocking should be interruptible by a signal (for userland 433 * interface) or not. 434 * 435 * Must not be called at interrupt time or in atomic context. If the card 436 * already owns the resources, the function succeeds. Nested calls are 437 * supported (a per-resource counter is maintained) 438 * 439 * On success, release the VGA resource again with vga_put(). 440 * 441 * Returns: 442 * 443 * 0 on success, negative error code on failure. 444 */ 445 int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible) 446 { 447 struct vga_device *vgadev, *conflict; 448 unsigned long flags; 449 wait_queue_entry_t wait; 450 int rc = 0; 451 452 vga_check_first_use(); 453 /* The one who calls us should check for this, but lets be sure... */ 454 if (pdev == NULL) 455 pdev = vga_default_device(); 456 if (pdev == NULL) 457 return 0; 458 459 for (;;) { 460 spin_lock_irqsave(&vga_lock, flags); 461 vgadev = vgadev_find(pdev); 462 if (vgadev == NULL) { 463 spin_unlock_irqrestore(&vga_lock, flags); 464 rc = -ENODEV; 465 break; 466 } 467 conflict = __vga_tryget(vgadev, rsrc); 468 spin_unlock_irqrestore(&vga_lock, flags); 469 if (conflict == NULL) 470 break; 471 472 473 /* We have a conflict, we wait until somebody kicks the 474 * work queue. Currently we have one work queue that we 475 * kick each time some resources are released, but it would 476 * be fairly easy to have a per device one so that we only 477 * need to attach to the conflicting device 478 */ 479 init_waitqueue_entry(&wait, current); 480 add_wait_queue(&vga_wait_queue, &wait); 481 set_current_state(interruptible ? 482 TASK_INTERRUPTIBLE : 483 TASK_UNINTERRUPTIBLE); 484 if (interruptible && signal_pending(current)) { 485 __set_current_state(TASK_RUNNING); 486 remove_wait_queue(&vga_wait_queue, &wait); 487 rc = -ERESTARTSYS; 488 break; 489 } 490 schedule(); 491 remove_wait_queue(&vga_wait_queue, &wait); 492 } 493 return rc; 494 } 495 EXPORT_SYMBOL(vga_get); 496 497 /** 498 * vga_tryget - try to acquire & lock legacy VGA resources 499 * @pdev: pci devivce of VGA card or NULL for system default 500 * @rsrc: bit mask of resources to acquire and lock 501 * 502 * This function performs the same operation as vga_get(), but will return an 503 * error (-EBUSY) instead of blocking if the resources are already locked by 504 * another card. It can be called in any context 505 * 506 * On success, release the VGA resource again with vga_put(). 507 * 508 * Returns: 509 * 510 * 0 on success, negative error code on failure. 511 */ 512 static int vga_tryget(struct pci_dev *pdev, unsigned int rsrc) 513 { 514 struct vga_device *vgadev; 515 unsigned long flags; 516 int rc = 0; 517 518 vga_check_first_use(); 519 520 /* The one who calls us should check for this, but lets be sure... */ 521 if (pdev == NULL) 522 pdev = vga_default_device(); 523 if (pdev == NULL) 524 return 0; 525 spin_lock_irqsave(&vga_lock, flags); 526 vgadev = vgadev_find(pdev); 527 if (vgadev == NULL) { 528 rc = -ENODEV; 529 goto bail; 530 } 531 if (__vga_tryget(vgadev, rsrc)) 532 rc = -EBUSY; 533 bail: 534 spin_unlock_irqrestore(&vga_lock, flags); 535 return rc; 536 } 537 538 /** 539 * vga_put - release lock on legacy VGA resources 540 * @pdev: pci device of VGA card or NULL for system default 541 * @rsrc: but mask of resource to release 542 * 543 * This fuction releases resources previously locked by vga_get() or 544 * vga_tryget(). The resources aren't disabled right away, so that a subsequence 545 * vga_get() on the same card will succeed immediately. Resources have a 546 * counter, so locks are only released if the counter reaches 0. 547 */ 548 void vga_put(struct pci_dev *pdev, unsigned int rsrc) 549 { 550 struct vga_device *vgadev; 551 unsigned long flags; 552 553 /* The one who calls us should check for this, but lets be sure... */ 554 if (pdev == NULL) 555 pdev = vga_default_device(); 556 if (pdev == NULL) 557 return; 558 spin_lock_irqsave(&vga_lock, flags); 559 vgadev = vgadev_find(pdev); 560 if (vgadev == NULL) 561 goto bail; 562 __vga_put(vgadev, rsrc); 563 bail: 564 spin_unlock_irqrestore(&vga_lock, flags); 565 } 566 EXPORT_SYMBOL(vga_put); 567 568 static void __init vga_select_framebuffer_device(struct pci_dev *pdev) 569 { 570 #if defined(CONFIG_X86) || defined(CONFIG_IA64) 571 struct device *dev = &pdev->dev; 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 /* 587 * Override vga_arbiter_add_pci_device()'s I/O based detection 588 * as it may take the wrong device (e.g. on Apple system under 589 * EFI). 590 * 591 * Select the device owning the boot framebuffer if there is 592 * one. 593 */ 594 595 /* Does firmware framebuffer belong to us? */ 596 for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) { 597 flags = pci_resource_flags(pdev, i); 598 599 if ((flags & IORESOURCE_MEM) == 0) 600 continue; 601 602 start = pci_resource_start(pdev, i); 603 end = pci_resource_end(pdev, i); 604 605 if (!start || !end) 606 continue; 607 608 if (base < start || limit >= end) 609 continue; 610 611 if (!vga_default_device()) 612 vgaarb_info(dev, "setting as boot device\n"); 613 else if (pdev != vga_default_device()) 614 vgaarb_info(dev, "overriding boot device\n"); 615 vga_set_default_device(pdev); 616 } 617 #endif 618 } 619 620 static bool vga_arb_integrated_gpu(struct device *dev) 621 { 622 #if defined(CONFIG_ACPI) 623 struct acpi_device *adev = ACPI_COMPANION(dev); 624 625 return adev && !strcmp(acpi_device_hid(adev), ACPI_VIDEO_HID); 626 #else 627 return false; 628 #endif 629 } 630 631 /* 632 * Return true if vgadev is a better default VGA device than the best one 633 * we've seen so far. 634 */ 635 static bool vga_is_boot_device(struct vga_device *vgadev) 636 { 637 struct vga_device *boot_vga = vgadev_find(vga_default_device()); 638 639 /* 640 * We select the default VGA device in this order: 641 * Firmware framebuffer (see vga_arb_select_default_device()) 642 * Legacy VGA device (owns VGA_RSRC_LEGACY_MASK) 643 * Non-legacy integrated device (see vga_arb_select_default_device()) 644 * Non-legacy discrete device (see vga_arb_select_default_device()) 645 * Other device (see vga_arb_select_default_device()) 646 */ 647 648 /* 649 * A legacy VGA device has MEM and IO enabled and any bridges 650 * leading to it have PCI_BRIDGE_CTL_VGA enabled so the legacy 651 * resources ([mem 0xa0000-0xbffff], [io 0x3b0-0x3bb], etc) are 652 * routed to it. 653 * 654 * We use the first one we find, so if we've already found one, 655 * vgadev is no better. 656 */ 657 if (boot_vga) 658 return false; 659 660 if ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK) 661 return true; 662 663 return false; 664 } 665 666 /* 667 * Rules for using a bridge to control a VGA descendant decoding: if a bridge 668 * has only one VGA descendant then it can be used to control the VGA routing 669 * for that device. It should always use the bridge closest to the device to 670 * control it. If a bridge has a direct VGA descendant, but also have a sub- 671 * bridge VGA descendant then we cannot use that bridge to control the direct 672 * VGA descendant. So for every device we register, we need to iterate all 673 * its parent bridges so we can invalidate any devices using them properly. 674 */ 675 static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev) 676 { 677 struct vga_device *same_bridge_vgadev; 678 struct pci_bus *new_bus, *bus; 679 struct pci_dev *new_bridge, *bridge; 680 681 vgadev->bridge_has_one_vga = true; 682 683 if (list_empty(&vga_list)) 684 return; 685 686 /* okay iterate the new devices bridge hierarachy */ 687 new_bus = vgadev->pdev->bus; 688 while (new_bus) { 689 new_bridge = new_bus->self; 690 691 /* go through list of devices already registered */ 692 list_for_each_entry(same_bridge_vgadev, &vga_list, list) { 693 bus = same_bridge_vgadev->pdev->bus; 694 bridge = bus->self; 695 696 /* see if the share a bridge with this device */ 697 if (new_bridge == bridge) { 698 /* 699 * If their direct parent bridge is the same 700 * as any bridge of this device then it can't 701 * be used for that device. 702 */ 703 same_bridge_vgadev->bridge_has_one_vga = false; 704 } 705 706 /* 707 * Now iterate the previous devices bridge hierarchy. 708 * If the new devices parent bridge is in the other 709 * devices hierarchy then we can't use it to control 710 * this device 711 */ 712 while (bus) { 713 bridge = bus->self; 714 715 if (bridge && bridge == vgadev->pdev->bus->self) 716 vgadev->bridge_has_one_vga = false; 717 718 bus = bus->parent; 719 } 720 } 721 new_bus = new_bus->parent; 722 } 723 } 724 725 /* 726 * Currently, we assume that the "initial" setup of the system is 727 * not sane, that is we come up with conflicting devices and let 728 * the arbiter's client decides if devices decodes or not legacy 729 * things. 730 */ 731 static bool vga_arbiter_add_pci_device(struct pci_dev *pdev) 732 { 733 struct vga_device *vgadev; 734 unsigned long flags; 735 struct pci_bus *bus; 736 struct pci_dev *bridge; 737 u16 cmd; 738 739 /* Only deal with VGA class devices */ 740 if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA) 741 return false; 742 743 /* Allocate structure */ 744 vgadev = kzalloc(sizeof(struct vga_device), GFP_KERNEL); 745 if (vgadev == NULL) { 746 vgaarb_err(&pdev->dev, "failed to allocate VGA arbiter data\n"); 747 /* 748 * What to do on allocation failure ? For now, let's just do 749 * nothing, I'm not sure there is anything saner to be done. 750 */ 751 return false; 752 } 753 754 /* Take lock & check for duplicates */ 755 spin_lock_irqsave(&vga_lock, flags); 756 if (vgadev_find(pdev) != NULL) { 757 BUG_ON(1); 758 goto fail; 759 } 760 vgadev->pdev = pdev; 761 762 /* By default, assume we decode everything */ 763 vgadev->decodes = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM | 764 VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM; 765 766 /* by default mark it as decoding */ 767 vga_decode_count++; 768 /* Mark that we "own" resources based on our enables, we will 769 * clear that below if the bridge isn't forwarding 770 */ 771 pci_read_config_word(pdev, PCI_COMMAND, &cmd); 772 if (cmd & PCI_COMMAND_IO) 773 vgadev->owns |= VGA_RSRC_LEGACY_IO; 774 if (cmd & PCI_COMMAND_MEMORY) 775 vgadev->owns |= VGA_RSRC_LEGACY_MEM; 776 777 /* Check if VGA cycles can get down to us */ 778 bus = pdev->bus; 779 while (bus) { 780 bridge = bus->self; 781 if (bridge) { 782 u16 l; 783 784 pci_read_config_word(bridge, PCI_BRIDGE_CONTROL, &l); 785 if (!(l & PCI_BRIDGE_CTL_VGA)) { 786 vgadev->owns = 0; 787 break; 788 } 789 } 790 bus = bus->parent; 791 } 792 793 if (vga_is_boot_device(vgadev)) { 794 vgaarb_info(&pdev->dev, "setting as boot VGA device%s\n", 795 vga_default_device() ? 796 " (overriding previous)" : ""); 797 vga_set_default_device(pdev); 798 } 799 800 vga_arbiter_check_bridge_sharing(vgadev); 801 802 /* Add to the list */ 803 list_add_tail(&vgadev->list, &vga_list); 804 vga_count++; 805 vgaarb_info(&pdev->dev, "VGA device added: decodes=%s,owns=%s,locks=%s\n", 806 vga_iostate_to_str(vgadev->decodes), 807 vga_iostate_to_str(vgadev->owns), 808 vga_iostate_to_str(vgadev->locks)); 809 810 spin_unlock_irqrestore(&vga_lock, flags); 811 return true; 812 fail: 813 spin_unlock_irqrestore(&vga_lock, flags); 814 kfree(vgadev); 815 return false; 816 } 817 818 static bool vga_arbiter_del_pci_device(struct pci_dev *pdev) 819 { 820 struct vga_device *vgadev; 821 unsigned long flags; 822 bool ret = true; 823 824 spin_lock_irqsave(&vga_lock, flags); 825 vgadev = vgadev_find(pdev); 826 if (vgadev == NULL) { 827 ret = false; 828 goto bail; 829 } 830 831 if (vga_default == pdev) 832 vga_set_default_device(NULL); 833 834 if (vgadev->decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM)) 835 vga_decode_count--; 836 837 /* Remove entry from list */ 838 list_del(&vgadev->list); 839 vga_count--; 840 /* Notify userland driver that the device is gone so it discards 841 * it's copies of the pci_dev pointer 842 */ 843 vga_arb_device_card_gone(pdev); 844 845 /* Wake up all possible waiters */ 846 wake_up_all(&vga_wait_queue); 847 bail: 848 spin_unlock_irqrestore(&vga_lock, flags); 849 kfree(vgadev); 850 return ret; 851 } 852 853 /* this is called with the lock */ 854 static inline void vga_update_device_decodes(struct vga_device *vgadev, 855 int new_decodes) 856 { 857 struct device *dev = &vgadev->pdev->dev; 858 int old_decodes, decodes_removed, decodes_unlocked; 859 860 old_decodes = vgadev->decodes; 861 decodes_removed = ~new_decodes & old_decodes; 862 decodes_unlocked = vgadev->locks & decodes_removed; 863 vgadev->decodes = new_decodes; 864 865 vgaarb_info(dev, "changed VGA decodes: olddecodes=%s,decodes=%s:owns=%s\n", 866 vga_iostate_to_str(old_decodes), 867 vga_iostate_to_str(vgadev->decodes), 868 vga_iostate_to_str(vgadev->owns)); 869 870 /* if we removed locked decodes, lock count goes to zero, and release */ 871 if (decodes_unlocked) { 872 if (decodes_unlocked & VGA_RSRC_LEGACY_IO) 873 vgadev->io_lock_cnt = 0; 874 if (decodes_unlocked & VGA_RSRC_LEGACY_MEM) 875 vgadev->mem_lock_cnt = 0; 876 __vga_put(vgadev, decodes_unlocked); 877 } 878 879 /* change decodes counter */ 880 if (old_decodes & VGA_RSRC_LEGACY_MASK && 881 !(new_decodes & VGA_RSRC_LEGACY_MASK)) 882 vga_decode_count--; 883 if (!(old_decodes & VGA_RSRC_LEGACY_MASK) && 884 new_decodes & VGA_RSRC_LEGACY_MASK) 885 vga_decode_count++; 886 vgaarb_dbg(dev, "decoding count now is: %d\n", vga_decode_count); 887 } 888 889 static void __vga_set_legacy_decoding(struct pci_dev *pdev, 890 unsigned int decodes, 891 bool userspace) 892 { 893 struct vga_device *vgadev; 894 unsigned long flags; 895 896 decodes &= VGA_RSRC_LEGACY_MASK; 897 898 spin_lock_irqsave(&vga_lock, flags); 899 vgadev = vgadev_find(pdev); 900 if (vgadev == NULL) 901 goto bail; 902 903 /* don't let userspace futz with kernel driver decodes */ 904 if (userspace && vgadev->set_decode) 905 goto bail; 906 907 /* update the device decodes + counter */ 908 vga_update_device_decodes(vgadev, decodes); 909 910 /* XXX if somebody is going from "doesn't decode" to "decodes" state 911 * here, additional care must be taken as we may have pending owner 912 * ship of non-legacy region ... 913 */ 914 bail: 915 spin_unlock_irqrestore(&vga_lock, flags); 916 } 917 918 /** 919 * vga_set_legacy_decoding 920 * @pdev: pci device of the VGA card 921 * @decodes: bit mask of what legacy regions the card decodes 922 * 923 * Indicates to the arbiter if the card decodes legacy VGA IOs, legacy VGA 924 * Memory, both, or none. All cards default to both, the card driver (fbdev for 925 * example) should tell the arbiter if it has disabled legacy decoding, so the 926 * card can be left out of the arbitration process (and can be safe to take 927 * interrupts at any time. 928 */ 929 void vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes) 930 { 931 __vga_set_legacy_decoding(pdev, decodes, false); 932 } 933 EXPORT_SYMBOL(vga_set_legacy_decoding); 934 935 /** 936 * vga_client_register - register or unregister a VGA arbitration client 937 * @pdev: pci device of the VGA client 938 * @set_decode: vga decode change callback 939 * 940 * Clients have two callback mechanisms they can use. 941 * 942 * @set_decode callback: If a client can disable its GPU VGA resource, it 943 * will get a callback from this to set the encode/decode state. 944 * 945 * Rationale: we cannot disable VGA decode resources unconditionally some single 946 * GPU laptops seem to require ACPI or BIOS access to the VGA registers to 947 * control things like backlights etc. Hopefully newer multi-GPU laptops do 948 * something saner, and desktops won't have any special ACPI for this. The 949 * driver will get a callback when VGA arbitration is first used by userspace 950 * since some older X servers have issues. 951 * 952 * This function does not check whether a client for @pdev has been registered 953 * already. 954 * 955 * To unregister just call vga_client_unregister(). 956 * 957 * Returns: 0 on success, -1 on failure 958 */ 959 int vga_client_register(struct pci_dev *pdev, 960 unsigned int (*set_decode)(struct pci_dev *pdev, bool decode)) 961 { 962 int ret = -ENODEV; 963 struct vga_device *vgadev; 964 unsigned long flags; 965 966 spin_lock_irqsave(&vga_lock, flags); 967 vgadev = vgadev_find(pdev); 968 if (!vgadev) 969 goto bail; 970 971 vgadev->set_decode = set_decode; 972 ret = 0; 973 974 bail: 975 spin_unlock_irqrestore(&vga_lock, flags); 976 return ret; 977 978 } 979 EXPORT_SYMBOL(vga_client_register); 980 981 /* 982 * Char driver implementation 983 * 984 * Semantics is: 985 * 986 * open : open user instance of the arbitrer. by default, it's 987 * attached to the default VGA device of the system. 988 * 989 * close : close user instance, release locks 990 * 991 * read : return a string indicating the status of the target. 992 * an IO state string is of the form {io,mem,io+mem,none}, 993 * mc and ic are respectively mem and io lock counts (for 994 * debugging/diagnostic only). "decodes" indicate what the 995 * card currently decodes, "owns" indicates what is currently 996 * enabled on it, and "locks" indicates what is locked by this 997 * card. If the card is unplugged, we get "invalid" then for 998 * card_ID and an -ENODEV error is returned for any command 999 * until a new card is targeted 1000 * 1001 * "<card_ID>,decodes=<io_state>,owns=<io_state>,locks=<io_state> (ic,mc)" 1002 * 1003 * write : write a command to the arbiter. List of commands is: 1004 * 1005 * target <card_ID> : switch target to card <card_ID> (see below) 1006 * lock <io_state> : acquires locks on target ("none" is invalid io_state) 1007 * trylock <io_state> : non-blocking acquire locks on target 1008 * unlock <io_state> : release locks on target 1009 * unlock all : release all locks on target held by this user 1010 * decodes <io_state> : set the legacy decoding attributes for the card 1011 * 1012 * poll : event if something change on any card (not just the target) 1013 * 1014 * card_ID is of the form "PCI:domain:bus:dev.fn". It can be set to "default" 1015 * to go back to the system default card (TODO: not implemented yet). 1016 * Currently, only PCI is supported as a prefix, but the userland API may 1017 * support other bus types in the future, even if the current kernel 1018 * implementation doesn't. 1019 * 1020 * Note about locks: 1021 * 1022 * The driver keeps track of which user has what locks on which card. It 1023 * supports stacking, like the kernel one. This complexifies the implementation 1024 * a bit, but makes the arbiter more tolerant to userspace problems and able 1025 * to properly cleanup in all cases when a process dies. 1026 * Currently, a max of 16 cards simultaneously can have locks issued from 1027 * userspace for a given user (file descriptor instance) of the arbiter. 1028 * 1029 * If the device is hot-unplugged, there is a hook inside the module to notify 1030 * they being added/removed in the system and automatically added/removed in 1031 * the arbiter. 1032 */ 1033 1034 #define MAX_USER_CARDS CONFIG_VGA_ARB_MAX_GPUS 1035 #define PCI_INVALID_CARD ((struct pci_dev *)-1UL) 1036 1037 /* 1038 * Each user has an array of these, tracking which cards have locks 1039 */ 1040 struct vga_arb_user_card { 1041 struct pci_dev *pdev; 1042 unsigned int mem_cnt; 1043 unsigned int io_cnt; 1044 }; 1045 1046 struct vga_arb_private { 1047 struct list_head list; 1048 struct pci_dev *target; 1049 struct vga_arb_user_card cards[MAX_USER_CARDS]; 1050 spinlock_t lock; 1051 }; 1052 1053 static LIST_HEAD(vga_user_list); 1054 static DEFINE_SPINLOCK(vga_user_lock); 1055 1056 1057 /* 1058 * This function gets a string in the format: "PCI:domain:bus:dev.fn" and 1059 * returns the respective values. If the string is not in this format, 1060 * it returns 0. 1061 */ 1062 static int vga_pci_str_to_vars(char *buf, int count, unsigned int *domain, 1063 unsigned int *bus, unsigned int *devfn) 1064 { 1065 int n; 1066 unsigned int slot, func; 1067 1068 1069 n = sscanf(buf, "PCI:%x:%x:%x.%x", domain, bus, &slot, &func); 1070 if (n != 4) 1071 return 0; 1072 1073 *devfn = PCI_DEVFN(slot, func); 1074 1075 return 1; 1076 } 1077 1078 static ssize_t vga_arb_read(struct file *file, char __user *buf, 1079 size_t count, loff_t *ppos) 1080 { 1081 struct vga_arb_private *priv = file->private_data; 1082 struct vga_device *vgadev; 1083 struct pci_dev *pdev; 1084 unsigned long flags; 1085 size_t len; 1086 int rc; 1087 char *lbuf; 1088 1089 lbuf = kmalloc(1024, GFP_KERNEL); 1090 if (lbuf == NULL) 1091 return -ENOMEM; 1092 1093 /* Shields against vga_arb_device_card_gone (pci_dev going 1094 * away), and allows access to vga list 1095 */ 1096 spin_lock_irqsave(&vga_lock, flags); 1097 1098 /* If we are targeting the default, use it */ 1099 pdev = priv->target; 1100 if (pdev == NULL || pdev == PCI_INVALID_CARD) { 1101 spin_unlock_irqrestore(&vga_lock, flags); 1102 len = sprintf(lbuf, "invalid"); 1103 goto done; 1104 } 1105 1106 /* Find card vgadev structure */ 1107 vgadev = vgadev_find(pdev); 1108 if (vgadev == NULL) { 1109 /* Wow, it's not in the list, that shouldn't happen, 1110 * let's fix us up and return invalid card 1111 */ 1112 if (pdev == priv->target) 1113 vga_arb_device_card_gone(pdev); 1114 spin_unlock_irqrestore(&vga_lock, flags); 1115 len = sprintf(lbuf, "invalid"); 1116 goto done; 1117 } 1118 1119 /* Fill the buffer with infos */ 1120 len = snprintf(lbuf, 1024, 1121 "count:%d,PCI:%s,decodes=%s,owns=%s,locks=%s(%d:%d)\n", 1122 vga_decode_count, pci_name(pdev), 1123 vga_iostate_to_str(vgadev->decodes), 1124 vga_iostate_to_str(vgadev->owns), 1125 vga_iostate_to_str(vgadev->locks), 1126 vgadev->io_lock_cnt, vgadev->mem_lock_cnt); 1127 1128 spin_unlock_irqrestore(&vga_lock, flags); 1129 done: 1130 1131 /* Copy that to user */ 1132 if (len > count) 1133 len = count; 1134 rc = copy_to_user(buf, lbuf, len); 1135 kfree(lbuf); 1136 if (rc) 1137 return -EFAULT; 1138 return len; 1139 } 1140 1141 /* 1142 * TODO: To avoid parsing inside kernel and to improve the speed we may 1143 * consider use ioctl here 1144 */ 1145 static ssize_t vga_arb_write(struct file *file, const char __user *buf, 1146 size_t count, loff_t *ppos) 1147 { 1148 struct vga_arb_private *priv = file->private_data; 1149 struct vga_arb_user_card *uc = NULL; 1150 struct pci_dev *pdev; 1151 1152 unsigned int io_state; 1153 1154 char kbuf[64], *curr_pos; 1155 size_t remaining = count; 1156 1157 int ret_val; 1158 int i; 1159 1160 if (count >= sizeof(kbuf)) 1161 return -EINVAL; 1162 if (copy_from_user(kbuf, buf, count)) 1163 return -EFAULT; 1164 curr_pos = kbuf; 1165 kbuf[count] = '\0'; /* Just to make sure... */ 1166 1167 if (strncmp(curr_pos, "lock ", 5) == 0) { 1168 curr_pos += 5; 1169 remaining -= 5; 1170 1171 pr_debug("client 0x%p called 'lock'\n", priv); 1172 1173 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { 1174 ret_val = -EPROTO; 1175 goto done; 1176 } 1177 if (io_state == VGA_RSRC_NONE) { 1178 ret_val = -EPROTO; 1179 goto done; 1180 } 1181 1182 pdev = priv->target; 1183 if (priv->target == NULL) { 1184 ret_val = -ENODEV; 1185 goto done; 1186 } 1187 1188 vga_get_uninterruptible(pdev, io_state); 1189 1190 /* Update the client's locks lists... */ 1191 for (i = 0; i < MAX_USER_CARDS; i++) { 1192 if (priv->cards[i].pdev == pdev) { 1193 if (io_state & VGA_RSRC_LEGACY_IO) 1194 priv->cards[i].io_cnt++; 1195 if (io_state & VGA_RSRC_LEGACY_MEM) 1196 priv->cards[i].mem_cnt++; 1197 break; 1198 } 1199 } 1200 1201 ret_val = count; 1202 goto done; 1203 } else if (strncmp(curr_pos, "unlock ", 7) == 0) { 1204 curr_pos += 7; 1205 remaining -= 7; 1206 1207 pr_debug("client 0x%p called 'unlock'\n", priv); 1208 1209 if (strncmp(curr_pos, "all", 3) == 0) 1210 io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; 1211 else { 1212 if (!vga_str_to_iostate 1213 (curr_pos, remaining, &io_state)) { 1214 ret_val = -EPROTO; 1215 goto done; 1216 } 1217 /* TODO: Add this? 1218 if (io_state == VGA_RSRC_NONE) { 1219 ret_val = -EPROTO; 1220 goto done; 1221 } 1222 */ 1223 } 1224 1225 pdev = priv->target; 1226 if (priv->target == NULL) { 1227 ret_val = -ENODEV; 1228 goto done; 1229 } 1230 for (i = 0; i < MAX_USER_CARDS; i++) { 1231 if (priv->cards[i].pdev == pdev) 1232 uc = &priv->cards[i]; 1233 } 1234 1235 if (!uc) { 1236 ret_val = -EINVAL; 1237 goto done; 1238 } 1239 1240 if (io_state & VGA_RSRC_LEGACY_IO && uc->io_cnt == 0) { 1241 ret_val = -EINVAL; 1242 goto done; 1243 } 1244 1245 if (io_state & VGA_RSRC_LEGACY_MEM && uc->mem_cnt == 0) { 1246 ret_val = -EINVAL; 1247 goto done; 1248 } 1249 1250 vga_put(pdev, io_state); 1251 1252 if (io_state & VGA_RSRC_LEGACY_IO) 1253 uc->io_cnt--; 1254 if (io_state & VGA_RSRC_LEGACY_MEM) 1255 uc->mem_cnt--; 1256 1257 ret_val = count; 1258 goto done; 1259 } else if (strncmp(curr_pos, "trylock ", 8) == 0) { 1260 curr_pos += 8; 1261 remaining -= 8; 1262 1263 pr_debug("client 0x%p called 'trylock'\n", priv); 1264 1265 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { 1266 ret_val = -EPROTO; 1267 goto done; 1268 } 1269 /* TODO: Add this? 1270 if (io_state == VGA_RSRC_NONE) { 1271 ret_val = -EPROTO; 1272 goto done; 1273 } 1274 */ 1275 1276 pdev = priv->target; 1277 if (priv->target == NULL) { 1278 ret_val = -ENODEV; 1279 goto done; 1280 } 1281 1282 if (vga_tryget(pdev, io_state)) { 1283 /* Update the client's locks lists... */ 1284 for (i = 0; i < MAX_USER_CARDS; i++) { 1285 if (priv->cards[i].pdev == pdev) { 1286 if (io_state & VGA_RSRC_LEGACY_IO) 1287 priv->cards[i].io_cnt++; 1288 if (io_state & VGA_RSRC_LEGACY_MEM) 1289 priv->cards[i].mem_cnt++; 1290 break; 1291 } 1292 } 1293 ret_val = count; 1294 goto done; 1295 } else { 1296 ret_val = -EBUSY; 1297 goto done; 1298 } 1299 1300 } else if (strncmp(curr_pos, "target ", 7) == 0) { 1301 unsigned int domain, bus, devfn; 1302 struct vga_device *vgadev; 1303 1304 curr_pos += 7; 1305 remaining -= 7; 1306 pr_debug("client 0x%p called 'target'\n", priv); 1307 /* if target is default */ 1308 if (!strncmp(curr_pos, "default", 7)) 1309 pdev = pci_dev_get(vga_default_device()); 1310 else { 1311 if (!vga_pci_str_to_vars(curr_pos, remaining, 1312 &domain, &bus, &devfn)) { 1313 ret_val = -EPROTO; 1314 goto done; 1315 } 1316 pdev = pci_get_domain_bus_and_slot(domain, bus, devfn); 1317 if (!pdev) { 1318 pr_debug("invalid PCI address %04x:%02x:%02x.%x\n", 1319 domain, bus, PCI_SLOT(devfn), 1320 PCI_FUNC(devfn)); 1321 ret_val = -ENODEV; 1322 goto done; 1323 } 1324 1325 pr_debug("%s ==> %04x:%02x:%02x.%x pdev %p\n", curr_pos, 1326 domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn), 1327 pdev); 1328 } 1329 1330 vgadev = vgadev_find(pdev); 1331 pr_debug("vgadev %p\n", vgadev); 1332 if (vgadev == NULL) { 1333 if (pdev) { 1334 vgaarb_dbg(&pdev->dev, "not a VGA device\n"); 1335 pci_dev_put(pdev); 1336 } 1337 1338 ret_val = -ENODEV; 1339 goto done; 1340 } 1341 1342 priv->target = pdev; 1343 for (i = 0; i < MAX_USER_CARDS; i++) { 1344 if (priv->cards[i].pdev == pdev) 1345 break; 1346 if (priv->cards[i].pdev == NULL) { 1347 priv->cards[i].pdev = pdev; 1348 priv->cards[i].io_cnt = 0; 1349 priv->cards[i].mem_cnt = 0; 1350 break; 1351 } 1352 } 1353 if (i == MAX_USER_CARDS) { 1354 vgaarb_dbg(&pdev->dev, "maximum user cards (%d) number reached, ignoring this one!\n", 1355 MAX_USER_CARDS); 1356 pci_dev_put(pdev); 1357 /* XXX: which value to return? */ 1358 ret_val = -ENOMEM; 1359 goto done; 1360 } 1361 1362 ret_val = count; 1363 pci_dev_put(pdev); 1364 goto done; 1365 1366 1367 } else if (strncmp(curr_pos, "decodes ", 8) == 0) { 1368 curr_pos += 8; 1369 remaining -= 8; 1370 pr_debug("client 0x%p called 'decodes'\n", priv); 1371 1372 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { 1373 ret_val = -EPROTO; 1374 goto done; 1375 } 1376 pdev = priv->target; 1377 if (priv->target == NULL) { 1378 ret_val = -ENODEV; 1379 goto done; 1380 } 1381 1382 __vga_set_legacy_decoding(pdev, io_state, true); 1383 ret_val = count; 1384 goto done; 1385 } 1386 /* If we got here, the message written is not part of the protocol! */ 1387 return -EPROTO; 1388 1389 done: 1390 return ret_val; 1391 } 1392 1393 static __poll_t vga_arb_fpoll(struct file *file, poll_table *wait) 1394 { 1395 pr_debug("%s\n", __func__); 1396 1397 poll_wait(file, &vga_wait_queue, wait); 1398 return EPOLLIN; 1399 } 1400 1401 static int vga_arb_open(struct inode *inode, struct file *file) 1402 { 1403 struct vga_arb_private *priv; 1404 unsigned long flags; 1405 1406 pr_debug("%s\n", __func__); 1407 1408 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 1409 if (priv == NULL) 1410 return -ENOMEM; 1411 spin_lock_init(&priv->lock); 1412 file->private_data = priv; 1413 1414 spin_lock_irqsave(&vga_user_lock, flags); 1415 list_add(&priv->list, &vga_user_list); 1416 spin_unlock_irqrestore(&vga_user_lock, flags); 1417 1418 /* Set the client' lists of locks */ 1419 priv->target = vga_default_device(); /* Maybe this is still null! */ 1420 priv->cards[0].pdev = priv->target; 1421 priv->cards[0].io_cnt = 0; 1422 priv->cards[0].mem_cnt = 0; 1423 1424 1425 return 0; 1426 } 1427 1428 static int vga_arb_release(struct inode *inode, struct file *file) 1429 { 1430 struct vga_arb_private *priv = file->private_data; 1431 struct vga_arb_user_card *uc; 1432 unsigned long flags; 1433 int i; 1434 1435 pr_debug("%s\n", __func__); 1436 1437 spin_lock_irqsave(&vga_user_lock, flags); 1438 list_del(&priv->list); 1439 for (i = 0; i < MAX_USER_CARDS; i++) { 1440 uc = &priv->cards[i]; 1441 if (uc->pdev == NULL) 1442 continue; 1443 vgaarb_dbg(&uc->pdev->dev, "uc->io_cnt == %d, uc->mem_cnt == %d\n", 1444 uc->io_cnt, uc->mem_cnt); 1445 while (uc->io_cnt--) 1446 vga_put(uc->pdev, VGA_RSRC_LEGACY_IO); 1447 while (uc->mem_cnt--) 1448 vga_put(uc->pdev, VGA_RSRC_LEGACY_MEM); 1449 } 1450 spin_unlock_irqrestore(&vga_user_lock, flags); 1451 1452 kfree(priv); 1453 1454 return 0; 1455 } 1456 1457 static void vga_arb_device_card_gone(struct pci_dev *pdev) 1458 { 1459 } 1460 1461 /* 1462 * callback any registered clients to let them know we have a 1463 * change in VGA cards 1464 */ 1465 static void vga_arbiter_notify_clients(void) 1466 { 1467 struct vga_device *vgadev; 1468 unsigned long flags; 1469 uint32_t new_decodes; 1470 bool new_state; 1471 1472 if (!vga_arbiter_used) 1473 return; 1474 1475 spin_lock_irqsave(&vga_lock, flags); 1476 list_for_each_entry(vgadev, &vga_list, list) { 1477 if (vga_count > 1) 1478 new_state = false; 1479 else 1480 new_state = true; 1481 if (vgadev->set_decode) { 1482 new_decodes = vgadev->set_decode(vgadev->pdev, 1483 new_state); 1484 vga_update_device_decodes(vgadev, new_decodes); 1485 } 1486 } 1487 spin_unlock_irqrestore(&vga_lock, flags); 1488 } 1489 1490 static int pci_notify(struct notifier_block *nb, unsigned long action, 1491 void *data) 1492 { 1493 struct device *dev = data; 1494 struct pci_dev *pdev = to_pci_dev(dev); 1495 bool notify = false; 1496 1497 vgaarb_dbg(dev, "%s\n", __func__); 1498 1499 /* For now we're only intereted in devices added and removed. I didn't 1500 * test this thing here, so someone needs to double check for the 1501 * cases of hotplugable vga cards. */ 1502 if (action == BUS_NOTIFY_ADD_DEVICE) 1503 notify = vga_arbiter_add_pci_device(pdev); 1504 else if (action == BUS_NOTIFY_DEL_DEVICE) 1505 notify = vga_arbiter_del_pci_device(pdev); 1506 1507 if (notify) 1508 vga_arbiter_notify_clients(); 1509 return 0; 1510 } 1511 1512 static struct notifier_block pci_notifier = { 1513 .notifier_call = pci_notify, 1514 }; 1515 1516 static const struct file_operations vga_arb_device_fops = { 1517 .read = vga_arb_read, 1518 .write = vga_arb_write, 1519 .poll = vga_arb_fpoll, 1520 .open = vga_arb_open, 1521 .release = vga_arb_release, 1522 .llseek = noop_llseek, 1523 }; 1524 1525 static struct miscdevice vga_arb_device = { 1526 MISC_DYNAMIC_MINOR, "vga_arbiter", &vga_arb_device_fops 1527 }; 1528 1529 static void __init vga_arb_select_default_device(void) 1530 { 1531 struct pci_dev *pdev, *found = NULL; 1532 struct vga_device *vgadev; 1533 1534 list_for_each_entry(vgadev, &vga_list, list) { 1535 vga_select_framebuffer_device(vgadev->pdev); 1536 } 1537 1538 if (!vga_default_device()) { 1539 list_for_each_entry_reverse(vgadev, &vga_list, list) { 1540 struct device *dev = &vgadev->pdev->dev; 1541 u16 cmd; 1542 1543 pdev = vgadev->pdev; 1544 pci_read_config_word(pdev, PCI_COMMAND, &cmd); 1545 if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) { 1546 found = pdev; 1547 if (vga_arb_integrated_gpu(dev)) 1548 break; 1549 } 1550 } 1551 } 1552 1553 if (found) { 1554 vgaarb_info(&found->dev, "setting as boot device (VGA legacy resources not available)\n"); 1555 vga_set_default_device(found); 1556 return; 1557 } 1558 1559 if (!vga_default_device()) { 1560 vgadev = list_first_entry_or_null(&vga_list, 1561 struct vga_device, list); 1562 if (vgadev) { 1563 struct device *dev = &vgadev->pdev->dev; 1564 vgaarb_info(dev, "setting as boot device (VGA legacy resources not available)\n"); 1565 vga_set_default_device(vgadev->pdev); 1566 } 1567 } 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 vga_arb_select_default_device(); 1600 1601 pr_info("loaded\n"); 1602 return rc; 1603 } 1604 subsys_initcall_sync(vga_arb_device_init); 1605