1// SPDX-License-Identifier: MIT 2/* 3 * vgaarb.c: Implements VGA arbitration. For details refer to 4 * Documentation/gpu/vgaarbiter.rst 5 * 6 * (C) Copyright 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org> 7 * (C) Copyright 2007 Paulo R. Zanoni <przanoni@gmail.com> 8 * (C) Copyright 2007, 2009 Tiago Vignatti <vignatti@freedesktop.org> 9 */ 10 11#define pr_fmt(fmt) "vgaarb: " fmt 12 13#define vgaarb_dbg(dev, fmt, arg...) dev_dbg(dev, "vgaarb: " fmt, ##arg) 14#define vgaarb_info(dev, fmt, arg...) dev_info(dev, "vgaarb: " fmt, ##arg) 15#define vgaarb_err(dev, fmt, arg...) dev_err(dev, "vgaarb: " fmt, ##arg) 16 17#include <linux/module.h> 18#include <linux/kernel.h> 19#include <linux/pci.h> 20#include <linux/errno.h> 21#include <linux/init.h> 22#include <linux/list.h> 23#include <linux/sched/signal.h> 24#include <linux/wait.h> 25#include <linux/spinlock.h> 26#include <linux/poll.h> 27#include <linux/miscdevice.h> 28#include <linux/slab.h> 29#include <linux/screen_info.h> 30#include <linux/vt.h> 31#include <linux/console.h> 32#include <linux/acpi.h> 33#include <linux/uaccess.h> 34#include <linux/vgaarb.h> 35 36static void vga_arbiter_notify_clients(void); 37 38/* 39 * We keep a list of all VGA devices in the system to speed 40 * up the various operations of the arbiter 41 */ 42struct vga_device { 43 struct list_head list; 44 struct pci_dev *pdev; 45 unsigned int decodes; /* what it decodes */ 46 unsigned int owns; /* what it owns */ 47 unsigned int locks; /* what it locks */ 48 unsigned int io_lock_cnt; /* legacy IO lock count */ 49 unsigned int mem_lock_cnt; /* legacy MEM lock count */ 50 unsigned int io_norm_cnt; /* normal IO count */ 51 unsigned int mem_norm_cnt; /* normal MEM count */ 52 bool bridge_has_one_vga; 53 bool is_firmware_default; /* device selected by firmware */ 54 unsigned int (*set_decode)(struct pci_dev *pdev, bool decode); 55}; 56 57static LIST_HEAD(vga_list); 58static int vga_count, vga_decode_count; 59static bool vga_arbiter_used; 60static DEFINE_SPINLOCK(vga_lock); 61static DECLARE_WAIT_QUEUE_HEAD(vga_wait_queue); 62 63static const char *vga_iostate_to_str(unsigned int iostate) 64{ 65 /* Ignore VGA_RSRC_IO and VGA_RSRC_MEM */ 66 iostate &= VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; 67 switch (iostate) { 68 case VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM: 69 return "io+mem"; 70 case VGA_RSRC_LEGACY_IO: 71 return "io"; 72 case VGA_RSRC_LEGACY_MEM: 73 return "mem"; 74 } 75 return "none"; 76} 77 78static int vga_str_to_iostate(char *buf, int str_size, unsigned int *io_state) 79{ 80 /* 81 * In theory, we could hand out locks on IO and MEM separately to 82 * userspace, but this can cause deadlocks. 83 */ 84 if (strncmp(buf, "none", 4) == 0) { 85 *io_state = VGA_RSRC_NONE; 86 return 1; 87 } 88 89 /* XXX We're not checking the str_size! */ 90 if (strncmp(buf, "io+mem", 6) == 0) 91 goto both; 92 else if (strncmp(buf, "io", 2) == 0) 93 goto both; 94 else if (strncmp(buf, "mem", 3) == 0) 95 goto both; 96 return 0; 97both: 98 *io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; 99 return 1; 100} 101 102/* This is only used as a cookie, it should not be dereferenced */ 103static struct pci_dev *vga_default; 104 105/* Find somebody in our list */ 106static struct vga_device *vgadev_find(struct pci_dev *pdev) 107{ 108 struct vga_device *vgadev; 109 110 list_for_each_entry(vgadev, &vga_list, list) 111 if (pdev == vgadev->pdev) 112 return vgadev; 113 return NULL; 114} 115 116/** 117 * vga_default_device - return the default VGA device, for vgacon 118 * 119 * This can be defined by the platform. The default implementation is 120 * rather dumb and will probably only work properly on single VGA card 121 * setups and/or x86 platforms. 122 * 123 * If your VGA default device is not PCI, you'll have to return NULL here. 124 * In this case, I assume it will not conflict with any PCI card. If this 125 * is not true, I'll have to define two arch hooks for enabling/disabling 126 * the VGA default device if that is possible. This may be a problem with 127 * real _ISA_ VGA cards, in addition to a PCI one. I don't know at this 128 * point how to deal with that card. Can their IOs be disabled at all? If 129 * not, then I suppose it's a matter of having the proper arch hook telling 130 * us about it, so we basically never allow anybody to succeed a vga_get(). 131 */ 132struct pci_dev *vga_default_device(void) 133{ 134 return vga_default; 135} 136EXPORT_SYMBOL_GPL(vga_default_device); 137 138void vga_set_default_device(struct pci_dev *pdev) 139{ 140 if (vga_default == pdev) 141 return; 142 143 pci_dev_put(vga_default); 144 vga_default = pci_dev_get(pdev); 145} 146 147/** 148 * vga_remove_vgacon - deactivate VGA console 149 * 150 * Unbind and unregister vgacon in case pdev is the default VGA device. 151 * Can be called by GPU drivers on initialization to make sure VGA register 152 * access done by vgacon will not disturb the device. 153 * 154 * @pdev: PCI device. 155 */ 156#if !defined(CONFIG_VGA_CONSOLE) 157int vga_remove_vgacon(struct pci_dev *pdev) 158{ 159 return 0; 160} 161#elif !defined(CONFIG_DUMMY_CONSOLE) 162int vga_remove_vgacon(struct pci_dev *pdev) 163{ 164 return -ENODEV; 165} 166#else 167int vga_remove_vgacon(struct pci_dev *pdev) 168{ 169 int ret = 0; 170 171 if (pdev != vga_default) 172 return 0; 173 vgaarb_info(&pdev->dev, "deactivate vga console\n"); 174 175 console_lock(); 176 if (con_is_bound(&vga_con)) 177 ret = do_take_over_console(&dummy_con, 0, 178 MAX_NR_CONSOLES - 1, 1); 179 if (ret == 0) { 180 ret = do_unregister_con_driver(&vga_con); 181 182 /* Ignore "already unregistered". */ 183 if (ret == -ENODEV) 184 ret = 0; 185 } 186 console_unlock(); 187 188 return ret; 189} 190#endif 191EXPORT_SYMBOL(vga_remove_vgacon); 192 193/* 194 * If we don't ever use VGA arbitration, we should avoid turning off 195 * anything anywhere due to old X servers getting confused about the boot 196 * device not being VGA. 197 */ 198static void vga_check_first_use(void) 199{ 200 /* 201 * Inform all GPUs in the system that VGA arbitration has occurred 202 * so they can disable resources if possible. 203 */ 204 if (!vga_arbiter_used) { 205 vga_arbiter_used = true; 206 vga_arbiter_notify_clients(); 207 } 208} 209 210static struct vga_device *__vga_tryget(struct vga_device *vgadev, 211 unsigned int rsrc) 212{ 213 struct device *dev = &vgadev->pdev->dev; 214 unsigned int wants, legacy_wants, match; 215 struct vga_device *conflict; 216 unsigned int pci_bits; 217 u32 flags = 0; 218 219 /* 220 * Account for "normal" resources to lock. If we decode the legacy, 221 * counterpart, we need to request it as well 222 */ 223 if ((rsrc & VGA_RSRC_NORMAL_IO) && 224 (vgadev->decodes & VGA_RSRC_LEGACY_IO)) 225 rsrc |= VGA_RSRC_LEGACY_IO; 226 if ((rsrc & VGA_RSRC_NORMAL_MEM) && 227 (vgadev->decodes & VGA_RSRC_LEGACY_MEM)) 228 rsrc |= VGA_RSRC_LEGACY_MEM; 229 230 vgaarb_dbg(dev, "%s: %d\n", __func__, rsrc); 231 vgaarb_dbg(dev, "%s: owns: %d\n", __func__, vgadev->owns); 232 233 /* Check what resources we need to acquire */ 234 wants = rsrc & ~vgadev->owns; 235 236 /* We already own everything, just mark locked & bye bye */ 237 if (wants == 0) 238 goto lock_them; 239 240 /* 241 * We don't need to request a legacy resource, we just enable 242 * appropriate decoding and go. 243 */ 244 legacy_wants = wants & VGA_RSRC_LEGACY_MASK; 245 if (legacy_wants == 0) 246 goto enable_them; 247 248 /* Ok, we don't, let's find out who we need to kick off */ 249 list_for_each_entry(conflict, &vga_list, list) { 250 unsigned int lwants = legacy_wants; 251 unsigned int change_bridge = 0; 252 253 /* Don't conflict with myself */ 254 if (vgadev == conflict) 255 continue; 256 257 /* 258 * We have a possible conflict. Before we go further, we must 259 * check if we sit on the same bus as the conflicting device. 260 * If we don't, then we must tie both IO and MEM resources 261 * together since there is only a single bit controlling 262 * VGA forwarding on P2P bridges. 263 */ 264 if (vgadev->pdev->bus != conflict->pdev->bus) { 265 change_bridge = 1; 266 lwants = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; 267 } 268 269 /* 270 * Check if the guy has a lock on the resource. If he does, 271 * return the conflicting entry. 272 */ 273 if (conflict->locks & lwants) 274 return conflict; 275 276 /* 277 * Ok, now check if it owns the resource we want. We can 278 * lock resources that are not decoded; therefore a device 279 * can own resources it doesn't decode. 280 */ 281 match = lwants & conflict->owns; 282 if (!match) 283 continue; 284 285 /* 286 * Looks like he doesn't have a lock, we can steal them 287 * from him. 288 */ 289 290 flags = 0; 291 pci_bits = 0; 292 293 /* 294 * If we can't control legacy resources via the bridge, we 295 * also need to disable normal decoding. 296 */ 297 if (!conflict->bridge_has_one_vga) { 298 if ((match & conflict->decodes) & VGA_RSRC_LEGACY_MEM) 299 pci_bits |= PCI_COMMAND_MEMORY; 300 if ((match & conflict->decodes) & VGA_RSRC_LEGACY_IO) 301 pci_bits |= PCI_COMMAND_IO; 302 303 if (pci_bits) 304 flags |= PCI_VGA_STATE_CHANGE_DECODES; 305 } 306 307 if (change_bridge) 308 flags |= PCI_VGA_STATE_CHANGE_BRIDGE; 309 310 pci_set_vga_state(conflict->pdev, false, pci_bits, flags); 311 conflict->owns &= ~match; 312 313 /* If we disabled normal decoding, reflect it in owns */ 314 if (pci_bits & PCI_COMMAND_MEMORY) 315 conflict->owns &= ~VGA_RSRC_NORMAL_MEM; 316 if (pci_bits & PCI_COMMAND_IO) 317 conflict->owns &= ~VGA_RSRC_NORMAL_IO; 318 } 319 320enable_them: 321 /* 322 * Ok, we got it, everybody conflicting has been disabled, let's 323 * enable us. Mark any bits in "owns" regardless of whether we 324 * decoded them. We can lock resources we don't decode, therefore 325 * we must track them via "owns". 326 */ 327 flags = 0; 328 pci_bits = 0; 329 330 if (!vgadev->bridge_has_one_vga) { 331 flags |= PCI_VGA_STATE_CHANGE_DECODES; 332 if (wants & (VGA_RSRC_LEGACY_MEM|VGA_RSRC_NORMAL_MEM)) 333 pci_bits |= PCI_COMMAND_MEMORY; 334 if (wants & (VGA_RSRC_LEGACY_IO|VGA_RSRC_NORMAL_IO)) 335 pci_bits |= PCI_COMMAND_IO; 336 } 337 if (wants & VGA_RSRC_LEGACY_MASK) 338 flags |= PCI_VGA_STATE_CHANGE_BRIDGE; 339 340 pci_set_vga_state(vgadev->pdev, true, pci_bits, flags); 341 342 vgadev->owns |= wants; 343lock_them: 344 vgadev->locks |= (rsrc & VGA_RSRC_LEGACY_MASK); 345 if (rsrc & VGA_RSRC_LEGACY_IO) 346 vgadev->io_lock_cnt++; 347 if (rsrc & VGA_RSRC_LEGACY_MEM) 348 vgadev->mem_lock_cnt++; 349 if (rsrc & VGA_RSRC_NORMAL_IO) 350 vgadev->io_norm_cnt++; 351 if (rsrc & VGA_RSRC_NORMAL_MEM) 352 vgadev->mem_norm_cnt++; 353 354 return NULL; 355} 356 357static void __vga_put(struct vga_device *vgadev, unsigned int rsrc) 358{ 359 struct device *dev = &vgadev->pdev->dev; 360 unsigned int old_locks = vgadev->locks; 361 362 vgaarb_dbg(dev, "%s\n", __func__); 363 364 /* 365 * Update our counters and account for equivalent legacy resources 366 * if we decode them. 367 */ 368 if ((rsrc & VGA_RSRC_NORMAL_IO) && vgadev->io_norm_cnt > 0) { 369 vgadev->io_norm_cnt--; 370 if (vgadev->decodes & VGA_RSRC_LEGACY_IO) 371 rsrc |= VGA_RSRC_LEGACY_IO; 372 } 373 if ((rsrc & VGA_RSRC_NORMAL_MEM) && vgadev->mem_norm_cnt > 0) { 374 vgadev->mem_norm_cnt--; 375 if (vgadev->decodes & VGA_RSRC_LEGACY_MEM) 376 rsrc |= VGA_RSRC_LEGACY_MEM; 377 } 378 if ((rsrc & VGA_RSRC_LEGACY_IO) && vgadev->io_lock_cnt > 0) 379 vgadev->io_lock_cnt--; 380 if ((rsrc & VGA_RSRC_LEGACY_MEM) && vgadev->mem_lock_cnt > 0) 381 vgadev->mem_lock_cnt--; 382 383 /* 384 * Just clear lock bits, we do lazy operations so we don't really 385 * have to bother about anything else at this point. 386 */ 387 if (vgadev->io_lock_cnt == 0) 388 vgadev->locks &= ~VGA_RSRC_LEGACY_IO; 389 if (vgadev->mem_lock_cnt == 0) 390 vgadev->locks &= ~VGA_RSRC_LEGACY_MEM; 391 392 /* 393 * Kick the wait queue in case somebody was waiting if we actually 394 * released something. 395 */ 396 if (old_locks != vgadev->locks) 397 wake_up_all(&vga_wait_queue); 398} 399 400/** 401 * vga_get - acquire & lock VGA resources 402 * @pdev: PCI device of the VGA card or NULL for the system default 403 * @rsrc: bit mask of resources to acquire and lock 404 * @interruptible: blocking should be interruptible by signals ? 405 * 406 * Acquire VGA resources for the given card and mark those resources 407 * locked. If the resources requested are "normal" (and not legacy) 408 * resources, the arbiter will first check whether the card is doing legacy 409 * decoding for that type of resource. If yes, the lock is "converted" into 410 * a legacy resource lock. 411 * 412 * The arbiter will first look for all VGA cards that might conflict and disable 413 * their IOs and/or Memory access, including VGA forwarding on P2P bridges if 414 * necessary, so that the requested resources can be used. Then, the card is 415 * marked as locking these resources and the IO and/or Memory accesses are 416 * enabled on the card (including VGA forwarding on parent P2P bridges if any). 417 * 418 * This function will block if some conflicting card is already locking one of 419 * the required resources (or any resource on a different bus segment, since P2P 420 * bridges don't differentiate VGA memory and IO afaik). You can indicate 421 * whether this blocking should be interruptible by a signal (for userland 422 * interface) or not. 423 * 424 * Must not be called at interrupt time or in atomic context. If the card 425 * already owns the resources, the function succeeds. Nested calls are 426 * supported (a per-resource counter is maintained) 427 * 428 * On success, release the VGA resource again with vga_put(). 429 * 430 * Returns: 431 * 432 * 0 on success, negative error code on failure. 433 */ 434int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible) 435{ 436 struct vga_device *vgadev, *conflict; 437 unsigned long flags; 438 wait_queue_entry_t wait; 439 int rc = 0; 440 441 vga_check_first_use(); 442 /* The caller should check for this, but let's be sure */ 443 if (pdev == NULL) 444 pdev = vga_default_device(); 445 if (pdev == NULL) 446 return 0; 447 448 for (;;) { 449 spin_lock_irqsave(&vga_lock, flags); 450 vgadev = vgadev_find(pdev); 451 if (vgadev == NULL) { 452 spin_unlock_irqrestore(&vga_lock, flags); 453 rc = -ENODEV; 454 break; 455 } 456 conflict = __vga_tryget(vgadev, rsrc); 457 spin_unlock_irqrestore(&vga_lock, flags); 458 if (conflict == NULL) 459 break; 460 461 /* 462 * We have a conflict; we wait until somebody kicks the 463 * work queue. Currently we have one work queue that we 464 * kick each time some resources are released, but it would 465 * be fairly easy to have a per-device one so that we only 466 * need to attach to the conflicting device. 467 */ 468 init_waitqueue_entry(&wait, current); 469 add_wait_queue(&vga_wait_queue, &wait); 470 set_current_state(interruptible ? 471 TASK_INTERRUPTIBLE : 472 TASK_UNINTERRUPTIBLE); 473 if (interruptible && signal_pending(current)) { 474 __set_current_state(TASK_RUNNING); 475 remove_wait_queue(&vga_wait_queue, &wait); 476 rc = -ERESTARTSYS; 477 break; 478 } 479 schedule(); 480 remove_wait_queue(&vga_wait_queue, &wait); 481 } 482 return rc; 483} 484EXPORT_SYMBOL(vga_get); 485 486/** 487 * vga_tryget - try to acquire & lock legacy VGA resources 488 * @pdev: PCI device of VGA card or NULL for system default 489 * @rsrc: bit mask of resources to acquire and lock 490 * 491 * Perform the same operation as vga_get(), but return an error (-EBUSY) 492 * instead of blocking if the resources are already locked by another card. 493 * Can be called in any context. 494 * 495 * On success, release the VGA resource again with vga_put(). 496 * 497 * Returns: 498 * 499 * 0 on success, negative error code on failure. 500 */ 501static int vga_tryget(struct pci_dev *pdev, unsigned int rsrc) 502{ 503 struct vga_device *vgadev; 504 unsigned long flags; 505 int rc = 0; 506 507 vga_check_first_use(); 508 509 /* The caller should check for this, but let's be sure */ 510 if (pdev == NULL) 511 pdev = vga_default_device(); 512 if (pdev == NULL) 513 return 0; 514 spin_lock_irqsave(&vga_lock, flags); 515 vgadev = vgadev_find(pdev); 516 if (vgadev == NULL) { 517 rc = -ENODEV; 518 goto bail; 519 } 520 if (__vga_tryget(vgadev, rsrc)) 521 rc = -EBUSY; 522bail: 523 spin_unlock_irqrestore(&vga_lock, flags); 524 return rc; 525} 526 527/** 528 * vga_put - release lock on legacy VGA resources 529 * @pdev: PCI device of VGA card or NULL for system default 530 * @rsrc: bit mask of resource to release 531 * 532 * Release resources previously locked by vga_get() or vga_tryget(). The 533 * resources aren't disabled right away, so that a subsequent vga_get() on 534 * the same card will succeed immediately. Resources have a counter, so 535 * locks are only released if the counter reaches 0. 536 */ 537void vga_put(struct pci_dev *pdev, unsigned int rsrc) 538{ 539 struct vga_device *vgadev; 540 unsigned long flags; 541 542 /* The caller should check for this, but let's be sure */ 543 if (pdev == NULL) 544 pdev = vga_default_device(); 545 if (pdev == NULL) 546 return; 547 spin_lock_irqsave(&vga_lock, flags); 548 vgadev = vgadev_find(pdev); 549 if (vgadev == NULL) 550 goto bail; 551 __vga_put(vgadev, rsrc); 552bail: 553 spin_unlock_irqrestore(&vga_lock, flags); 554} 555EXPORT_SYMBOL(vga_put); 556 557static bool vga_is_firmware_default(struct pci_dev *pdev) 558{ 559#if defined(CONFIG_X86) || defined(CONFIG_IA64) 560 u64 base = screen_info.lfb_base; 561 u64 size = screen_info.lfb_size; 562 struct resource *r; 563 u64 limit; 564 565 /* Select the device owning the boot framebuffer if there is one */ 566 567 if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) 568 base |= (u64)screen_info.ext_lfb_base << 32; 569 570 limit = base + size; 571 572 /* Does firmware framebuffer belong to us? */ 573 pci_dev_for_each_resource(pdev, r) { 574 if (resource_type(r) != IORESOURCE_MEM) 575 continue; 576 577 if (!r->start || !r->end) 578 continue; 579 580 if (base < r->start || limit >= r->end) 581 continue; 582 583 return true; 584 } 585#endif 586 return false; 587} 588 589static bool vga_arb_integrated_gpu(struct device *dev) 590{ 591#if defined(CONFIG_ACPI) 592 struct acpi_device *adev = ACPI_COMPANION(dev); 593 594 return adev && !strcmp(acpi_device_hid(adev), ACPI_VIDEO_HID); 595#else 596 return false; 597#endif 598} 599 600/* 601 * Return true if vgadev is a better default VGA device than the best one 602 * we've seen so far. 603 */ 604static bool vga_is_boot_device(struct vga_device *vgadev) 605{ 606 struct vga_device *boot_vga = vgadev_find(vga_default_device()); 607 struct pci_dev *pdev = vgadev->pdev; 608 u16 cmd, boot_cmd; 609 610 /* 611 * We select the default VGA device in this order: 612 * Firmware framebuffer (see vga_arb_select_default_device()) 613 * Legacy VGA device (owns VGA_RSRC_LEGACY_MASK) 614 * Non-legacy integrated device (see vga_arb_select_default_device()) 615 * Non-legacy discrete device (see vga_arb_select_default_device()) 616 * Other device (see vga_arb_select_default_device()) 617 */ 618 619 /* 620 * We always prefer a firmware default device, so if we've already 621 * found one, there's no need to consider vgadev. 622 */ 623 if (boot_vga && boot_vga->is_firmware_default) 624 return false; 625 626 if (vga_is_firmware_default(pdev)) { 627 vgadev->is_firmware_default = true; 628 return true; 629 } 630 631 /* 632 * A legacy VGA device has MEM and IO enabled and any bridges 633 * leading to it have PCI_BRIDGE_CTL_VGA enabled so the legacy 634 * resources ([mem 0xa0000-0xbffff], [io 0x3b0-0x3bb], etc) are 635 * routed to it. 636 * 637 * We use the first one we find, so if we've already found one, 638 * vgadev is no better. 639 */ 640 if (boot_vga && 641 (boot_vga->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK) 642 return false; 643 644 if ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK) 645 return true; 646 647 /* 648 * If we haven't found a legacy VGA device, accept a non-legacy 649 * device. It may have either IO or MEM enabled, and bridges may 650 * not have PCI_BRIDGE_CTL_VGA enabled, so it may not be able to 651 * use legacy VGA resources. Prefer an integrated GPU over others. 652 */ 653 pci_read_config_word(pdev, PCI_COMMAND, &cmd); 654 if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) { 655 656 /* 657 * An integrated GPU overrides a previous non-legacy 658 * device. We expect only a single integrated GPU, but if 659 * there are more, we use the *last* because that was the 660 * previous behavior. 661 */ 662 if (vga_arb_integrated_gpu(&pdev->dev)) 663 return true; 664 665 /* 666 * We prefer the first non-legacy discrete device we find. 667 * If we already found one, vgadev is no better. 668 */ 669 if (boot_vga) { 670 pci_read_config_word(boot_vga->pdev, PCI_COMMAND, 671 &boot_cmd); 672 if (boot_cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) 673 return false; 674 } 675 return true; 676 } 677 678 /* 679 * Vgadev has neither IO nor MEM enabled. If we haven't found any 680 * other VGA devices, it is the best candidate so far. 681 */ 682 if (!boot_vga) 683 return true; 684 685 return false; 686} 687 688/* 689 * Rules for using a bridge to control a VGA descendant decoding: if a bridge 690 * has only one VGA descendant then it can be used to control the VGA routing 691 * for that device. It should always use the bridge closest to the device to 692 * control it. If a bridge has a direct VGA descendant, but also have a sub- 693 * bridge VGA descendant then we cannot use that bridge to control the direct 694 * VGA descendant. So for every device we register, we need to iterate all 695 * its parent bridges so we can invalidate any devices using them properly. 696 */ 697static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev) 698{ 699 struct vga_device *same_bridge_vgadev; 700 struct pci_bus *new_bus, *bus; 701 struct pci_dev *new_bridge, *bridge; 702 703 vgadev->bridge_has_one_vga = true; 704 705 if (list_empty(&vga_list)) { 706 vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n"); 707 return; 708 } 709 710 /* Iterate the new device's bridge hierarchy */ 711 new_bus = vgadev->pdev->bus; 712 while (new_bus) { 713 new_bridge = new_bus->self; 714 715 /* Go through list of devices already registered */ 716 list_for_each_entry(same_bridge_vgadev, &vga_list, list) { 717 bus = same_bridge_vgadev->pdev->bus; 718 bridge = bus->self; 719 720 /* See if it shares a bridge with this device */ 721 if (new_bridge == bridge) { 722 /* 723 * If its direct parent bridge is the same 724 * as any bridge of this device then it can't 725 * be used for that device. 726 */ 727 same_bridge_vgadev->bridge_has_one_vga = false; 728 } 729 730 /* 731 * Now iterate the previous device's bridge hierarchy. 732 * If the new device's parent bridge is in the other 733 * device's hierarchy, we can't use it to control this 734 * device. 735 */ 736 while (bus) { 737 bridge = bus->self; 738 739 if (bridge && bridge == vgadev->pdev->bus->self) 740 vgadev->bridge_has_one_vga = false; 741 742 bus = bus->parent; 743 } 744 } 745 new_bus = new_bus->parent; 746 } 747 748 if (vgadev->bridge_has_one_vga) 749 vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n"); 750 else 751 vgaarb_info(&vgadev->pdev->dev, "no bridge control possible\n"); 752} 753 754/* 755 * Currently, we assume that the "initial" setup of the system is not sane, 756 * that is, we come up with conflicting devices and let the arbiter's 757 * client decide if devices decodes legacy things or not. 758 */ 759static bool vga_arbiter_add_pci_device(struct pci_dev *pdev) 760{ 761 struct vga_device *vgadev; 762 unsigned long flags; 763 struct pci_bus *bus; 764 struct pci_dev *bridge; 765 u16 cmd; 766 767 /* Only deal with VGA class devices */ 768 if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA) 769 return false; 770 771 /* Allocate structure */ 772 vgadev = kzalloc(sizeof(struct vga_device), GFP_KERNEL); 773 if (vgadev == NULL) { 774 vgaarb_err(&pdev->dev, "failed to allocate VGA arbiter data\n"); 775 /* 776 * What to do on allocation failure? For now, let's just do 777 * nothing, I'm not sure there is anything saner to be done. 778 */ 779 return false; 780 } 781 782 /* Take lock & check for duplicates */ 783 spin_lock_irqsave(&vga_lock, flags); 784 if (vgadev_find(pdev) != NULL) { 785 BUG_ON(1); 786 goto fail; 787 } 788 vgadev->pdev = pdev; 789 790 /* By default, assume we decode everything */ 791 vgadev->decodes = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM | 792 VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM; 793 794 /* By default, mark it as decoding */ 795 vga_decode_count++; 796 797 /* 798 * Mark that we "own" resources based on our enables, we will 799 * clear that below if the bridge isn't forwarding. 800 */ 801 pci_read_config_word(pdev, PCI_COMMAND, &cmd); 802 if (cmd & PCI_COMMAND_IO) 803 vgadev->owns |= VGA_RSRC_LEGACY_IO; 804 if (cmd & PCI_COMMAND_MEMORY) 805 vgadev->owns |= VGA_RSRC_LEGACY_MEM; 806 807 /* Check if VGA cycles can get down to us */ 808 bus = pdev->bus; 809 while (bus) { 810 bridge = bus->self; 811 if (bridge) { 812 u16 l; 813 814 pci_read_config_word(bridge, PCI_BRIDGE_CONTROL, &l); 815 if (!(l & PCI_BRIDGE_CTL_VGA)) { 816 vgadev->owns = 0; 817 break; 818 } 819 } 820 bus = bus->parent; 821 } 822 823 if (vga_is_boot_device(vgadev)) { 824 vgaarb_info(&pdev->dev, "setting as boot VGA device%s\n", 825 vga_default_device() ? 826 " (overriding previous)" : ""); 827 vga_set_default_device(pdev); 828 } 829 830 vga_arbiter_check_bridge_sharing(vgadev); 831 832 /* Add to the list */ 833 list_add_tail(&vgadev->list, &vga_list); 834 vga_count++; 835 vgaarb_info(&pdev->dev, "VGA device added: decodes=%s,owns=%s,locks=%s\n", 836 vga_iostate_to_str(vgadev->decodes), 837 vga_iostate_to_str(vgadev->owns), 838 vga_iostate_to_str(vgadev->locks)); 839 840 spin_unlock_irqrestore(&vga_lock, flags); 841 return true; 842fail: 843 spin_unlock_irqrestore(&vga_lock, flags); 844 kfree(vgadev); 845 return false; 846} 847 848static bool vga_arbiter_del_pci_device(struct pci_dev *pdev) 849{ 850 struct vga_device *vgadev; 851 unsigned long flags; 852 bool ret = true; 853 854 spin_lock_irqsave(&vga_lock, flags); 855 vgadev = vgadev_find(pdev); 856 if (vgadev == NULL) { 857 ret = false; 858 goto bail; 859 } 860 861 if (vga_default == pdev) 862 vga_set_default_device(NULL); 863 864 if (vgadev->decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM)) 865 vga_decode_count--; 866 867 /* Remove entry from list */ 868 list_del(&vgadev->list); 869 vga_count--; 870 871 /* Wake up all possible waiters */ 872 wake_up_all(&vga_wait_queue); 873bail: 874 spin_unlock_irqrestore(&vga_lock, flags); 875 kfree(vgadev); 876 return ret; 877} 878 879/* Called with the lock */ 880static void vga_update_device_decodes(struct vga_device *vgadev, 881 unsigned int new_decodes) 882{ 883 struct device *dev = &vgadev->pdev->dev; 884 unsigned int old_decodes = vgadev->decodes; 885 unsigned int decodes_removed = ~new_decodes & old_decodes; 886 unsigned int decodes_unlocked = vgadev->locks & decodes_removed; 887 888 vgadev->decodes = new_decodes; 889 890 vgaarb_info(dev, "VGA decodes changed: olddecodes=%s,decodes=%s:owns=%s\n", 891 vga_iostate_to_str(old_decodes), 892 vga_iostate_to_str(vgadev->decodes), 893 vga_iostate_to_str(vgadev->owns)); 894 895 /* If we removed locked decodes, lock count goes to zero, and release */ 896 if (decodes_unlocked) { 897 if (decodes_unlocked & VGA_RSRC_LEGACY_IO) 898 vgadev->io_lock_cnt = 0; 899 if (decodes_unlocked & VGA_RSRC_LEGACY_MEM) 900 vgadev->mem_lock_cnt = 0; 901 __vga_put(vgadev, decodes_unlocked); 902 } 903 904 /* Change decodes counter */ 905 if (old_decodes & VGA_RSRC_LEGACY_MASK && 906 !(new_decodes & VGA_RSRC_LEGACY_MASK)) 907 vga_decode_count--; 908 if (!(old_decodes & VGA_RSRC_LEGACY_MASK) && 909 new_decodes & VGA_RSRC_LEGACY_MASK) 910 vga_decode_count++; 911 vgaarb_dbg(dev, "decoding count now is: %d\n", vga_decode_count); 912} 913 914static void __vga_set_legacy_decoding(struct pci_dev *pdev, 915 unsigned int decodes, 916 bool userspace) 917{ 918 struct vga_device *vgadev; 919 unsigned long flags; 920 921 decodes &= VGA_RSRC_LEGACY_MASK; 922 923 spin_lock_irqsave(&vga_lock, flags); 924 vgadev = vgadev_find(pdev); 925 if (vgadev == NULL) 926 goto bail; 927 928 /* Don't let userspace futz with kernel driver decodes */ 929 if (userspace && vgadev->set_decode) 930 goto bail; 931 932 /* Update the device decodes + counter */ 933 vga_update_device_decodes(vgadev, decodes); 934 935 /* 936 * XXX If somebody is going from "doesn't decode" to "decodes" 937 * state here, additional care must be taken as we may have pending 938 * ownership of non-legacy region. 939 */ 940bail: 941 spin_unlock_irqrestore(&vga_lock, flags); 942} 943 944/** 945 * vga_set_legacy_decoding 946 * @pdev: PCI device of the VGA card 947 * @decodes: bit mask of what legacy regions the card decodes 948 * 949 * Indicate to the arbiter if the card decodes legacy VGA IOs, legacy VGA 950 * Memory, both, or none. All cards default to both, the card driver (fbdev for 951 * example) should tell the arbiter if it has disabled legacy decoding, so the 952 * card can be left out of the arbitration process (and can be safe to take 953 * interrupts at any time. 954 */ 955void vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes) 956{ 957 __vga_set_legacy_decoding(pdev, decodes, false); 958} 959EXPORT_SYMBOL(vga_set_legacy_decoding); 960 961/** 962 * vga_client_register - register or unregister a VGA arbitration client 963 * @pdev: PCI device of the VGA client 964 * @set_decode: VGA decode change callback 965 * 966 * Clients have two callback mechanisms they can use. 967 * 968 * @set_decode callback: If a client can disable its GPU VGA resource, it 969 * will get a callback from this to set the encode/decode state. 970 * 971 * Rationale: we cannot disable VGA decode resources unconditionally 972 * because some single GPU laptops seem to require ACPI or BIOS access to 973 * the VGA registers to control things like backlights etc. Hopefully newer 974 * multi-GPU laptops do something saner, and desktops won't have any 975 * special ACPI for this. The driver will get a callback when VGA 976 * arbitration is first used by userspace since some older X servers have 977 * issues. 978 * 979 * Does not check whether a client for @pdev has been registered already. 980 * 981 * To unregister, call vga_client_unregister(). 982 * 983 * Returns: 0 on success, -ENODEV on failure 984 */ 985int vga_client_register(struct pci_dev *pdev, 986 unsigned int (*set_decode)(struct pci_dev *pdev, bool decode)) 987{ 988 unsigned long flags; 989 struct vga_device *vgadev; 990 991 spin_lock_irqsave(&vga_lock, flags); 992 vgadev = vgadev_find(pdev); 993 if (vgadev) 994 vgadev->set_decode = set_decode; 995 spin_unlock_irqrestore(&vga_lock, flags); 996 if (!vgadev) 997 return -ENODEV; 998 return 0; 999} 1000EXPORT_SYMBOL(vga_client_register); 1001 1002/* 1003 * Char driver implementation 1004 * 1005 * Semantics is: 1006 * 1007 * open : Open user instance of the arbiter. By default, it's 1008 * attached to the default VGA device of the system. 1009 * 1010 * close : Close user instance, release locks 1011 * 1012 * read : Return a string indicating the status of the target. 1013 * An IO state string is of the form {io,mem,io+mem,none}, 1014 * mc and ic are respectively mem and io lock counts (for 1015 * debugging/diagnostic only). "decodes" indicate what the 1016 * card currently decodes, "owns" indicates what is currently 1017 * enabled on it, and "locks" indicates what is locked by this 1018 * card. If the card is unplugged, we get "invalid" then for 1019 * card_ID and an -ENODEV error is returned for any command 1020 * until a new card is targeted 1021 * 1022 * "<card_ID>,decodes=<io_state>,owns=<io_state>,locks=<io_state> (ic,mc)" 1023 * 1024 * write : write a command to the arbiter. List of commands is: 1025 * 1026 * target <card_ID> : switch target to card <card_ID> (see below) 1027 * lock <io_state> : acquire locks on target ("none" is invalid io_state) 1028 * trylock <io_state> : non-blocking acquire locks on target 1029 * unlock <io_state> : release locks on target 1030 * unlock all : release all locks on target held by this user 1031 * decodes <io_state> : set the legacy decoding attributes for the card 1032 * 1033 * poll : event if something change on any card (not just the target) 1034 * 1035 * card_ID is of the form "PCI:domain:bus:dev.fn". It can be set to "default" 1036 * to go back to the system default card (TODO: not implemented yet). 1037 * Currently, only PCI is supported as a prefix, but the userland API may 1038 * support other bus types in the future, even if the current kernel 1039 * implementation doesn't. 1040 * 1041 * Note about locks: 1042 * 1043 * The driver keeps track of which user has what locks on which card. It 1044 * supports stacking, like the kernel one. This complicates the implementation 1045 * a bit, but makes the arbiter more tolerant to userspace problems and able 1046 * to properly cleanup in all cases when a process dies. 1047 * Currently, a max of 16 cards simultaneously can have locks issued from 1048 * userspace for a given user (file descriptor instance) of the arbiter. 1049 * 1050 * If the device is hot-unplugged, there is a hook inside the module to notify 1051 * it being added/removed in the system and automatically added/removed in 1052 * the arbiter. 1053 */ 1054 1055#define MAX_USER_CARDS CONFIG_VGA_ARB_MAX_GPUS 1056#define PCI_INVALID_CARD ((struct pci_dev *)-1UL) 1057 1058/* Each user has an array of these, tracking which cards have locks */ 1059struct vga_arb_user_card { 1060 struct pci_dev *pdev; 1061 unsigned int mem_cnt; 1062 unsigned int io_cnt; 1063}; 1064 1065struct vga_arb_private { 1066 struct list_head list; 1067 struct pci_dev *target; 1068 struct vga_arb_user_card cards[MAX_USER_CARDS]; 1069 spinlock_t lock; 1070}; 1071 1072static LIST_HEAD(vga_user_list); 1073static DEFINE_SPINLOCK(vga_user_lock); 1074 1075 1076/* 1077 * Take a string in the format: "PCI:domain:bus:dev.fn" and return the 1078 * respective values. If the string is not in this format, return 0. 1079 */ 1080static int vga_pci_str_to_vars(char *buf, int count, unsigned int *domain, 1081 unsigned int *bus, unsigned int *devfn) 1082{ 1083 int n; 1084 unsigned int slot, func; 1085 1086 n = sscanf(buf, "PCI:%x:%x:%x.%x", domain, bus, &slot, &func); 1087 if (n != 4) 1088 return 0; 1089 1090 *devfn = PCI_DEVFN(slot, func); 1091 1092 return 1; 1093} 1094 1095static ssize_t vga_arb_read(struct file *file, char __user *buf, 1096 size_t count, loff_t *ppos) 1097{ 1098 struct vga_arb_private *priv = file->private_data; 1099 struct vga_device *vgadev; 1100 struct pci_dev *pdev; 1101 unsigned long flags; 1102 size_t len; 1103 int rc; 1104 char *lbuf; 1105 1106 lbuf = kmalloc(1024, GFP_KERNEL); 1107 if (lbuf == NULL) 1108 return -ENOMEM; 1109 1110 /* Protect vga_list */ 1111 spin_lock_irqsave(&vga_lock, flags); 1112 1113 /* If we are targeting the default, use it */ 1114 pdev = priv->target; 1115 if (pdev == NULL || pdev == PCI_INVALID_CARD) { 1116 spin_unlock_irqrestore(&vga_lock, flags); 1117 len = sprintf(lbuf, "invalid"); 1118 goto done; 1119 } 1120 1121 /* Find card vgadev structure */ 1122 vgadev = vgadev_find(pdev); 1123 if (vgadev == NULL) { 1124 /* 1125 * Wow, it's not in the list, that shouldn't happen, let's 1126 * fix us up and return invalid card. 1127 */ 1128 spin_unlock_irqrestore(&vga_lock, flags); 1129 len = sprintf(lbuf, "invalid"); 1130 goto done; 1131 } 1132 1133 /* Fill the buffer with info */ 1134 len = snprintf(lbuf, 1024, 1135 "count:%d,PCI:%s,decodes=%s,owns=%s,locks=%s(%u:%u)\n", 1136 vga_decode_count, pci_name(pdev), 1137 vga_iostate_to_str(vgadev->decodes), 1138 vga_iostate_to_str(vgadev->owns), 1139 vga_iostate_to_str(vgadev->locks), 1140 vgadev->io_lock_cnt, vgadev->mem_lock_cnt); 1141 1142 spin_unlock_irqrestore(&vga_lock, flags); 1143done: 1144 1145 /* Copy that to user */ 1146 if (len > count) 1147 len = count; 1148 rc = copy_to_user(buf, lbuf, len); 1149 kfree(lbuf); 1150 if (rc) 1151 return -EFAULT; 1152 return len; 1153} 1154 1155/* 1156 * TODO: To avoid parsing inside kernel and to improve the speed we may 1157 * consider use ioctl here 1158 */ 1159static ssize_t vga_arb_write(struct file *file, const char __user *buf, 1160 size_t count, loff_t *ppos) 1161{ 1162 struct vga_arb_private *priv = file->private_data; 1163 struct vga_arb_user_card *uc = NULL; 1164 struct pci_dev *pdev; 1165 1166 unsigned int io_state; 1167 1168 char kbuf[64], *curr_pos; 1169 size_t remaining = count; 1170 1171 int ret_val; 1172 int i; 1173 1174 if (count >= sizeof(kbuf)) 1175 return -EINVAL; 1176 if (copy_from_user(kbuf, buf, count)) 1177 return -EFAULT; 1178 curr_pos = kbuf; 1179 kbuf[count] = '\0'; 1180 1181 if (strncmp(curr_pos, "lock ", 5) == 0) { 1182 curr_pos += 5; 1183 remaining -= 5; 1184 1185 pr_debug("client 0x%p called 'lock'\n", priv); 1186 1187 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { 1188 ret_val = -EPROTO; 1189 goto done; 1190 } 1191 if (io_state == VGA_RSRC_NONE) { 1192 ret_val = -EPROTO; 1193 goto done; 1194 } 1195 1196 pdev = priv->target; 1197 if (priv->target == NULL) { 1198 ret_val = -ENODEV; 1199 goto done; 1200 } 1201 1202 vga_get_uninterruptible(pdev, io_state); 1203 1204 /* Update the client's locks lists */ 1205 for (i = 0; i < MAX_USER_CARDS; i++) { 1206 if (priv->cards[i].pdev == pdev) { 1207 if (io_state & VGA_RSRC_LEGACY_IO) 1208 priv->cards[i].io_cnt++; 1209 if (io_state & VGA_RSRC_LEGACY_MEM) 1210 priv->cards[i].mem_cnt++; 1211 break; 1212 } 1213 } 1214 1215 ret_val = count; 1216 goto done; 1217 } else if (strncmp(curr_pos, "unlock ", 7) == 0) { 1218 curr_pos += 7; 1219 remaining -= 7; 1220 1221 pr_debug("client 0x%p called 'unlock'\n", priv); 1222 1223 if (strncmp(curr_pos, "all", 3) == 0) 1224 io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; 1225 else { 1226 if (!vga_str_to_iostate 1227 (curr_pos, remaining, &io_state)) { 1228 ret_val = -EPROTO; 1229 goto done; 1230 } 1231 /* TODO: Add this? 1232 if (io_state == VGA_RSRC_NONE) { 1233 ret_val = -EPROTO; 1234 goto done; 1235 } 1236 */ 1237 } 1238 1239 pdev = priv->target; 1240 if (priv->target == NULL) { 1241 ret_val = -ENODEV; 1242 goto done; 1243 } 1244 for (i = 0; i < MAX_USER_CARDS; i++) { 1245 if (priv->cards[i].pdev == pdev) 1246 uc = &priv->cards[i]; 1247 } 1248 1249 if (!uc) { 1250 ret_val = -EINVAL; 1251 goto done; 1252 } 1253 1254 if (io_state & VGA_RSRC_LEGACY_IO && uc->io_cnt == 0) { 1255 ret_val = -EINVAL; 1256 goto done; 1257 } 1258 1259 if (io_state & VGA_RSRC_LEGACY_MEM && uc->mem_cnt == 0) { 1260 ret_val = -EINVAL; 1261 goto done; 1262 } 1263 1264 vga_put(pdev, io_state); 1265 1266 if (io_state & VGA_RSRC_LEGACY_IO) 1267 uc->io_cnt--; 1268 if (io_state & VGA_RSRC_LEGACY_MEM) 1269 uc->mem_cnt--; 1270 1271 ret_val = count; 1272 goto done; 1273 } else if (strncmp(curr_pos, "trylock ", 8) == 0) { 1274 curr_pos += 8; 1275 remaining -= 8; 1276 1277 pr_debug("client 0x%p called 'trylock'\n", priv); 1278 1279 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { 1280 ret_val = -EPROTO; 1281 goto done; 1282 } 1283 /* TODO: Add this? 1284 if (io_state == VGA_RSRC_NONE) { 1285 ret_val = -EPROTO; 1286 goto done; 1287 } 1288 */ 1289 1290 pdev = priv->target; 1291 if (priv->target == NULL) { 1292 ret_val = -ENODEV; 1293 goto done; 1294 } 1295 1296 if (vga_tryget(pdev, io_state)) { 1297 /* Update the client's locks lists... */ 1298 for (i = 0; i < MAX_USER_CARDS; i++) { 1299 if (priv->cards[i].pdev == pdev) { 1300 if (io_state & VGA_RSRC_LEGACY_IO) 1301 priv->cards[i].io_cnt++; 1302 if (io_state & VGA_RSRC_LEGACY_MEM) 1303 priv->cards[i].mem_cnt++; 1304 break; 1305 } 1306 } 1307 ret_val = count; 1308 goto done; 1309 } else { 1310 ret_val = -EBUSY; 1311 goto done; 1312 } 1313 1314 } else if (strncmp(curr_pos, "target ", 7) == 0) { 1315 unsigned int domain, bus, devfn; 1316 struct vga_device *vgadev; 1317 1318 curr_pos += 7; 1319 remaining -= 7; 1320 pr_debug("client 0x%p called 'target'\n", priv); 1321 /* If target is default */ 1322 if (!strncmp(curr_pos, "default", 7)) 1323 pdev = pci_dev_get(vga_default_device()); 1324 else { 1325 if (!vga_pci_str_to_vars(curr_pos, remaining, 1326 &domain, &bus, &devfn)) { 1327 ret_val = -EPROTO; 1328 goto done; 1329 } 1330 pdev = pci_get_domain_bus_and_slot(domain, bus, devfn); 1331 if (!pdev) { 1332 pr_debug("invalid PCI address %04x:%02x:%02x.%x\n", 1333 domain, bus, PCI_SLOT(devfn), 1334 PCI_FUNC(devfn)); 1335 ret_val = -ENODEV; 1336 goto done; 1337 } 1338 1339 pr_debug("%s ==> %04x:%02x:%02x.%x pdev %p\n", curr_pos, 1340 domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn), 1341 pdev); 1342 } 1343 1344 vgadev = vgadev_find(pdev); 1345 pr_debug("vgadev %p\n", vgadev); 1346 if (vgadev == NULL) { 1347 if (pdev) { 1348 vgaarb_dbg(&pdev->dev, "not a VGA device\n"); 1349 pci_dev_put(pdev); 1350 } 1351 1352 ret_val = -ENODEV; 1353 goto done; 1354 } 1355 1356 priv->target = pdev; 1357 for (i = 0; i < MAX_USER_CARDS; i++) { 1358 if (priv->cards[i].pdev == pdev) 1359 break; 1360 if (priv->cards[i].pdev == NULL) { 1361 priv->cards[i].pdev = pdev; 1362 priv->cards[i].io_cnt = 0; 1363 priv->cards[i].mem_cnt = 0; 1364 break; 1365 } 1366 } 1367 if (i == MAX_USER_CARDS) { 1368 vgaarb_dbg(&pdev->dev, "maximum user cards (%d) number reached, ignoring this one!\n", 1369 MAX_USER_CARDS); 1370 pci_dev_put(pdev); 1371 /* XXX: Which value to return? */ 1372 ret_val = -ENOMEM; 1373 goto done; 1374 } 1375 1376 ret_val = count; 1377 pci_dev_put(pdev); 1378 goto done; 1379 1380 1381 } else if (strncmp(curr_pos, "decodes ", 8) == 0) { 1382 curr_pos += 8; 1383 remaining -= 8; 1384 pr_debug("client 0x%p called 'decodes'\n", priv); 1385 1386 if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { 1387 ret_val = -EPROTO; 1388 goto done; 1389 } 1390 pdev = priv->target; 1391 if (priv->target == NULL) { 1392 ret_val = -ENODEV; 1393 goto done; 1394 } 1395 1396 __vga_set_legacy_decoding(pdev, io_state, true); 1397 ret_val = count; 1398 goto done; 1399 } 1400 /* If we got here, the message written is not part of the protocol! */ 1401 return -EPROTO; 1402 1403done: 1404 return ret_val; 1405} 1406 1407static __poll_t vga_arb_fpoll(struct file *file, poll_table *wait) 1408{ 1409 pr_debug("%s\n", __func__); 1410 1411 poll_wait(file, &vga_wait_queue, wait); 1412 return EPOLLIN; 1413} 1414 1415static int vga_arb_open(struct inode *inode, struct file *file) 1416{ 1417 struct vga_arb_private *priv; 1418 unsigned long flags; 1419 1420 pr_debug("%s\n", __func__); 1421 1422 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 1423 if (priv == NULL) 1424 return -ENOMEM; 1425 spin_lock_init(&priv->lock); 1426 file->private_data = priv; 1427 1428 spin_lock_irqsave(&vga_user_lock, flags); 1429 list_add(&priv->list, &vga_user_list); 1430 spin_unlock_irqrestore(&vga_user_lock, flags); 1431 1432 /* Set the client's lists of locks */ 1433 priv->target = vga_default_device(); /* Maybe this is still null! */ 1434 priv->cards[0].pdev = priv->target; 1435 priv->cards[0].io_cnt = 0; 1436 priv->cards[0].mem_cnt = 0; 1437 1438 return 0; 1439} 1440 1441static int vga_arb_release(struct inode *inode, struct file *file) 1442{ 1443 struct vga_arb_private *priv = file->private_data; 1444 struct vga_arb_user_card *uc; 1445 unsigned long flags; 1446 int i; 1447 1448 pr_debug("%s\n", __func__); 1449 1450 spin_lock_irqsave(&vga_user_lock, flags); 1451 list_del(&priv->list); 1452 for (i = 0; i < MAX_USER_CARDS; i++) { 1453 uc = &priv->cards[i]; 1454 if (uc->pdev == NULL) 1455 continue; 1456 vgaarb_dbg(&uc->pdev->dev, "uc->io_cnt == %d, uc->mem_cnt == %d\n", 1457 uc->io_cnt, uc->mem_cnt); 1458 while (uc->io_cnt--) 1459 vga_put(uc->pdev, VGA_RSRC_LEGACY_IO); 1460 while (uc->mem_cnt--) 1461 vga_put(uc->pdev, VGA_RSRC_LEGACY_MEM); 1462 } 1463 spin_unlock_irqrestore(&vga_user_lock, flags); 1464 1465 kfree(priv); 1466 1467 return 0; 1468} 1469 1470/* 1471 * Callback any registered clients to let them know we have a change in VGA 1472 * cards. 1473 */ 1474static void vga_arbiter_notify_clients(void) 1475{ 1476 struct vga_device *vgadev; 1477 unsigned long flags; 1478 unsigned int new_decodes; 1479 bool new_state; 1480 1481 if (!vga_arbiter_used) 1482 return; 1483 1484 new_state = (vga_count > 1) ? false : true; 1485 1486 spin_lock_irqsave(&vga_lock, flags); 1487 list_for_each_entry(vgadev, &vga_list, list) { 1488 if (vgadev->set_decode) { 1489 new_decodes = vgadev->set_decode(vgadev->pdev, 1490 new_state); 1491 vga_update_device_decodes(vgadev, new_decodes); 1492 } 1493 } 1494 spin_unlock_irqrestore(&vga_lock, flags); 1495} 1496 1497static int pci_notify(struct notifier_block *nb, unsigned long action, 1498 void *data) 1499{ 1500 struct device *dev = data; 1501 struct pci_dev *pdev = to_pci_dev(dev); 1502 bool notify = false; 1503 1504 vgaarb_dbg(dev, "%s\n", __func__); 1505 1506 /* 1507 * For now, we're only interested in devices added and removed. 1508 * I didn't test this thing here, so someone needs to double check 1509 * for the cases of hot-pluggable VGA cards. 1510 */ 1511 if (action == BUS_NOTIFY_ADD_DEVICE) 1512 notify = vga_arbiter_add_pci_device(pdev); 1513 else if (action == BUS_NOTIFY_DEL_DEVICE) 1514 notify = vga_arbiter_del_pci_device(pdev); 1515 1516 if (notify) 1517 vga_arbiter_notify_clients(); 1518 return 0; 1519} 1520 1521static struct notifier_block pci_notifier = { 1522 .notifier_call = pci_notify, 1523}; 1524 1525static const struct file_operations vga_arb_device_fops = { 1526 .read = vga_arb_read, 1527 .write = vga_arb_write, 1528 .poll = vga_arb_fpoll, 1529 .open = vga_arb_open, 1530 .release = vga_arb_release, 1531 .llseek = noop_llseek, 1532}; 1533 1534static struct miscdevice vga_arb_device = { 1535 MISC_DYNAMIC_MINOR, "vga_arbiter", &vga_arb_device_fops 1536}; 1537 1538static int __init vga_arb_device_init(void) 1539{ 1540 int rc; 1541 struct pci_dev *pdev; 1542 1543 rc = misc_register(&vga_arb_device); 1544 if (rc < 0) 1545 pr_err("error %d registering device\n", rc); 1546 1547 bus_register_notifier(&pci_bus_type, &pci_notifier); 1548 1549 /* Add all VGA class PCI devices by default */ 1550 pdev = NULL; 1551 while ((pdev = 1552 pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, 1553 PCI_ANY_ID, pdev)) != NULL) 1554 vga_arbiter_add_pci_device(pdev); 1555 1556 pr_info("loaded\n"); 1557 return rc; 1558} 1559subsys_initcall_sync(vga_arb_device_init); 1560