| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Benjamin Herrenschmidt | 4071 | 76.39% | 1 | 1.27% |
| Huacai Chen | 219 | 4.11% | 6 | 7.59% |
| Björn Helgaas | 212 | 3.98% | 9 | 11.39% |
| Dave Airlie | 205 | 3.85% | 3 | 3.80% |
| Gerd Hoffmann | 141 | 2.65% | 1 | 1.27% |
| Alex Williamson | 84 | 1.58% | 3 | 3.80% |
| Kai-Heng Feng | 43 | 0.81% | 1 | 1.27% |
| Aaron Ma | 41 | 0.77% | 2 | 2.53% |
| Linus Torvalds (pre-git) | 41 | 0.77% | 10 | 12.66% |
| Brian King | 25 | 0.47% | 1 | 1.27% |
| Julia Lawall | 24 | 0.45% | 1 | 1.27% |
| Thierry Reding | 23 | 0.43% | 3 | 3.80% |
| Mika Westerberg | 22 | 0.41% | 1 | 1.27% |
| Mike Travis | 21 | 0.39% | 2 | 2.53% |
| Yinghai Lu | 18 | 0.34% | 1 | 1.27% |
| Christoph Hellwig | 17 | 0.32% | 3 | 3.80% |
| Tiago Vignatti | 14 | 0.26% | 1 | 1.27% |
| Bruno Prémont | 12 | 0.23% | 1 | 1.27% |
| Matthew Garrett | 12 | 0.23% | 2 | 2.53% |
| Al Viro | 11 | 0.21% | 2 | 2.53% |
| Dmitriy Vyukov | 9 | 0.17% | 1 | 1.27% |
| Kirill A. Shutemov | 8 | 0.15% | 1 | 1.27% |
| Chris Wilson | 7 | 0.13% | 2 | 2.53% |
| Daniel Vetter | 7 | 0.13% | 2 | 2.53% |
| Yuji Shimada | 5 | 0.09% | 1 | 1.27% |
| Arnd Bergmann | 5 | 0.09% | 1 | 1.27% |
| Roland Dreier | 4 | 0.08% | 1 | 1.27% |
| Jiang Liu | 4 | 0.08% | 1 | 1.27% |
| Huang Ying | 3 | 0.06% | 1 | 1.27% |
| Rakib Mullick | 3 | 0.06% | 1 | 1.27% |
| Linus Torvalds | 2 | 0.04% | 2 | 2.53% |
| Tejun Heo | 2 | 0.04% | 1 | 1.27% |
| Lucas De Marchi | 2 | 0.04% | 1 | 1.27% |
| Ingo Molnar | 2 | 0.04% | 2 | 2.53% |
| Tim Schmielau | 2 | 0.04% | 1 | 1.27% |
| Andrew Morton | 2 | 0.04% | 1 | 1.27% |
| Alexander Chiang | 2 | 0.04% | 1 | 1.27% |
| Patrick Mochel | 1 | 0.02% | 1 | 1.27% |
| Kyle McMartin | 1 | 0.02% | 1 | 1.27% |
| Daniel J Blueman | 1 | 0.02% | 1 | 1.27% |
| Rasmus Villemoes | 1 | 0.02% | 1 | 1.27% |
| Total | 5329 | 79 |
// SPDX-License-Identifier: MIT /* * vgaarb.c: Implements the VGA arbitration. For details refer to * Documentation/gpu/vgaarbiter.rst * * (C) Copyright 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org> * (C) Copyright 2007 Paulo R. Zanoni <przanoni@gmail.com> * (C) Copyright 2007, 2009 Tiago Vignatti <vignatti@freedesktop.org> */ #define pr_fmt(fmt) "vgaarb: " fmt #define vgaarb_dbg(dev, fmt, arg...) dev_dbg(dev, "vgaarb: " fmt, ##arg) #define vgaarb_info(dev, fmt, arg...) dev_info(dev, "vgaarb: " fmt, ##arg) #define vgaarb_err(dev, fmt, arg...) dev_err(dev, "vgaarb: " fmt, ##arg) #include <linux/module.h> #include <linux/kernel.h> #include <linux/pci.h> #include <linux/errno.h> #include <linux/init.h> #include <linux/list.h> #include <linux/sched/signal.h> #include <linux/wait.h> #include <linux/spinlock.h> #include <linux/poll.h> #include <linux/miscdevice.h> #include <linux/slab.h> #include <linux/screen_info.h> #include <linux/vt.h> #include <linux/console.h> #include <linux/acpi.h> #include <linux/uaccess.h> #include <linux/vgaarb.h> static void vga_arbiter_notify_clients(void); /* * We keep a list of all vga devices in the system to speed * up the various operations of the arbiter */ struct vga_device { struct list_head list; struct pci_dev *pdev; unsigned int decodes; /* what does it decodes */ unsigned int owns; /* what does it owns */ unsigned int locks; /* what does it locks */ unsigned int io_lock_cnt; /* legacy IO lock count */ unsigned int mem_lock_cnt; /* legacy MEM lock count */ unsigned int io_norm_cnt; /* normal IO count */ unsigned int mem_norm_cnt; /* normal MEM count */ bool bridge_has_one_vga; bool is_firmware_default; /* device selected by firmware */ unsigned int (*set_decode)(struct pci_dev *pdev, bool decode); }; static LIST_HEAD(vga_list); static int vga_count, vga_decode_count; static bool vga_arbiter_used; static DEFINE_SPINLOCK(vga_lock); static DECLARE_WAIT_QUEUE_HEAD(vga_wait_queue); static const char *vga_iostate_to_str(unsigned int iostate) { /* Ignore VGA_RSRC_IO and VGA_RSRC_MEM */ iostate &= VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; switch (iostate) { case VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM: return "io+mem"; case VGA_RSRC_LEGACY_IO: return "io"; case VGA_RSRC_LEGACY_MEM: return "mem"; } return "none"; } static int vga_str_to_iostate(char *buf, int str_size, int *io_state) { /* we could in theory hand out locks on IO and mem * separately to userspace but it can cause deadlocks */ if (strncmp(buf, "none", 4) == 0) { *io_state = VGA_RSRC_NONE; return 1; } /* XXX We're not chekcing the str_size! */ if (strncmp(buf, "io+mem", 6) == 0) goto both; else if (strncmp(buf, "io", 2) == 0) goto both; else if (strncmp(buf, "mem", 3) == 0) goto both; return 0; both: *io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; return 1; } /* this is only used a cookie - it should not be dereferenced */ static struct pci_dev *vga_default; /* Find somebody in our list */ static struct vga_device *vgadev_find(struct pci_dev *pdev) { struct vga_device *vgadev; list_for_each_entry(vgadev, &vga_list, list) if (pdev == vgadev->pdev) return vgadev; return NULL; } /** * vga_default_device - return the default VGA device, for vgacon * * This can be defined by the platform. The default implementation * is rather dumb and will probably only work properly on single * vga card setups and/or x86 platforms. * * If your VGA default device is not PCI, you'll have to return * NULL here. In this case, I assume it will not conflict with * any PCI card. If this is not true, I'll have to define two archs * hooks for enabling/disabling the VGA default device if that is * possible. This may be a problem with real _ISA_ VGA cards, in * addition to a PCI one. I don't know at this point how to deal * with that card. Can theirs IOs be disabled at all ? If not, then * I suppose it's a matter of having the proper arch hook telling * us about it, so we basically never allow anybody to succeed a * vga_get()... */ struct pci_dev *vga_default_device(void) { return vga_default; } EXPORT_SYMBOL_GPL(vga_default_device); void vga_set_default_device(struct pci_dev *pdev) { if (vga_default == pdev) return; pci_dev_put(vga_default); vga_default = pci_dev_get(pdev); } /** * vga_remove_vgacon - deactivete vga console * * Unbind and unregister vgacon in case pdev is the default vga * device. Can be called by gpu drivers on initialization to make * sure vga register access done by vgacon will not disturb the * device. * * @pdev: pci device. */ #if !defined(CONFIG_VGA_CONSOLE) int vga_remove_vgacon(struct pci_dev *pdev) { return 0; } #elif !defined(CONFIG_DUMMY_CONSOLE) int vga_remove_vgacon(struct pci_dev *pdev) { return -ENODEV; } #else int vga_remove_vgacon(struct pci_dev *pdev) { int ret = 0; if (pdev != vga_default) return 0; vgaarb_info(&pdev->dev, "deactivate vga console\n"); console_lock(); if (con_is_bound(&vga_con)) ret = do_take_over_console(&dummy_con, 0, MAX_NR_CONSOLES - 1, 1); if (ret == 0) { ret = do_unregister_con_driver(&vga_con); /* Ignore "already unregistered". */ if (ret == -ENODEV) ret = 0; } console_unlock(); return ret; } #endif EXPORT_SYMBOL(vga_remove_vgacon); /* If we don't ever use VGA arb we should avoid turning off anything anywhere due to old X servers getting confused about the boot device not being VGA */ static void vga_check_first_use(void) { /* we should inform all GPUs in the system that * VGA arb has occurred and to try and disable resources * if they can */ if (!vga_arbiter_used) { vga_arbiter_used = true; vga_arbiter_notify_clients(); } } static struct vga_device *__vga_tryget(struct vga_device *vgadev, unsigned int rsrc) { struct device *dev = &vgadev->pdev->dev; unsigned int wants, legacy_wants, match; struct vga_device *conflict; unsigned int pci_bits; u32 flags = 0; /* Account for "normal" resources to lock. If we decode the legacy, * counterpart, we need to request it as well */ if ((rsrc & VGA_RSRC_NORMAL_IO) && (vgadev->decodes & VGA_RSRC_LEGACY_IO)) rsrc |= VGA_RSRC_LEGACY_IO; if ((rsrc & VGA_RSRC_NORMAL_MEM) && (vgadev->decodes & VGA_RSRC_LEGACY_MEM)) rsrc |= VGA_RSRC_LEGACY_MEM; vgaarb_dbg(dev, "%s: %d\n", __func__, rsrc); vgaarb_dbg(dev, "%s: owns: %d\n", __func__, vgadev->owns); /* Check what resources we need to acquire */ wants = rsrc & ~vgadev->owns; /* We already own everything, just mark locked & bye bye */ if (wants == 0) goto lock_them; /* We don't need to request a legacy resource, we just enable * appropriate decoding and go */ legacy_wants = wants & VGA_RSRC_LEGACY_MASK; if (legacy_wants == 0) goto enable_them; /* Ok, we don't, let's find out how we need to kick off */ list_for_each_entry(conflict, &vga_list, list) { unsigned int lwants = legacy_wants; unsigned int change_bridge = 0; /* Don't conflict with myself */ if (vgadev == conflict) continue; /* We have a possible conflict. before we go further, we must * check if we sit on the same bus as the conflicting device. * if we don't, then we must tie both IO and MEM resources * together since there is only a single bit controlling * VGA forwarding on P2P bridges */ if (vgadev->pdev->bus != conflict->pdev->bus) { change_bridge = 1; lwants = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; } /* Check if the guy has a lock on the resource. If he does, * return the conflicting entry */ if (conflict->locks & lwants) return conflict; /* Ok, now check if it owns the resource we want. We can * lock resources that are not decoded, therefore a device * can own resources it doesn't decode. */ match = lwants & conflict->owns; if (!match) continue; /* looks like he doesn't have a lock, we can steal * them from him */ flags = 0; pci_bits = 0; /* If we can't control legacy resources via the bridge, we * also need to disable normal decoding. */ if (!conflict->bridge_has_one_vga) { if ((match & conflict->decodes) & VGA_RSRC_LEGACY_MEM) pci_bits |= PCI_COMMAND_MEMORY; if ((match & conflict->decodes) & VGA_RSRC_LEGACY_IO) pci_bits |= PCI_COMMAND_IO; if (pci_bits) flags |= PCI_VGA_STATE_CHANGE_DECODES; } if (change_bridge) flags |= PCI_VGA_STATE_CHANGE_BRIDGE; pci_set_vga_state(conflict->pdev, false, pci_bits, flags); conflict->owns &= ~match; /* If we disabled normal decoding, reflect it in owns */ if (pci_bits & PCI_COMMAND_MEMORY) conflict->owns &= ~VGA_RSRC_NORMAL_MEM; if (pci_bits & PCI_COMMAND_IO) conflict->owns &= ~VGA_RSRC_NORMAL_IO; } enable_them: /* ok dude, we got it, everybody conflicting has been disabled, let's * enable us. Mark any bits in "owns" regardless of whether we * decoded them. We can lock resources we don't decode, therefore * we must track them via "owns". */ flags = 0; pci_bits = 0; if (!vgadev->bridge_has_one_vga) { flags |= PCI_VGA_STATE_CHANGE_DECODES; if (wants & (VGA_RSRC_LEGACY_MEM|VGA_RSRC_NORMAL_MEM)) pci_bits |= PCI_COMMAND_MEMORY; if (wants & (VGA_RSRC_LEGACY_IO|VGA_RSRC_NORMAL_IO)) pci_bits |= PCI_COMMAND_IO; } if (wants & VGA_RSRC_LEGACY_MASK) flags |= PCI_VGA_STATE_CHANGE_BRIDGE; pci_set_vga_state(vgadev->pdev, true, pci_bits, flags); vgadev->owns |= wants; lock_them: vgadev->locks |= (rsrc & VGA_RSRC_LEGACY_MASK); if (rsrc & VGA_RSRC_LEGACY_IO) vgadev->io_lock_cnt++; if (rsrc & VGA_RSRC_LEGACY_MEM) vgadev->mem_lock_cnt++; if (rsrc & VGA_RSRC_NORMAL_IO) vgadev->io_norm_cnt++; if (rsrc & VGA_RSRC_NORMAL_MEM) vgadev->mem_norm_cnt++; return NULL; } static void __vga_put(struct vga_device *vgadev, unsigned int rsrc) { struct device *dev = &vgadev->pdev->dev; unsigned int old_locks = vgadev->locks; vgaarb_dbg(dev, "%s\n", __func__); /* Update our counters, and account for equivalent legacy resources * if we decode them */ if ((rsrc & VGA_RSRC_NORMAL_IO) && vgadev->io_norm_cnt > 0) { vgadev->io_norm_cnt--; if (vgadev->decodes & VGA_RSRC_LEGACY_IO) rsrc |= VGA_RSRC_LEGACY_IO; } if ((rsrc & VGA_RSRC_NORMAL_MEM) && vgadev->mem_norm_cnt > 0) { vgadev->mem_norm_cnt--; if (vgadev->decodes & VGA_RSRC_LEGACY_MEM) rsrc |= VGA_RSRC_LEGACY_MEM; } if ((rsrc & VGA_RSRC_LEGACY_IO) && vgadev->io_lock_cnt > 0) vgadev->io_lock_cnt--; if ((rsrc & VGA_RSRC_LEGACY_MEM) && vgadev->mem_lock_cnt > 0) vgadev->mem_lock_cnt--; /* Just clear lock bits, we do lazy operations so we don't really * have to bother about anything else at this point */ if (vgadev->io_lock_cnt == 0) vgadev->locks &= ~VGA_RSRC_LEGACY_IO; if (vgadev->mem_lock_cnt == 0) vgadev->locks &= ~VGA_RSRC_LEGACY_MEM; /* Kick the wait queue in case somebody was waiting if we actually * released something */ if (old_locks != vgadev->locks) wake_up_all(&vga_wait_queue); } /** * vga_get - acquire & locks VGA resources * @pdev: pci device of the VGA card or NULL for the system default * @rsrc: bit mask of resources to acquire and lock * @interruptible: blocking should be interruptible by signals ? * * This function acquires VGA resources for the given card and mark those * resources locked. If the resource requested are "normal" (and not legacy) * resources, the arbiter will first check whether the card is doing legacy * decoding for that type of resource. If yes, the lock is "converted" into a * legacy resource lock. * * The arbiter will first look for all VGA cards that might conflict and disable * their IOs and/or Memory access, including VGA forwarding on P2P bridges if * necessary, so that the requested resources can be used. Then, the card is * marked as locking these resources and the IO and/or Memory accesses are * enabled on the card (including VGA forwarding on parent P2P bridges if any). * * This function will block if some conflicting card is already locking one of * the required resources (or any resource on a different bus segment, since P2P * bridges don't differentiate VGA memory and IO afaik). You can indicate * whether this blocking should be interruptible by a signal (for userland * interface) or not. * * Must not be called at interrupt time or in atomic context. If the card * already owns the resources, the function succeeds. Nested calls are * supported (a per-resource counter is maintained) * * On success, release the VGA resource again with vga_put(). * * Returns: * * 0 on success, negative error code on failure. */ int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible) { struct vga_device *vgadev, *conflict; unsigned long flags; wait_queue_entry_t wait; int rc = 0; vga_check_first_use(); /* The one who calls us should check for this, but lets be sure... */ if (pdev == NULL) pdev = vga_default_device(); if (pdev == NULL) return 0; for (;;) { spin_lock_irqsave(&vga_lock, flags); vgadev = vgadev_find(pdev); if (vgadev == NULL) { spin_unlock_irqrestore(&vga_lock, flags); rc = -ENODEV; break; } conflict = __vga_tryget(vgadev, rsrc); spin_unlock_irqrestore(&vga_lock, flags); if (conflict == NULL) break; /* We have a conflict, we wait until somebody kicks the * work queue. Currently we have one work queue that we * kick each time some resources are released, but it would * be fairly easy to have a per device one so that we only * need to attach to the conflicting device */ init_waitqueue_entry(&wait, current); add_wait_queue(&vga_wait_queue, &wait); set_current_state(interruptible ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE); if (interruptible && signal_pending(current)) { __set_current_state(TASK_RUNNING); remove_wait_queue(&vga_wait_queue, &wait); rc = -ERESTARTSYS; break; } schedule(); remove_wait_queue(&vga_wait_queue, &wait); } return rc; } EXPORT_SYMBOL(vga_get); /** * vga_tryget - try to acquire & lock legacy VGA resources * @pdev: pci devivce of VGA card or NULL for system default * @rsrc: bit mask of resources to acquire and lock * * This function performs the same operation as vga_get(), but will return an * error (-EBUSY) instead of blocking if the resources are already locked by * another card. It can be called in any context * * On success, release the VGA resource again with vga_put(). * * Returns: * * 0 on success, negative error code on failure. */ static int vga_tryget(struct pci_dev *pdev, unsigned int rsrc) { struct vga_device *vgadev; unsigned long flags; int rc = 0; vga_check_first_use(); /* The one who calls us should check for this, but lets be sure... */ if (pdev == NULL) pdev = vga_default_device(); if (pdev == NULL) return 0; spin_lock_irqsave(&vga_lock, flags); vgadev = vgadev_find(pdev); if (vgadev == NULL) { rc = -ENODEV; goto bail; } if (__vga_tryget(vgadev, rsrc)) rc = -EBUSY; bail: spin_unlock_irqrestore(&vga_lock, flags); return rc; } /** * vga_put - release lock on legacy VGA resources * @pdev: pci device of VGA card or NULL for system default * @rsrc: but mask of resource to release * * This fuction releases resources previously locked by vga_get() or * vga_tryget(). The resources aren't disabled right away, so that a subsequence * vga_get() on the same card will succeed immediately. Resources have a * counter, so locks are only released if the counter reaches 0. */ void vga_put(struct pci_dev *pdev, unsigned int rsrc) { struct vga_device *vgadev; unsigned long flags; /* The one who calls us should check for this, but lets be sure... */ if (pdev == NULL) pdev = vga_default_device(); if (pdev == NULL) return; spin_lock_irqsave(&vga_lock, flags); vgadev = vgadev_find(pdev); if (vgadev == NULL) goto bail; __vga_put(vgadev, rsrc); bail: spin_unlock_irqrestore(&vga_lock, flags); } EXPORT_SYMBOL(vga_put); static bool vga_is_firmware_default(struct pci_dev *pdev) { #if defined(CONFIG_X86) || defined(CONFIG_IA64) u64 base = screen_info.lfb_base; u64 size = screen_info.lfb_size; struct resource *r; u64 limit; /* Select the device owning the boot framebuffer if there is one */ if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) base |= (u64)screen_info.ext_lfb_base << 32; limit = base + size; /* Does firmware framebuffer belong to us? */ pci_dev_for_each_resource(pdev, r) { if (resource_type(r) != IORESOURCE_MEM) continue; if (!r->start || !r->end) continue; if (base < r->start || limit >= r->end) continue; return true; } #endif return false; } static bool vga_arb_integrated_gpu(struct device *dev) { #if defined(CONFIG_ACPI) struct acpi_device *adev = ACPI_COMPANION(dev); return adev && !strcmp(acpi_device_hid(adev), ACPI_VIDEO_HID); #else return false; #endif } /* * Return true if vgadev is a better default VGA device than the best one * we've seen so far. */ static bool vga_is_boot_device(struct vga_device *vgadev) { struct vga_device *boot_vga = vgadev_find(vga_default_device()); struct pci_dev *pdev = vgadev->pdev; u16 cmd, boot_cmd; /* * We select the default VGA device in this order: * Firmware framebuffer (see vga_arb_select_default_device()) * Legacy VGA device (owns VGA_RSRC_LEGACY_MASK) * Non-legacy integrated device (see vga_arb_select_default_device()) * Non-legacy discrete device (see vga_arb_select_default_device()) * Other device (see vga_arb_select_default_device()) */ /* * We always prefer a firmware default device, so if we've already * found one, there's no need to consider vgadev. */ if (boot_vga && boot_vga->is_firmware_default) return false; if (vga_is_firmware_default(pdev)) { vgadev->is_firmware_default = true; return true; } /* * A legacy VGA device has MEM and IO enabled and any bridges * leading to it have PCI_BRIDGE_CTL_VGA enabled so the legacy * resources ([mem 0xa0000-0xbffff], [io 0x3b0-0x3bb], etc) are * routed to it. * * We use the first one we find, so if we've already found one, * vgadev is no better. */ if (boot_vga && (boot_vga->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK) return false; if ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK) return true; /* * If we haven't found a legacy VGA device, accept a non-legacy * device. It may have either IO or MEM enabled, and bridges may * not have PCI_BRIDGE_CTL_VGA enabled, so it may not be able to * use legacy VGA resources. Prefer an integrated GPU over others. */ pci_read_config_word(pdev, PCI_COMMAND, &cmd); if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) { /* * An integrated GPU overrides a previous non-legacy * device. We expect only a single integrated GPU, but if * there are more, we use the *last* because that was the * previous behavior. */ if (vga_arb_integrated_gpu(&pdev->dev)) return true; /* * We prefer the first non-legacy discrete device we find. * If we already found one, vgadev is no better. */ if (boot_vga) { pci_read_config_word(boot_vga->pdev, PCI_COMMAND, &boot_cmd); if (boot_cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) return false; } return true; } /* * vgadev has neither IO nor MEM enabled. If we haven't found any * other VGA devices, it is the best candidate so far. */ if (!boot_vga) return true; return false; } /* * Rules for using a bridge to control a VGA descendant decoding: if a bridge * has only one VGA descendant then it can be used to control the VGA routing * for that device. It should always use the bridge closest to the device to * control it. If a bridge has a direct VGA descendant, but also have a sub- * bridge VGA descendant then we cannot use that bridge to control the direct * VGA descendant. So for every device we register, we need to iterate all * its parent bridges so we can invalidate any devices using them properly. */ static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev) { struct vga_device *same_bridge_vgadev; struct pci_bus *new_bus, *bus; struct pci_dev *new_bridge, *bridge; vgadev->bridge_has_one_vga = true; if (list_empty(&vga_list)) { vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n"); return; } /* okay iterate the new devices bridge hierarachy */ new_bus = vgadev->pdev->bus; while (new_bus) { new_bridge = new_bus->self; /* go through list of devices already registered */ list_for_each_entry(same_bridge_vgadev, &vga_list, list) { bus = same_bridge_vgadev->pdev->bus; bridge = bus->self; /* see if the share a bridge with this device */ if (new_bridge == bridge) { /* * If their direct parent bridge is the same * as any bridge of this device then it can't * be used for that device. */ same_bridge_vgadev->bridge_has_one_vga = false; } /* * Now iterate the previous devices bridge hierarchy. * If the new devices parent bridge is in the other * devices hierarchy then we can't use it to control * this device */ while (bus) { bridge = bus->self; if (bridge && bridge == vgadev->pdev->bus->self) vgadev->bridge_has_one_vga = false; bus = bus->parent; } } new_bus = new_bus->parent; } if (vgadev->bridge_has_one_vga) vgaarb_info(&vgadev->pdev->dev, "bridge control possible\n"); else vgaarb_info(&vgadev->pdev->dev, "no bridge control possible\n"); } /* * Currently, we assume that the "initial" setup of the system is * not sane, that is we come up with conflicting devices and let * the arbiter's client decides if devices decodes or not legacy * things. */ static bool vga_arbiter_add_pci_device(struct pci_dev *pdev) { struct vga_device *vgadev; unsigned long flags; struct pci_bus *bus; struct pci_dev *bridge; u16 cmd; /* Only deal with VGA class devices */ if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA) return false; /* Allocate structure */ vgadev = kzalloc(sizeof(struct vga_device), GFP_KERNEL); if (vgadev == NULL) { vgaarb_err(&pdev->dev, "failed to allocate VGA arbiter data\n"); /* * What to do on allocation failure ? For now, let's just do * nothing, I'm not sure there is anything saner to be done. */ return false; } /* Take lock & check for duplicates */ spin_lock_irqsave(&vga_lock, flags); if (vgadev_find(pdev) != NULL) { BUG_ON(1); goto fail; } vgadev->pdev = pdev; /* By default, assume we decode everything */ vgadev->decodes = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM | VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM; /* by default mark it as decoding */ vga_decode_count++; /* Mark that we "own" resources based on our enables, we will * clear that below if the bridge isn't forwarding */ pci_read_config_word(pdev, PCI_COMMAND, &cmd); if (cmd & PCI_COMMAND_IO) vgadev->owns |= VGA_RSRC_LEGACY_IO; if (cmd & PCI_COMMAND_MEMORY) vgadev->owns |= VGA_RSRC_LEGACY_MEM; /* Check if VGA cycles can get down to us */ bus = pdev->bus; while (bus) { bridge = bus->self; if (bridge) { u16 l; pci_read_config_word(bridge, PCI_BRIDGE_CONTROL, &l); if (!(l & PCI_BRIDGE_CTL_VGA)) { vgadev->owns = 0; break; } } bus = bus->parent; } if (vga_is_boot_device(vgadev)) { vgaarb_info(&pdev->dev, "setting as boot VGA device%s\n", vga_default_device() ? " (overriding previous)" : ""); vga_set_default_device(pdev); } vga_arbiter_check_bridge_sharing(vgadev); /* Add to the list */ list_add_tail(&vgadev->list, &vga_list); vga_count++; vgaarb_info(&pdev->dev, "VGA device added: decodes=%s,owns=%s,locks=%s\n", vga_iostate_to_str(vgadev->decodes), vga_iostate_to_str(vgadev->owns), vga_iostate_to_str(vgadev->locks)); spin_unlock_irqrestore(&vga_lock, flags); return true; fail: spin_unlock_irqrestore(&vga_lock, flags); kfree(vgadev); return false; } static bool vga_arbiter_del_pci_device(struct pci_dev *pdev) { struct vga_device *vgadev; unsigned long flags; bool ret = true; spin_lock_irqsave(&vga_lock, flags); vgadev = vgadev_find(pdev); if (vgadev == NULL) { ret = false; goto bail; } if (vga_default == pdev) vga_set_default_device(NULL); if (vgadev->decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM)) vga_decode_count--; /* Remove entry from list */ list_del(&vgadev->list); vga_count--; /* Wake up all possible waiters */ wake_up_all(&vga_wait_queue); bail: spin_unlock_irqrestore(&vga_lock, flags); kfree(vgadev); return ret; } /* this is called with the lock */ static inline void vga_update_device_decodes(struct vga_device *vgadev, int new_decodes) { struct device *dev = &vgadev->pdev->dev; int old_decodes, decodes_removed, decodes_unlocked; old_decodes = vgadev->decodes; decodes_removed = ~new_decodes & old_decodes; decodes_unlocked = vgadev->locks & decodes_removed; vgadev->decodes = new_decodes; vgaarb_info(dev, "changed VGA decodes: olddecodes=%s,decodes=%s:owns=%s\n", vga_iostate_to_str(old_decodes), vga_iostate_to_str(vgadev->decodes), vga_iostate_to_str(vgadev->owns)); /* if we removed locked decodes, lock count goes to zero, and release */ if (decodes_unlocked) { if (decodes_unlocked & VGA_RSRC_LEGACY_IO) vgadev->io_lock_cnt = 0; if (decodes_unlocked & VGA_RSRC_LEGACY_MEM) vgadev->mem_lock_cnt = 0; __vga_put(vgadev, decodes_unlocked); } /* change decodes counter */ if (old_decodes & VGA_RSRC_LEGACY_MASK && !(new_decodes & VGA_RSRC_LEGACY_MASK)) vga_decode_count--; if (!(old_decodes & VGA_RSRC_LEGACY_MASK) && new_decodes & VGA_RSRC_LEGACY_MASK) vga_decode_count++; vgaarb_dbg(dev, "decoding count now is: %d\n", vga_decode_count); } static void __vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes, bool userspace) { struct vga_device *vgadev; unsigned long flags; decodes &= VGA_RSRC_LEGACY_MASK; spin_lock_irqsave(&vga_lock, flags); vgadev = vgadev_find(pdev); if (vgadev == NULL) goto bail; /* don't let userspace futz with kernel driver decodes */ if (userspace && vgadev->set_decode) goto bail; /* update the device decodes + counter */ vga_update_device_decodes(vgadev, decodes); /* XXX if somebody is going from "doesn't decode" to "decodes" state * here, additional care must be taken as we may have pending owner * ship of non-legacy region ... */ bail: spin_unlock_irqrestore(&vga_lock, flags); } /** * vga_set_legacy_decoding * @pdev: pci device of the VGA card * @decodes: bit mask of what legacy regions the card decodes * * Indicates to the arbiter if the card decodes legacy VGA IOs, legacy VGA * Memory, both, or none. All cards default to both, the card driver (fbdev for * example) should tell the arbiter if it has disabled legacy decoding, so the * card can be left out of the arbitration process (and can be safe to take * interrupts at any time. */ void vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes) { __vga_set_legacy_decoding(pdev, decodes, false); } EXPORT_SYMBOL(vga_set_legacy_decoding); /** * vga_client_register - register or unregister a VGA arbitration client * @pdev: pci device of the VGA client * @set_decode: vga decode change callback * * Clients have two callback mechanisms they can use. * * @set_decode callback: If a client can disable its GPU VGA resource, it * will get a callback from this to set the encode/decode state. * * Rationale: we cannot disable VGA decode resources unconditionally some single * GPU laptops seem to require ACPI or BIOS access to the VGA registers to * control things like backlights etc. Hopefully newer multi-GPU laptops do * something saner, and desktops won't have any special ACPI for this. The * driver will get a callback when VGA arbitration is first used by userspace * since some older X servers have issues. * * This function does not check whether a client for @pdev has been registered * already. * * To unregister just call vga_client_unregister(). * * Returns: 0 on success, -1 on failure */ int vga_client_register(struct pci_dev *pdev, unsigned int (*set_decode)(struct pci_dev *pdev, bool decode)) { int ret = -ENODEV; struct vga_device *vgadev; unsigned long flags; spin_lock_irqsave(&vga_lock, flags); vgadev = vgadev_find(pdev); if (!vgadev) goto bail; vgadev->set_decode = set_decode; ret = 0; bail: spin_unlock_irqrestore(&vga_lock, flags); return ret; } EXPORT_SYMBOL(vga_client_register); /* * Char driver implementation * * Semantics is: * * open : open user instance of the arbitrer. by default, it's * attached to the default VGA device of the system. * * close : close user instance, release locks * * read : return a string indicating the status of the target. * an IO state string is of the form {io,mem,io+mem,none}, * mc and ic are respectively mem and io lock counts (for * debugging/diagnostic only). "decodes" indicate what the * card currently decodes, "owns" indicates what is currently * enabled on it, and "locks" indicates what is locked by this * card. If the card is unplugged, we get "invalid" then for * card_ID and an -ENODEV error is returned for any command * until a new card is targeted * * "<card_ID>,decodes=<io_state>,owns=<io_state>,locks=<io_state> (ic,mc)" * * write : write a command to the arbiter. List of commands is: * * target <card_ID> : switch target to card <card_ID> (see below) * lock <io_state> : acquires locks on target ("none" is invalid io_state) * trylock <io_state> : non-blocking acquire locks on target * unlock <io_state> : release locks on target * unlock all : release all locks on target held by this user * decodes <io_state> : set the legacy decoding attributes for the card * * poll : event if something change on any card (not just the target) * * card_ID is of the form "PCI:domain:bus:dev.fn". It can be set to "default" * to go back to the system default card (TODO: not implemented yet). * Currently, only PCI is supported as a prefix, but the userland API may * support other bus types in the future, even if the current kernel * implementation doesn't. * * Note about locks: * * The driver keeps track of which user has what locks on which card. It * supports stacking, like the kernel one. This complexifies the implementation * a bit, but makes the arbiter more tolerant to userspace problems and able * to properly cleanup in all cases when a process dies. * Currently, a max of 16 cards simultaneously can have locks issued from * userspace for a given user (file descriptor instance) of the arbiter. * * If the device is hot-unplugged, there is a hook inside the module to notify * they being added/removed in the system and automatically added/removed in * the arbiter. */ #define MAX_USER_CARDS CONFIG_VGA_ARB_MAX_GPUS #define PCI_INVALID_CARD ((struct pci_dev *)-1UL) /* * Each user has an array of these, tracking which cards have locks */ struct vga_arb_user_card { struct pci_dev *pdev; unsigned int mem_cnt; unsigned int io_cnt; }; struct vga_arb_private { struct list_head list; struct pci_dev *target; struct vga_arb_user_card cards[MAX_USER_CARDS]; spinlock_t lock; }; static LIST_HEAD(vga_user_list); static DEFINE_SPINLOCK(vga_user_lock); /* * This function gets a string in the format: "PCI:domain:bus:dev.fn" and * returns the respective values. If the string is not in this format, * it returns 0. */ static int vga_pci_str_to_vars(char *buf, int count, unsigned int *domain, unsigned int *bus, unsigned int *devfn) { int n; unsigned int slot, func; n = sscanf(buf, "PCI:%x:%x:%x.%x", domain, bus, &slot, &func); if (n != 4) return 0; *devfn = PCI_DEVFN(slot, func); return 1; } static ssize_t vga_arb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { struct vga_arb_private *priv = file->private_data; struct vga_device *vgadev; struct pci_dev *pdev; unsigned long flags; size_t len; int rc; char *lbuf; lbuf = kmalloc(1024, GFP_KERNEL); if (lbuf == NULL) return -ENOMEM; /* Protects vga_list */ spin_lock_irqsave(&vga_lock, flags); /* If we are targeting the default, use it */ pdev = priv->target; if (pdev == NULL || pdev == PCI_INVALID_CARD) { spin_unlock_irqrestore(&vga_lock, flags); len = sprintf(lbuf, "invalid"); goto done; } /* Find card vgadev structure */ vgadev = vgadev_find(pdev); if (vgadev == NULL) { /* Wow, it's not in the list, that shouldn't happen, * let's fix us up and return invalid card */ spin_unlock_irqrestore(&vga_lock, flags); len = sprintf(lbuf, "invalid"); goto done; } /* Fill the buffer with infos */ len = snprintf(lbuf, 1024, "count:%d,PCI:%s,decodes=%s,owns=%s,locks=%s(%u:%u)\n", vga_decode_count, pci_name(pdev), vga_iostate_to_str(vgadev->decodes), vga_iostate_to_str(vgadev->owns), vga_iostate_to_str(vgadev->locks), vgadev->io_lock_cnt, vgadev->mem_lock_cnt); spin_unlock_irqrestore(&vga_lock, flags); done: /* Copy that to user */ if (len > count) len = count; rc = copy_to_user(buf, lbuf, len); kfree(lbuf); if (rc) return -EFAULT; return len; } /* * TODO: To avoid parsing inside kernel and to improve the speed we may * consider use ioctl here */ static ssize_t vga_arb_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { struct vga_arb_private *priv = file->private_data; struct vga_arb_user_card *uc = NULL; struct pci_dev *pdev; unsigned int io_state; char kbuf[64], *curr_pos; size_t remaining = count; int ret_val; int i; if (count >= sizeof(kbuf)) return -EINVAL; if (copy_from_user(kbuf, buf, count)) return -EFAULT; curr_pos = kbuf; kbuf[count] = '\0'; /* Just to make sure... */ if (strncmp(curr_pos, "lock ", 5) == 0) { curr_pos += 5; remaining -= 5; pr_debug("client 0x%p called 'lock'\n", priv); if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { ret_val = -EPROTO; goto done; } if (io_state == VGA_RSRC_NONE) { ret_val = -EPROTO; goto done; } pdev = priv->target; if (priv->target == NULL) { ret_val = -ENODEV; goto done; } vga_get_uninterruptible(pdev, io_state); /* Update the client's locks lists... */ for (i = 0; i < MAX_USER_CARDS; i++) { if (priv->cards[i].pdev == pdev) { if (io_state & VGA_RSRC_LEGACY_IO) priv->cards[i].io_cnt++; if (io_state & VGA_RSRC_LEGACY_MEM) priv->cards[i].mem_cnt++; break; } } ret_val = count; goto done; } else if (strncmp(curr_pos, "unlock ", 7) == 0) { curr_pos += 7; remaining -= 7; pr_debug("client 0x%p called 'unlock'\n", priv); if (strncmp(curr_pos, "all", 3) == 0) io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; else { if (!vga_str_to_iostate (curr_pos, remaining, &io_state)) { ret_val = -EPROTO; goto done; } /* TODO: Add this? if (io_state == VGA_RSRC_NONE) { ret_val = -EPROTO; goto done; } */ } pdev = priv->target; if (priv->target == NULL) { ret_val = -ENODEV; goto done; } for (i = 0; i < MAX_USER_CARDS; i++) { if (priv->cards[i].pdev == pdev) uc = &priv->cards[i]; } if (!uc) { ret_val = -EINVAL; goto done; } if (io_state & VGA_RSRC_LEGACY_IO && uc->io_cnt == 0) { ret_val = -EINVAL; goto done; } if (io_state & VGA_RSRC_LEGACY_MEM && uc->mem_cnt == 0) { ret_val = -EINVAL; goto done; } vga_put(pdev, io_state); if (io_state & VGA_RSRC_LEGACY_IO) uc->io_cnt--; if (io_state & VGA_RSRC_LEGACY_MEM) uc->mem_cnt--; ret_val = count; goto done; } else if (strncmp(curr_pos, "trylock ", 8) == 0) { curr_pos += 8; remaining -= 8; pr_debug("client 0x%p called 'trylock'\n", priv); if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { ret_val = -EPROTO; goto done; } /* TODO: Add this? if (io_state == VGA_RSRC_NONE) { ret_val = -EPROTO; goto done; } */ pdev = priv->target; if (priv->target == NULL) { ret_val = -ENODEV; goto done; } if (vga_tryget(pdev, io_state)) { /* Update the client's locks lists... */ for (i = 0; i < MAX_USER_CARDS; i++) { if (priv->cards[i].pdev == pdev) { if (io_state & VGA_RSRC_LEGACY_IO) priv->cards[i].io_cnt++; if (io_state & VGA_RSRC_LEGACY_MEM) priv->cards[i].mem_cnt++; break; } } ret_val = count; goto done; } else { ret_val = -EBUSY; goto done; } } else if (strncmp(curr_pos, "target ", 7) == 0) { unsigned int domain, bus, devfn; struct vga_device *vgadev; curr_pos += 7; remaining -= 7; pr_debug("client 0x%p called 'target'\n", priv); /* if target is default */ if (!strncmp(curr_pos, "default", 7)) pdev = pci_dev_get(vga_default_device()); else { if (!vga_pci_str_to_vars(curr_pos, remaining, &domain, &bus, &devfn)) { ret_val = -EPROTO; goto done; } pdev = pci_get_domain_bus_and_slot(domain, bus, devfn); if (!pdev) { pr_debug("invalid PCI address %04x:%02x:%02x.%x\n", domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn)); ret_val = -ENODEV; goto done; } pr_debug("%s ==> %04x:%02x:%02x.%x pdev %p\n", curr_pos, domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn), pdev); } vgadev = vgadev_find(pdev); pr_debug("vgadev %p\n", vgadev); if (vgadev == NULL) { if (pdev) { vgaarb_dbg(&pdev->dev, "not a VGA device\n"); pci_dev_put(pdev); } ret_val = -ENODEV; goto done; } priv->target = pdev; for (i = 0; i < MAX_USER_CARDS; i++) { if (priv->cards[i].pdev == pdev) break; if (priv->cards[i].pdev == NULL) { priv->cards[i].pdev = pdev; priv->cards[i].io_cnt = 0; priv->cards[i].mem_cnt = 0; break; } } if (i == MAX_USER_CARDS) { vgaarb_dbg(&pdev->dev, "maximum user cards (%d) number reached, ignoring this one!\n", MAX_USER_CARDS); pci_dev_put(pdev); /* XXX: which value to return? */ ret_val = -ENOMEM; goto done; } ret_val = count; pci_dev_put(pdev); goto done; } else if (strncmp(curr_pos, "decodes ", 8) == 0) { curr_pos += 8; remaining -= 8; pr_debug("client 0x%p called 'decodes'\n", priv); if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { ret_val = -EPROTO; goto done; } pdev = priv->target; if (priv->target == NULL) { ret_val = -ENODEV; goto done; } __vga_set_legacy_decoding(pdev, io_state, true); ret_val = count; goto done; } /* If we got here, the message written is not part of the protocol! */ return -EPROTO; done: return ret_val; } static __poll_t vga_arb_fpoll(struct file *file, poll_table *wait) { pr_debug("%s\n", __func__); poll_wait(file, &vga_wait_queue, wait); return EPOLLIN; } static int vga_arb_open(struct inode *inode, struct file *file) { struct vga_arb_private *priv; unsigned long flags; pr_debug("%s\n", __func__); priv = kzalloc(sizeof(*priv), GFP_KERNEL); if (priv == NULL) return -ENOMEM; spin_lock_init(&priv->lock); file->private_data = priv; spin_lock_irqsave(&vga_user_lock, flags); list_add(&priv->list, &vga_user_list); spin_unlock_irqrestore(&vga_user_lock, flags); /* Set the client' lists of locks */ priv->target = vga_default_device(); /* Maybe this is still null! */ priv->cards[0].pdev = priv->target; priv->cards[0].io_cnt = 0; priv->cards[0].mem_cnt = 0; return 0; } static int vga_arb_release(struct inode *inode, struct file *file) { struct vga_arb_private *priv = file->private_data; struct vga_arb_user_card *uc; unsigned long flags; int i; pr_debug("%s\n", __func__); spin_lock_irqsave(&vga_user_lock, flags); list_del(&priv->list); for (i = 0; i < MAX_USER_CARDS; i++) { uc = &priv->cards[i]; if (uc->pdev == NULL) continue; vgaarb_dbg(&uc->pdev->dev, "uc->io_cnt == %d, uc->mem_cnt == %d\n", uc->io_cnt, uc->mem_cnt); while (uc->io_cnt--) vga_put(uc->pdev, VGA_RSRC_LEGACY_IO); while (uc->mem_cnt--) vga_put(uc->pdev, VGA_RSRC_LEGACY_MEM); } spin_unlock_irqrestore(&vga_user_lock, flags); kfree(priv); return 0; } /* * callback any registered clients to let them know we have a * change in VGA cards */ static void vga_arbiter_notify_clients(void) { struct vga_device *vgadev; unsigned long flags; uint32_t new_decodes; bool new_state; if (!vga_arbiter_used) return; spin_lock_irqsave(&vga_lock, flags); list_for_each_entry(vgadev, &vga_list, list) { if (vga_count > 1) new_state = false; else new_state = true; if (vgadev->set_decode) { new_decodes = vgadev->set_decode(vgadev->pdev, new_state); vga_update_device_decodes(vgadev, new_decodes); } } spin_unlock_irqrestore(&vga_lock, flags); } static int pci_notify(struct notifier_block *nb, unsigned long action, void *data) { struct device *dev = data; struct pci_dev *pdev = to_pci_dev(dev); bool notify = false; vgaarb_dbg(dev, "%s\n", __func__); /* For now we're only intereted in devices added and removed. I didn't * test this thing here, so someone needs to double check for the * cases of hotplugable vga cards. */ if (action == BUS_NOTIFY_ADD_DEVICE) notify = vga_arbiter_add_pci_device(pdev); else if (action == BUS_NOTIFY_DEL_DEVICE) notify = vga_arbiter_del_pci_device(pdev); if (notify) vga_arbiter_notify_clients(); return 0; } static struct notifier_block pci_notifier = { .notifier_call = pci_notify, }; static const struct file_operations vga_arb_device_fops = { .read = vga_arb_read, .write = vga_arb_write, .poll = vga_arb_fpoll, .open = vga_arb_open, .release = vga_arb_release, .llseek = noop_llseek, }; static struct miscdevice vga_arb_device = { MISC_DYNAMIC_MINOR, "vga_arbiter", &vga_arb_device_fops }; static int __init vga_arb_device_init(void) { int rc; struct pci_dev *pdev; rc = misc_register(&vga_arb_device); if (rc < 0) pr_err("error %d registering device\n", rc); bus_register_notifier(&pci_bus_type, &pci_notifier); /* We add all PCI devices satisfying VGA class in the arbiter by * default */ pdev = NULL; while ((pdev = pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, pdev)) != NULL) vga_arbiter_add_pci_device(pdev); pr_info("loaded\n"); return rc; } subsys_initcall_sync(vga_arb_device_init);
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