.. kernel-doc:: include/linux/vgaarb.h
:internal:
-.. kernel-doc:: drivers/gpu/vga/vgaarb.c
+.. kernel-doc:: drivers/pci/vgaarb.c
:export:
libpciaccess
# SPDX-License-Identifier: GPL-2.0-only
-config VGA_ARB
- bool "VGA Arbitration" if EXPERT
- default y
- depends on (PCI && !S390)
- help
- Some "legacy" VGA devices implemented on PCI typically have the same
- hard-decoded addresses as they did on ISA. When multiple PCI devices
- are accessed at same time they need some kind of coordination. Please
- see Documentation/gpu/vgaarbiter.rst for more details. Select this to
- enable VGA arbiter.
-
-config VGA_ARB_MAX_GPUS
- int "Maximum number of GPUs"
- default 16
- depends on VGA_ARB
- help
- Reserves space in the kernel to maintain resource locking for
- multiple GPUS. The overhead for each GPU is very small.
-
config VGA_SWITCHEROO
bool "Laptop Hybrid Graphics - GPU switching support"
depends on X86
# SPDX-License-Identifier: GPL-2.0-only
-obj-$(CONFIG_VGA_ARB) += vgaarb.o
obj-$(CONFIG_VGA_SWITCHEROO) += vga_switcheroo.o
+++ /dev/null
-/*
- * 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>
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice (including the next
- * paragraph) shall be included in all copies or substantial portions of the
- * Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS
- * IN THE SOFTWARE.
- *
- */
-
-#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;
- 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;
-
-static void vga_arb_device_card_gone(struct pci_dev *pdev);
-
-/* 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);
-
-/*
- * 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))
- 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;
- }
-}
-
-/*
- * 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;
- }
-
- /* Deal with VGA default device. Use first enabled one
- * by default if arch doesn't have it's own hook
- */
- if (vga_default == NULL &&
- ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) {
- vgaarb_info(&pdev->dev, "setting as boot VGA device\n");
- 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--;
- /* Notify userland driver that the device is gone so it discards
- * it's copies of the pci_dev pointer
- */
- vga_arb_device_card_gone(pdev);
-
- /* 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;
-
- /* Shields against vga_arb_device_card_gone (pci_dev going
- * away), and allows access to 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
- */
- if (pdev == priv->target)
- vga_arb_device_card_gone(pdev);
- 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(%d:%d)\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;
-}
-
-static void vga_arb_device_card_gone(struct pci_dev *pdev)
-{
-}
-
-/*
- * 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
-};
-
-#if defined(CONFIG_ACPI)
-static bool vga_arb_integrated_gpu(struct device *dev)
-{
- struct acpi_device *adev = ACPI_COMPANION(dev);
-
- return adev && !strcmp(acpi_device_hid(adev), ACPI_VIDEO_HID);
-}
-#else
-static bool vga_arb_integrated_gpu(struct device *dev)
-{
- return false;
-}
-#endif
-
-static void __init vga_arb_select_default_device(void)
-{
- struct pci_dev *pdev, *found = NULL;
- struct vga_device *vgadev;
-
-#if defined(CONFIG_X86) || defined(CONFIG_IA64)
- u64 base = screen_info.lfb_base;
- u64 size = screen_info.lfb_size;
- u64 limit;
- resource_size_t start, end;
- unsigned long flags;
- int i;
-
- if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
- base |= (u64)screen_info.ext_lfb_base << 32;
-
- limit = base + size;
-
- list_for_each_entry(vgadev, &vga_list, list) {
- struct device *dev = &vgadev->pdev->dev;
- /*
- * Override vga_arbiter_add_pci_device()'s I/O based detection
- * as it may take the wrong device (e.g. on Apple system under
- * EFI).
- *
- * Select the device owning the boot framebuffer if there is
- * one.
- */
-
- /* Does firmware framebuffer belong to us? */
- for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
- flags = pci_resource_flags(vgadev->pdev, i);
-
- if ((flags & IORESOURCE_MEM) == 0)
- continue;
-
- start = pci_resource_start(vgadev->pdev, i);
- end = pci_resource_end(vgadev->pdev, i);
-
- if (!start || !end)
- continue;
-
- if (base < start || limit >= end)
- continue;
-
- if (!vga_default_device())
- vgaarb_info(dev, "setting as boot device\n");
- else if (vgadev->pdev != vga_default_device())
- vgaarb_info(dev, "overriding boot device\n");
- vga_set_default_device(vgadev->pdev);
- }
- }
-#endif
-
- if (!vga_default_device()) {
- list_for_each_entry_reverse(vgadev, &vga_list, list) {
- struct device *dev = &vgadev->pdev->dev;
- u16 cmd;
-
- pdev = vgadev->pdev;
- pci_read_config_word(pdev, PCI_COMMAND, &cmd);
- if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) {
- found = pdev;
- if (vga_arb_integrated_gpu(dev))
- break;
- }
- }
- }
-
- if (found) {
- vgaarb_info(&found->dev, "setting as boot device (VGA legacy resources not available)\n");
- vga_set_default_device(found);
- return;
- }
-
- if (!vga_default_device()) {
- vgadev = list_first_entry_or_null(&vga_list,
- struct vga_device, list);
- if (vgadev) {
- struct device *dev = &vgadev->pdev->dev;
- vgaarb_info(dev, "setting as boot device (VGA legacy resources not available)\n");
- vga_set_default_device(vgadev->pdev);
- }
- }
-}
-
-static int __init vga_arb_device_init(void)
-{
- int rc;
- struct pci_dev *pdev;
- struct vga_device *vgadev;
-
- 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);
-
- list_for_each_entry(vgadev, &vga_list, list) {
- struct device *dev = &vgadev->pdev->dev;
-
- if (vgadev->bridge_has_one_vga)
- vgaarb_info(dev, "bridge control possible\n");
- else
- vgaarb_info(dev, "no bridge control possible\n");
- }
-
- vga_arb_select_default_device();
-
- pr_info("loaded\n");
- return rc;
-}
-subsys_initcall(vga_arb_device_init);
endchoice
+config VGA_ARB
+ bool "VGA Arbitration" if EXPERT
+ default y
+ depends on (PCI && !S390)
+ help
+ Some "legacy" VGA devices implemented on PCI typically have the same
+ hard-decoded addresses as they did on ISA. When multiple PCI devices
+ are accessed at same time they need some kind of coordination. Please
+ see Documentation/gpu/vgaarbiter.rst for more details. Select this to
+ enable VGA arbiter.
+
+config VGA_ARB_MAX_GPUS
+ int "Maximum number of GPUs"
+ default 16
+ depends on VGA_ARB
+ help
+ Reserves space in the kernel to maintain resource locking for
+ multiple GPUS. The overhead for each GPU is very small.
+
source "drivers/pci/hotplug/Kconfig"
source "drivers/pci/controller/Kconfig"
source "drivers/pci/endpoint/Kconfig"
obj-$(CONFIG_PCI_ECAM) += ecam.o
obj-$(CONFIG_PCI_P2PDMA) += p2pdma.o
obj-$(CONFIG_XEN_PCIDEV_FRONTEND) += xen-pcifront.o
+obj-$(CONFIG_VGA_ARB) += vgaarb.o
# Endpoint library must be initialized before its users
obj-$(CONFIG_PCI_ENDPOINT) += endpoint/
--- /dev/null
+/*
+ * 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>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#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;
+ 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;
+
+static void vga_arb_device_card_gone(struct pci_dev *pdev);
+
+/* 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);
+
+/*
+ * 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))
+ 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;
+ }
+}
+
+/*
+ * 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;
+ }
+
+ /* Deal with VGA default device. Use first enabled one
+ * by default if arch doesn't have it's own hook
+ */
+ if (vga_default == NULL &&
+ ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) {
+ vgaarb_info(&pdev->dev, "setting as boot VGA device\n");
+ 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--;
+ /* Notify userland driver that the device is gone so it discards
+ * it's copies of the pci_dev pointer
+ */
+ vga_arb_device_card_gone(pdev);
+
+ /* 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;
+
+ /* Shields against vga_arb_device_card_gone (pci_dev going
+ * away), and allows access to 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
+ */
+ if (pdev == priv->target)
+ vga_arb_device_card_gone(pdev);
+ 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(%d:%d)\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;
+}
+
+static void vga_arb_device_card_gone(struct pci_dev *pdev)
+{
+}
+
+/*
+ * 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
+};
+
+#if defined(CONFIG_ACPI)
+static bool vga_arb_integrated_gpu(struct device *dev)
+{
+ struct acpi_device *adev = ACPI_COMPANION(dev);
+
+ return adev && !strcmp(acpi_device_hid(adev), ACPI_VIDEO_HID);
+}
+#else
+static bool vga_arb_integrated_gpu(struct device *dev)
+{
+ return false;
+}
+#endif
+
+static void __init vga_arb_select_default_device(void)
+{
+ struct pci_dev *pdev, *found = NULL;
+ struct vga_device *vgadev;
+
+#if defined(CONFIG_X86) || defined(CONFIG_IA64)
+ u64 base = screen_info.lfb_base;
+ u64 size = screen_info.lfb_size;
+ u64 limit;
+ resource_size_t start, end;
+ unsigned long flags;
+ int i;
+
+ if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
+ base |= (u64)screen_info.ext_lfb_base << 32;
+
+ limit = base + size;
+
+ list_for_each_entry(vgadev, &vga_list, list) {
+ struct device *dev = &vgadev->pdev->dev;
+ /*
+ * Override vga_arbiter_add_pci_device()'s I/O based detection
+ * as it may take the wrong device (e.g. on Apple system under
+ * EFI).
+ *
+ * Select the device owning the boot framebuffer if there is
+ * one.
+ */
+
+ /* Does firmware framebuffer belong to us? */
+ for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
+ flags = pci_resource_flags(vgadev->pdev, i);
+
+ if ((flags & IORESOURCE_MEM) == 0)
+ continue;
+
+ start = pci_resource_start(vgadev->pdev, i);
+ end = pci_resource_end(vgadev->pdev, i);
+
+ if (!start || !end)
+ continue;
+
+ if (base < start || limit >= end)
+ continue;
+
+ if (!vga_default_device())
+ vgaarb_info(dev, "setting as boot device\n");
+ else if (vgadev->pdev != vga_default_device())
+ vgaarb_info(dev, "overriding boot device\n");
+ vga_set_default_device(vgadev->pdev);
+ }
+ }
+#endif
+
+ if (!vga_default_device()) {
+ list_for_each_entry_reverse(vgadev, &vga_list, list) {
+ struct device *dev = &vgadev->pdev->dev;
+ u16 cmd;
+
+ pdev = vgadev->pdev;
+ pci_read_config_word(pdev, PCI_COMMAND, &cmd);
+ if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) {
+ found = pdev;
+ if (vga_arb_integrated_gpu(dev))
+ break;
+ }
+ }
+ }
+
+ if (found) {
+ vgaarb_info(&found->dev, "setting as boot device (VGA legacy resources not available)\n");
+ vga_set_default_device(found);
+ return;
+ }
+
+ if (!vga_default_device()) {
+ vgadev = list_first_entry_or_null(&vga_list,
+ struct vga_device, list);
+ if (vgadev) {
+ struct device *dev = &vgadev->pdev->dev;
+ vgaarb_info(dev, "setting as boot device (VGA legacy resources not available)\n");
+ vga_set_default_device(vgadev->pdev);
+ }
+ }
+}
+
+static int __init vga_arb_device_init(void)
+{
+ int rc;
+ struct pci_dev *pdev;
+ struct vga_device *vgadev;
+
+ 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);
+
+ list_for_each_entry(vgadev, &vga_list, list) {
+ struct device *dev = &vgadev->pdev->dev;
+
+ if (vgadev->bridge_has_one_vga)
+ vgaarb_info(dev, "bridge control possible\n");
+ else
+ vgaarb_info(dev, "no bridge control possible\n");
+ }
+
+ vga_arb_select_default_device();
+
+ pr_info("loaded\n");
+ return rc;
+}
+subsys_initcall_sync(vga_arb_device_init);
projects / platform / kernel / linux-starfive.git / commitdiff