/*
* vgaarb.c: Implements the VGA arbitration. For details refer to
* Documentation/vgaarbiter.txt
*
*
* (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.
*
*/
#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.h>
#include <linux/wait.h>
#include <linux/spinlock.h>
#include <linux/poll.h>
#include <linux/miscdevice.h>
#include <linux/slab.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 */
/* allow IRQ enable/disable hook */
void *cookie;
void (*irq_set_state)(void *cookie, bool enable);
unsigned int (*set_vga_decode)(void *cookie, 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;
}
#ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE
/* this is only used a cookie - it should not be dereferenced */
static struct pci_dev *vga_default;
#endif
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;
}
/* Returns the default VGA device (vgacon's babe) */
#ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE
struct pci_dev *vga_default_device(void)
{
return vga_default;
}
#endif
static inline void vga_irq_set_state(struct vga_device *vgadev, bool state)
{
if (vgadev->irq_set_state)
vgadev->irq_set_state(vgadev->cookie, state);
}
/* 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)
{
unsigned int wants, legacy_wants, match;
struct vga_device *conflict;
unsigned int pci_bits;
/* 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;
pr_debug("%s: %d\n", __func__, rsrc);
pr_debug("%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;
/* Check if the architecture allows a conflict between those
* 2 devices or if they are on separate domains
*/
if (!vga_conflicts(vgadev->pdev, conflict->pdev))
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 he owns the resource we want. We don't need
* to check "decodes" since it should be impossible to own
* own legacy resources you don't decode unless I have a bug
* in this code...
*/
WARN_ON(conflict->owns & ~conflict->decodes);
match = lwants & conflict->owns;
if (!match)
continue;
/* looks like he doesn't have a lock, we can steal
* them from him
*/
vga_irq_set_state(conflict, false);
pci_bits = 0;
if (lwants & (VGA_RSRC_LEGACY_MEM|VGA_RSRC_NORMAL_MEM))
pci_bits |= PCI_COMMAND_MEMORY;
if (lwants & (VGA_RSRC_LEGACY_IO|VGA_RSRC_NORMAL_IO))
pci_bits |= PCI_COMMAND_IO;
pci_set_vga_state(conflict->pdev, false, pci_bits,
change_bridge);
conflict->owns &= ~lwants;
/* If he also owned non-legacy, that is no longer the case */
if (lwants & VGA_RSRC_LEGACY_MEM)
conflict->owns &= ~VGA_RSRC_NORMAL_MEM;
if (lwants & VGA_RSRC_LEGACY_IO)
conflict->owns &= ~VGA_RSRC_NORMAL_IO;
}
enable_them:
/* ok dude, we got it, everybody conflicting has been disabled, let's
* enable us. Make sure we don't mark a bit in "owns" that we don't
* also have in "decodes". We can lock resources we don't decode but
* not own them.
*/
pci_bits = 0;
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;
pci_set_vga_state(vgadev->pdev, true, pci_bits, !!(wants & VGA_RSRC_LEGACY_MASK));
vga_irq_set_state(vgadev, true);
vgadev->owns |= (wants & vgadev->decodes);
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)
{
unsigned int old_locks = vgadev->locks;
pr_debug("%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);
}
int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible)
{
struct vga_device *vgadev, *conflict;
unsigned long flags;
wait_queue_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 (signal_pending(current)) {
rc = -EINTR;
break;
}
schedule();
remove_wait_queue(&vga_wait_queue, &wait);
set_current_state(TASK_RUNNING);
}
return rc;
}
EXPORT_SYMBOL(vga_get);
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;
}
EXPORT_SYMBOL(vga_tryget);
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);
/*
* 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 = kmalloc(sizeof(struct vga_device), GFP_KERNEL);
if (vgadev == NULL) {
pr_err("vgaarb: failed to allocate pci device\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;
}
memset(vgadev, 0, sizeof(*vgadev));
/* 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
*/
#ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE
if (vga_default == NULL &&
((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK))
vga_default = pci_dev_get(pdev);
#endif
/* Add to the list */
list_add(&vgadev->list, &vga_list);
vga_count++;
pr_info("vgaarb: device added: PCI:%s,decodes=%s,owns=%s,locks=%s\n",
pci_name(pdev),
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) {
pci_dev_put(vga_default);
vga_default = 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)
{
int old_decodes;
struct vga_device *new_vgadev, *conflict;
old_decodes = vgadev->decodes;
vgadev->decodes = new_decodes;
pr_info("vgaarb: device changed decodes: PCI:%s,olddecodes=%s,decodes=%s:owns=%s\n",
pci_name(vgadev->pdev),
vga_iostate_to_str(old_decodes),
vga_iostate_to_str(vgadev->decodes),
vga_iostate_to_str(vgadev->owns));
/* if we own the decodes we should move them along to
another card */
if ((vgadev->owns & old_decodes) && (vga_count > 1)) {
/* set us to own nothing */
vgadev->owns &= ~old_decodes;
list_for_each_entry(new_vgadev, &vga_list, list) {
if ((new_vgadev != vgadev) &&
(new_vgadev->decodes & VGA_RSRC_LEGACY_MASK)) {
pr_info("vgaarb: transferring owner from PCI:%s to PCI:%s\n", pci_name(vgadev->pdev), pci_name(new_vgadev->pdev));
conflict = __vga_tryget(new_vgadev, VGA_RSRC_LEGACY_MASK);
if (!conflict)
__vga_put(new_vgadev, VGA_RSRC_LEGACY_MASK);
break;
}
}
}
/* change decodes counter */
if (old_decodes != new_decodes) {
if (new_decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM))
vga_decode_count++;
else
vga_decode_count--;
}
pr_debug("vgaarb: 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_vga_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);
}
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);
/* call with NULL to unregister */
int vga_client_register(struct pci_dev *pdev, void *cookie,
void (*irq_set_state)(void *cookie, bool state),
unsigned int (*set_vga_decode)(void *cookie, 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->irq_set_state = irq_set_state;
vgadev->set_vga_decode = set_vga_decode;
vgadev->cookie = cookie;
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, *curr_pos;
size_t remaining = count;
int ret_val;
int i;
kbuf = kmalloc(count + 1, GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
if (copy_from_user(kbuf, buf, count)) {
kfree(kbuf);
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)
return -EINVAL;
if (io_state & VGA_RSRC_LEGACY_IO && uc->io_cnt == 0)
return -EINVAL;
if (io_state & VGA_RSRC_LEGACY_MEM && uc->mem_cnt == 0)
return -EINVAL;
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) {
struct pci_bus *pbus;
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;
}
pr_debug("vgaarb: %s ==> %x:%x:%x.%x\n", curr_pos,
domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn));
pbus = pci_find_bus(domain, bus);
pr_debug("vgaarb: pbus %p\n", pbus);
if (pbus == NULL) {
pr_err("vgaarb: invalid PCI domain and/or bus address %x:%x\n",
domain, bus);
ret_val = -ENODEV;
goto done;
}
pdev = pci_get_slot(pbus, devfn);
pr_debug("vgaarb: pdev %p\n", pdev);
if (!pdev) {
pr_err("vgaarb: invalid PCI address %x:%x\n",
bus, devfn);
ret_val = -ENODEV;
goto done;
}
}
vgadev = vgadev_find(pdev);
pr_debug("vgaarb: vgadev %p\n", vgadev);
if (vgadev == NULL) {
pr_err("vgaarb: this pci device is 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) {
pr_err("vgaarb: maximum user cards (%d) number reached!\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("vgaarb: 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! */
kfree(kbuf);
return -EPROTO;
done:
kfree(kbuf);
return ret_val;
}
static unsigned int vga_arb_fpoll(struct file *file, poll_table * wait)
{
struct vga_arb_private *priv = file->private_data;
pr_debug("%s\n", __func__);
if (priv == NULL)
return -ENODEV;
poll_wait(file, &vga_wait_queue, wait);
return POLLIN;
}
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 = kmalloc(sizeof(struct vga_arb_private), GFP_KERNEL);
if (priv == NULL)
return -ENOMEM;
memset(priv, 0, sizeof(*priv));
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__);
if (priv == NULL)
return -ENODEV;
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;
pr_debug("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_vga_decode) {
new_decodes = vgadev->set_vga_decode(vgadev->cookie, 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;
pr_debug("%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("vgaarb: 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("vgaarb: loaded\n");
return rc;
}
subsys_initcall(vga_arb_device_init);