diff options
Diffstat (limited to 'drivers/gpu/vga/vgaarb.c')
| -rw-r--r-- | drivers/gpu/vga/vgaarb.c | 1331 |
1 files changed, 1331 insertions, 0 deletions
diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c new file mode 100644 index 00000000..111d956d --- /dev/null +++ b/drivers/gpu/vga/vgaarb.c @@ -0,0 +1,1331 @@ +/* + * 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 */ + bool bridge_has_one_vga; + /* 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; + 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; + + 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 + */ + + flags = 0; + pci_bits = 0; + + if (!conflict->bridge_has_one_vga) { + vga_irq_set_state(conflict, false); + flags |= PCI_VGA_STATE_CHANGE_DECODES; + 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; + } + + if (change_bridge) + flags |= PCI_VGA_STATE_CHANGE_BRIDGE; + + pci_set_vga_state(conflict->pdev, false, pci_bits, flags); + 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. + */ + 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); + + if (!vgadev->bridge_has_one_vga) { + 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); + +/* 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) { + if (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 = 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 + + vga_arbiter_check_bridge_sharing(vgadev); + + /* 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) { + 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) { + 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 = 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__); + + 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; + struct vga_device *vgadev; + + 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"); + + list_for_each_entry(vgadev, &vga_list, list) { + if (vgadev->bridge_has_one_vga) + pr_info("vgaarb: bridge control possible %s\n", pci_name(vgadev->pdev)); + else + pr_info("vgaarb: no bridge control possible %s\n", pci_name(vgadev->pdev)); + } + return rc; +} +subsys_initcall(vga_arb_device_init); |