| /* |
| * vgaarb.c |
| * |
| * (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> |
| * |
| * Implements the VGA arbitration. For details refer to |
| * Documentation/vgaarbiter.txt |
| */ |
| |
| #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/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 occured 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_devel("%s: %d\n", __func__, rsrc); |
| pr_devel("%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_devel("%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--; |
| } |
| } |
| |
| 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); |
| |
| /* return number of active VGA devices */ |
| /* 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 = -1; |
| 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 16 |
| #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 targetting 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_devel("client 0x%X called 'lock'\n", (int)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_devel("client 0x%X called 'unlock'\n", (int)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_devel("client 0x%X called 'trylock'\n", (int)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_devel("client 0x%X called 'target'\n", (int)priv); |
| /* if target is default */ |
| if (!strncmp(buf, "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_bus_and_slot(bus, devfn); |
| if (!pdev) { |
| pr_info("vgaarb: invalid PCI address!\n"); |
| ret_val = -ENODEV; |
| goto done; |
| } |
| } |
| |
| vgadev = vgadev_find(pdev); |
| if (vgadev == NULL) { |
| pr_info("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 number reached!\n"); |
| 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_devel("vgaarb: client 0x%X called 'decodes'\n", (int)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_devel("%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_devel("%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_devel("%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_devel("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_devel("%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, |
| }; |
| |
| 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); |