From 4db3189ce0621be901f249f8cd8226c977dd601d Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Thu, 24 Feb 2022 14:24:25 +0100 Subject: drm/todo: Update panic handling todo Some things changed, and add two useful links. v2: Also include a link to the QR encoding work. Plus review from Javier. v3: Fix typo Guilherme spotted. Reviewed-by: Guilherme G. Piccoli Acked-by: Pekka Paalanen Reviewed-by: Javier Martinez Canillas Cc: Javier Martinez Canillas Cc: Pekka Paalanen Cc: gpiccoli@igalia.com Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20220224132425.3463791-1-daniel.vetter@ffwll.ch --- Documentation/gpu/todo.rst | 25 ++++++++++++++----------- 1 file changed, 14 insertions(+), 11 deletions(-) (limited to 'Documentation/gpu') diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst index 1b2372ef4131..d6a7ebf717be 100644 --- a/Documentation/gpu/todo.rst +++ b/Documentation/gpu/todo.rst @@ -499,8 +499,12 @@ This is a really varied tasks with lots of little bits and pieces: achieved by using an IPI to the local processor. * There's a massive confusion of different panic handlers. DRM fbdev emulation - helpers have one, but on top of that the fbcon code itself also has one. We - need to make sure that they stop fighting over each another. + helpers had their own (long removed), but on top of that the fbcon code itself + also has one. We need to make sure that they stop fighting over each other. + This is worked around by checking ``oops_in_progress`` at various entry points + into the DRM fbdev emulation helpers. A much cleaner approach here would be to + switch fbcon to the `threaded printk support + `_. * ``drm_can_sleep()`` is a mess. It hides real bugs in normal operations and isn't a full solution for panic paths. We need to make sure that it only @@ -512,16 +516,15 @@ This is a really varied tasks with lots of little bits and pieces: even spinlocks (because NMI and hardirq can panic too). We need to either make sure to not call such paths, or trylock everything. Really tricky. -* For the above locking troubles reasons it's pretty much impossible to - attempt a synchronous modeset from panic handlers. The only thing we could - try to achive is an atomic ``set_base`` of the primary plane, and hope that - it shows up. Everything else probably needs to be delayed to some worker or - something else which happens later on. Otherwise it just kills the box - harder, prevent the panic from going out on e.g. netconsole. +* A clean solution would be an entirely separate panic output support in KMS, + bypassing the current fbcon support. See `[PATCH v2 0/3] drm: Add panic handling + `_. -* There's also proposal for a simplied DRM console instead of the full-blown - fbcon and DRM fbdev emulation. Any kind of panic handling tricks should - obviously work for both console, in case we ever get kmslog merged. +* Encoding the actual oops and preceding dmesg in a QR might help with the + dread "important stuff scrolled away" problem. See `[RFC][PATCH] Oops messages + transfer using QR codes + `_ + for some example code that could be reused. Contact: Daniel Vetter -- cgit 1.4.1 From 9ae2ac4d31a85ce59cc560d514a31b95f4ace154 Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Wed, 23 Feb 2022 20:38:04 +0100 Subject: drm: Add TODO item for optimizing format helpers Add a TODO item for optimizing blitting and format-conversion helpers in DRM and fbdev. There's always demand for faster graphics output. v4: * fix typos (Sam) Signed-off-by: Thomas Zimmermann Reviewed-by: Javier Martinez Canillas Acked-by: Sam Ravnborg Link: https://patchwork.freedesktop.org/patch/msgid/20220223193804.18636-6-tzimmermann@suse.de --- Documentation/gpu/todo.rst | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'Documentation/gpu') diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst index d6a7ebf717be..4260c62d751b 100644 --- a/Documentation/gpu/todo.rst +++ b/Documentation/gpu/todo.rst @@ -241,6 +241,28 @@ Contact: Thomas Zimmermann , Daniel Vetter Level: Advanced +Benchmark and optimize blitting and format-conversion function +-------------------------------------------------------------- + +Drawing to dispay memory quickly is crucial for many applications' +performance. + +On at least x86-64, sys_imageblit() is significantly slower than +cfb_imageblit(), even though both use the same blitting algorithm and +the latter is written for I/O memory. It turns out that cfb_imageblit() +uses movl instructions, while sys_imageblit apparently does not. This +seems to be a problem with gcc's optimizer. DRM's format-conversion +helpers might be subject to similar issues. + +Benchmark and optimize fbdev's sys_() helpers and DRM's format-conversion +helpers. In cases that can be further optimized, maybe implement a different +algorithm. For micro-optimizations, use movl/movq instructions explicitly. +That might possibly require architecture-specific helpers (e.g., storel() +storeq()). + +Contact: Thomas Zimmermann + +Level: Intermediate drm_framebuffer_funcs and drm_mode_config_funcs.fb_create cleanup ----------------------------------------------------------------- -- cgit 1.4.1 From 07b58d61275ebbb39b678d18f7c4e472050b13eb Mon Sep 17 00:00:00 2001 From: Matthew Auld Date: Tue, 8 Feb 2022 15:12:28 +0000 Subject: drm/doc: pull in drm_buddy.c MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Make sure we pull in the kernel-doc for this. Reported-by: Daniel Vetter Signed-off-by: Matthew Auld Cc: Arunpravin Cc: Christian König Link: https://patchwork.freedesktop.org/patch/msgid/20220208151228.344997-1-matthew.auld@intel.com Signed-off-by: Christian König Reviewed-by: Christian König --- Documentation/gpu/drm-mm.rst | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'Documentation/gpu') diff --git a/Documentation/gpu/drm-mm.rst b/Documentation/gpu/drm-mm.rst index 198bcc1affa1..f32ccce5722d 100644 --- a/Documentation/gpu/drm-mm.rst +++ b/Documentation/gpu/drm-mm.rst @@ -466,6 +466,15 @@ DRM MM Range Allocator Function References .. kernel-doc:: drivers/gpu/drm/drm_mm.c :export: +DRM Buddy Allocator +=================== + +DRM Buddy Function References +----------------------------- + +.. kernel-doc:: drivers/gpu/drm/drm_buddy.c + :export: + DRM Cache Handling and Fast WC memcpy() ======================================= -- cgit 1.4.1 From 1d38fe6ee6a874675ca3bba6b48e69a0e6176ffc Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Thu, 24 Feb 2022 16:47:43 -0600 Subject: PCI/VGA: Move vgaarb to drivers/pci The VGA arbiter is really PCI-specific and doesn't depend on any GPU things. Move it to the PCI subsystem. Note that misc_init() must be called before vga_arb_device_init(). These are both subsys_initcalls, so this ordering depends on the link order, which is determined by drivers/Makefile: obj-y += pci/ obj-y += char/ <-- misc_init() obj-y += gpu/ <-- vga_arb_device_init() (before this commit) The drivers/pci/ subsys_initcalls are called *before* misc_init(), so convert vga_arb_device_init() to subsys_initcall_sync(), which is called after *all* subsys_initcalls. Link: https://lore.kernel.org/r/20220224224753.297579-2-helgaas@kernel.org Signed-off-by: Bjorn Helgaas --- Documentation/gpu/vgaarbiter.rst | 2 +- drivers/gpu/vga/Kconfig | 19 - drivers/gpu/vga/Makefile | 1 - drivers/gpu/vga/vgaarb.c | 1567 -------------------------------------- drivers/pci/Kconfig | 19 + drivers/pci/Makefile | 1 + drivers/pci/vgaarb.c | 1567 ++++++++++++++++++++++++++++++++++++++ 7 files changed, 1588 insertions(+), 1588 deletions(-) delete mode 100644 drivers/gpu/vga/vgaarb.c create mode 100644 drivers/pci/vgaarb.c (limited to 'Documentation/gpu') diff --git a/Documentation/gpu/vgaarbiter.rst b/Documentation/gpu/vgaarbiter.rst index 339ed5fecd2e..bde3c0afb059 100644 --- a/Documentation/gpu/vgaarbiter.rst +++ b/Documentation/gpu/vgaarbiter.rst @@ -100,7 +100,7 @@ In-kernel interface .. kernel-doc:: include/linux/vgaarb.h :internal: -.. kernel-doc:: drivers/gpu/vga/vgaarb.c +.. kernel-doc:: drivers/pci/vgaarb.c :export: libpciaccess diff --git a/drivers/gpu/vga/Kconfig b/drivers/gpu/vga/Kconfig index 1ad4c4ef0b5e..eb8b14ab22c3 100644 --- a/drivers/gpu/vga/Kconfig +++ b/drivers/gpu/vga/Kconfig @@ -1,23 +1,4 @@ # SPDX-License-Identifier: GPL-2.0-only -config VGA_ARB - bool "VGA Arbitration" if EXPERT - default y - depends on (PCI && !S390) - help - Some "legacy" VGA devices implemented on PCI typically have the same - hard-decoded addresses as they did on ISA. When multiple PCI devices - are accessed at same time they need some kind of coordination. Please - see Documentation/gpu/vgaarbiter.rst for more details. Select this to - enable VGA arbiter. - -config VGA_ARB_MAX_GPUS - int "Maximum number of GPUs" - default 16 - depends on VGA_ARB - help - Reserves space in the kernel to maintain resource locking for - multiple GPUS. The overhead for each GPU is very small. - config VGA_SWITCHEROO bool "Laptop Hybrid Graphics - GPU switching support" depends on X86 diff --git a/drivers/gpu/vga/Makefile b/drivers/gpu/vga/Makefile index e92064442d60..9800620deda3 100644 --- a/drivers/gpu/vga/Makefile +++ b/drivers/gpu/vga/Makefile @@ -1,3 +1,2 @@ # SPDX-License-Identifier: GPL-2.0-only -obj-$(CONFIG_VGA_ARB) += vgaarb.o obj-$(CONFIG_VGA_SWITCHEROO) += vga_switcheroo.o diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c deleted file mode 100644 index 569930552957..000000000000 --- a/drivers/gpu/vga/vgaarb.c +++ /dev/null @@ -1,1567 +0,0 @@ -/* - * vgaarb.c: Implements the VGA arbitration. For details refer to - * Documentation/gpu/vgaarbiter.rst - * - * - * (C) Copyright 2005 Benjamin Herrenschmidt - * (C) Copyright 2007 Paulo R. Zanoni - * (C) Copyright 2007, 2009 Tiago Vignatti - * - * Permission is hereby granted, free of charge, to any person obtaining a - * copy of this software and associated documentation files (the "Software"), - * to deal in the Software without restriction, including without limitation - * the rights to use, copy, modify, merge, publish, distribute, sublicense, - * and/or sell copies of the Software, and to permit persons to whom the - * Software is furnished to do so, subject to the following conditions: - * - * The above copyright notice and this permission notice (including the next - * paragraph) shall be included in all copies or substantial portions of the - * Software. - * - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR - * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL - * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER - * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING - * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER - * DEALINGS - * IN THE SOFTWARE. - * - */ - -#define pr_fmt(fmt) "vgaarb: " fmt - -#define vgaarb_dbg(dev, fmt, arg...) dev_dbg(dev, "vgaarb: " fmt, ##arg) -#define vgaarb_info(dev, fmt, arg...) dev_info(dev, "vgaarb: " fmt, ##arg) -#define vgaarb_err(dev, fmt, arg...) dev_err(dev, "vgaarb: " fmt, ##arg) - -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#include - -#include - -static void vga_arbiter_notify_clients(void); -/* - * We keep a list of all vga devices in the system to speed - * up the various operations of the arbiter - */ -struct vga_device { - struct list_head list; - struct pci_dev *pdev; - unsigned int decodes; /* what does it decodes */ - unsigned int owns; /* what does it owns */ - unsigned int locks; /* what does it locks */ - unsigned int io_lock_cnt; /* legacy IO lock count */ - unsigned int mem_lock_cnt; /* legacy MEM lock count */ - unsigned int io_norm_cnt; /* normal IO count */ - unsigned int mem_norm_cnt; /* normal MEM count */ - bool bridge_has_one_vga; - unsigned int (*set_decode)(struct pci_dev *pdev, bool decode); -}; - -static LIST_HEAD(vga_list); -static int vga_count, vga_decode_count; -static bool vga_arbiter_used; -static DEFINE_SPINLOCK(vga_lock); -static DECLARE_WAIT_QUEUE_HEAD(vga_wait_queue); - - -static const char *vga_iostate_to_str(unsigned int iostate) -{ - /* Ignore VGA_RSRC_IO and VGA_RSRC_MEM */ - iostate &= VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; - switch (iostate) { - case VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM: - return "io+mem"; - case VGA_RSRC_LEGACY_IO: - return "io"; - case VGA_RSRC_LEGACY_MEM: - return "mem"; - } - return "none"; -} - -static int vga_str_to_iostate(char *buf, int str_size, int *io_state) -{ - /* we could in theory hand out locks on IO and mem - * separately to userspace but it can cause deadlocks */ - if (strncmp(buf, "none", 4) == 0) { - *io_state = VGA_RSRC_NONE; - return 1; - } - - /* XXX We're not chekcing the str_size! */ - if (strncmp(buf, "io+mem", 6) == 0) - goto both; - else if (strncmp(buf, "io", 2) == 0) - goto both; - else if (strncmp(buf, "mem", 3) == 0) - goto both; - return 0; -both: - *io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; - return 1; -} - -/* this is only used a cookie - it should not be dereferenced */ -static struct pci_dev *vga_default; - -static void vga_arb_device_card_gone(struct pci_dev *pdev); - -/* Find somebody in our list */ -static struct vga_device *vgadev_find(struct pci_dev *pdev) -{ - struct vga_device *vgadev; - - list_for_each_entry(vgadev, &vga_list, list) - if (pdev == vgadev->pdev) - return vgadev; - return NULL; -} - -/** - * vga_default_device - return the default VGA device, for vgacon - * - * This can be defined by the platform. The default implementation - * is rather dumb and will probably only work properly on single - * vga card setups and/or x86 platforms. - * - * If your VGA default device is not PCI, you'll have to return - * NULL here. In this case, I assume it will not conflict with - * any PCI card. If this is not true, I'll have to define two archs - * hooks for enabling/disabling the VGA default device if that is - * possible. This may be a problem with real _ISA_ VGA cards, in - * addition to a PCI one. I don't know at this point how to deal - * with that card. Can theirs IOs be disabled at all ? If not, then - * I suppose it's a matter of having the proper arch hook telling - * us about it, so we basically never allow anybody to succeed a - * vga_get()... - */ -struct pci_dev *vga_default_device(void) -{ - return vga_default; -} -EXPORT_SYMBOL_GPL(vga_default_device); - -void vga_set_default_device(struct pci_dev *pdev) -{ - if (vga_default == pdev) - return; - - pci_dev_put(vga_default); - vga_default = pci_dev_get(pdev); -} - -/** - * vga_remove_vgacon - deactivete vga console - * - * Unbind and unregister vgacon in case pdev is the default vga - * device. Can be called by gpu drivers on initialization to make - * sure vga register access done by vgacon will not disturb the - * device. - * - * @pdev: pci device. - */ -#if !defined(CONFIG_VGA_CONSOLE) -int vga_remove_vgacon(struct pci_dev *pdev) -{ - return 0; -} -#elif !defined(CONFIG_DUMMY_CONSOLE) -int vga_remove_vgacon(struct pci_dev *pdev) -{ - return -ENODEV; -} -#else -int vga_remove_vgacon(struct pci_dev *pdev) -{ - int ret = 0; - - if (pdev != vga_default) - return 0; - vgaarb_info(&pdev->dev, "deactivate vga console\n"); - - console_lock(); - if (con_is_bound(&vga_con)) - ret = do_take_over_console(&dummy_con, 0, - MAX_NR_CONSOLES - 1, 1); - if (ret == 0) { - ret = do_unregister_con_driver(&vga_con); - - /* Ignore "already unregistered". */ - if (ret == -ENODEV) - ret = 0; - } - console_unlock(); - - return ret; -} -#endif -EXPORT_SYMBOL(vga_remove_vgacon); - -/* If we don't ever use VGA arb we should avoid - turning off anything anywhere due to old X servers getting - confused about the boot device not being VGA */ -static void vga_check_first_use(void) -{ - /* we should inform all GPUs in the system that - * VGA arb has occurred and to try and disable resources - * if they can */ - if (!vga_arbiter_used) { - vga_arbiter_used = true; - vga_arbiter_notify_clients(); - } -} - -static struct vga_device *__vga_tryget(struct vga_device *vgadev, - unsigned int rsrc) -{ - struct device *dev = &vgadev->pdev->dev; - unsigned int wants, legacy_wants, match; - struct vga_device *conflict; - unsigned int pci_bits; - u32 flags = 0; - - /* Account for "normal" resources to lock. If we decode the legacy, - * counterpart, we need to request it as well - */ - if ((rsrc & VGA_RSRC_NORMAL_IO) && - (vgadev->decodes & VGA_RSRC_LEGACY_IO)) - rsrc |= VGA_RSRC_LEGACY_IO; - if ((rsrc & VGA_RSRC_NORMAL_MEM) && - (vgadev->decodes & VGA_RSRC_LEGACY_MEM)) - rsrc |= VGA_RSRC_LEGACY_MEM; - - vgaarb_dbg(dev, "%s: %d\n", __func__, rsrc); - vgaarb_dbg(dev, "%s: owns: %d\n", __func__, vgadev->owns); - - /* Check what resources we need to acquire */ - wants = rsrc & ~vgadev->owns; - - /* We already own everything, just mark locked & bye bye */ - if (wants == 0) - goto lock_them; - - /* We don't need to request a legacy resource, we just enable - * appropriate decoding and go - */ - legacy_wants = wants & VGA_RSRC_LEGACY_MASK; - if (legacy_wants == 0) - goto enable_them; - - /* Ok, we don't, let's find out how we need to kick off */ - list_for_each_entry(conflict, &vga_list, list) { - unsigned int lwants = legacy_wants; - unsigned int change_bridge = 0; - - /* Don't conflict with myself */ - if (vgadev == conflict) - continue; - - /* We have a possible conflict. before we go further, we must - * check if we sit on the same bus as the conflicting device. - * if we don't, then we must tie both IO and MEM resources - * together since there is only a single bit controlling - * VGA forwarding on P2P bridges - */ - if (vgadev->pdev->bus != conflict->pdev->bus) { - change_bridge = 1; - lwants = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; - } - - /* Check if the guy has a lock on the resource. If he does, - * return the conflicting entry - */ - if (conflict->locks & lwants) - return conflict; - - /* Ok, now check if it owns the resource we want. We can - * lock resources that are not decoded, therefore a device - * can own resources it doesn't decode. - */ - match = lwants & conflict->owns; - if (!match) - continue; - - /* looks like he doesn't have a lock, we can steal - * them from him - */ - - flags = 0; - pci_bits = 0; - - /* If we can't control legacy resources via the bridge, we - * also need to disable normal decoding. - */ - if (!conflict->bridge_has_one_vga) { - if ((match & conflict->decodes) & VGA_RSRC_LEGACY_MEM) - pci_bits |= PCI_COMMAND_MEMORY; - if ((match & conflict->decodes) & VGA_RSRC_LEGACY_IO) - pci_bits |= PCI_COMMAND_IO; - - if (pci_bits) - flags |= PCI_VGA_STATE_CHANGE_DECODES; - } - - if (change_bridge) - flags |= PCI_VGA_STATE_CHANGE_BRIDGE; - - pci_set_vga_state(conflict->pdev, false, pci_bits, flags); - conflict->owns &= ~match; - - /* If we disabled normal decoding, reflect it in owns */ - if (pci_bits & PCI_COMMAND_MEMORY) - conflict->owns &= ~VGA_RSRC_NORMAL_MEM; - if (pci_bits & PCI_COMMAND_IO) - conflict->owns &= ~VGA_RSRC_NORMAL_IO; - } - -enable_them: - /* ok dude, we got it, everybody conflicting has been disabled, let's - * enable us. Mark any bits in "owns" regardless of whether we - * decoded them. We can lock resources we don't decode, therefore - * we must track them via "owns". - */ - flags = 0; - pci_bits = 0; - - if (!vgadev->bridge_has_one_vga) { - flags |= PCI_VGA_STATE_CHANGE_DECODES; - if (wants & (VGA_RSRC_LEGACY_MEM|VGA_RSRC_NORMAL_MEM)) - pci_bits |= PCI_COMMAND_MEMORY; - if (wants & (VGA_RSRC_LEGACY_IO|VGA_RSRC_NORMAL_IO)) - pci_bits |= PCI_COMMAND_IO; - } - if (wants & VGA_RSRC_LEGACY_MASK) - flags |= PCI_VGA_STATE_CHANGE_BRIDGE; - - pci_set_vga_state(vgadev->pdev, true, pci_bits, flags); - - vgadev->owns |= wants; -lock_them: - vgadev->locks |= (rsrc & VGA_RSRC_LEGACY_MASK); - if (rsrc & VGA_RSRC_LEGACY_IO) - vgadev->io_lock_cnt++; - if (rsrc & VGA_RSRC_LEGACY_MEM) - vgadev->mem_lock_cnt++; - if (rsrc & VGA_RSRC_NORMAL_IO) - vgadev->io_norm_cnt++; - if (rsrc & VGA_RSRC_NORMAL_MEM) - vgadev->mem_norm_cnt++; - - return NULL; -} - -static void __vga_put(struct vga_device *vgadev, unsigned int rsrc) -{ - struct device *dev = &vgadev->pdev->dev; - unsigned int old_locks = vgadev->locks; - - vgaarb_dbg(dev, "%s\n", __func__); - - /* Update our counters, and account for equivalent legacy resources - * if we decode them - */ - if ((rsrc & VGA_RSRC_NORMAL_IO) && vgadev->io_norm_cnt > 0) { - vgadev->io_norm_cnt--; - if (vgadev->decodes & VGA_RSRC_LEGACY_IO) - rsrc |= VGA_RSRC_LEGACY_IO; - } - if ((rsrc & VGA_RSRC_NORMAL_MEM) && vgadev->mem_norm_cnt > 0) { - vgadev->mem_norm_cnt--; - if (vgadev->decodes & VGA_RSRC_LEGACY_MEM) - rsrc |= VGA_RSRC_LEGACY_MEM; - } - if ((rsrc & VGA_RSRC_LEGACY_IO) && vgadev->io_lock_cnt > 0) - vgadev->io_lock_cnt--; - if ((rsrc & VGA_RSRC_LEGACY_MEM) && vgadev->mem_lock_cnt > 0) - vgadev->mem_lock_cnt--; - - /* Just clear lock bits, we do lazy operations so we don't really - * have to bother about anything else at this point - */ - if (vgadev->io_lock_cnt == 0) - vgadev->locks &= ~VGA_RSRC_LEGACY_IO; - if (vgadev->mem_lock_cnt == 0) - vgadev->locks &= ~VGA_RSRC_LEGACY_MEM; - - /* Kick the wait queue in case somebody was waiting if we actually - * released something - */ - if (old_locks != vgadev->locks) - wake_up_all(&vga_wait_queue); -} - -/** - * vga_get - acquire & locks VGA resources - * @pdev: pci device of the VGA card or NULL for the system default - * @rsrc: bit mask of resources to acquire and lock - * @interruptible: blocking should be interruptible by signals ? - * - * This function acquires VGA resources for the given card and mark those - * resources locked. If the resource requested are "normal" (and not legacy) - * resources, the arbiter will first check whether the card is doing legacy - * decoding for that type of resource. If yes, the lock is "converted" into a - * legacy resource lock. - * - * The arbiter will first look for all VGA cards that might conflict and disable - * their IOs and/or Memory access, including VGA forwarding on P2P bridges if - * necessary, so that the requested resources can be used. Then, the card is - * marked as locking these resources and the IO and/or Memory accesses are - * enabled on the card (including VGA forwarding on parent P2P bridges if any). - * - * This function will block if some conflicting card is already locking one of - * the required resources (or any resource on a different bus segment, since P2P - * bridges don't differentiate VGA memory and IO afaik). You can indicate - * whether this blocking should be interruptible by a signal (for userland - * interface) or not. - * - * Must not be called at interrupt time or in atomic context. If the card - * already owns the resources, the function succeeds. Nested calls are - * supported (a per-resource counter is maintained) - * - * On success, release the VGA resource again with vga_put(). - * - * Returns: - * - * 0 on success, negative error code on failure. - */ -int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible) -{ - struct vga_device *vgadev, *conflict; - unsigned long flags; - wait_queue_entry_t wait; - int rc = 0; - - vga_check_first_use(); - /* The one who calls us should check for this, but lets be sure... */ - if (pdev == NULL) - pdev = vga_default_device(); - if (pdev == NULL) - return 0; - - for (;;) { - spin_lock_irqsave(&vga_lock, flags); - vgadev = vgadev_find(pdev); - if (vgadev == NULL) { - spin_unlock_irqrestore(&vga_lock, flags); - rc = -ENODEV; - break; - } - conflict = __vga_tryget(vgadev, rsrc); - spin_unlock_irqrestore(&vga_lock, flags); - if (conflict == NULL) - break; - - - /* We have a conflict, we wait until somebody kicks the - * work queue. Currently we have one work queue that we - * kick each time some resources are released, but it would - * be fairly easy to have a per device one so that we only - * need to attach to the conflicting device - */ - init_waitqueue_entry(&wait, current); - add_wait_queue(&vga_wait_queue, &wait); - set_current_state(interruptible ? - TASK_INTERRUPTIBLE : - TASK_UNINTERRUPTIBLE); - if (interruptible && signal_pending(current)) { - __set_current_state(TASK_RUNNING); - remove_wait_queue(&vga_wait_queue, &wait); - rc = -ERESTARTSYS; - break; - } - schedule(); - remove_wait_queue(&vga_wait_queue, &wait); - } - return rc; -} -EXPORT_SYMBOL(vga_get); - -/** - * vga_tryget - try to acquire & lock legacy VGA resources - * @pdev: pci devivce of VGA card or NULL for system default - * @rsrc: bit mask of resources to acquire and lock - * - * This function performs the same operation as vga_get(), but will return an - * error (-EBUSY) instead of blocking if the resources are already locked by - * another card. It can be called in any context - * - * On success, release the VGA resource again with vga_put(). - * - * Returns: - * - * 0 on success, negative error code on failure. - */ -static int vga_tryget(struct pci_dev *pdev, unsigned int rsrc) -{ - struct vga_device *vgadev; - unsigned long flags; - int rc = 0; - - vga_check_first_use(); - - /* The one who calls us should check for this, but lets be sure... */ - if (pdev == NULL) - pdev = vga_default_device(); - if (pdev == NULL) - return 0; - spin_lock_irqsave(&vga_lock, flags); - vgadev = vgadev_find(pdev); - if (vgadev == NULL) { - rc = -ENODEV; - goto bail; - } - if (__vga_tryget(vgadev, rsrc)) - rc = -EBUSY; -bail: - spin_unlock_irqrestore(&vga_lock, flags); - return rc; -} - -/** - * vga_put - release lock on legacy VGA resources - * @pdev: pci device of VGA card or NULL for system default - * @rsrc: but mask of resource to release - * - * This fuction releases resources previously locked by vga_get() or - * vga_tryget(). The resources aren't disabled right away, so that a subsequence - * vga_get() on the same card will succeed immediately. Resources have a - * counter, so locks are only released if the counter reaches 0. - */ -void vga_put(struct pci_dev *pdev, unsigned int rsrc) -{ - struct vga_device *vgadev; - unsigned long flags; - - /* The one who calls us should check for this, but lets be sure... */ - if (pdev == NULL) - pdev = vga_default_device(); - if (pdev == NULL) - return; - spin_lock_irqsave(&vga_lock, flags); - vgadev = vgadev_find(pdev); - if (vgadev == NULL) - goto bail; - __vga_put(vgadev, rsrc); -bail: - spin_unlock_irqrestore(&vga_lock, flags); -} -EXPORT_SYMBOL(vga_put); - -/* - * Rules for using a bridge to control a VGA descendant decoding: if a bridge - * has only one VGA descendant then it can be used to control the VGA routing - * for that device. It should always use the bridge closest to the device to - * control it. If a bridge has a direct VGA descendant, but also have a sub- - * bridge VGA descendant then we cannot use that bridge to control the direct - * VGA descendant. So for every device we register, we need to iterate all - * its parent bridges so we can invalidate any devices using them properly. - */ -static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev) -{ - struct vga_device *same_bridge_vgadev; - struct pci_bus *new_bus, *bus; - struct pci_dev *new_bridge, *bridge; - - vgadev->bridge_has_one_vga = true; - - if (list_empty(&vga_list)) - return; - - /* okay iterate the new devices bridge hierarachy */ - new_bus = vgadev->pdev->bus; - while (new_bus) { - new_bridge = new_bus->self; - - /* go through list of devices already registered */ - list_for_each_entry(same_bridge_vgadev, &vga_list, list) { - bus = same_bridge_vgadev->pdev->bus; - bridge = bus->self; - - /* see if the share a bridge with this device */ - if (new_bridge == bridge) { - /* - * If their direct parent bridge is the same - * as any bridge of this device then it can't - * be used for that device. - */ - same_bridge_vgadev->bridge_has_one_vga = false; - } - - /* - * Now iterate the previous devices bridge hierarchy. - * If the new devices parent bridge is in the other - * devices hierarchy then we can't use it to control - * this device - */ - while (bus) { - bridge = bus->self; - - if (bridge && bridge == vgadev->pdev->bus->self) - vgadev->bridge_has_one_vga = false; - - bus = bus->parent; - } - } - new_bus = new_bus->parent; - } -} - -/* - * Currently, we assume that the "initial" setup of the system is - * not sane, that is we come up with conflicting devices and let - * the arbiter's client decides if devices decodes or not legacy - * things. - */ -static bool vga_arbiter_add_pci_device(struct pci_dev *pdev) -{ - struct vga_device *vgadev; - unsigned long flags; - struct pci_bus *bus; - struct pci_dev *bridge; - u16 cmd; - - /* Only deal with VGA class devices */ - if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA) - return false; - - /* Allocate structure */ - vgadev = kzalloc(sizeof(struct vga_device), GFP_KERNEL); - if (vgadev == NULL) { - vgaarb_err(&pdev->dev, "failed to allocate VGA arbiter data\n"); - /* - * What to do on allocation failure ? For now, let's just do - * nothing, I'm not sure there is anything saner to be done. - */ - return false; - } - - /* Take lock & check for duplicates */ - spin_lock_irqsave(&vga_lock, flags); - if (vgadev_find(pdev) != NULL) { - BUG_ON(1); - goto fail; - } - vgadev->pdev = pdev; - - /* By default, assume we decode everything */ - vgadev->decodes = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM | - VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM; - - /* by default mark it as decoding */ - vga_decode_count++; - /* Mark that we "own" resources based on our enables, we will - * clear that below if the bridge isn't forwarding - */ - pci_read_config_word(pdev, PCI_COMMAND, &cmd); - if (cmd & PCI_COMMAND_IO) - vgadev->owns |= VGA_RSRC_LEGACY_IO; - if (cmd & PCI_COMMAND_MEMORY) - vgadev->owns |= VGA_RSRC_LEGACY_MEM; - - /* Check if VGA cycles can get down to us */ - bus = pdev->bus; - while (bus) { - bridge = bus->self; - if (bridge) { - u16 l; - - pci_read_config_word(bridge, PCI_BRIDGE_CONTROL, &l); - if (!(l & PCI_BRIDGE_CTL_VGA)) { - vgadev->owns = 0; - break; - } - } - bus = bus->parent; - } - - /* Deal with VGA default device. Use first enabled one - * by default if arch doesn't have it's own hook - */ - if (vga_default == NULL && - ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) { - vgaarb_info(&pdev->dev, "setting as boot VGA device\n"); - vga_set_default_device(pdev); - } - - vga_arbiter_check_bridge_sharing(vgadev); - - /* Add to the list */ - list_add_tail(&vgadev->list, &vga_list); - vga_count++; - vgaarb_info(&pdev->dev, "VGA device added: decodes=%s,owns=%s,locks=%s\n", - vga_iostate_to_str(vgadev->decodes), - vga_iostate_to_str(vgadev->owns), - vga_iostate_to_str(vgadev->locks)); - - spin_unlock_irqrestore(&vga_lock, flags); - return true; -fail: - spin_unlock_irqrestore(&vga_lock, flags); - kfree(vgadev); - return false; -} - -static bool vga_arbiter_del_pci_device(struct pci_dev *pdev) -{ - struct vga_device *vgadev; - unsigned long flags; - bool ret = true; - - spin_lock_irqsave(&vga_lock, flags); - vgadev = vgadev_find(pdev); - if (vgadev == NULL) { - ret = false; - goto bail; - } - - if (vga_default == pdev) - vga_set_default_device(NULL); - - if (vgadev->decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM)) - vga_decode_count--; - - /* Remove entry from list */ - list_del(&vgadev->list); - vga_count--; - /* Notify userland driver that the device is gone so it discards - * it's copies of the pci_dev pointer - */ - vga_arb_device_card_gone(pdev); - - /* Wake up all possible waiters */ - wake_up_all(&vga_wait_queue); -bail: - spin_unlock_irqrestore(&vga_lock, flags); - kfree(vgadev); - return ret; -} - -/* this is called with the lock */ -static inline void vga_update_device_decodes(struct vga_device *vgadev, - int new_decodes) -{ - struct device *dev = &vgadev->pdev->dev; - int old_decodes, decodes_removed, decodes_unlocked; - - old_decodes = vgadev->decodes; - decodes_removed = ~new_decodes & old_decodes; - decodes_unlocked = vgadev->locks & decodes_removed; - vgadev->decodes = new_decodes; - - vgaarb_info(dev, "changed VGA decodes: olddecodes=%s,decodes=%s:owns=%s\n", - vga_iostate_to_str(old_decodes), - vga_iostate_to_str(vgadev->decodes), - vga_iostate_to_str(vgadev->owns)); - - /* if we removed locked decodes, lock count goes to zero, and release */ - if (decodes_unlocked) { - if (decodes_unlocked & VGA_RSRC_LEGACY_IO) - vgadev->io_lock_cnt = 0; - if (decodes_unlocked & VGA_RSRC_LEGACY_MEM) - vgadev->mem_lock_cnt = 0; - __vga_put(vgadev, decodes_unlocked); - } - - /* change decodes counter */ - if (old_decodes & VGA_RSRC_LEGACY_MASK && - !(new_decodes & VGA_RSRC_LEGACY_MASK)) - vga_decode_count--; - if (!(old_decodes & VGA_RSRC_LEGACY_MASK) && - new_decodes & VGA_RSRC_LEGACY_MASK) - vga_decode_count++; - vgaarb_dbg(dev, "decoding count now is: %d\n", vga_decode_count); -} - -static void __vga_set_legacy_decoding(struct pci_dev *pdev, - unsigned int decodes, - bool userspace) -{ - struct vga_device *vgadev; - unsigned long flags; - - decodes &= VGA_RSRC_LEGACY_MASK; - - spin_lock_irqsave(&vga_lock, flags); - vgadev = vgadev_find(pdev); - if (vgadev == NULL) - goto bail; - - /* don't let userspace futz with kernel driver decodes */ - if (userspace && vgadev->set_decode) - goto bail; - - /* update the device decodes + counter */ - vga_update_device_decodes(vgadev, decodes); - - /* XXX if somebody is going from "doesn't decode" to "decodes" state - * here, additional care must be taken as we may have pending owner - * ship of non-legacy region ... - */ -bail: - spin_unlock_irqrestore(&vga_lock, flags); -} - -/** - * vga_set_legacy_decoding - * @pdev: pci device of the VGA card - * @decodes: bit mask of what legacy regions the card decodes - * - * Indicates to the arbiter if the card decodes legacy VGA IOs, legacy VGA - * Memory, both, or none. All cards default to both, the card driver (fbdev for - * example) should tell the arbiter if it has disabled legacy decoding, so the - * card can be left out of the arbitration process (and can be safe to take - * interrupts at any time. - */ -void vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes) -{ - __vga_set_legacy_decoding(pdev, decodes, false); -} -EXPORT_SYMBOL(vga_set_legacy_decoding); - -/** - * vga_client_register - register or unregister a VGA arbitration client - * @pdev: pci device of the VGA client - * @set_decode: vga decode change callback - * - * Clients have two callback mechanisms they can use. - * - * @set_decode callback: If a client can disable its GPU VGA resource, it - * will get a callback from this to set the encode/decode state. - * - * Rationale: we cannot disable VGA decode resources unconditionally some single - * GPU laptops seem to require ACPI or BIOS access to the VGA registers to - * control things like backlights etc. Hopefully newer multi-GPU laptops do - * something saner, and desktops won't have any special ACPI for this. The - * driver will get a callback when VGA arbitration is first used by userspace - * since some older X servers have issues. - * - * This function does not check whether a client for @pdev has been registered - * already. - * - * To unregister just call vga_client_unregister(). - * - * Returns: 0 on success, -1 on failure - */ -int vga_client_register(struct pci_dev *pdev, - unsigned int (*set_decode)(struct pci_dev *pdev, bool decode)) -{ - int ret = -ENODEV; - struct vga_device *vgadev; - unsigned long flags; - - spin_lock_irqsave(&vga_lock, flags); - vgadev = vgadev_find(pdev); - if (!vgadev) - goto bail; - - vgadev->set_decode = set_decode; - ret = 0; - -bail: - spin_unlock_irqrestore(&vga_lock, flags); - return ret; - -} -EXPORT_SYMBOL(vga_client_register); - -/* - * Char driver implementation - * - * Semantics is: - * - * open : open user instance of the arbitrer. by default, it's - * attached to the default VGA device of the system. - * - * close : close user instance, release locks - * - * read : return a string indicating the status of the target. - * an IO state string is of the form {io,mem,io+mem,none}, - * mc and ic are respectively mem and io lock counts (for - * debugging/diagnostic only). "decodes" indicate what the - * card currently decodes, "owns" indicates what is currently - * enabled on it, and "locks" indicates what is locked by this - * card. If the card is unplugged, we get "invalid" then for - * card_ID and an -ENODEV error is returned for any command - * until a new card is targeted - * - * ",decodes=,owns=,locks= (ic,mc)" - * - * write : write a command to the arbiter. List of commands is: - * - * target : switch target to card (see below) - * lock : acquires locks on target ("none" is invalid io_state) - * trylock : non-blocking acquire locks on target - * unlock : release locks on target - * unlock all : release all locks on target held by this user - * decodes : set the legacy decoding attributes for the card - * - * poll : event if something change on any card (not just the target) - * - * card_ID is of the form "PCI:domain:bus:dev.fn". It can be set to "default" - * to go back to the system default card (TODO: not implemented yet). - * Currently, only PCI is supported as a prefix, but the userland API may - * support other bus types in the future, even if the current kernel - * implementation doesn't. - * - * Note about locks: - * - * The driver keeps track of which user has what locks on which card. It - * supports stacking, like the kernel one. This complexifies the implementation - * a bit, but makes the arbiter more tolerant to userspace problems and able - * to properly cleanup in all cases when a process dies. - * Currently, a max of 16 cards simultaneously can have locks issued from - * userspace for a given user (file descriptor instance) of the arbiter. - * - * If the device is hot-unplugged, there is a hook inside the module to notify - * they being added/removed in the system and automatically added/removed in - * the arbiter. - */ - -#define MAX_USER_CARDS CONFIG_VGA_ARB_MAX_GPUS -#define PCI_INVALID_CARD ((struct pci_dev *)-1UL) - -/* - * Each user has an array of these, tracking which cards have locks - */ -struct vga_arb_user_card { - struct pci_dev *pdev; - unsigned int mem_cnt; - unsigned int io_cnt; -}; - -struct vga_arb_private { - struct list_head list; - struct pci_dev *target; - struct vga_arb_user_card cards[MAX_USER_CARDS]; - spinlock_t lock; -}; - -static LIST_HEAD(vga_user_list); -static DEFINE_SPINLOCK(vga_user_lock); - - -/* - * This function gets a string in the format: "PCI:domain:bus:dev.fn" and - * returns the respective values. If the string is not in this format, - * it returns 0. - */ -static int vga_pci_str_to_vars(char *buf, int count, unsigned int *domain, - unsigned int *bus, unsigned int *devfn) -{ - int n; - unsigned int slot, func; - - - n = sscanf(buf, "PCI:%x:%x:%x.%x", domain, bus, &slot, &func); - if (n != 4) - return 0; - - *devfn = PCI_DEVFN(slot, func); - - return 1; -} - -static ssize_t vga_arb_read(struct file *file, char __user *buf, - size_t count, loff_t *ppos) -{ - struct vga_arb_private *priv = file->private_data; - struct vga_device *vgadev; - struct pci_dev *pdev; - unsigned long flags; - size_t len; - int rc; - char *lbuf; - - lbuf = kmalloc(1024, GFP_KERNEL); - if (lbuf == NULL) - return -ENOMEM; - - /* Shields against vga_arb_device_card_gone (pci_dev going - * away), and allows access to vga list - */ - spin_lock_irqsave(&vga_lock, flags); - - /* If we are targeting the default, use it */ - pdev = priv->target; - if (pdev == NULL || pdev == PCI_INVALID_CARD) { - spin_unlock_irqrestore(&vga_lock, flags); - len = sprintf(lbuf, "invalid"); - goto done; - } - - /* Find card vgadev structure */ - vgadev = vgadev_find(pdev); - if (vgadev == NULL) { - /* Wow, it's not in the list, that shouldn't happen, - * let's fix us up and return invalid card - */ - if (pdev == priv->target) - vga_arb_device_card_gone(pdev); - spin_unlock_irqrestore(&vga_lock, flags); - len = sprintf(lbuf, "invalid"); - goto done; - } - - /* Fill the buffer with infos */ - len = snprintf(lbuf, 1024, - "count:%d,PCI:%s,decodes=%s,owns=%s,locks=%s(%d:%d)\n", - vga_decode_count, pci_name(pdev), - vga_iostate_to_str(vgadev->decodes), - vga_iostate_to_str(vgadev->owns), - vga_iostate_to_str(vgadev->locks), - vgadev->io_lock_cnt, vgadev->mem_lock_cnt); - - spin_unlock_irqrestore(&vga_lock, flags); -done: - - /* Copy that to user */ - if (len > count) - len = count; - rc = copy_to_user(buf, lbuf, len); - kfree(lbuf); - if (rc) - return -EFAULT; - return len; -} - -/* - * TODO: To avoid parsing inside kernel and to improve the speed we may - * consider use ioctl here - */ -static ssize_t vga_arb_write(struct file *file, const char __user *buf, - size_t count, loff_t *ppos) -{ - struct vga_arb_private *priv = file->private_data; - struct vga_arb_user_card *uc = NULL; - struct pci_dev *pdev; - - unsigned int io_state; - - char kbuf[64], *curr_pos; - size_t remaining = count; - - int ret_val; - int i; - - if (count >= sizeof(kbuf)) - return -EINVAL; - if (copy_from_user(kbuf, buf, count)) - return -EFAULT; - curr_pos = kbuf; - kbuf[count] = '\0'; /* Just to make sure... */ - - if (strncmp(curr_pos, "lock ", 5) == 0) { - curr_pos += 5; - remaining -= 5; - - pr_debug("client 0x%p called 'lock'\n", priv); - - if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { - ret_val = -EPROTO; - goto done; - } - if (io_state == VGA_RSRC_NONE) { - ret_val = -EPROTO; - goto done; - } - - pdev = priv->target; - if (priv->target == NULL) { - ret_val = -ENODEV; - goto done; - } - - vga_get_uninterruptible(pdev, io_state); - - /* Update the client's locks lists... */ - for (i = 0; i < MAX_USER_CARDS; i++) { - if (priv->cards[i].pdev == pdev) { - if (io_state & VGA_RSRC_LEGACY_IO) - priv->cards[i].io_cnt++; - if (io_state & VGA_RSRC_LEGACY_MEM) - priv->cards[i].mem_cnt++; - break; - } - } - - ret_val = count; - goto done; - } else if (strncmp(curr_pos, "unlock ", 7) == 0) { - curr_pos += 7; - remaining -= 7; - - pr_debug("client 0x%p called 'unlock'\n", priv); - - if (strncmp(curr_pos, "all", 3) == 0) - io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; - else { - if (!vga_str_to_iostate - (curr_pos, remaining, &io_state)) { - ret_val = -EPROTO; - goto done; - } - /* TODO: Add this? - if (io_state == VGA_RSRC_NONE) { - ret_val = -EPROTO; - goto done; - } - */ - } - - pdev = priv->target; - if (priv->target == NULL) { - ret_val = -ENODEV; - goto done; - } - for (i = 0; i < MAX_USER_CARDS; i++) { - if (priv->cards[i].pdev == pdev) - uc = &priv->cards[i]; - } - - if (!uc) { - ret_val = -EINVAL; - goto done; - } - - if (io_state & VGA_RSRC_LEGACY_IO && uc->io_cnt == 0) { - ret_val = -EINVAL; - goto done; - } - - if (io_state & VGA_RSRC_LEGACY_MEM && uc->mem_cnt == 0) { - ret_val = -EINVAL; - goto done; - } - - vga_put(pdev, io_state); - - if (io_state & VGA_RSRC_LEGACY_IO) - uc->io_cnt--; - if (io_state & VGA_RSRC_LEGACY_MEM) - uc->mem_cnt--; - - ret_val = count; - goto done; - } else if (strncmp(curr_pos, "trylock ", 8) == 0) { - curr_pos += 8; - remaining -= 8; - - pr_debug("client 0x%p called 'trylock'\n", priv); - - if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { - ret_val = -EPROTO; - goto done; - } - /* TODO: Add this? - if (io_state == VGA_RSRC_NONE) { - ret_val = -EPROTO; - goto done; - } - */ - - pdev = priv->target; - if (priv->target == NULL) { - ret_val = -ENODEV; - goto done; - } - - if (vga_tryget(pdev, io_state)) { - /* Update the client's locks lists... */ - for (i = 0; i < MAX_USER_CARDS; i++) { - if (priv->cards[i].pdev == pdev) { - if (io_state & VGA_RSRC_LEGACY_IO) - priv->cards[i].io_cnt++; - if (io_state & VGA_RSRC_LEGACY_MEM) - priv->cards[i].mem_cnt++; - break; - } - } - ret_val = count; - goto done; - } else { - ret_val = -EBUSY; - goto done; - } - - } else if (strncmp(curr_pos, "target ", 7) == 0) { - unsigned int domain, bus, devfn; - struct vga_device *vgadev; - - curr_pos += 7; - remaining -= 7; - pr_debug("client 0x%p called 'target'\n", priv); - /* if target is default */ - if (!strncmp(curr_pos, "default", 7)) - pdev = pci_dev_get(vga_default_device()); - else { - if (!vga_pci_str_to_vars(curr_pos, remaining, - &domain, &bus, &devfn)) { - ret_val = -EPROTO; - goto done; - } - pdev = pci_get_domain_bus_and_slot(domain, bus, devfn); - if (!pdev) { - pr_debug("invalid PCI address %04x:%02x:%02x.%x\n", - domain, bus, PCI_SLOT(devfn), - PCI_FUNC(devfn)); - ret_val = -ENODEV; - goto done; - } - - pr_debug("%s ==> %04x:%02x:%02x.%x pdev %p\n", curr_pos, - domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn), - pdev); - } - - vgadev = vgadev_find(pdev); - pr_debug("vgadev %p\n", vgadev); - if (vgadev == NULL) { - if (pdev) { - vgaarb_dbg(&pdev->dev, "not a VGA device\n"); - pci_dev_put(pdev); - } - - ret_val = -ENODEV; - goto done; - } - - priv->target = pdev; - for (i = 0; i < MAX_USER_CARDS; i++) { - if (priv->cards[i].pdev == pdev) - break; - if (priv->cards[i].pdev == NULL) { - priv->cards[i].pdev = pdev; - priv->cards[i].io_cnt = 0; - priv->cards[i].mem_cnt = 0; - break; - } - } - if (i == MAX_USER_CARDS) { - vgaarb_dbg(&pdev->dev, "maximum user cards (%d) number reached, ignoring this one!\n", - MAX_USER_CARDS); - pci_dev_put(pdev); - /* XXX: which value to return? */ - ret_val = -ENOMEM; - goto done; - } - - ret_val = count; - pci_dev_put(pdev); - goto done; - - - } else if (strncmp(curr_pos, "decodes ", 8) == 0) { - curr_pos += 8; - remaining -= 8; - pr_debug("client 0x%p called 'decodes'\n", priv); - - if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { - ret_val = -EPROTO; - goto done; - } - pdev = priv->target; - if (priv->target == NULL) { - ret_val = -ENODEV; - goto done; - } - - __vga_set_legacy_decoding(pdev, io_state, true); - ret_val = count; - goto done; - } - /* If we got here, the message written is not part of the protocol! */ - return -EPROTO; - -done: - return ret_val; -} - -static __poll_t vga_arb_fpoll(struct file *file, poll_table *wait) -{ - pr_debug("%s\n", __func__); - - poll_wait(file, &vga_wait_queue, wait); - return EPOLLIN; -} - -static int vga_arb_open(struct inode *inode, struct file *file) -{ - struct vga_arb_private *priv; - unsigned long flags; - - pr_debug("%s\n", __func__); - - priv = kzalloc(sizeof(*priv), GFP_KERNEL); - if (priv == NULL) - return -ENOMEM; - spin_lock_init(&priv->lock); - file->private_data = priv; - - spin_lock_irqsave(&vga_user_lock, flags); - list_add(&priv->list, &vga_user_list); - spin_unlock_irqrestore(&vga_user_lock, flags); - - /* Set the client' lists of locks */ - priv->target = vga_default_device(); /* Maybe this is still null! */ - priv->cards[0].pdev = priv->target; - priv->cards[0].io_cnt = 0; - priv->cards[0].mem_cnt = 0; - - - return 0; -} - -static int vga_arb_release(struct inode *inode, struct file *file) -{ - struct vga_arb_private *priv = file->private_data; - struct vga_arb_user_card *uc; - unsigned long flags; - int i; - - pr_debug("%s\n", __func__); - - spin_lock_irqsave(&vga_user_lock, flags); - list_del(&priv->list); - for (i = 0; i < MAX_USER_CARDS; i++) { - uc = &priv->cards[i]; - if (uc->pdev == NULL) - continue; - vgaarb_dbg(&uc->pdev->dev, "uc->io_cnt == %d, uc->mem_cnt == %d\n", - uc->io_cnt, uc->mem_cnt); - while (uc->io_cnt--) - vga_put(uc->pdev, VGA_RSRC_LEGACY_IO); - while (uc->mem_cnt--) - vga_put(uc->pdev, VGA_RSRC_LEGACY_MEM); - } - spin_unlock_irqrestore(&vga_user_lock, flags); - - kfree(priv); - - return 0; -} - -static void vga_arb_device_card_gone(struct pci_dev *pdev) -{ -} - -/* - * callback any registered clients to let them know we have a - * change in VGA cards - */ -static void vga_arbiter_notify_clients(void) -{ - struct vga_device *vgadev; - unsigned long flags; - uint32_t new_decodes; - bool new_state; - - if (!vga_arbiter_used) - return; - - spin_lock_irqsave(&vga_lock, flags); - list_for_each_entry(vgadev, &vga_list, list) { - if (vga_count > 1) - new_state = false; - else - new_state = true; - if (vgadev->set_decode) { - new_decodes = vgadev->set_decode(vgadev->pdev, - new_state); - vga_update_device_decodes(vgadev, new_decodes); - } - } - spin_unlock_irqrestore(&vga_lock, flags); -} - -static int pci_notify(struct notifier_block *nb, unsigned long action, - void *data) -{ - struct device *dev = data; - struct pci_dev *pdev = to_pci_dev(dev); - bool notify = false; - - vgaarb_dbg(dev, "%s\n", __func__); - - /* For now we're only intereted in devices added and removed. I didn't - * test this thing here, so someone needs to double check for the - * cases of hotplugable vga cards. */ - if (action == BUS_NOTIFY_ADD_DEVICE) - notify = vga_arbiter_add_pci_device(pdev); - else if (action == BUS_NOTIFY_DEL_DEVICE) - notify = vga_arbiter_del_pci_device(pdev); - - if (notify) - vga_arbiter_notify_clients(); - return 0; -} - -static struct notifier_block pci_notifier = { - .notifier_call = pci_notify, -}; - -static const struct file_operations vga_arb_device_fops = { - .read = vga_arb_read, - .write = vga_arb_write, - .poll = vga_arb_fpoll, - .open = vga_arb_open, - .release = vga_arb_release, - .llseek = noop_llseek, -}; - -static struct miscdevice vga_arb_device = { - MISC_DYNAMIC_MINOR, "vga_arbiter", &vga_arb_device_fops -}; - -#if defined(CONFIG_ACPI) -static bool vga_arb_integrated_gpu(struct device *dev) -{ - struct acpi_device *adev = ACPI_COMPANION(dev); - - return adev && !strcmp(acpi_device_hid(adev), ACPI_VIDEO_HID); -} -#else -static bool vga_arb_integrated_gpu(struct device *dev) -{ - return false; -} -#endif - -static void __init vga_arb_select_default_device(void) -{ - struct pci_dev *pdev, *found = NULL; - struct vga_device *vgadev; - -#if defined(CONFIG_X86) || defined(CONFIG_IA64) - u64 base = screen_info.lfb_base; - u64 size = screen_info.lfb_size; - u64 limit; - resource_size_t start, end; - unsigned long flags; - int i; - - if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) - base |= (u64)screen_info.ext_lfb_base << 32; - - limit = base + size; - - list_for_each_entry(vgadev, &vga_list, list) { - struct device *dev = &vgadev->pdev->dev; - /* - * Override vga_arbiter_add_pci_device()'s I/O based detection - * as it may take the wrong device (e.g. on Apple system under - * EFI). - * - * Select the device owning the boot framebuffer if there is - * one. - */ - - /* Does firmware framebuffer belong to us? */ - for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) { - flags = pci_resource_flags(vgadev->pdev, i); - - if ((flags & IORESOURCE_MEM) == 0) - continue; - - start = pci_resource_start(vgadev->pdev, i); - end = pci_resource_end(vgadev->pdev, i); - - if (!start || !end) - continue; - - if (base < start || limit >= end) - continue; - - if (!vga_default_device()) - vgaarb_info(dev, "setting as boot device\n"); - else if (vgadev->pdev != vga_default_device()) - vgaarb_info(dev, "overriding boot device\n"); - vga_set_default_device(vgadev->pdev); - } - } -#endif - - if (!vga_default_device()) { - list_for_each_entry_reverse(vgadev, &vga_list, list) { - struct device *dev = &vgadev->pdev->dev; - u16 cmd; - - pdev = vgadev->pdev; - pci_read_config_word(pdev, PCI_COMMAND, &cmd); - if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) { - found = pdev; - if (vga_arb_integrated_gpu(dev)) - break; - } - } - } - - if (found) { - vgaarb_info(&found->dev, "setting as boot device (VGA legacy resources not available)\n"); - vga_set_default_device(found); - return; - } - - if (!vga_default_device()) { - vgadev = list_first_entry_or_null(&vga_list, - struct vga_device, list); - if (vgadev) { - struct device *dev = &vgadev->pdev->dev; - vgaarb_info(dev, "setting as boot device (VGA legacy resources not available)\n"); - vga_set_default_device(vgadev->pdev); - } - } -} - -static int __init vga_arb_device_init(void) -{ - int rc; - struct pci_dev *pdev; - struct vga_device *vgadev; - - rc = misc_register(&vga_arb_device); - if (rc < 0) - pr_err("error %d registering device\n", rc); - - bus_register_notifier(&pci_bus_type, &pci_notifier); - - /* We add all PCI devices satisfying VGA class in the arbiter by - * default */ - pdev = NULL; - while ((pdev = - pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, - PCI_ANY_ID, pdev)) != NULL) - vga_arbiter_add_pci_device(pdev); - - list_for_each_entry(vgadev, &vga_list, list) { - struct device *dev = &vgadev->pdev->dev; - - if (vgadev->bridge_has_one_vga) - vgaarb_info(dev, "bridge control possible\n"); - else - vgaarb_info(dev, "no bridge control possible\n"); - } - - vga_arb_select_default_device(); - - pr_info("loaded\n"); - return rc; -} -subsys_initcall(vga_arb_device_init); diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig index d98fafdd0f99..133c73207782 100644 --- a/drivers/pci/Kconfig +++ b/drivers/pci/Kconfig @@ -252,6 +252,25 @@ config PCIE_BUS_PEER2PEER endchoice +config VGA_ARB + bool "VGA Arbitration" if EXPERT + default y + depends on (PCI && !S390) + help + Some "legacy" VGA devices implemented on PCI typically have the same + hard-decoded addresses as they did on ISA. When multiple PCI devices + are accessed at same time they need some kind of coordination. Please + see Documentation/gpu/vgaarbiter.rst for more details. Select this to + enable VGA arbiter. + +config VGA_ARB_MAX_GPUS + int "Maximum number of GPUs" + default 16 + depends on VGA_ARB + help + Reserves space in the kernel to maintain resource locking for + multiple GPUS. The overhead for each GPU is very small. + source "drivers/pci/hotplug/Kconfig" source "drivers/pci/controller/Kconfig" source "drivers/pci/endpoint/Kconfig" diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile index 37be95adf169..0da6b1ebc694 100644 --- a/drivers/pci/Makefile +++ b/drivers/pci/Makefile @@ -30,6 +30,7 @@ obj-$(CONFIG_PCI_PF_STUB) += pci-pf-stub.o obj-$(CONFIG_PCI_ECAM) += ecam.o obj-$(CONFIG_PCI_P2PDMA) += p2pdma.o obj-$(CONFIG_XEN_PCIDEV_FRONTEND) += xen-pcifront.o +obj-$(CONFIG_VGA_ARB) += vgaarb.o # Endpoint library must be initialized before its users obj-$(CONFIG_PCI_ENDPOINT) += endpoint/ diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c new file mode 100644 index 000000000000..8320385a487b --- /dev/null +++ b/drivers/pci/vgaarb.c @@ -0,0 +1,1567 @@ +/* + * vgaarb.c: Implements the VGA arbitration. For details refer to + * Documentation/gpu/vgaarbiter.rst + * + * + * (C) Copyright 2005 Benjamin Herrenschmidt + * (C) Copyright 2007 Paulo R. Zanoni + * (C) Copyright 2007, 2009 Tiago Vignatti + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + * DEALINGS + * IN THE SOFTWARE. + * + */ + +#define pr_fmt(fmt) "vgaarb: " fmt + +#define vgaarb_dbg(dev, fmt, arg...) dev_dbg(dev, "vgaarb: " fmt, ##arg) +#define vgaarb_info(dev, fmt, arg...) dev_info(dev, "vgaarb: " fmt, ##arg) +#define vgaarb_err(dev, fmt, arg...) dev_err(dev, "vgaarb: " fmt, ##arg) + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include + +static void vga_arbiter_notify_clients(void); +/* + * We keep a list of all vga devices in the system to speed + * up the various operations of the arbiter + */ +struct vga_device { + struct list_head list; + struct pci_dev *pdev; + unsigned int decodes; /* what does it decodes */ + unsigned int owns; /* what does it owns */ + unsigned int locks; /* what does it locks */ + unsigned int io_lock_cnt; /* legacy IO lock count */ + unsigned int mem_lock_cnt; /* legacy MEM lock count */ + unsigned int io_norm_cnt; /* normal IO count */ + unsigned int mem_norm_cnt; /* normal MEM count */ + bool bridge_has_one_vga; + unsigned int (*set_decode)(struct pci_dev *pdev, bool decode); +}; + +static LIST_HEAD(vga_list); +static int vga_count, vga_decode_count; +static bool vga_arbiter_used; +static DEFINE_SPINLOCK(vga_lock); +static DECLARE_WAIT_QUEUE_HEAD(vga_wait_queue); + + +static const char *vga_iostate_to_str(unsigned int iostate) +{ + /* Ignore VGA_RSRC_IO and VGA_RSRC_MEM */ + iostate &= VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; + switch (iostate) { + case VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM: + return "io+mem"; + case VGA_RSRC_LEGACY_IO: + return "io"; + case VGA_RSRC_LEGACY_MEM: + return "mem"; + } + return "none"; +} + +static int vga_str_to_iostate(char *buf, int str_size, int *io_state) +{ + /* we could in theory hand out locks on IO and mem + * separately to userspace but it can cause deadlocks */ + if (strncmp(buf, "none", 4) == 0) { + *io_state = VGA_RSRC_NONE; + return 1; + } + + /* XXX We're not chekcing the str_size! */ + if (strncmp(buf, "io+mem", 6) == 0) + goto both; + else if (strncmp(buf, "io", 2) == 0) + goto both; + else if (strncmp(buf, "mem", 3) == 0) + goto both; + return 0; +both: + *io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; + return 1; +} + +/* this is only used a cookie - it should not be dereferenced */ +static struct pci_dev *vga_default; + +static void vga_arb_device_card_gone(struct pci_dev *pdev); + +/* Find somebody in our list */ +static struct vga_device *vgadev_find(struct pci_dev *pdev) +{ + struct vga_device *vgadev; + + list_for_each_entry(vgadev, &vga_list, list) + if (pdev == vgadev->pdev) + return vgadev; + return NULL; +} + +/** + * vga_default_device - return the default VGA device, for vgacon + * + * This can be defined by the platform. The default implementation + * is rather dumb and will probably only work properly on single + * vga card setups and/or x86 platforms. + * + * If your VGA default device is not PCI, you'll have to return + * NULL here. In this case, I assume it will not conflict with + * any PCI card. If this is not true, I'll have to define two archs + * hooks for enabling/disabling the VGA default device if that is + * possible. This may be a problem with real _ISA_ VGA cards, in + * addition to a PCI one. I don't know at this point how to deal + * with that card. Can theirs IOs be disabled at all ? If not, then + * I suppose it's a matter of having the proper arch hook telling + * us about it, so we basically never allow anybody to succeed a + * vga_get()... + */ +struct pci_dev *vga_default_device(void) +{ + return vga_default; +} +EXPORT_SYMBOL_GPL(vga_default_device); + +void vga_set_default_device(struct pci_dev *pdev) +{ + if (vga_default == pdev) + return; + + pci_dev_put(vga_default); + vga_default = pci_dev_get(pdev); +} + +/** + * vga_remove_vgacon - deactivete vga console + * + * Unbind and unregister vgacon in case pdev is the default vga + * device. Can be called by gpu drivers on initialization to make + * sure vga register access done by vgacon will not disturb the + * device. + * + * @pdev: pci device. + */ +#if !defined(CONFIG_VGA_CONSOLE) +int vga_remove_vgacon(struct pci_dev *pdev) +{ + return 0; +} +#elif !defined(CONFIG_DUMMY_CONSOLE) +int vga_remove_vgacon(struct pci_dev *pdev) +{ + return -ENODEV; +} +#else +int vga_remove_vgacon(struct pci_dev *pdev) +{ + int ret = 0; + + if (pdev != vga_default) + return 0; + vgaarb_info(&pdev->dev, "deactivate vga console\n"); + + console_lock(); + if (con_is_bound(&vga_con)) + ret = do_take_over_console(&dummy_con, 0, + MAX_NR_CONSOLES - 1, 1); + if (ret == 0) { + ret = do_unregister_con_driver(&vga_con); + + /* Ignore "already unregistered". */ + if (ret == -ENODEV) + ret = 0; + } + console_unlock(); + + return ret; +} +#endif +EXPORT_SYMBOL(vga_remove_vgacon); + +/* If we don't ever use VGA arb we should avoid + turning off anything anywhere due to old X servers getting + confused about the boot device not being VGA */ +static void vga_check_first_use(void) +{ + /* we should inform all GPUs in the system that + * VGA arb has occurred and to try and disable resources + * if they can */ + if (!vga_arbiter_used) { + vga_arbiter_used = true; + vga_arbiter_notify_clients(); + } +} + +static struct vga_device *__vga_tryget(struct vga_device *vgadev, + unsigned int rsrc) +{ + struct device *dev = &vgadev->pdev->dev; + unsigned int wants, legacy_wants, match; + struct vga_device *conflict; + unsigned int pci_bits; + u32 flags = 0; + + /* Account for "normal" resources to lock. If we decode the legacy, + * counterpart, we need to request it as well + */ + if ((rsrc & VGA_RSRC_NORMAL_IO) && + (vgadev->decodes & VGA_RSRC_LEGACY_IO)) + rsrc |= VGA_RSRC_LEGACY_IO; + if ((rsrc & VGA_RSRC_NORMAL_MEM) && + (vgadev->decodes & VGA_RSRC_LEGACY_MEM)) + rsrc |= VGA_RSRC_LEGACY_MEM; + + vgaarb_dbg(dev, "%s: %d\n", __func__, rsrc); + vgaarb_dbg(dev, "%s: owns: %d\n", __func__, vgadev->owns); + + /* Check what resources we need to acquire */ + wants = rsrc & ~vgadev->owns; + + /* We already own everything, just mark locked & bye bye */ + if (wants == 0) + goto lock_them; + + /* We don't need to request a legacy resource, we just enable + * appropriate decoding and go + */ + legacy_wants = wants & VGA_RSRC_LEGACY_MASK; + if (legacy_wants == 0) + goto enable_them; + + /* Ok, we don't, let's find out how we need to kick off */ + list_for_each_entry(conflict, &vga_list, list) { + unsigned int lwants = legacy_wants; + unsigned int change_bridge = 0; + + /* Don't conflict with myself */ + if (vgadev == conflict) + continue; + + /* We have a possible conflict. before we go further, we must + * check if we sit on the same bus as the conflicting device. + * if we don't, then we must tie both IO and MEM resources + * together since there is only a single bit controlling + * VGA forwarding on P2P bridges + */ + if (vgadev->pdev->bus != conflict->pdev->bus) { + change_bridge = 1; + lwants = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; + } + + /* Check if the guy has a lock on the resource. If he does, + * return the conflicting entry + */ + if (conflict->locks & lwants) + return conflict; + + /* Ok, now check if it owns the resource we want. We can + * lock resources that are not decoded, therefore a device + * can own resources it doesn't decode. + */ + match = lwants & conflict->owns; + if (!match) + continue; + + /* looks like he doesn't have a lock, we can steal + * them from him + */ + + flags = 0; + pci_bits = 0; + + /* If we can't control legacy resources via the bridge, we + * also need to disable normal decoding. + */ + if (!conflict->bridge_has_one_vga) { + if ((match & conflict->decodes) & VGA_RSRC_LEGACY_MEM) + pci_bits |= PCI_COMMAND_MEMORY; + if ((match & conflict->decodes) & VGA_RSRC_LEGACY_IO) + pci_bits |= PCI_COMMAND_IO; + + if (pci_bits) + flags |= PCI_VGA_STATE_CHANGE_DECODES; + } + + if (change_bridge) + flags |= PCI_VGA_STATE_CHANGE_BRIDGE; + + pci_set_vga_state(conflict->pdev, false, pci_bits, flags); + conflict->owns &= ~match; + + /* If we disabled normal decoding, reflect it in owns */ + if (pci_bits & PCI_COMMAND_MEMORY) + conflict->owns &= ~VGA_RSRC_NORMAL_MEM; + if (pci_bits & PCI_COMMAND_IO) + conflict->owns &= ~VGA_RSRC_NORMAL_IO; + } + +enable_them: + /* ok dude, we got it, everybody conflicting has been disabled, let's + * enable us. Mark any bits in "owns" regardless of whether we + * decoded them. We can lock resources we don't decode, therefore + * we must track them via "owns". + */ + flags = 0; + pci_bits = 0; + + if (!vgadev->bridge_has_one_vga) { + flags |= PCI_VGA_STATE_CHANGE_DECODES; + if (wants & (VGA_RSRC_LEGACY_MEM|VGA_RSRC_NORMAL_MEM)) + pci_bits |= PCI_COMMAND_MEMORY; + if (wants & (VGA_RSRC_LEGACY_IO|VGA_RSRC_NORMAL_IO)) + pci_bits |= PCI_COMMAND_IO; + } + if (wants & VGA_RSRC_LEGACY_MASK) + flags |= PCI_VGA_STATE_CHANGE_BRIDGE; + + pci_set_vga_state(vgadev->pdev, true, pci_bits, flags); + + vgadev->owns |= wants; +lock_them: + vgadev->locks |= (rsrc & VGA_RSRC_LEGACY_MASK); + if (rsrc & VGA_RSRC_LEGACY_IO) + vgadev->io_lock_cnt++; + if (rsrc & VGA_RSRC_LEGACY_MEM) + vgadev->mem_lock_cnt++; + if (rsrc & VGA_RSRC_NORMAL_IO) + vgadev->io_norm_cnt++; + if (rsrc & VGA_RSRC_NORMAL_MEM) + vgadev->mem_norm_cnt++; + + return NULL; +} + +static void __vga_put(struct vga_device *vgadev, unsigned int rsrc) +{ + struct device *dev = &vgadev->pdev->dev; + unsigned int old_locks = vgadev->locks; + + vgaarb_dbg(dev, "%s\n", __func__); + + /* Update our counters, and account for equivalent legacy resources + * if we decode them + */ + if ((rsrc & VGA_RSRC_NORMAL_IO) && vgadev->io_norm_cnt > 0) { + vgadev->io_norm_cnt--; + if (vgadev->decodes & VGA_RSRC_LEGACY_IO) + rsrc |= VGA_RSRC_LEGACY_IO; + } + if ((rsrc & VGA_RSRC_NORMAL_MEM) && vgadev->mem_norm_cnt > 0) { + vgadev->mem_norm_cnt--; + if (vgadev->decodes & VGA_RSRC_LEGACY_MEM) + rsrc |= VGA_RSRC_LEGACY_MEM; + } + if ((rsrc & VGA_RSRC_LEGACY_IO) && vgadev->io_lock_cnt > 0) + vgadev->io_lock_cnt--; + if ((rsrc & VGA_RSRC_LEGACY_MEM) && vgadev->mem_lock_cnt > 0) + vgadev->mem_lock_cnt--; + + /* Just clear lock bits, we do lazy operations so we don't really + * have to bother about anything else at this point + */ + if (vgadev->io_lock_cnt == 0) + vgadev->locks &= ~VGA_RSRC_LEGACY_IO; + if (vgadev->mem_lock_cnt == 0) + vgadev->locks &= ~VGA_RSRC_LEGACY_MEM; + + /* Kick the wait queue in case somebody was waiting if we actually + * released something + */ + if (old_locks != vgadev->locks) + wake_up_all(&vga_wait_queue); +} + +/** + * vga_get - acquire & locks VGA resources + * @pdev: pci device of the VGA card or NULL for the system default + * @rsrc: bit mask of resources to acquire and lock + * @interruptible: blocking should be interruptible by signals ? + * + * This function acquires VGA resources for the given card and mark those + * resources locked. If the resource requested are "normal" (and not legacy) + * resources, the arbiter will first check whether the card is doing legacy + * decoding for that type of resource. If yes, the lock is "converted" into a + * legacy resource lock. + * + * The arbiter will first look for all VGA cards that might conflict and disable + * their IOs and/or Memory access, including VGA forwarding on P2P bridges if + * necessary, so that the requested resources can be used. Then, the card is + * marked as locking these resources and the IO and/or Memory accesses are + * enabled on the card (including VGA forwarding on parent P2P bridges if any). + * + * This function will block if some conflicting card is already locking one of + * the required resources (or any resource on a different bus segment, since P2P + * bridges don't differentiate VGA memory and IO afaik). You can indicate + * whether this blocking should be interruptible by a signal (for userland + * interface) or not. + * + * Must not be called at interrupt time or in atomic context. If the card + * already owns the resources, the function succeeds. Nested calls are + * supported (a per-resource counter is maintained) + * + * On success, release the VGA resource again with vga_put(). + * + * Returns: + * + * 0 on success, negative error code on failure. + */ +int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible) +{ + struct vga_device *vgadev, *conflict; + unsigned long flags; + wait_queue_entry_t wait; + int rc = 0; + + vga_check_first_use(); + /* The one who calls us should check for this, but lets be sure... */ + if (pdev == NULL) + pdev = vga_default_device(); + if (pdev == NULL) + return 0; + + for (;;) { + spin_lock_irqsave(&vga_lock, flags); + vgadev = vgadev_find(pdev); + if (vgadev == NULL) { + spin_unlock_irqrestore(&vga_lock, flags); + rc = -ENODEV; + break; + } + conflict = __vga_tryget(vgadev, rsrc); + spin_unlock_irqrestore(&vga_lock, flags); + if (conflict == NULL) + break; + + + /* We have a conflict, we wait until somebody kicks the + * work queue. Currently we have one work queue that we + * kick each time some resources are released, but it would + * be fairly easy to have a per device one so that we only + * need to attach to the conflicting device + */ + init_waitqueue_entry(&wait, current); + add_wait_queue(&vga_wait_queue, &wait); + set_current_state(interruptible ? + TASK_INTERRUPTIBLE : + TASK_UNINTERRUPTIBLE); + if (interruptible && signal_pending(current)) { + __set_current_state(TASK_RUNNING); + remove_wait_queue(&vga_wait_queue, &wait); + rc = -ERESTARTSYS; + break; + } + schedule(); + remove_wait_queue(&vga_wait_queue, &wait); + } + return rc; +} +EXPORT_SYMBOL(vga_get); + +/** + * vga_tryget - try to acquire & lock legacy VGA resources + * @pdev: pci devivce of VGA card or NULL for system default + * @rsrc: bit mask of resources to acquire and lock + * + * This function performs the same operation as vga_get(), but will return an + * error (-EBUSY) instead of blocking if the resources are already locked by + * another card. It can be called in any context + * + * On success, release the VGA resource again with vga_put(). + * + * Returns: + * + * 0 on success, negative error code on failure. + */ +static int vga_tryget(struct pci_dev *pdev, unsigned int rsrc) +{ + struct vga_device *vgadev; + unsigned long flags; + int rc = 0; + + vga_check_first_use(); + + /* The one who calls us should check for this, but lets be sure... */ + if (pdev == NULL) + pdev = vga_default_device(); + if (pdev == NULL) + return 0; + spin_lock_irqsave(&vga_lock, flags); + vgadev = vgadev_find(pdev); + if (vgadev == NULL) { + rc = -ENODEV; + goto bail; + } + if (__vga_tryget(vgadev, rsrc)) + rc = -EBUSY; +bail: + spin_unlock_irqrestore(&vga_lock, flags); + return rc; +} + +/** + * vga_put - release lock on legacy VGA resources + * @pdev: pci device of VGA card or NULL for system default + * @rsrc: but mask of resource to release + * + * This fuction releases resources previously locked by vga_get() or + * vga_tryget(). The resources aren't disabled right away, so that a subsequence + * vga_get() on the same card will succeed immediately. Resources have a + * counter, so locks are only released if the counter reaches 0. + */ +void vga_put(struct pci_dev *pdev, unsigned int rsrc) +{ + struct vga_device *vgadev; + unsigned long flags; + + /* The one who calls us should check for this, but lets be sure... */ + if (pdev == NULL) + pdev = vga_default_device(); + if (pdev == NULL) + return; + spin_lock_irqsave(&vga_lock, flags); + vgadev = vgadev_find(pdev); + if (vgadev == NULL) + goto bail; + __vga_put(vgadev, rsrc); +bail: + spin_unlock_irqrestore(&vga_lock, flags); +} +EXPORT_SYMBOL(vga_put); + +/* + * Rules for using a bridge to control a VGA descendant decoding: if a bridge + * has only one VGA descendant then it can be used to control the VGA routing + * for that device. It should always use the bridge closest to the device to + * control it. If a bridge has a direct VGA descendant, but also have a sub- + * bridge VGA descendant then we cannot use that bridge to control the direct + * VGA descendant. So for every device we register, we need to iterate all + * its parent bridges so we can invalidate any devices using them properly. + */ +static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev) +{ + struct vga_device *same_bridge_vgadev; + struct pci_bus *new_bus, *bus; + struct pci_dev *new_bridge, *bridge; + + vgadev->bridge_has_one_vga = true; + + if (list_empty(&vga_list)) + return; + + /* okay iterate the new devices bridge hierarachy */ + new_bus = vgadev->pdev->bus; + while (new_bus) { + new_bridge = new_bus->self; + + /* go through list of devices already registered */ + list_for_each_entry(same_bridge_vgadev, &vga_list, list) { + bus = same_bridge_vgadev->pdev->bus; + bridge = bus->self; + + /* see if the share a bridge with this device */ + if (new_bridge == bridge) { + /* + * If their direct parent bridge is the same + * as any bridge of this device then it can't + * be used for that device. + */ + same_bridge_vgadev->bridge_has_one_vga = false; + } + + /* + * Now iterate the previous devices bridge hierarchy. + * If the new devices parent bridge is in the other + * devices hierarchy then we can't use it to control + * this device + */ + while (bus) { + bridge = bus->self; + + if (bridge && bridge == vgadev->pdev->bus->self) + vgadev->bridge_has_one_vga = false; + + bus = bus->parent; + } + } + new_bus = new_bus->parent; + } +} + +/* + * Currently, we assume that the "initial" setup of the system is + * not sane, that is we come up with conflicting devices and let + * the arbiter's client decides if devices decodes or not legacy + * things. + */ +static bool vga_arbiter_add_pci_device(struct pci_dev *pdev) +{ + struct vga_device *vgadev; + unsigned long flags; + struct pci_bus *bus; + struct pci_dev *bridge; + u16 cmd; + + /* Only deal with VGA class devices */ + if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA) + return false; + + /* Allocate structure */ + vgadev = kzalloc(sizeof(struct vga_device), GFP_KERNEL); + if (vgadev == NULL) { + vgaarb_err(&pdev->dev, "failed to allocate VGA arbiter data\n"); + /* + * What to do on allocation failure ? For now, let's just do + * nothing, I'm not sure there is anything saner to be done. + */ + return false; + } + + /* Take lock & check for duplicates */ + spin_lock_irqsave(&vga_lock, flags); + if (vgadev_find(pdev) != NULL) { + BUG_ON(1); + goto fail; + } + vgadev->pdev = pdev; + + /* By default, assume we decode everything */ + vgadev->decodes = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM | + VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM; + + /* by default mark it as decoding */ + vga_decode_count++; + /* Mark that we "own" resources based on our enables, we will + * clear that below if the bridge isn't forwarding + */ + pci_read_config_word(pdev, PCI_COMMAND, &cmd); + if (cmd & PCI_COMMAND_IO) + vgadev->owns |= VGA_RSRC_LEGACY_IO; + if (cmd & PCI_COMMAND_MEMORY) + vgadev->owns |= VGA_RSRC_LEGACY_MEM; + + /* Check if VGA cycles can get down to us */ + bus = pdev->bus; + while (bus) { + bridge = bus->self; + if (bridge) { + u16 l; + + pci_read_config_word(bridge, PCI_BRIDGE_CONTROL, &l); + if (!(l & PCI_BRIDGE_CTL_VGA)) { + vgadev->owns = 0; + break; + } + } + bus = bus->parent; + } + + /* Deal with VGA default device. Use first enabled one + * by default if arch doesn't have it's own hook + */ + if (vga_default == NULL && + ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) { + vgaarb_info(&pdev->dev, "setting as boot VGA device\n"); + vga_set_default_device(pdev); + } + + vga_arbiter_check_bridge_sharing(vgadev); + + /* Add to the list */ + list_add_tail(&vgadev->list, &vga_list); + vga_count++; + vgaarb_info(&pdev->dev, "VGA device added: decodes=%s,owns=%s,locks=%s\n", + vga_iostate_to_str(vgadev->decodes), + vga_iostate_to_str(vgadev->owns), + vga_iostate_to_str(vgadev->locks)); + + spin_unlock_irqrestore(&vga_lock, flags); + return true; +fail: + spin_unlock_irqrestore(&vga_lock, flags); + kfree(vgadev); + return false; +} + +static bool vga_arbiter_del_pci_device(struct pci_dev *pdev) +{ + struct vga_device *vgadev; + unsigned long flags; + bool ret = true; + + spin_lock_irqsave(&vga_lock, flags); + vgadev = vgadev_find(pdev); + if (vgadev == NULL) { + ret = false; + goto bail; + } + + if (vga_default == pdev) + vga_set_default_device(NULL); + + if (vgadev->decodes & (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM)) + vga_decode_count--; + + /* Remove entry from list */ + list_del(&vgadev->list); + vga_count--; + /* Notify userland driver that the device is gone so it discards + * it's copies of the pci_dev pointer + */ + vga_arb_device_card_gone(pdev); + + /* Wake up all possible waiters */ + wake_up_all(&vga_wait_queue); +bail: + spin_unlock_irqrestore(&vga_lock, flags); + kfree(vgadev); + return ret; +} + +/* this is called with the lock */ +static inline void vga_update_device_decodes(struct vga_device *vgadev, + int new_decodes) +{ + struct device *dev = &vgadev->pdev->dev; + int old_decodes, decodes_removed, decodes_unlocked; + + old_decodes = vgadev->decodes; + decodes_removed = ~new_decodes & old_decodes; + decodes_unlocked = vgadev->locks & decodes_removed; + vgadev->decodes = new_decodes; + + vgaarb_info(dev, "changed VGA decodes: olddecodes=%s,decodes=%s:owns=%s\n", + vga_iostate_to_str(old_decodes), + vga_iostate_to_str(vgadev->decodes), + vga_iostate_to_str(vgadev->owns)); + + /* if we removed locked decodes, lock count goes to zero, and release */ + if (decodes_unlocked) { + if (decodes_unlocked & VGA_RSRC_LEGACY_IO) + vgadev->io_lock_cnt = 0; + if (decodes_unlocked & VGA_RSRC_LEGACY_MEM) + vgadev->mem_lock_cnt = 0; + __vga_put(vgadev, decodes_unlocked); + } + + /* change decodes counter */ + if (old_decodes & VGA_RSRC_LEGACY_MASK && + !(new_decodes & VGA_RSRC_LEGACY_MASK)) + vga_decode_count--; + if (!(old_decodes & VGA_RSRC_LEGACY_MASK) && + new_decodes & VGA_RSRC_LEGACY_MASK) + vga_decode_count++; + vgaarb_dbg(dev, "decoding count now is: %d\n", vga_decode_count); +} + +static void __vga_set_legacy_decoding(struct pci_dev *pdev, + unsigned int decodes, + bool userspace) +{ + struct vga_device *vgadev; + unsigned long flags; + + decodes &= VGA_RSRC_LEGACY_MASK; + + spin_lock_irqsave(&vga_lock, flags); + vgadev = vgadev_find(pdev); + if (vgadev == NULL) + goto bail; + + /* don't let userspace futz with kernel driver decodes */ + if (userspace && vgadev->set_decode) + goto bail; + + /* update the device decodes + counter */ + vga_update_device_decodes(vgadev, decodes); + + /* XXX if somebody is going from "doesn't decode" to "decodes" state + * here, additional care must be taken as we may have pending owner + * ship of non-legacy region ... + */ +bail: + spin_unlock_irqrestore(&vga_lock, flags); +} + +/** + * vga_set_legacy_decoding + * @pdev: pci device of the VGA card + * @decodes: bit mask of what legacy regions the card decodes + * + * Indicates to the arbiter if the card decodes legacy VGA IOs, legacy VGA + * Memory, both, or none. All cards default to both, the card driver (fbdev for + * example) should tell the arbiter if it has disabled legacy decoding, so the + * card can be left out of the arbitration process (and can be safe to take + * interrupts at any time. + */ +void vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes) +{ + __vga_set_legacy_decoding(pdev, decodes, false); +} +EXPORT_SYMBOL(vga_set_legacy_decoding); + +/** + * vga_client_register - register or unregister a VGA arbitration client + * @pdev: pci device of the VGA client + * @set_decode: vga decode change callback + * + * Clients have two callback mechanisms they can use. + * + * @set_decode callback: If a client can disable its GPU VGA resource, it + * will get a callback from this to set the encode/decode state. + * + * Rationale: we cannot disable VGA decode resources unconditionally some single + * GPU laptops seem to require ACPI or BIOS access to the VGA registers to + * control things like backlights etc. Hopefully newer multi-GPU laptops do + * something saner, and desktops won't have any special ACPI for this. The + * driver will get a callback when VGA arbitration is first used by userspace + * since some older X servers have issues. + * + * This function does not check whether a client for @pdev has been registered + * already. + * + * To unregister just call vga_client_unregister(). + * + * Returns: 0 on success, -1 on failure + */ +int vga_client_register(struct pci_dev *pdev, + unsigned int (*set_decode)(struct pci_dev *pdev, bool decode)) +{ + int ret = -ENODEV; + struct vga_device *vgadev; + unsigned long flags; + + spin_lock_irqsave(&vga_lock, flags); + vgadev = vgadev_find(pdev); + if (!vgadev) + goto bail; + + vgadev->set_decode = set_decode; + ret = 0; + +bail: + spin_unlock_irqrestore(&vga_lock, flags); + return ret; + +} +EXPORT_SYMBOL(vga_client_register); + +/* + * Char driver implementation + * + * Semantics is: + * + * open : open user instance of the arbitrer. by default, it's + * attached to the default VGA device of the system. + * + * close : close user instance, release locks + * + * read : return a string indicating the status of the target. + * an IO state string is of the form {io,mem,io+mem,none}, + * mc and ic are respectively mem and io lock counts (for + * debugging/diagnostic only). "decodes" indicate what the + * card currently decodes, "owns" indicates what is currently + * enabled on it, and "locks" indicates what is locked by this + * card. If the card is unplugged, we get "invalid" then for + * card_ID and an -ENODEV error is returned for any command + * until a new card is targeted + * + * ",decodes=,owns=,locks= (ic,mc)" + * + * write : write a command to the arbiter. List of commands is: + * + * target : switch target to card (see below) + * lock : acquires locks on target ("none" is invalid io_state) + * trylock : non-blocking acquire locks on target + * unlock : release locks on target + * unlock all : release all locks on target held by this user + * decodes : set the legacy decoding attributes for the card + * + * poll : event if something change on any card (not just the target) + * + * card_ID is of the form "PCI:domain:bus:dev.fn". It can be set to "default" + * to go back to the system default card (TODO: not implemented yet). + * Currently, only PCI is supported as a prefix, but the userland API may + * support other bus types in the future, even if the current kernel + * implementation doesn't. + * + * Note about locks: + * + * The driver keeps track of which user has what locks on which card. It + * supports stacking, like the kernel one. This complexifies the implementation + * a bit, but makes the arbiter more tolerant to userspace problems and able + * to properly cleanup in all cases when a process dies. + * Currently, a max of 16 cards simultaneously can have locks issued from + * userspace for a given user (file descriptor instance) of the arbiter. + * + * If the device is hot-unplugged, there is a hook inside the module to notify + * they being added/removed in the system and automatically added/removed in + * the arbiter. + */ + +#define MAX_USER_CARDS CONFIG_VGA_ARB_MAX_GPUS +#define PCI_INVALID_CARD ((struct pci_dev *)-1UL) + +/* + * Each user has an array of these, tracking which cards have locks + */ +struct vga_arb_user_card { + struct pci_dev *pdev; + unsigned int mem_cnt; + unsigned int io_cnt; +}; + +struct vga_arb_private { + struct list_head list; + struct pci_dev *target; + struct vga_arb_user_card cards[MAX_USER_CARDS]; + spinlock_t lock; +}; + +static LIST_HEAD(vga_user_list); +static DEFINE_SPINLOCK(vga_user_lock); + + +/* + * This function gets a string in the format: "PCI:domain:bus:dev.fn" and + * returns the respective values. If the string is not in this format, + * it returns 0. + */ +static int vga_pci_str_to_vars(char *buf, int count, unsigned int *domain, + unsigned int *bus, unsigned int *devfn) +{ + int n; + unsigned int slot, func; + + + n = sscanf(buf, "PCI:%x:%x:%x.%x", domain, bus, &slot, &func); + if (n != 4) + return 0; + + *devfn = PCI_DEVFN(slot, func); + + return 1; +} + +static ssize_t vga_arb_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + struct vga_arb_private *priv = file->private_data; + struct vga_device *vgadev; + struct pci_dev *pdev; + unsigned long flags; + size_t len; + int rc; + char *lbuf; + + lbuf = kmalloc(1024, GFP_KERNEL); + if (lbuf == NULL) + return -ENOMEM; + + /* Shields against vga_arb_device_card_gone (pci_dev going + * away), and allows access to vga list + */ + spin_lock_irqsave(&vga_lock, flags); + + /* If we are targeting the default, use it */ + pdev = priv->target; + if (pdev == NULL || pdev == PCI_INVALID_CARD) { + spin_unlock_irqrestore(&vga_lock, flags); + len = sprintf(lbuf, "invalid"); + goto done; + } + + /* Find card vgadev structure */ + vgadev = vgadev_find(pdev); + if (vgadev == NULL) { + /* Wow, it's not in the list, that shouldn't happen, + * let's fix us up and return invalid card + */ + if (pdev == priv->target) + vga_arb_device_card_gone(pdev); + spin_unlock_irqrestore(&vga_lock, flags); + len = sprintf(lbuf, "invalid"); + goto done; + } + + /* Fill the buffer with infos */ + len = snprintf(lbuf, 1024, + "count:%d,PCI:%s,decodes=%s,owns=%s,locks=%s(%d:%d)\n", + vga_decode_count, pci_name(pdev), + vga_iostate_to_str(vgadev->decodes), + vga_iostate_to_str(vgadev->owns), + vga_iostate_to_str(vgadev->locks), + vgadev->io_lock_cnt, vgadev->mem_lock_cnt); + + spin_unlock_irqrestore(&vga_lock, flags); +done: + + /* Copy that to user */ + if (len > count) + len = count; + rc = copy_to_user(buf, lbuf, len); + kfree(lbuf); + if (rc) + return -EFAULT; + return len; +} + +/* + * TODO: To avoid parsing inside kernel and to improve the speed we may + * consider use ioctl here + */ +static ssize_t vga_arb_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct vga_arb_private *priv = file->private_data; + struct vga_arb_user_card *uc = NULL; + struct pci_dev *pdev; + + unsigned int io_state; + + char kbuf[64], *curr_pos; + size_t remaining = count; + + int ret_val; + int i; + + if (count >= sizeof(kbuf)) + return -EINVAL; + if (copy_from_user(kbuf, buf, count)) + return -EFAULT; + curr_pos = kbuf; + kbuf[count] = '\0'; /* Just to make sure... */ + + if (strncmp(curr_pos, "lock ", 5) == 0) { + curr_pos += 5; + remaining -= 5; + + pr_debug("client 0x%p called 'lock'\n", priv); + + if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { + ret_val = -EPROTO; + goto done; + } + if (io_state == VGA_RSRC_NONE) { + ret_val = -EPROTO; + goto done; + } + + pdev = priv->target; + if (priv->target == NULL) { + ret_val = -ENODEV; + goto done; + } + + vga_get_uninterruptible(pdev, io_state); + + /* Update the client's locks lists... */ + for (i = 0; i < MAX_USER_CARDS; i++) { + if (priv->cards[i].pdev == pdev) { + if (io_state & VGA_RSRC_LEGACY_IO) + priv->cards[i].io_cnt++; + if (io_state & VGA_RSRC_LEGACY_MEM) + priv->cards[i].mem_cnt++; + break; + } + } + + ret_val = count; + goto done; + } else if (strncmp(curr_pos, "unlock ", 7) == 0) { + curr_pos += 7; + remaining -= 7; + + pr_debug("client 0x%p called 'unlock'\n", priv); + + if (strncmp(curr_pos, "all", 3) == 0) + io_state = VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; + else { + if (!vga_str_to_iostate + (curr_pos, remaining, &io_state)) { + ret_val = -EPROTO; + goto done; + } + /* TODO: Add this? + if (io_state == VGA_RSRC_NONE) { + ret_val = -EPROTO; + goto done; + } + */ + } + + pdev = priv->target; + if (priv->target == NULL) { + ret_val = -ENODEV; + goto done; + } + for (i = 0; i < MAX_USER_CARDS; i++) { + if (priv->cards[i].pdev == pdev) + uc = &priv->cards[i]; + } + + if (!uc) { + ret_val = -EINVAL; + goto done; + } + + if (io_state & VGA_RSRC_LEGACY_IO && uc->io_cnt == 0) { + ret_val = -EINVAL; + goto done; + } + + if (io_state & VGA_RSRC_LEGACY_MEM && uc->mem_cnt == 0) { + ret_val = -EINVAL; + goto done; + } + + vga_put(pdev, io_state); + + if (io_state & VGA_RSRC_LEGACY_IO) + uc->io_cnt--; + if (io_state & VGA_RSRC_LEGACY_MEM) + uc->mem_cnt--; + + ret_val = count; + goto done; + } else if (strncmp(curr_pos, "trylock ", 8) == 0) { + curr_pos += 8; + remaining -= 8; + + pr_debug("client 0x%p called 'trylock'\n", priv); + + if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { + ret_val = -EPROTO; + goto done; + } + /* TODO: Add this? + if (io_state == VGA_RSRC_NONE) { + ret_val = -EPROTO; + goto done; + } + */ + + pdev = priv->target; + if (priv->target == NULL) { + ret_val = -ENODEV; + goto done; + } + + if (vga_tryget(pdev, io_state)) { + /* Update the client's locks lists... */ + for (i = 0; i < MAX_USER_CARDS; i++) { + if (priv->cards[i].pdev == pdev) { + if (io_state & VGA_RSRC_LEGACY_IO) + priv->cards[i].io_cnt++; + if (io_state & VGA_RSRC_LEGACY_MEM) + priv->cards[i].mem_cnt++; + break; + } + } + ret_val = count; + goto done; + } else { + ret_val = -EBUSY; + goto done; + } + + } else if (strncmp(curr_pos, "target ", 7) == 0) { + unsigned int domain, bus, devfn; + struct vga_device *vgadev; + + curr_pos += 7; + remaining -= 7; + pr_debug("client 0x%p called 'target'\n", priv); + /* if target is default */ + if (!strncmp(curr_pos, "default", 7)) + pdev = pci_dev_get(vga_default_device()); + else { + if (!vga_pci_str_to_vars(curr_pos, remaining, + &domain, &bus, &devfn)) { + ret_val = -EPROTO; + goto done; + } + pdev = pci_get_domain_bus_and_slot(domain, bus, devfn); + if (!pdev) { + pr_debug("invalid PCI address %04x:%02x:%02x.%x\n", + domain, bus, PCI_SLOT(devfn), + PCI_FUNC(devfn)); + ret_val = -ENODEV; + goto done; + } + + pr_debug("%s ==> %04x:%02x:%02x.%x pdev %p\n", curr_pos, + domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn), + pdev); + } + + vgadev = vgadev_find(pdev); + pr_debug("vgadev %p\n", vgadev); + if (vgadev == NULL) { + if (pdev) { + vgaarb_dbg(&pdev->dev, "not a VGA device\n"); + pci_dev_put(pdev); + } + + ret_val = -ENODEV; + goto done; + } + + priv->target = pdev; + for (i = 0; i < MAX_USER_CARDS; i++) { + if (priv->cards[i].pdev == pdev) + break; + if (priv->cards[i].pdev == NULL) { + priv->cards[i].pdev = pdev; + priv->cards[i].io_cnt = 0; + priv->cards[i].mem_cnt = 0; + break; + } + } + if (i == MAX_USER_CARDS) { + vgaarb_dbg(&pdev->dev, "maximum user cards (%d) number reached, ignoring this one!\n", + MAX_USER_CARDS); + pci_dev_put(pdev); + /* XXX: which value to return? */ + ret_val = -ENOMEM; + goto done; + } + + ret_val = count; + pci_dev_put(pdev); + goto done; + + + } else if (strncmp(curr_pos, "decodes ", 8) == 0) { + curr_pos += 8; + remaining -= 8; + pr_debug("client 0x%p called 'decodes'\n", priv); + + if (!vga_str_to_iostate(curr_pos, remaining, &io_state)) { + ret_val = -EPROTO; + goto done; + } + pdev = priv->target; + if (priv->target == NULL) { + ret_val = -ENODEV; + goto done; + } + + __vga_set_legacy_decoding(pdev, io_state, true); + ret_val = count; + goto done; + } + /* If we got here, the message written is not part of the protocol! */ + return -EPROTO; + +done: + return ret_val; +} + +static __poll_t vga_arb_fpoll(struct file *file, poll_table *wait) +{ + pr_debug("%s\n", __func__); + + poll_wait(file, &vga_wait_queue, wait); + return EPOLLIN; +} + +static int vga_arb_open(struct inode *inode, struct file *file) +{ + struct vga_arb_private *priv; + unsigned long flags; + + pr_debug("%s\n", __func__); + + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (priv == NULL) + return -ENOMEM; + spin_lock_init(&priv->lock); + file->private_data = priv; + + spin_lock_irqsave(&vga_user_lock, flags); + list_add(&priv->list, &vga_user_list); + spin_unlock_irqrestore(&vga_user_lock, flags); + + /* Set the client' lists of locks */ + priv->target = vga_default_device(); /* Maybe this is still null! */ + priv->cards[0].pdev = priv->target; + priv->cards[0].io_cnt = 0; + priv->cards[0].mem_cnt = 0; + + + return 0; +} + +static int vga_arb_release(struct inode *inode, struct file *file) +{ + struct vga_arb_private *priv = file->private_data; + struct vga_arb_user_card *uc; + unsigned long flags; + int i; + + pr_debug("%s\n", __func__); + + spin_lock_irqsave(&vga_user_lock, flags); + list_del(&priv->list); + for (i = 0; i < MAX_USER_CARDS; i++) { + uc = &priv->cards[i]; + if (uc->pdev == NULL) + continue; + vgaarb_dbg(&uc->pdev->dev, "uc->io_cnt == %d, uc->mem_cnt == %d\n", + uc->io_cnt, uc->mem_cnt); + while (uc->io_cnt--) + vga_put(uc->pdev, VGA_RSRC_LEGACY_IO); + while (uc->mem_cnt--) + vga_put(uc->pdev, VGA_RSRC_LEGACY_MEM); + } + spin_unlock_irqrestore(&vga_user_lock, flags); + + kfree(priv); + + return 0; +} + +static void vga_arb_device_card_gone(struct pci_dev *pdev) +{ +} + +/* + * callback any registered clients to let them know we have a + * change in VGA cards + */ +static void vga_arbiter_notify_clients(void) +{ + struct vga_device *vgadev; + unsigned long flags; + uint32_t new_decodes; + bool new_state; + + if (!vga_arbiter_used) + return; + + spin_lock_irqsave(&vga_lock, flags); + list_for_each_entry(vgadev, &vga_list, list) { + if (vga_count > 1) + new_state = false; + else + new_state = true; + if (vgadev->set_decode) { + new_decodes = vgadev->set_decode(vgadev->pdev, + new_state); + vga_update_device_decodes(vgadev, new_decodes); + } + } + spin_unlock_irqrestore(&vga_lock, flags); +} + +static int pci_notify(struct notifier_block *nb, unsigned long action, + void *data) +{ + struct device *dev = data; + struct pci_dev *pdev = to_pci_dev(dev); + bool notify = false; + + vgaarb_dbg(dev, "%s\n", __func__); + + /* For now we're only intereted in devices added and removed. I didn't + * test this thing here, so someone needs to double check for the + * cases of hotplugable vga cards. */ + if (action == BUS_NOTIFY_ADD_DEVICE) + notify = vga_arbiter_add_pci_device(pdev); + else if (action == BUS_NOTIFY_DEL_DEVICE) + notify = vga_arbiter_del_pci_device(pdev); + + if (notify) + vga_arbiter_notify_clients(); + return 0; +} + +static struct notifier_block pci_notifier = { + .notifier_call = pci_notify, +}; + +static const struct file_operations vga_arb_device_fops = { + .read = vga_arb_read, + .write = vga_arb_write, + .poll = vga_arb_fpoll, + .open = vga_arb_open, + .release = vga_arb_release, + .llseek = noop_llseek, +}; + +static struct miscdevice vga_arb_device = { + MISC_DYNAMIC_MINOR, "vga_arbiter", &vga_arb_device_fops +}; + +#if defined(CONFIG_ACPI) +static bool vga_arb_integrated_gpu(struct device *dev) +{ + struct acpi_device *adev = ACPI_COMPANION(dev); + + return adev && !strcmp(acpi_device_hid(adev), ACPI_VIDEO_HID); +} +#else +static bool vga_arb_integrated_gpu(struct device *dev) +{ + return false; +} +#endif + +static void __init vga_arb_select_default_device(void) +{ + struct pci_dev *pdev, *found = NULL; + struct vga_device *vgadev; + +#if defined(CONFIG_X86) || defined(CONFIG_IA64) + u64 base = screen_info.lfb_base; + u64 size = screen_info.lfb_size; + u64 limit; + resource_size_t start, end; + unsigned long flags; + int i; + + if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) + base |= (u64)screen_info.ext_lfb_base << 32; + + limit = base + size; + + list_for_each_entry(vgadev, &vga_list, list) { + struct device *dev = &vgadev->pdev->dev; + /* + * Override vga_arbiter_add_pci_device()'s I/O based detection + * as it may take the wrong device (e.g. on Apple system under + * EFI). + * + * Select the device owning the boot framebuffer if there is + * one. + */ + + /* Does firmware framebuffer belong to us? */ + for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) { + flags = pci_resource_flags(vgadev->pdev, i); + + if ((flags & IORESOURCE_MEM) == 0) + continue; + + start = pci_resource_start(vgadev->pdev, i); + end = pci_resource_end(vgadev->pdev, i); + + if (!start || !end) + continue; + + if (base < start || limit >= end) + continue; + + if (!vga_default_device()) + vgaarb_info(dev, "setting as boot device\n"); + else if (vgadev->pdev != vga_default_device()) + vgaarb_info(dev, "overriding boot device\n"); + vga_set_default_device(vgadev->pdev); + } + } +#endif + + if (!vga_default_device()) { + list_for_each_entry_reverse(vgadev, &vga_list, list) { + struct device *dev = &vgadev->pdev->dev; + u16 cmd; + + pdev = vgadev->pdev; + pci_read_config_word(pdev, PCI_COMMAND, &cmd); + if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) { + found = pdev; + if (vga_arb_integrated_gpu(dev)) + break; + } + } + } + + if (found) { + vgaarb_info(&found->dev, "setting as boot device (VGA legacy resources not available)\n"); + vga_set_default_device(found); + return; + } + + if (!vga_default_device()) { + vgadev = list_first_entry_or_null(&vga_list, + struct vga_device, list); + if (vgadev) { + struct device *dev = &vgadev->pdev->dev; + vgaarb_info(dev, "setting as boot device (VGA legacy resources not available)\n"); + vga_set_default_device(vgadev->pdev); + } + } +} + +static int __init vga_arb_device_init(void) +{ + int rc; + struct pci_dev *pdev; + struct vga_device *vgadev; + + rc = misc_register(&vga_arb_device); + if (rc < 0) + pr_err("error %d registering device\n", rc); + + bus_register_notifier(&pci_bus_type, &pci_notifier); + + /* We add all PCI devices satisfying VGA class in the arbiter by + * default */ + pdev = NULL; + while ((pdev = + pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, + PCI_ANY_ID, pdev)) != NULL) + vga_arbiter_add_pci_device(pdev); + + list_for_each_entry(vgadev, &vga_list, list) { + struct device *dev = &vgadev->pdev->dev; + + if (vgadev->bridge_has_one_vga) + vgaarb_info(dev, "bridge control possible\n"); + else + vgaarb_info(dev, "no bridge control possible\n"); + } + + vga_arb_select_default_device(); + + pr_info("loaded\n"); + return rc; +} +subsys_initcall_sync(vga_arb_device_init); -- cgit 1.4.1 From aa457ff1b2be72c0d89ee2118769859e513e6fc8 Mon Sep 17 00:00:00 2001 From: Jeffrey Hugo Date: Mon, 7 Mar 2022 08:32:36 -0700 Subject: drm/doc: Clarify what ioctls can be used on render nodes The documentation for render nodes indicates that only "PRIME-related" ioctls are valid on render nodes, but the documentation does not clarify what that means. If the reader is not familiar with PRIME, they may beleive this to be only the ioctls with "PRIME" in the name and not other ioctls such as set of syncobj ioctls. Clarify the situation for the reader by referencing where the reader will find a current list of valid ioctls. Signed-off-by: Jeffrey Hugo Acked-by: Pekka Paalanen Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/1646667156-16366-1-git-send-email-quic_jhugo@quicinc.com --- Documentation/gpu/drm-uapi.rst | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'Documentation/gpu') diff --git a/Documentation/gpu/drm-uapi.rst b/Documentation/gpu/drm-uapi.rst index 199afb503ab1..ce47b4292481 100644 --- a/Documentation/gpu/drm-uapi.rst +++ b/Documentation/gpu/drm-uapi.rst @@ -148,7 +148,9 @@ clients together with the legacy drmAuth authentication procedure. If a driver advertises render node support, DRM core will create a separate render node called renderD. There will be one render node per device. No ioctls except PRIME-related ioctls will be allowed on -this node. Especially GEM_OPEN will be explicitly prohibited. Render +this node. Especially GEM_OPEN will be explicitly prohibited. For a +complete list of driver-independent ioctls that can be used on render +nodes, see the ioctls marked DRM_RENDER_ALLOW in drm_ioctl.c Render nodes are designed to avoid the buffer-leaks, which occur if clients guess the flink names or mmap offsets on the legacy interface. Additionally to this basic interface, drivers must mark their -- cgit 1.4.1