From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9=20Fabian=20Silva=20Delgado?=
 <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 include/linux/vgaarb.h | 254 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 254 insertions(+)
 create mode 100644 include/linux/vgaarb.h

(limited to 'include/linux/vgaarb.h')

diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h
new file mode 100644
index 000000000..8c3b412d8
--- /dev/null
+++ b/include/linux/vgaarb.h
@@ -0,0 +1,254 @@
+/*
+ * The VGA aribiter manages VGA space routing and VGA resource decode to
+ * allow multiple VGA devices to be used in a system in a safe way.
+ *
+ * (C) Copyright 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>
+ * (C) Copyright 2007 Paulo R. Zanoni <przanoni@gmail.com>
+ * (C) Copyright 2007, 2009 Tiago Vignatti <vignatti@freedesktop.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#ifndef LINUX_VGA_H
+#define LINUX_VGA_H
+
+#include <video/vga.h>
+
+/* Legacy VGA regions */
+#define VGA_RSRC_NONE	       0x00
+#define VGA_RSRC_LEGACY_IO     0x01
+#define VGA_RSRC_LEGACY_MEM    0x02
+#define VGA_RSRC_LEGACY_MASK   (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM)
+/* Non-legacy access */
+#define VGA_RSRC_NORMAL_IO     0x04
+#define VGA_RSRC_NORMAL_MEM    0x08
+
+/* Passing that instead of a pci_dev to use the system "default"
+ * device, that is the one used by vgacon. Archs will probably
+ * have to provide their own vga_default_device();
+ */
+#define VGA_DEFAULT_DEVICE     (NULL)
+
+struct pci_dev;
+
+/* For use by clients */
+
+/**
+ *     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.
+ */
+#if defined(CONFIG_VGA_ARB)
+extern void vga_set_legacy_decoding(struct pci_dev *pdev,
+				    unsigned int decodes);
+#else
+static inline void vga_set_legacy_decoding(struct pci_dev *pdev,
+					   unsigned int decodes) { };
+#endif
+
+/**
+ *     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 accesse 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 differenciate 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)
+ */
+
+#if defined(CONFIG_VGA_ARB)
+extern int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible);
+#else
+static inline int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible) { return 0; }
+#endif
+
+/**
+ *     vga_get_interruptible
+ *
+ *     Shortcut to vga_get
+ */
+
+static inline int vga_get_interruptible(struct pci_dev *pdev,
+					unsigned int rsrc)
+{
+       return vga_get(pdev, rsrc, 1);
+}
+
+/**
+ *     vga_get_uninterruptible
+ *
+ *     Shortcut to vga_get
+ */
+
+static inline int vga_get_uninterruptible(struct pci_dev *pdev,
+					  unsigned int rsrc)
+{
+       return vga_get(pdev, rsrc, 0);
+}
+
+/**
+ *     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
+ */
+
+#if defined(CONFIG_VGA_ARB)
+extern int vga_tryget(struct pci_dev *pdev, unsigned int rsrc);
+#else
+static inline int vga_tryget(struct pci_dev *pdev, unsigned int rsrc) { return 0; }
+#endif
+
+/**
+ *     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 function 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.
+ */
+
+#if defined(CONFIG_VGA_ARB)
+extern void vga_put(struct pci_dev *pdev, unsigned int rsrc);
+#else
+#define vga_put(pdev, rsrc)
+#endif
+
+
+/**
+ *     vga_default_device
+ *
+ *     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()...
+ */
+
+#ifdef CONFIG_VGA_ARB
+extern struct pci_dev *vga_default_device(void);
+extern void vga_set_default_device(struct pci_dev *pdev);
+#else
+static inline struct pci_dev *vga_default_device(void) { return NULL; };
+static inline void vga_set_default_device(struct pci_dev *pdev) { };
+#endif
+
+/**
+ *     vga_conflicts
+ *
+ *     Architectures should define this if they have several
+ *     independent PCI domains that can afford concurrent VGA
+ *     decoding
+ */
+
+#ifndef __ARCH_HAS_VGA_CONFLICT
+static inline int vga_conflicts(struct pci_dev *p1, struct pci_dev *p2)
+{
+       return 1;
+}
+#endif
+
+/**
+ *	vga_client_register
+ *
+ *	@pdev: pci device of the VGA client
+ *	@cookie: client cookie to be used in callbacks
+ *	@irq_set_state: irq state change callback
+ *	@set_vga_decode: vga decode change callback
+ *
+ * 	return value: 0 on success, -1 on failure
+ * 	Register a client with the VGA arbitration logic
+ *
+ *	Clients have two callback mechanisms they can use.
+ *	irq enable/disable callback -
+ *		If a client can't disable its GPUs VGA resources, then we
+ *		need to be able to ask it to turn off its irqs when we
+ *		turn off its mem and io decoding.
+ *	set_vga_decode
+ *		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.
+ * They driver will get a callback when VGA arbitration is first used
+ * by userspace since we some older X servers have issues.
+ */
+#if defined(CONFIG_VGA_ARB)
+int vga_client_register(struct pci_dev *pdev, void *cookie,
+			void (*irq_set_state)(void *cookie, bool state),
+			unsigned int (*set_vga_decode)(void *cookie, bool state));
+#else
+static inline int vga_client_register(struct pci_dev *pdev, void *cookie,
+				      void (*irq_set_state)(void *cookie, bool state),
+				      unsigned int (*set_vga_decode)(void *cookie, bool state))
+{
+	return 0;
+}
+#endif
+
+#endif /* LINUX_VGA_H */
-- 
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