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Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +10001/*
Jesse Barnese2d43042009-09-17 09:40:31 -07002 * The VGA aribiter manages VGA space routing and VGA resource decode to
3 * allow multiple VGA devices to be used in a system in a safe way.
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +10004 *
5 * (C) Copyright 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>
6 * (C) Copyright 2007 Paulo R. Zanoni <przanoni@gmail.com>
7 * (C) Copyright 2007, 2009 Tiago Vignatti <vignatti@freedesktop.org>
Tiago Vignattic0db9cb2010-05-24 18:24:31 +03008 *
9 * Permission is hereby granted, free of charge, to any person obtaining a
10 * copy of this software and associated documentation files (the "Software"),
11 * to deal in the Software without restriction, including without limitation
12 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
13 * and/or sell copies of the Software, and to permit persons to whom the
14 * Software is furnished to do so, subject to the following conditions:
15 *
16 * The above copyright notice and this permission notice (including the next
17 * paragraph) shall be included in all copies or substantial portions of the
18 * Software.
19 *
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
23 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
24 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
25 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
26 * DEALINGS
27 * IN THE SOFTWARE.
28 *
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +100029 */
30
31#ifndef LINUX_VGA_H
Doug Goldsteina6a1a092010-07-20 15:22:25 -070032#define LINUX_VGA_H
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +100033
34#include <asm/vga.h>
35
36/* Legacy VGA regions */
37#define VGA_RSRC_NONE 0x00
38#define VGA_RSRC_LEGACY_IO 0x01
39#define VGA_RSRC_LEGACY_MEM 0x02
40#define VGA_RSRC_LEGACY_MASK (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM)
41/* Non-legacy access */
42#define VGA_RSRC_NORMAL_IO 0x04
43#define VGA_RSRC_NORMAL_MEM 0x08
44
45/* Passing that instead of a pci_dev to use the system "default"
46 * device, that is the one used by vgacon. Archs will probably
47 * have to provide their own vga_default_device();
48 */
49#define VGA_DEFAULT_DEVICE (NULL)
50
51/* For use by clients */
52
53/**
54 * vga_set_legacy_decoding
55 *
56 * @pdev: pci device of the VGA card
57 * @decodes: bit mask of what legacy regions the card decodes
58 *
59 * Indicates to the arbiter if the card decodes legacy VGA IOs,
60 * legacy VGA Memory, both, or none. All cards default to both,
61 * the card driver (fbdev for example) should tell the arbiter
62 * if it has disabled legacy decoding, so the card can be left
63 * out of the arbitration process (and can be safe to take
64 * interrupts at any time.
65 */
66extern void vga_set_legacy_decoding(struct pci_dev *pdev,
Ingo Molnar7c329282009-09-23 09:52:18 +100067 unsigned int decodes);
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +100068
69/**
70 * vga_get - acquire & locks VGA resources
71 *
Dave Airlie6ac3bd52009-08-19 15:21:57 +100072 * @pdev: pci device of the VGA card or NULL for the system default
73 * @rsrc: bit mask of resources to acquire and lock
74 * @interruptible: blocking should be interruptible by signals ?
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +100075 *
76 * This function acquires VGA resources for the given
77 * card and mark those resources locked. If the resource requested
78 * are "normal" (and not legacy) resources, the arbiter will first check
79 * wether the card is doing legacy decoding for that type of resource. If
80 * yes, the lock is "converted" into a legacy resource lock.
81 * The arbiter will first look for all VGA cards that might conflict
82 * and disable their IOs and/or Memory access, inlcuding VGA forwarding
83 * on P2P bridges if necessary, so that the requested resources can
84 * be used. Then, the card is marked as locking these resources and
85 * the IO and/or Memory accesse are enabled on the card (including
86 * VGA forwarding on parent P2P bridges if any).
87 * This function will block if some conflicting card is already locking
88 * one of the required resources (or any resource on a different bus
89 * segment, since P2P bridges don't differenciate VGA memory and IO
90 * afaik). You can indicate wether this blocking should be interruptible
91 * by a signal (for userland interface) or not.
92 * Must not be called at interrupt time or in atomic context.
93 * If the card already owns the resources, the function succeeds.
94 * Nested calls are supported (a per-resource counter is maintained)
95 */
96
97extern int vga_get(struct pci_dev *pdev, unsigned int rsrc,
98 int interruptible);
99
100/**
101 * vga_get_interruptible
102 *
103 * Shortcut to vga_get
104 */
105
106static inline int vga_get_interruptible(struct pci_dev *pdev,
Dave Airlie6ac3bd52009-08-19 15:21:57 +1000107 unsigned int rsrc)
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +1000108{
109 return vga_get(pdev, rsrc, 1);
110}
111
112/**
Dave Airlie6ac3bd52009-08-19 15:21:57 +1000113 * vga_get_uninterruptible
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +1000114 *
115 * Shortcut to vga_get
116 */
117
118static inline int vga_get_uninterruptible(struct pci_dev *pdev,
Dave Airlie6ac3bd52009-08-19 15:21:57 +1000119 unsigned int rsrc)
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +1000120{
121 return vga_get(pdev, rsrc, 0);
122}
123
124/**
125 * vga_tryget - try to acquire & lock legacy VGA resources
126 *
127 * @pdev: pci devivce of VGA card or NULL for system default
128 * @rsrc: bit mask of resources to acquire and lock
129 *
130 * This function performs the same operation as vga_get(), but
131 * will return an error (-EBUSY) instead of blocking if the resources
132 * are already locked by another card. It can be called in any context
133 */
134
135extern int vga_tryget(struct pci_dev *pdev, unsigned int rsrc);
136
137/**
138 * vga_put - release lock on legacy VGA resources
139 *
140 * @pdev: pci device of VGA card or NULL for system default
141 * @rsrc: but mask of resource to release
142 *
143 * This function releases resources previously locked by vga_get()
144 * or vga_tryget(). The resources aren't disabled right away, so
145 * that a subsequence vga_get() on the same card will succeed
146 * immediately. Resources have a counter, so locks are only
147 * released if the counter reaches 0.
148 */
149
150extern void vga_put(struct pci_dev *pdev, unsigned int rsrc);
151
152
153/**
154 * vga_default_device
155 *
156 * This can be defined by the platform. The default implementation
157 * is rather dumb and will probably only work properly on single
158 * vga card setups and/or x86 platforms.
159 *
160 * If your VGA default device is not PCI, you'll have to return
161 * NULL here. In this case, I assume it will not conflict with
162 * any PCI card. If this is not true, I'll have to define two archs
163 * hooks for enabling/disabling the VGA default device if that is
164 * possible. This may be a problem with real _ISA_ VGA cards, in
165 * addition to a PCI one. I don't know at this point how to deal
166 * with that card. Can theirs IOs be disabled at all ? If not, then
167 * I suppose it's a matter of having the proper arch hook telling
168 * us about it, so we basically never allow anybody to succeed a
169 * vga_get()...
170 */
171
172#ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE
173extern struct pci_dev *vga_default_device(void);
174#endif
175
176/**
177 * vga_conflicts
178 *
179 * Architectures should define this if they have several
180 * independant PCI domains that can afford concurrent VGA
181 * decoding
182 */
183
184#ifndef __ARCH_HAS_VGA_CONFLICT
185static inline int vga_conflicts(struct pci_dev *p1, struct pci_dev *p2)
186{
187 return 1;
188}
189#endif
190
Dave Airlie6ac3bd52009-08-19 15:21:57 +1000191/**
192 * vga_client_register
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +1000193 *
Dave Airlie6ac3bd52009-08-19 15:21:57 +1000194 * @pdev: pci device of the VGA client
195 * @cookie: client cookie to be used in callbacks
196 * @irq_set_state: irq state change callback
197 * @set_vga_decode: vga decode change callback
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +1000198 *
Dave Airlie6ac3bd52009-08-19 15:21:57 +1000199 * return value: 0 on success, -1 on failure
200 * Register a client with the VGA arbitration logic
201 *
202 * Clients have two callback mechanisms they can use.
203 * irq enable/disable callback -
204 * If a client can't disable its GPUs VGA resources, then we
205 * need to be able to ask it to turn off its irqs when we
206 * turn off its mem and io decoding.
207 * set_vga_decode
208 * If a client can disable its GPU VGA resource, it will
209 * get a callback from this to set the encode/decode state
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +1000210 *
211 * Rationale: we cannot disable VGA decode resources unconditionally
212 * some single GPU laptops seem to require ACPI or BIOS access to the
213 * VGA registers to control things like backlights etc.
214 * Hopefully newer multi-GPU laptops do something saner, and desktops
215 * won't have any special ACPI for this.
Dave Airlie6ac3bd52009-08-19 15:21:57 +1000216 * They driver will get a callback when VGA arbitration is first used
217 * by userspace since we some older X servers have issues.
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +1000218 */
Ingo Molnar7c329282009-09-23 09:52:18 +1000219#if defined(CONFIG_VGA_ARB)
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +1000220int vga_client_register(struct pci_dev *pdev, void *cookie,
221 void (*irq_set_state)(void *cookie, bool state),
222 unsigned int (*set_vga_decode)(void *cookie, bool state));
Ingo Molnar7c329282009-09-23 09:52:18 +1000223#else
224static inline int vga_client_register(struct pci_dev *pdev, void *cookie,
225 void (*irq_set_state)(void *cookie, bool state),
226 unsigned int (*set_vga_decode)(void *cookie, bool state))
227{
228 return 0;
229}
230#endif
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +1000231
232#endif /* LINUX_VGA_H */