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deb2d2ec | 1 | /* |
e2d4304b JB |
2 | * 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. | |
deb2d2ec BH |
4 | * |
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> | |
c0db9cbc TV |
8 | * |
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 | * | |
deb2d2ec BH |
29 | */ |
30 | ||
31 | #ifndef LINUX_VGA_H | |
a6a1a095 | 32 | #define LINUX_VGA_H |
deb2d2ec BH |
33 | |
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 | */ | |
66 | extern void vga_set_legacy_decoding(struct pci_dev *pdev, | |
7c329288 | 67 | unsigned int decodes); |
deb2d2ec BH |
68 | |
69 | /** | |
70 | * vga_get - acquire & locks VGA resources | |
71 | * | |
6ac3bd52 DA |
72 | * @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 ? | |
deb2d2ec BH |
75 | * |
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 | ||
97 | extern 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 | ||
106 | static inline int vga_get_interruptible(struct pci_dev *pdev, | |
6ac3bd52 | 107 | unsigned int rsrc) |
deb2d2ec BH |
108 | { |
109 | return vga_get(pdev, rsrc, 1); | |
110 | } | |
111 | ||
112 | /** | |
6ac3bd52 | 113 | * vga_get_uninterruptible |
deb2d2ec BH |
114 | * |
115 | * Shortcut to vga_get | |
116 | */ | |
117 | ||
118 | static inline int vga_get_uninterruptible(struct pci_dev *pdev, | |
6ac3bd52 | 119 | unsigned int rsrc) |
deb2d2ec BH |
120 | { |
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 | ||
135 | extern 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 | ||
150 | extern 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 | |
173 | extern 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 | |
185 | static inline int vga_conflicts(struct pci_dev *p1, struct pci_dev *p2) | |
186 | { | |
187 | return 1; | |
188 | } | |
189 | #endif | |
190 | ||
6ac3bd52 DA |
191 | /** |
192 | * vga_client_register | |
193 | * | |
194 | * @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 | |
198 | * | |
199 | * 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 | |
deb2d2ec BH |
210 | * |
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. | |
6ac3bd52 DA |
216 | * They driver will get a callback when VGA arbitration is first used |
217 | * by userspace since we some older X servers have issues. | |
deb2d2ec | 218 | */ |
7c329288 | 219 | #if defined(CONFIG_VGA_ARB) |
deb2d2ec BH |
220 | int 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)); | |
7c329288 IM |
223 | #else |
224 | static 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 | |
deb2d2ec BH |
231 | |
232 | #endif /* LINUX_VGA_H */ |