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1 | /* |
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. |
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> |
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 | * |
29 | */ |
30 | |
31 | #ifndef LINUX_VGA_H |
32 | #define LINUX_VGA_H |
33 | |
34 | #include <video/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 | struct pci_dev; |
52 | |
53 | /* For use by clients */ |
54 | |
55 | /** |
56 | * vga_set_legacy_decoding |
57 | * |
58 | * @pdev: pci device of the VGA card |
59 | * @decodes: bit mask of what legacy regions the card decodes |
60 | * |
61 | * Indicates to the arbiter if the card decodes legacy VGA IOs, |
62 | * legacy VGA Memory, both, or none. All cards default to both, |
63 | * the card driver (fbdev for example) should tell the arbiter |
64 | * if it has disabled legacy decoding, so the card can be left |
65 | * out of the arbitration process (and can be safe to take |
66 | * interrupts at any time. |
67 | */ |
68 | extern void vga_set_legacy_decoding(struct pci_dev *pdev, |
69 | unsigned int decodes); |
70 | |
71 | /** |
72 | * vga_get - acquire & locks VGA resources |
73 | * |
74 | * @pdev: pci device of the VGA card or NULL for the system default |
75 | * @rsrc: bit mask of resources to acquire and lock |
76 | * @interruptible: blocking should be interruptible by signals ? |
77 | * |
78 | * This function acquires VGA resources for the given |
79 | * card and mark those resources locked. If the resource requested |
80 | * are "normal" (and not legacy) resources, the arbiter will first check |
81 | * whether the card is doing legacy decoding for that type of resource. If |
82 | * yes, the lock is "converted" into a legacy resource lock. |
83 | * The arbiter will first look for all VGA cards that might conflict |
84 | * and disable their IOs and/or Memory access, including VGA forwarding |
85 | * on P2P bridges if necessary, so that the requested resources can |
86 | * be used. Then, the card is marked as locking these resources and |
87 | * the IO and/or Memory accesse are enabled on the card (including |
88 | * VGA forwarding on parent P2P bridges if any). |
89 | * This function will block if some conflicting card is already locking |
90 | * one of the required resources (or any resource on a different bus |
91 | * segment, since P2P bridges don't differenciate VGA memory and IO |
92 | * afaik). You can indicate whether this blocking should be interruptible |
93 | * by a signal (for userland interface) or not. |
94 | * Must not be called at interrupt time or in atomic context. |
95 | * If the card already owns the resources, the function succeeds. |
96 | * Nested calls are supported (a per-resource counter is maintained) |
97 | */ |
98 | |
99 | #if defined(CONFIG_VGA_ARB) |
100 | extern int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible); |
101 | #else |
102 | static inline int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible) { return 0; } |
103 | #endif |
104 | |
105 | /** |
106 | * vga_get_interruptible |
107 | * |
108 | * Shortcut to vga_get |
109 | */ |
110 | |
111 | static inline int vga_get_interruptible(struct pci_dev *pdev, |
112 | unsigned int rsrc) |
113 | { |
114 | return vga_get(pdev, rsrc, 1); |
115 | } |
116 | |
117 | /** |
118 | * vga_get_uninterruptible |
119 | * |
120 | * Shortcut to vga_get |
121 | */ |
122 | |
123 | static inline int vga_get_uninterruptible(struct pci_dev *pdev, |
124 | unsigned int rsrc) |
125 | { |
126 | return vga_get(pdev, rsrc, 0); |
127 | } |
128 | |
129 | /** |
130 | * vga_tryget - try to acquire & lock legacy VGA resources |
131 | * |
132 | * @pdev: pci devivce of VGA card or NULL for system default |
133 | * @rsrc: bit mask of resources to acquire and lock |
134 | * |
135 | * This function performs the same operation as vga_get(), but |
136 | * will return an error (-EBUSY) instead of blocking if the resources |
137 | * are already locked by another card. It can be called in any context |
138 | */ |
139 | |
140 | #if defined(CONFIG_VGA_ARB) |
141 | extern int vga_tryget(struct pci_dev *pdev, unsigned int rsrc); |
142 | #else |
143 | static inline int vga_tryget(struct pci_dev *pdev, unsigned int rsrc) { return 0; } |
144 | #endif |
145 | |
146 | /** |
147 | * vga_put - release lock on legacy VGA resources |
148 | * |
149 | * @pdev: pci device of VGA card or NULL for system default |
150 | * @rsrc: but mask of resource to release |
151 | * |
152 | * This function releases resources previously locked by vga_get() |
153 | * or vga_tryget(). The resources aren't disabled right away, so |
154 | * that a subsequence vga_get() on the same card will succeed |
155 | * immediately. Resources have a counter, so locks are only |
156 | * released if the counter reaches 0. |
157 | */ |
158 | |
159 | #if defined(CONFIG_VGA_ARB) |
160 | extern void vga_put(struct pci_dev *pdev, unsigned int rsrc); |
161 | #else |
162 | #define vga_put(pdev, rsrc) |
163 | #endif |
164 | |
165 | |
166 | /** |
167 | * vga_default_device |
168 | * |
169 | * This can be defined by the platform. The default implementation |
170 | * is rather dumb and will probably only work properly on single |
171 | * vga card setups and/or x86 platforms. |
172 | * |
173 | * If your VGA default device is not PCI, you'll have to return |
174 | * NULL here. In this case, I assume it will not conflict with |
175 | * any PCI card. If this is not true, I'll have to define two archs |
176 | * hooks for enabling/disabling the VGA default device if that is |
177 | * possible. This may be a problem with real _ISA_ VGA cards, in |
178 | * addition to a PCI one. I don't know at this point how to deal |
179 | * with that card. Can theirs IOs be disabled at all ? If not, then |
180 | * I suppose it's a matter of having the proper arch hook telling |
181 | * us about it, so we basically never allow anybody to succeed a |
182 | * vga_get()... |
183 | */ |
184 | |
185 | #ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE |
186 | #ifdef CONFIG_VGA_ARB |
187 | extern struct pci_dev *vga_default_device(void); |
188 | extern void vga_set_default_device(struct pci_dev *pdev); |
189 | #else |
190 | static inline struct pci_dev *vga_default_device(void) { return NULL; }; |
191 | static inline void vga_set_default_device(struct pci_dev *pdev) { }; |
192 | #endif |
193 | #endif |
194 | |
195 | /** |
196 | * vga_conflicts |
197 | * |
198 | * Architectures should define this if they have several |
199 | * independent PCI domains that can afford concurrent VGA |
200 | * decoding |
201 | */ |
202 | |
203 | #ifndef __ARCH_HAS_VGA_CONFLICT |
204 | static inline int vga_conflicts(struct pci_dev *p1, struct pci_dev *p2) |
205 | { |
206 | return 1; |
207 | } |
208 | #endif |
209 | |
210 | /** |
211 | * vga_client_register |
212 | * |
213 | * @pdev: pci device of the VGA client |
214 | * @cookie: client cookie to be used in callbacks |
215 | * @irq_set_state: irq state change callback |
216 | * @set_vga_decode: vga decode change callback |
217 | * |
218 | * return value: 0 on success, -1 on failure |
219 | * Register a client with the VGA arbitration logic |
220 | * |
221 | * Clients have two callback mechanisms they can use. |
222 | * irq enable/disable callback - |
223 | * If a client can't disable its GPUs VGA resources, then we |
224 | * need to be able to ask it to turn off its irqs when we |
225 | * turn off its mem and io decoding. |
226 | * set_vga_decode |
227 | * If a client can disable its GPU VGA resource, it will |
228 | * get a callback from this to set the encode/decode state |
229 | * |
230 | * Rationale: we cannot disable VGA decode resources unconditionally |
231 | * some single GPU laptops seem to require ACPI or BIOS access to the |
232 | * VGA registers to control things like backlights etc. |
233 | * Hopefully newer multi-GPU laptops do something saner, and desktops |
234 | * won't have any special ACPI for this. |
235 | * They driver will get a callback when VGA arbitration is first used |
236 | * by userspace since we some older X servers have issues. |
237 | */ |
238 | #if defined(CONFIG_VGA_ARB) |
239 | int vga_client_register(struct pci_dev *pdev, void *cookie, |
240 | void (*irq_set_state)(void *cookie, bool state), |
241 | unsigned int (*set_vga_decode)(void *cookie, bool state)); |
242 | #else |
243 | static inline int vga_client_register(struct pci_dev *pdev, void *cookie, |
244 | void (*irq_set_state)(void *cookie, bool state), |
245 | unsigned int (*set_vga_decode)(void *cookie, bool state)) |
246 | { |
247 | return 0; |
248 | } |
249 | #endif |
250 | |
251 | #endif /* LINUX_VGA_H */ |
252 |
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