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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> | |
8 | */ | |
9 | ||
10 | #ifndef LINUX_VGA_H | |
11 | ||
12 | #include <asm/vga.h> | |
13 | ||
14 | /* Legacy VGA regions */ | |
15 | #define VGA_RSRC_NONE 0x00 | |
16 | #define VGA_RSRC_LEGACY_IO 0x01 | |
17 | #define VGA_RSRC_LEGACY_MEM 0x02 | |
18 | #define VGA_RSRC_LEGACY_MASK (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM) | |
19 | /* Non-legacy access */ | |
20 | #define VGA_RSRC_NORMAL_IO 0x04 | |
21 | #define VGA_RSRC_NORMAL_MEM 0x08 | |
22 | ||
23 | /* Passing that instead of a pci_dev to use the system "default" | |
24 | * device, that is the one used by vgacon. Archs will probably | |
25 | * have to provide their own vga_default_device(); | |
26 | */ | |
27 | #define VGA_DEFAULT_DEVICE (NULL) | |
28 | ||
29 | /* For use by clients */ | |
30 | ||
31 | /** | |
32 | * vga_set_legacy_decoding | |
33 | * | |
34 | * @pdev: pci device of the VGA card | |
35 | * @decodes: bit mask of what legacy regions the card decodes | |
36 | * | |
37 | * Indicates to the arbiter if the card decodes legacy VGA IOs, | |
38 | * legacy VGA Memory, both, or none. All cards default to both, | |
39 | * the card driver (fbdev for example) should tell the arbiter | |
40 | * if it has disabled legacy decoding, so the card can be left | |
41 | * out of the arbitration process (and can be safe to take | |
42 | * interrupts at any time. | |
43 | */ | |
44 | extern void vga_set_legacy_decoding(struct pci_dev *pdev, | |
7c329288 | 45 | unsigned int decodes); |
deb2d2ec BH |
46 | |
47 | /** | |
48 | * vga_get - acquire & locks VGA resources | |
49 | * | |
6ac3bd52 DA |
50 | * @pdev: pci device of the VGA card or NULL for the system default |
51 | * @rsrc: bit mask of resources to acquire and lock | |
52 | * @interruptible: blocking should be interruptible by signals ? | |
deb2d2ec BH |
53 | * |
54 | * This function acquires VGA resources for the given | |
55 | * card and mark those resources locked. If the resource requested | |
56 | * are "normal" (and not legacy) resources, the arbiter will first check | |
57 | * wether the card is doing legacy decoding for that type of resource. If | |
58 | * yes, the lock is "converted" into a legacy resource lock. | |
59 | * The arbiter will first look for all VGA cards that might conflict | |
60 | * and disable their IOs and/or Memory access, inlcuding VGA forwarding | |
61 | * on P2P bridges if necessary, so that the requested resources can | |
62 | * be used. Then, the card is marked as locking these resources and | |
63 | * the IO and/or Memory accesse are enabled on the card (including | |
64 | * VGA forwarding on parent P2P bridges if any). | |
65 | * This function will block if some conflicting card is already locking | |
66 | * one of the required resources (or any resource on a different bus | |
67 | * segment, since P2P bridges don't differenciate VGA memory and IO | |
68 | * afaik). You can indicate wether this blocking should be interruptible | |
69 | * by a signal (for userland interface) or not. | |
70 | * Must not be called at interrupt time or in atomic context. | |
71 | * If the card already owns the resources, the function succeeds. | |
72 | * Nested calls are supported (a per-resource counter is maintained) | |
73 | */ | |
74 | ||
75 | extern int vga_get(struct pci_dev *pdev, unsigned int rsrc, | |
76 | int interruptible); | |
77 | ||
78 | /** | |
79 | * vga_get_interruptible | |
80 | * | |
81 | * Shortcut to vga_get | |
82 | */ | |
83 | ||
84 | static inline int vga_get_interruptible(struct pci_dev *pdev, | |
6ac3bd52 | 85 | unsigned int rsrc) |
deb2d2ec BH |
86 | { |
87 | return vga_get(pdev, rsrc, 1); | |
88 | } | |
89 | ||
90 | /** | |
6ac3bd52 | 91 | * vga_get_uninterruptible |
deb2d2ec BH |
92 | * |
93 | * Shortcut to vga_get | |
94 | */ | |
95 | ||
96 | static inline int vga_get_uninterruptible(struct pci_dev *pdev, | |
6ac3bd52 | 97 | unsigned int rsrc) |
deb2d2ec BH |
98 | { |
99 | return vga_get(pdev, rsrc, 0); | |
100 | } | |
101 | ||
102 | /** | |
103 | * vga_tryget - try to acquire & lock legacy VGA resources | |
104 | * | |
105 | * @pdev: pci devivce of VGA card or NULL for system default | |
106 | * @rsrc: bit mask of resources to acquire and lock | |
107 | * | |
108 | * This function performs the same operation as vga_get(), but | |
109 | * will return an error (-EBUSY) instead of blocking if the resources | |
110 | * are already locked by another card. It can be called in any context | |
111 | */ | |
112 | ||
113 | extern int vga_tryget(struct pci_dev *pdev, unsigned int rsrc); | |
114 | ||
115 | /** | |
116 | * vga_put - release lock on legacy VGA resources | |
117 | * | |
118 | * @pdev: pci device of VGA card or NULL for system default | |
119 | * @rsrc: but mask of resource to release | |
120 | * | |
121 | * This function releases resources previously locked by vga_get() | |
122 | * or vga_tryget(). The resources aren't disabled right away, so | |
123 | * that a subsequence vga_get() on the same card will succeed | |
124 | * immediately. Resources have a counter, so locks are only | |
125 | * released if the counter reaches 0. | |
126 | */ | |
127 | ||
128 | extern void vga_put(struct pci_dev *pdev, unsigned int rsrc); | |
129 | ||
130 | ||
131 | /** | |
132 | * vga_default_device | |
133 | * | |
134 | * This can be defined by the platform. The default implementation | |
135 | * is rather dumb and will probably only work properly on single | |
136 | * vga card setups and/or x86 platforms. | |
137 | * | |
138 | * If your VGA default device is not PCI, you'll have to return | |
139 | * NULL here. In this case, I assume it will not conflict with | |
140 | * any PCI card. If this is not true, I'll have to define two archs | |
141 | * hooks for enabling/disabling the VGA default device if that is | |
142 | * possible. This may be a problem with real _ISA_ VGA cards, in | |
143 | * addition to a PCI one. I don't know at this point how to deal | |
144 | * with that card. Can theirs IOs be disabled at all ? If not, then | |
145 | * I suppose it's a matter of having the proper arch hook telling | |
146 | * us about it, so we basically never allow anybody to succeed a | |
147 | * vga_get()... | |
148 | */ | |
149 | ||
150 | #ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE | |
151 | extern struct pci_dev *vga_default_device(void); | |
152 | #endif | |
153 | ||
154 | /** | |
155 | * vga_conflicts | |
156 | * | |
157 | * Architectures should define this if they have several | |
158 | * independant PCI domains that can afford concurrent VGA | |
159 | * decoding | |
160 | */ | |
161 | ||
162 | #ifndef __ARCH_HAS_VGA_CONFLICT | |
163 | static inline int vga_conflicts(struct pci_dev *p1, struct pci_dev *p2) | |
164 | { | |
165 | return 1; | |
166 | } | |
167 | #endif | |
168 | ||
6ac3bd52 DA |
169 | /** |
170 | * vga_client_register | |
171 | * | |
172 | * @pdev: pci device of the VGA client | |
173 | * @cookie: client cookie to be used in callbacks | |
174 | * @irq_set_state: irq state change callback | |
175 | * @set_vga_decode: vga decode change callback | |
176 | * | |
177 | * return value: 0 on success, -1 on failure | |
178 | * Register a client with the VGA arbitration logic | |
179 | * | |
180 | * Clients have two callback mechanisms they can use. | |
181 | * irq enable/disable callback - | |
182 | * If a client can't disable its GPUs VGA resources, then we | |
183 | * need to be able to ask it to turn off its irqs when we | |
184 | * turn off its mem and io decoding. | |
185 | * set_vga_decode | |
186 | * If a client can disable its GPU VGA resource, it will | |
187 | * get a callback from this to set the encode/decode state | |
deb2d2ec BH |
188 | * |
189 | * Rationale: we cannot disable VGA decode resources unconditionally | |
190 | * some single GPU laptops seem to require ACPI or BIOS access to the | |
191 | * VGA registers to control things like backlights etc. | |
192 | * Hopefully newer multi-GPU laptops do something saner, and desktops | |
193 | * won't have any special ACPI for this. | |
6ac3bd52 DA |
194 | * They driver will get a callback when VGA arbitration is first used |
195 | * by userspace since we some older X servers have issues. | |
deb2d2ec | 196 | */ |
7c329288 | 197 | #if defined(CONFIG_VGA_ARB) |
deb2d2ec BH |
198 | int vga_client_register(struct pci_dev *pdev, void *cookie, |
199 | void (*irq_set_state)(void *cookie, bool state), | |
200 | unsigned int (*set_vga_decode)(void *cookie, bool state)); | |
7c329288 IM |
201 | #else |
202 | static inline int vga_client_register(struct pci_dev *pdev, void *cookie, | |
203 | void (*irq_set_state)(void *cookie, bool state), | |
204 | unsigned int (*set_vga_decode)(void *cookie, bool state)) | |
205 | { | |
206 | return 0; | |
207 | } | |
208 | #endif | |
deb2d2ec BH |
209 | |
210 | #endif /* LINUX_VGA_H */ |