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 _LINUXKPI_LINUX_VGA_H_
32 #define _LINUXKPI_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 #if defined(CONFIG_VGA_ARB)
69 extern void vga_set_legacy_decoding(struct pci_dev *pdev,
70 unsigned int decodes);
71 #else
vga_set_legacy_decoding(struct pci_dev * pdev,unsigned int decodes)72 static inline void vga_set_legacy_decoding(struct pci_dev *pdev,
73 unsigned int decodes) { };
74 #endif
75
76 /**
77 * vga_get - acquire & locks VGA resources
78 *
79 * @pdev: pci device of the VGA card or NULL for the system default
80 * @rsrc: bit mask of resources to acquire and lock
81 * @interruptible: blocking should be interruptible by signals ?
82 *
83 * This function acquires VGA resources for the given
84 * card and mark those resources locked. If the resource requested
85 * are "normal" (and not legacy) resources, the arbiter will first check
86 * whether the card is doing legacy decoding for that type of resource. If
87 * yes, the lock is "converted" into a legacy resource lock.
88 * The arbiter will first look for all VGA cards that might conflict
89 * and disable their IOs and/or Memory access, including VGA forwarding
90 * on P2P bridges if necessary, so that the requested resources can
91 * be used. Then, the card is marked as locking these resources and
92 * the IO and/or Memory accesse are enabled on the card (including
93 * VGA forwarding on parent P2P bridges if any).
94 * This function will block if some conflicting card is already locking
95 * one of the required resources (or any resource on a different bus
96 * segment, since P2P bridges don't differenciate VGA memory and IO
97 * afaik). You can indicate whether this blocking should be interruptible
98 * by a signal (for userland interface) or not.
99 * Must not be called at interrupt time or in atomic context.
100 * If the card already owns the resources, the function succeeds.
101 * Nested calls are supported (a per-resource counter is maintained)
102 */
103
104 #if defined(CONFIG_VGA_ARB)
105 extern int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible);
106 #else
vga_get(struct pci_dev * pdev,unsigned int rsrc,int interruptible)107 static inline int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible) { return 0; }
108 #endif
109
110 /**
111 * vga_get_interruptible
112 *
113 * Shortcut to vga_get
114 */
115
vga_get_interruptible(struct pci_dev * pdev,unsigned int rsrc)116 static inline int vga_get_interruptible(struct pci_dev *pdev,
117 unsigned int rsrc)
118 {
119 return vga_get(pdev, rsrc, 1);
120 }
121
122 /**
123 * vga_get_uninterruptible
124 *
125 * Shortcut to vga_get
126 */
127
vga_get_uninterruptible(struct pci_dev * pdev,unsigned int rsrc)128 static inline int vga_get_uninterruptible(struct pci_dev *pdev,
129 unsigned int rsrc)
130 {
131 return vga_get(pdev, rsrc, 0);
132 }
133
134 /**
135 * vga_tryget - try to acquire & lock legacy VGA resources
136 *
137 * @pdev: pci devivce of VGA card or NULL for system default
138 * @rsrc: bit mask of resources to acquire and lock
139 *
140 * This function performs the same operation as vga_get(), but
141 * will return an error (-EBUSY) instead of blocking if the resources
142 * are already locked by another card. It can be called in any context
143 */
144
145 #if defined(CONFIG_VGA_ARB)
146 extern int vga_tryget(struct pci_dev *pdev, unsigned int rsrc);
147 #else
vga_tryget(struct pci_dev * pdev,unsigned int rsrc)148 static inline int vga_tryget(struct pci_dev *pdev, unsigned int rsrc) { return 0; }
149 #endif
150
151 /**
152 * vga_put - release lock on legacy VGA resources
153 *
154 * @pdev: pci device of VGA card or NULL for system default
155 * @rsrc: but mask of resource to release
156 *
157 * This function releases resources previously locked by vga_get()
158 * or vga_tryget(). The resources aren't disabled right away, so
159 * that a subsequence vga_get() on the same card will succeed
160 * immediately. Resources have a counter, so locks are only
161 * released if the counter reaches 0.
162 */
163
164 #if defined(CONFIG_VGA_ARB)
165 extern void vga_put(struct pci_dev *pdev, unsigned int rsrc);
166 #else
167 #define vga_put(pdev, rsrc)
168 #endif
169
170
171 /**
172 * vga_default_device
173 *
174 * This can be defined by the platform. The default implementation
175 * is rather dumb and will probably only work properly on single
176 * vga card setups and/or x86 platforms.
177 *
178 * If your VGA default device is not PCI, you'll have to return
179 * NULL here. In this case, I assume it will not conflict with
180 * any PCI card. If this is not true, I'll have to define two archs
181 * hooks for enabling/disabling the VGA default device if that is
182 * possible. This may be a problem with real _ISA_ VGA cards, in
183 * addition to a PCI one. I don't know at this point how to deal
184 * with that card. Can theirs IOs be disabled at all ? If not, then
185 * I suppose it's a matter of having the proper arch hook telling
186 * us about it, so we basically never allow anybody to succeed a
187 * vga_get()...
188 */
189
190 #ifdef CONFIG_VGA_ARB
191 extern struct pci_dev *vga_default_device(void);
192 extern void vga_set_default_device(struct pci_dev *pdev);
193 #else
vga_default_device(void)194 static inline struct pci_dev *vga_default_device(void) { return NULL; };
vga_set_default_device(struct pci_dev * pdev)195 static inline void vga_set_default_device(struct pci_dev *pdev) { };
196 #endif
197
198 /**
199 * vga_conflicts
200 *
201 * Architectures should define this if they have several
202 * independent PCI domains that can afford concurrent VGA
203 * decoding
204 */
205
206 #ifndef __ARCH_HAS_VGA_CONFLICT
vga_conflicts(struct pci_dev * p1,struct pci_dev * p2)207 static inline int vga_conflicts(struct pci_dev *p1, struct pci_dev *p2)
208 {
209 return 1;
210 }
211 #endif
212
213 /**
214 * vga_client_register
215 *
216 * @pdev: pci device of the VGA client
217 * @cookie: client cookie to be used in callbacks
218 * @irq_set_state: irq state change callback
219 * @set_vga_decode: vga decode change callback
220 *
221 * return value: 0 on success, -1 on failure
222 * Register a client with the VGA arbitration logic
223 *
224 * Clients have two callback mechanisms they can use.
225 * irq enable/disable callback -
226 * If a client can't disable its GPUs VGA resources, then we
227 * need to be able to ask it to turn off its irqs when we
228 * turn off its mem and io decoding.
229 * set_vga_decode
230 * If a client can disable its GPU VGA resource, it will
231 * get a callback from this to set the encode/decode state
232 *
233 * Rationale: we cannot disable VGA decode resources unconditionally
234 * some single GPU laptops seem to require ACPI or BIOS access to the
235 * VGA registers to control things like backlights etc.
236 * Hopefully newer multi-GPU laptops do something saner, and desktops
237 * won't have any special ACPI for this.
238 * They driver will get a callback when VGA arbitration is first used
239 * by userspace since we some older X servers have issues.
240 */
241 #if defined(CONFIG_VGA_ARB)
242 #if defined(LINUXKPI_VERSION) && LINUXKPI_VERSION >= 51501
243 int vga_client_register(struct pci_dev *pdev,
244 unsigned int (*set_vga_decode)(struct pci_dev *pdev, bool state));
245 #elif defined(LINUXKPI_VERSION) && LINUXKPI_VERSION >= 51500
246 int vga_client_register(struct pci_dev *pdev, void *cookie,
247 unsigned int (*set_vga_decode)(void *cookie, bool state));
248 #else
249 int vga_client_register(struct pci_dev *pdev, void *cookie,
250 void (*irq_set_state)(void *cookie, bool state),
251 unsigned int (*set_vga_decode)(void *cookie, bool state));
252 #endif
253 #else
254 #if defined(LINUXKPI_VERSION) && LINUXKPI_VERSION >= 51501
vga_client_register(struct pci_dev * pdev,unsigned int (* set_vga_decode)(struct pci_dev * pdev,bool state))255 static inline int vga_client_register(struct pci_dev *pdev,
256 unsigned int (*set_vga_decode)(struct pci_dev *pdev, bool state))
257 #elif defined(LINUXKPI_VERSION) && LINUXKPI_VERSION >= 51500
258 static inline int vga_client_register(struct pci_dev *pdev, void *cookie,
259 unsigned int (*set_vga_decode)(void *cookie, bool state))
260 #else
261 static inline int vga_client_register(struct pci_dev *pdev, void *cookie,
262 void (*irq_set_state)(void *cookie, bool state),
263 unsigned int (*set_vga_decode)(void *cookie, bool state))
264 #endif
265 {
266 return 0;
267 }
268
vga_client_unregister(struct pci_dev * pdev)269 static inline int vga_client_unregister(struct pci_dev *pdev)
270 {
271 #if defined(LINUXKPI_VERSION) && LINUXKPI_VERSION >= 51501
272 return (vga_client_register(NULL, NULL));
273 #elif defined(LINUXKPI_VERSION) && LINUXKPI_VERSION >= 51500
274 return (vga_client_register(NULL, NULL, NULL));
275 #else
276 return (vga_client_register(NULL, NULL, NULL, NULL));
277 #endif
278 }
279 #endif
280
281 #endif /* _LINUXKPI_LINUX_VGA_H_ */
282