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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>
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 */
44extern void vga_set_legacy_decoding(struct pci_dev *pdev,
Ingo Molnar7c329282009-09-23 09:52:18 +100045 unsigned int decodes);
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +100046
47/**
48 * vga_get - acquire & locks VGA resources
49 *
Dave Airlie6ac3bd52009-08-19 15:21:57 +100050 * @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 ?
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +100053 *
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
75extern 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
84static inline int vga_get_interruptible(struct pci_dev *pdev,
Dave Airlie6ac3bd52009-08-19 15:21:57 +100085 unsigned int rsrc)
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +100086{
87 return vga_get(pdev, rsrc, 1);
88}
89
90/**
Dave Airlie6ac3bd52009-08-19 15:21:57 +100091 * vga_get_uninterruptible
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +100092 *
93 * Shortcut to vga_get
94 */
95
96static inline int vga_get_uninterruptible(struct pci_dev *pdev,
Dave Airlie6ac3bd52009-08-19 15:21:57 +100097 unsigned int rsrc)
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +100098{
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
113extern 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
128extern 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
151extern 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
163static inline int vga_conflicts(struct pci_dev *p1, struct pci_dev *p2)
164{
165 return 1;
166}
167#endif
168
Dave Airlie6ac3bd52009-08-19 15:21:57 +1000169/**
170 * vga_client_register
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +1000171 *
Dave Airlie6ac3bd52009-08-19 15:21:57 +1000172 * @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
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +1000176 *
Dave Airlie6ac3bd52009-08-19 15:21:57 +1000177 * 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
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +1000188 *
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.
Dave Airlie6ac3bd52009-08-19 15:21:57 +1000194 * They driver will get a callback when VGA arbitration is first used
195 * by userspace since we some older X servers have issues.
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +1000196 */
Ingo Molnar7c329282009-09-23 09:52:18 +1000197#if defined(CONFIG_VGA_ARB)
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +1000198int 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));
Ingo Molnar7c329282009-09-23 09:52:18 +1000201#else
202static 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
Benjamin Herrenschmidtdeb2d2e2009-08-11 15:52:06 +1000209
210#endif /* LINUX_VGA_H */