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1 /* SPDX-License-Identifier: MIT */
2 /*
3 * fbif.h -- Xen virtual frame buffer device
4 *
5 * Copyright (C) 2005 Anthony Liguori <aliguori@us.ibm.com>
6 * Copyright (C) 2006 Red Hat, Inc., Markus Armbruster <armbru@redhat.com>
7 */
8
9 #ifndef __XEN_PUBLIC_IO_FBIF_H__
10 #define __XEN_PUBLIC_IO_FBIF_H__
11
12 /* Out events (frontend -> backend) */
13
14 /*
15 * Out events may be sent only when requested by backend, and receipt
16 * of an unknown out event is an error.
17 */
18
19 /* Event type 1 currently not used */
20 /*
21 * Framebuffer update notification event
22 * Capable frontend sets feature-update in xenstore.
23 * Backend requests it by setting request-update in xenstore.
24 */
25 #define XENFB_TYPE_UPDATE 2
26
27 struct xenfb_update
28 {
29 uint8_t type; /* XENFB_TYPE_UPDATE */
30 int32_t x; /* source x */
31 int32_t y; /* source y */
32 int32_t width; /* rect width */
33 int32_t height; /* rect height */
34 };
35
36 /*
37 * Framebuffer resize notification event
38 * Capable backend sets feature-resize in xenstore.
39 */
40 #define XENFB_TYPE_RESIZE 3
41
42 struct xenfb_resize
43 {
44 uint8_t type; /* XENFB_TYPE_RESIZE */
45 int32_t width; /* width in pixels */
46 int32_t height; /* height in pixels */
47 int32_t stride; /* stride in bytes */
48 int32_t depth; /* depth in bits */
49 int32_t offset; /* offset of the framebuffer in bytes */
50 };
51
52 #define XENFB_OUT_EVENT_SIZE 40
53
54 union xenfb_out_event
55 {
56 uint8_t type;
57 struct xenfb_update update;
58 struct xenfb_resize resize;
59 char pad[XENFB_OUT_EVENT_SIZE];
60 };
61
62 /* In events (backend -> frontend) */
63
64 /*
65 * Frontends should ignore unknown in events.
66 */
67
68 /*
69 * Framebuffer refresh period advice
70 * Backend sends it to advise the frontend their preferred period of
71 * refresh. Frontends that keep the framebuffer constantly up-to-date
72 * just ignore it. Frontends that use the advice should immediately
73 * refresh the framebuffer (and send an update notification event if
74 * those have been requested), then use the update frequency to guide
75 * their periodical refreshs.
76 */
77 #define XENFB_TYPE_REFRESH_PERIOD 1
78 #define XENFB_NO_REFRESH 0
79
80 struct xenfb_refresh_period
81 {
82 uint8_t type; /* XENFB_TYPE_UPDATE_PERIOD */
83 uint32_t period; /* period of refresh, in ms,
84 * XENFB_NO_REFRESH if no refresh is needed */
85 };
86
87 #define XENFB_IN_EVENT_SIZE 40
88
89 union xenfb_in_event
90 {
91 uint8_t type;
92 struct xenfb_refresh_period refresh_period;
93 char pad[XENFB_IN_EVENT_SIZE];
94 };
95
96 /* shared page */
97
98 #define XENFB_IN_RING_SIZE 1024
99 #define XENFB_IN_RING_LEN (XENFB_IN_RING_SIZE / XENFB_IN_EVENT_SIZE)
100 #define XENFB_IN_RING_OFFS 1024
101 #define XENFB_IN_RING(page) \
102 ((union xenfb_in_event *)((char *)(page) + XENFB_IN_RING_OFFS))
103 #define XENFB_IN_RING_REF(page, idx) \
104 (XENFB_IN_RING((page))[(idx) % XENFB_IN_RING_LEN])
105
106 #define XENFB_OUT_RING_SIZE 2048
107 #define XENFB_OUT_RING_LEN (XENFB_OUT_RING_SIZE / XENFB_OUT_EVENT_SIZE)
108 #define XENFB_OUT_RING_OFFS (XENFB_IN_RING_OFFS + XENFB_IN_RING_SIZE)
109 #define XENFB_OUT_RING(page) \
110 ((union xenfb_out_event *)((char *)(page) + XENFB_OUT_RING_OFFS))
111 #define XENFB_OUT_RING_REF(page, idx) \
112 (XENFB_OUT_RING((page))[(idx) % XENFB_OUT_RING_LEN])
113
114 struct xenfb_page
115 {
116 uint32_t in_cons, in_prod;
117 uint32_t out_cons, out_prod;
118
119 int32_t width; /* the width of the framebuffer (in pixels) */
120 int32_t height; /* the height of the framebuffer (in pixels) */
121 uint32_t line_length; /* the length of a row of pixels (in bytes) */
122 uint32_t mem_length; /* the length of the framebuffer (in bytes) */
123 uint8_t depth; /* the depth of a pixel (in bits) */
124
125 /*
126 * Framebuffer page directory
127 *
128 * Each directory page holds PAGE_SIZE / sizeof(*pd)
129 * framebuffer pages, and can thus map up to PAGE_SIZE *
130 * PAGE_SIZE / sizeof(*pd) bytes. With PAGE_SIZE == 4096 and
131 * sizeof(unsigned long) == 4/8, that's 4 Megs 32 bit and 2 Megs
132 * 64 bit. 256 directories give enough room for a 512 Meg
133 * framebuffer with a max resolution of 12,800x10,240. Should
134 * be enough for a while with room leftover for expansion.
135 */
136 unsigned long pd[256];
137 };
138
139 /*
140 * Wart: xenkbd needs to know default resolution. Put it here until a
141 * better solution is found, but don't leak it to the backend.
142 */
143 #ifdef __KERNEL__
144 #define XENFB_WIDTH 800
145 #define XENFB_HEIGHT 600
146 #define XENFB_DEPTH 32
147 #endif
148
149 #endif
150
151 /*
152 * Local variables:
153 * mode: C
154 * c-file-style: "BSD"
155 * c-basic-offset: 4
156 * tab-width: 4
157 * indent-tabs-mode: nil
158 * End:
159 */