xref: /linux/include/xen/interface/io/fbif.h (revision 34f7c6e7d4396090692a09789db231e12cb4762b)
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 	uint8_t type;		/* XENFB_TYPE_UPDATE */
29 	int32_t x;		/* source x */
30 	int32_t y;		/* source y */
31 	int32_t width;		/* rect width */
32 	int32_t height;		/* rect height */
33 };
34 
35 /*
36  * Framebuffer resize notification event
37  * Capable backend sets feature-resize in xenstore.
38  */
39 #define XENFB_TYPE_RESIZE 3
40 
41 struct xenfb_resize {
42 	uint8_t type;		/* XENFB_TYPE_RESIZE */
43 	int32_t width;		/* width in pixels */
44 	int32_t height;		/* height in pixels */
45 	int32_t stride;		/* stride in bytes */
46 	int32_t depth;		/* depth in bits */
47 	int32_t offset;		/* start offset within framebuffer */
48 };
49 
50 #define XENFB_OUT_EVENT_SIZE 40
51 
52 union xenfb_out_event {
53 	uint8_t type;
54 	struct xenfb_update update;
55 	struct xenfb_resize resize;
56 	char pad[XENFB_OUT_EVENT_SIZE];
57 };
58 
59 /* In events (backend -> frontend) */
60 
61 /*
62  * Frontends should ignore unknown in events.
63  * No in events currently defined.
64  */
65 
66 #define XENFB_IN_EVENT_SIZE 40
67 
68 union xenfb_in_event {
69 	uint8_t type;
70 	char pad[XENFB_IN_EVENT_SIZE];
71 };
72 
73 /* shared page */
74 
75 #define XENFB_IN_RING_SIZE 1024
76 #define XENFB_IN_RING_LEN (XENFB_IN_RING_SIZE / XENFB_IN_EVENT_SIZE)
77 #define XENFB_IN_RING_OFFS 1024
78 #define XENFB_IN_RING(page) \
79 	((union xenfb_in_event *)((char *)(page) + XENFB_IN_RING_OFFS))
80 #define XENFB_IN_RING_REF(page, idx) \
81 	(XENFB_IN_RING((page))[(idx) % XENFB_IN_RING_LEN])
82 
83 #define XENFB_OUT_RING_SIZE 2048
84 #define XENFB_OUT_RING_LEN (XENFB_OUT_RING_SIZE / XENFB_OUT_EVENT_SIZE)
85 #define XENFB_OUT_RING_OFFS (XENFB_IN_RING_OFFS + XENFB_IN_RING_SIZE)
86 #define XENFB_OUT_RING(page) \
87 	((union xenfb_out_event *)((char *)(page) + XENFB_OUT_RING_OFFS))
88 #define XENFB_OUT_RING_REF(page, idx) \
89 	(XENFB_OUT_RING((page))[(idx) % XENFB_OUT_RING_LEN])
90 
91 struct xenfb_page {
92 	uint32_t in_cons, in_prod;
93 	uint32_t out_cons, out_prod;
94 
95 	int32_t width;          /* width of the framebuffer (in pixels) */
96 	int32_t height;         /* height of the framebuffer (in pixels) */
97 	uint32_t line_length;   /* length of a row of pixels (in bytes) */
98 	uint32_t mem_length;    /* length of the framebuffer (in bytes) */
99 	uint8_t depth;          /* depth of a pixel (in bits) */
100 
101 	/*
102 	 * Framebuffer page directory
103 	 *
104 	 * Each directory page holds PAGE_SIZE / sizeof(*pd)
105 	 * framebuffer pages, and can thus map up to PAGE_SIZE *
106 	 * PAGE_SIZE / sizeof(*pd) bytes.  With PAGE_SIZE == 4096 and
107 	 * sizeof(unsigned long) == 4/8, that's 4 Megs 32 bit and 2
108 	 * Megs 64 bit.  256 directories give enough room for a 512
109 	 * Meg framebuffer with a max resolution of 12,800x10,240.
110 	 * Should be enough for a while with room leftover for
111 	 * expansion.
112 	 */
113 	unsigned long pd[256];
114 };
115 
116 /*
117  * Wart: xenkbd needs to know default resolution.  Put it here until a
118  * better solution is found, but don't leak it to the backend.
119  */
120 #ifdef __KERNEL__
121 #define XENFB_WIDTH 800
122 #define XENFB_HEIGHT 600
123 #define XENFB_DEPTH 32
124 #endif
125 
126 #endif
127