1// SPDX-License-Identifier: GPL-2.0
2
3#include <linux/export.h>
4#include <linux/ioport.h>
5#include <linux/screen_info.h>
6#include <linux/string.h>
7
8static void resource_init_named(struct resource *r,
9 resource_size_t start, resource_size_t size,
10 const char *name, unsigned int flags)
11{
12 memset(r, 0, sizeof(*r));
13
14 r->start = start;
15 r->end = start + size - 1;
16 r->name = name;
17 r->flags = flags;
18}
19
20static void resource_init_io_named(struct resource *r,
21 resource_size_t start, resource_size_t size,
22 const char *name)
23{
24 resource_init_named(r, start, size, name, IORESOURCE_IO);
25}
26
27static void resource_init_mem_named(struct resource *r,
28 resource_size_t start, resource_size_t size,
29 const char *name)
30{
31 resource_init_named(r, start, size, name, IORESOURCE_MEM);
32}
33
34static inline bool __screen_info_has_ega_gfx(unsigned int mode)
35{
36 switch (mode) {
37 case 0x0d: /* 320x200-4 */
38 case 0x0e: /* 640x200-4 */
39 case 0x0f: /* 640x350-1 */
40 case 0x10: /* 640x350-4 */
41 return true;
42 default:
43 return false;
44 }
45}
46
47static inline bool __screen_info_has_vga_gfx(unsigned int mode)
48{
49 switch (mode) {
50 case 0x10: /* 640x480-1 */
51 case 0x12: /* 640x480-4 */
52 case 0x13: /* 320-200-8 */
53 case 0x6a: /* 800x600-4 (VESA) */
54 return true;
55 default:
56 return __screen_info_has_ega_gfx(mode);
57 }
58}
59
60/**
61 * screen_info_resources() - Get resources from screen_info structure
62 * @si: the screen_info
63 * @r: pointer to an array of resource structures
64 * @num: number of elements in @r:
65 *
66 * Returns:
67 * The number of resources stored in @r on success, or a negative errno code otherwise.
68 *
69 * A call to screen_info_resources() returns the resources consumed by the
70 * screen_info's device or framebuffer. The result is stored in the caller-supplied
71 * array @r with up to @num elements. The function returns the number of
72 * initialized elements.
73 */
74ssize_t screen_info_resources(const struct screen_info *si, struct resource *r, size_t num)
75{
76 struct resource *pos = r;
77 unsigned int type = screen_info_video_type(si);
78 u64 base, size;
79
80 switch (type) {
81 case VIDEO_TYPE_MDA:
82 if (num > 0)
83 resource_init_io_named(r: pos++, start: 0x3b0, size: 12, name: "mda");
84 if (num > 1)
85 resource_init_io_named(r: pos++, start: 0x3bf, size: 0x01, name: "mda");
86 if (num > 2)
87 resource_init_mem_named(r: pos++, start: 0xb0000, size: 0x2000, name: "mda");
88 break;
89 case VIDEO_TYPE_CGA:
90 if (num > 0)
91 resource_init_io_named(r: pos++, start: 0x3d4, size: 0x02, name: "cga");
92 if (num > 1)
93 resource_init_mem_named(r: pos++, start: 0xb8000, size: 0x2000, name: "cga");
94 break;
95 case VIDEO_TYPE_EGAM:
96 if (num > 0)
97 resource_init_io_named(r: pos++, start: 0x3bf, size: 0x10, name: "ega");
98 if (num > 1)
99 resource_init_mem_named(r: pos++, start: 0xb0000, size: 0x8000, name: "ega");
100 break;
101 case VIDEO_TYPE_EGAC:
102 if (num > 0)
103 resource_init_io_named(r: pos++, start: 0x3c0, size: 0x20, name: "ega");
104 if (num > 1) {
105 if (__screen_info_has_ega_gfx(mode: si->orig_video_mode))
106 resource_init_mem_named(r: pos++, start: 0xa0000, size: 0x10000, name: "ega");
107 else
108 resource_init_mem_named(r: pos++, start: 0xb8000, size: 0x8000, name: "ega");
109 }
110 break;
111 case VIDEO_TYPE_VGAC:
112 if (num > 0)
113 resource_init_io_named(r: pos++, start: 0x3c0, size: 0x20, name: "vga+");
114 if (num > 1) {
115 if (__screen_info_has_vga_gfx(mode: si->orig_video_mode))
116 resource_init_mem_named(r: pos++, start: 0xa0000, size: 0x10000, name: "vga+");
117 else
118 resource_init_mem_named(r: pos++, start: 0xb8000, size: 0x8000, name: "vga+");
119 }
120 break;
121 case VIDEO_TYPE_VLFB:
122 case VIDEO_TYPE_EFI:
123 base = __screen_info_lfb_base(si);
124 if (!base)
125 break;
126 size = __screen_info_lfb_size(si, type);
127 if (!size)
128 break;
129 if (num > 0)
130 resource_init_mem_named(r: pos++, start: base, size, name: "lfb");
131 break;
132 case VIDEO_TYPE_PICA_S3:
133 case VIDEO_TYPE_MIPS_G364:
134 case VIDEO_TYPE_SGI:
135 case VIDEO_TYPE_TGAC:
136 case VIDEO_TYPE_SUN:
137 case VIDEO_TYPE_SUNPCI:
138 case VIDEO_TYPE_PMAC:
139 default:
140 /* not supported */
141 return -EINVAL;
142 }
143
144 return pos - r;
145}
146EXPORT_SYMBOL(screen_info_resources);
147

source code of linux/drivers/video/screen_info_generic.c