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237 lines · 6.2 KiB

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
8#include <video/pixel_format.h>
9
10static void resource_init_named(struct resource *r,
11 resource_size_t start, resource_size_t size,
12 const char *name, unsigned int flags)
13{
14 memset(r, 0, sizeof(*r));
15
16 r->start = start;
17 r->end = start + size - 1;
18 r->name = name;
19 r->flags = flags;
20}
21
22static void resource_init_io_named(struct resource *r,
23 resource_size_t start, resource_size_t size,
24 const char *name)
25{
26 resource_init_named(r, start, size, name, IORESOURCE_IO);
27}
28
29static void resource_init_mem_named(struct resource *r,
30 resource_size_t start, resource_size_t size,
31 const char *name)
32{
33 resource_init_named(r, start, size, name, IORESOURCE_MEM);
34}
35
36static inline bool __screen_info_has_ega_gfx(unsigned int mode)
37{
38 switch (mode) {
39 case 0x0d: /* 320x200-4 */
40 case 0x0e: /* 640x200-4 */
41 case 0x0f: /* 640x350-1 */
42 case 0x10: /* 640x350-4 */
43 return true;
44 default:
45 return false;
46 }
47}
48
49static inline bool __screen_info_has_vga_gfx(unsigned int mode)
50{
51 switch (mode) {
52 case 0x10: /* 640x480-1 */
53 case 0x12: /* 640x480-4 */
54 case 0x13: /* 320-200-8 */
55 case 0x6a: /* 800x600-4 (VESA) */
56 return true;
57 default:
58 return __screen_info_has_ega_gfx(mode);
59 }
60}
61
62/**
63 * screen_info_resources() - Get resources from screen_info structure
64 * @si: the screen_info
65 * @r: pointer to an array of resource structures
66 * @num: number of elements in @r:
67 *
68 * Returns:
69 * The number of resources stored in @r on success, or a negative errno code otherwise.
70 *
71 * A call to screen_info_resources() returns the resources consumed by the
72 * screen_info's device or framebuffer. The result is stored in the caller-supplied
73 * array @r with up to @num elements. The function returns the number of
74 * initialized elements.
75 */
76ssize_t screen_info_resources(const struct screen_info *si, struct resource *r, size_t num)
77{
78 struct resource *pos = r;
79 unsigned int type = screen_info_video_type(si);
80 u64 base, size;
81
82 switch (type) {
83 case VIDEO_TYPE_MDA:
84 if (num > 0)
85 resource_init_io_named(pos++, 0x3b0, 12, "mda");
86 if (num > 1)
87 resource_init_io_named(pos++, 0x3bf, 0x01, "mda");
88 if (num > 2)
89 resource_init_mem_named(pos++, 0xb0000, 0x2000, "mda");
90 break;
91 case VIDEO_TYPE_CGA:
92 if (num > 0)
93 resource_init_io_named(pos++, 0x3d4, 0x02, "cga");
94 if (num > 1)
95 resource_init_mem_named(pos++, 0xb8000, 0x2000, "cga");
96 break;
97 case VIDEO_TYPE_EGAM:
98 if (num > 0)
99 resource_init_io_named(pos++, 0x3bf, 0x10, "ega");
100 if (num > 1)
101 resource_init_mem_named(pos++, 0xb0000, 0x8000, "ega");
102 break;
103 case VIDEO_TYPE_EGAC:
104 if (num > 0)
105 resource_init_io_named(pos++, 0x3c0, 0x20, "ega");
106 if (num > 1) {
107 if (__screen_info_has_ega_gfx(si->orig_video_mode))
108 resource_init_mem_named(pos++, 0xa0000, 0x10000, "ega");
109 else
110 resource_init_mem_named(pos++, 0xb8000, 0x8000, "ega");
111 }
112 break;
113 case VIDEO_TYPE_VGAC:
114 if (num > 0)
115 resource_init_io_named(pos++, 0x3c0, 0x20, "vga+");
116 if (num > 1) {
117 if (__screen_info_has_vga_gfx(si->orig_video_mode))
118 resource_init_mem_named(pos++, 0xa0000, 0x10000, "vga+");
119 else
120 resource_init_mem_named(pos++, 0xb8000, 0x8000, "vga+");
121 }
122 break;
123 case VIDEO_TYPE_VLFB:
124 case VIDEO_TYPE_EFI:
125 base = __screen_info_lfb_base(si);
126 if (!base)
127 break;
128 size = __screen_info_lfb_size(si, type);
129 if (!size)
130 break;
131 if (num > 0)
132 resource_init_mem_named(pos++, base, size, "lfb");
133 break;
134 case VIDEO_TYPE_PICA_S3:
135 case VIDEO_TYPE_MIPS_G364:
136 case VIDEO_TYPE_SGI:
137 case VIDEO_TYPE_TGAC:
138 case VIDEO_TYPE_SUN:
139 case VIDEO_TYPE_SUNPCI:
140 case VIDEO_TYPE_PMAC:
141 default:
142 /* not supported */
143 return -EINVAL;
144 }
145
146 return pos - r;
147}
148EXPORT_SYMBOL(screen_info_resources);
149
150/*
151 * The meaning of depth and bpp for direct-color formats is
152 * inconsistent:
153 *
154 * - DRM format info specifies depth as the number of color
155 * bits; including alpha, but not including filler bits.
156 * - Linux' EFI platform code computes lfb_depth from the
157 * individual color channels, including the reserved bits.
158 * - VBE 1.1 defines lfb_depth for XRGB1555 as 16, but later
159 * versions use 15.
160 * - On the kernel command line, 'bpp' of 32 is usually
161 * XRGB8888 including the filler bits, but 15 is XRGB1555
162 * not including the filler bit.
163 *
164 * It is not easily possible to fix this in struct screen_info,
165 * as this could break UAPI. The best solution is to compute
166 * bits_per_pixel from the color bits, reserved bits and
167 * reported lfb_depth, whichever is highest.
168 */
169
170u32 __screen_info_lfb_bits_per_pixel(const struct screen_info *si)
171{
172 u32 bits_per_pixel = si->lfb_depth;
173
174 if (bits_per_pixel > 8) {
175 bits_per_pixel = max(max3(si->red_size + si->red_pos,
176 si->green_size + si->green_pos,
177 si->blue_size + si->blue_pos),
178 si->rsvd_size + si->rsvd_pos);
179 bits_per_pixel = max_t(u32, bits_per_pixel, si->lfb_depth);
180 }
181
182 return bits_per_pixel;
183}
184EXPORT_SYMBOL(__screen_info_lfb_bits_per_pixel);
185
186static int __screen_info_lfb_pixel_format(const struct screen_info *si, struct pixel_format *f)
187{
188 u32 bits_per_pixel = __screen_info_lfb_bits_per_pixel(si);
189
190 if (bits_per_pixel > U8_MAX)
191 return -EINVAL;
192
193 f->bits_per_pixel = bits_per_pixel;
194
195 if (si->lfb_depth > 8) {
196 f->indexed = false;
197 f->alpha.offset = 0;
198 f->alpha.length = 0;
199 f->red.offset = si->red_pos;
200 f->red.length = si->red_size;
201 f->green.offset = si->green_pos;
202 f->green.length = si->green_size;
203 f->blue.offset = si->blue_pos;
204 f->blue.length = si->blue_size;
205 } else {
206 f->indexed = true;
207 f->index.offset = 0;
208 f->index.length = si->lfb_depth;
209 }
210
211 return 0;
212}
213
214/**
215 * screen_info_pixel_format - Returns the screen-info format as pixel-format description
216 *
217 * @si: the screen_info
218 * @f: pointer to return pixel-format description
219 *
220 * Returns:
221 * 0 on success, or a negative errno code otherwise.
222 */
223int screen_info_pixel_format(const struct screen_info *si, struct pixel_format *f)
224{
225 unsigned int type = screen_info_video_type(si);
226
227 /* TODO: Add support for additional types as needed. */
228 switch (type) {
229 case VIDEO_TYPE_VLFB:
230 case VIDEO_TYPE_EFI:
231 return __screen_info_lfb_pixel_format(si, f);
232 }
233
234 /* not supported */
235 return -EINVAL;
236}
237EXPORT_SYMBOL(screen_info_pixel_format);