xref: /linux-6.15/include/linux/screen_info.h (revision 7828b7bb)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _SCREEN_INFO_H
3 #define _SCREEN_INFO_H
4 
5 #include <uapi/linux/screen_info.h>
6 
7 #include <linux/bits.h>
8 
9 /**
10  * SCREEN_INFO_MAX_RESOURCES - maximum number of resources per screen_info
11  */
12 #define SCREEN_INFO_MAX_RESOURCES	3
13 
14 struct pci_dev;
15 struct resource;
16 
17 static inline bool __screen_info_has_lfb(unsigned int type)
18 {
19 	return (type == VIDEO_TYPE_VLFB) || (type == VIDEO_TYPE_EFI);
20 }
21 
22 static inline u64 __screen_info_lfb_base(const struct screen_info *si)
23 {
24 	u64 lfb_base = si->lfb_base;
25 
26 	if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE)
27 		lfb_base |= (u64)si->ext_lfb_base << 32;
28 
29 	return lfb_base;
30 }
31 
32 static inline void __screen_info_set_lfb_base(struct screen_info *si, u64 lfb_base)
33 {
34 	si->lfb_base = lfb_base & GENMASK_ULL(31, 0);
35 	si->ext_lfb_base = (lfb_base & GENMASK_ULL(63, 32)) >> 32;
36 
37 	if (si->ext_lfb_base)
38 		si->capabilities |= VIDEO_CAPABILITY_64BIT_BASE;
39 	else
40 		si->capabilities &= ~VIDEO_CAPABILITY_64BIT_BASE;
41 }
42 
43 static inline u64 __screen_info_lfb_size(const struct screen_info *si, unsigned int type)
44 {
45 	u64 lfb_size = si->lfb_size;
46 
47 	if (type == VIDEO_TYPE_VLFB)
48 		lfb_size <<= 16;
49 	return lfb_size;
50 }
51 
52 static inline unsigned int __screen_info_video_type(unsigned int type)
53 {
54 	switch (type) {
55 	case VIDEO_TYPE_MDA:
56 	case VIDEO_TYPE_CGA:
57 	case VIDEO_TYPE_EGAM:
58 	case VIDEO_TYPE_EGAC:
59 	case VIDEO_TYPE_VGAC:
60 	case VIDEO_TYPE_VLFB:
61 	case VIDEO_TYPE_PICA_S3:
62 	case VIDEO_TYPE_MIPS_G364:
63 	case VIDEO_TYPE_SGI:
64 	case VIDEO_TYPE_TGAC:
65 	case VIDEO_TYPE_SUN:
66 	case VIDEO_TYPE_SUNPCI:
67 	case VIDEO_TYPE_PMAC:
68 	case VIDEO_TYPE_EFI:
69 		return type;
70 	default:
71 		return 0;
72 	}
73 }
74 
75 /**
76  * screen_info_video_type() - Decodes the video type from struct screen_info
77  * @si: an instance of struct screen_info
78  *
79  * Returns:
80  * A VIDEO_TYPE_ constant representing si's type of video display, or 0 otherwise.
81  */
82 static inline unsigned int screen_info_video_type(const struct screen_info *si)
83 {
84 	unsigned int type;
85 
86 	// check if display output is on
87 	if (!si->orig_video_isVGA)
88 		return 0;
89 
90 	// check for a known VIDEO_TYPE_ constant
91 	type = __screen_info_video_type(si->orig_video_isVGA);
92 	if (type)
93 		return si->orig_video_isVGA;
94 
95 	// check if text mode has been initialized
96 	if (!si->orig_video_lines || !si->orig_video_cols)
97 		return 0;
98 
99 	// 80x25 text, mono
100 	if (si->orig_video_mode == 0x07) {
101 		if ((si->orig_video_ega_bx & 0xff) != 0x10)
102 			return VIDEO_TYPE_EGAM;
103 		else
104 			return VIDEO_TYPE_MDA;
105 	}
106 
107 	// EGA/VGA, 16 colors
108 	if ((si->orig_video_ega_bx & 0xff) != 0x10) {
109 		if (si->orig_video_isVGA)
110 			return VIDEO_TYPE_VGAC;
111 		else
112 			return VIDEO_TYPE_EGAC;
113 	}
114 
115 	// the rest...
116 	return VIDEO_TYPE_CGA;
117 }
118 
119 ssize_t screen_info_resources(const struct screen_info *si, struct resource *r, size_t num);
120 
121 #if defined(CONFIG_PCI)
122 void screen_info_apply_fixups(void);
123 struct pci_dev *screen_info_pci_dev(const struct screen_info *si);
124 #else
125 static inline void screen_info_apply_fixups(void)
126 { }
127 static inline struct pci_dev *screen_info_pci_dev(const struct screen_info *si)
128 {
129 	return NULL;
130 }
131 #endif
132 
133 extern struct screen_info screen_info;
134 
135 #endif /* _SCREEN_INFO_H */
136