screen_info.h

  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
 14struct pci_dev;
 15struct pixel_format;
 16struct resource;
 17
 18static inline bool __screen_info_has_lfb(unsigned int type)
 19{
 20	return (type == VIDEO_TYPE_VLFB) || (type == VIDEO_TYPE_EFI);
 21}
 22
 23static inline u64 __screen_info_lfb_base(const struct screen_info *si)
 24{
 25	u64 lfb_base = si->lfb_base;
 26
 27	if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE)
 28		lfb_base |= (u64)si->ext_lfb_base << 32;
 29
 30	return lfb_base;
 31}
 32
 33static inline void __screen_info_set_lfb_base(struct screen_info *si, u64 lfb_base)
 34{
 35	si->lfb_base = lfb_base & GENMASK_ULL(31, 0);
 36	si->ext_lfb_base = (lfb_base & GENMASK_ULL(63, 32)) >> 32;
 37
 38	if (si->ext_lfb_base)
 39		si->capabilities |= VIDEO_CAPABILITY_64BIT_BASE;
 40	else
 41		si->capabilities &= ~VIDEO_CAPABILITY_64BIT_BASE;
 42}
 43
 44static inline u64 __screen_info_lfb_size(const struct screen_info *si, unsigned int type)
 45{
 46	u64 lfb_size = si->lfb_size;
 47
 48	if (type == VIDEO_TYPE_VLFB)
 49		lfb_size <<= 16;
 50	return lfb_size;
 51}
 52
 53static inline bool __screen_info_vbe_mode_nonvga(const struct screen_info *si)
 54{
 55	/*
 56	 * VESA modes typically run on VGA hardware. Set bit 5 signals that this
 57	 * is not the case. Drivers can then not make use of VGA resources. See
 58	 * Sec 4.4 of the VBE 2.0 spec.
 59	 */
 60	return si->vesa_attributes & BIT(5);
 61}
 62
 63static inline unsigned int __screen_info_video_type(unsigned int type)
 64{
 65	switch (type) {
 66	case VIDEO_TYPE_MDA:
 67	case VIDEO_TYPE_CGA:
 68	case VIDEO_TYPE_EGAM:
 69	case VIDEO_TYPE_EGAC:
 70	case VIDEO_TYPE_VGAC:
 71	case VIDEO_TYPE_VLFB:
 72	case VIDEO_TYPE_PICA_S3:
 73	case VIDEO_TYPE_MIPS_G364:
 74	case VIDEO_TYPE_SGI:
 75	case VIDEO_TYPE_TGAC:
 76	case VIDEO_TYPE_SUN:
 77	case VIDEO_TYPE_SUNPCI:
 78	case VIDEO_TYPE_PMAC:
 79	case VIDEO_TYPE_EFI:
 80		return type;
 81	default:
 82		return 0;
 83	}
 84}
 85
 86/**
 87 * screen_info_video_type() - Decodes the video type from struct screen_info
 88 * @si: an instance of struct screen_info
 89 *
 90 * Returns:
 91 * A VIDEO_TYPE_ constant representing si's type of video display, or 0 otherwise.
 92 */
 93static inline unsigned int screen_info_video_type(const struct screen_info *si)
 94{
 95	unsigned int type;
 96
 97	// check if display output is on
 98	if (!si->orig_video_isVGA)
 99		return 0;
100
101	// check for a known VIDEO_TYPE_ constant
102	type = __screen_info_video_type(si->orig_video_isVGA);
103	if (type)
104		return si->orig_video_isVGA;
105
106	// check if text mode has been initialized
107	if (!si->orig_video_lines || !si->orig_video_cols)
108		return 0;
109
110	// 80x25 text, mono
111	if (si->orig_video_mode == 0x07) {
112		if ((si->orig_video_ega_bx & 0xff) != 0x10)
113			return VIDEO_TYPE_EGAM;
114		else
115			return VIDEO_TYPE_MDA;
116	}
117
118	// EGA/VGA, 16 colors
119	if ((si->orig_video_ega_bx & 0xff) != 0x10) {
120		if (si->orig_video_isVGA)
121			return VIDEO_TYPE_VGAC;
122		else
123			return VIDEO_TYPE_EGAC;
124	}
125
126	// the rest...
127	return VIDEO_TYPE_CGA;
128}
129
130static inline u32 __screen_info_vesapm_info_base(const struct screen_info *si)
131{
132	if (si->vesapm_seg < 0xc000)
133		return 0;
134	return (si->vesapm_seg << 4) + si->vesapm_off;
135}
136
137ssize_t screen_info_resources(const struct screen_info *si, struct resource *r, size_t num);
138
139u32 __screen_info_lfb_bits_per_pixel(const struct screen_info *si);
140int screen_info_pixel_format(const struct screen_info *si, struct pixel_format *f);
141
142#if defined(CONFIG_PCI)
143void screen_info_apply_fixups(void);
144struct pci_dev *screen_info_pci_dev(const struct screen_info *si);
145#else
146static inline void screen_info_apply_fixups(void)
147{ }
148static inline struct pci_dev *screen_info_pci_dev(const struct screen_info *si)
149{
150	return NULL;
151}
152#endif
153
154extern struct screen_info screen_info;
155
156#endif /* _SCREEN_INFO_H */