xref: /openbmc/linux/arch/x86/boot/video-vesa.c (revision b04b4f78)
1 /* -*- linux-c -*- ------------------------------------------------------- *
2  *
3  *   Copyright (C) 1991, 1992 Linus Torvalds
4  *   Copyright 2007 rPath, Inc. - All Rights Reserved
5  *
6  *   This file is part of the Linux kernel, and is made available under
7  *   the terms of the GNU General Public License version 2.
8  *
9  * ----------------------------------------------------------------------- */
10 
11 /*
12  * VESA text modes
13  */
14 
15 #include "boot.h"
16 #include "video.h"
17 #include "vesa.h"
18 
19 /* VESA information */
20 static struct vesa_general_info vginfo;
21 static struct vesa_mode_info vminfo;
22 
23 static __videocard video_vesa;
24 
25 #ifndef _WAKEUP
26 static void vesa_store_mode_params_graphics(void);
27 #else /* _WAKEUP */
28 static inline void vesa_store_mode_params_graphics(void) {}
29 #endif /* _WAKEUP */
30 
31 static int vesa_probe(void)
32 {
33 #if defined(CONFIG_VIDEO_VESA) || defined(CONFIG_FIRMWARE_EDID)
34 	u16 ax, cx, di;
35 	u16 mode;
36 	addr_t mode_ptr;
37 	struct mode_info *mi;
38 	int nmodes = 0;
39 
40 	video_vesa.modes = GET_HEAP(struct mode_info, 0);
41 
42 	ax = 0x4f00;
43 	di = (size_t)&vginfo;
44 	asm(INT10
45 	    : "+a" (ax), "+D" (di), "=m" (vginfo)
46 	    : : "ebx", "ecx", "edx", "esi");
47 
48 	if (ax != 0x004f ||
49 	    vginfo.signature != VESA_MAGIC ||
50 	    vginfo.version < 0x0102)
51 		return 0;	/* Not present */
52 #endif /* CONFIG_VIDEO_VESA || CONFIG_FIRMWARE_EDID */
53 #ifdef CONFIG_VIDEO_VESA
54 	set_fs(vginfo.video_mode_ptr.seg);
55 	mode_ptr = vginfo.video_mode_ptr.off;
56 
57 	while ((mode = rdfs16(mode_ptr)) != 0xffff) {
58 		mode_ptr += 2;
59 
60 		if (!heap_free(sizeof(struct mode_info)))
61 			break;	/* Heap full, can't save mode info */
62 
63 		if (mode & ~0x1ff)
64 			continue;
65 
66 		memset(&vminfo, 0, sizeof vminfo); /* Just in case... */
67 
68 		ax = 0x4f01;
69 		cx = mode;
70 		di = (size_t)&vminfo;
71 		asm(INT10
72 		    : "+a" (ax), "+c" (cx), "+D" (di), "=m" (vminfo)
73 		    : : "ebx", "edx", "esi");
74 
75 		if (ax != 0x004f)
76 			continue;
77 
78 		if ((vminfo.mode_attr & 0x15) == 0x05) {
79 			/* Text Mode, TTY BIOS supported,
80 			   supported by hardware */
81 			mi = GET_HEAP(struct mode_info, 1);
82 			mi->mode  = mode + VIDEO_FIRST_VESA;
83 			mi->depth = 0; /* text */
84 			mi->x     = vminfo.h_res;
85 			mi->y     = vminfo.v_res;
86 			nmodes++;
87 		} else if ((vminfo.mode_attr & 0x99) == 0x99 &&
88 			   (vminfo.memory_layout == 4 ||
89 			    vminfo.memory_layout == 6) &&
90 			   vminfo.memory_planes == 1) {
91 #ifdef CONFIG_FB_BOOT_VESA_SUPPORT
92 			/* Graphics mode, color, linear frame buffer
93 			   supported.  Only register the mode if
94 			   if framebuffer is configured, however,
95 			   otherwise the user will be left without a screen. */
96 			mi = GET_HEAP(struct mode_info, 1);
97 			mi->mode = mode + VIDEO_FIRST_VESA;
98 			mi->depth = vminfo.bpp;
99 			mi->x = vminfo.h_res;
100 			mi->y = vminfo.v_res;
101 			nmodes++;
102 #endif
103 		}
104 	}
105 
106 	return nmodes;
107 #else
108 	return 0;
109 #endif /* CONFIG_VIDEO_VESA */
110 }
111 
112 static int vesa_set_mode(struct mode_info *mode)
113 {
114 	u16 ax, bx, cx, di;
115 	int is_graphic;
116 	u16 vesa_mode = mode->mode - VIDEO_FIRST_VESA;
117 
118 	memset(&vminfo, 0, sizeof vminfo); /* Just in case... */
119 
120 	ax = 0x4f01;
121 	cx = vesa_mode;
122 	di = (size_t)&vminfo;
123 	asm(INT10
124 	    : "+a" (ax), "+c" (cx), "+D" (di), "=m" (vminfo)
125 	    : : "ebx", "edx", "esi");
126 
127 	if (ax != 0x004f)
128 		return -1;
129 
130 	if ((vminfo.mode_attr & 0x15) == 0x05) {
131 		/* It's a supported text mode */
132 		is_graphic = 0;
133 #ifdef CONFIG_FB_BOOT_VESA_SUPPORT
134 	} else if ((vminfo.mode_attr & 0x99) == 0x99) {
135 		/* It's a graphics mode with linear frame buffer */
136 		is_graphic = 1;
137 		vesa_mode |= 0x4000; /* Request linear frame buffer */
138 #endif
139 	} else {
140 		return -1;	/* Invalid mode */
141 	}
142 
143 
144 	ax = 0x4f02;
145 	bx = vesa_mode;
146 	di = 0;
147 	asm volatile(INT10
148 		     : "+a" (ax), "+b" (bx), "+D" (di)
149 		     : : "ecx", "edx", "esi");
150 
151 	if (ax != 0x004f)
152 		return -1;
153 
154 	graphic_mode = is_graphic;
155 	if (!is_graphic) {
156 		/* Text mode */
157 		force_x = mode->x;
158 		force_y = mode->y;
159 		do_restore = 1;
160 	} else {
161 		/* Graphics mode */
162 		vesa_store_mode_params_graphics();
163 	}
164 
165 	return 0;
166 }
167 
168 
169 #ifndef _WAKEUP
170 
171 /* Switch DAC to 8-bit mode */
172 static void vesa_dac_set_8bits(void)
173 {
174 	u8 dac_size = 6;
175 
176 	/* If possible, switch the DAC to 8-bit mode */
177 	if (vginfo.capabilities & 1) {
178 		u16 ax, bx;
179 
180 		ax = 0x4f08;
181 		bx = 0x0800;
182 		asm volatile(INT10
183 			     : "+a" (ax), "+b" (bx)
184 			     : : "ecx", "edx", "esi", "edi");
185 
186 		if (ax == 0x004f)
187 			dac_size = bx >> 8;
188 	}
189 
190 	/* Set the color sizes to the DAC size, and offsets to 0 */
191 	boot_params.screen_info.red_size = dac_size;
192 	boot_params.screen_info.green_size = dac_size;
193 	boot_params.screen_info.blue_size = dac_size;
194 	boot_params.screen_info.rsvd_size = dac_size;
195 
196 	boot_params.screen_info.red_pos = 0;
197 	boot_params.screen_info.green_pos = 0;
198 	boot_params.screen_info.blue_pos = 0;
199 	boot_params.screen_info.rsvd_pos = 0;
200 }
201 
202 /* Save the VESA protected mode info */
203 static void vesa_store_pm_info(void)
204 {
205 	u16 ax, bx, di, es;
206 
207 	ax = 0x4f0a;
208 	bx = di = 0;
209 	asm("pushw %%es; "INT10"; movw %%es,%0; popw %%es"
210 	    : "=d" (es), "+a" (ax), "+b" (bx), "+D" (di)
211 	    : : "ecx", "esi");
212 
213 	if (ax != 0x004f)
214 		return;
215 
216 	boot_params.screen_info.vesapm_seg = es;
217 	boot_params.screen_info.vesapm_off = di;
218 }
219 
220 /*
221  * Save video mode parameters for graphics mode
222  */
223 static void vesa_store_mode_params_graphics(void)
224 {
225 	/* Tell the kernel we're in VESA graphics mode */
226 	boot_params.screen_info.orig_video_isVGA = VIDEO_TYPE_VLFB;
227 
228 	/* Mode parameters */
229 	boot_params.screen_info.vesa_attributes = vminfo.mode_attr;
230 	boot_params.screen_info.lfb_linelength = vminfo.logical_scan;
231 	boot_params.screen_info.lfb_width = vminfo.h_res;
232 	boot_params.screen_info.lfb_height = vminfo.v_res;
233 	boot_params.screen_info.lfb_depth = vminfo.bpp;
234 	boot_params.screen_info.pages = vminfo.image_planes;
235 	boot_params.screen_info.lfb_base = vminfo.lfb_ptr;
236 	memcpy(&boot_params.screen_info.red_size,
237 	       &vminfo.rmask, 8);
238 
239 	/* General parameters */
240 	boot_params.screen_info.lfb_size = vginfo.total_memory;
241 
242 	if (vminfo.bpp <= 8)
243 		vesa_dac_set_8bits();
244 
245 	vesa_store_pm_info();
246 }
247 
248 /*
249  * Save EDID information for the kernel; this is invoked, separately,
250  * after mode-setting.
251  */
252 void vesa_store_edid(void)
253 {
254 #ifdef CONFIG_FIRMWARE_EDID
255 	u16 ax, bx, cx, dx, di;
256 
257 	/* Apparently used as a nonsense token... */
258 	memset(&boot_params.edid_info, 0x13, sizeof boot_params.edid_info);
259 
260 	if (vginfo.version < 0x0200)
261 		return;		/* EDID requires VBE 2.0+ */
262 
263 	ax = 0x4f15;		/* VBE DDC */
264 	bx = 0x0000;		/* Report DDC capabilities */
265 	cx = 0;			/* Controller 0 */
266 	di = 0;			/* ES:DI must be 0 by spec */
267 
268 	/* Note: The VBE DDC spec is different from the main VESA spec;
269 	   we genuinely have to assume all registers are destroyed here. */
270 
271 	asm("pushw %%es; movw %2,%%es; "INT10"; popw %%es"
272 	    : "+a" (ax), "+b" (bx), "+c" (cx), "+D" (di)
273 	    : : "esi", "edx");
274 
275 	if (ax != 0x004f)
276 		return;		/* No EDID */
277 
278 	/* BH = time in seconds to transfer EDD information */
279 	/* BL = DDC level supported */
280 
281 	ax = 0x4f15;		/* VBE DDC */
282 	bx = 0x0001;		/* Read EDID */
283 	cx = 0;			/* Controller 0 */
284 	dx = 0;			/* EDID block number */
285 	di =(size_t) &boot_params.edid_info; /* (ES:)Pointer to block */
286 	asm(INT10
287 	    : "+a" (ax), "+b" (bx), "+d" (dx), "=m" (boot_params.edid_info),
288 	      "+c" (cx), "+D" (di)
289 	    : : "esi");
290 #endif /* CONFIG_FIRMWARE_EDID */
291 }
292 
293 #endif /* not _WAKEUP */
294 
295 static __videocard video_vesa =
296 {
297 	.card_name	= "VESA",
298 	.probe		= vesa_probe,
299 	.set_mode	= vesa_set_mode,
300 	.xmode_first	= VIDEO_FIRST_VESA,
301 	.xmode_n	= 0x200,
302 };
303