xref: /openbmc/linux/arch/x86/boot/video-vesa.c (revision 545e4006)
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 __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
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 			   We don't require CONFIG_FB_VESA, however, since
97 			   some of the other framebuffer drivers can use
98 			   this mode-setting, too. */
99 			mi = GET_HEAP(struct mode_info, 1);
100 			mi->mode = mode + VIDEO_FIRST_VESA;
101 			mi->depth = vminfo.bpp;
102 			mi->x = vminfo.h_res;
103 			mi->y = vminfo.v_res;
104 			nmodes++;
105 #endif
106 		}
107 	}
108 
109 	return nmodes;
110 #else
111 	return 0;
112 #endif /* CONFIG_VIDEO_VESA */
113 }
114 
115 static int vesa_set_mode(struct mode_info *mode)
116 {
117 	u16 ax, bx, cx, di;
118 	int is_graphic;
119 	u16 vesa_mode = mode->mode - VIDEO_FIRST_VESA;
120 
121 	memset(&vminfo, 0, sizeof vminfo); /* Just in case... */
122 
123 	ax = 0x4f01;
124 	cx = vesa_mode;
125 	di = (size_t)&vminfo;
126 	asm(INT10
127 	    : "+a" (ax), "+c" (cx), "+D" (di), "=m" (vminfo)
128 	    : : "ebx", "edx", "esi");
129 
130 	if (ax != 0x004f)
131 		return -1;
132 
133 	if ((vminfo.mode_attr & 0x15) == 0x05) {
134 		/* It's a supported text mode */
135 		is_graphic = 0;
136 	} else if ((vminfo.mode_attr & 0x99) == 0x99) {
137 		/* It's a graphics mode with linear frame buffer */
138 		is_graphic = 1;
139 		vesa_mode |= 0x4000; /* Request linear frame buffer */
140 	} else {
141 		return -1;	/* Invalid mode */
142 	}
143 
144 
145 	ax = 0x4f02;
146 	bx = vesa_mode;
147 	di = 0;
148 	asm volatile(INT10
149 		     : "+a" (ax), "+b" (bx), "+D" (di)
150 		     : : "ecx", "edx", "esi");
151 
152 	if (ax != 0x004f)
153 		return -1;
154 
155 	graphic_mode = is_graphic;
156 	if (!is_graphic) {
157 		/* Text mode */
158 		force_x = mode->x;
159 		force_y = mode->y;
160 		do_restore = 1;
161 	} else {
162 		/* Graphics mode */
163 		vesa_store_mode_params_graphics();
164 	}
165 
166 	return 0;
167 }
168 
169 
170 #ifndef _WAKEUP
171 
172 /* Switch DAC to 8-bit mode */
173 static void vesa_dac_set_8bits(void)
174 {
175 	u8 dac_size = 6;
176 
177 	/* If possible, switch the DAC to 8-bit mode */
178 	if (vginfo.capabilities & 1) {
179 		u16 ax, bx;
180 
181 		ax = 0x4f08;
182 		bx = 0x0800;
183 		asm volatile(INT10
184 			     : "+a" (ax), "+b" (bx)
185 			     : : "ecx", "edx", "esi", "edi");
186 
187 		if (ax == 0x004f)
188 			dac_size = bx >> 8;
189 	}
190 
191 	/* Set the color sizes to the DAC size, and offsets to 0 */
192 	boot_params.screen_info.red_size = dac_size;
193 	boot_params.screen_info.green_size = dac_size;
194 	boot_params.screen_info.blue_size = dac_size;
195 	boot_params.screen_info.rsvd_size = dac_size;
196 
197 	boot_params.screen_info.red_pos = 0;
198 	boot_params.screen_info.green_pos = 0;
199 	boot_params.screen_info.blue_pos = 0;
200 	boot_params.screen_info.rsvd_pos = 0;
201 }
202 
203 /* Save the VESA protected mode info */
204 static void vesa_store_pm_info(void)
205 {
206 	u16 ax, bx, di, es;
207 
208 	ax = 0x4f0a;
209 	bx = di = 0;
210 	asm("pushw %%es; "INT10"; movw %%es,%0; popw %%es"
211 	    : "=d" (es), "+a" (ax), "+b" (bx), "+D" (di)
212 	    : : "ecx", "esi");
213 
214 	if (ax != 0x004f)
215 		return;
216 
217 	boot_params.screen_info.vesapm_seg = es;
218 	boot_params.screen_info.vesapm_off = di;
219 }
220 
221 /*
222  * Save video mode parameters for graphics mode
223  */
224 static void vesa_store_mode_params_graphics(void)
225 {
226 	/* Tell the kernel we're in VESA graphics mode */
227 	boot_params.screen_info.orig_video_isVGA = 0x23;
228 
229 	/* Mode parameters */
230 	boot_params.screen_info.vesa_attributes = vminfo.mode_attr;
231 	boot_params.screen_info.lfb_linelength = vminfo.logical_scan;
232 	boot_params.screen_info.lfb_width = vminfo.h_res;
233 	boot_params.screen_info.lfb_height = vminfo.v_res;
234 	boot_params.screen_info.lfb_depth = vminfo.bpp;
235 	boot_params.screen_info.pages = vminfo.image_planes;
236 	boot_params.screen_info.lfb_base = vminfo.lfb_ptr;
237 	memcpy(&boot_params.screen_info.red_size,
238 	       &vminfo.rmask, 8);
239 
240 	/* General parameters */
241 	boot_params.screen_info.lfb_size = vginfo.total_memory;
242 
243 	if (vminfo.bpp <= 8)
244 		vesa_dac_set_8bits();
245 
246 	vesa_store_pm_info();
247 }
248 
249 /*
250  * Save EDID information for the kernel; this is invoked, separately,
251  * after mode-setting.
252  */
253 void vesa_store_edid(void)
254 {
255 #ifdef CONFIG_FIRMWARE_EDID
256 	u16 ax, bx, cx, dx, di;
257 
258 	/* Apparently used as a nonsense token... */
259 	memset(&boot_params.edid_info, 0x13, sizeof boot_params.edid_info);
260 
261 	if (vginfo.version < 0x0200)
262 		return;		/* EDID requires VBE 2.0+ */
263 
264 	ax = 0x4f15;		/* VBE DDC */
265 	bx = 0x0000;		/* Report DDC capabilities */
266 	cx = 0;			/* Controller 0 */
267 	di = 0;			/* ES:DI must be 0 by spec */
268 
269 	/* Note: The VBE DDC spec is different from the main VESA spec;
270 	   we genuinely have to assume all registers are destroyed here. */
271 
272 	asm("pushw %%es; movw %2,%%es; "INT10"; popw %%es"
273 	    : "+a" (ax), "+b" (bx)
274 	    :  "c" (cx), "D" (di)
275 	    : "esi");
276 
277 	if (ax != 0x004f)
278 		return;		/* No EDID */
279 
280 	/* BH = time in seconds to transfer EDD information */
281 	/* BL = DDC level supported */
282 
283 	ax = 0x4f15;		/* VBE DDC */
284 	bx = 0x0001;		/* Read EDID */
285 	cx = 0;			/* Controller 0 */
286 	dx = 0;			/* EDID block number */
287 	di =(size_t) &boot_params.edid_info; /* (ES:)Pointer to block */
288 	asm(INT10
289 	    : "+a" (ax), "+b" (bx), "+d" (dx), "=m" (boot_params.edid_info)
290 	    : "c" (cx), "D" (di)
291 	    : "esi");
292 #endif /* CONFIG_FIRMWARE_EDID */
293 }
294 
295 #endif /* not _WAKEUP */
296 
297 __videocard video_vesa =
298 {
299 	.card_name	= "VESA",
300 	.probe		= vesa_probe,
301 	.set_mode	= vesa_set_mode,
302 	.xmode_first	= VIDEO_FIRST_VESA,
303 	.xmode_n	= 0x200,
304 };
305