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1 /* ----------------------------------------------------------------------- *
2  *
3  *   Copyright 1999-2008 H. Peter Anvin - All Rights Reserved
4  *   Copyright 2009 Intel Corporation; author: H. Peter Anvin
5  *
6  *   Permission is hereby granted, free of charge, to any person
7  *   obtaining a copy of this software and associated documentation
8  *   files (the "Software"), to deal in the Software without
9  *   restriction, including without limitation the rights to use,
10  *   copy, modify, merge, publish, distribute, sublicense, and/or
11  *   sell copies of the Software, and to permit persons to whom
12  *   the Software is furnished to do so, subject to the following
13  *   conditions:
14  *
15  *   The above copyright notice and this permission notice shall
16  *   be included in all copies or substantial portions of the Software.
17  *
18  *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
19  *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
20  *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
21  *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
22  *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
23  *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
24  *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
25  *   OTHER DEALINGS IN THE SOFTWARE.
26  *
27  * ----------------------------------------------------------------------- */
28 
29 /*
30  * initvesa.c
31  *
32  * Query the VESA BIOS and select a 640x480x32 mode with local mapping
33  * support, if one exists.
34  */
35 
36 #include <inttypes.h>
37 #include <com32.h>
38 #include <stdlib.h>
39 #include <string.h>
40 #include <limits.h>
41 #include <graphics.h>
42 
43 #include "vesa.h"
44 #include "mboot.h"
45 
46 struct vesa_info vesa_info;
47 
set_graphics_mode(const struct multiboot_header * mbh,struct multiboot_info * mbi)48 void set_graphics_mode(const struct multiboot_header *mbh,
49 		       struct multiboot_info *mbi)
50 {
51     com32sys_t rm;
52     uint16_t mode, bestmode, *mode_ptr;
53     struct vesa_general_info *gi;
54     struct vesa_mode_info *mi;
55     int pxf, bestpxf;
56     int wantx, wanty;
57     int err, besterr;
58     bool better;
59     addr_t viaddr;
60 
61     /* Only do this if requested by the OS image */
62     if (!(mbh->flags & MULTIBOOT_VIDEO_MODE) || mbh->mode_type != 0)
63 	return;
64 
65     gi = lmalloc(sizeof *gi);
66     if (!gi)
67 	return;
68 
69     mi = lmalloc(sizeof *mi);
70     if (!mi)
71 	goto out;
72 
73     memset(&rm, 0, sizeof rm);
74     memset(gi, 0, sizeof *gi);
75 
76     gi->signature = VBE2_MAGIC;	/* Get VBE2 extended data */
77     rm.eax.w[0] = 0x4F00;	/* Get SVGA general information */
78     rm.edi.w[0] = OFFS(gi);
79     rm.es = SEG(gi);
80     __intcall(0x10, &rm, &rm);
81 
82     if (rm.eax.w[0] != 0x004F)
83 	goto out;		/* Function call failed */
84     if (gi->signature != VESA_MAGIC)
85 	goto out;		/* No magic */
86     if (gi->version < 0x0102)
87 	goto out;		/* VESA 1.2+ required */
88 
89     memcpy(&vesa_info.gi, gi, sizeof *gi);
90 
91     /* Search for a suitable mode with a suitable color and memory model... */
92 
93     mode_ptr = GET_PTR(gi->video_mode_ptr);
94     bestmode = 0;
95     bestpxf = 0;
96     wantx = mbh->width  ? mbh->width  : 0xffff;
97     wanty = mbh->height ? mbh->height : 0xffff;
98     besterr = wantx + wanty;
99 
100     while ((mode = *mode_ptr++) != 0xFFFF) {
101 	mode &= 0x1FF;		/* The rest are attributes of sorts */
102 
103         memset(&rm, 0, sizeof rm);
104 	memset(mi, 0, sizeof *mi);
105 	rm.eax.w[0] = 0x4F01;	/* Get SVGA mode information */
106 	rm.ecx.w[0] = mode;
107 	rm.edi.w[0] = OFFS(mi);
108 	rm.es = SEG(mi);
109 	__intcall(0x10, &rm, &rm);
110 
111 	/* Must be a supported mode */
112 	if (rm.eax.w[0] != 0x004f)
113 	    continue;
114 
115 	/* Must be an LFB color graphics mode supported by the hardware.
116 
117 	   The bits tested are:
118 	   7 - linear frame buffer
119 	   4 - graphics mode
120 	   3 - color mode
121 	   1 - mode information available (mandatory in VBE 1.2+)
122 	   0 - mode supported by hardware
123 	 */
124 	if ((mi->mode_attr & 0x009b) != 0x009b)
125 	    continue;
126 
127 	/* We don't support multibank (interlaced memory) modes */
128 	/*
129 	 *  Note: The Bochs VESA BIOS (vbe.c 1.58 2006/08/19) violates the
130 	 * specification which states that banks == 1 for unbanked modes;
131 	 * fortunately it does report bank_size == 0 for those.
132 	 */
133 	if (mi->banks > 1 && mi->bank_size)
134 	    continue;
135 
136 	/* Must either be a packed-pixel mode or a direct color mode
137 	   (depending on VESA version ); must be a supported pixel format */
138 
139 	if (mi->bpp == 32 &&
140 	    (mi->memory_layout == 4 ||
141 	     (mi->memory_layout == 6 && mi->rpos == 16 && mi->gpos == 8 &&
142 	      mi->bpos == 0)))
143 	    pxf = 32;
144 	else if (mi->bpp == 24 &&
145 		 (mi->memory_layout == 4 ||
146 		  (mi->memory_layout == 6 && mi->rpos == 16 && mi->gpos == 8 &&
147 		   mi->bpos == 0)))
148 	    pxf = 24;
149 	else if (mi->bpp == 16 &&
150 		 (mi->memory_layout == 4 ||
151 		  (mi->memory_layout == 6 && mi->rpos == 11 && mi->gpos == 5 &&
152 		   mi->bpos == 0)))
153 	    pxf = 16;
154 	else if (mi->bpp == 15 &&
155 		 (mi->memory_layout == 4 ||
156 		  (mi->memory_layout == 6 && mi->rpos == 10 && mi->gpos == 5 &&
157 		   mi->bpos == 0)))
158 	    pxf = 15;
159 	else
160 	    continue;
161 
162 	better = false;
163 	err = abs(mi->h_res - wantx) + abs(mi->v_res - wanty);
164 
165 #define IS_GOOD(mi, bestx, besty) \
166 	((mi)->h_res >= (bestx) && (mi)->v_res >= (besty))
167 
168 	if (!bestpxf)
169 	    better = true;
170 	else if (!IS_GOOD(&vesa_info.mi, wantx, wanty) &&
171 		 IS_GOOD(mi, wantx, wanty))
172 	    /* This matches criteria, which the previous one didn't */
173 	    better = true;
174 	else if (IS_GOOD(&vesa_info.mi, wantx, wanty) &&
175 		 !IS_GOOD(mi, wantx, wanty))
176 	    /* This doesn't match criteria, and the previous one did */
177 	    better = false;
178 	else if (err < besterr)
179 	    better = true;
180 	else if (err == besterr && (pxf == (int)mbh->depth || pxf > bestpxf))
181 	    better = true;
182 
183 	if (better) {
184 	    bestmode = mode;
185 	    bestpxf = pxf;
186 	    memcpy(&vesa_info.mi, mi, sizeof *mi);
187 	}
188     }
189 
190     if (!bestpxf)
191 	goto out;		/* No mode found */
192 
193     mi = &vesa_info.mi;
194     mode = bestmode;
195 
196     /* Now set video mode */
197     memset(&rm, 0, sizeof rm);
198     rm.eax.w[0] = 0x4F02;	/* Set SVGA video mode */
199     mode |= 0x4000;		/* Request linear framebuffer */
200     rm.ebx.w[0] = mode;
201     __intcall(0x10, &rm, &rm);
202     if (rm.eax.w[0] != 0x004F)
203 	goto out;		/* Failed to set mode */
204 
205     mbi->flags |= MB_INFO_VIDEO_INFO;
206     mbi->vbe_mode = mode;
207     viaddr = map_data(&vesa_info, sizeof vesa_info, 4, 0);
208     mbi->vbe_control_info = viaddr + offsetof(struct vesa_info, gi);
209     mbi->vbe_mode_info = viaddr + offsetof(struct vesa_info, mi);
210 
211     /* Get the VBE 2.x PM entry point if supported */
212     rm.eax.w[0] = 0x4F0A;
213     rm.ebx.w[0] = 0;
214     __intcall(0x10, &rm, &rm);
215     if (rm.eax.w[0] == 0x004F) {
216 	mbi->vbe_interface_seg = rm.es;
217 	mbi->vbe_interface_off = rm.edi.w[0];
218 	mbi->vbe_interface_len = rm.ecx.w[0];
219     }
220 
221     /* In theory this should be:
222      *
223      * UsingVga = (mi->mode_attr & 4) ? 0x0007 : 0x000f;
224      *
225      * However, that would assume all systems that claim to handle text
226      * output in VESA modes actually do that...
227      */
228     graphics_using_vga(0x0F, vesa_info.mi.h_res, vesa_info.mi.v_res);
229 
230 out:
231     lfree(mi);
232     lfree(gi);
233 }
234