com32/mboot/initvesa.c

   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
  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(mi, 0, sizeof *mi);
 104         rm.eax.w[0] = 0x4F01;   /* Get SVGA mode information */
 105         rm.ecx.w[0] = mode;
 106         rm.edi.w[0] = OFFS(mi);
 107         rm.es = SEG(mi);
 108         __intcall(0x10, &rm, &rm);
 109
 110         /* Must be a supported mode */
 111         if (rm.eax.w[0] != 0x004f)
 112             continue;
 113
 114         /* Must be an LFB color graphics mode supported by the hardware.
 115
 116            The bits tested are:
 117            7 - linear frame buffer
 118            4 - graphics mode
 119            3 - color mode
 120            1 - mode information available (mandatory in VBE 1.2+)
 121            0 - mode supported by hardware
 122          */
 123         if ((mi->mode_attr & 0x009b) != 0x009b)
 124             continue;
 125
 126         /* We don't support multibank (interlaced memory) modes */
 127         /*
 128          *  Note: The Bochs VESA BIOS (vbe.c 1.58 2006/08/19) violates the
 129          * specification which states that banks == 1 for unbanked modes;
 130          * fortunately it does report bank_size == 0 for those.
 131          */
 132         if (mi->banks > 1 && mi->bank_size)
 133             continue;
 134
 135         /* Must either be a packed-pixel mode or a direct color mode
 136            (depending on VESA version ); must be a supported pixel format */
 137
 138         if (mi->bpp == 32 &&
 139             (mi->memory_layout == 4 ||
 140              (mi->memory_layout == 6 && mi->rpos == 16 && mi->gpos == 8 &&
 141               mi->bpos == 0)))
 142             pxf = 32;
 143         else if (mi->bpp == 24 &&
 144                  (mi->memory_layout == 4 ||
 145                   (mi->memory_layout == 6 && mi->rpos == 16 && mi->gpos == 8 &&
 146                    mi->bpos == 0)))
 147             pxf = 24;
 148         else if (mi->bpp == 16 &&
 149                  (mi->memory_layout == 4 ||
 150                   (mi->memory_layout == 6 && mi->rpos == 11 && mi->gpos == 5 &&
 151                    mi->bpos == 0)))
 152             pxf = 16;
 153         else if (mi->bpp == 15 &&
 154                  (mi->memory_layout == 4 ||
 155                   (mi->memory_layout == 6 && mi->rpos == 10 && mi->gpos == 5 &&
 156                    mi->bpos == 0)))
 157             pxf = 15;
 158         else
 159             continue;
 160
 161         better = false;
 162         err = abs(mi->h_res - wantx) + abs(mi->v_res - wanty);
 163
 164 #define IS_GOOD(mi, bestx, besty) \
 165         ((mi)->h_res >= (bestx) && (mi)->v_res >= (besty))
 166
 167         if (!bestpxf)
 168             better = true;
 169         else if (!IS_GOOD(&vesa_info.mi, wantx, wanty) &&
 170                  IS_GOOD(mi, wantx, wanty))
 171             /* This matches criteria, which the previous one didn't */
 172             better = true;
 173         else if (IS_GOOD(&vesa_info.mi, wantx, wanty) &&
 174                  !IS_GOOD(mi, wantx, wanty))
 175             /* This doesn't match criteria, and the previous one did */
 176             better = false;
 177         else if (err < besterr)
 178             better = true;
 179         else if (err == besterr && (pxf == (int)mbh->depth || pxf > bestpxf))
 180             better = true;
 181
 182         if (better) {
 183             bestmode = mode;
 184             bestpxf = pxf;
 185             memcpy(&vesa_info.mi, mi, sizeof *mi);
 186         }
 187     }
 188
 189     if (!bestpxf)
 190         goto out;               /* No mode found */
 191
 192     mi = &vesa_info.mi;
 193     mode = bestmode;
 194
 195     /* Now set video mode */
 196     rm.eax.w[0] = 0x4F02;       /* Set SVGA video mode */
 197     mode |= 0x4000;             /* Request linear framebuffer */
 198     rm.ebx.w[0] = mode;
 199     __intcall(0x10, &rm, &rm);
 200     if (rm.eax.w[0] != 0x004F)
 201         goto out;               /* Failed to set mode */
 202
 203     mbi->flags |= MB_INFO_VIDEO_INFO;
 204     mbi->vbe_mode = mode;
 205     viaddr = map_data(&vesa_info, sizeof vesa_info, 4, 0);
 206     mbi->vbe_control_info = viaddr + offsetof(struct vesa_info, gi);
 207     mbi->vbe_mode_info = viaddr + offsetof(struct vesa_info, mi);
 208
 209     /* Get the VBE 2.x PM entry point if supported */
 210     rm.eax.w[0] = 0x4F0A;
 211     rm.ebx.w[0] = 0;
 212     __intcall(0x10, &rm, &rm);
 213     if (rm.eax.w[0] == 0x004F) {
 214         mbi->vbe_interface_seg = rm.es;
 215         mbi->vbe_interface_off = rm.edi.w[0];
 216         mbi->vbe_interface_len = rm.ecx.w[0];
 217     }
 218
 219     /* In theory this should be:
 220      *
 221      * UsingVga = (mi->mode_attr & 4) ? 0x0007 : 0x000f;
 222      *
 223      * However, that would assume all systems that claim to handle text
 224      * output in VESA modes actually do that...
 225      */
 226     graphics_using_vga(0x0F, vesa_info.mi.h_res, vesa_info.mi.v_res);
 227
 228 out:
 229     lfree(mi);
 230     lfree(gi);
 231 }