src/northbridge/via/cx700/vgabios.c

   1 /*
   2  * This file is part of the coreboot project.
   3  *
   4  * (C) 2007-2009 coresystems GmbH
   5  * (See further copyright notices below)
   6  *
   7  * NOTE: This file is supposed to go away once the generic vm86 handler
   8  * in util/x86emu is able to handle intXX hooks like yabel does.
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; version 2 of the License.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  22  */
  23
  24 #include <console/console.h>
  25 #include <device/pci.h>
  26 #include <device/pci_ids.h>
  27 #include <device/pci_ops.h>
  28 #undef __KERNEL__
  29 #include <arch/io.h>
  30 #include <string.h>
  31 #include <cbfs.h>
  32
  33 void write_protect_vgabios(void);
  34
  35 /* vgabios.c. Derived from: */
  36
  37 /*------------------------------------------------------------ -*- C -*-
  38  *  2 Kernel Monte a.k.a. Linux loading Linux on x86
  39  *
  40  *  Erik Arjan Hendriks <hendriks@lanl.gov>
  41  *
  42  *  This version is a derivative of the original two kernel monte
  43  *  which is (C) 2000 Scyld.
  44  *
  45  *  Copyright (C) 2000 Scyld Computing Corporation
  46  *
  47  * Portions related to the alpha architecture are:
  48  *
  49  *  Copyright(C) 2001 University of California.  LA-CC Number 01-67.
  50  *  This software has been authored by an employee or employees of the
  51  *  University of California, operator of the Los Alamos National
  52  *  Laboratory under Contract No.  W-7405-ENG-36 with the U.S.
  53  *  Department of Energy.  The U.S. Government has rights to use,
  54  *  reproduce, and distribute this software. If the software is
  55  *  modified to produce derivative works, such modified software should
  56  *  be clearly marked, so as not to confuse it with the version
  57  *  available from LANL.
  58  *
  59  *  This software may be used and distributed according to the terms
  60  *  of the GNU General Public License, incorporated herein by
  61  *  reference to http://www.gnu.org/licenses/gpl.html.
  62  *
  63  *  This software is provided by the author(s) "as is" and any express
  64  *  or implied warranties, including, but not limited to, the implied
  65  *  warranties of merchantability and fitness for a particular purpose
  66  *  are disclaimed.  In no event shall the author(s) be liable for any
  67  *  direct, indirect, incidental, special, exemplary, or consequential
  68  *  damages (including, but not limited to, procurement of substitute
  69  *  goods or services; loss of use, data, or profits; or business
  70  *  interruption) however caused and on any theory of liability,
  71  *  whether in contract, strict liability, or tort (including
  72  *  negligence or otherwise) arising in any way out of the use of this
  73  *  software, even if advised of the possibility of such damage.
  74  *
  75  *--------------------------------------------------------------------*/
  76
  77 /* Modified to be a self sufficient plug in so that it can be used
  78    without reliance on other parts of core Linuxbios
  79    (C) 2005 Nick.Barker9@btinternet.com
  80
  81   Used initially for epia-m where there are problems getting the bios
  82   emulator to successfully run this bios.
  83 */
  84
  85 /* Declare a temporary global descriptor table - necessary because the
  86    Core part of the bios no longer sets up any 16 bit segments */
  87 __asm__(
  88                /* pointer to original gdt */
  89                "gdtarg:                 \n"
  90                "        .word   gdt_limit       \n"
  91                "        .long   gdt             \n"
  92                /* compute the table limit */
  93                "__mygdt_limit = __mygdt_end - __mygdt - 1       \n"
  94                "__mygdtaddr:                    \n"
  95                "        .word   __mygdt_limit   \n"
  96                "        .long   __mygdt         \n"
  97                "__mygdt:                        \n"
  98                /* selgdt 0, unused */
  99                "        .word   0x0000, 0x0000  \n"
 100                "        .byte   0x00, 0x00, 0x00, 0x00  \n"
 101                /* selgdt 8, unused */
 102                "        .word   0x0000, 0x0000          \n"
 103                "        .byte   0x00, 0x00, 0x00, 0x00  \n"
 104                /* selgdt 0x10, flat code segment */
 105                "        .word   0xffff, 0x0000          \n"
 106                "        .byte   0x00, 0x9b, 0xcf, 0x00  \n"
 107                /* selgdt 0x18, flat data segment */
 108                "        .word   0xffff, 0x0000          \n"
 109                "        .byte   0x00, 0x93, 0xcf, 0x00  \n"
 110                /* selgdt 0x20, unused */
 111                "        .word   0x0000, 0x0000          \n"
 112                "        .byte   0x00, 0x00, 0x00, 0x00  \n"
 113                /* selgdt 0x28 16-bit 64k code at 0x00000000 */
 114                "        .word   0xffff, 0x0000          \n"
 115                "        .byte   0, 0x9a, 0, 0           \n"
 116                /* selgdt 0x30 16-bit 64k data at 0x00000000 */
 117                "        .word   0xffff, 0x0000          \n"
 118                "        .byte   0, 0x92, 0, 0           \n"
 119                "__mygdt_end:                            \n");
 120
 121 /* Declare a pointer to where our idt is going to be i.e. at mem zero */
 122 __asm__("__myidt:               \n"
 123         /* 16-bit limit */
 124         "       .word 1023      \n"
 125         /* 24-bit base */
 126         "       .long 0         \n" "   .word 0         \n");
 127
 128 /* The address arguments to this function are PHYSICAL ADDRESSES */
 129 static void real_mode_switch_call_vga(unsigned long devfn)
 130 {
 131         __asm__ __volatile__(
 132                                     // paranoia -- does ecx get saved? not sure. This is
 133                                     // the easiest safe thing to do.
 134                                     "   pushal                  \n"
 135                                     /* save the stack */
 136                                     "   mov     %esp, __stack   \n"
 137                                     "   jmp     1f              \n"
 138                                     "__stack: .long 0           \n" "1:\n"
 139                                     /* get devfn into %ecx */
 140                                     "   movl    %esp, %ebp      \n"
 141                                     "   movl    8(%ebp), %ecx   \n"
 142                                     /* load 'our' gdt */
 143                                     "   lgdt    %cs:__mygdtaddr \n"
 144                                     /*  This configures CS properly for real mode. */
 145                                     "   ljmp    $0x28, $__rms_16bit\n"
 146                                     "__rms_16bit:                       \n"
 147                                     "   .code16                 \n"
 148                                     /* 16 bit code from here on... */
 149                                     /* Load the segment registers w/ properly configured segment
 150                                      * descriptors.  They will retain these configurations (limits,
 151                                      * writability, etc.) once protected mode is turned off. */
 152                                     "   mov     $0x30, %ax      \n"
 153                                     "   mov     %ax, %ds        \n"
 154                                     "   mov     %ax, %es        \n"
 155                                     "   mov     %ax, %fs        \n"
 156                                     "   mov     %ax, %gs        \n"
 157                                     "   mov     %ax, %ss        \n"
 158                                     /* Turn off protection (bit 0 in CR0) */
 159                                     "   movl    %cr0, %eax      \n"
 160                                     "   andl    $0xFFFFFFFE, %eax \n"
 161                                     "   movl    %eax, %cr0      \n"
 162                                     /* Now really going into real mode */
 163                                     "   ljmp    $0,  $__rms_real\n"
 164                                     "__rms_real:                        \n"
 165                                     /* put the stack at the end of page zero.
 166                                      * that way we can easily share it between real and protected,
 167                                      * since the 16-bit ESP at segment 0 will work for any case.
 168                                      */
 169                                     /* Setup a stack */
 170                                     "   mov     $0x0, %ax       \n"
 171                                     "   mov     %ax, %ss        \n"
 172                                     "   movl    $0x1000, %eax   \n"
 173                                     "   movl    %eax, %esp      \n"
 174                                     /* Load our 16 it idt */
 175                                     "   xor     %ax, %ax        \n"
 176                                     "   mov     %ax, %ds        \n"
 177                                     "   lidt    __myidt         \n"
 178                                     /* Dump zeros in the other segregs */
 179                                     "   mov     %ax, %es        \n"
 180                                     "   mov     %ax, %fs        \n"
 181                                     "   mov     %ax, %gs        \n"
 182                                     "   mov     $0x40, %ax      \n"
 183                                     "   mov     %ax, %ds        \n"
 184                                     "   mov     %cx, %ax        \n"
 185                                     /* run VGA BIOS at 0xc000:0003 */
 186                                     "   lcall   $0xc000, $0x0003\n"
 187                                     /* if we got here, just about done.
 188                                      * Need to get back to protected mode */
 189                                     "   movl    %cr0, %eax      \n" "   orl     $0x0000001, %eax\n"     /* PE = 1 */
 190                                     "   movl    %eax, %cr0      \n"
 191                                     /* Now that we are in protected mode jump to a 32 bit code segment. */
 192                                     "   data32  ljmp    $0x10, $vgarestart\n"
 193                                     "vgarestart:\n"
 194                                     "   .code32\n"
 195                                     "   movw    $0x18, %ax      \n"
 196                                     "   mov     %ax, %ds        \n"
 197                                     "   mov     %ax, %es        \n"
 198                                     "   mov     %ax, %fs        \n"
 199                                     "   mov     %ax, %gs        \n"
 200                                     "   mov     %ax, %ss        \n"
 201                                     /* restore proper gdt and idt */
 202                                     "   lgdt    %cs:gdtarg      \n"
 203                                     "   lidt    idtarg          \n"
 204                                     ".globl vga_exit            \n"
 205                                     "vga_exit:                  \n"
 206                                     "   mov     __stack, %esp   \n"
 207                                     "   popal                   \n");
 208 }
 209
 210 __asm__(".text\n" "real_mode_switch_end:\n");
 211 extern char real_mode_switch_end[];
 212
 213 /* call vga bios int 10 function 0x4f14 to enable main console
 214    epia-m does not always autosence the main console so forcing it on is good !! */
 215 void vga_enable_console(void)
 216 {
 217         __asm__ __volatile__(
 218                                     /* paranoia -- does ecx get saved? not sure. This is
 219                                      * the easiest safe thing to do. */
 220                                     "   pushal                  \n"
 221                                     /* save the stack */
 222                                     "   mov     %esp, __stack   \n"
 223                                     /* load 'our' gdt */
 224                                     "   lgdt    %cs:__mygdtaddr \n"
 225                                     /*  This configures CS properly for real mode. */
 226                                     "   ljmp    $0x28, $__vga_ec_16bit\n"
 227                                     "__vga_ec_16bit:            \n"
 228                                     "   .code16                 \n"
 229                                     /* 16 bit code from here on... */
 230                                     /* Load the segment registers w/ properly configured segment
 231                                      * descriptors.  They will retain these configurations (limits,
 232                                      * writability, etc.) once protected mode is turned off. */
 233                                     "   mov     $0x30, %ax      \n"
 234                                     "   mov     %ax, %ds        \n"
 235                                     "   mov     %ax, %es        \n"
 236                                     "   mov     %ax, %fs        \n"
 237                                     "   mov     %ax, %gs        \n"
 238                                     "   mov     %ax, %ss        \n"
 239                                     /* Turn off protection (bit 0 in CR0) */
 240                                     "   movl    %cr0, %eax      \n"
 241                                     "   andl    $0xFFFFFFFE, %eax\n"
 242                                     "   movl    %eax, %cr0      \n"
 243                                     /* Now really going into real mode */
 244                                     "   ljmp    $0, $__vga_ec_real \n"
 245                                     "__vga_ec_real:                  \n"
 246                                     /* put the stack at the end of page zero.
 247                                      * that way we can easily share it between real and protected,
 248                                      * since the 16-bit ESP at segment 0 will work for any case.
 249                                      */
 250                                     /* Setup a stack */
 251                                     "   mov     $0x0, %ax       \n"
 252                                     "   mov     %ax, %ss        \n"
 253                                     "   movl    $0x1000, %eax   \n"
 254                                     "   movl    %eax, %esp      \n"
 255                                     /* debugging for RGM */
 256                                     "   mov     $0x11, %al      \n"
 257                                     "   outb    %al, $0x80      \n"
 258                                     /* Load our 16 it idt */
 259                                     "   xor     %ax, %ax        \n"
 260                                     "   mov     %ax, %ds        \n"
 261                                     "   lidt    __myidt         \n"
 262                                     /* Dump zeros in the other segregs */
 263                                     "   mov     %ax, %ds        \n"
 264                                     "   mov     %ax, %es        \n"
 265                                     "   mov     %ax, %fs        \n"
 266                                     "   mov     %ax, %gs        \n"
 267                                     /* ask bios to enable main console */
 268                                     /* set up for int 10 call - values found from X server
 269                                      * bios call routines */
 270                                     "   movw    $0x4f14,%ax     \n"
 271                                     "   movw    $0x8003,%bx     \n"
 272                                     "   movw    $1, %cx         \n"
 273                                     "   movw    $0, %dx         \n"
 274                                     "   movw    $0, %di         \n"
 275                                     "   int     $0x10           \n"
 276                                     "   movb    $0x55, %al      \n"
 277                                     "   outb    %al, $0x80      \n"
 278                                     /* if we got here, just about done.
 279                                      * Need to get back to protected mode */
 280                                     "   movl    %cr0, %eax      \n" "   orl     $0x0000001, %eax\n"     /* PE = 1 */
 281                                     "   movl    %eax, %cr0      \n"
 282                                     /* Now that we are in protected mode jump to a 32 bit code segment. */
 283                                     "   data32  ljmp    $0x10, $vga_ec_restart\n"
 284                                     "vga_ec_restart:\n"
 285                                     "   .code32\n"
 286                                     "   movw    $0x18, %ax      \n"
 287                                     "   mov     %ax, %ds        \n"
 288                                     "   mov     %ax, %es        \n"
 289                                     "   mov     %ax, %fs        \n"
 290                                     "   mov     %ax, %gs        \n"
 291                                     "   mov     %ax, %ss        \n"
 292                                     /* restore proper gdt and idt */
 293                                     "   lgdt    %cs:gdtarg      \n"
 294                                     "   lidt    idtarg          \n"
 295                                     "   .globl  vga__ec_exit    \n"
 296                                     "vga_ec_exit:\n"
 297                                     "   mov     __stack, %esp   \n"
 298                                     "   popal\n");
 299 }
 300
 301 void do_vgabios(void)
 302 {
 303         device_t dev;
 304         unsigned long busdevfn;
 305         unsigned int rom = 0;
 306         unsigned char *buf;
 307         unsigned int size = 64 * 1024;
 308         int i;
 309
 310         /* clear vga bios data area */
 311         for (i = 0x400; i < 0x500; i++) {
 312                 *(unsigned char *)i = 0;
 313         }
 314
 315         dev = dev_find_class(PCI_CLASS_DISPLAY_VGA << 8, 0);
 316
 317         if (!dev) {
 318                 printk(BIOS_DEBUG, "NO VGA FOUND\n");
 319                 return;
 320         }
 321         printk(BIOS_DEBUG, "found VGA: vid=%x, did=%x\n", dev->vendor, dev->device);
 322
 323         /* declare rom address here - keep any config data out of the way
 324          * of core LXB stuff */
 325
 326 #warning ROM address hardcoded to 512K
 327         rom = (unsigned int)cbfs_load_optionrom(dev->vendor, dev->device, 0);
 328         pci_write_config32(dev, PCI_ROM_ADDRESS, rom | 1);
 329         printk(BIOS_DEBUG, "rom base, size: %x\n", rom);
 330
 331         buf = (unsigned char *)rom;
 332         if ((buf[0] == 0x55) && (buf[1] == 0xaa)) {
 333                 memcpy((void *)0xc0000, buf, size);
 334
 335                 write_protect_vgabios();        // in northbridge
 336
 337                 // check signature again
 338                 buf = (unsigned char *)0xc0000;
 339                 if (buf[0] == 0x55 && buf[1] == 0xAA) {
 340                         busdevfn =
 341                             (dev->bus->secondary << 8) | dev->path.pci.devfn;
 342                         printk(BIOS_DEBUG, "bus/devfn = %#lx\n", busdevfn);
 343
 344                         real_mode_switch_call_vga(busdevfn);
 345                 } else
 346                         printk(BIOS_DEBUG, "Failed to copy VGA BIOS to 0xc0000\n");
 347         } else
 348                 printk(BIOS_DEBUG, "BAD SIGNATURE 0x%x 0x%x\n", buf[0], buf[1]);
 349
 350         pci_write_config32(dev, PCI_ROM_ADDRESS, 0);
 351 }
 352
 353 // we had hoped to avoid this.
 354 // this is a stub IDT only. It's main purpose is to ignore calls
 355 // to the BIOS.
 356 // no longer. Dammit. We have to respond to these.
 357 struct realidt {
 358         unsigned short offset, cs;
 359 };
 360
 361 // from a handy writeup that andrey found.
 362
 363 // handler.
 364 // There are some assumptions we can make here.
 365 // First, the Top Of Stack (TOS) is located on the top of page zero.
 366 // we can share this stack between real and protected mode.
 367 // that simplifies a lot of things ...
 368 // we'll just push all the registers on the stack as longwords,
 369 // and pop to protected mode.
 370 // second, since this only ever runs as part of linuxbios,
 371 // we know all the segment register values -- so we don't save any.
 372 // keep the handler that calls things small. It can do a call to
 373 // more complex code in linuxbios itself. This helps a lot as we don't
 374 // have to do address fixup in this little stub, and calls are absolute
 375 // so the handler is relocatable.
 376 void handler(void)
 377 {
 378         __asm__ __volatile__("  .code16         \n"
 379                              "idthandle:                \n"
 380                              "  pushal          \n"
 381                              "  movb    $0, %al \n"
 382                              "  ljmp    $0, $callbiosint16\n"
 383                              "end_idthandle:            \n"
 384                              "  .code32         \n");
 385 }
 386
 387 void debughandler(void)
 388 {
 389         __asm__ __volatile__("  .code16         \n"
 390                              "debughandle:              \n"
 391                              "  pushw   %cx     \n"
 392                              "  movw    $250, %cx \n"
 393                              "dbh1:                     \n"
 394                              "  loop    dbh1    \n"
 395                              "  popw    %cx     \n"
 396                              "  iret            \n"
 397                              "end_debughandle:  \n" ".code32            \n");
 398 }
 399
 400 // Calling conventions. The first C function is called with this stuff
 401 // on the stack. They look like value parameters, but note that if you
 402 // modify them they will go back to the INTx function modified.
 403 // the C function will call the biosint function with these as
 404 // REFERENCE parameters. In this way, we can easily get
 405 // returns back to the INTx caller (i.e. vgabios)
 406 void callbiosint(void)
 407 {
 408         __asm__ __volatile__("  .code16         \n"
 409                              "callbiosint16:            \n"
 410                              "  push    %ds     \n"
 411                              "  push    %es     \n"
 412                              "  push    %fs     \n" "   push    %gs     \n"
 413                              // clean up the int #. To save space we put it in the lower
 414                              // byte. But the top 24 bits are junk.
 415                              "  andl    $0xff, %eax\n"
 416                              // this push does two things:
 417                              // - put the INT # on the stack as a parameter
 418                              // - provides us with a temp for the %cr0 mods.
 419                              "  pushl   %eax    \n" "   movl    %cr0, %eax\n" " orl     $0x00000001, %eax\n"    /* PE = 1 */
 420                              "  movl    %eax, %cr0\n"
 421                              /* Now that we are in protected mode jump to a 32 bit code segment. */
 422                              "  data32  ljmp    $0x10, $biosprotect\n"
 423                              "biosprotect:              \n"
 424                              "  .code32         \n"
 425                              "  movw    $0x18, %ax          \n"
 426                              "  mov     %ax, %ds          \n"
 427                              "  mov     %ax, %es          \n"
 428                              "  mov     %ax, %fs          \n"
 429                              "  mov     %ax, %gs          \n"
 430                              "  mov     %ax, %ss          \n"
 431                              "  lidt    idtarg         \n"
 432                              "  call    biosint \n"
 433                              // back to real mode ...
 434                              "  ljmp    $0x28, $__rms_16bit2\n"
 435                              "__rms_16bit2:                     \n"
 436                              "  .code16                 \n"
 437                              /* 16 bit code from here on... */
 438                              /* Load the segment registers w/ properly configured segment
 439                               * descriptors.  They will retain these configurations (limits,
 440                               * writability, etc.) once protected mode is turned off. */
 441                              "  mov     $0x30, %ax      \n"
 442                              "  mov     %ax, %ds        \n"
 443                              "  mov     %ax, %es        \n"
 444                              "  mov     %ax, %fs        \n"
 445                              "  mov     %ax, %gs        \n"
 446                              "  mov     %ax, %ss        \n"
 447                              /* Turn off protection (bit 0 in CR0) */
 448                              "  movl    %cr0, %eax              \n"
 449                              "  andl    $0xFFFFFFFE, %eax       \n"
 450                              "  movl    %eax, %cr0              \n"
 451                              /* Now really going into real mode */
 452                              "  ljmp $0,  $__rms_real2  \n"
 453                              "__rms_real2:                      \n"
 454                              /* Setup a stack
 455                               * FixME: where is esp? */
 456                              "  mov     $0x0, %ax       \n"
 457                              "  mov     %ax, %ss        \n"
 458                              /* ebugging for RGM */
 459                              "  mov     $0x11, %al      \n"
 460                              "  outb    %al, $0x80      \n"
 461                              /* Load our 16 it idt */
 462                              "  xor     %ax, %ax        \n"
 463                              "  mov     %ax, %ds        \n"
 464                              "  lidt    __myidt         \n"
 465                              /* Dump zeros in the other segregs */
 466                              "  mov     %ax, %es        \n"
 467                              "  mov     %ax, %fs        \n"
 468                              "  mov     %ax, %gs        \n"
 469                              "  mov     $0x40, %ax      \n"
 470                              "  mov     %ax, %ds        \n"
 471                              /* pop the INT # that you pushed earlier */
 472                              "  popl    %eax            \n"
 473                              "  pop     %gs             \n"
 474                              "  pop     %fs             \n"
 475                              "  pop     %es             \n"
 476                              "  pop     %ds             \n"
 477                              "  popal                   \n"
 478                              "  iret                    \n"
 479                              "  .code32                 \n");
 480 }
 481
 482 enum {
 483         PCIBIOS = 0x1a,
 484         MEMSIZE = 0x12
 485 };
 486
 487 int pcibios(unsigned long *pedi, unsigned long *pesi, unsigned long *pebp,
 488             unsigned long *pesp, unsigned long *pebx, unsigned long *pedx,
 489             unsigned long *pecx, unsigned long *peax, unsigned long *pflags);
 490
 491 int handleint21(unsigned long *pedi, unsigned long *pesi, unsigned long *pebp,
 492                 unsigned long *pesp, unsigned long *pebx, unsigned long *pedx,
 493                 unsigned long *pecx, unsigned long *peax,
 494                 unsigned long *pflags);
 495
 496 extern void vga_exit(void);
 497
 498 int biosint(unsigned long intnumber,
 499             unsigned long gsfs, unsigned long dses,
 500             unsigned long edi, unsigned long esi,
 501             unsigned long ebp, unsigned long esp,
 502             unsigned long ebx, unsigned long edx,
 503             unsigned long ecx, unsigned long eax,
 504             unsigned long cs_ip, unsigned short stackflags)
 505 {
 506         unsigned long ip;
 507         unsigned long cs;
 508         unsigned long flags;
 509         int ret = -1;
 510
 511         ip = cs_ip & 0xffff;
 512         cs = cs_ip >> 16;
 513         flags = stackflags;
 514
 515         printk(BIOS_DEBUG, "biosint: INT# 0x%lx\n", intnumber);
 516         printk(BIOS_DEBUG, "biosint: eax 0x%lx ebx 0x%lx ecx 0x%lx edx 0x%lx\n",
 517                      eax, ebx, ecx, edx);
 518         printk(BIOS_DEBUG, "biosint: ebp 0x%lx esp 0x%lx edi 0x%lx esi 0x%lx\n",
 519                      ebp, esp, edi, esi);
 520         printk(BIOS_DEBUG, "biosint:  ip 0x%lx   cs 0x%lx  flags 0x%lx\n",
 521                      ip, cs, flags);
 522
 523         // cases in a good compiler are just as good as your own tables.
 524         switch (intnumber) {
 525         case 0 ... 15:
 526                 // These are not BIOS service, but the CPU-generated exceptions
 527                 printk(BIOS_INFO, "biosint: Oops, exception %lu\n", intnumber);
 528                 if (esp < 0x1000) {
 529                         printk(BIOS_DEBUG, "Stack contents: ");
 530                         while (esp < 0x1000) {
 531                                 printk(BIOS_DEBUG, "0x%04x ", *(unsigned short *)esp);
 532                                 esp += 2;
 533                         }
 534                         printk(BIOS_DEBUG, "\n");
 535                 }
 536                 printk(BIOS_DEBUG, "biosint: Bailing out\n");
 537                 // "longjmp"
 538                 vga_exit();
 539                 break;
 540
 541         case PCIBIOS:
 542                 ret = pcibios(&edi, &esi, &ebp, &esp,
 543                               &ebx, &edx, &ecx, &eax, &flags);
 544                 break;
 545         case MEMSIZE:
 546                 // who cares.
 547                 eax = 64 * 1024;
 548                 ret = 0;
 549                 break;
 550         case 0x15:
 551                 ret = handleint21(&edi, &esi, &ebp, &esp,
 552                                   &ebx, &edx, &ecx, &eax, &flags);
 553                 break;
 554         default:
 555                 printk(BIOS_INFO, "BIOSINT: Unsupport int #0x%lx\n", intnumber);
 556                 break;
 557         }
 558         if (ret)
 559                 flags |= 1;     // carry flags
 560         else
 561                 flags &= ~1;
 562         stackflags = flags;
 563         return ret;
 564 }
 565
 566 void setup_realmode_idt(void)
 567 {
 568         extern unsigned char idthandle, end_idthandle;
 569         extern unsigned char debughandle, end_debughandle;
 570
 571         int i;
 572         struct realidt *idts = (struct realidt *)0;
 573         int codesize = &end_idthandle - &idthandle;
 574         unsigned char *intbyte, *codeptr;
 575
 576         // for each int, we create a customized little handler
 577         // that just pushes %ax, puts the int # in %al,
 578         // then calls the common interrupt handler.
 579         // this necessitated because intel didn't know much about
 580         // architecture when they did the 8086 (it shows)
 581         // (hmm do they know anymore even now :-)
 582         // obviously you can see I don't really care about memory
 583         // efficiency. If I did I would probe back through the stack
 584         // and get it that way. But that's really disgusting.
 585         for (i = 0; i < 256; i++) {
 586                 idts[i].cs = 0;
 587                 codeptr = (unsigned char *)4096 + i * codesize;
 588                 idts[i].offset = (unsigned)codeptr;
 589                 memcpy(codeptr, &idthandle, codesize);
 590                 intbyte = codeptr + 3;
 591                 *intbyte = i;
 592         }
 593
 594         // fixed entry points
 595
 596         // VGA BIOSes tend to hardcode f000:f065 as the previous handler of
 597         // int10.
 598         // calling convention here is the same as INTs, we can reuse
 599         // the int entry code.
 600         codeptr = (unsigned char *)0xff065;
 601         memcpy(codeptr, &idthandle, codesize);
 602         intbyte = codeptr + 3;
 603         *intbyte = 0x42;        /* int42 is the relocated int10 */
 604
 605         // VIA's VBIOS will call f000:f859 instead of sending int15.
 606         codeptr = (unsigned char *)0xff859;
 607         memcpy(codeptr, &idthandle, codesize);
 608         intbyte = codeptr + 3;
 609         *intbyte = 0x15;
 610
 611         /* debug handler - useful to set a programmable delay between instructions if the
 612            TF bit is set upon call to real mode */
 613         idts[1].cs = 0;
 614         idts[1].offset = 16384;
 615         memcpy((void *)16384UL, &debughandle, &end_debughandle - &debughandle);
 616 }
 617
 618 enum {
 619         CHECK = 0xb001,
 620         FINDDEV = 0xb102,
 621         READCONFBYTE = 0xb108,
 622         READCONFWORD = 0xb109,
 623         READCONFDWORD = 0xb10a,
 624         WRITECONFBYTE = 0xb10b,
 625         WRITECONFWORD = 0xb10c,
 626         WRITECONFDWORD = 0xb10d
 627 };
 628
 629 // errors go in AH. Just set these up so that word assigns
 630 // will work. KISS.
 631 enum {
 632         PCIBIOS_NODEV = 0x8600,
 633         PCIBIOS_BADREG = 0x8700
 634 };
 635
 636 int
 637 pcibios(unsigned long *pedi, unsigned long *pesi, unsigned long *pebp,
 638         unsigned long *pesp, unsigned long *pebx, unsigned long *pedx,
 639         unsigned long *pecx, unsigned long *peax, unsigned long *pflags)
 640 {
 641         unsigned short func = (unsigned short)(*peax);
 642         int retval = 0;
 643         unsigned short devid, vendorid, devfn;
 644         short devindex;         /* Use short to get rid of garbage in upper half of 32-bit register */
 645         unsigned char bus;
 646         device_t dev;
 647
 648         switch (func) {
 649         case CHECK:
 650                 *pedx = 0x4350;
 651                 *pecx = 0x2049;
 652                 retval = 0;
 653                 break;
 654         case FINDDEV:
 655                 {
 656                         devid = *pecx;
 657                         vendorid = *pedx;
 658                         devindex = *pesi;
 659                         dev = 0;
 660                         while ((dev = dev_find_device(vendorid, devid, dev))) {
 661                                 if (devindex <= 0)
 662                                         break;
 663                                 devindex--;
 664                         }
 665                         if (dev) {
 666                                 unsigned short busdevfn;
 667                                 *peax = 0;
 668                                 // busnum is an unsigned char;
 669                                 // devfn is an int, so we mask it off.
 670                                 busdevfn = (dev->bus->secondary << 8)
 671                                     | (dev->path.pci.devfn & 0xff);
 672                                 printk(BIOS_DEBUG, "0x%x: return 0x%x\n", func,
 673                                              busdevfn);
 674                                 *pebx = busdevfn;
 675                                 retval = 0;
 676                         } else {
 677                                 *peax = PCIBIOS_NODEV;
 678                                 retval = -1;
 679                         }
 680                 }
 681                 break;
 682         case READCONFDWORD:
 683         case READCONFWORD:
 684         case READCONFBYTE:
 685         case WRITECONFDWORD:
 686         case WRITECONFWORD:
 687         case WRITECONFBYTE:
 688                 {
 689                         unsigned long dword;
 690                         unsigned short word;
 691                         unsigned char byte;
 692                         unsigned char reg;
 693
 694                         devfn = *pebx & 0xff;
 695                         bus = *pebx >> 8;
 696                         reg = *pedi;
 697                         dev = dev_find_slot(bus, devfn);
 698                         if (!dev) {
 699                                 printk(BIOS_DEBUG, "0x%x: BAD DEVICE bus %d devfn 0x%x\n",
 700                                      func, bus, devfn);
 701                                 // idiots. the pcibios guys assumed you'd never pass a bad bus/devfn!
 702                                 *peax = PCIBIOS_BADREG;
 703                                 retval = -1;
 704                         }
 705                         switch (func) {
 706                         case READCONFBYTE:
 707                                 byte = pci_read_config8(dev, reg);
 708                                 *pecx = byte;
 709                                 break;
 710                         case READCONFWORD:
 711                                 word = pci_read_config16(dev, reg);
 712                                 *pecx = word;
 713                                 break;
 714                         case READCONFDWORD:
 715                                 dword = pci_read_config32(dev, reg);
 716                                 *pecx = dword;
 717                                 break;
 718                         case WRITECONFBYTE:
 719                                 byte = *pecx;
 720                                 pci_write_config8(dev, reg, byte);
 721                                 break;
 722                         case WRITECONFWORD:
 723                                 word = *pecx;
 724                                 pci_write_config16(dev, reg, word);
 725                                 break;
 726                         case WRITECONFDWORD:
 727                                 dword = *pecx;
 728                                 pci_write_config32(dev, reg, dword);
 729                                 break;
 730                         }
 731
 732                         if (retval)
 733                                 retval = PCIBIOS_BADREG;
 734                         printk(BIOS_DEBUG, "0x%x: bus %d devfn 0x%x reg 0x%x val 0x%lx\n",
 735                              func, bus, devfn, reg, *pecx);
 736                         *peax = 0;
 737                         retval = 0;
 738                 }
 739                 break;
 740         default:
 741                 printk(BIOS_ERR, "UNSUPPORTED PCIBIOS FUNCTION 0x%x\n", func);
 742                 break;
 743         }
 744
 745         return retval;
 746 }
 747
 748 int handleint21(unsigned long *edi, unsigned long *esi, unsigned long *ebp,
 749                 unsigned long *esp, unsigned long *ebx, unsigned long *edx,
 750                 unsigned long *ecx, unsigned long *eax, unsigned long *flags)
 751 {
 752         int res = -1;
 753         switch (*eax & 0xffff) {
 754         case 0x5f19:
 755                 break;
 756         case 0x5f18:
 757                 *eax = 0x5f;
 758                 *ebx = 0x545;   // MCLK = 133, 32M frame buffer, 256 M main memory
 759                 *ecx = 0x060;
 760                 res = 0;
 761                 break;
 762         case 0x5f00:
 763                 *eax = 0x8600;
 764                 break;
 765         case 0x5f01:
 766                 *eax = 0x5f;
 767                 *ecx = (*ecx & 0xffffff00) | 2; // panel type =  2 = 1024 * 768
 768                 res = 0;
 769                 break;
 770         case 0x5f02:
 771                 *eax = 0x5f;
 772                 *ebx = (*ebx & 0xffff0000) | 2;
 773                 *ecx = (*ecx & 0xffff0000) | 0x401;     // PAL + crt only
 774                 *edx = (*edx & 0xffff0000) | 0; // TV Layout - default
 775                 res = 0;
 776                 break;
 777         case 0x5f0f:
 778                 *eax = 0x860f;
 779                 break;
 780         }
 781         return res;
 782 }