arch/x86/lib/bios.c

   1 /*
   2  * From Coreboot file device/oprom/realmode/x86.c
   3  *
   4  * Copyright (C) 2007 Advanced Micro Devices, Inc.
   5  * Copyright (C) 2009-2010 coresystems GmbH
   6  *
   7  * SPDX-License-Identifier:     GPL-2.0
   8  */
   9 #include <common.h>
  10 #include <bios_emul.h>
  11 #include <vbe.h>
  12 #include <linux/linkage.h>
  13 #include <asm/cache.h>
  14 #include <asm/processor.h>
  15 #include <asm/i8259.h>
  16 #include <asm/io.h>
  17 #include <asm/post.h>
  18 #include "bios.h"
  19
  20 /* Interrupt handlers for each interrupt the ROM can call */
  21 static int (*int_handler[256])(void);
  22
  23 /* to have a common register file for interrupt handlers */
  24 X86EMU_sysEnv _X86EMU_env;
  25
  26 asmlinkage void (*realmode_call)(u32 addr, u32 eax, u32 ebx, u32 ecx, u32 edx,
  27                                  u32 esi, u32 edi);
  28
  29 asmlinkage void (*realmode_interrupt)(u32 intno, u32 eax, u32 ebx, u32 ecx,
  30                                       u32 edx, u32 esi, u32 edi);
  31
  32 static void setup_realmode_code(void)
  33 {
  34         memcpy((void *)REALMODE_BASE, &asm_realmode_code,
  35                asm_realmode_code_size);
  36
  37         /* Ensure the global pointers are relocated properly. */
  38         realmode_call = PTR_TO_REAL_MODE(asm_realmode_call);
  39         realmode_interrupt = PTR_TO_REAL_MODE(__realmode_interrupt);
  40
  41         debug("Real mode stub @%x: %d bytes\n", REALMODE_BASE,
  42               asm_realmode_code_size);
  43 }
  44
  45 static void setup_rombios(void)
  46 {
  47         const char date[] = "06/11/99";
  48         memcpy((void *)0xffff5, &date, 8);
  49
  50         const char ident[] = "PCI_ISA";
  51         memcpy((void *)0xfffd9, &ident, 7);
  52
  53         /* system model: IBM-AT */
  54         writeb(0xfc, 0xffffe);
  55 }
  56
  57 static int int_exception_handler(void)
  58 {
  59         /* compatibility shim */
  60         struct eregs reg_info = {
  61                 .eax = M.x86.R_EAX,
  62                 .ecx = M.x86.R_ECX,
  63                 .edx = M.x86.R_EDX,
  64                 .ebx = M.x86.R_EBX,
  65                 .esp = M.x86.R_ESP,
  66                 .ebp = M.x86.R_EBP,
  67                 .esi = M.x86.R_ESI,
  68                 .edi = M.x86.R_EDI,
  69                 .vector = M.x86.intno,
  70                 .error_code = 0,
  71                 .eip = M.x86.R_EIP,
  72                 .cs = M.x86.R_CS,
  73                 .eflags = M.x86.R_EFLG
  74         };
  75         struct eregs *regs = &reg_info;
  76
  77         debug("Oops, exception %d while executing option rom\n", regs->vector);
  78         cpu_hlt();
  79
  80         return 0;
  81 }
  82
  83 static int int_unknown_handler(void)
  84 {
  85         debug("Unsupported software interrupt #0x%x eax 0x%x\n",
  86               M.x86.intno, M.x86.R_EAX);
  87
  88         return -1;
  89 }
  90
  91 /* setup interrupt handlers for mainboard */
  92 void bios_set_interrupt_handler(int intnum, int (*int_func)(void))
  93 {
  94         int_handler[intnum] = int_func;
  95 }
  96
  97 static void setup_interrupt_handlers(void)
  98 {
  99         int i;
 100
 101         /*
 102          * The first 16 int_handler functions are not BIOS services,
 103          * but the CPU-generated exceptions ("hardware interrupts")
 104          */
 105         for (i = 0; i < 0x10; i++)
 106                 int_handler[i] = &int_exception_handler;
 107
 108         /* Mark all other int_handler calls as unknown first */
 109         for (i = 0x10; i < 0x100; i++) {
 110                 /* Skip if bios_set_interrupt_handler() isn't called first */
 111                 if (int_handler[i])
 112                         continue;
 113
 114                  /*
 115                   * Now set the default functions that are actually needed
 116                   * to initialize the option roms. The board may override
 117                   * these with bios_set_interrupt_handler()
 118                  */
 119                 switch (i) {
 120                 case 0x10:
 121                         int_handler[0x10] = &int10_handler;
 122                         break;
 123                 case 0x12:
 124                         int_handler[0x12] = &int12_handler;
 125                         break;
 126                 case 0x16:
 127                         int_handler[0x16] = &int16_handler;
 128                         break;
 129                 case 0x1a:
 130                         int_handler[0x1a] = &int1a_handler;
 131                         break;
 132                 default:
 133                         int_handler[i] = &int_unknown_handler;
 134                         break;
 135                 }
 136         }
 137 }
 138
 139 static void write_idt_stub(void *target, u8 intnum)
 140 {
 141         unsigned char *codeptr;
 142
 143         codeptr = (unsigned char *)target;
 144         memcpy(codeptr, &__idt_handler, __idt_handler_size);
 145         codeptr[3] = intnum; /* modify int# in the code stub. */
 146 }
 147
 148 static void setup_realmode_idt(void)
 149 {
 150         struct realmode_idt *idts = NULL;
 151         int i;
 152
 153         /*
 154          * Copy IDT stub code for each interrupt. This might seem wasteful
 155          * but it is really simple
 156          */
 157          for (i = 0; i < 256; i++) {
 158                 idts[i].cs = 0;
 159                 idts[i].offset = 0x1000 + (i * __idt_handler_size);
 160                 write_idt_stub((void *)((ulong)idts[i].offset), i);
 161         }
 162
 163         /*
 164          * Many option ROMs use the hard coded interrupt entry points in the
 165          * system bios. So install them at the known locations.
 166          */
 167
 168         /* int42 is the relocated int10 */
 169         write_idt_stub((void *)0xff065, 0x42);
 170         /* BIOS Int 11 Handler F000:F84D */
 171         write_idt_stub((void *)0xff84d, 0x11);
 172         /* BIOS Int 12 Handler F000:F841 */
 173         write_idt_stub((void *)0xff841, 0x12);
 174         /* BIOS Int 13 Handler F000:EC59 */
 175         write_idt_stub((void *)0xfec59, 0x13);
 176         /* BIOS Int 14 Handler F000:E739 */
 177         write_idt_stub((void *)0xfe739, 0x14);
 178         /* BIOS Int 15 Handler F000:F859 */
 179         write_idt_stub((void *)0xff859, 0x15);
 180         /* BIOS Int 16 Handler F000:E82E */
 181         write_idt_stub((void *)0xfe82e, 0x16);
 182         /* BIOS Int 17 Handler F000:EFD2 */
 183         write_idt_stub((void *)0xfefd2, 0x17);
 184         /* ROM BIOS Int 1A Handler F000:FE6E */
 185         write_idt_stub((void *)0xffe6e, 0x1a);
 186 }
 187
 188 static u8 vbe_get_mode_info(struct vbe_mode_info *mi)
 189 {
 190         u16 buffer_seg;
 191         u16 buffer_adr;
 192         char *buffer;
 193
 194         debug("VBE: Getting information about VESA mode %04x\n",
 195               mi->video_mode);
 196         buffer = PTR_TO_REAL_MODE(asm_realmode_buffer);
 197         buffer_seg = (((unsigned long)buffer) >> 4) & 0xff00;
 198         buffer_adr = ((unsigned long)buffer) & 0xffff;
 199
 200         realmode_interrupt(0x10, VESA_GET_MODE_INFO, 0x0000, mi->video_mode,
 201                            0x0000, buffer_seg, buffer_adr);
 202         memcpy(mi->mode_info_block, buffer, sizeof(struct vbe_mode_info));
 203         mi->valid = true;
 204
 205         return 0;
 206 }
 207
 208 static u8 vbe_set_mode(struct vbe_mode_info *mi)
 209 {
 210         int video_mode = mi->video_mode;
 211
 212         debug("VBE: Setting VESA mode %#04x\n", video_mode);
 213         /* request linear framebuffer mode */
 214         video_mode |= (1 << 14);
 215         /* don't clear the framebuffer, we do that later */
 216         video_mode |= (1 << 15);
 217         realmode_interrupt(0x10, VESA_SET_MODE, video_mode,
 218                            0x0000, 0x0000, 0x0000, 0x0000);
 219
 220         return 0;
 221 }
 222
 223 static void vbe_set_graphics(int vesa_mode, struct vbe_mode_info *mode_info)
 224 {
 225         unsigned char *framebuffer;
 226
 227         mode_info->video_mode = (1 << 14) | vesa_mode;
 228         vbe_get_mode_info(mode_info);
 229
 230         framebuffer = (unsigned char *)(ulong)mode_info->vesa.phys_base_ptr;
 231         debug("VBE: resolution:  %dx%d@%d\n",
 232               le16_to_cpu(mode_info->vesa.x_resolution),
 233               le16_to_cpu(mode_info->vesa.y_resolution),
 234               mode_info->vesa.bits_per_pixel);
 235         debug("VBE: framebuffer: %p\n", framebuffer);
 236         if (!framebuffer) {
 237                 debug("VBE: Mode does not support linear framebuffer\n");
 238                 return;
 239         }
 240
 241         mode_info->video_mode &= 0x3ff;
 242         vbe_set_mode(mode_info);
 243 }
 244
 245 void bios_run_on_x86(struct udevice *dev, unsigned long addr, int vesa_mode,
 246                      struct vbe_mode_info *mode_info)
 247 {
 248         pci_dev_t pcidev = dm_pci_get_bdf(dev);
 249         u32 num_dev;
 250
 251         num_dev = PCI_BUS(pcidev) << 8 | PCI_DEV(pcidev) << 3 |
 252                         PCI_FUNC(pcidev);
 253
 254         /* Needed to avoid exceptions in some ROMs */
 255         interrupt_init();
 256
 257         /* Set up some legacy information in the F segment */
 258         setup_rombios();
 259
 260         /* Set up C interrupt handlers */
 261         setup_interrupt_handlers();
 262
 263         /* Set up real-mode IDT */
 264         setup_realmode_idt();
 265
 266         /* Make sure the code is placed. */
 267         setup_realmode_code();
 268
 269         debug("Calling Option ROM at %lx, pci device %#x...", addr, num_dev);
 270
 271         /* Option ROM entry point is at OPROM start + 3 */
 272         realmode_call(addr + 0x0003, num_dev, 0xffff, 0x0000, 0xffff, 0x0,
 273                       0x0);
 274         debug("done\n");
 275
 276         if (vesa_mode != -1)
 277                 vbe_set_graphics(vesa_mode, mode_info);
 278 }
 279
 280 asmlinkage int interrupt_handler(u32 intnumber, u32 gsfs, u32 dses,
 281                                  u32 edi, u32 esi, u32 ebp, u32 esp,
 282                                  u32 ebx, u32 edx, u32 ecx, u32 eax,
 283                                  u32 cs_ip, u16 stackflags)
 284 {
 285         u32 ip;
 286         u32 cs;
 287         u32 flags;
 288         int ret = 0;
 289
 290         ip = cs_ip & 0xffff;
 291         cs = cs_ip >> 16;
 292         flags = stackflags;
 293
 294 #ifdef CONFIG_REALMODE_DEBUG
 295         debug("oprom: INT# 0x%x\n", intnumber);
 296         debug("oprom: eax: %08x ebx: %08x ecx: %08x edx: %08x\n",
 297               eax, ebx, ecx, edx);
 298         debug("oprom: ebp: %08x esp: %08x edi: %08x esi: %08x\n",
 299               ebp, esp, edi, esi);
 300         debug("oprom:  ip: %04x      cs: %04x   flags: %08x\n",
 301               ip, cs, flags);
 302         debug("oprom: stackflags = %04x\n", stackflags);
 303 #endif
 304
 305         /*
 306          * Fetch arguments from the stack and put them to a place
 307          * suitable for the interrupt handlers
 308          */
 309         M.x86.R_EAX = eax;
 310         M.x86.R_ECX = ecx;
 311         M.x86.R_EDX = edx;
 312         M.x86.R_EBX = ebx;
 313         M.x86.R_ESP = esp;
 314         M.x86.R_EBP = ebp;
 315         M.x86.R_ESI = esi;
 316         M.x86.R_EDI = edi;
 317         M.x86.intno = intnumber;
 318         M.x86.R_EIP = ip;
 319         M.x86.R_CS = cs;
 320         M.x86.R_EFLG = flags;
 321
 322         /* Call the interrupt handler for this interrupt number */
 323         ret = int_handler[intnumber]();
 324
 325         /*
 326          * This code is quite strange...
 327          *
 328          * Put registers back on the stack. The assembler code will pop them
 329          * later. We force (volatile!) changing the values of the parameters
 330          * of this function. We know that they stay alive on the stack after
 331          * we leave this function.
 332          */
 333         *(volatile u32 *)&eax = M.x86.R_EAX;
 334         *(volatile u32 *)&ecx = M.x86.R_ECX;
 335         *(volatile u32 *)&edx = M.x86.R_EDX;
 336         *(volatile u32 *)&ebx = M.x86.R_EBX;
 337         *(volatile u32 *)&esi = M.x86.R_ESI;
 338         *(volatile u32 *)&edi = M.x86.R_EDI;
 339         flags = M.x86.R_EFLG;
 340
 341         /* Pass success or error back to our caller via the CARRY flag */
 342         if (ret) {
 343                 flags &= ~1; /* no error: clear carry */
 344         } else {
 345                 debug("int%02x call returned error\n", intnumber);
 346                 flags |= 1;  /* error: set carry */
 347         }
 348         *(volatile u16 *)&stackflags = flags;
 349
 350         return ret;
 351 }