arch/m68k-amiga/boot/start.c

   1 /*
   2     Copyright © 1995-2010, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: m68k-amiga bootstrap to exec.
   6     Lang: english
   7  */
   8
   9 #include <aros/kernel.h>
  10 #include <exec/resident.h>
  11 #include <exec/execbase.h>
  12 #include <exec/memory.h>
  13 #include <proto/exec.h>
  14
  15 #include "exec_intern.h"
  16 #include "kernel_romtags.h"
  17
  18 #include "amiga_hwreg.h"
  19 #include "amiga_irq.h"
  20
  21 extern const struct Resident Exec_resident;
  22
  23 extern void __clear_bss(const struct KernelBSS *bss);
  24
  25 #define RGB(r,g,b)      ((((r) & 0xf) << 8) | (((g) & 0xf) << 4) | (((b) & 0xf) << 0))
  26
  27 #define CODE_ROM_CHECK  RGB( 4,  4, 4)
  28 #define CODE_RAM_CHECK  RGB( 9,  9, 9)
  29 #define CODE_EXEC_CHECK RGB( 9,  0, 9)
  30 #define CODE_TRAP_FAIL  RGB(12, 12, 0)
  31
  32 static void Exec_ScreenCode(UWORD code)
  33 {
  34         reg_w(BPLCON0, 0x0200);
  35         reg_w(BPL1DAT, 0x0000);
  36         reg_w(COLOR00, code);
  37 }
  38
  39 void DebugInit()
  40 {
  41         /* Set the debug UART to 9600 */
  42         reg_w(SERPER, SERPER_BAUD(SERPER_BASE_PAL, 9600));
  43 }
  44
  45 int DebugPutChar(register int chr)
  46 {
  47         while ((reg_r(SERDATR) & SERDATR_TBE) == 0);
  48
  49         /* Output a char to the debug UART */
  50         reg_w(SERDAT, SERDAT_STP8 | SERDAT_DB8(chr));
  51
  52         return 1;
  53 }
  54
  55 int DebugGetChar(void)
  56 {
  57         while ((reg_r(SERDATR) & SERDATR_RBF) == 0);
  58
  59         return SERDATR_DB8_of(reg_r(SERDATR));
  60 }
  61
  62 #ifdef USE_GDBSTUB
  63 #define mc68020
  64 #include "m68k-gdbstub.c"
  65 #endif
  66
  67 static __attribute__((interrupt)) void Exec_FatalException(void)
  68 {
  69         volatile int i;
  70
  71         Exec_ScreenCode(CODE_TRAP_FAIL);
  72
  73         /* FIXME: Idle loop delay
  74          * We should really wait for a number of
  75          * verical retrace intervals
  76          */
  77         for (i = 0; i < 150000; i++);
  78
  79         /* Reset everything but the CPU, then restart
  80          * at the ROM exception vector
  81          */
  82         asm("reset\n"
  83             "move.l #4,%a0\n"
  84             "jmp    (%a0)\n");
  85 }
  86
  87 static void DebugPuts(register const char *buff)
  88 {
  89         for (; *buff != 0; buff++)
  90                 DebugPutChar(*buff);
  91 }
  92
  93 extern void *_ram_start;
  94 #define MEM_START       ((ULONG)(&_ram_start))
  95 #define MEM_SIZE        (0x00200000-MEM_START)
  96
  97 void DebugPutHex(const char *what, ULONG val)
  98 {
  99         int i;
 100         DebugPuts(what);
 101         DebugPuts(": ");
 102         for (i = 0; i < 8; i ++) {
 103                 DebugPutChar("0123456789abcdef"[(val >> (28 - (i * 4))) & 0xf]);
 104         }
 105         DebugPutChar('\n');
 106 }
 107
 108 extern void __attribute__((interrupt)) Exec_Supervisor_Trap (void);
 109
 110 void __attribute__((interrupt)) cpu_detect_trap(void);
 111 asm (
 112         "       .text\n"
 113         "       .globl cpu_detect_trap\n"
 114         "cpu_detect_trap:\n"
 115         "       addq.l  #2,%sp@(2)\n"
 116         "       move.w  %sr,%d0\n"
 117         "       rte\n"
 118 );
 119
 120 /* Detect 68000 vs 68010/68020 */
 121 ULONG cpu_detect(void)
 122 {
 123         volatile APTR *trap = (NULL + 8);
 124         APTR old_trap6;
 125         UWORD ret;
 126
 127         old_trap6 = trap[6];
 128         trap[6] = cpu_detect_trap;
 129         asm volatile (
 130                 "move.w %%sr,%%d0\n"
 131                 "move.w %%d0,%0\n"
 132                 : "=m" (ret) : : "%d0" );
 133         trap[6] = old_trap6;
 134
 135         if (ret & 0x2000)
 136                 return AFF_68010;
 137         else
 138                 return 0;
 139 }
 140
 141 #if (AROS_FLAVOUR & AROS_FLAVOUR_BINCOMPAT)
 142 /*
 143  * Create a call stub like so:
 144  * foo:
 145  *   movem.l %d0-%d1/%a0-%a1,%sp@-
 146  *     0x48e7 0xc0c0
 147  *   jsr AROS_SLIB_ENTRY(funcname, libname)
 148  *     0x4eb9 .... ....
 149  *   movem.l %sp@+,%d0-%d1/%d0-%a1
 150  *     0x4cdf 0x0303
 151  *   rts
 152  *     0x4e75
 153  */
 154 #define PRESERVE_ALL(lib, libname, funcname, funcid) \
 155         do { \
 156                 UWORD *asmcall; \
 157                 IPTR func = (IPTR)__AROS_GETVECADDR(lib, funcid); \
 158                 asmcall = AllocMem(8 * sizeof(UWORD), MEMF_PUBLIC); \
 159                 /* NOTE: 'asmcall' will intentionally never be freed */ \
 160                 asmcall[0] = 0x48e7; \
 161                 asmcall[1] = 0xc0c0; \
 162                 asmcall[2] = 0x4eb9; \
 163                 asmcall[3] = (func >> 16) & 0xffff; \
 164                 asmcall[4] = (func >>  0) & 0xffff; \
 165                 asmcall[5] = 0x4cdf; \
 166                 asmcall[6] = 0x0303; \
 167                 asmcall[7] = 0x4e75; \
 168                 /* Insert into the library's jumptable */ \
 169                 __AROS_SETVECADDR(lib, funcid, asmcall); \
 170         } while (0)
 171 #else
 172 /* Not needed on EABI */
 173 #define PRESERVE_ALL(lib, libname, funcname, funcid) do { } while (0)
 174 #endif
 175
 176 void start(void)
 177 {
 178         extern void *_bss;
 179         extern void *_bss_end;
 180         extern void *_ss_stack_upper;
 181         extern void *_ss_stack_lower;
 182         APTR *tmp;
 183         int i;
 184         UWORD *kickrom[] = {
 185                 (UWORD *)0x00f80000,
 186                 (UWORD *)0x01000000,
 187                 (UWORD *)0x00f00000,
 188                 (UWORD *)0x00f80000,
 189                 (UWORD *)0x00e00000,
 190                 (UWORD *)0x00e80000,
 191                 (UWORD *)~0,
 192                 (UWORD *)~0,
 193         };
 194         const struct KernelBSS kbss[2] = {
 195                 {
 196                         .addr = &_bss,
 197                         .len = &_bss_end - &_bss,
 198                 }, {
 199                         .addr = 0,
 200                         .len = 0,
 201                 }
 202         };
 203
 204         struct ExecBase *sysBase;
 205         struct MemChunk *mc;
 206         struct MemHeader ChipRAM;
 207         struct MemHeader *mh = &ChipRAM;
 208
 209         *((APTR *)(NULL + 0x4)) = NULL;
 210
 211         /* Let the world know we exist
 212          */
 213         DebugInit();
 214         DebugPuts("[reset]\n");
 215
 216         /* Fill exception table with a stub that will
 217          * reset the ROM
 218          */
 219         tmp = (APTR *)(NULL + 0x8);
 220         for (i = 0; i < 46; i++)
 221                 tmp[i] = Exec_FatalException;
 222
 223         /* Clear the BSS */
 224         __clear_bss(&kbss[0]);
 225         DebugPuts("[bss clear]\n");
 226
 227 #ifdef USE_GDBSTUB
 228         /* Must be after the BSS clear! */
 229         gdbstub();
 230 #endif
 231
 232         /* Set privilige violation trap - we
 233          * need this to support the Exec/Supervisor call
 234          */
 235         tmp[6] = Exec_Supervisor_Trap;
 236
 237         Exec_ScreenCode(CODE_RAM_CHECK);
 238
 239         DebugPuts("[prep SysBase]\n");
 240         Exec_ScreenCode(CODE_EXEC_CHECK);
 241         mc = (struct MemChunk *)(NULL + MEM_START);
 242         mc->mc_Next = NULL;
 243         mc->mc_Bytes = MEM_SIZE;
 244
 245         mh->mh_Node.ln_Succ    = NULL;
 246         mh->mh_Node.ln_Pred    = NULL;
 247         mh->mh_Node.ln_Type    = NT_MEMORY;
 248         mh->mh_Node.ln_Name    = "chip memory";
 249         mh->mh_Node.ln_Pri     = -5;
 250         mh->mh_Attributes      = MEMF_CHIP | MEMF_PUBLIC | MEMF_LOCAL | MEMF_24BITDMA | MEMF_KICK;
 251         mh->mh_First           = mc;
 252         mh->mh_Lower           = (APTR)mc;
 253         mh->mh_Upper           = ((APTR)mc) + mc->mc_Bytes;
 254         mh->mh_Free            = mc->mc_Bytes;
 255         sysBase = PrepareExecBase(mh, NULL, NULL);
 256         DebugPutHex("PrepareExecBase [ret]",(ULONG)sysBase);
 257         *((APTR *)(NULL + 0x4)) = sysBase;
 258         DebugPuts("[init SysBase]\n");
 259
 260         /* Fix up functions that need 'preserves all registers'
 261          * semantics. This AllocMem()s a little wrapper routine
 262          * that pushes the %d0-%d1/%a0-%a1 registers before
 263          * calling the routine.
 264          */
 265 #ifdef THESE_ARE_KNOWN_SAFE_ASM_ROUTINES
 266         PERSERVE_ALL(SysBase, Exec, Disable, 20);
 267         PERSERVE_ALL(SysBase, Exec, Enable, 21);
 268         PRESERVE_ALL(SysBase, Exec, Forbid, 22);
 269 #endif
 270         PRESERVE_ALL(SysBase, Exec, Permit, 23);
 271         PRESERVE_ALL(SysBase, Exec, ObtainSemaphore, 94);
 272         PRESERVE_ALL(SysBase, Exec, ReleaseSemaphore, 95);
 273         PRESERVE_ALL(SysBase, Exec, ObtainSemaphoreShared, 113);
 274
 275
 276         sysBase->SysStkUpper    = (APTR)(&_ss_stack_upper)-1;
 277         sysBase->SysStkLower    = (APTR)&_ss_stack_lower;
 278
 279         /* Determine CPU model */
 280         sysBase->AttnFlags |= cpu_detect();
 281
 282         /* Initialize IRQ subsystem */
 283         AmigaIRQInit(sysBase);
 284
 285         /* Scan for all other ROM Tags */
 286         sysBase->ResModules = krnRomTagScanner(sysBase, kickrom);
 287         DebugPuts("[start] InitCode(RTF_SINGLETASK, 0)\n");
 288         InitCode(RTF_SINGLETASK, 0);
 289
 290         /* We shouldn't get here */
 291         DebugPuts("[DOS Task failed to start]\n");
 292         for (;;)
 293                 breakpoint();
 294 }