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
  14 #include "exec_intern.h"
  15 #include "kernel_romtags.h"
  16
  17 #define USE_GDBSTUB
  18
  19 extern const struct Resident Exec_resident;
  20
  21 extern void __clear_bss(const struct KernelBSS *bss);
  22
  23 /** Screen/Serial Debug **/
  24
  25 #define SERPER_BASE_PAL         3546895
  26 #define SERPER_BASE_NTSC        3579545
  27 #define SERPER                  0x32
  28 #define   SERPER_BAUD(base, x)  (((base)/(x)-1) & 0x7fff)       /* Baud rate */
  29 #define SERDATR                 0x18
  30 #define   SERDATR_OVRUN         (1 << 15)       /* Overrun */
  31 #define   SERDATR_RBF           (1 << 14)       /* Rx Buffer Full */
  32 #define   SERDATR_TBE           (1 << 13)       /* Tx Buffer Empty */
  33 #define   SERDATR_TSRE          (1 << 12)       /* Tx Shift Empty */
  34 #define   SERDATR_RXD           (1 << 11)       /* Rx Pin */
  35 #define   SERDATR_STP9          (1 <<  9)       /* Stop bit (if 9 data) */
  36 #define   SERDATR_STP8          (1 <<  8)       /* Stop bit (if 8 data) */
  37 #define   SERDATR_DB9_of(x)     ((x) & 0x1ff)   /* 9-bit data */
  38 #define   SERDATR_DB8_of(x)     ((x) & 0xff)    /* 8-bit data */
  39 #define ADKCON                  0x9e
  40 #define   ADKCON_SETCLR         (1 << 15)
  41 #define   ADKCON_UARTBRK        (1 << 11)       /* Force break */
  42 #define SERDAT                  0x30
  43 #define   SERDAT_STP9           (1 << 9)
  44 #define   SERDAT_STP8           (1 << 8)
  45 #define   SERDAT_DB9(x)         ((x) & 0x1ff)
  46 #define   SERDAT_DB8(x)         ((x) & 0xff)
  47
  48 #define BPLCON0                 0x100
  49 #define BPL1DAT                 0x110
  50 #define COLOR00                 0x180
  51
  52 static inline void reg_w(ULONG reg, UWORD val)
  53 {
  54         volatile UWORD *r = (void *)(0xdff000 + reg);
  55
  56         *r = val;
  57 }
  58
  59 static inline UWORD reg_r(ULONG reg)
  60 {
  61         volatile UWORD *r = (void *)(0xdff000 + reg);
  62
  63         return *r;
  64 }
  65
  66 #define RGB(r,g,b)      ((((r) & 0xf) << 8) | (((g) & 0xf) << 4) | (((b) & 0xf) << 0))
  67
  68 #define CODE_ROM_CHECK  RGB( 4,  4, 4)
  69 #define CODE_RAM_CHECK  RGB( 9,  9, 9)
  70 #define CODE_EXEC_CHECK RGB( 9,  0, 9)
  71 #define CODE_TRAP_FAIL  RGB(12, 12, 0)
  72
  73 static void Exec_ScreenCode(UWORD code)
  74 {
  75         reg_w(BPLCON0, 0x0200);
  76         reg_w(BPL1DAT, 0x0000);
  77         reg_w(COLOR00, code);
  78 }
  79
  80 void DebugInit()
  81 {
  82         /* Set the debug UART to 9600 */
  83         reg_w(SERPER, SERPER_BAUD(SERPER_BASE_PAL, 9600));
  84 }
  85
  86 int DebugPutChar(register int chr)
  87 {
  88         while ((reg_r(SERDATR) & SERDATR_TBE) == 0);
  89
  90         /* Output a char to the debug UART */
  91         reg_w(SERDAT, SERDAT_STP8 | SERDAT_DB8(chr));
  92
  93         return 1;
  94 }
  95
  96 int DebugGetChar(void)
  97 {
  98         while ((reg_r(SERDATR) & SERDATR_RBF) == 0);
  99
 100         return SERDATR_DB8_of(reg_r(SERDATR));
 101 }
 102
 103 #ifdef USE_GDBSTUB
 104 #define mc68020
 105 #include "m68k-gdbstub.c"
 106 #endif
 107
 108 static __attribute__((interrupt)) void Exec_FatalException(void)
 109 {
 110         volatile int i;
 111
 112         Exec_ScreenCode(CODE_TRAP_FAIL);
 113
 114         /* FIXME: Idle loop delay
 115          * We should really wait for a number of
 116          * verical retrace intervals
 117          */
 118         for (i = 0; i < 150000; i++);
 119
 120         /* Reset everything but the CPU, then restart
 121          * at the ROM exception vector
 122          */
 123         asm("reset\n"
 124             "move.l #4,%a0\n"
 125             "jmp    (%a0)\n");
 126 }
 127
 128 static void DebugPuts(register const char *buff)
 129 {
 130         for (; *buff != 0; buff++)
 131                 DebugPutChar(*buff);
 132 }
 133
 134 #define MEM_START       0x00040000
 135 #define MEM_SIZE        0x001c0000
 136
 137 struct MemHeader ChipRAM;
 138
 139 void DebugPutHex(const char *what, ULONG val)
 140 {
 141         int i;
 142         DebugPuts(what);
 143         DebugPuts(": ");
 144         for (i = 0; i < 8; i ++) {
 145                 DebugPutChar("0123456789abcdef"[(val >> (28 - (i * 4))) & 0xf]);
 146         }
 147         DebugPutChar('\n');
 148 }
 149
 150 void start(void)
 151 {
 152         extern void *_bss;
 153         extern void *_bss_end;
 154         extern void *_stack;
 155         extern void *_stack_end;
 156         APTR *tmp;
 157         int i;
 158         UWORD *kickrom[4] = {
 159                 (UWORD *)0x00f80000,
 160                 (UWORD *)0x01000000,
 161                 (UWORD *)~0,
 162                 (UWORD *)~0,
 163         };
 164         const struct KernelBSS kbss[2] = {
 165                 {
 166                         .addr = &_bss,
 167                         .len = &_bss_end - &_bss,
 168                 }, {
 169                         .addr = 0,
 170                         .len = 0,
 171                 }
 172         };
 173
 174         struct ExecBase *sysBase;
 175         struct MemChunk *mc;
 176         struct MemHeader *mh = &ChipRAM;
 177
 178         *((APTR *)(NULL + 0x4)) = NULL;
 179
 180         /* Set the world know we exist
 181          */
 182         DebugInit();
 183         DebugPuts("[reset]\n");
 184
 185         /* Fill exception table with a stub that will
 186          * reset the ROM
 187          */
 188         tmp = (APTR *)(NULL + 0x8);
 189         for (i = 0; i < 46; i++)
 190                 tmp[i] = Exec_FatalException;
 191
 192         /* Clear the BSS */
 193         __clear_bss(&kbss[0]);
 194         DebugPuts("[bss clear]\n");
 195
 196 #ifdef USE_GDBSTUB
 197         /* Must be after the BSS clear! */
 198         gdbstub();
 199 #endif
 200
 201         Exec_ScreenCode(CODE_RAM_CHECK);
 202
 203         DebugPuts("[prep SysBase]\n");
 204         Exec_ScreenCode(CODE_EXEC_CHECK);
 205         mc = (struct MemChunk *)(NULL + MEM_START);
 206         mc->mc_Next = NULL;
 207         mc->mc_Bytes = MEM_SIZE;
 208
 209         mh->mh_Node.ln_Succ    = NULL;
 210         mh->mh_Node.ln_Pred    = NULL;
 211         mh->mh_Node.ln_Type    = NT_MEMORY;
 212         mh->mh_Node.ln_Name    = "chip memory";
 213         mh->mh_Node.ln_Pri     = -5;
 214         mh->mh_Attributes      = MEMF_CHIP | MEMF_PUBLIC | MEMF_LOCAL | MEMF_24BITDMA | MEMF_KICK;
 215         mh->mh_First           = mc;
 216         mh->mh_Lower           = (APTR)mc;
 217         mh->mh_Upper           = ((APTR)mc) + mc->mc_Bytes;
 218         mh->mh_Free            = mc->mc_Bytes;
 219         sysBase = PrepareExecBase(mh, NULL, NULL);
 220         DebugPutHex("PrepareExecBase [ret]",(ULONG)sysBase);
 221         *((APTR *)(NULL + 0x4)) = sysBase;
 222         DebugPuts("[init SysBase]\n");
 223
 224         sysBase->SysStkUpper    = (APTR)&_stack_end-1;
 225         sysBase->SysStkLower    = (APTR)&_stack;
 226         sysBase->ChkBase=~(ULONG)sysBase;
 227
 228         /* Scan for all other ROM Tags */
 229         sysBase->ResModules = krnRomTagScanner(sysBase, kickrom);
 230         DebugPuts("[start] InitCode(RTF_SINGLETASK, 0)\n");
 231         InitCode(RTF_SINGLETASK, 0);
 232
 233         /* We shouldn't get here */
 234         DebugPuts("[DOS Task failed to start]\n");
 235         for (;;)
 236                 breakpoint();
 237 }