arch/mips/dec/boot/decstation.c

   1 /*
   2  * arch/mips/dec/decstation.c
   3  */
   4 #include <linux/config.h>
   5
   6 #define RELOC
   7 #define INITRD
   8 #define DEBUG_BOOT
   9
  10 /*
  11  * Magic number indicating REX PROM available on DECSTATION.
  12  */
  13 #define REX_PROM_MAGIC          0x30464354
  14
  15 #define REX_PROM_CLEARCACHE     0x7c/4
  16 #define REX_PROM_PRINTF         0x30/4
  17
  18 #define VEC_RESET               0xBFC00000              /* Prom base address */
  19 #define PMAX_PROM_ENTRY(x)      (VEC_RESET+((x)*8))     /* Prom jump table */
  20 #define PMAX_PROM_PRINTF        PMAX_PROM_ENTRY(17)
  21
  22 #define PARAM   (k_start + 0x2000)
  23
  24 #define LOADER_TYPE (*(unsigned char *) (PARAM+0x210))
  25 #define INITRD_START (*(unsigned long *) (PARAM+0x218))
  26 #define INITRD_SIZE (*(unsigned long *) (PARAM+0x21c))
  27
  28 extern int _ftext, _end;                /* begin and end of kernel image */
  29 extern void *__rd_start, *__rd_end;     /* begin and end of ramdisk image */
  30 extern void kernel_entry(int, char **, unsigned long, int *);
  31
  32 void * memcpy(void * dest, const void *src, unsigned int count)
  33 {
  34         unsigned long *tmp = (unsigned long *) dest, *s = (unsigned long *) src;
  35
  36         count >>= 2;
  37         while (count--)
  38                 *tmp++ = *s++;
  39
  40         return dest;
  41 }
  42
  43 void dec_entry(int argc, char **argv,
  44                unsigned long magic, int *prom_vec)
  45 {
  46         void (*rex_clear_cache)(void);
  47         int (*prom_printf)(char *, ...);
  48         unsigned long k_start, len;
  49
  50         /*
  51          * The DS5100 leaves cpu with BEV enabled, clear it.
  52          */
  53         asm(    "lui\t$8,0x3000\n\t"
  54                 "mtc0\t$8,$12\n\t"
  55                 ".section\t.sdata\n\t"
  56                 ".section\t.sbss\n\t"
  57                 ".section\t.text"
  58                 : : : "$8");
  59
  60 #ifdef DEBUG_BOOT
  61         if (magic == REX_PROM_MAGIC) {
  62         prom_printf = (int (*)(char *, ...)) *(prom_vec + REX_PROM_PRINTF);
  63         } else {
  64                 prom_printf = (int (*)(char *, ...)) PMAX_PROM_PRINTF;
  65         }
  66         prom_printf("Launching kernel...\n");
  67 #endif
  68
  69         k_start = (unsigned long) (&kernel_entry) & 0xffff0000;
  70
  71 #ifdef RELOC
  72         /*
  73          * Now copy kernel image to its destination.
  74          */
  75         len = ((unsigned long) (&_end) - k_start);
  76         memcpy((void *)k_start, &_ftext, len);
  77 #endif
  78
  79         if (magic == REX_PROM_MAGIC) {
  80                 rex_clear_cache = (void (*)(void)) * (prom_vec + REX_PROM_CLEARCACHE);
  81                 rex_clear_cache();
  82         }
  83
  84 #ifdef CONFIG_BLK_DEV_INITRD
  85         LOADER_TYPE = 1;
  86         INITRD_START = (long)&__rd_start;
  87         INITRD_SIZE = (long)&__rd_end - (long)&__rd_start;
  88 #endif
  89
  90         kernel_entry(argc, argv, magic, prom_vec);
  91 }