arch/arm/boot/compressed/hw-bse.c

   1 /*
   2  * Bright Star Engineering Inc.
   3  *
   4  * code for readng parameters from the
   5  * parameter blocks of the boot block
   6  * flash memory
   7  *
   8  */
   9
  10 static int strcmp(const char *s1, const char *s2)
  11 {
  12   while (*s1 != '\0' && *s1 == *s2)
  13     {
  14       s1++;
  15       s2++;
  16     }
  17
  18   return (*(unsigned char *) s1) - (*(unsigned char *) s2);
  19 }
  20
  21 struct pblk_t {
  22   char type;
  23   unsigned short size;
  24 };
  25
  26 static char *bse_getflashparam(char *name) {
  27   unsigned int esize;
  28   char *q,*r;
  29   unsigned char *p,*e;
  30   struct pblk_t *thepb = (struct pblk_t *) 0x00004000;
  31   struct pblk_t *altpb = (struct pblk_t *) 0x00006000;
  32   if (thepb->type&1) {
  33     if (altpb->type&1) {
  34       /* no valid param block */
  35       return (char*)0;
  36     } else {
  37       /* altpb is valid */
  38       struct pblk_t *tmp;
  39       tmp = thepb;
  40       thepb = altpb;
  41       altpb = tmp;
  42     }
  43   }
  44   p = (char*)thepb + sizeof(struct pblk_t);
  45   e = p + thepb->size;
  46   while (p < e) {
  47     q = p;
  48     esize = *p;
  49     if (esize == 0xFF) break;
  50     if (esize == 0) break;
  51     if (esize > 127) {
  52       esize = (esize&0x7F)<<8 | p[1];
  53       q++;
  54     }
  55     q++;
  56     r=q;
  57     if (*r && ((name == 0) || (!strcmp(name,r)))) {
  58       while (*q++) ;
  59       return q;
  60     }
  61     p+=esize;
  62   }
  63   return (char*)0;
  64 }
  65
  66 void bse_setup(void) {
  67   /* extract the linux cmdline from flash */
  68   char *name=bse_getflashparam("linuxboot");
  69   char *x = (char *)0xc0000100;
  70   if (name) {
  71     while (*name) *x++=*name++;
  72   }
  73   *x=0;
  74 }