arch/powerpc/boot/mktree.c

   1 /*
   2  * Makes a tree bootable image for IBM Evaluation boards.
   3  * Basically, just take a zImage, skip the ELF header, and stuff
   4  * a 32 byte header on the front.
   5  *
   6  * We use htonl, which is a network macro, to make sure we're doing
   7  * The Right Thing on an LE machine.  It's non-obvious, but it should
   8  * work on anything BSD'ish.
   9  */
  10
  11 #include <fcntl.h>
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <sys/stat.h>
  16 #include <unistd.h>
  17 #include <netinet/in.h>
  18 #ifdef __sun__
  19 #include <inttypes.h>
  20 #else
  21 #include <stdint.h>
  22 #endif
  23
  24 /* This gets tacked on the front of the image.  There are also a few
  25  * bytes allocated after the _start label used by the boot rom (see
  26  * head.S for details).
  27  */
  28 typedef struct boot_block {
  29         uint32_t bb_magic;              /* 0x0052504F */
  30         uint32_t bb_dest;               /* Target address of the image */
  31         uint32_t bb_num_512blocks;      /* Size, rounded-up, in 512 byte blks */
  32         uint32_t bb_debug_flag; /* Run debugger or image after load */
  33         uint32_t bb_entry_point;        /* The image address to start */
  34         uint32_t bb_checksum;   /* 32 bit checksum including header */
  35         uint32_t reserved[2];
  36 } boot_block_t;
  37
  38 #define IMGBLK  512
  39 char    tmpbuf[IMGBLK];
  40
  41 int main(int argc, char *argv[])
  42 {
  43         int     in_fd, out_fd;
  44         int     nblks, i;
  45         uint    cksum, *cp;
  46         struct  stat    st;
  47         boot_block_t    bt;
  48
  49         if (argc < 5) {
  50                 fprintf(stderr, "usage: %s <zImage-file> <boot-image> <load address> <entry point>\n",argv[0]);
  51                 exit(1);
  52         }
  53
  54         if (stat(argv[1], &st) < 0) {
  55                 perror("stat");
  56                 exit(2);
  57         }
  58
  59         nblks = (st.st_size + IMGBLK) / IMGBLK;
  60
  61         bt.bb_magic = htonl(0x0052504F);
  62
  63         /* If we have the optional entry point parameter, use it */
  64         bt.bb_dest = htonl(strtoul(argv[3], NULL, 0));
  65         bt.bb_entry_point = htonl(strtoul(argv[4], NULL, 0));
  66
  67         /* We know these from the linker command.
  68          * ...and then move it up into memory a little more so the
  69          * relocation can happen.
  70          */
  71         bt.bb_num_512blocks = htonl(nblks);
  72         bt.bb_debug_flag = 0;
  73
  74         bt.bb_checksum = 0;
  75
  76         /* To be neat and tidy :-).
  77         */
  78         bt.reserved[0] = 0;
  79         bt.reserved[1] = 0;
  80
  81         if ((in_fd = open(argv[1], O_RDONLY)) < 0) {
  82                 perror("zImage open");
  83                 exit(3);
  84         }
  85
  86         if ((out_fd = open(argv[2], (O_RDWR | O_CREAT | O_TRUNC), 0666)) < 0) {
  87                 perror("bootfile open");
  88                 exit(3);
  89         }
  90
  91         cksum = 0;
  92         cp = (void *)&bt;
  93         for (i=0; i<sizeof(bt)/sizeof(uint); i++)
  94                 cksum += *cp++;
  95
  96         /* Assume zImage is an ELF file, and skip the 64K header.
  97         */
  98         if (read(in_fd, tmpbuf, IMGBLK) != IMGBLK) {
  99                 fprintf(stderr, "%s is too small to be an ELF image\n",
 100                                 argv[1]);
 101                 exit(4);
 102         }
 103
 104         if ((*(uint *)tmpbuf) != htonl(0x7f454c46)) {
 105                 fprintf(stderr, "%s is not an ELF image\n", argv[1]);
 106                 exit(4);
 107         }
 108
 109         if (lseek(in_fd, (64 * 1024), SEEK_SET) < 0) {
 110                 fprintf(stderr, "%s failed to seek in ELF image\n", argv[1]);
 111                 exit(4);
 112         }
 113
 114         nblks -= (64 * 1024) / IMGBLK;
 115
 116         /* And away we go......
 117         */
 118         if (write(out_fd, &bt, sizeof(bt)) != sizeof(bt)) {
 119                 perror("boot-image write");
 120                 exit(5);
 121         }
 122
 123         while (nblks-- > 0) {
 124                 if (read(in_fd, tmpbuf, IMGBLK) < 0) {
 125                         perror("zImage read");
 126                         exit(5);
 127                 }
 128                 cp = (uint *)tmpbuf;
 129                 for (i=0; i<sizeof(tmpbuf)/sizeof(uint); i++)
 130                         cksum += *cp++;
 131                 if (write(out_fd, tmpbuf, sizeof(tmpbuf)) != sizeof(tmpbuf)) {
 132                         perror("boot-image write");
 133                         exit(5);
 134                 }
 135         }
 136
 137         /* rewrite the header with the computed checksum.
 138         */
 139         bt.bb_checksum = htonl(cksum);
 140         if (lseek(out_fd, 0, SEEK_SET) < 0) {
 141                 perror("rewrite seek");
 142                 exit(1);
 143         }
 144         if (write(out_fd, &bt, sizeof(bt)) != sizeof(bt)) {
 145                 perror("boot-image rewrite");
 146                 exit(1);
 147         }
 148
 149         exit(0);
 150 }