arch/ppc/boot/simple/misc-embedded.c

   1 /*
   2  * Originally adapted by Gary Thomas.  Much additional work by
   3  * Cort Dougan <cort@fsmlabs.com>.  On top of that still more work by
   4  * Dan Malek <dmalek@jlc.net>.
   5  *
   6  * Currently maintained by: Tom Rini <trini@kernel.crashing.org>
   7  */
   8
   9 #include <linux/config.h>
  10 #include <linux/types.h>
  11 #include <linux/string.h>
  12 #include <asm/bootinfo.h>
  13 #include <asm/mmu.h>
  14 #include <asm/page.h>
  15 #include <asm/residual.h>
  16 #if defined(CONFIG_4xx)
  17 #include <asm/ibm4xx.h>
  18 #elif defined(CONFIG_8xx)
  19 #include <asm/mpc8xx.h>
  20 #elif defined(CONFIG_8260)
  21 #include <asm/mpc8260.h>
  22 #endif
  23
  24 #include "nonstdio.h"
  25
  26 /* The linker tells us where the image is. */
  27 extern char __image_begin, __image_end;
  28 extern char __ramdisk_begin, __ramdisk_end;
  29 extern char _end[];
  30
  31 /* Because of the limited amount of memory on embedded, it presents
  32  * loading problems.  The biggest is that we load this boot program
  33  * into a relatively low memory address, and the Linux kernel Bss often
  34  * extends into this space when it get loaded.  When the kernel starts
  35  * and zeros the BSS space, it also writes over the information we
  36  * save here and pass to the kernel (usually board info).
  37  * On these boards, we grab some known memory holes to hold this information.
  38  */
  39 char cmd_buf[256];
  40 char *cmd_line = cmd_buf;
  41 char *avail_ram;
  42 char *end_avail;
  43 char *zimage_start;
  44
  45 /* This is for 4xx treeboot.  It provides a place for the bootrom
  46  * give us a pointer to a rom environment command line.
  47  */
  48 char *bootrom_cmdline = "";
  49
  50 /* This is the default cmdline that will be given to the user at boot time..
  51  * If none was specified at compile time, we'll give it one that should work.
  52  * -- Tom */
  53 #ifdef CONFIG_CMDLINE_BOOL
  54 char compiled_string[] = CONFIG_CMDLINE;
  55 #endif
  56 char ramroot_string[] = "root=/dev/ram";
  57 char netroot_string[] = "root=/dev/nfs rw ip=on";
  58
  59 /* Serial port to use. */
  60 unsigned long com_port;
  61
  62 /* We need to make sure that this is before the images to ensure
  63  * that it's in a mapped location. - Tom */
  64 bd_t hold_resid_buf __attribute__ ((__section__ (".data.boot")));
  65 bd_t *hold_residual = &hold_resid_buf;
  66
  67 extern unsigned long serial_init(int chan, bd_t *bp);
  68 extern void serial_close(unsigned long com_port);
  69 extern unsigned long start;
  70 extern void flush_instruction_cache(void);
  71 extern void gunzip(void *, int, unsigned char *, int *);
  72 extern void embed_config(bd_t **bp);
  73
  74 /* Weak function for boards which don't need to build the
  75  * board info struct because they are using PPCBoot/U-Boot.
  76  */
  77 void __attribute__ ((weak))
  78 embed_config(bd_t **bdp)
  79 {
  80 }
  81
  82 unsigned long
  83 load_kernel(unsigned long load_addr, int num_words, unsigned long cksum, bd_t *bp)
  84 {
  85         char *cp, ch;
  86         int timer = 0, zimage_size;
  87         unsigned long initrd_size;
  88
  89         /* First, capture the embedded board information.  Then
  90          * initialize the serial console port.
  91          */
  92         embed_config(&bp);
  93 #if defined(CONFIG_SERIAL_CPM_CONSOLE) || defined(CONFIG_SERIAL_8250_CONSOLE)
  94         com_port = serial_init(0, bp);
  95 #endif
  96
  97         /* Grab some space for the command line and board info.  Since
  98          * we no longer use the ELF header, but it was loaded, grab
  99          * that space.
 100          */
 101 #ifdef CONFIG_MBX
 102         /* Because of the way the MBX loads the ELF image, we can't
 103          * tell where we started.  We read a magic variable from the NVRAM
 104          * that gives us the intermediate buffer load address.
 105          */
 106         load_addr = *(uint *)0xfa000020;
 107         load_addr += 0x10000;           /* Skip ELF header */
 108 #endif
 109         /* copy board data */
 110         if (bp)
 111                 memcpy(hold_residual,bp,sizeof(bd_t));
 112
 113         /* Set end of memory available to us.  It is always the highest
 114          * memory address provided by the board information.
 115          */
 116         end_avail = (char *)(bp->bi_memsize);
 117
 118         puts("\nloaded at:     "); puthex(load_addr);
 119         puts(" "); puthex((unsigned long)(load_addr + (4*num_words))); puts("\n");
 120         if ( (unsigned long)load_addr != (unsigned long)&start ) {
 121                 puts("relocated to:  "); puthex((unsigned long)&start);
 122                 puts(" ");
 123                 puthex((unsigned long)((unsigned long)&start + (4*num_words)));
 124                 puts("\n");
 125         }
 126
 127         if ( bp ) {
 128                 puts("board data at: "); puthex((unsigned long)bp);
 129                 puts(" ");
 130                 puthex((unsigned long)((unsigned long)bp + sizeof(bd_t)));
 131                 puts("\nrelocated to:  ");
 132                 puthex((unsigned long)hold_residual);
 133                 puts(" ");
 134                 puthex((unsigned long)((unsigned long)hold_residual + sizeof(bd_t)));
 135                 puts("\n");
 136         }
 137
 138         /*
 139          * We link ourself to an arbitrary low address.  When we run, we
 140          * relocate outself to that address.  __image_being points to
 141          * the part of the image where the zImage is. -- Tom
 142          */
 143         zimage_start = (char *)(unsigned long)(&__image_begin);
 144         zimage_size = (unsigned long)(&__image_end) -
 145                         (unsigned long)(&__image_begin);
 146
 147         initrd_size = (unsigned long)(&__ramdisk_end) -
 148                 (unsigned long)(&__ramdisk_begin);
 149
 150         /*
 151          * The zImage and initrd will be between start and _end, so they've
 152          * already been moved once.  We're good to go now. -- Tom
 153          */
 154         puts("zimage at:     "); puthex((unsigned long)zimage_start);
 155         puts(" "); puthex((unsigned long)(zimage_size+zimage_start));
 156         puts("\n");
 157
 158         if ( initrd_size ) {
 159                 puts("initrd at:     ");
 160                 puthex((unsigned long)(&__ramdisk_begin));
 161                 puts(" "); puthex((unsigned long)(&__ramdisk_end));puts("\n");
 162         }
 163
 164         /*
 165          * setup avail_ram - this is the first part of ram usable
 166          * by the uncompress code.  Anything after this program in RAM
 167          * is now fair game. -- Tom
 168          */
 169         avail_ram = (char *)PAGE_ALIGN((unsigned long)_end);
 170
 171         puts("avail ram:     "); puthex((unsigned long)avail_ram); puts(" ");
 172         puthex((unsigned long)end_avail); puts("\n");
 173         puts("\nLinux/PPC load: ");
 174         cp = cmd_line;
 175         /* This is where we try and pick the right command line for booting.
 176          * If we were given one at compile time, use it.  It Is Right.
 177          * If we weren't, see if we have a ramdisk.  If so, thats root.
 178          * When in doubt, give them the netroot (root=/dev/nfs rw) -- Tom
 179          */
 180 #ifdef CONFIG_CMDLINE_BOOL
 181         memcpy (cmd_line, compiled_string, sizeof(compiled_string));
 182 #else
 183         if ( initrd_size )
 184                 memcpy (cmd_line, ramroot_string, sizeof(ramroot_string));
 185         else
 186                 memcpy (cmd_line, netroot_string, sizeof(netroot_string));
 187 #endif
 188         while ( *cp )
 189                 putc(*cp++);
 190         while (timer++ < 5*1000) {
 191                 if (tstc()) {
 192                         while ((ch = getc()) != '\n' && ch != '\r') {
 193                                 if (ch == '\b' || ch == '\177') {
 194                                         if (cp != cmd_line) {
 195                                                 cp--;
 196                                                 puts("\b \b");
 197                                         }
 198                                 } else if (ch == '\030'         /* ^x */
 199                                            || ch == '\025') {   /* ^u */
 200                                         while (cp != cmd_line) {
 201                                                 cp--;
 202                                                 puts("\b \b");
 203                                         }
 204                                 } else {
 205                                         *cp++ = ch;
 206                                         putc(ch);
 207                                 }
 208                         }
 209                         break;  /* Exit 'timer' loop */
 210                 }
 211                 udelay(1000);  /* 1 msec */
 212         }
 213         *cp = 0;
 214         puts("\nUncompressing Linux...");
 215
 216         gunzip(0, 0x400000, zimage_start, &zimage_size);
 217         flush_instruction_cache();
 218         puts("done.\n");
 219         {
 220                 struct bi_record *rec;
 221                 unsigned long initrd_loc = 0;
 222                 unsigned long rec_loc = _ALIGN((unsigned long)(zimage_size) +
 223                                 (1 << 20) - 1, (1 << 20));
 224                 rec = (struct bi_record *)rec_loc;
 225
 226                 /* We need to make sure that the initrd and bi_recs do not
 227                  * overlap. */
 228                 if ( initrd_size ) {
 229                         initrd_loc = (unsigned long)(&__ramdisk_begin);
 230                         /* If the bi_recs are in the middle of the current
 231                          * initrd, move the initrd to the next MB
 232                          * boundary. */
 233                         if ((rec_loc > initrd_loc) &&
 234                                         ((initrd_loc + initrd_size)
 235                                          > rec_loc)) {
 236                                 initrd_loc = _ALIGN((unsigned long)(zimage_size)
 237                                                 + (2 << 20) - 1, (2 << 20));
 238                                 memmove((void *)initrd_loc, &__ramdisk_begin,
 239                                          initrd_size);
 240                                 puts("initrd moved:  "); puthex(initrd_loc);
 241                                 puts(" "); puthex(initrd_loc + initrd_size);
 242                                 puts("\n");
 243                         }
 244                 }
 245
 246                 rec->tag = BI_FIRST;
 247                 rec->size = sizeof(struct bi_record);
 248                 rec = (struct bi_record *)((unsigned long)rec + rec->size);
 249
 250                 rec->tag = BI_CMD_LINE;
 251                 memcpy( (char *)rec->data, cmd_line, strlen(cmd_line)+1);
 252                 rec->size = sizeof(struct bi_record) + strlen(cmd_line) + 1;
 253                 rec = (struct bi_record *)((unsigned long)rec + rec->size);
 254
 255                 if ( initrd_size ) {
 256                         rec->tag = BI_INITRD;
 257                         rec->data[0] = initrd_loc;
 258                         rec->data[1] = initrd_size;
 259                         rec->size = sizeof(struct bi_record) + 2 *
 260                                 sizeof(unsigned long);
 261                         rec = (struct bi_record *)((unsigned long)rec +
 262                                         rec->size);
 263                 }
 264
 265                 rec->tag = BI_LAST;
 266                 rec->size = sizeof(struct bi_record);
 267                 rec = (struct bi_record *)((unsigned long)rec + rec->size);
 268         }
 269         puts("Now booting the kernel\n");
 270 #if defined(CONFIG_SERIAL_CPM_CONSOLE) || defined(CONFIG_SERIAL_8250_CONSOLE)
 271         serial_close(com_port);
 272 #endif
 273
 274         return (unsigned long)hold_residual;
 275 }