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