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