arch/m68k/kernel/uboot.c

   1 /*
   2  * uboot.c -- uboot arguments support
   3  *
   4  * This file is subject to the terms and conditions of the GNU General Public
   5  * License.  See the file COPYING in the main directory of this archive
   6  * for more details.
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/sched.h>
  11 #include <linux/delay.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/fb.h>
  14 #include <linux/module.h>
  15 #include <linux/mm.h>
  16 #include <linux/console.h>
  17 #include <linux/errno.h>
  18 #include <linux/string.h>
  19 #include <linux/memblock.h>
  20 #include <linux/seq_file.h>
  21 #include <linux/init.h>
  22 #include <linux/initrd.h>
  23 #include <linux/root_dev.h>
  24 #include <linux/rtc.h>
  25
  26 #include <asm/setup.h>
  27 #include <asm/irq.h>
  28 #include <asm/machdep.h>
  29 #include <asm/pgtable.h>
  30 #include <asm/sections.h>
  31
  32 /*
  33  * parse_uboot_commandline
  34  *
  35  * Copies u-boot commandline arguments and store them in the proper linux
  36  * variables.
  37  *
  38  * Assumes:
  39  *      _init_sp global contains the address in the stack pointer when the
  40  *      kernel starts (see head.S::_start)
  41  *
  42  *      U-Boot calling convention:
  43  *      (*kernel) (kbd, initrd_start, initrd_end, cmd_start, cmd_end);
  44  *
  45  *      _init_sp can be parsed as such
  46  *
  47  *      _init_sp+00 = u-boot cmd after jsr into kernel (skip)
  48  *      _init_sp+04 = &kernel board_info (residual data)
  49  *      _init_sp+08 = &initrd_start
  50  *      _init_sp+12 = &initrd_end
  51  *      _init_sp+16 = &cmd_start
  52  *      _init_sp+20 = &cmd_end
  53  *
  54  *      This also assumes that the memory locations pointed to are still
  55  *      unmodified. U-boot places them near the end of external SDRAM.
  56  *
  57  * Argument(s):
  58  *      commandp = the linux commandline arg container to fill.
  59  *      size     = the sizeof commandp.
  60  *
  61  * Returns:
  62  */
  63 static void __init parse_uboot_commandline(char *commandp, int size)
  64 {
  65         extern unsigned long _init_sp;
  66         unsigned long *sp;
  67         unsigned long uboot_kbd;
  68         unsigned long uboot_initrd_start, uboot_initrd_end;
  69         unsigned long uboot_cmd_start, uboot_cmd_end;
  70
  71         sp = (unsigned long *)_init_sp;
  72         uboot_kbd = sp[1];
  73         uboot_initrd_start = sp[2];
  74         uboot_initrd_end = sp[3];
  75         uboot_cmd_start = sp[4];
  76         uboot_cmd_end = sp[5];
  77
  78         if (uboot_cmd_start && uboot_cmd_end)
  79                 strncpy(commandp, (const char *)uboot_cmd_start, size);
  80 #if defined(CONFIG_BLK_DEV_INITRD)
  81         if (uboot_initrd_start && uboot_initrd_end &&
  82             (uboot_initrd_end > uboot_initrd_start)) {
  83                 initrd_start = uboot_initrd_start;
  84                 initrd_end = uboot_initrd_end;
  85                 ROOT_DEV = Root_RAM0;
  86                 pr_info("initrd at 0x%lx:0x%lx\n", initrd_start, initrd_end);
  87         }
  88 #endif /* if defined(CONFIG_BLK_DEV_INITRD) */
  89 }
  90
  91 __init void process_uboot_commandline(char *commandp, int size)
  92 {
  93         int len, n;
  94
  95         n = strnlen(commandp, size);
  96         commandp += n;
  97         len = size - n;
  98         if (len) {
  99                 /* Add the whitespace separator */
 100                 *commandp++ = ' ';
 101                 len--;
 102         }
 103
 104         parse_uboot_commandline(commandp, len);
 105         commandp[len - 1] = 0;
 106 }