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/sections.h>
 30#include <asm/bootinfo.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 */
 63static void __init parse_uboot_commandline(char *commandp, int size)
 64{
 65	extern unsigned long _init_sp;
 66	unsigned long *sp;
 67	unsigned long uboot_cmd_start, uboot_cmd_end;
 68#if defined(CONFIG_BLK_DEV_INITRD)
 69	unsigned long uboot_initrd_start, uboot_initrd_end;
 70#endif /* if defined(CONFIG_BLK_DEV_INITRD) */
 71
 72	sp = (unsigned long *)_init_sp;
 73	uboot_cmd_start = sp[4];
 74	uboot_cmd_end = sp[5];
 75
 76	if (uboot_cmd_start && uboot_cmd_end)
 77		strncpy(commandp, (const char *)uboot_cmd_start, size);
 78
 79#if defined(CONFIG_BLK_DEV_INITRD)
 80	uboot_initrd_start = sp[2];
 81	uboot_initrd_end = sp[3];
 82
 83	if (uboot_initrd_start && uboot_initrd_end &&
 84	    (uboot_initrd_end > uboot_initrd_start)) {
 85		initrd_start = uboot_initrd_start;
 86		initrd_end = uboot_initrd_end;
 87		ROOT_DEV = Root_RAM0;
 88		pr_info("initrd at 0x%lx:0x%lx\n", initrd_start, initrd_end);
 89	}
 90#endif /* if defined(CONFIG_BLK_DEV_INITRD) */
 91}
 92
 93__init void process_uboot_commandline(char *commandp, int size)
 94{
 95	int len, n;
 96
 97	n = strnlen(commandp, size);
 98	commandp += n;
 99	len = size - n;
100	if (len) {
101		/* Add the whitespace separator */
102		*commandp++ = ' ';
103		len--;
104	}
105
106	parse_uboot_commandline(commandp, len);
107	commandp[len - 1] = 0;
108}