u-boot/lib_m68k/bootm.c

/*
 * (C) Copyright 2003
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307	 USA
 *
 */

#include <common.h>
#include <command.h>
#include <image.h>
#include <zlib.h>
#include <bzlib.h>
#include <watchdog.h>
#include <environment.h>
#include <asm/byteorder.h>

DECLARE_GLOBAL_DATA_PTR;

#define PHYSADDR(x) x

#define LINUX_MAX_ENVS		256
#define LINUX_MAX_ARGS		256

#ifdef CONFIG_SHOW_BOOT_PROGRESS
# include <status_led.h>
# define SHOW_BOOT_PROGRESS(arg)	show_boot_progress(arg)
#else
# define SHOW_BOOT_PROGRESS(arg)
#endif

static ulong get_sp (void);

void do_bootm_linux(cmd_tbl_t * cmdtp, int flag,
		    int argc, char *argv[],
		    image_header_t *hdr, int verify)
{
	ulong sp_limit;

	ulong rd_data_start, rd_data_end, rd_len;
	ulong initrd_start, initrd_end;

	ulong cmd_start, cmd_end;
	char *cmdline;
	char *s;
	bd_t *kbd;
	void (*kernel) (bd_t *, ulong, ulong, ulong, ulong);

	/*
	 * Booting a (Linux) kernel image
	 *
	 * Allocate space for command line and board info - the
	 * address should be as high as possible within the reach of
	 * the kernel (see CFG_BOOTMAPSZ settings), but in unused
	 * memory, which means far enough below the current stack
	 * pointer.
	 */
	sp_limit = get_sp();

	debug("## Current stack ends at 0x%08lX ", sp_limit);

	sp_limit -= 2048;		/* just to be sure */
	if (sp_limit > CFG_BOOTMAPSZ)
		sp_limit = CFG_BOOTMAPSZ;
	sp_limit &= ~0xF;

	debug("=> set upper limit to 0x%08lX\n", sp_limit);

	cmdline = (char *)((sp_limit - CFG_BARGSIZE) & ~0xF);
	kbd = (bd_t *) (((ulong) cmdline - sizeof(bd_t)) & ~0xF);

	if ((s = getenv("bootargs")) == NULL)
		s = "";

	strcpy(cmdline, s);

	cmd_start = (ulong) & cmdline[0];
	cmd_end = cmd_start + strlen(cmdline);

	*kbd = *(gd->bd);

#ifdef	DEBUG
	printf("## cmdline at 0x%08lX ... 0x%08lX\n", cmd_start, cmd_end);

	do_bdinfo(NULL, 0, 0, NULL);
#endif

	if ((s = getenv("clocks_in_mhz")) != NULL) {
		/* convert all clock information to MHz */
		kbd->bi_intfreq /= 1000000L;
		kbd->bi_busfreq /= 1000000L;
	}

	/* find kernel */
	kernel =
	    (void (*)(bd_t *, ulong, ulong, ulong, ulong))image_get_ep (hdr);

	/* find ramdisk */
	get_ramdisk (cmdtp, flag, argc, argv, hdr, verify,
			IH_ARCH_M68K, &rd_data_start, &rd_data_end);

	rd_len = rd_data_end - rd_data_start;
	ramdisk_high (rd_data_start, rd_len, kdb, sp_limit, get_sp (),
			&initrd_start, &initrd_end);

	debug("## Transferring control to Linux (at address %08lx) ...\n",
	      (ulong) kernel);

	SHOW_BOOT_PROGRESS(15);

	/*
	 * Linux Kernel Parameters (passing board info data):
	 *   r3: ptr to board info data
	 *   r4: initrd_start or 0 if no initrd
	 *   r5: initrd_end - unused if r4 is 0
	 *   r6: Start of command line string
	 *   r7: End   of command line string
	 */
	(*kernel) (kbd, initrd_start, initrd_end, cmd_start, cmd_end);
	/* does not return */
}

static ulong get_sp (void)
{
	ulong sp;

	asm("movel %%a7, %%d0\n"
	    "movel %%d0, %0\n": "=d"(sp): :"%d0");

	return sp;
}