/*
   * (C) Copyright 2002
   * Daniel Engström, Omicron Ceti AB, daniel@omicron.se

   *

   * 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
   */

  /*

   * Linux i386 zImage and bzImage loading

   *
   * based on the procdure described in

   * linux/Documentation/i386/boot.txt
   */
  
  #include <common.h>
  #include <asm/io.h>
  #include <asm/ptrace.h>
  #include <asm/zimage.h>
  #include <asm/realmode.h>
  #include <asm/byteorder.h>
  
  /*
   * Memory lay-out:

   *

   * relative to setup_base (which is 0x90000 currently)

   *
   *	0x0000-0x7FFF	Real mode kernel

   *	0x8000-0x8FFF	Stack and heap
   *	0x9000-0x90FF	Kernel command line
   */
  #define DEFAULT_SETUP_BASE  0x90000
  #define COMMAND_LINE_OFFSET 0x9000
  #define HEAP_END_OFFSET     0x8e00
  
  #define COMMAND_LINE_SIZE   2048
  
  static void build_command_line(char *command_line, int auto_boot)
  {
  	char *env_command_line;

  	command_line[0] = '\0';

  	env_command_line =  getenv("bootargs");

  	/* set console= argument if we use a serial console */
  	if (NULL == strstr(env_command_line, "console=")) {
  		if (0==strcmp(getenv("stdout"), "serial")) {

  			/* We seem to use serial console */

  			sprintf(command_line, "console=ttyS0,%s ",

  				 getenv("baudrate"));
  		}
  	}

  	if (auto_boot) {
  		strcat(command_line, "auto ");
  	}

  	if (NULL != env_command_line) {
  		strcat(command_line, env_command_line);

  	}

  	printf("Kernel command line: \"%s\"
  ", command_line);
  }

  void *load_zimage(char *image, unsigned long kernel_size,

  		  unsigned long initrd_addr, unsigned long initrd_size,
  		  int auto_boot)
  {

  	void *setup_base;

  	int setup_size;
  	int bootproto;
  	int big_image;
  	void *load_address;

  	setup_base = (void*)DEFAULT_SETUP_BASE;	/* base address for real-mode segment */

  
  	if (KERNEL_MAGIC != *(u16*)(image + BOOT_FLAG_OFF)) {

  		printf("Error: Invalid kernel magic (found 0x%04x, expected 0xaa55)
  ",
  		       *(u16*)(image + BOOT_FLAG_OFF));
  		return 0;
  	}

  	/* determine boot protocol version */
  	if (KERNEL_V2_MAGIC == *(u32*)(image+HEADER_OFF)) {
  		bootproto = *(u16*)(image+VERSION_OFF);
  	} else {
  		/* Very old kernel */
  		bootproto = 0x0100;
  	}

  	/* determine size of setup */
  	if (0 == *(u8*)(image + SETUP_SECTS_OFF)) {
  		setup_size = 5 * 512;
  	} else {
  		setup_size = (*(u8*)(image + SETUP_SECTS_OFF) + 1) * 512;
  	}

  	if (setup_size > SETUP_MAX_SIZE) {
  		printf("Error: Setup is too large (%d bytes)
  ", setup_size);
  	}

  	/* Determine image type */

  	big_image = (bootproto >= 0x0200) && (*(u8*)(image + LOADFLAGS_OFF) & BIG_KERNEL_FLAG);

  	/* Derermine load address */
  	load_address = (void*)(big_image ? BZIMAGE_LOAD_ADDR:ZIMAGE_LOAD_ADDR);

  	/* load setup */
  	memmove(setup_base, image, setup_size);

  
  	printf("Using boot protocol version %x.%02x
  ",

  	       (bootproto & 0xff00) >> 8, bootproto & 0xff);

  
  
  	if (bootproto == 0x0100) {

  		*(u16*)(setup_base + CMD_LINE_MAGIC_OFF) = COMMAND_LINE_MAGIC;

  		*(u16*)(setup_base + CMD_LINE_OFFSET_OFF) = COMMAND_LINE_OFFSET;

  		/* A very old kernel MUST have its real-mode code
  		 * loaded at 0x90000 */

  		if ((u32)setup_base != 0x90000) {
  			/* Copy the real-mode kernel */
  			memmove((void*)0x90000, setup_base, setup_size);
  			/* Copy the command line */

  			memmove((void*)0x99000, setup_base+COMMAND_LINE_OFFSET,

  			       COMMAND_LINE_SIZE);

  			setup_base = (void*)0x90000;		 /* Relocated */
  		}

  		/* It is recommended to clear memory up to the 32K mark */
  		memset((void*)0x90000 + setup_size, 0, SETUP_MAX_SIZE-setup_size);
  	}

  	if (bootproto >= 0x0200) {
  		*(u8*)(setup_base + TYPE_OF_LOADER_OFF) = 0xff;

  		printf("Linux kernel version %s
  ",
  		       (char*)(setup_base + SETUP_START_OFFSET +

  			       *(u16*)(setup_base + START_SYS_OFF + 2)));

  		if (initrd_addr) {
  			printf("Initial RAM disk at linear address 0x%08lx, size %ld bytes
  ",
  			       initrd_addr, initrd_size);

  			*(u32*)(setup_base + RAMDISK_IMAGE_OFF) = initrd_addr;
  			*(u32*)(setup_base + RAMDISK_SIZE_OFF)=initrd_size;
  		}
  	}

  	if (bootproto >= 0x0201) {
  		*(u16*)(setup_base + HEAP_END_PTR_OFF) = HEAP_END_OFFSET;

  		/* CAN_USE_HEAP */

  		*(u8*)(setup_base + LOADFLAGS_OFF) =

  			*(u8*)(setup_base + LOADFLAGS_OFF) | HEAP_FLAG;
  	}

  	if (bootproto >= 0x0202) {
  		*(u32*)(setup_base + CMD_LINE_PTR_OFF) = (u32)setup_base + COMMAND_LINE_OFFSET;
  	} else if (bootproto >= 0x0200) {
  		*(u16*)(setup_base + CMD_LINE_MAGIC_OFF) = COMMAND_LINE_MAGIC;

  		*(u16*)(setup_base + CMD_LINE_OFFSET_OFF) = COMMAND_LINE_OFFSET;

  		*(u16*)(setup_base + SETUP_MOVE_SIZE_OFF) = 0x9100;
  	}

  	if (big_image) {

  		if ((kernel_size - setup_size) > BZIMAGE_MAX_SIZE) {

  			printf("Error: bzImage kernel too big! (size: %ld, max: %d)
  ",
  			       kernel_size - setup_size, BZIMAGE_MAX_SIZE);
  			return 0;
  		}

  	} else if ((kernel_size - setup_size) > ZIMAGE_MAX_SIZE) {
  		printf("Error: zImage kernel too big! (size: %ld, max: %d)
  ",
  		       kernel_size - setup_size, ZIMAGE_MAX_SIZE);
  		return 0;
  	}

  	/* build command line at COMMAND_LINE_OFFSET */
  	build_command_line(setup_base + COMMAND_LINE_OFFSET, auto_boot);

  
  	printf("Loading %czImage at address 0x%08x (%ld bytes)
  ", big_image ? 'b' : ' ',

  	       (u32)load_address, kernel_size - setup_size);

  	memmove(load_address, image + setup_size, kernel_size - setup_size);

  	/* ready for booting */
  	return setup_base;
  }

  void boot_zimage(void *setup_base)
  {
  	struct pt_regs regs;

  	memset(&regs, 0, sizeof(struct pt_regs));
  	regs.xds = (u32)setup_base >> 4;

  	regs.xss = 0x9000;
  	regs.esp = 0x9000;

  	regs.eflags = 0;
  	enter_realmode(((u32)setup_base+SETUP_START_OFFSET)>>4, 0, &regs, &regs);
  }