/*
 * (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\"\n", 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)\n",
                       *(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)\n", 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\n",
               (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\n",
                       (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\n",
                               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)\n",
                               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)\n",
                       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)\n", 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);
}