/*
 * (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 x86 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>
#include <asm/bootparam.h>
#include <asm/ic/sc520.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;

        struct setup_header *hdr = (struct setup_header *)(image + SETUP_SECTS_OFF);

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

        if (KERNEL_MAGIC != hdr->boot_flag) {
                printf("Error: Invalid Boot Flag (found 0x%04x, expected 0x%04x)\n",
                                hdr->boot_flag, KERNEL_MAGIC);
                return 0;
        } else {
                printf("Valid Boot Flag\n");
        }

        /* determine boot protocol version */
        if (KERNEL_V2_MAGIC == hdr->header) {
                printf("Magic signature found\n");

                bootproto = hdr->version;
        } else {
                /* Very old kernel */
                printf("Magic signature not found\n");
                bootproto = 0x0100;
        }

        /* determine size of setup */
        if (0 == hdr->setup_sects) {
                printf("Setup Sectors = 0 (defaulting to 4)\n");
                setup_size = 5 * 512;
        } else {
                setup_size = (hdr->setup_sects + 1) * 512;
        }

        printf("Setup Size = 0x%8.8lx\n", (ulong)setup_size);

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

        /* Determine image type */
        big_image = (bootproto >= 0x0200) && (hdr->loadflags & BIG_KERNEL_FLAG);

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

        /* load setup */
        printf("Moving Real-Mode Code to 0x%8.8lx (%d bytes)\n", (ulong)setup_base, setup_size);
        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);
        }

        /* We are now setting up the real-mode version of the header */
        hdr = (struct setup_header *)(setup_base + SETUP_SECTS_OFF);

        if (bootproto >= 0x0200) {
                hdr->type_of_loader = 8;

                if (hdr->setup_sects >= 15)
                        printf("Linux kernel version %s\n", (char *)
                                        (setup_base + (hdr->kernel_version + 0x200)));
                else
                        printf("Setup Sectors < 15 - Cannot print kernel version.\n");

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

                        hdr->ramdisk_image = initrd_addr;
                        hdr->ramdisk_size = initrd_size;
                }
        }

        if (bootproto >= 0x0201) {
                hdr->heap_end_ptr = HEAP_END_OFFSET;
                hdr->loadflags |= HEAP_FLAG;
        }

        if (bootproto >= 0x0202) {
                hdr->cmd_line_ptr = (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;

                hdr->setup_move_size = 0x9100;
        }

        if (bootproto >= 0x0204)
                kernel_size = hdr->syssize * 16;
        else
                kernel_size -= setup_size;


        if (big_image) {
                if ((kernel_size) > BZIMAGE_MAX_SIZE) {
                        printf("Error: bzImage kernel too big! (size: %ld, max: %d)\n",
                               kernel_size, BZIMAGE_MAX_SIZE);
                        return 0;
                }

        } else if ((kernel_size) > ZIMAGE_MAX_SIZE) {
                printf("Error: zImage kernel too big! (size: %ld, max: %d)\n",
                       kernel_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);


        memmove(load_address, image + setup_size, kernel_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.xes = regs.xds;
        regs.xss = regs.xds;
        regs.esp = 0x9000;
        regs.eflags = 0;
        enter_realmode(((u32)setup_base+SETUP_START_OFFSET)>>4, 0, &regs, &regs);
}

int do_zboot (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
        void *base_ptr;
        void *bzImage_addr = NULL;
        char *s;
        ulong bzImage_size = 0;

        disable_interrupts();

        /* Setup board for maximum PC/AT Compatibility */
        setup_pcat_compatibility();

        if (argc >= 2)
                /* argv[1] holds the address of the bzImage */
                s = argv[1];
        else
                s = getenv("fileaddr");

        if (s)
                bzImage_addr = (void *)simple_strtoul(s, NULL, 16);

        if (argc >= 3)
                /* argv[2] holds the size of the bzImage */
                bzImage_size = simple_strtoul(argv[2], NULL, 16);

        /* Lets look for*/
        base_ptr = load_zimage (bzImage_addr, bzImage_size, 0, 0, 0);

        if (NULL == base_ptr) {
                printf ("## Kernel loading failed ...\n");
        } else {
                printf ("## Transferring control to Linux (at address %08x) ...\n",
                        (u32)base_ptr);

                /* we assume that the kernel is in place */
                printf("\nStarting kernel ...\n\n");

                boot_zimage(base_ptr);
                /* does not return */
        }

        return -1;
}

U_BOOT_CMD(
        zboot, 2, 0,    do_zboot,
        "Boot bzImage",
        ""
);