bootcd.c

em86xx 完整启动程序,支持网络下载与串通下载

/*****************************************
 Copyright (c) 2002-2004
 Sigma Designs, Inc. All Rights Reserved
 Proprietary and Confidential
 *****************************************/

/* This file is part of the boot loader */

/*
 * bootcd.c
 *
 * Bootable CD-ROM format support
 *
 * Based on "El Torito" Bootable CD-ROM Format Specification v1.0
 * Modified from jasper boot loader by Ho Lee 03/24/2004
 */

#include "config.h"
#include "uart.h"
#include "io.h"
#include "system.h"
#include "util.h"
#include "hardware.h"
#include "em86xxapi.h"

#include "ide.h"
#include "atapi.h"
#include "bootcd.h"

// function protoytypes
static unsigned int check_boot_record(unsigned char *buf);
static int check_validation_entry(unsigned char *buf);
static int get_initial_entry(unsigned char *buf, unsigned int *psector, unsigned int *pnsector);

// return 0 if error
// return 4 bytes integer starting from buf + 0x47
unsigned int check_boot_record(unsigned char *buf)
{
    /* 
     * Boot Record Volume Descriptor 
     *
     * 0x00 : Boot record indicator, must be 0
     * 0x01 - 0x05 : "CD001"
     * 0x06 : Version of this descriptor, must be 1
     * 0x07 - 0x26 : "EL TORITO SPECIFICATION" padded with 0's
     * 0x27 - 0x46 : Unused, must be 0
     * 0x47 - 0x4a : Absolute pointer to first sector of Boot Catalog
     * 0x4b - 0x7ff : Unused, must be 0
     */

    uart_puts("CD-ROM Boot Sector :\n");

    if (buf[0] != 0) {
        uart_puts("  No boot sector found\n");
        return 0;
    }
    
    if (strncmp(buf + 1, "CD001", 5) != 0) {
        buf[1 + 5] = 0;
        uart_printf("  Wrong ISOID %s\n", buf + 1);
        return 0;
    }

    if (buf[6] != 1) {
        uart_puts("  Wrong version\n");
        return 0;
    }

    if (strncmp(buf + 7, "EL TORITO SPECIFICATION", 24) != 0) {
        buf[7 + 24] = 0;
        uart_printf("  Wrong ELTORITOID %s\n", buf + 7);
        return 0;
    }

    uart_printf("  Found Booting Catalog at sector %d\n", __read32(buf + 0x47));

    return __read32(buf + 0x47);
}

// return 0 if OK
int check_validation_entry(unsigned char *buf)
{
    /*
     * Validation Entry
     *
     * 0x00 : Header ID, must be 1
     * 0x01 : Platform ID
     * 0x02 - 0x03 : Reserved, must be 0
     * 0x04 - 0x1b : ID string
     * 0x1c - 0x1d : checksum
     * 0x1e : Key byte, must be 0x55
     * 0x1f : Key byte, must be 0xaa
     */

    uart_puts("CD-ROM Booting Catalog :\n");

    if (buf[0x00] != 1 || buf[0x02] != 0 || buf[0x03] != 0 || buf[0x1e] != 0x55 || buf[0x1f] != 0xaa) {
        uart_puts("  Invalid validation entry\n");
        return 1;
    }

#ifdef ELTORITO_PLATFORM_ID
    if (buf[1] != ELTORITO_PLATFORM_ID) {
        uart_printf("  Wrong Platform ID 0x%02x\n", buf[1]);
        return 2;
    }
#endif

#ifdef ELTORITO_ID_STRING
    if (strncmp(buf + 4, ELTORITO_ID_STRING, 26) != 0) {
        buf[4 + 26] = 0;
        uart_printf("  Wrong ID string %s\n", buf + 4);
        return 3;
    }
#endif

    uart_puts("  Validation entry is OK\n");

    return 0;
}

// return 0 if OK
int get_initial_entry(unsigned char *buf, unsigned int *psector, unsigned int *pnsector)
{
    /*
     * Initial/Default Entry
     *
     * 0x00 : Boot indicator, 0x88 = bootable, 0x00 = not bootable
     * 0x01 : Boot media type
     *        0x00 = no emulation
     *        0x01 : 1.2M diskette
     *        0x02 : 1.44M diskette
     *        0x04 : 2.88M diskette
     *        0x08 : harddisk
     * 0x02 - 0x03 : Load segment
     * 0x04 : System type
     * 0x05 : Unused, must be 0
     * 0x06 - 0x07 : Sector count
     * 0x08 - 0x0b : Load RBA
     */

    if (buf[0] != 0x88) {
        uart_puts("  Not bootable\n");
        return 1;
    }

    if (buf[1] != 0)
        uart_printf("  Boot media = %02x\n", buf[1]);

    *psector = *(unsigned int *) (buf + 8);
    *pnsector = *(unsigned short *) (buf + 6);

    uart_printf("  Image starts from sector %d, size is %d sectors\n", *psector, *pnsector);

    return 0;
}

int bootcd_load_image(int drive, unsigned long addr, unsigned long *image_size)
{
    unsigned char buffer[CDSECTOR_SIZE];
    unsigned int catalog_sector;
    unsigned int image_sector, image_nsector;
    unsigned int i;
    unsigned long loadaddr;

#ifdef CONFIG_ENABLE_NETWORK
    extern int net_dev_down(void);
#endif

    if (atapi_waitready(drive, 20000) != 0) {
        uart_puts("No disc detected\n");
        return 1;
    }

    // Read boot record volume descriptor (sector 17)
    if (atapi_readsector(drive, buffer, 17, 1) != 0) {
        uart_puts("Can't read boot record\n");
        return 2;
    }

    // Get booting catalog sector address
    if ((catalog_sector = check_boot_record(buffer)) == 0)
        return 3;

    // Read booting catalog
    if (atapi_readsector(drive, buffer, catalog_sector, 1) != 0) {
        uart_puts("Can't read booting catalog\n");
        return 5;
    }

    // Check validation entry
    if (check_validation_entry(buffer) != 0)
        return 6;

    // Get initial image sector and number of sectors
    if (get_initial_entry(buffer + 0x20, &image_sector, &image_nsector) != 0)
        return 7;

#ifdef CONFIG_ENABLE_NETWORK
    net_dev_down();
#endif

    // Load the image
    uart_puts("Loading");

    for (i = 0, loadaddr = addr; i < image_nsector; ++i) {
        atapi_readsector(drive, (void *) loadaddr, image_sector, 1);
        loadaddr += CDSECTOR_SIZE;
        ++image_sector;
        // shows dot at every 64KB
        if ((i & 0x1f) == 0)
            uart_putc('.');
    }

    uart_puts("\n");

    uart_printf("Loaded kernel to 0x%08lx from CD-ROM, size = %dKB\n",
        addr, (image_nsector * CDSECTOR_SIZE) >> 10);

    if (image_size)
	    *image_size = image_nsector * CDSECTOR_SIZE;

    return 0;
}