/*
 *	CPU detetion based on DMI decode rev 1.2
 *
 *	(C) 2003 Nicolas Planel <nplanel@mandrakesoft.com>
 *      
 *	Licensed under the GNU Public license. If you want to use it in with
 *	another license just ask.
 */

#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <sys/mman.h>

typedef unsigned char u8;
typedef unsigned short u16;
typedef unsigned int u32;


#define DEFAULT_MEM_DEV "/dev/mem"

void *mem_chunk(u32 base, u32 len, const char *devmem)
{
    void *p;
    int fd;
    off_t mmoffset;
    void *mmp;

    if ((fd = open(devmem, O_RDONLY)) < 0)
	return NULL;

    if ((p = malloc(len)) == NULL)
	return NULL;

    mmoffset = base % getpagesize();
    mmp = mmap(0, mmoffset + len, PROT_READ, MAP_SHARED, fd, base - mmoffset);
    if (mmp == MAP_FAILED) {
	free(p);
	return NULL;
    }

    memcpy(p, (u8 *)mmp + mmoffset, len);
    munmap(mmp, mmoffset + len);
    close(fd);
    return p;
}


struct dmi_header
{
	u8	type;
	u8	length;
	u16	handle;
};

typedef int (*dmi_decode)(u8 * data);

static int decode_handle(u32 base, int len, int num, dmi_decode decode)
{
    u8 *buf;
    u8 *data;
    int i = 0;
    int ret = 0;

    if ((buf = mem_chunk(base, len, DEFAULT_MEM_DEV)) == NULL)
	return 0;

    data = buf;
    while(i<num && data+sizeof(struct dmi_header)<=buf+len)
    {
	u8 *next;
	struct dmi_header *dm = (struct dmi_header *)data;

	/* look for the next handle */
	next=data+dm->length;
	while(next-buf+1<len && (next[0]!=0 || next[1]!=0))
	    next++;
	next+=2;
	if(next-buf<=len)
	    ret += decode(data);
	else {
	    ret = 0; /* TRUNCATED */
	    break;
	}
	data=next;
	i++;
    }

    free(buf);
    return ret;
}

static int dmi_detect(dmi_decode decode) {
    u8 *buf;
    long fp;
    int ret;

    if ((buf = mem_chunk(0xf0000, 0x10000, DEFAULT_MEM_DEV)) == NULL) {
	perror("dmi_detect");
	exit(1);
    }

    for (fp = 0; fp <= 0xfff0; fp += 16) {
	if (memcmp(buf + fp, "_DMI_", 5) == 0) {
	    u8 *p = buf + fp;
	    u16 num = p[13]<<8|p[12];
	    u16 len = p[7]<<8|p[6];
	    u32 base = p[11]<<24|p[10]<<16|p[9]<<8|p[8];

	    ret = decode_handle(base, len, num, decode);
	    break;
	}
    }

    free(buf);
    return ret;
}

static int processor(u8 *data) {
	struct dmi_header *dm = (struct dmi_header *)data;

	if((dm->type == 4) && /*"Central Processor"*/(data[5] == 3)) {
		if(/*Processor Manufacturer*/data[7] != 0
		   && /*Populated*/(data[0x18] & (1 << 6))
		   && !/*Disabled {User:2h, BIOS:3}*/(data[0x18] & (1 << 1)))
			return 1;
	}
	return 0;
}

int intelDetectSMP(void) {
	return dmi_detect(processor) > 1;
}