/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include "u.h"#include "../port/lib.h"#include "mem.h"#include "dat.h"#include "fns.h"#include "io.h" #define VFLAG(...)	if(vflag) print(__VA_ARGS__) #define UPTR2INT(p)	((uintptr)(p)) static int vflag = 0; typedef struct BIOS32sdh {		/* BIOS32 Service Directory Header */	u8int	signature[4];		/* "_32_" */	u8int	physaddr[4];		/* physical address of entry point */	u8int	revision;	u8int	length;			/* of header in paragraphs */	u8int	checksum;		/* */	u8int	reserved[5];} BIOS32sdh; typedef struct BIOS32si {		/* BIOS32 Service Interface */	u8int*	base;			/* base address of service */	int	length;			/* length of service */	u32int	offset;			/* service entry-point from base */ 	u16int	ptr[3];			/* far pointer m16:32 */} BIOS32si; static Lock bios32lock;static u16int bios32ptr[3];static void* bios32entry; intbios32ci(BIOS32si* si, BIOS32ci* ci){	int r; 	lock(&bios32lock);	r = bios32call(ci, si->ptr);	unlock(&bios32lock); 	return r;} static void*rsdchecksum(void* addr, int length){	u8int *p, sum; 	sum = 0;	for(p = addr; length-- > 0; p++)		sum += *p;	if(sum == 0)		return addr; 	return nil;} static void*rsdscan(u8int* addr, int len, char* signature){	int sl;	u8int *e, *p; 	e = addr+len;	sl = strlen(signature);	for(p = addr; p+sl < e; p += 16){		if(memcmp(p, signature, sl))			continue;		return p;	} 	return nil;} static intbios32locate(void){	uintptr ptr;	BIOS32sdh *sdh; 	VFLAG("bios32link\n");	if((sdh = rsdscan(BIOSSEG(0xE000), 0x20000, "_32_")) == nil)		return -1;	if(rsdchecksum(sdh, sizeof(BIOS32sdh)) == nil)		return -1;	VFLAG("sdh @ %#p, entry %#ux\n", sdh, L32GET(sdh->physaddr)); 	bios32entry = vmap(L32GET(sdh->physaddr), 4096+1);	VFLAG("entry @ %#p\n", bios32entry);	ptr = UPTR2INT(bios32entry);	bios32ptr[0] = ptr & 0xffff;	bios32ptr[1] = (ptr>>16) & 0xffff;	bios32ptr[2] = KESEL;	VFLAG("bios32link: ptr %ux %ux %ux\n",		bios32ptr[0], bios32ptr[1], bios32ptr[2]); 	return 0;} voidBIOS32close(BIOS32si* si){	vunmap(si->base, si->length);	free(si);} BIOS32si*bios32open(char* id){	uint ptr;	BIOS32ci ci;	BIOS32si *si; 	lock(&bios32lock);	if(bios32ptr[2] == 0 && bios32locate() < 0){		unlock(&bios32lock);		return nil;	} 	VFLAG("bios32si: %s\n", id);	memset(&ci, 0, sizeof(BIOS32ci));	ci.eax = (id[3]<<24|(id[2]<<16)|(id[1]<<8)|id[0]); 	bios32call(&ci, bios32ptr);	unlock(&bios32lock); 	VFLAG("bios32si: eax %ux\n", ci.eax);	if(ci.eax & 0xff)		return nil;	VFLAG("bios32si: base %#ux length %#ux offset %#ux\n",		ci.ebx, ci.ecx, ci.edx); 	if((si = malloc(sizeof(BIOS32si))) == nil)		return nil;	if((si->base = vmap(ci.ebx, ci.ecx)) == nil){		free(si);		return nil;	}	si->length = ci.ecx; 	ptr = UPTR2INT(si->base)+ci.edx;	si->ptr[0] = ptr & 0xffff;	si->ptr[1] = (ptr>>16) & 0xffff;	si->ptr[2] = KESEL;	VFLAG("bios32si: eax entry %ux\n", ptr); 	return si;}