/* * boot driver for BIOS devices */#include <u.h>#include "lib.h"#include "mem.h"#include "dat.h"#include "fns.h"#include "io.h"#include "ureg.h"#include "fs.h" typedef uvlong Devbytes, Devsects; typedef struct Biosdrive Biosdrive;	/* 1 drive -> ndevs */typedef struct Biosdev Biosdev; enum {	Debug = 0,	Maxdevs = 4, 	CF = 1,	Flopid = 0,			/* first floppy */	Baseid = 0x80,			/* first disk */ 	/* bios calls: int 13 disk services */	Biosinit	= 0,		/* initialise disk & floppy ctlrs */	Biosdrvsts,	Bioschsrdsects,	Biosdrvparam	= 8,	Biosctlrinit,	Biosreset	=  0xd,		/* reset disk */	Biosdrvrdy	= 0x10,	Biosdrvtype	= 0x15,	Biosckext	= 0x41,	Biosrdsect,	Biosedrvparam	= 0x48, 	/* disk types */	Typenone = 0,	Typedisk = 3,}; struct Biosdrive {	int	ndevs;};struct Biosdev {	Devbytes size;	Devbytes offset;	uchar	id;			/* drive number; e.g., 0x80 */	char	type;	ushort	sectsz;}; typedef struct Extread {	uchar	size;	uchar	unused1;	uchar	nsects;	uchar	unused2;	ulong	addr;		/* segment:offset */	uvlong	stsect;		/* starting sector */} Extread;typedef struct Edrvparam {	/* from edd 1.1 spec */	ushort	size;			/* max. buffer size */	ushort	flags;	ulong	physcyls;	ulong	physheads;	ulong	phystracksects;	uvlong	physsects;	ushort	sectsz;	void	*dpte;			/* ~0ull: invalid */ 	/* remainder from edd 3.0 spec */	ushort	key;			/* 0xbedd if present */	uchar	dpilen;	uchar	unused1;	ushort	unused2;	char	bustype[4];		/* "PCI" or "ISA" */	char	ifctype[8]; /* "ATA", "ATAPI", "SCSI", "USB", "1394", "FIBRE" */	uvlong	ifcpath;	uvlong	devpath;	uchar	unused3;	uchar	dpicksum;} Edrvparam; void	realmode(int intr, Ureg *ureg);		/* from trap.c */ int onlybios0;int biosinited; static Biosdev bdev[Maxdevs];static Biosdrive bdrive;static Ureg regs; static int	dreset(uchar drive);static Devbytes	extgetsize(Biosdev *);static Devsects	getsize(uchar drive, char *type);static int	islba(uchar drive); static intbiosdiskcall(Ureg *rp, uchar op, ulong bx, ulong dx, ulong si){	memset(rp, 0, sizeof *rp);	rp->ax = op << 8;	rp->bx = bx;	rp->dx = dx;			/* often drive id */	rp->si = si;	/* pass command in *rp, get results from there */	realmode(0x13, rp);	if (rp->flags & CF) {//		print("biosdiskcall: int 13 op 0x%ux drive 0x%lux failed, "//			"ah error code 0x%ux\n", op, dx, (uchar)(rp->ax >> 8));		return -1;	}	return 0;} /* * Find out what the bios knows about devices. * our boot device could be usb; ghod only knows where it will appear. */intbiosinit(void){	int devid, lba, mask, lastbit;	Devbytes size;	char type;	Biosdev *bdp;	static int beenhere; 	mask = lastbit = 0;	if (beenhere)		return mask;	beenhere = 1;	/* 9pxeload can't use bios int 13 calls; they wedge the machine */	if (pxe || getconf("*nobiosload") != nil || onlybios0 || !biosinited)		return mask;	for (devid = 0; devid < (1 << 8) && bdrive.ndevs < Maxdevs; devid++) {		lba = islba(devid);		if(!lba /* || devid != Baseid && dreset(devid) < 0 */ )			continue;		type = Typedisk;		/* HACK */		if (getsize(devid, &type) == 0) { /* no device, end of range */			devid &= ~0xf;			devid += 0x10;			devid--;			continue;		}		lastbit = 1 << bdrive.ndevs;		mask |= lastbit;		bdp = &bdev[bdrive.ndevs];		bdp->id = devid;		bdp->type = type;		size = extgetsize(bdp);		bdp->size = size;		print("bios%d: drive 0x%ux: %llud bytes, type %d\n",			bdrive.ndevs, devid, size, type);		bdrive.ndevs++;	}	/*	 * bioses seem to only be able to read from drive number 0x80	 * and certainly can't read from the highest drive number when we	 * call them, even if there is only one.  attempting to read from	 * the last drive number yields a hung machine or a two-minute pause.	 */	if (bdrive.ndevs > 0) {		if (bdrive.ndevs == 1) {			print("biosinit: sorry, only one bios drive; "				"can't read last one\n");			onlybios0 = 1;		} else			biosinited = 1;		bdrive.ndevs--;	/* omit last drive number; it can't be read */		mask &= ~lastbit;	}	return mask;} voidbiosinitdev(int i, char *name){	if(i >= bdrive.ndevs)		panic("biosinitdev");	sprint(name, "bios%d", i);} voidbiosprintdevs(int i){	if(i >= bdrive.ndevs){		print("got a print for %d, only got %d\n", i, bdrive.ndevs);		panic("biosprintdevs");	}	print(" bios%d", i);} intbiosboot(int dev, char *file, Boot *b){	Fs *fs; 	if(strncmp(file, "dos!", 4) == 0)		file += 4;	if(strchr(file, '!') != nil || strcmp(file, "") == 0) {		print("syntax is bios0!file\n");		return -1;	} 	fs = biosgetfspart(dev, "9fat", 1);	if(fs == nil)		return -1;	return fsboot(fs, file, b);} /* read n bytes at sector offset into a from drive id */longsectread(Biosdev *bdp, void *a, long n, Devsects offset){	uchar *biosparam, *cp;	Extread *erp; 	if(n < 0 || n > bdp->sectsz)		return -1;	if(Debug)		memset((uchar *)BIOSXCHG, 'r', bdp->sectsz); /* preclean the buffer. */ 	biosdiskcall(&regs, Biosdrvrdy, 0, bdp->id, 0); 	/* space for a BIG sector, just in case... */	biosparam = (uchar *)BIOSXCHG + 2*1024; 	/* read into BIOSXCHG */	erp = (Extread *)biosparam;	memset(erp, 0, sizeof *erp);	erp->size = sizeof *erp;	erp->nsects = 1;	erp->addr = PADDR(BIOSXCHG);	erp->stsect = offset;	if (biosdiskcall(&regs, Biosrdsect, 0, bdp->id, PADDR(erp)) < 0) {		print("sectread: bios failed to read %ld @ sector %lld of 0x%ux\n",			n, offset, bdp->id);		return -1;	} 	/* copy into caller's buffer */	memmove(a, (char *)BIOSXCHG, n);	if(Debug){		cp = (uchar *)BIOSXCHG;		print("-%ux %ux %ux %ux--%16.16s-\n",			cp[0], cp[1], cp[2], cp[3], (char *)cp + 480);	}	return n;} /* not tested yet. */static intdreset(uchar drive){if (0) {print("devbios: resetting disk controllers...");	biosdiskcall(&regs, Biosinit, 0, drive, 0);print("\n");}	return regs.ax? -1: 0;		/* ax!=0 on error */} static intislba(uchar drive){	if (biosdiskcall(&regs, Biosckext, 0x55aa, drive, 0) < 0)		return 0;	if(regs.bx != 0xaa55){		print("islba: buggy bios\n");		return 0;	}	if (Debug)		print("islba: drive 0x%ux extensions version %d.%d cx 0x%lux\n",			drive, (uchar)(regs.ax >> 8),			(uchar)regs.ax, regs.cx); /* cx: 4=edd, 1=use dap */	return regs.cx & 1;		/* dap bit */} /* * works so so... some floppies are 0x80+x when they shouldn't be, * and report lba even if they cannot... */static Devsectsgetsize(uchar id, char *typep){	int dtype; 	if (biosdiskcall(&regs, Biosdrvtype, 0x55aa, id, 0) < 0)		return 0; 	dtype = (ushort)regs.ax >> 8;	if(dtype == Typenone){		print("no such device 0x%ux of type %d\n", id, dtype);		return 0;	}	if(dtype != Typedisk){		print("non-disk device 0x%ux of type %d\n", id, dtype);		return 0;	}	*typep = dtype;	return (ushort)regs.cx | regs.dx << 16;} /* extended get size */static Devbytesextgetsize(Biosdev *bdp){	Edrvparam *edp; 	edp = (Edrvparam *)BIOSXCHG;	memset(edp, 0, sizeof *edp);	edp->size = sizeof *edp;	edp->dpilen = 36;	if (biosdiskcall(&regs, Biosedrvparam, 0, bdp->id, PADDR(edp)) < 0)		return 0;	if(Debug) {		print("extgetsize: drive 0x%ux info flags 0x%ux",			bdp->id, edp->flags);		if (edp->key == 0xbedd)			print(" %s %s", edp->bustype, edp->ifctype);		print("\n");	}	if (edp->sectsz <= 0) {		print("extgetsize: drive 0x%ux: non-positive sector size\n",			bdp->id);		edp->sectsz = 1;		/* don't divide by zero */	}	bdp->sectsz = edp->sectsz;	return edp->physsects * edp->sectsz;} longbiosread(Fs *fs, void *a, long n){	int want, got, part;	long totnr, stuck;	Devbytes offset;	Biosdev *bdp; 	if(fs->dev > bdrive.ndevs)		return -1;	if (n <= 0)		return n;	bdp = &bdev[fs->dev];	offset = bdp->offset;	stuck = 0;	for (totnr = 0; totnr < n && stuck < 4; totnr += got) {		want = bdp->sectsz;		if (totnr + want > n)			want = n - totnr;		if(Debug)			print("bios%d, read: %ld @ off %lld, want: %d, id: 0x%ux\n",				fs->dev, n, offset, want, bdp->id);		part = offset % bdp->sectsz;		if (part != 0) {	/* back up to start of sector */			offset -= part;			totnr  -= part;			if (totnr < 0) {				print("biosread: negative count %ld\n", totnr);				return -1;			}		}		if ((vlong)offset < 0) {			print("biosread: negative offset %lld\n", offset);			return -1;		}		got = sectread(bdp, (char *)a + totnr, want, offset/bdp->sectsz);		if(got <= 0){//			print("biosread: failed to read %ld @ off %lld of 0x%ux, "//				"want %d got %d\n",//				n, offset, bdp->id, want, got);			return -1;		}		offset += got;		bdp->offset = offset;		if (got < bdp->sectsz)			stuck++;	/* we'll have to re-read this sector */		else			stuck = 0;	}	return totnr;} vlongbiosseek(Fs *fs, vlong off){	if (off < 0) {		print("biosseek(fs, %lld) is illegal\n", off);		return -1;	}	if(fs->dev > bdrive.ndevs) {		print("biosseek: fs->dev %d > bdrive.ndevs %d\n",			fs->dev, bdrive.ndevs);		return -1;	}	bdev[fs->dev].offset = off;	/* do not know size... (yet) */	return off;} void *biosgetfspart(int i, char *name, int chatty){	static Fs fs; 	if(strcmp(name, "9fat") != 0){		if(chatty)			print("unknown partition bios%d!%s (use bios%d!9fat)\n",				i, name, i);		return nil;	} 	fs.dev = i;	fs.diskread = biosread;	fs.diskseek = biosseek; 	if(dosinit(&fs) < 0){		if(chatty)			print("bios%d!%s does not contain a FAT file system\n",				i, name);		return nil;	}	return &fs;}