20080611-1520

1 files changed, 428 insertions, 0 deletions

diff --git a/os/boot/pc/devbios.c b/os/boot/pc/devbios.c
new file mode 100644
index 00000000..d178fe81
--- /dev/null
+++ b/os/boot/pc/devbios.c
@@ -0,0 +1,428 @@
+/*
+ * 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 int
+biosdiskcall(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.
+ */
+int
+biosinit(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;
+}
+
+void
+biosinitdev(int i, char *name)
+{
+	if(i >= bdrive.ndevs)
+		panic("biosinitdev");
+	sprint(name, "bios%d", i);
+}
+
+void
+biosprintdevs(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);
+}
+
+int
+biosboot(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 */
+long
+sectread(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 int
+dreset(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 int
+islba(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 Devsects
+getsize(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 Devbytes
+extgetsize(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;
+}
+
+long
+biosread(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;
+}
+
+vlong
+biosseek(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;
+}