1 files changed, 165 insertions, 0 deletions
diff --git a/os/boot/pc/sdbios.c b/os/boot/pc/sdbios.c
new file mode 100644
index 00000000..fd4fe681
--- /dev/null
+++ b/os/boot/pc/sdbios.c
@@ -0,0 +1,165 @@
+/*
+ * boot driver for BIOS devices with partitions
+ * devbios must be called first
+ */
+#include "u.h"
+#include "lib.h"
+#include "mem.h"
+#include "dat.h"
+#include "fns.h"
+#include "io.h"
+#include "ureg.h"
+#include "error.h"
+
+#include "sd.h"
+#include "fs.h"
+
+long	biosread(Fs *, void *, long);
+vlong	biosseek(Fs *fs, vlong off);
+
+extern SDifc sdbiosifc;
+extern int onlybios0, biosinited;
+
+int
+biosverify(SDunit* )
+{
+	if (onlybios0 || !biosinited)
+		return 0;
+	return 1;
+}
+
+int
+biosonline(SDunit* unit)
+{
+	if (onlybios0 || !biosinited || !unit)
+		return 0;
+	unit->sectors = 1UL << 30;	/* a bunch */
+	unit->secsize = 512;		/* conventional */
+	return 1;
+}
+
+static int
+biosrio(SDreq* r)
+{
+	int nb;
+	long got;
+	vlong len, off;
+	uchar *p;
+	Fs fs;			/* just for fs->dev, which is zero */
+
+	if (onlybios0 || !biosinited)
+		return SDeio;
+	/*
+	 * Most SCSI commands can be passed unchanged except for
+	 * the padding on the end. The few which require munging
+	 * are not used internally. Mode select/sense(6) could be
+	 * converted to the 10-byte form but it's not worth the
+	 * effort. Read/write(6) are easy.
+	 */
+	r->rlen = 0;
+	r->status = SDok;
+	switch(r->cmd[0]){
+	case 0x08:			/* read */
+	case 0x28:			/* read */
+		if (r->cmd[0] == 0x08)
+			panic("biosrio: 0x08 read op\n");
+		off = r->cmd[2]<<24 | r->cmd[3]<<16 | r->cmd[4]<<8 | r->cmd[5];
+		nb = r->cmd[7]<<8 | r->cmd[8];	/* often 4 */
+		USED(nb);		/* is nb*512 == r->dlen? */
+		memset(&fs, 0, sizeof fs);
+		biosseek(&fs, off*512);
+		got = biosread(&fs, r->data, r->dlen);
+		if (got < 0)
+			r->status = SDeio;
+		else
+			r->rlen = got;
+		break;
+	case 0x0A:			/* write */
+	case 0x2A:			/* write */
+		r->status = SDeio;	/* boot programs don't write */
+		break;
+	case 0x25:			/* read capacity */
+		/*
+		 * Read capacity returns the LBA of the last sector.
+		 */
+		len = r->unit->sectors - 1;
+		p = r->data;
+		*p++ = len>>24;
+		*p++ = len>>16;
+		*p++ = len>>8;
+		*p++ = len;
+		len = r->unit->secsize;
+		*p++ = len>>24;
+		*p++ = len>>16;
+		*p++ = len>>8;
+		*p = len;
+		r->data = (char *)r->data + 8;
+		return SDok;
+	case 0x9E:			/* long read capacity */
+		/*
+		 * Read capacity returns the LBA of the last sector.
+		 */
+		len = r->unit->sectors - 1;
+		p = r->data;
+		*p++ = len>>56;
+		*p++ = len>>48;
+		*p++ = len>>40;
+		*p++ = len>>32;
+		*p++ = len>>24;
+		*p++ = len>>16;
+		*p++ = len>>8;
+		*p++ = len;
+		len = r->unit->secsize;
+		*p++ = len>>24;
+		*p++ = len>>16;
+		*p++ = len>>8;
+		*p = len;
+		r->data = (char *)r->data + 8;
+		return SDok;
+	/* ignore others */
+	}
+	return r->status;
+}
+
+SDev*
+biosid(SDev* sdev)
+{
+	for (; sdev; sdev = sdev->next)
+		if (sdev->ifc == &sdbiosifc)
+			sdev->idno = 'B';
+	return sdev;
+}
+
+static SDev*
+biospnp(void)
+{
+	SDev *sdev;
+
+	/* 9pxeload can't use bios int 13 calls; they wedge the machine */
+	if (pxe || getconf("*nobiosload") != nil || onlybios0 || !biosinited)
+		return nil;
+	if((sdev = malloc(sizeof(SDev))) != nil) {
+		sdev->ifc = &sdbiosifc;
+		sdev->index = -1;
+		sdev->nunit = 1;
+	}
+	return sdev;
+}
+
+SDifc sdbiosifc = {
+	"bios",				/* name */
+
+	biospnp,			/* pnp */
+	nil,				/* legacy */
+	biosid,				/* id */
+	nil,				/* enable */
+	nil,				/* disable */
+
+	biosverify,			/* verify */
+	biosonline,			/* online */
+	biosrio,			/* rio */
+	nil,				/* rctl */
+	nil,				/* wctl */
+
+	scsibio,			/* bio */
+};