move ide/legacy/hd.c to drivers/block/

This patch moves hd.c to drivers/block/

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Cc: rmk@arm.linux.org.uk
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

3 files changed, 840 insertions, 0 deletions

diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index 0d1d213..c390974 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -433,4 +433,28 @@ config VIRTIO_BLK
 	  This is the virtual block driver for virtio.  It can be used with
           lguest or QEMU based VMMs (like KVM or Xen).  Say Y or M.
 
+config BLK_DEV_HD
+	bool "Old hard disk (MFM/RLL/IDE) driver"
+	depends on HAVE_IDE
+	depends on !ARM || ARCH_RPC || ARCH_SHARK || BROKEN
+	help
+	  There are two drivers for MFM/RLL/IDE hard disks. Most people use
+	  the newer enhanced driver, but this old one is still around for two
+	  reasons. Some older systems have strange timing problems and seem to
+	  work only with the old driver (which itself does not work with some
+	  newer systems). The other reason is that the old driver is smaller,
+	  since it lacks the enhanced functionality of the new one. This makes
+	  it a good choice for systems with very tight memory restrictions, or
+	  for systems with only older MFM/RLL/ESDI drives. Choosing the old
+	  driver can save 13 KB or so of kernel memory.
+
+	  If you want to use this driver together with the new one you have
+	  to use "hda=noprobe hdb=noprobe" kernel parameters to prevent the new
+	  driver from probing the primary interface.
+
+	  If you are unsure, then just choose the Enhanced IDE/MFM/RLL driver
+	  instead of this one. For more detailed information, read the
+	  Disk-HOWTO, available from
+	  <http://www.tldp.org/docs.html#howto>.
+
 endif # BLK_DEV
diff --git a/drivers/block/Makefile b/drivers/block/Makefile
index 5e58430..204332b 100644
--- a/drivers/block/Makefile
+++ b/drivers/block/Makefile
@@ -29,5 +29,6 @@ obj-$(CONFIG_VIRTIO_BLK)	+= virtio_blk.o
 obj-$(CONFIG_VIODASD)		+= viodasd.o
 obj-$(CONFIG_BLK_DEV_SX8)	+= sx8.o
 obj-$(CONFIG_BLK_DEV_UB)	+= ub.o
+obj-$(CONFIG_BLK_DEV_HD)	+= hd.o
 
 obj-$(CONFIG_XEN_BLKDEV_FRONTEND)	+= xen-blkfront.o
diff --git a/drivers/block/hd.c b/drivers/block/hd.c
new file mode 100644
index 0000000..00b6956
--- /dev/null
+++ b/drivers/block/hd.c
@@ -0,0 +1,815 @@
+/*
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ * This is the low-level hd interrupt support. It traverses the
+ * request-list, using interrupts to jump between functions. As
+ * all the functions are called within interrupts, we may not
+ * sleep. Special care is recommended.
+ *
+ *  modified by Drew Eckhardt to check nr of hd's from the CMOS.
+ *
+ *  Thanks to Branko Lankester, lankeste@fwi.uva.nl, who found a bug
+ *  in the early extended-partition checks and added DM partitions
+ *
+ *  IRQ-unmask, drive-id, multiple-mode, support for ">16 heads",
+ *  and general streamlining by Mark Lord.
+ *
+ *  Removed 99% of above. Use Mark's ide driver for those options.
+ *  This is now a lightweight ST-506 driver. (Paul Gortmaker)
+ *
+ *  Modified 1995 Russell King for ARM processor.
+ *
+ *  Bugfix: max_sectors must be <= 255 or the wheels tend to come
+ *  off in a hurry once you queue things up - Paul G. 02/2001
+ */
+
+/* Uncomment the following if you want verbose error reports. */
+/* #define VERBOSE_ERRORS */
+
+#include <linux/blkdev.h>
+#include <linux/errno.h>
+#include <linux/signal.h>
+#include <linux/interrupt.h>
+#include <linux/timer.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/genhd.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/ioport.h>
+#include <linux/mc146818rtc.h> /* CMOS defines */
+#include <linux/init.h>
+#include <linux/blkpg.h>
+#include <linux/hdreg.h>
+
+#define REALLY_SLOW_IO
+#include <asm/system.h>
+#include <asm/io.h>
+#include <asm/uaccess.h>
+
+#ifdef __arm__
+#undef  HD_IRQ
+#endif
+#include <asm/irq.h>
+#ifdef __arm__
+#define HD_IRQ IRQ_HARDDISK
+#endif
+
+/* Hd controller regster ports */
+
+#define HD_DATA		0x1f0		/* _CTL when writing */
+#define HD_ERROR	0x1f1		/* see err-bits */
+#define HD_NSECTOR	0x1f2		/* nr of sectors to read/write */
+#define HD_SECTOR	0x1f3		/* starting sector */
+#define HD_LCYL		0x1f4		/* starting cylinder */
+#define HD_HCYL		0x1f5		/* high byte of starting cyl */
+#define HD_CURRENT	0x1f6		/* 101dhhhh , d=drive, hhhh=head */
+#define HD_STATUS	0x1f7		/* see status-bits */
+#define HD_FEATURE	HD_ERROR	/* same io address, read=error, write=feature */
+#define HD_PRECOMP	HD_FEATURE	/* obsolete use of this port - predates IDE */
+#define HD_COMMAND	HD_STATUS	/* same io address, read=status, write=cmd */
+
+#define HD_CMD		0x3f6		/* used for resets */
+#define HD_ALTSTATUS	0x3f6		/* same as HD_STATUS but doesn't clear irq */
+
+/* Bits of HD_STATUS */
+#define ERR_STAT		0x01
+#define INDEX_STAT		0x02
+#define ECC_STAT		0x04	/* Corrected error */
+#define DRQ_STAT		0x08
+#define SEEK_STAT		0x10
+#define SERVICE_STAT		SEEK_STAT
+#define WRERR_STAT		0x20
+#define READY_STAT		0x40
+#define BUSY_STAT		0x80
+
+/* Bits for HD_ERROR */
+#define MARK_ERR		0x01	/* Bad address mark */
+#define TRK0_ERR		0x02	/* couldn't find track 0 */
+#define ABRT_ERR		0x04	/* Command aborted */
+#define MCR_ERR			0x08	/* media change request */
+#define ID_ERR			0x10	/* ID field not found */
+#define MC_ERR			0x20	/* media changed */
+#define ECC_ERR			0x40	/* Uncorrectable ECC error */
+#define BBD_ERR			0x80	/* pre-EIDE meaning:  block marked bad */
+#define ICRC_ERR		0x80	/* new meaning:  CRC error during transfer */
+
+static DEFINE_SPINLOCK(hd_lock);
+static struct request_queue *hd_queue;
+
+#define MAJOR_NR HD_MAJOR
+#define QUEUE (hd_queue)
+#define CURRENT elv_next_request(hd_queue)
+
+#define TIMEOUT_VALUE	(6*HZ)
+#define	HD_DELAY	0
+
+#define MAX_ERRORS     16	/* Max read/write errors/sector */
+#define RESET_FREQ      8	/* Reset controller every 8th retry */
+#define RECAL_FREQ      4	/* Recalibrate every 4th retry */
+#define MAX_HD		2
+
+#define STAT_OK		(READY_STAT|SEEK_STAT)
+#define OK_STATUS(s)	(((s)&(STAT_OK|(BUSY_STAT|WRERR_STAT|ERR_STAT)))==STAT_OK)
+
+static void recal_intr(void);
+static void bad_rw_intr(void);
+
+static int reset;
+static int hd_error;
+
+/*
+ *  This struct defines the HD's and their types.
+ */
+struct hd_i_struct {
+	unsigned int head, sect, cyl, wpcom, lzone, ctl;
+	int unit;
+	int recalibrate;
+	int special_op;
+};
+
+#ifdef HD_TYPE
+static struct hd_i_struct hd_info[] = { HD_TYPE };
+static int NR_HD = ARRAY_SIZE(hd_info);
+#else
+static struct hd_i_struct hd_info[MAX_HD];
+static int NR_HD;
+#endif
+
+static struct gendisk *hd_gendisk[MAX_HD];
+
+static struct timer_list device_timer;
+
+#define TIMEOUT_VALUE (6*HZ)
+
+#define SET_TIMER							\
+	do {								\
+		mod_timer(&device_timer, jiffies + TIMEOUT_VALUE);	\
+	} while (0)
+
+static void (*do_hd)(void) = NULL;
+#define SET_HANDLER(x) \
+if ((do_hd = (x)) != NULL) \
+	SET_TIMER; \
+else \
+	del_timer(&device_timer);
+
+
+#if (HD_DELAY > 0)
+
+#include <asm/i8253.h>
+
+unsigned long last_req;
+
+unsigned long read_timer(void)
+{
+	unsigned long t, flags;
+	int i;
+
+	spin_lock_irqsave(&i8253_lock, flags);
+	t = jiffies * 11932;
+	outb_p(0, 0x43);
+	i = inb_p(0x40);
+	i |= inb(0x40) << 8;
+	spin_unlock_irqrestore(&i8253_lock, flags);
+	return(t - i);
+}
+#endif
+
+static void __init hd_setup(char *str, int *ints)
+{
+	int hdind = 0;
+
+	if (ints[0] != 3)
+		return;
+	if (hd_info[0].head != 0)
+		hdind = 1;
+	hd_info[hdind].head = ints[2];
+	hd_info[hdind].sect = ints[3];
+	hd_info[hdind].cyl = ints[1];
+	hd_info[hdind].wpcom = 0;
+	hd_info[hdind].lzone = ints[1];
+	hd_info[hdind].ctl = (ints[2] > 8 ? 8 : 0);
+	NR_HD = hdind+1;
+}
+
+static void dump_status(const char *msg, unsigned int stat)
+{
+	char *name = "hd?";
+	if (CURRENT)
+		name = CURRENT->rq_disk->disk_name;
+
+#ifdef VERBOSE_ERRORS
+	printk("%s: %s: status=0x%02x { ", name, msg, stat & 0xff);
+	if (stat & BUSY_STAT)	printk("Busy ");
+	if (stat & READY_STAT)	printk("DriveReady ");
+	if (stat & WRERR_STAT)	printk("WriteFault ");
+	if (stat & SEEK_STAT)	printk("SeekComplete ");
+	if (stat & DRQ_STAT)	printk("DataRequest ");
+	if (stat & ECC_STAT)	printk("CorrectedError ");
+	if (stat & INDEX_STAT)	printk("Index ");
+	if (stat & ERR_STAT)	printk("Error ");
+	printk("}\n");
+	if ((stat & ERR_STAT) == 0) {
+		hd_error = 0;
+	} else {
+		hd_error = inb(HD_ERROR);
+		printk("%s: %s: error=0x%02x { ", name, msg, hd_error & 0xff);
+		if (hd_error & BBD_ERR)		printk("BadSector ");
+		if (hd_error & ECC_ERR)		printk("UncorrectableError ");
+		if (hd_error & ID_ERR)		printk("SectorIdNotFound ");
+		if (hd_error & ABRT_ERR)	printk("DriveStatusError ");
+		if (hd_error & TRK0_ERR)	printk("TrackZeroNotFound ");
+		if (hd_error & MARK_ERR)	printk("AddrMarkNotFound ");
+		printk("}");
+		if (hd_error & (BBD_ERR|ECC_ERR|ID_ERR|MARK_ERR)) {
+			printk(", CHS=%d/%d/%d", (inb(HD_HCYL)<<8) + inb(HD_LCYL),
+				inb(HD_CURRENT) & 0xf, inb(HD_SECTOR));
+			if (CURRENT)
+				printk(", sector=%ld", CURRENT->sector);
+		}
+		printk("\n");
+	}
+#else
+	printk("%s: %s: status=0x%02x.\n", name, msg, stat & 0xff);
+	if ((stat & ERR_STAT) == 0) {
+		hd_error = 0;
+	} else {
+		hd_error = inb(HD_ERROR);
+		printk("%s: %s: error=0x%02x.\n", name, msg, hd_error & 0xff);
+	}
+#endif
+}
+
+static void check_status(void)
+{
+	int i = inb_p(HD_STATUS);
+
+	if (!OK_STATUS(i)) {
+		dump_status("check_status", i);
+		bad_rw_intr();
+	}
+}
+
+static int controller_busy(void)
+{
+	int retries = 100000;
+	unsigned char status;
+
+	do {
+		status = inb_p(HD_STATUS);
+	} while ((status & BUSY_STAT) && --retries);
+	return status;
+}
+
+static int status_ok(void)
+{
+	unsigned char status = inb_p(HD_STATUS);
+
+	if (status & BUSY_STAT)
+		return 1;	/* Ancient, but does it make sense??? */
+	if (status & WRERR_STAT)
+		return 0;
+	if (!(status & READY_STAT))
+		return 0;
+	if (!(status & SEEK_STAT))
+		return 0;
+	return 1;
+}
+
+static int controller_ready(unsigned int drive, unsigned int head)
+{
+	int retry = 100;
+
+	do {
+		if (controller_busy() & BUSY_STAT)
+			return 0;
+		outb_p(0xA0 | (drive<<4) | head, HD_CURRENT);
+		if (status_ok())
+			return 1;
+	} while (--retry);
+	return 0;
+}
+
+static void hd_out(struct hd_i_struct *disk,
+		   unsigned int nsect,
+		   unsigned int sect,
+		   unsigned int head,
+		   unsigned int cyl,
+		   unsigned int cmd,
+		   void (*intr_addr)(void))
+{
+	unsigned short port;
+
+#if (HD_DELAY > 0)
+	while (read_timer() - last_req < HD_DELAY)
+		/* nothing */;
+#endif
+	if (reset)
+		return;
+	if (!controller_ready(disk->unit, head)) {
+		reset = 1;
+		return;
+	}
+	SET_HANDLER(intr_addr);
+	outb_p(disk->ctl, HD_CMD);
+	port = HD_DATA;
+	outb_p(disk->wpcom >> 2, ++port);
+	outb_p(nsect, ++port);
+	outb_p(sect, ++port);
+	outb_p(cyl, ++port);
+	outb_p(cyl >> 8, ++port);
+	outb_p(0xA0 | (disk->unit << 4) | head, ++port);
+	outb_p(cmd, ++port);
+}
+
+static void hd_request (void);
+
+static int drive_busy(void)
+{
+	unsigned int i;
+	unsigned char c;
+
+	for (i = 0; i < 500000 ; i++) {
+		c = inb_p(HD_STATUS);
+		if ((c & (BUSY_STAT | READY_STAT | SEEK_STAT)) == STAT_OK)
+			return 0;
+	}
+	dump_status("reset timed out", c);
+	return 1;
+}
+
+static void reset_controller(void)
+{
+	int	i;
+
+	outb_p(4, HD_CMD);
+	for (i = 0; i < 1000; i++) barrier();
+	outb_p(hd_info[0].ctl & 0x0f, HD_CMD);
+	for (i = 0; i < 1000; i++) barrier();
+	if (drive_busy())
+		printk("hd: controller still busy\n");
+	else if ((hd_error = inb(HD_ERROR)) != 1)
+		printk("hd: controller reset failed: %02x\n", hd_error);
+}
+
+static void reset_hd(void)
+{
+	static int i;
+
+repeat:
+	if (reset) {
+		reset = 0;
+		i = -1;
+		reset_controller();
+	} else {
+		check_status();
+		if (reset)
+			goto repeat;
+	}
+	if (++i < NR_HD) {
+		struct hd_i_struct *disk = &hd_info[i];
+		disk->special_op = disk->recalibrate = 1;
+		hd_out(disk, disk->sect, disk->sect, disk->head-1,
+			disk->cyl, WIN_SPECIFY, &reset_hd);
+		if (reset)
+			goto repeat;
+	} else
+		hd_request();
+}
+
+/*
+ * Ok, don't know what to do with the unexpected interrupts: on some machines
+ * doing a reset and a retry seems to result in an eternal loop. Right now I
+ * ignore it, and just set the timeout.
+ *
+ * On laptops (and "green" PCs), an unexpected interrupt occurs whenever the
+ * drive enters "idle", "standby", or "sleep" mode, so if the status looks
+ * "good", we just ignore the interrupt completely.
+ */
+static void unexpected_hd_interrupt(void)
+{
+	unsigned int stat = inb_p(HD_STATUS);
+
+	if (stat & (BUSY_STAT|DRQ_STAT|ECC_STAT|ERR_STAT)) {
+		dump_status("unexpected interrupt", stat);
+		SET_TIMER;
+	}
+}
+
+/*
+ * bad_rw_intr() now tries to be a bit smarter and does things
+ * according to the error returned by the controller.
+ * -Mika Liljeberg (liljeber@cs.Helsinki.FI)
+ */
+static void bad_rw_intr(void)
+{
+	struct request *req = CURRENT;
+	if (req != NULL) {
+		struct hd_i_struct *disk = req->rq_disk->private_data;
+		if (++req->errors >= MAX_ERRORS || (hd_error & BBD_ERR)) {
+			end_request(req, 0);
+			disk->special_op = disk->recalibrate = 1;
+		} else if (req->errors % RESET_FREQ == 0)
+			reset = 1;
+		else if ((hd_error & TRK0_ERR) || req->errors % RECAL_FREQ == 0)
+			disk->special_op = disk->recalibrate = 1;
+		/* Otherwise just retry */
+	}
+}
+
+static inline int wait_DRQ(void)
+{
+	int retries;
+	int stat;
+
+	for (retries = 0; retries < 100000; retries++) {
+		stat = inb_p(HD_STATUS);
+		if (stat & DRQ_STAT)
+			return 0;
+	}
+	dump_status("wait_DRQ", stat);
+	return -1;
+}
+
+static void read_intr(void)
+{
+	struct request *req;
+	int i, retries = 100000;
+
+	do {
+		i = (unsigned) inb_p(HD_STATUS);
+		if (i & BUSY_STAT)
+			continue;
+		if (!OK_STATUS(i))
+			break;
+		if (i & DRQ_STAT)
+			goto ok_to_read;
+	} while (--retries > 0);
+	dump_status("read_intr", i);
+	bad_rw_intr();
+	hd_request();
+	return;
+ok_to_read:
+	req = CURRENT;
+	insw(HD_DATA, req->buffer, 256);
+	req->sector++;
+	req->buffer += 512;
+	req->errors = 0;
+	i = --req->nr_sectors;
+	--req->current_nr_sectors;
+#ifdef DEBUG
+	printk("%s: read: sector %ld, remaining = %ld, buffer=%p\n",
+		req->rq_disk->disk_name, req->sector, req->nr_sectors,
+		req->buffer+512);
+#endif
+	if (req->current_nr_sectors <= 0)
+		end_request(req, 1);
+	if (i > 0) {
+		SET_HANDLER(&read_intr);
+		return;
+	}
+	(void) inb_p(HD_STATUS);
+#if (HD_DELAY > 0)
+	last_req = read_timer();
+#endif
+	if (elv_next_request(QUEUE))
+		hd_request();
+	return;
+}
+
+static void write_intr(void)
+{
+	struct request *req = CURRENT;
+	int i;
+	int retries = 100000;
+
+	do {
+		i = (unsigned) inb_p(HD_STATUS);
+		if (i & BUSY_STAT)
+			continue;
+		if (!OK_STATUS(i))
+			break;
+		if ((req->nr_sectors <= 1) || (i & DRQ_STAT))
+			goto ok_to_write;
+	} while (--retries > 0);
+	dump_status("write_intr", i);
+	bad_rw_intr();
+	hd_request();
+	return;
+ok_to_write:
+	req->sector++;
+	i = --req->nr_sectors;
+	--req->current_nr_sectors;
+	req->buffer += 512;
+	if (!i || (req->bio && req->current_nr_sectors <= 0))
+		end_request(req, 1);
+	if (i > 0) {
+		SET_HANDLER(&write_intr);
+		outsw(HD_DATA, req->buffer, 256);
+		local_irq_enable();
+	} else {
+#if (HD_DELAY > 0)
+		last_req = read_timer();
+#endif
+		hd_request();
+	}
+	return;
+}
+
+static void recal_intr(void)
+{
+	check_status();
+#if (HD_DELAY > 0)
+	last_req = read_timer();
+#endif
+	hd_request();
+}
+
+/*
+ * This is another of the error-routines I don't know what to do with. The
+ * best idea seems to just set reset, and start all over again.
+ */
+static void hd_times_out(unsigned long dummy)
+{
+	char *name;
+
+	do_hd = NULL;
+
+	if (!CURRENT)
+		return;
+
+	disable_irq(HD_IRQ);
+	local_irq_enable();
+	reset = 1;
+	name = CURRENT->rq_disk->disk_name;
+	printk("%s: timeout\n", name);
+	if (++CURRENT->errors >= MAX_ERRORS) {
+#ifdef DEBUG
+		printk("%s: too many errors\n", name);
+#endif
+		end_request(CURRENT, 0);
+	}
+	local_irq_disable();
+	hd_request();
+	enable_irq(HD_IRQ);
+}
+
+static int do_special_op(struct hd_i_struct *disk, struct request *req)
+{
+	if (disk->recalibrate) {
+		disk->recalibrate = 0;
+		hd_out(disk, disk->sect, 0, 0, 0, WIN_RESTORE, &recal_intr);
+		return reset;
+	}
+	if (disk->head > 16) {
+		printk("%s: cannot handle device with more than 16 heads - giving up\n", req->rq_disk->disk_name);
+		end_request(req, 0);
+	}
+	disk->special_op = 0;
+	return 1;
+}
+
+/*
+ * The driver enables interrupts as much as possible.  In order to do this,
+ * (a) the device-interrupt is disabled before entering hd_request(),
+ * and (b) the timeout-interrupt is disabled before the sti().
+ *
+ * Interrupts are still masked (by default) whenever we are exchanging
+ * data/cmds with a drive, because some drives seem to have very poor
+ * tolerance for latency during I/O. The IDE driver has support to unmask
+ * interrupts for non-broken hardware, so use that driver if required.
+ */
+static void hd_request(void)
+{
+	unsigned int block, nsect, sec, track, head, cyl;
+	struct hd_i_struct *disk;
+	struct request *req;
+
+	if (do_hd)
+		return;
+repeat:
+	del_timer(&device_timer);
+	local_irq_enable();
+
+	req = CURRENT;
+	if (!req) {
+		do_hd = NULL;
+		return;
+	}
+
+	if (reset) {
+		local_irq_disable();
+		reset_hd();
+		return;
+	}
+	disk = req->rq_disk->private_data;
+	block = req->sector;
+	nsect = req->nr_sectors;
+	if (block >= get_capacity(req->rq_disk) ||
+	    ((block+nsect) > get_capacity(req->rq_disk))) {
+		printk("%s: bad access: block=%d, count=%d\n",
+			req->rq_disk->disk_name, block, nsect);
+		end_request(req, 0);
+		goto repeat;
+	}
+
+	if (disk->special_op) {
+		if (do_special_op(disk, req))
+			goto repeat;
+		return;
+	}
+	sec   = block % disk->sect + 1;
+	track = block / disk->sect;
+	head  = track % disk->head;
+	cyl   = track / disk->head;
+#ifdef DEBUG
+	printk("%s: %sing: CHS=%d/%d/%d, sectors=%d, buffer=%p\n",
+		req->rq_disk->disk_name,
+		req_data_dir(req) == READ ? "read" : "writ",
+		cyl, head, sec, nsect, req->buffer);
+#endif
+	if (blk_fs_request(req)) {
+		switch (rq_data_dir(req)) {
+		case READ:
+			hd_out(disk, nsect, sec, head, cyl, WIN_READ,
+				&read_intr);
+			if (reset)
+				goto repeat;
+			break;
+		case WRITE:
+			hd_out(disk, nsect, sec, head, cyl, WIN_WRITE,
+				&write_intr);
+			if (reset)
+				goto repeat;
+			if (wait_DRQ()) {
+				bad_rw_intr();
+				goto repeat;
+			}
+			outsw(HD_DATA, req->buffer, 256);
+			break;
+		default:
+			printk("unknown hd-command\n");
+			end_request(req, 0);
+			break;
+		}
+	}
+}
+
+static void do_hd_request(struct request_queue *q)
+{
+	disable_irq(HD_IRQ);
+	hd_request();
+	enable_irq(HD_IRQ);
+}
+
+static int hd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
+{
+	struct hd_i_struct *disk = bdev->bd_disk->private_data;
+
+	geo->heads = disk->head;
+	geo->sectors = disk->sect;
+	geo->cylinders = disk->cyl;
+	return 0;
+}
+
+/*
+ * Releasing a block device means we sync() it, so that it can safely
+ * be forgotten about...
+ */
+
+static irqreturn_t hd_interrupt(int irq, void *dev_id)
+{
+	void (*handler)(void) = do_hd;
+
+	do_hd = NULL;
+	del_timer(&device_timer);
+	if (!handler)
+		handler = unexpected_hd_interrupt;
+	handler();
+	local_irq_enable();
+	return IRQ_HANDLED;
+}
+
+static struct block_device_operations hd_fops = {
+	.getgeo =	hd_getgeo,
+};
+
+/*
+ * This is the hard disk IRQ description. The IRQF_DISABLED in sa_flags
+ * means we run the IRQ-handler with interrupts disabled:  this is bad for
+ * interrupt latency, but anything else has led to problems on some
+ * machines.
+ *
+ * We enable interrupts in some of the routines after making sure it's
+ * safe.
+ */
+
+static int __init hd_init(void)
+{
+	int drive;
+
+	if (register_blkdev(MAJOR_NR, "hd"))
+		return -1;
+
+	hd_queue = blk_init_queue(do_hd_request, &hd_lock);
+	if (!hd_queue) {
+		unregister_blkdev(MAJOR_NR, "hd");
+		return -ENOMEM;
+	}
+
+	blk_queue_max_sectors(hd_queue, 255);
+	init_timer(&device_timer);
+	device_timer.function = hd_times_out;
+	blk_queue_hardsect_size(hd_queue, 512);
+
+	if (!NR_HD) {
+		/*
+		 * We don't know anything about the drive.  This means
+		 * that you *MUST* specify the drive parameters to the
+		 * kernel yourself.
+		 *
+		 * If we were on an i386, we used to read this info from
+		 * the BIOS or CMOS.  This doesn't work all that well,
+		 * since this assumes that this is a primary or secondary
+		 * drive, and if we're using this legacy driver, it's
+		 * probably an auxilliary controller added to recover
+		 * legacy data off an ST-506 drive.  Either way, it's
+		 * definitely safest to have the user explicitly specify
+		 * the information.
+		 */
+		printk("hd: no drives specified - use hd=cyl,head,sectors"
+			" on kernel command line\n");
+		goto out;
+	}
+
+	for (drive = 0 ; drive < NR_HD ; drive++) {
+		struct gendisk *disk = alloc_disk(64);
+		struct hd_i_struct *p = &hd_info[drive];
+		if (!disk)
+			goto Enomem;
+		disk->major = MAJOR_NR;
+		disk->first_minor = drive << 6;
+		disk->fops = &hd_fops;
+		sprintf(disk->disk_name, "hd%c", 'a'+drive);
+		disk->private_data = p;
+		set_capacity(disk, p->head * p->sect * p->cyl);
+		disk->queue = hd_queue;
+		p->unit = drive;
+		hd_gendisk[drive] = disk;
+		printk("%s: %luMB, CHS=%d/%d/%d\n",
+			disk->disk_name, (unsigned long)get_capacity(disk)/2048,
+			p->cyl, p->head, p->sect);
+	}
+
+	if (request_irq(HD_IRQ, hd_interrupt, IRQF_DISABLED, "hd", NULL)) {
+		printk("hd: unable to get IRQ%d for the hard disk driver\n",
+			HD_IRQ);
+		goto out1;
+	}
+	if (!request_region(HD_DATA, 8, "hd")) {
+		printk(KERN_WARNING "hd: port 0x%x busy\n", HD_DATA);
+		goto out2;
+	}
+	if (!request_region(HD_CMD, 1, "hd(cmd)")) {
+		printk(KERN_WARNING "hd: port 0x%x busy\n", HD_CMD);
+		goto out3;
+	}
+
+	/* Let them fly */
+	for (drive = 0; drive < NR_HD; drive++)
+		add_disk(hd_gendisk[drive]);
+
+	return 0;
+
+out3:
+	release_region(HD_DATA, 8);
+out2:
+	free_irq(HD_IRQ, NULL);
+out1:
+	for (drive = 0; drive < NR_HD; drive++)
+		put_disk(hd_gendisk[drive]);
+	NR_HD = 0;
+out:
+	del_timer(&device_timer);
+	unregister_blkdev(MAJOR_NR, "hd");
+	blk_cleanup_queue(hd_queue);
+	return -1;
+Enomem:
+	while (drive--)
+		put_disk(hd_gendisk[drive]);
+	goto out;
+}
+
+static int __init parse_hd_setup(char *line)
+{
+	int ints[6];
+
+	(void) get_options(line, ARRAY_SIZE(ints), ints);
+	hd_setup(NULL, ints);
+
+	return 1;
+}
+__setup("hd=", parse_hd_setup);
+
+late_initcall(hd_init);