Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1288 insertions, 0 deletions

diff --git a/drivers/scsi/imm.c b/drivers/scsi/imm.c
new file mode 100644
index 000000000..7a499d621
--- /dev/null
+++ b/drivers/scsi/imm.c
@@ -0,0 +1,1288 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* imm.c   --  low level driver for the IOMEGA MatchMaker
+ * parallel port SCSI host adapter.
+ * 
+ * (The IMM is the embedded controller in the ZIP Plus drive.)
+ * 
+ * My unofficial company acronym list is 21 pages long:
+ *      FLA:    Four letter acronym with built in facility for
+ *              future expansion to five letters.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/blkdev.h>
+#include <linux/parport.h>
+#include <linux/workqueue.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <asm/io.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_host.h>
+
+/* The following #define is to avoid a clash with hosts.c */
+#define IMM_PROBE_SPP   0x0001
+#define IMM_PROBE_PS2   0x0002
+#define IMM_PROBE_ECR   0x0010
+#define IMM_PROBE_EPP17 0x0100
+#define IMM_PROBE_EPP19 0x0200
+
+
+typedef struct {
+	struct pardevice *dev;	/* Parport device entry         */
+	int base;		/* Actual port address          */
+	int base_hi;		/* Hi Base address for ECP-ISA chipset */
+	int mode;		/* Transfer mode                */
+	struct scsi_cmnd *cur_cmd;	/* Current queued command       */
+	struct delayed_work imm_tq;	/* Polling interrupt stuff       */
+	unsigned long jstart;	/* Jiffies at start             */
+	unsigned failed:1;	/* Failure flag                 */
+	unsigned dp:1;		/* Data phase present           */
+	unsigned rd:1;		/* Read data in data phase      */
+	unsigned wanted:1;	/* Parport sharing busy flag    */
+	unsigned int dev_no;	/* Device number		*/
+	wait_queue_head_t *waiting;
+	struct Scsi_Host *host;
+	struct list_head list;
+} imm_struct;
+
+static void imm_reset_pulse(unsigned int base);
+static int device_check(imm_struct *dev);
+
+#include "imm.h"
+
+static inline imm_struct *imm_dev(struct Scsi_Host *host)
+{
+	return *(imm_struct **)&host->hostdata;
+}
+
+static DEFINE_SPINLOCK(arbitration_lock);
+
+static void got_it(imm_struct *dev)
+{
+	dev->base = dev->dev->port->base;
+	if (dev->cur_cmd)
+		imm_scsi_pointer(dev->cur_cmd)->phase = 1;
+	else
+		wake_up(dev->waiting);
+}
+
+static void imm_wakeup(void *ref)
+{
+	imm_struct *dev = (imm_struct *) ref;
+	unsigned long flags;
+
+	spin_lock_irqsave(&arbitration_lock, flags);
+	if (dev->wanted) {
+		if (parport_claim(dev->dev) == 0) {
+			got_it(dev);
+			dev->wanted = 0;
+		}
+	}
+	spin_unlock_irqrestore(&arbitration_lock, flags);
+}
+
+static int imm_pb_claim(imm_struct *dev)
+{
+	unsigned long flags;
+	int res = 1;
+	spin_lock_irqsave(&arbitration_lock, flags);
+	if (parport_claim(dev->dev) == 0) {
+		got_it(dev);
+		res = 0;
+	}
+	dev->wanted = res;
+	spin_unlock_irqrestore(&arbitration_lock, flags);
+	return res;
+}
+
+static void imm_pb_dismiss(imm_struct *dev)
+{
+	unsigned long flags;
+	int wanted;
+	spin_lock_irqsave(&arbitration_lock, flags);
+	wanted = dev->wanted;
+	dev->wanted = 0;
+	spin_unlock_irqrestore(&arbitration_lock, flags);
+	if (!wanted)
+		parport_release(dev->dev);
+}
+
+static inline void imm_pb_release(imm_struct *dev)
+{
+	parport_release(dev->dev);
+}
+
+/* This is to give the imm driver a way to modify the timings (and other
+ * parameters) by writing to the /proc/scsi/imm/0 file.
+ * Very simple method really... (Too simple, no error checking :( )
+ * Reason: Kernel hackers HATE having to unload and reload modules for
+ * testing...
+ * Also gives a method to use a script to obtain optimum timings (TODO)
+ */
+static int imm_write_info(struct Scsi_Host *host, char *buffer, int length)
+{
+	imm_struct *dev = imm_dev(host);
+
+	if ((length > 5) && (strncmp(buffer, "mode=", 5) == 0)) {
+		dev->mode = simple_strtoul(buffer + 5, NULL, 0);
+		return length;
+	}
+	printk("imm /proc: invalid variable\n");
+	return -EINVAL;
+}
+
+static int imm_show_info(struct seq_file *m, struct Scsi_Host *host)
+{
+	imm_struct *dev = imm_dev(host);
+
+	seq_printf(m, "Version : %s\n", IMM_VERSION);
+	seq_printf(m, "Parport : %s\n", dev->dev->port->name);
+	seq_printf(m, "Mode    : %s\n", IMM_MODE_STRING[dev->mode]);
+	return 0;
+}
+
+#if IMM_DEBUG > 0
+#define imm_fail(x,y) printk("imm: imm_fail(%i) from %s at line %d\n",\
+	   y, __func__, __LINE__); imm_fail_func(x,y);
+static inline void
+imm_fail_func(imm_struct *dev, int error_code)
+#else
+static inline void
+imm_fail(imm_struct *dev, int error_code)
+#endif
+{
+	/* If we fail a device then we trash status / message bytes */
+	if (dev->cur_cmd) {
+		dev->cur_cmd->result = error_code << 16;
+		dev->failed = 1;
+	}
+}
+
+/*
+ * Wait for the high bit to be set.
+ * 
+ * In principle, this could be tied to an interrupt, but the adapter
+ * doesn't appear to be designed to support interrupts.  We spin on
+ * the 0x80 ready bit. 
+ */
+static unsigned char imm_wait(imm_struct *dev)
+{
+	int k;
+	unsigned short ppb = dev->base;
+	unsigned char r;
+
+	w_ctr(ppb, 0x0c);
+
+	k = IMM_SPIN_TMO;
+	do {
+		r = r_str(ppb);
+		k--;
+		udelay(1);
+	}
+	while (!(r & 0x80) && (k));
+
+	/*
+	 * STR register (LPT base+1) to SCSI mapping:
+	 *
+	 * STR      imm     imm
+	 * ===================================
+	 * 0x80     S_REQ   S_REQ
+	 * 0x40     !S_BSY  (????)
+	 * 0x20     !S_CD   !S_CD
+	 * 0x10     !S_IO   !S_IO
+	 * 0x08     (????)  !S_BSY
+	 *
+	 * imm      imm     meaning
+	 * ==================================
+	 * 0xf0     0xb8    Bit mask
+	 * 0xc0     0x88    ZIP wants more data
+	 * 0xd0     0x98    ZIP wants to send more data
+	 * 0xe0     0xa8    ZIP is expecting SCSI command data
+	 * 0xf0     0xb8    end of transfer, ZIP is sending status
+	 */
+	w_ctr(ppb, 0x04);
+	if (k)
+		return (r & 0xb8);
+
+	/* Counter expired - Time out occurred */
+	imm_fail(dev, DID_TIME_OUT);
+	printk("imm timeout in imm_wait\n");
+	return 0;		/* command timed out */
+}
+
+static int imm_negotiate(imm_struct * tmp)
+{
+	/*
+	 * The following is supposedly the IEEE 1284-1994 negotiate
+	 * sequence. I have yet to obtain a copy of the above standard
+	 * so this is a bit of a guess...
+	 *
+	 * A fair chunk of this is based on the Linux parport implementation
+	 * of IEEE 1284.
+	 *
+	 * Return 0 if data available
+	 *        1 if no data available
+	 */
+
+	unsigned short base = tmp->base;
+	unsigned char a, mode;
+
+	switch (tmp->mode) {
+	case IMM_NIBBLE:
+		mode = 0x00;
+		break;
+	case IMM_PS2:
+		mode = 0x01;
+		break;
+	default:
+		return 0;
+	}
+
+	w_ctr(base, 0x04);
+	udelay(5);
+	w_dtr(base, mode);
+	udelay(100);
+	w_ctr(base, 0x06);
+	udelay(5);
+	a = (r_str(base) & 0x20) ? 0 : 1;
+	udelay(5);
+	w_ctr(base, 0x07);
+	udelay(5);
+	w_ctr(base, 0x06);
+
+	if (a) {
+		printk
+		    ("IMM: IEEE1284 negotiate indicates no data available.\n");
+		imm_fail(tmp, DID_ERROR);
+	}
+	return a;
+}
+
+/* 
+ * Clear EPP timeout bit. 
+ */
+static inline void epp_reset(unsigned short ppb)
+{
+	int i;
+
+	i = r_str(ppb);
+	w_str(ppb, i);
+	w_str(ppb, i & 0xfe);
+}
+
+/* 
+ * Wait for empty ECP fifo (if we are in ECP fifo mode only)
+ */
+static inline void ecp_sync(imm_struct *dev)
+{
+	int i, ppb_hi = dev->base_hi;
+
+	if (ppb_hi == 0)
+		return;
+
+	if ((r_ecr(ppb_hi) & 0xe0) == 0x60) {	/* mode 011 == ECP fifo mode */
+		for (i = 0; i < 100; i++) {
+			if (r_ecr(ppb_hi) & 0x01)
+				return;
+			udelay(5);
+		}
+		printk("imm: ECP sync failed as data still present in FIFO.\n");
+	}
+}
+
+static int imm_byte_out(unsigned short base, const char *buffer, int len)
+{
+	int i;
+
+	w_ctr(base, 0x4);	/* apparently a sane mode */
+	for (i = len >> 1; i; i--) {
+		w_dtr(base, *buffer++);
+		w_ctr(base, 0x5);	/* Drop STROBE low */
+		w_dtr(base, *buffer++);
+		w_ctr(base, 0x0);	/* STROBE high + INIT low */
+	}
+	w_ctr(base, 0x4);	/* apparently a sane mode */
+	return 1;		/* All went well - we hope! */
+}
+
+static int imm_nibble_in(unsigned short base, char *buffer, int len)
+{
+	unsigned char l;
+	int i;
+
+	/*
+	 * The following is based on documented timing signals
+	 */
+	w_ctr(base, 0x4);
+	for (i = len; i; i--) {
+		w_ctr(base, 0x6);
+		l = (r_str(base) & 0xf0) >> 4;
+		w_ctr(base, 0x5);
+		*buffer++ = (r_str(base) & 0xf0) | l;
+		w_ctr(base, 0x4);
+	}
+	return 1;		/* All went well - we hope! */
+}
+
+static int imm_byte_in(unsigned short base, char *buffer, int len)
+{
+	int i;
+
+	/*
+	 * The following is based on documented timing signals
+	 */
+	w_ctr(base, 0x4);
+	for (i = len; i; i--) {
+		w_ctr(base, 0x26);
+		*buffer++ = r_dtr(base);
+		w_ctr(base, 0x25);
+	}
+	return 1;		/* All went well - we hope! */
+}
+
+static int imm_out(imm_struct *dev, char *buffer, int len)
+{
+	unsigned short ppb = dev->base;
+	int r = imm_wait(dev);
+
+	/*
+	 * Make sure that:
+	 * a) the SCSI bus is BUSY (device still listening)
+	 * b) the device is listening
+	 */
+	if ((r & 0x18) != 0x08) {
+		imm_fail(dev, DID_ERROR);
+		printk("IMM: returned SCSI status %2x\n", r);
+		return 0;
+	}
+	switch (dev->mode) {
+	case IMM_EPP_32:
+	case IMM_EPP_16:
+	case IMM_EPP_8:
+		epp_reset(ppb);
+		w_ctr(ppb, 0x4);
+#ifdef CONFIG_SCSI_IZIP_EPP16
+		if (!(((long) buffer | len) & 0x01))
+			outsw(ppb + 4, buffer, len >> 1);
+#else
+		if (!(((long) buffer | len) & 0x03))
+			outsl(ppb + 4, buffer, len >> 2);
+#endif
+		else
+			outsb(ppb + 4, buffer, len);
+		w_ctr(ppb, 0xc);
+		r = !(r_str(ppb) & 0x01);
+		w_ctr(ppb, 0xc);
+		ecp_sync(dev);
+		break;
+
+	case IMM_NIBBLE:
+	case IMM_PS2:
+		/* 8 bit output, with a loop */
+		r = imm_byte_out(ppb, buffer, len);
+		break;
+
+	default:
+		printk("IMM: bug in imm_out()\n");
+		r = 0;
+	}
+	return r;
+}
+
+static int imm_in(imm_struct *dev, char *buffer, int len)
+{
+	unsigned short ppb = dev->base;
+	int r = imm_wait(dev);
+
+	/*
+	 * Make sure that:
+	 * a) the SCSI bus is BUSY (device still listening)
+	 * b) the device is sending data
+	 */
+	if ((r & 0x18) != 0x18) {
+		imm_fail(dev, DID_ERROR);
+		return 0;
+	}
+	switch (dev->mode) {
+	case IMM_NIBBLE:
+		/* 4 bit input, with a loop */
+		r = imm_nibble_in(ppb, buffer, len);
+		w_ctr(ppb, 0xc);
+		break;
+
+	case IMM_PS2:
+		/* 8 bit input, with a loop */
+		r = imm_byte_in(ppb, buffer, len);
+		w_ctr(ppb, 0xc);
+		break;
+
+	case IMM_EPP_32:
+	case IMM_EPP_16:
+	case IMM_EPP_8:
+		epp_reset(ppb);
+		w_ctr(ppb, 0x24);
+#ifdef CONFIG_SCSI_IZIP_EPP16
+		if (!(((long) buffer | len) & 0x01))
+			insw(ppb + 4, buffer, len >> 1);
+#else
+		if (!(((long) buffer | len) & 0x03))
+			insl(ppb + 4, buffer, len >> 2);
+#endif
+		else
+			insb(ppb + 4, buffer, len);
+		w_ctr(ppb, 0x2c);
+		r = !(r_str(ppb) & 0x01);
+		w_ctr(ppb, 0x2c);
+		ecp_sync(dev);
+		break;
+
+	default:
+		printk("IMM: bug in imm_ins()\n");
+		r = 0;
+		break;
+	}
+	return r;
+}
+
+static int imm_cpp(unsigned short ppb, unsigned char b)
+{
+	/*
+	 * Comments on udelay values refer to the
+	 * Command Packet Protocol (CPP) timing diagram.
+	 */
+
+	unsigned char s1, s2, s3;
+	w_ctr(ppb, 0x0c);
+	udelay(2);		/* 1 usec - infinite */
+	w_dtr(ppb, 0xaa);
+	udelay(10);		/* 7 usec - infinite */
+	w_dtr(ppb, 0x55);
+	udelay(10);		/* 7 usec - infinite */
+	w_dtr(ppb, 0x00);
+	udelay(10);		/* 7 usec - infinite */
+	w_dtr(ppb, 0xff);
+	udelay(10);		/* 7 usec - infinite */
+	s1 = r_str(ppb) & 0xb8;
+	w_dtr(ppb, 0x87);
+	udelay(10);		/* 7 usec - infinite */
+	s2 = r_str(ppb) & 0xb8;
+	w_dtr(ppb, 0x78);
+	udelay(10);		/* 7 usec - infinite */
+	s3 = r_str(ppb) & 0x38;
+	/*
+	 * Values for b are:
+	 * 0000 00aa    Assign address aa to current device
+	 * 0010 00aa    Select device aa in EPP Winbond mode
+	 * 0010 10aa    Select device aa in EPP mode
+	 * 0011 xxxx    Deselect all devices
+	 * 0110 00aa    Test device aa
+	 * 1101 00aa    Select device aa in ECP mode
+	 * 1110 00aa    Select device aa in Compatible mode
+	 */
+	w_dtr(ppb, b);
+	udelay(2);		/* 1 usec - infinite */
+	w_ctr(ppb, 0x0c);
+	udelay(10);		/* 7 usec - infinite */
+	w_ctr(ppb, 0x0d);
+	udelay(2);		/* 1 usec - infinite */
+	w_ctr(ppb, 0x0c);
+	udelay(10);		/* 7 usec - infinite */
+	w_dtr(ppb, 0xff);
+	udelay(10);		/* 7 usec - infinite */
+
+	/*
+	 * The following table is electrical pin values.
+	 * (BSY is inverted at the CTR register)
+	 *
+	 *       BSY  ACK  POut SEL  Fault
+	 * S1    0    X    1    1    1
+	 * S2    1    X    0    1    1
+	 * S3    L    X    1    1    S
+	 *
+	 * L => Last device in chain
+	 * S => Selected
+	 *
+	 * Observered values for S1,S2,S3 are:
+	 * Disconnect => f8/58/78
+	 * Connect    => f8/58/70
+	 */
+	if ((s1 == 0xb8) && (s2 == 0x18) && (s3 == 0x30))
+		return 1;	/* Connected */
+	if ((s1 == 0xb8) && (s2 == 0x18) && (s3 == 0x38))
+		return 0;	/* Disconnected */
+
+	return -1;		/* No device present */
+}
+
+static inline int imm_connect(imm_struct *dev, int flag)
+{
+	unsigned short ppb = dev->base;
+
+	imm_cpp(ppb, 0xe0);	/* Select device 0 in compatible mode */
+	imm_cpp(ppb, 0x30);	/* Disconnect all devices */
+
+	if ((dev->mode == IMM_EPP_8) ||
+	    (dev->mode == IMM_EPP_16) ||
+	    (dev->mode == IMM_EPP_32))
+		return imm_cpp(ppb, 0x28);	/* Select device 0 in EPP mode */
+	return imm_cpp(ppb, 0xe0);	/* Select device 0 in compatible mode */
+}
+
+static void imm_disconnect(imm_struct *dev)
+{
+	imm_cpp(dev->base, 0x30);	/* Disconnect all devices */
+}
+
+static int imm_select(imm_struct *dev, int target)
+{
+	int k;
+	unsigned short ppb = dev->base;
+
+	/*
+	 * Firstly we want to make sure there is nothing
+	 * holding onto the SCSI bus.
+	 */
+	w_ctr(ppb, 0xc);
+
+	k = IMM_SELECT_TMO;
+	do {
+		k--;
+	} while ((r_str(ppb) & 0x08) && (k));
+
+	if (!k)
+		return 0;
+
+	/*
+	 * Now assert the SCSI ID (HOST and TARGET) on the data bus
+	 */
+	w_ctr(ppb, 0x4);
+	w_dtr(ppb, 0x80 | (1 << target));
+	udelay(1);
+
+	/*
+	 * Deassert SELIN first followed by STROBE
+	 */
+	w_ctr(ppb, 0xc);
+	w_ctr(ppb, 0xd);
+
+	/*
+	 * ACK should drop low while SELIN is deasserted.
+	 * FAULT should drop low when the SCSI device latches the bus.
+	 */
+	k = IMM_SELECT_TMO;
+	do {
+		k--;
+	}
+	while (!(r_str(ppb) & 0x08) && (k));
+
+	/*
+	 * Place the interface back into a sane state (status mode)
+	 */
+	w_ctr(ppb, 0xc);
+	return (k) ? 1 : 0;
+}
+
+static int imm_init(imm_struct *dev)
+{
+	if (imm_connect(dev, 0) != 1)
+		return -EIO;
+	imm_reset_pulse(dev->base);
+	mdelay(1);	/* Delay to allow devices to settle */
+	imm_disconnect(dev);
+	mdelay(1);	/* Another delay to allow devices to settle */
+	return device_check(dev);
+}
+
+static inline int imm_send_command(struct scsi_cmnd *cmd)
+{
+	imm_struct *dev = imm_dev(cmd->device->host);
+	int k;
+
+	/* NOTE: IMM uses byte pairs */
+	for (k = 0; k < cmd->cmd_len; k += 2)
+		if (!imm_out(dev, &cmd->cmnd[k], 2))
+			return 0;
+	return 1;
+}
+
+/*
+ * The bulk flag enables some optimisations in the data transfer loops,
+ * it should be true for any command that transfers data in integral
+ * numbers of sectors.
+ * 
+ * The driver appears to remain stable if we speed up the parallel port
+ * i/o in this function, but not elsewhere.
+ */
+static int imm_completion(struct scsi_cmnd *const cmd)
+{
+	/* Return codes:
+	 * -1     Error
+	 *  0     Told to schedule
+	 *  1     Finished data transfer
+	 */
+	struct scsi_pointer *scsi_pointer = imm_scsi_pointer(cmd);
+	imm_struct *dev = imm_dev(cmd->device->host);
+	unsigned short ppb = dev->base;
+	unsigned long start_jiffies = jiffies;
+
+	unsigned char r, v;
+	int fast, bulk, status;
+
+	v = cmd->cmnd[0];
+	bulk = ((v == READ_6) ||
+		(v == READ_10) || (v == WRITE_6) || (v == WRITE_10));
+
+	/*
+	 * We only get here if the drive is ready to comunicate,
+	 * hence no need for a full imm_wait.
+	 */
+	w_ctr(ppb, 0x0c);
+	r = (r_str(ppb) & 0xb8);
+
+	/*
+	 * while (device is not ready to send status byte)
+	 *     loop;
+	 */
+	while (r != (unsigned char) 0xb8) {
+		/*
+		 * If we have been running for more than a full timer tick
+		 * then take a rest.
+		 */
+		if (time_after(jiffies, start_jiffies + 1))
+			return 0;
+
+		/*
+		 * FAIL if:
+		 * a) Drive status is screwy (!ready && !present)
+		 * b) Drive is requesting/sending more data than expected
+		 */
+		if ((r & 0x88) != 0x88 || scsi_pointer->this_residual <= 0) {
+			imm_fail(dev, DID_ERROR);
+			return -1;	/* ERROR_RETURN */
+		}
+		/* determine if we should use burst I/O */
+		if (dev->rd == 0) {
+			fast = bulk && scsi_pointer->this_residual >=
+				IMM_BURST_SIZE ? IMM_BURST_SIZE : 2;
+			status = imm_out(dev, scsi_pointer->ptr, fast);
+		} else {
+			fast = bulk && scsi_pointer->this_residual >=
+				IMM_BURST_SIZE ? IMM_BURST_SIZE : 1;
+			status = imm_in(dev, scsi_pointer->ptr, fast);
+		}
+
+		scsi_pointer->ptr += fast;
+		scsi_pointer->this_residual -= fast;
+
+		if (!status) {
+			imm_fail(dev, DID_BUS_BUSY);
+			return -1;	/* ERROR_RETURN */
+		}
+		if (scsi_pointer->buffer && !scsi_pointer->this_residual) {
+			/* if scatter/gather, advance to the next segment */
+			if (scsi_pointer->buffers_residual--) {
+				scsi_pointer->buffer =
+					sg_next(scsi_pointer->buffer);
+				scsi_pointer->this_residual =
+				    scsi_pointer->buffer->length;
+				scsi_pointer->ptr = sg_virt(scsi_pointer->buffer);
+
+				/*
+				 * Make sure that we transfer even number of bytes
+				 * otherwise it makes imm_byte_out() messy.
+				 */
+				if (scsi_pointer->this_residual & 0x01)
+					scsi_pointer->this_residual++;
+			}
+		}
+		/* Now check to see if the drive is ready to comunicate */
+		w_ctr(ppb, 0x0c);
+		r = (r_str(ppb) & 0xb8);
+
+		/* If not, drop back down to the scheduler and wait a timer tick */
+		if (!(r & 0x80))
+			return 0;
+	}
+	return 1;		/* FINISH_RETURN */
+}
+
+/*
+ * Since the IMM itself doesn't generate interrupts, we use
+ * the scheduler's task queue to generate a stream of call-backs and
+ * complete the request when the drive is ready.
+ */
+static void imm_interrupt(struct work_struct *work)
+{
+	imm_struct *dev = container_of(work, imm_struct, imm_tq.work);
+	struct scsi_cmnd *cmd = dev->cur_cmd;
+	struct Scsi_Host *host = cmd->device->host;
+	unsigned long flags;
+
+	if (imm_engine(dev, cmd)) {
+		schedule_delayed_work(&dev->imm_tq, 1);
+		return;
+	}
+	/* Command must of completed hence it is safe to let go... */
+#if IMM_DEBUG > 0
+	switch ((cmd->result >> 16) & 0xff) {
+	case DID_OK:
+		break;
+	case DID_NO_CONNECT:
+		printk("imm: no device at SCSI ID %i\n", cmd->device->id);
+		break;
+	case DID_BUS_BUSY:
+		printk("imm: BUS BUSY - EPP timeout detected\n");
+		break;
+	case DID_TIME_OUT:
+		printk("imm: unknown timeout\n");
+		break;
+	case DID_ABORT:
+		printk("imm: told to abort\n");
+		break;
+	case DID_PARITY:
+		printk("imm: parity error (???)\n");
+		break;
+	case DID_ERROR:
+		printk("imm: internal driver error\n");
+		break;
+	case DID_RESET:
+		printk("imm: told to reset device\n");
+		break;
+	case DID_BAD_INTR:
+		printk("imm: bad interrupt (???)\n");
+		break;
+	default:
+		printk("imm: bad return code (%02x)\n",
+		       (cmd->result >> 16) & 0xff);
+	}
+#endif
+
+	if (imm_scsi_pointer(cmd)->phase > 1)
+		imm_disconnect(dev);
+
+	imm_pb_dismiss(dev);
+
+	spin_lock_irqsave(host->host_lock, flags);
+	dev->cur_cmd = NULL;
+	scsi_done(cmd);
+	spin_unlock_irqrestore(host->host_lock, flags);
+	return;
+}
+
+static int imm_engine(imm_struct *dev, struct scsi_cmnd *const cmd)
+{
+	struct scsi_pointer *scsi_pointer = imm_scsi_pointer(cmd);
+	unsigned short ppb = dev->base;
+	unsigned char l = 0, h = 0;
+	int retv, x;
+
+	/* First check for any errors that may have occurred
+	 * Here we check for internal errors
+	 */
+	if (dev->failed)
+		return 0;
+
+	switch (scsi_pointer->phase) {
+	case 0:		/* Phase 0 - Waiting for parport */
+		if (time_after(jiffies, dev->jstart + HZ)) {
+			/*
+			 * We waited more than a second
+			 * for parport to call us
+			 */
+			imm_fail(dev, DID_BUS_BUSY);
+			return 0;
+		}
+		return 1;	/* wait until imm_wakeup claims parport */
+
+	case 1:		/* Phase 1 - Connected */
+		imm_connect(dev, CONNECT_EPP_MAYBE);
+		scsi_pointer->phase++;
+		fallthrough;
+
+	case 2:		/* Phase 2 - We are now talking to the scsi bus */
+		if (!imm_select(dev, scmd_id(cmd))) {
+			imm_fail(dev, DID_NO_CONNECT);
+			return 0;
+		}
+		scsi_pointer->phase++;
+		fallthrough;
+
+	case 3:		/* Phase 3 - Ready to accept a command */
+		w_ctr(ppb, 0x0c);
+		if (!(r_str(ppb) & 0x80))
+			return 1;
+
+		if (!imm_send_command(cmd))
+			return 0;
+		scsi_pointer->phase++;
+		fallthrough;
+
+	case 4:		/* Phase 4 - Setup scatter/gather buffers */
+		if (scsi_bufflen(cmd)) {
+			scsi_pointer->buffer = scsi_sglist(cmd);
+			scsi_pointer->this_residual = scsi_pointer->buffer->length;
+			scsi_pointer->ptr = sg_virt(scsi_pointer->buffer);
+		} else {
+			scsi_pointer->buffer = NULL;
+			scsi_pointer->this_residual = 0;
+			scsi_pointer->ptr = NULL;
+		}
+		scsi_pointer->buffers_residual = scsi_sg_count(cmd) - 1;
+		scsi_pointer->phase++;
+		if (scsi_pointer->this_residual & 0x01)
+			scsi_pointer->this_residual++;
+		fallthrough;
+
+	case 5:		/* Phase 5 - Pre-Data transfer stage */
+		/* Spin lock for BUSY */
+		w_ctr(ppb, 0x0c);
+		if (!(r_str(ppb) & 0x80))
+			return 1;
+
+		/* Require negotiation for read requests */
+		x = (r_str(ppb) & 0xb8);
+		dev->rd = (x & 0x10) ? 1 : 0;
+		dev->dp = (x & 0x20) ? 0 : 1;
+
+		if ((dev->dp) && (dev->rd))
+			if (imm_negotiate(dev))
+				return 0;
+		scsi_pointer->phase++;
+		fallthrough;
+
+	case 6:		/* Phase 6 - Data transfer stage */
+		/* Spin lock for BUSY */
+		w_ctr(ppb, 0x0c);
+		if (!(r_str(ppb) & 0x80))
+			return 1;
+
+		if (dev->dp) {
+			retv = imm_completion(cmd);
+			if (retv == -1)
+				return 0;
+			if (retv == 0)
+				return 1;
+		}
+		scsi_pointer->phase++;
+		fallthrough;
+
+	case 7:		/* Phase 7 - Post data transfer stage */
+		if ((dev->dp) && (dev->rd)) {
+			if ((dev->mode == IMM_NIBBLE) || (dev->mode == IMM_PS2)) {
+				w_ctr(ppb, 0x4);
+				w_ctr(ppb, 0xc);
+				w_ctr(ppb, 0xe);
+				w_ctr(ppb, 0x4);
+			}
+		}
+		scsi_pointer->phase++;
+		fallthrough;
+
+	case 8:		/* Phase 8 - Read status/message */
+		/* Check for data overrun */
+		if (imm_wait(dev) != (unsigned char) 0xb8) {
+			imm_fail(dev, DID_ERROR);
+			return 0;
+		}
+		if (imm_negotiate(dev))
+			return 0;
+		if (imm_in(dev, &l, 1)) {	/* read status byte */
+			/* Check for optional message byte */
+			if (imm_wait(dev) == (unsigned char) 0xb8)
+				imm_in(dev, &h, 1);
+			cmd->result = (DID_OK << 16) | (l & STATUS_MASK);
+		}
+		if ((dev->mode == IMM_NIBBLE) || (dev->mode == IMM_PS2)) {
+			w_ctr(ppb, 0x4);
+			w_ctr(ppb, 0xc);
+			w_ctr(ppb, 0xe);
+			w_ctr(ppb, 0x4);
+		}
+		return 0;	/* Finished */
+
+	default:
+		printk("imm: Invalid scsi phase\n");
+	}
+	return 0;
+}
+
+static int imm_queuecommand_lck(struct scsi_cmnd *cmd)
+{
+	imm_struct *dev = imm_dev(cmd->device->host);
+
+	if (dev->cur_cmd) {
+		printk("IMM: bug in imm_queuecommand\n");
+		return 0;
+	}
+	dev->failed = 0;
+	dev->jstart = jiffies;
+	dev->cur_cmd = cmd;
+	cmd->result = DID_ERROR << 16;	/* default return code */
+	imm_scsi_pointer(cmd)->phase = 0;	/* bus free */
+
+	schedule_delayed_work(&dev->imm_tq, 0);
+
+	imm_pb_claim(dev);
+
+	return 0;
+}
+
+static DEF_SCSI_QCMD(imm_queuecommand)
+
+/*
+ * Apparently the disk->capacity attribute is off by 1 sector 
+ * for all disk drives.  We add the one here, but it should really
+ * be done in sd.c.  Even if it gets fixed there, this will still
+ * work.
+ */
+static int imm_biosparam(struct scsi_device *sdev, struct block_device *dev,
+			 sector_t capacity, int ip[])
+{
+	ip[0] = 0x40;
+	ip[1] = 0x20;
+	ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
+	if (ip[2] > 1024) {
+		ip[0] = 0xff;
+		ip[1] = 0x3f;
+		ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
+	}
+	return 0;
+}
+
+static int imm_abort(struct scsi_cmnd *cmd)
+{
+	imm_struct *dev = imm_dev(cmd->device->host);
+	/*
+	 * There is no method for aborting commands since Iomega
+	 * have tied the SCSI_MESSAGE line high in the interface
+	 */
+
+	switch (imm_scsi_pointer(cmd)->phase) {
+	case 0:		/* Do not have access to parport */
+	case 1:		/* Have not connected to interface */
+		dev->cur_cmd = NULL;	/* Forget the problem */
+		return SUCCESS;
+	default:		/* SCSI command sent, can not abort */
+		return FAILED;
+	}
+}
+
+static void imm_reset_pulse(unsigned int base)
+{
+	w_ctr(base, 0x04);
+	w_dtr(base, 0x40);
+	udelay(1);
+	w_ctr(base, 0x0c);
+	w_ctr(base, 0x0d);
+	udelay(50);
+	w_ctr(base, 0x0c);
+	w_ctr(base, 0x04);
+}
+
+static int imm_reset(struct scsi_cmnd *cmd)
+{
+	imm_struct *dev = imm_dev(cmd->device->host);
+
+	if (imm_scsi_pointer(cmd)->phase)
+		imm_disconnect(dev);
+	dev->cur_cmd = NULL;	/* Forget the problem */
+
+	imm_connect(dev, CONNECT_NORMAL);
+	imm_reset_pulse(dev->base);
+	mdelay(1);		/* device settle delay */
+	imm_disconnect(dev);
+	mdelay(1);		/* device settle delay */
+	return SUCCESS;
+}
+
+static int device_check(imm_struct *dev)
+{
+	/* This routine looks for a device and then attempts to use EPP
+	   to send a command. If all goes as planned then EPP is available. */
+
+	static char cmd[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
+	int loop, old_mode, status, k, ppb = dev->base;
+	unsigned char l;
+
+	old_mode = dev->mode;
+	for (loop = 0; loop < 8; loop++) {
+		/* Attempt to use EPP for Test Unit Ready */
+		if ((ppb & 0x0007) == 0x0000)
+			dev->mode = IMM_EPP_32;
+
+	      second_pass:
+		imm_connect(dev, CONNECT_EPP_MAYBE);
+		/* Select SCSI device */
+		if (!imm_select(dev, loop)) {
+			imm_disconnect(dev);
+			continue;
+		}
+		printk("imm: Found device at ID %i, Attempting to use %s\n",
+		       loop, IMM_MODE_STRING[dev->mode]);
+
+		/* Send SCSI command */
+		status = 1;
+		w_ctr(ppb, 0x0c);
+		for (l = 0; (l < 3) && (status); l++)
+			status = imm_out(dev, &cmd[l << 1], 2);
+
+		if (!status) {
+			imm_disconnect(dev);
+			imm_connect(dev, CONNECT_EPP_MAYBE);
+			imm_reset_pulse(dev->base);
+			udelay(1000);
+			imm_disconnect(dev);
+			udelay(1000);
+			if (dev->mode == IMM_EPP_32) {
+				dev->mode = old_mode;
+				goto second_pass;
+			}
+			printk("imm: Unable to establish communication\n");
+			return -EIO;
+		}
+		w_ctr(ppb, 0x0c);
+
+		k = 1000000;	/* 1 Second */
+		do {
+			l = r_str(ppb);
+			k--;
+			udelay(1);
+		} while (!(l & 0x80) && (k));
+
+		l &= 0xb8;
+
+		if (l != 0xb8) {
+			imm_disconnect(dev);
+			imm_connect(dev, CONNECT_EPP_MAYBE);
+			imm_reset_pulse(dev->base);
+			udelay(1000);
+			imm_disconnect(dev);
+			udelay(1000);
+			if (dev->mode == IMM_EPP_32) {
+				dev->mode = old_mode;
+				goto second_pass;
+			}
+			printk
+			    ("imm: Unable to establish communication\n");
+			return -EIO;
+		}
+		imm_disconnect(dev);
+		printk
+		    ("imm: Communication established at 0x%x with ID %i using %s\n",
+		     ppb, loop, IMM_MODE_STRING[dev->mode]);
+		imm_connect(dev, CONNECT_EPP_MAYBE);
+		imm_reset_pulse(dev->base);
+		udelay(1000);
+		imm_disconnect(dev);
+		udelay(1000);
+		return 0;
+	}
+	printk("imm: No devices found\n");
+	return -ENODEV;
+}
+
+/*
+ * imm cannot deal with highmem, so this causes all IO pages for this host
+ * to reside in low memory (hence mapped)
+ */
+static int imm_adjust_queue(struct scsi_device *device)
+{
+	blk_queue_bounce_limit(device->request_queue, BLK_BOUNCE_HIGH);
+	return 0;
+}
+
+static struct scsi_host_template imm_template = {
+	.module			= THIS_MODULE,
+	.proc_name		= "imm",
+	.show_info		= imm_show_info,
+	.write_info		= imm_write_info,
+	.name			= "Iomega VPI2 (imm) interface",
+	.queuecommand		= imm_queuecommand,
+	.eh_abort_handler	= imm_abort,
+	.eh_host_reset_handler	= imm_reset,
+	.bios_param		= imm_biosparam,
+	.this_id		= 7,
+	.sg_tablesize		= SG_ALL,
+	.can_queue		= 1,
+	.slave_alloc		= imm_adjust_queue,
+	.cmd_size		= sizeof(struct scsi_pointer),
+};
+
+/***************************************************************************
+ *                   Parallel port probing routines                        *
+ ***************************************************************************/
+
+static LIST_HEAD(imm_hosts);
+
+/*
+ * Finds the first available device number that can be alloted to the
+ * new imm device and returns the address of the previous node so that
+ * we can add to the tail and have a list in the ascending order.
+ */
+
+static inline imm_struct *find_parent(void)
+{
+	imm_struct *dev, *par = NULL;
+	unsigned int cnt = 0;
+
+	if (list_empty(&imm_hosts))
+		return NULL;
+
+	list_for_each_entry(dev, &imm_hosts, list) {
+		if (dev->dev_no != cnt)
+			return par;
+		cnt++;
+		par = dev;
+	}
+
+	return par;
+}
+
+static int __imm_attach(struct parport *pb)
+{
+	struct Scsi_Host *host;
+	imm_struct *dev, *temp;
+	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(waiting);
+	DEFINE_WAIT(wait);
+	int ports;
+	int modes, ppb;
+	int err = -ENOMEM;
+	struct pardev_cb imm_cb;
+
+	init_waitqueue_head(&waiting);
+
+	dev = kzalloc(sizeof(imm_struct), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+
+	dev->base = -1;
+	dev->mode = IMM_AUTODETECT;
+	INIT_LIST_HEAD(&dev->list);
+
+	temp = find_parent();
+	if (temp)
+		dev->dev_no = temp->dev_no + 1;
+
+	memset(&imm_cb, 0, sizeof(imm_cb));
+	imm_cb.private = dev;
+	imm_cb.wakeup = imm_wakeup;
+
+	dev->dev = parport_register_dev_model(pb, "imm", &imm_cb, dev->dev_no);
+	if (!dev->dev)
+		goto out;
+
+
+	/* Claim the bus so it remembers what we do to the control
+	 * registers. [ CTR and ECP ]
+	 */
+	err = -EBUSY;
+	dev->waiting = &waiting;
+	prepare_to_wait(&waiting, &wait, TASK_UNINTERRUPTIBLE);
+	if (imm_pb_claim(dev))
+		schedule_timeout(3 * HZ);
+	if (dev->wanted) {
+		printk(KERN_ERR "imm%d: failed to claim parport because "
+			"a pardevice is owning the port for too long "
+			"time!\n", pb->number);
+		imm_pb_dismiss(dev);
+		dev->waiting = NULL;
+		finish_wait(&waiting, &wait);
+		goto out1;
+	}
+	dev->waiting = NULL;
+	finish_wait(&waiting, &wait);
+	ppb = dev->base = dev->dev->port->base;
+	dev->base_hi = dev->dev->port->base_hi;
+	w_ctr(ppb, 0x0c);
+	modes = dev->dev->port->modes;
+
+	/* Mode detection works up the chain of speed
+	 * This avoids a nasty if-then-else-if-... tree
+	 */
+	dev->mode = IMM_NIBBLE;
+
+	if (modes & PARPORT_MODE_TRISTATE)
+		dev->mode = IMM_PS2;
+
+	/* Done configuration */
+
+	err = imm_init(dev);
+
+	imm_pb_release(dev);
+
+	if (err)
+		goto out1;
+
+	/* now the glue ... */
+	if (dev->mode == IMM_NIBBLE || dev->mode == IMM_PS2)
+		ports = 3;
+	else
+		ports = 8;
+
+	INIT_DELAYED_WORK(&dev->imm_tq, imm_interrupt);
+
+	err = -ENOMEM;
+	host = scsi_host_alloc(&imm_template, sizeof(imm_struct *));
+	if (!host)
+		goto out1;
+	host->io_port = pb->base;
+	host->n_io_port = ports;
+	host->dma_channel = -1;
+	host->unique_id = pb->number;
+	*(imm_struct **)&host->hostdata = dev;
+	dev->host = host;
+	if (!temp)
+		list_add_tail(&dev->list, &imm_hosts);
+	else
+		list_add_tail(&dev->list, &temp->list);
+	err = scsi_add_host(host, NULL);
+	if (err)
+		goto out2;
+	scsi_scan_host(host);
+	return 0;
+
+out2:
+	list_del_init(&dev->list);
+	scsi_host_put(host);
+out1:
+	parport_unregister_device(dev->dev);
+out:
+	kfree(dev);
+	return err;
+}
+
+static void imm_attach(struct parport *pb)
+{
+	__imm_attach(pb);
+}
+
+static void imm_detach(struct parport *pb)
+{
+	imm_struct *dev;
+	list_for_each_entry(dev, &imm_hosts, list) {
+		if (dev->dev->port == pb) {
+			list_del_init(&dev->list);
+			scsi_remove_host(dev->host);
+			scsi_host_put(dev->host);
+			parport_unregister_device(dev->dev);
+			kfree(dev);
+			break;
+		}
+	}
+}
+
+static struct parport_driver imm_driver = {
+	.name		= "imm",
+	.match_port	= imm_attach,
+	.detach		= imm_detach,
+	.devmodel	= true,
+};
+module_parport_driver(imm_driver);
+
+MODULE_LICENSE("GPL");