imm.c

Linux Kernel 2.6.9 for OMAP1710

	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) || (cmd->SCp.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
				&& (cmd->SCp.this_residual >=
				    IMM_BURST_SIZE)) ? IMM_BURST_SIZE : 2;
			status = imm_out(dev, cmd->SCp.ptr, fast);
		} else {
			fast = (bulk
				&& (cmd->SCp.this_residual >=
				    IMM_BURST_SIZE)) ? IMM_BURST_SIZE : 1;
			status = imm_in(dev, cmd->SCp.ptr, fast);
		}

		cmd->SCp.ptr += fast;
		cmd->SCp.this_residual -= fast;

		if (!status) {
			imm_fail(dev, DID_BUS_BUSY);
			return -1;	/* ERROR_RETURN */
		}
		if (cmd->SCp.buffer && !cmd->SCp.this_residual) {
			/* if scatter/gather, advance to the next segment */
			if (cmd->SCp.buffers_residual--) {
				cmd->SCp.buffer++;
				cmd->SCp.this_residual =
				    cmd->SCp.buffer->length;
				cmd->SCp.ptr =
				    page_address(cmd->SCp.buffer->page) +
				    cmd->SCp.buffer->offset;

				/*
				 * Make sure that we transfer even number of bytes
				 * otherwise it makes imm_byte_out() messy.
				 */
				if (cmd->SCp.this_residual & 0x01)
					cmd->SCp.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(void *data)
{
	imm_struct *dev = (imm_struct *) data;
	struct scsi_cmnd *cmd = dev->cur_cmd;
	struct Scsi_Host *host = cmd->device->host;
	unsigned long flags;

	if (!cmd) {
		printk("IMM: bug in imm_interrupt\n");
		return;
	}
	if (imm_engine(dev, cmd)) {
		INIT_WORK(&dev->imm_tq, imm_interrupt, (void *) dev);
		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 (cmd->SCp.phase > 1)
		imm_disconnect(dev);

	imm_pb_dismiss(dev);

	spin_lock_irqsave(host->host_lock, flags);
	dev->cur_cmd = NULL;
	cmd->scsi_done(cmd);
	spin_unlock_irqrestore(host->host_lock, flags);
	return;
}

static int imm_engine(imm_struct *dev, struct scsi_cmnd *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 (cmd->SCp.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 */
		/* Phase 1 - Connected */
	case 1:
		imm_connect(dev, CONNECT_EPP_MAYBE);
		cmd->SCp.phase++;

		/* Phase 2 - We are now talking to the scsi bus */
	case 2:
		if (!imm_select(dev, cmd->device->id)) {
			imm_fail(dev, DID_NO_CONNECT);
			return 0;
		}
		cmd->SCp.phase++;

		/* Phase 3 - Ready to accept a command */
	case 3:
		w_ctr(ppb, 0x0c);
		if (!(r_str(ppb) & 0x80))
			return 1;

		if (!imm_send_command(cmd))
			return 0;
		cmd->SCp.phase++;

		/* Phase 4 - Setup scatter/gather buffers */
	case 4:
		if (cmd->use_sg) {
			/* if many buffers are available, start filling the first */
			cmd->SCp.buffer =
			    (struct scatterlist *) cmd->request_buffer;
			cmd->SCp.this_residual = cmd->SCp.buffer->length;
			cmd->SCp.ptr =
			    page_address(cmd->SCp.buffer->page) +
			    cmd->SCp.buffer->offset;
		} else {
			/* else fill the only available buffer */
			cmd->SCp.buffer = NULL;
			cmd->SCp.this_residual = cmd->request_bufflen;
			cmd->SCp.ptr = cmd->request_buffer;
		}
		cmd->SCp.buffers_residual = cmd->use_sg - 1;
		cmd->SCp.phase++;
		if (cmd->SCp.this_residual & 0x01)
			cmd->SCp.this_residual++;
		/* Phase 5 - Pre-Data transfer stage */
	case 5:
		/* 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;
		cmd->SCp.phase++;

		/* Phase 6 - Data transfer stage */
	case 6:
		/* 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;
		}
		cmd->SCp.phase++;

		/* Phase 7 - Post data transfer stage */
	case 7:
		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);
			}
		}
		cmd->SCp.phase++;

		/* Phase 8 - Read status/message */
	case 8:
		/* 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 */
		break;

	default:
		printk("imm: Invalid scsi phase\n");
	}
	return 0;
}

static int imm_queuecommand(struct scsi_cmnd *cmd,
		void (*done)(struct scsi_cmnd *))
{
	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->scsi_done = done;
	cmd->result = DID_ERROR << 16;	/* default return code */
	cmd->SCp.phase = 0;	/* bus free */

	INIT_WORK(&dev->imm_tq, imm_interrupt, dev);
	schedule_work(&dev->imm_tq);

	imm_pb_claim(dev);

	return 0;
}

/*
 * 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 (cmd->SCp.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;
		break;
	default:		/* SCSI command sent, can not abort */
		return FAILED;
		break;
	}
}

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 (cmd->SCp.phase)
		imm_disconnect(dev);
	dev->cur_cmd = NULL;	/* Forget the problem */

	imm_connect(dev, CONNECT_NORMAL);
	imm_reset_pulse(dev->base);
	udelay(1000);		/* device settle delay */
	imm_disconnect(dev);
	udelay(1000);		/* 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;
}

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",
	.proc_info		= imm_proc_info,
	.name			= "Iomega VPI2 (imm) interface",
	.queuecommand		= imm_queuecommand,
	.eh_abort_handler	= imm_abort,
	.eh_bus_reset_handler	= imm_reset,
	.eh_host_reset_handler	= imm_reset,
	.bios_param		= imm_biosparam,
	.this_id		= 7,
	.sg_tablesize		= SG_ALL,
	.cmd_per_lun		= 1,
	.use_clustering		= ENABLE_CLUSTERING,
	.can_queue		= 1,
	.slave_alloc		= imm_adjust_queue,
};

/***************************************************************************
 *                   Parallel port probing routines                        *
 ***************************************************************************/

static LIST_HEAD(imm_hosts);

static int __imm_attach(struct parport *pb)
{
	struct Scsi_Host *host;
	imm_struct *dev;
	DECLARE_WAIT_QUEUE_HEAD(waiting);
	DEFINE_WAIT(wait);
	int ports;
	int modes, ppb;
	int err = -ENOMEM;

	init_waitqueue_head(&waiting);

	dev = kmalloc(sizeof(imm_struct), GFP_KERNEL);
	if (!dev)
		return -ENOMEM;

	memset(dev, 0, sizeof(imm_struct));

	dev->base = -1;
	dev->mode = IMM_AUTODETECT;
	INIT_LIST_HEAD(&dev->list);

	dev->dev = parport_register_device(pb, "imm", NULL, imm_wakeup,
						NULL, 0, dev);

	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_WORK(&dev->imm_tq, imm_interrupt, dev);

	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;
	list_add_tail(&dev->list, &imm_hosts);
	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",
	.attach	= imm_attach,
	.detach	= imm_detach,
};

static int __init imm_driver_init(void)
{
	printk("imm: Version %s\n", IMM_VERSION);
	return parport_register_driver(&imm_driver);
}

static void __exit imm_driver_exit(void)
{
	parport_unregister_driver(&imm_driver);
}

module_init(imm_driver_init);
module_exit(imm_driver_exit);

MODULE_LICENSE("GPL");