ppa.c

来自「linux 内核源代码」· C语言 代码 · 共 1,148 行 · 第 1/2 页

		 */
		if ((r & 0xc0) != 0xc0) {
			/* Wait for reconnection should be no more than 
			 * jiffy/2 = 5ms = 5000 loops
			 */
			unsigned long k = dev->recon_tmo;
			for (; k && ((r = (r_str(ppb) & 0xf0)) & 0xc0) != 0xc0;
			     k--)
				udelay(1);

			if (!k)
				return 0;
		}

		/* determine if we should use burst I/O */
		fast = (bulk && (cmd->SCp.this_residual >= PPA_BURST_SIZE))
		    ? PPA_BURST_SIZE : 1;

		if (r == (unsigned char) 0xc0)
			status = ppa_out(dev, cmd->SCp.ptr, fast);
		else
			status = ppa_in(dev, cmd->SCp.ptr, fast);

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

		if (!status) {
			ppa_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 = sg_virt(cmd->SCp.buffer);
			}
		}
		/* Now check to see if the drive is ready to comunicate */
		r = (r_str(ppb) & 0xf0);
		/* If not, drop back down to the scheduler and wait a timer tick */
		if (!(r & 0x80))
			return 0;
	}
	return 1;		/* FINISH_RETURN */
}

/*
 * Since the PPA 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 ppa_interrupt(struct work_struct *work)
{
	ppa_struct *dev = container_of(work, ppa_struct, ppa_tq.work);
	struct scsi_cmnd *cmd = dev->cur_cmd;

	if (!cmd) {
		printk(KERN_ERR "PPA: bug in ppa_interrupt\n");
		return;
	}
	if (ppa_engine(dev, cmd)) {
		schedule_delayed_work(&dev->ppa_tq, 1);
		return;
	}
	/* Command must of completed hence it is safe to let go... */
#if PPA_DEBUG > 0
	switch ((cmd->result >> 16) & 0xff) {
	case DID_OK:
		break;
	case DID_NO_CONNECT:
		printk(KERN_DEBUG "ppa: no device at SCSI ID %i\n", cmd->device->target);
		break;
	case DID_BUS_BUSY:
		printk(KERN_DEBUG "ppa: BUS BUSY - EPP timeout detected\n");
		break;
	case DID_TIME_OUT:
		printk(KERN_DEBUG "ppa: unknown timeout\n");
		break;
	case DID_ABORT:
		printk(KERN_DEBUG "ppa: told to abort\n");
		break;
	case DID_PARITY:
		printk(KERN_DEBUG "ppa: parity error (???)\n");
		break;
	case DID_ERROR:
		printk(KERN_DEBUG "ppa: internal driver error\n");
		break;
	case DID_RESET:
		printk(KERN_DEBUG "ppa: told to reset device\n");
		break;
	case DID_BAD_INTR:
		printk(KERN_WARNING "ppa: bad interrupt (???)\n");
		break;
	default:
		printk(KERN_WARNING "ppa: bad return code (%02x)\n",
		       (cmd->result >> 16) & 0xff);
	}
#endif

	if (cmd->SCp.phase > 1)
		ppa_disconnect(dev);

	ppa_pb_dismiss(dev);

	dev->cur_cmd = NULL;

	cmd->scsi_done(cmd);
}

static int ppa_engine(ppa_struct *dev, struct scsi_cmnd *cmd)
{
	unsigned short ppb = dev->base;
	unsigned char l = 0, h = 0;
	int retv;

	/* First check for any errors that may of 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
			 */
			ppa_fail(dev, DID_BUS_BUSY);
			return 0;
		}
		return 1;	/* wait until ppa_wakeup claims parport */
	case 1:		/* Phase 1 - Connected */
		{		/* Perform a sanity check for cable unplugged */
			int retv = 2;	/* Failed */

			ppa_connect(dev, CONNECT_EPP_MAYBE);

			w_ctr(ppb, 0xe);
			if ((r_str(ppb) & 0x08) == 0x08)
				retv--;

			w_ctr(ppb, 0xc);
			if ((r_str(ppb) & 0x08) == 0x00)
				retv--;

			if (retv) {
				if (time_after(jiffies, dev->jstart + (1 * HZ))) {
					printk(KERN_ERR "ppa: Parallel port cable is unplugged.\n");
					ppa_fail(dev, DID_BUS_BUSY);
					return 0;
				} else {
					ppa_disconnect(dev);
					return 1;	/* Try again in a jiffy */
				}
			}
			cmd->SCp.phase++;
		}

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

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

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

	case 4:		/* Phase 4 - Setup scatter/gather buffers */
		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 = sg_virt(cmd->SCp.buffer);
		} 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++;

	case 5:		/* Phase 5 - Data transfer stage */
		w_ctr(ppb, 0x0c);
		if (!(r_str(ppb) & 0x80))
			return 1;

		retv = ppa_completion(cmd);
		if (retv == -1)
			return 0;
		if (retv == 0)
			return 1;
		cmd->SCp.phase++;

	case 6:		/* Phase 6 - Read status/message */
		cmd->result = DID_OK << 16;
		/* Check for data overrun */
		if (ppa_wait(dev) != (unsigned char) 0xf0) {
			ppa_fail(dev, DID_ERROR);
			return 0;
		}
		if (ppa_in(dev, &l, 1)) {	/* read status byte */
			/* Check for optional message byte */
			if (ppa_wait(dev) == (unsigned char) 0xf0)
				ppa_in(dev, &h, 1);
			cmd->result =
			    (DID_OK << 16) + (h << 8) + (l & STATUS_MASK);
		}
		return 0;	/* Finished */
		break;

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

static int ppa_queuecommand(struct scsi_cmnd *cmd,
		void (*done) (struct scsi_cmnd *))
{
	ppa_struct *dev = ppa_dev(cmd->device->host);

	if (dev->cur_cmd) {
		printk(KERN_ERR "PPA: bug in ppa_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 */

	schedule_delayed_work(&dev->ppa_tq, 0);

	ppa_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 ppa_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]);
		if (ip[2] > 1023)
			ip[2] = 1023;
	}
	return 0;
}

static int ppa_abort(struct scsi_cmnd *cmd)
{
	ppa_struct *dev = ppa_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 ppa_reset_pulse(unsigned int base)
{
	w_dtr(base, 0x40);
	w_ctr(base, 0x8);
	udelay(30);
	w_ctr(base, 0xc);
}

static int ppa_reset(struct scsi_cmnd *cmd)
{
	ppa_struct *dev = ppa_dev(cmd->device->host);

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

	ppa_connect(dev, CONNECT_NORMAL);
	ppa_reset_pulse(dev->base);
	mdelay(1);		/* device settle delay */
	ppa_disconnect(dev);
	mdelay(1);		/* device settle delay */
	return SUCCESS;
}

static int device_check(ppa_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 u8 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 = PPA_EPP_32;

second_pass:
		ppa_connect(dev, CONNECT_EPP_MAYBE);
		/* Select SCSI device */
		if (!ppa_select(dev, loop)) {
			ppa_disconnect(dev);
			continue;
		}
		printk(KERN_INFO "ppa: Found device at ID %i, Attempting to use %s\n",
		       loop, PPA_MODE_STRING[dev->mode]);

		/* Send SCSI command */
		status = 1;
		w_ctr(ppb, 0x0c);
		for (l = 0; (l < 6) && (status); l++)
			status = ppa_out(dev, cmd, 1);

		if (!status) {
			ppa_disconnect(dev);
			ppa_connect(dev, CONNECT_EPP_MAYBE);
			w_dtr(ppb, 0x40);
			w_ctr(ppb, 0x08);
			udelay(30);
			w_ctr(ppb, 0x0c);
			udelay(1000);
			ppa_disconnect(dev);
			udelay(1000);
			if (dev->mode == PPA_EPP_32) {
				dev->mode = old_mode;
				goto second_pass;
			}
			return -EIO;
		}
		w_ctr(ppb, 0x0c);
		k = 1000000;	/* 1 Second */
		do {
			l = r_str(ppb);
			k--;
			udelay(1);
		} while (!(l & 0x80) && (k));

		l &= 0xf0;

		if (l != 0xf0) {
			ppa_disconnect(dev);
			ppa_connect(dev, CONNECT_EPP_MAYBE);
			ppa_reset_pulse(ppb);
			udelay(1000);
			ppa_disconnect(dev);
			udelay(1000);
			if (dev->mode == PPA_EPP_32) {
				dev->mode = old_mode;
				goto second_pass;
			}
			return -EIO;
		}
		ppa_disconnect(dev);
		printk(KERN_INFO "ppa: Communication established with ID %i using %s\n",
		       loop, PPA_MODE_STRING[dev->mode]);
		ppa_connect(dev, CONNECT_EPP_MAYBE);
		ppa_reset_pulse(ppb);
		udelay(1000);
		ppa_disconnect(dev);
		udelay(1000);
		return 0;
	}
	return -ENODEV;
}

static int ppa_adjust_queue(struct scsi_device *device)
{
	blk_queue_bounce_limit(device->request_queue, BLK_BOUNCE_HIGH);
	return 0;
}

static struct scsi_host_template ppa_template = {
	.module			= THIS_MODULE,
	.proc_name		= "ppa",
	.proc_info		= ppa_proc_info,
	.name			= "Iomega VPI0 (ppa) interface",
	.queuecommand		= ppa_queuecommand,
	.eh_abort_handler	= ppa_abort,
	.eh_bus_reset_handler	= ppa_reset,
	.eh_host_reset_handler	= ppa_reset,
	.bios_param		= ppa_biosparam,
	.this_id		= -1,
	.sg_tablesize		= SG_ALL,
	.cmd_per_lun		= 1,
	.use_clustering		= ENABLE_CLUSTERING,
	.can_queue		= 1,
	.slave_alloc		= ppa_adjust_queue,
};

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

static LIST_HEAD(ppa_hosts);

static int __ppa_attach(struct parport *pb)
{
	struct Scsi_Host *host;
	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(waiting);
	DEFINE_WAIT(wait);
	ppa_struct *dev;
	int ports;
	int modes, ppb, ppb_hi;
	int err = -ENOMEM;

	dev = kzalloc(sizeof(ppa_struct), GFP_KERNEL);
	if (!dev)
		return -ENOMEM;
	dev->base = -1;
	dev->mode = PPA_AUTODETECT;
	dev->recon_tmo = PPA_RECON_TMO;
	init_waitqueue_head(&waiting);
	dev->dev = parport_register_device(pb, "ppa", NULL, ppa_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 (ppa_pb_claim(dev))
		schedule_timeout(3 * HZ);
	if (dev->wanted) {
		printk(KERN_ERR "ppa%d: failed to claim parport because "
				"a pardevice is owning the port for too long "
				"time!\n", pb->number);
		ppa_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;
	ppb_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 = PPA_NIBBLE;

	if (modes & PARPORT_MODE_TRISTATE)
		dev->mode = PPA_PS2;

	if (modes & PARPORT_MODE_ECP) {
		w_ecr(ppb_hi, 0x20);
		dev->mode = PPA_PS2;
	}
	if ((modes & PARPORT_MODE_EPP) && (modes & PARPORT_MODE_ECP))
		w_ecr(ppb_hi, 0x80);

	/* Done configuration */

	err = ppa_init(dev);
	ppa_pb_release(dev);

	if (err)
		goto out1;

	/* now the glue ... */
	if (dev->mode == PPA_NIBBLE || dev->mode == PPA_PS2)
		ports = 3;
	else
		ports = 8;

	INIT_DELAYED_WORK(&dev->ppa_tq, ppa_interrupt);

	err = -ENOMEM;
	host = scsi_host_alloc(&ppa_template, sizeof(ppa_struct *));
	if (!host)
		goto out1;
	host->io_port = pb->base;
	host->n_io_port = ports;
	host->dma_channel = -1;
	host->unique_id = pb->number;
	*(ppa_struct **)&host->hostdata = dev;
	dev->host = host;
	list_add_tail(&dev->list, &ppa_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 ppa_attach(struct parport *pb)
{
	__ppa_attach(pb);
}

static void ppa_detach(struct parport *pb)
{
	ppa_struct *dev;
	list_for_each_entry(dev, &ppa_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 ppa_driver = {
	.name	= "ppa",
	.attach	= ppa_attach,
	.detach	= ppa_detach,
};

static int __init ppa_driver_init(void)
{
	printk(KERN_INFO "ppa: Version %s\n", PPA_VERSION);
	return parport_register_driver(&ppa_driver);
}

static void __exit ppa_driver_exit(void)
{
	parport_unregister_driver(&ppa_driver);
}

module_init(ppa_driver_init);
module_exit(ppa_driver_exit);
MODULE_LICENSE("GPL");