lp.c

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/*
 * Generic parallel printer driver
 *
 * Copyright (C) 1992 by Jim Weigand and Linus Torvalds
 * Copyright (C) 1992,1993 by Michael K. Johnson
 * - Thanks much to Gunter Windau for pointing out to me where the error
 *   checking ought to be.
 * Copyright (C) 1993 by Nigel Gamble (added interrupt code)
 * Copyright (C) 1994 by Alan Cox (Modularised it)
 * LPCAREFUL, LPABORT, LPGETSTATUS added by Chris Metcalf, [e-mail]
 * Statistics and support for slow printers by Rob Janssen, [e-mail]
 * "lp=" command line parameters added by Grant Guenther, [e-mail]
 * lp_read (Status readback) support added by Carsten Gross,
 *                                             [e-mail]
 * Support for parport by Philip Blundell <[e-mail]>
 * Parport sharing hacking by Andrea Arcangeli
 * Fixed kernel_(to/from)_user memory copy to check for errors
 * 				by Riccardo Facchetti <[e-mail]>
 * 22-JAN-1998  Added support for devfs  Richard Gooch <[e-mail]>
 * Redesigned interrupt handling for handle printers with buggy handshake
 *				by Andrea Arcangeli, 11 May 1998
 * Full efficient handling of printer with buggy irq handshake (now I have
 * understood the meaning of the strange handshake). This is done sending new
 * characters if the interrupt is just happened, even if the printer say to
 * be still BUSY. This is needed at least with Epson Stylus Color. To enable
 * the new TRUST_IRQ mode read the `LP OPTIMIZATION' section below...
 * Fixed the irq on the rising edge of the strobe case.
 * Obsoleted the CAREFUL flag since a printer that doesn' t work with
 * CAREFUL will block a bit after in lp_check_status().
 *				Andrea Arcangeli, 15 Oct 1998
 * Obsoleted and removed all the lowlevel stuff implemented in the last
 * month to use the IEEE1284 functions (that handle the _new_ compatibilty
 * mode fine).
 */

/* This driver should, in theory, work with any parallel port that has an
 * appropriate low-level driver; all I/O is done through the parport
 * abstraction layer.
 *
 * If this driver is built into the kernel, you can configure it using the
 * kernel command-line.  For example:
 *
 *	lp=parport1,none,parport2	(bind lp0 to parport1, disable lp1 and
 *					 bind lp2 to parport2)
 *
 *	lp=auto				(assign lp devices to all ports that
 *				         have printers attached, as determined
 *					 by the IEEE-1284 autoprobe)
 * 
 *	lp=reset			(reset the printer during 
 *					 initialisation)
 *
 *	lp=off				(disable the printer driver entirely)
 *
 * If the driver is loaded as a module, similar functionality is available
 * using module parameters.  The equivalent of the above commands would be:
 *
 *	# insmod lp.o parport=1,none,2
 *
 *	# insmod lp.o parport=auto
 *
 *	# insmod lp.o reset=1
 */

/* COMPATIBILITY WITH OLD KERNELS
 *
 * Under Linux 2.0 and previous versions, lp devices were bound to ports at
 * particular I/O addresses, as follows:
 *
 *	lp0		0x3bc
 *	lp1		0x378
 *	lp2		0x278
 *
 * The new driver, by default, binds lp devices to parport devices as it
 * finds them.  This means that if you only have one port, it will be bound
 * to lp0 regardless of its I/O address.  If you need the old behaviour, you
 * can force it using the parameters described above.
 */

/*
 * The new interrupt handling code take care of the buggy handshake
 * of some HP and Epson printer:
 * ___
 * ACK    _______________    ___________
 *                       |__|
 * ____
 * BUSY   _________              _______
 *                 |____________|
 *
 * I discovered this using the printer scanner that you can find at:
 *
 *	ftp://e-mind.com/pub/linux/pscan/
 *
 *					11 May 98, Andrea Arcangeli
 *
 * My printer scanner run on an Epson Stylus Color show that such printer
 * generates the irq on the _rising_ edge of the STROBE. Now lp handle
 * this case fine too.
 *
 *					15 Oct 1998, Andrea Arcangeli
 *
 * The so called `buggy' handshake is really the well documented
 * compatibility mode IEEE1284 handshake. They changed the well known
 * Centronics handshake acking in the middle of busy expecting to not
 * break drivers or legacy application, while they broken linux lp
 * until I fixed it reverse engineering the protocol by hand some
 * month ago...
 *
 *                                     14 Dec 1998, Andrea Arcangeli
 *
 * Copyright (C) 2000 by Tim Waugh (added LPSETTIMEOUT ioctl)
 */

#include <linux/module.h>
#include <linux/init.h>

#include <linux/config.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/sched.h>
#include <linux/smp_lock.h>
#include <linux/devfs_fs_kernel.h>
#include <linux/slab.h>
#include <linux/fcntl.h>
#include <linux/delay.h>
#include <linux/poll.h>
#include <linux/console.h>

#include <linux/parport.h>
#undef LP_STATS
#include <linux/lp.h>

#include <asm/irq.h>
#include <asm/uaccess.h>
#include <asm/system.h>

/* if you have more than 8 printers, remember to increase LP_NO */
#define LP_NO 8

/* ROUND_UP macro from fs/select.c */
#define ROUND_UP(x,y) (((x)+(y)-1)/(y))

static devfs_handle_t devfs_handle = NULL;

struct lp_struct lp_table[LP_NO];

static unsigned int lp_count = 0;

#ifdef CONFIG_LP_CONSOLE
static struct parport *console_registered; // initially NULL
#endif /* CONFIG_LP_CONSOLE */

#undef LP_DEBUG

/* Bits used to manage claiming the parport device */
#define LP_PREEMPT_REQUEST 1
#define LP_PARPORT_CLAIMED 2

/* --- low-level port access ----------------------------------- */

#define r_dtr(x)	(parport_read_data(lp_table[(x)].dev->port))
#define r_str(x)	(parport_read_status(lp_table[(x)].dev->port))
#define w_ctr(x,y)	do { parport_write_control(lp_table[(x)].dev->port, (y)); } while (0)
#define w_dtr(x,y)	do { parport_write_data(lp_table[(x)].dev->port, (y)); } while (0)

/* Claim the parport or block trying unless we've already claimed it */
static void lp_claim_parport_or_block(struct lp_struct *this_lp)
{
	if (!test_and_set_bit(LP_PARPORT_CLAIMED, &this_lp->bits)) {
		parport_claim_or_block (this_lp->dev);
	}
}

/* Claim the parport or block trying unless we've already claimed it */
static void lp_release_parport(struct lp_struct *this_lp)
{
	if (test_and_clear_bit(LP_PARPORT_CLAIMED, &this_lp->bits)) {
		parport_release (this_lp->dev);
	}
}



static int lp_preempt(void *handle)
{
	struct lp_struct *this_lp = (struct lp_struct *)handle;
	set_bit(LP_PREEMPT_REQUEST, &this_lp->bits);
	return (1);
}


/* 
 * Try to negotiate to a new mode; if unsuccessful negotiate to
 * compatibility mode.  Return the mode we ended up in.
 */
static int lp_negotiate(struct parport * port, int mode)
{
	if (parport_negotiate (port, mode) != 0) {
		mode = IEEE1284_MODE_COMPAT;
		parport_negotiate (port, mode);
	}

	return (mode);
}

static int lp_reset(int minor)
{
	int retval;
	lp_claim_parport_or_block (&lp_table[minor]);
	w_ctr(minor, LP_PSELECP);
	udelay (LP_DELAY);
	w_ctr(minor, LP_PSELECP | LP_PINITP);
	retval = r_str(minor);
	lp_release_parport (&lp_table[minor]);
	return retval;
}

static void lp_error (int minor)
{
	int polling;

	if (LP_F(minor) & LP_ABORT)
		return;

	polling = lp_table[minor].dev->port->irq == PARPORT_IRQ_NONE;
	if (polling) lp_release_parport (&lp_table[minor]);
	interruptible_sleep_on_timeout (&lp_table[minor].waitq,
					LP_TIMEOUT_POLLED);
	if (polling) lp_claim_parport_or_block (&lp_table[minor]);
	else parport_yield_blocking (lp_table[minor].dev);
}

static int lp_check_status(int minor)
{
	int error = 0;
	unsigned int last = lp_table[minor].last_error;
	unsigned char status = r_str(minor);
	if ((status & LP_PERRORP) && !(LP_F(minor) & LP_CAREFUL))
		/* No error. */
		last = 0;
	else if ((status & LP_POUTPA)) {
		if (last != LP_POUTPA) {
			last = LP_POUTPA;
			printk(KERN_INFO "lp%d out of paper\n", minor);
		}
		error = -ENOSPC;
	} else if (!(status & LP_PSELECD)) {
		if (last != LP_PSELECD) {
			last = LP_PSELECD;
			printk(KERN_INFO "lp%d off-line\n", minor);
		}
		error = -EIO;
	} else if (!(status & LP_PERRORP)) {
		if (last != LP_PERRORP) {
			last = LP_PERRORP;
			printk(KERN_INFO "lp%d on fire\n", minor);
		}
		error = -EIO;
	} else {
		last = 0; /* Come here if LP_CAREFUL is set and no
                             errors are reported. */
	}

	lp_table[minor].last_error = last;

	if (last != 0)
		lp_error(minor);

	return error;
}

static int lp_wait_ready(int minor)
{
	int error = 0;

	/* If we're not in compatibility mode, we're ready now! */
	if (lp_table[minor].current_mode != IEEE1284_MODE_COMPAT) {
	  return (0);
	}

	do {
		error = lp_check_status (minor);
		if (error && (LP_F(minor) & LP_ABORT))
			break;
		if (signal_pending (current)) {
			error = -EINTR;
			break;
		}
	} while (error);
	return error;
}

static ssize_t lp_write(struct file * file, const char * buf,
		        size_t count, loff_t *ppos)
{
	unsigned int minor = MINOR(file->f_dentry->d_inode->i_rdev);
	struct parport *port = lp_table[minor].dev->port;
	char *kbuf = lp_table[minor].lp_buffer;
	ssize_t retv = 0;
	ssize_t written;
	size_t copy_size = count;

#ifdef LP_STATS
	if (jiffies-lp_table[minor].lastcall > LP_TIME(minor))
		lp_table[minor].runchars = 0;

	lp_table[minor].lastcall = jiffies;
#endif

	/* Need to copy the data from user-space. */
	if (copy_size > LP_BUFFER_SIZE)
		copy_size = LP_BUFFER_SIZE;

	if (copy_from_user (kbuf, buf, copy_size))
		return -EFAULT;

	if (down_interruptible (&lp_table[minor].port_mutex))
		return -EINTR;

 	/* Claim Parport or sleep until it becomes available
 	 */
	lp_claim_parport_or_block (&lp_table[minor]);
	/* Go to the proper mode. */
	lp_table[minor].current_mode = lp_negotiate (port, 
						     lp_table[minor].best_mode);

	parport_set_timeout (lp_table[minor].dev,
			     lp_table[minor].timeout);

	if ((retv = lp_wait_ready (minor)) == 0)
	do {
		/* Write the data. */
		written = parport_write (port, kbuf, copy_size);
		if (written >= 0) {
			copy_size -= written;
			count -= written;
			buf  += written;
			retv += written;
		}

		if (signal_pending (current)) {
			if (retv == 0)
				retv = -EINTR;

			break;
		}

		if (copy_size > 0) {
			/* incomplete write -> check error ! */
			int error;

			parport_negotiate (lp_table[minor].dev->port, 
					   IEEE1284_MODE_COMPAT);
			lp_table[minor].current_mode = IEEE1284_MODE_COMPAT;

			error = lp_wait_ready (minor);

			if (error) {
				if (retv == 0)
					retv = error;
				break;
			}

			parport_yield_blocking (lp_table[minor].dev);
			lp_table[minor].current_mode 
			  = lp_negotiate (port, 
					  lp_table[minor].best_mode);

		} else if (current->need_resched)
			schedule ();

		if (count) {
			copy_size = count;
			if (copy_size > LP_BUFFER_SIZE)
				copy_size = LP_BUFFER_SIZE;

			if (copy_from_user(kbuf, buf, copy_size)) {
				if (retv == 0)
					retv = -EFAULT;
				break;
			}
		}	
	} while (count > 0);

	if (test_and_clear_bit(LP_PREEMPT_REQUEST, 
			       &lp_table[minor].bits)) {
		printk(KERN_INFO "lp%d releasing parport\n", minor);
		parport_negotiate (lp_table[minor].dev->port, 
				   IEEE1284_MODE_COMPAT);
		lp_table[minor].current_mode = IEEE1284_MODE_COMPAT;
		lp_release_parport (&lp_table[minor]);
	}

	up (&lp_table[minor].port_mutex);

 	return retv;
}

#ifdef CONFIG_PARPORT_1284

/* Status readback conforming to ieee1284 */
static ssize_t lp_read(struct file * file, char * buf,
		       size_t count, loff_t *ppos)
{
	unsigned int minor=MINOR(file->f_dentry->d_inode->i_rdev);
	struct parport *port = lp_table[minor].dev->port;
	ssize_t retval = 0;
	char *kbuf = lp_table[minor].lp_buffer;

	if (count > LP_BUFFER_SIZE)
		count = LP_BUFFER_SIZE;

	if (down_interruptible (&lp_table[minor].port_mutex))
		return -EINTR;

	lp_claim_parport_or_block (&lp_table[minor]);
	retval = parport_read (port, kbuf, count);
	lp_release_parport (&lp_table[minor]);

	if (retval > 0 && copy_to_user (buf, kbuf, retval))
		retval = -EFAULT;

	up (&lp_table[minor].port_mutex);

	return retval;
}

#endif /* IEEE 1284 support */

static int lp_open(struct inode * inode, struct file * file)
{
	unsigned int minor = MINOR(inode->i_rdev);

	if (minor >= LP_NO)
		return -ENXIO;
	if ((LP_F(minor) & LP_EXIST) == 0)
		return -ENXIO;
	if (test_and_set_bit(LP_BUSY_BIT_POS, &LP_F(minor)))
		return -EBUSY;

	/* If ABORTOPEN is set and the printer is offline or out of paper,
	   we may still want to open it to perform ioctl()s.  Therefore we
	   have commandeered O_NONBLOCK, even though it is being used in
	   a non-standard manner.  This is strictly a Linux hack, and
	   should most likely only ever be used by the tunelp application. */
	if ((LP_F(minor) & LP_ABORTOPEN) && !(file->f_flags & O_NONBLOCK)) {
		int status;
		lp_claim_parport_or_block (&lp_table[minor]);
		status = r_str(minor);
		lp_release_parport (&lp_table[minor]);
		if (status & LP_POUTPA) {
			printk(KERN_INFO "lp%d out of paper\n", minor);
			LP_F(minor) &= ~LP_BUSY;
			return -ENOSPC;
		} else if (!(status & LP_PSELECD)) {
			printk(KERN_INFO "lp%d off-line\n", minor);
			LP_F(minor) &= ~LP_BUSY;
			return -EIO;
		} else if (!(status & LP_PERRORP)) {
			printk(KERN_ERR "lp%d printer error\n", minor);
			LP_F(minor) &= ~LP_BUSY;
			return -EIO;
		}
	}