ieee1284_ops.c

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/* IEEE-1284 operations for parport.
 *
 * This file is for generic IEEE 1284 operations.  The idea is that
 * they are used by the low-level drivers.  If they have a special way
 * of doing something, they can provide their own routines (and put
 * the function pointers in port->ops); if not, they can just use these
 * as a fallback.
 *
 * Note: Make no assumptions about hardware or architecture in this file!
 *
 * Author: Tim Waugh <[e-mail]>
 * Fixed AUTOFD polarity in ecp_forward_to_reverse().  Fred Barnes, 1999
 */


#include <linux/config.h>
#include <linux/parport.h>
#include <linux/delay.h>
#include <asm/uaccess.h>

#define DEBUG /* undef me for production */

#ifdef CONFIG_LP_CONSOLE
#undef DEBUG /* Don't want a garbled console */
#endif

#ifdef DEBUG
#define DPRINTK(stuff...) printk (stuff)
#else
#define DPRINTK(stuff...)
#endif

/***                                *
 * One-way data transfer functions. *
 *                                ***/

/* Compatibility mode. */
size_t parport_ieee1284_write_compat (struct parport *port,
				      const void *buffer, size_t len,
				      int flags)
{
	int no_irq = 1;
	ssize_t count = 0;
	const unsigned char *addr = buffer;
	unsigned char byte;
	struct pardevice *dev = port->physport->cad;
	unsigned char ctl = (PARPORT_CONTROL_SELECT
			     | PARPORT_CONTROL_INIT);

	if (port->irq != PARPORT_IRQ_NONE) {
		parport_enable_irq (port);
		no_irq = 0;

		/* Clear out previous irqs. */
		while (!down_trylock (&port->physport->ieee1284.irq));
	}

	port->physport->ieee1284.phase = IEEE1284_PH_FWD_DATA;
	parport_write_control (port, ctl);
	parport_data_forward (port);
	while (count < len) {
		long expire = jiffies + dev->timeout;
		long wait = (HZ + 99) / 100;
		unsigned char mask = (PARPORT_STATUS_ERROR
				      | PARPORT_STATUS_BUSY);
		unsigned char val = (PARPORT_STATUS_ERROR
				     | PARPORT_STATUS_BUSY);

		/* Wait until the peripheral's ready */
		do {
			/* Is the peripheral ready yet? */
			if (!parport_wait_peripheral (port, mask, val))
				/* Skip the loop */
				goto ready;

			/* Is the peripheral upset? */
			if ((parport_read_status (port) &
			     (PARPORT_STATUS_PAPEROUT |
			      PARPORT_STATUS_SELECT |
			      PARPORT_STATUS_ERROR))
			    != (PARPORT_STATUS_SELECT |
				PARPORT_STATUS_ERROR))
				/* If nFault is asserted (i.e. no
				 * error) and PAPEROUT and SELECT are
				 * just red herrings, give the driver
				 * a chance to check it's happy with
				 * that before continuing. */
				goto stop;

			/* Have we run out of time? */
			if (!time_before (jiffies, expire))
				break;

			/* Yield the port for a while.  If this is the
                           first time around the loop, don't let go of
                           the port.  This way, we find out if we have
                           our interrupt handler called. */
			if (count && no_irq) {
				parport_release (dev);
				__set_current_state (TASK_INTERRUPTIBLE);
				schedule_timeout (wait);
				parport_claim_or_block (dev);
			}
			else
				/* We must have the device claimed here */
				parport_wait_event (port, wait);

			/* Is there a signal pending? */
			if (signal_pending (current))
				break;

			/* Wait longer next time. */
			wait *= 2;
		} while (time_before (jiffies, expire));

		if (signal_pending (current))
			break;

		DPRINTK (KERN_DEBUG "%s: Timed out\n", port->name);
		break;

	ready:
		/* Write the character to the data lines. */
		byte = *addr++;
		parport_write_data (port, byte);
		udelay (1);

		/* Pulse strobe. */
		parport_write_control (port, ctl | PARPORT_CONTROL_STROBE);
		udelay (1); /* strobe */

		parport_write_control (port, ctl);
		udelay (1); /* hold */

		/* Assume the peripheral received it. */
		count++;

                /* Let another process run if it needs to. */
		if (time_before (jiffies, expire))
			if (!parport_yield_blocking (dev)
			    && current->need_resched)
				schedule ();
	}
 stop:
	port->physport->ieee1284.phase = IEEE1284_PH_FWD_IDLE;

	return count;
}

/* Nibble mode. */
size_t parport_ieee1284_read_nibble (struct parport *port, 
				     void *buffer, size_t len,
				     int flags)
{
#ifndef CONFIG_PARPORT_1284
	return 0;
#else
	unsigned char *buf = buffer;
	int i;
	unsigned char byte = 0;

	len *= 2; /* in nibbles */
	for (i=0; i < len; i++) {
		unsigned char nibble;

		/* Does the error line indicate end of data? */
		if (((i & 1) == 0) &&
		    (parport_read_status(port) & PARPORT_STATUS_ERROR)) {
			port->physport->ieee1284.phase = IEEE1284_PH_HBUSY_DNA;
			DPRINTK (KERN_DEBUG
				"%s: No more nibble data (%d bytes)\n",
				port->name, i/2);

			/* Go to reverse idle phase. */
			parport_frob_control (port,
					      PARPORT_CONTROL_AUTOFD,
					      PARPORT_CONTROL_AUTOFD);
			port->physport->ieee1284.phase = IEEE1284_PH_REV_IDLE;
			break;
		}

		/* Event 7: Set nAutoFd low. */
		parport_frob_control (port,
				      PARPORT_CONTROL_AUTOFD,
				      PARPORT_CONTROL_AUTOFD);

		/* Event 9: nAck goes low. */
		port->ieee1284.phase = IEEE1284_PH_REV_DATA;
		if (parport_wait_peripheral (port,
					     PARPORT_STATUS_ACK, 0)) {
			/* Timeout -- no more data? */
			DPRINTK (KERN_DEBUG
				 "%s: Nibble timeout at event 9 (%d bytes)\n",
				 port->name, i/2);
			break;
		}


		/* Read a nibble. */
		nibble = parport_read_status (port) >> 3;
		nibble &= ~8;
		if ((nibble & 0x10) == 0)
			nibble |= 8;
		nibble &= 0xf;

		/* Event 10: Set nAutoFd high. */
		parport_frob_control (port, PARPORT_CONTROL_AUTOFD, 0);

		/* Event 11: nAck goes high. */
		if (parport_wait_peripheral (port,
					     PARPORT_STATUS_ACK,
					     PARPORT_STATUS_ACK)) {
			/* Timeout -- no more data? */
			DPRINTK (KERN_DEBUG
				 "%s: Nibble timeout at event 11\n",
				 port->name);
			break;
		}

		if (i & 1) {
			/* Second nibble */
			byte |= nibble << 4;
			*buf++ = byte;
		} else 
			byte = nibble;
	}

	i /= 2; /* i is now in bytes */

	if (i == len) {
		/* Read the last nibble without checking data avail. */
		port = port->physport;
		if (parport_read_status (port) & PARPORT_STATUS_ERROR)
			port->ieee1284.phase = IEEE1284_PH_HBUSY_DNA;
		else
			port->ieee1284.phase = IEEE1284_PH_HBUSY_DAVAIL;
	}

	return i;
#endif /* IEEE1284 support */
}

/* Byte mode. */
size_t parport_ieee1284_read_byte (struct parport *port,
				   void *buffer, size_t len,
				   int flags)
{
#ifndef CONFIG_PARPORT_1284
	return 0;
#else
	unsigned char *buf = buffer;
	ssize_t count = 0;

	for (count = 0; count < len; count++) {
		unsigned char byte;

		/* Data available? */
		if (parport_read_status (port) & PARPORT_STATUS_ERROR) {
			port->physport->ieee1284.phase = IEEE1284_PH_HBUSY_DNA;
			DPRINTK (KERN_DEBUG
				 "%s: No more byte data (%Zd bytes)\n",
				 port->name, count);

			/* Go to reverse idle phase. */
			parport_frob_control (port,
					      PARPORT_CONTROL_AUTOFD,
					      PARPORT_CONTROL_AUTOFD);
			port->physport->ieee1284.phase = IEEE1284_PH_REV_IDLE;
			break;
		}

		/* Event 14: Place data bus in high impedance state. */
		parport_data_reverse (port);

		/* Event 7: Set nAutoFd low. */
		parport_frob_control (port,
				      PARPORT_CONTROL_AUTOFD,
				      PARPORT_CONTROL_AUTOFD);

		/* Event 9: nAck goes low. */
		port->physport->ieee1284.phase = IEEE1284_PH_REV_DATA;
		if (parport_wait_peripheral (port,
					     PARPORT_STATUS_ACK,
					     0)) {
			/* Timeout -- no more data? */
			parport_frob_control (port, PARPORT_CONTROL_AUTOFD,
						 0);
			DPRINTK (KERN_DEBUG "%s: Byte timeout at event 9\n",
				 port->name);
			break;
		}

		byte = parport_read_data (port);
		*buf++ = byte;

		/* Event 10: Set nAutoFd high */
		parport_frob_control (port, PARPORT_CONTROL_AUTOFD, 0);

		/* Event 11: nAck goes high. */
		if (parport_wait_peripheral (port,
					     PARPORT_STATUS_ACK,
					     PARPORT_STATUS_ACK)) {
			/* Timeout -- no more data? */
			DPRINTK (KERN_DEBUG "%s: Byte timeout at event 11\n",
				 port->name);
			break;
		}

		/* Event 16: Set nStrobe low. */
		parport_frob_control (port,
				      PARPORT_CONTROL_STROBE,
				      PARPORT_CONTROL_STROBE);
		udelay (5);

		/* Event 17: Set nStrobe high. */
		parport_frob_control (port, PARPORT_CONTROL_STROBE, 0);
	}

	if (count == len) {
		/* Read the last byte without checking data avail. */
		port = port->physport;
		if (parport_read_status (port) & PARPORT_STATUS_ERROR)
			port->ieee1284.phase = IEEE1284_PH_HBUSY_DNA;
		else
			port->ieee1284.phase = IEEE1284_PH_HBUSY_DAVAIL;
	}

	return count;
#endif /* IEEE1284 support */
}

/***              *
 * ECP Functions. *
 *              ***/

#ifdef CONFIG_PARPORT_1284

static inline
int ecp_forward_to_reverse (struct parport *port)
{
	int retval;

	/* Event 38: Set nAutoFd low */
	parport_frob_control (port,
			      PARPORT_CONTROL_AUTOFD,
			      PARPORT_CONTROL_AUTOFD);
	parport_data_reverse (port);
	udelay (5);

	/* Event 39: Set nInit low to initiate bus reversal */
	parport_frob_control (port,
			      PARPORT_CONTROL_INIT,
			      0);

	/* Event 40: PError goes low */
	retval = parport_wait_peripheral (port,
					  PARPORT_STATUS_PAPEROUT, 0);

	if (!retval) {
		DPRINTK (KERN_DEBUG "%s: ECP direction: reverse\n",
			 port->name);
		port->ieee1284.phase = IEEE1284_PH_REV_IDLE;
	}

	return retval;
}

static inline
int ecp_reverse_to_forward (struct parport *port)
{
	int retval;

	/* Event 47: Set nInit high */
	parport_frob_control (port,
			      PARPORT_CONTROL_INIT
			      | PARPORT_CONTROL_AUTOFD,
			      PARPORT_CONTROL_INIT
			      | PARPORT_CONTROL_AUTOFD);

	/* Event 49: PError goes high */
	retval = parport_wait_peripheral (port,
					  PARPORT_STATUS_PAPEROUT,
					  PARPORT_STATUS_PAPEROUT);

	if (!retval) {
		parport_data_forward (port);
		DPRINTK (KERN_DEBUG "%s: ECP direction: forward\n",
			 port->name);
		port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
	}

	return retval;
}

#endif /* IEEE1284 support */

/* ECP mode, forward channel, data. */
size_t parport_ieee1284_ecp_write_data (struct parport *port,
					const void *buffer, size_t len,
					int flags)
{
#ifndef CONFIG_PARPORT_1284
	return 0;
#else
	const unsigned char *buf = buffer;
	size_t written;
	int retry;

	port = port->physport;

	if (port->ieee1284.phase != IEEE1284_PH_FWD_IDLE)
		if (ecp_reverse_to_forward (port))
			return 0;

	port->ieee1284.phase = IEEE1284_PH_FWD_DATA;

	/* HostAck high (data, not command) */
	parport_frob_control (port,
			      PARPORT_CONTROL_AUTOFD
			      | PARPORT_CONTROL_STROBE
			      | PARPORT_CONTROL_INIT,
			      PARPORT_CONTROL_INIT);
	for (written = 0; written < len; written++, buf++) {
		long expire = jiffies + port->cad->timeout;
		unsigned char byte;

		byte = *buf;
	try_again:
		parport_write_data (port, byte);
		parport_frob_control (port, PARPORT_CONTROL_STROBE,
				      PARPORT_CONTROL_STROBE);
		udelay (5);
		for (retry = 0; retry < 100; retry++) {
			if (!parport_wait_peripheral (port,
						      PARPORT_STATUS_BUSY, 0))
				goto success;

			if (signal_pending (current)) {
				parport_frob_control (port,