Initial import

1 files changed, 817 insertions, 0 deletions

diff --git a/drivers/parport/ieee1284.c b/drivers/parport/ieee1284.c
new file mode 100644
index 000000000..f9fd4b33a
--- /dev/null
+++ b/drivers/parport/ieee1284.c
@@ -0,0 +1,817 @@
+/*
+ * IEEE-1284 implementation for parport.
+ *
+ * Authors: Phil Blundell <philb@gnu.org>
+ *          Carsten Gross <carsten@sol.wohnheim.uni-ulm.de>
+ *	    Jose Renau <renau@acm.org>
+ *          Tim Waugh <tim@cyberelk.demon.co.uk> (largely rewritten)
+ *
+ * This file is responsible for IEEE 1284 negotiation, and for handing
+ * read/write requests to low-level drivers.
+ *
+ * Any part of this program may be used in documents licensed under
+ * the GNU Free Documentation License, Version 1.1 or any later version
+ * published by the Free Software Foundation.
+ *
+ * Various hacks, Fred Barnes <frmb2@ukc.ac.uk>, 04/2000
+ */
+
+#include <linux/module.h>
+#include <linux/threads.h>
+#include <linux/parport.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/timer.h>
+#include <linux/sched.h>
+
+#undef 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
+
+/* Make parport_wait_peripheral wake up.
+ * It will be useful to call this from an interrupt handler. */
+static void parport_ieee1284_wakeup (struct parport *port)
+{
+	up (&port->physport->ieee1284.irq);
+}
+
+static struct parport *port_from_cookie[PARPORT_MAX];
+static void timeout_waiting_on_port (unsigned long cookie)
+{
+	parport_ieee1284_wakeup (port_from_cookie[cookie % PARPORT_MAX]);
+}
+
+/**
+ *	parport_wait_event - wait for an event on a parallel port
+ *	@port: port to wait on
+ *	@timeout: time to wait (in jiffies)
+ *
+ *	This function waits for up to @timeout jiffies for an
+ *	interrupt to occur on a parallel port.  If the port timeout is
+ *	set to zero, it returns immediately.
+ *
+ *	If an interrupt occurs before the timeout period elapses, this
+ *	function returns zero immediately.  If it times out, it returns
+ *	one.  An error code less than zero indicates an error (most
+ *	likely a pending signal), and the calling code should finish
+ *	what it's doing as soon as it can.
+ */
+
+int parport_wait_event (struct parport *port, signed long timeout)
+{
+	int ret;
+	struct timer_list timer;
+
+	if (!port->physport->cad->timeout)
+		/* Zero timeout is special, and we can't down() the
+		   semaphore. */
+		return 1;
+
+	init_timer_on_stack(&timer);
+	timer.expires = jiffies + timeout;
+	timer.function = timeout_waiting_on_port;
+	port_from_cookie[port->number % PARPORT_MAX] = port;
+	timer.data = port->number;
+
+	add_timer (&timer);
+	ret = down_interruptible (&port->physport->ieee1284.irq);
+	if (!del_timer_sync(&timer) && !ret)
+		/* Timed out. */
+		ret = 1;
+
+	destroy_timer_on_stack(&timer);
+
+	return ret;
+}
+
+/**
+ *	parport_poll_peripheral - poll status lines
+ *	@port: port to watch
+ *	@mask: status lines to watch
+ *	@result: desired values of chosen status lines
+ *	@usec: timeout
+ *
+ *	This function busy-waits until the masked status lines have
+ *	the desired values, or until the timeout period elapses.  The
+ *	@mask and @result parameters are bitmasks, with the bits
+ *	defined by the constants in parport.h: %PARPORT_STATUS_BUSY,
+ *	and so on.
+ *
+ *	This function does not call schedule(); instead it busy-waits
+ *	using udelay().  It currently has a resolution of 5usec.
+ *
+ *	If the status lines take on the desired values before the
+ *	timeout period elapses, parport_poll_peripheral() returns zero
+ *	immediately.  A return value greater than zero indicates
+ *	a timeout.  An error code (less than zero) indicates an error,
+ *	most likely a signal that arrived, and the caller should
+ *	finish what it is doing as soon as possible.
+*/
+
+int parport_poll_peripheral(struct parport *port,
+			    unsigned char mask,
+			    unsigned char result,
+			    int usec)
+{
+	/* Zero return code is success, >0 is timeout. */
+	int count = usec / 5 + 2;
+	int i;
+	unsigned char status;
+	for (i = 0; i < count; i++) {
+		status = parport_read_status (port);
+		if ((status & mask) == result)
+			return 0;
+		if (signal_pending (current))
+			return -EINTR;
+		if (need_resched())
+			break;
+		if (i >= 2)
+			udelay (5);
+	}
+
+	return 1;
+}
+
+/**
+ *	parport_wait_peripheral - wait for status lines to change in 35ms
+ *	@port: port to watch
+ *	@mask: status lines to watch
+ *	@result: desired values of chosen status lines
+ *
+ *	This function waits until the masked status lines have the
+ *	desired values, or until 35ms have elapsed (see IEEE 1284-1994
+ *	page 24 to 25 for why this value in particular is hardcoded).
+ *	The @mask and @result parameters are bitmasks, with the bits
+ *	defined by the constants in parport.h: %PARPORT_STATUS_BUSY,
+ *	and so on.
+ *
+ *	The port is polled quickly to start off with, in anticipation
+ *	of a fast response from the peripheral.  This fast polling
+ *	time is configurable (using /proc), and defaults to 500usec.
+ *	If the timeout for this port (see parport_set_timeout()) is
+ *	zero, the fast polling time is 35ms, and this function does
+ *	not call schedule().
+ *
+ *	If the timeout for this port is non-zero, after the fast
+ *	polling fails it uses parport_wait_event() to wait for up to
+ *	10ms, waking up if an interrupt occurs.
+ */
+
+int parport_wait_peripheral(struct parport *port,
+			    unsigned char mask, 
+			    unsigned char result)
+{
+	int ret;
+	int usec;
+	unsigned long deadline;
+	unsigned char status;
+
+	usec = port->physport->spintime; /* usecs of fast polling */
+	if (!port->physport->cad->timeout)
+		/* A zero timeout is "special": busy wait for the
+		   entire 35ms. */
+		usec = 35000;
+
+	/* Fast polling.
+	 *
+	 * This should be adjustable.
+	 * How about making a note (in the device structure) of how long
+	 * it takes, so we know for next time?
+	 */
+	ret = parport_poll_peripheral (port, mask, result, usec);
+	if (ret != 1)
+		return ret;
+
+	if (!port->physport->cad->timeout)
+		/* We may be in an interrupt handler, so we can't poll
+		 * slowly anyway. */
+		return 1;
+
+	/* 40ms of slow polling. */
+	deadline = jiffies + msecs_to_jiffies(40);
+	while (time_before (jiffies, deadline)) {
+		if (signal_pending (current))
+			return -EINTR;
+
+		/* Wait for 10ms (or until an interrupt occurs if
+		 * the handler is set) */
+		if ((ret = parport_wait_event (port, msecs_to_jiffies(10))) < 0)
+			return ret;
+
+		status = parport_read_status (port);
+		if ((status & mask) == result)
+			return 0;
+
+		if (!ret) {
+			/* parport_wait_event didn't time out, but the
+			 * peripheral wasn't actually ready either.
+			 * Wait for another 10ms. */
+			schedule_timeout_interruptible(msecs_to_jiffies(10));
+		}
+	}
+
+	return 1;
+}
+
+#ifdef CONFIG_PARPORT_1284
+/* Terminate a negotiated mode. */
+static void parport_ieee1284_terminate (struct parport *port)
+{
+	int r;
+	port = port->physport;
+
+	/* EPP terminates differently. */
+	switch (port->ieee1284.mode) {
+	case IEEE1284_MODE_EPP:
+	case IEEE1284_MODE_EPPSL:
+	case IEEE1284_MODE_EPPSWE:
+		/* Terminate from EPP mode. */
+
+		/* Event 68: Set nInit low */
+		parport_frob_control (port, PARPORT_CONTROL_INIT, 0);
+		udelay (50);
+
+		/* Event 69: Set nInit high, nSelectIn low */
+		parport_frob_control (port,
+				      PARPORT_CONTROL_SELECT
+				      | PARPORT_CONTROL_INIT,
+				      PARPORT_CONTROL_SELECT
+				      | PARPORT_CONTROL_INIT);
+		break;
+
+	case IEEE1284_MODE_ECP:
+	case IEEE1284_MODE_ECPRLE:
+	case IEEE1284_MODE_ECPSWE:
+		/* In ECP we can only terminate from fwd idle phase. */
+		if (port->ieee1284.phase != IEEE1284_PH_FWD_IDLE) {
+			/* 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 */
+			r = parport_wait_peripheral (port,
+						     PARPORT_STATUS_PAPEROUT,
+						     PARPORT_STATUS_PAPEROUT);
+			if (r)
+				DPRINTK (KERN_INFO "%s: Timeout at event 49\n",
+					 port->name);
+
+			parport_data_forward (port);
+			DPRINTK (KERN_DEBUG "%s: ECP direction: forward\n",
+				 port->name);
+			port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
+		}
+
+		/* fall-though.. */
+
+	default:
+		/* Terminate from all other modes. */
+
+		/* Event 22: Set nSelectIn low, nAutoFd high */
+		parport_frob_control (port,
+				      PARPORT_CONTROL_SELECT
+				      | PARPORT_CONTROL_AUTOFD,
+				      PARPORT_CONTROL_SELECT);
+
+		/* Event 24: nAck goes low */
+		r = parport_wait_peripheral (port, PARPORT_STATUS_ACK, 0);
+		if (r)
+			DPRINTK (KERN_INFO "%s: Timeout at event 24\n",
+				 port->name);
+
+		/* Event 25: Set nAutoFd low */
+		parport_frob_control (port,
+				      PARPORT_CONTROL_AUTOFD,
+				      PARPORT_CONTROL_AUTOFD);
+
+		/* Event 27: nAck goes high */
+		r = parport_wait_peripheral (port,
+					     PARPORT_STATUS_ACK, 
+					     PARPORT_STATUS_ACK);
+		if (r)
+			DPRINTK (KERN_INFO "%s: Timeout at event 27\n",
+				 port->name);
+
+		/* Event 29: Set nAutoFd high */
+		parport_frob_control (port, PARPORT_CONTROL_AUTOFD, 0);
+	}
+
+	port->ieee1284.mode = IEEE1284_MODE_COMPAT;
+	port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
+
+	DPRINTK (KERN_DEBUG "%s: In compatibility (forward idle) mode\n",
+		 port->name);
+}		
+#endif /* IEEE1284 support */
+
+/**
+ *	parport_negotiate - negotiate an IEEE 1284 mode
+ *	@port: port to use
+ *	@mode: mode to negotiate to
+ *
+ *	Use this to negotiate to a particular IEEE 1284 transfer mode.
+ *	The @mode parameter should be one of the constants in
+ *	parport.h starting %IEEE1284_MODE_xxx.
+ *
+ *	The return value is 0 if the peripheral has accepted the
+ *	negotiation to the mode specified, -1 if the peripheral is not
+ *	IEEE 1284 compliant (or not present), or 1 if the peripheral
+ *	has rejected the negotiation.
+ */
+
+int parport_negotiate (struct parport *port, int mode)
+{
+#ifndef CONFIG_PARPORT_1284
+	if (mode == IEEE1284_MODE_COMPAT)
+		return 0;
+	printk (KERN_ERR "parport: IEEE1284 not supported in this kernel\n");
+	return -1;
+#else
+	int m = mode & ~IEEE1284_ADDR;
+	int r;
+	unsigned char xflag;
+
+	port = port->physport;
+
+	/* Is there anything to do? */
+	if (port->ieee1284.mode == mode)
+		return 0;
+
+	/* Is the difference just an address-or-not bit? */
+	if ((port->ieee1284.mode & ~IEEE1284_ADDR) == (mode & ~IEEE1284_ADDR)){
+		port->ieee1284.mode = mode;
+		return 0;
+	}
+
+	/* Go to compatibility forward idle mode */
+	if (port->ieee1284.mode != IEEE1284_MODE_COMPAT)
+		parport_ieee1284_terminate (port);
+
+	if (mode == IEEE1284_MODE_COMPAT)
+		/* Compatibility mode: no negotiation. */
+		return 0; 
+
+	switch (mode) {
+	case IEEE1284_MODE_ECPSWE:
+		m = IEEE1284_MODE_ECP;
+		break;
+	case IEEE1284_MODE_EPPSL:
+	case IEEE1284_MODE_EPPSWE:
+		m = IEEE1284_MODE_EPP;
+		break;
+	case IEEE1284_MODE_BECP:
+		return -ENOSYS; /* FIXME (implement BECP) */
+	}
+
+	if (mode & IEEE1284_EXT_LINK)
+		m = 1<<7; /* request extensibility link */
+
+	port->ieee1284.phase = IEEE1284_PH_NEGOTIATION;
+
+	/* Start off with nStrobe and nAutoFd high, and nSelectIn low */
+	parport_frob_control (port,
+			      PARPORT_CONTROL_STROBE
+			      | PARPORT_CONTROL_AUTOFD
+			      | PARPORT_CONTROL_SELECT,
+			      PARPORT_CONTROL_SELECT);
+	udelay(1);
+
+	/* Event 0: Set data */
+	parport_data_forward (port);
+	parport_write_data (port, m);
+	udelay (400); /* Shouldn't need to wait this long. */
+
+	/* Event 1: Set nSelectIn high, nAutoFd low */
+	parport_frob_control (port,
+			      PARPORT_CONTROL_SELECT
+			      | PARPORT_CONTROL_AUTOFD,
+			      PARPORT_CONTROL_AUTOFD);
+
+	/* Event 2: PError, Select, nFault go high, nAck goes low */
+	if (parport_wait_peripheral (port,
+				     PARPORT_STATUS_ERROR
+				     | PARPORT_STATUS_SELECT
+				     | PARPORT_STATUS_PAPEROUT
+				     | PARPORT_STATUS_ACK,
+				     PARPORT_STATUS_ERROR
+				     | PARPORT_STATUS_SELECT
+				     | PARPORT_STATUS_PAPEROUT)) {
+		/* Timeout */
+		parport_frob_control (port,
+				      PARPORT_CONTROL_SELECT
+				      | PARPORT_CONTROL_AUTOFD,
+				      PARPORT_CONTROL_SELECT);
+		DPRINTK (KERN_DEBUG
+			 "%s: Peripheral not IEEE1284 compliant (0x%02X)\n",
+			 port->name, parport_read_status (port));
+		port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
+		return -1; /* Not IEEE1284 compliant */
+	}
+
+	/* Event 3: Set nStrobe low */
+	parport_frob_control (port,
+			      PARPORT_CONTROL_STROBE,
+			      PARPORT_CONTROL_STROBE);
+
+	/* Event 4: Set nStrobe and nAutoFd high */
+	udelay (5);
+	parport_frob_control (port,
+			      PARPORT_CONTROL_STROBE
+			      | PARPORT_CONTROL_AUTOFD,
+			      0);
+
+	/* Event 6: nAck goes high */
+	if (parport_wait_peripheral (port,
+				     PARPORT_STATUS_ACK,
+				     PARPORT_STATUS_ACK)) {
+		/* This shouldn't really happen with a compliant device. */
+		DPRINTK (KERN_DEBUG
+			 "%s: Mode 0x%02x not supported? (0x%02x)\n",
+			 port->name, mode, port->ops->read_status (port));
+		parport_ieee1284_terminate (port);
+		return 1;
+	}
+
+	xflag = parport_read_status (port) & PARPORT_STATUS_SELECT;
+
+	/* xflag should be high for all modes other than nibble (0). */
+	if (mode && !xflag) {
+		/* Mode not supported. */
+		DPRINTK (KERN_DEBUG "%s: Mode 0x%02x rejected by peripheral\n",
+			 port->name, mode);
+		parport_ieee1284_terminate (port);
+		return 1;
+	}
+
+	/* More to do if we've requested extensibility link. */
+	if (mode & IEEE1284_EXT_LINK) {
+		m = mode & 0x7f;
+		udelay (1);
+		parport_write_data (port, m);
+		udelay (1);
+
+		/* Event 51: Set nStrobe low */
+		parport_frob_control (port,
+				      PARPORT_CONTROL_STROBE,
+				      PARPORT_CONTROL_STROBE);
+
+		/* Event 52: nAck goes low */
+		if (parport_wait_peripheral (port, PARPORT_STATUS_ACK, 0)) {
+			/* This peripheral is _very_ slow. */
+			DPRINTK (KERN_DEBUG
+				 "%s: Event 52 didn't happen\n",
+				 port->name);
+			parport_ieee1284_terminate (port);
+			return 1;
+		}
+
+		/* Event 53: Set nStrobe high */
+		parport_frob_control (port,
+				      PARPORT_CONTROL_STROBE,
+				      0);
+
+		/* Event 55: nAck goes high */
+		if (parport_wait_peripheral (port,
+					     PARPORT_STATUS_ACK,
+					     PARPORT_STATUS_ACK)) {
+			/* This shouldn't really happen with a compliant
+			 * device. */
+			DPRINTK (KERN_DEBUG
+				 "%s: Mode 0x%02x not supported? (0x%02x)\n",
+				 port->name, mode,
+				 port->ops->read_status (port));
+			parport_ieee1284_terminate (port);
+			return 1;
+		}
+
+		/* Event 54: Peripheral sets XFlag to reflect support */
+		xflag = parport_read_status (port) & PARPORT_STATUS_SELECT;
+
+		/* xflag should be high. */
+		if (!xflag) {
+			/* Extended mode not supported. */
+			DPRINTK (KERN_DEBUG "%s: Extended mode 0x%02x not "
+				 "supported\n", port->name, mode);
+			parport_ieee1284_terminate (port);
+			return 1;
+		}
+
+		/* Any further setup is left to the caller. */
+	}
+
+	/* Mode is supported */
+	DPRINTK (KERN_DEBUG "%s: In mode 0x%02x\n", port->name, mode);
+	port->ieee1284.mode = mode;
+
+	/* But ECP is special */
+	if (!(mode & IEEE1284_EXT_LINK) && (m & IEEE1284_MODE_ECP)) {
+		port->ieee1284.phase = IEEE1284_PH_ECP_SETUP;
+
+		/* Event 30: Set nAutoFd low */
+		parport_frob_control (port,
+				      PARPORT_CONTROL_AUTOFD,
+				      PARPORT_CONTROL_AUTOFD);
+
+		/* Event 31: PError goes high. */
+		r = parport_wait_peripheral (port,
+					     PARPORT_STATUS_PAPEROUT,
+					     PARPORT_STATUS_PAPEROUT);
+		if (r) {
+			DPRINTK (KERN_INFO "%s: Timeout at event 31\n",
+				port->name);
+		}
+
+		port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
+		DPRINTK (KERN_DEBUG "%s: ECP direction: forward\n",
+			 port->name);
+	} else switch (mode) {
+	case IEEE1284_MODE_NIBBLE:
+	case IEEE1284_MODE_BYTE:
+		port->ieee1284.phase = IEEE1284_PH_REV_IDLE;
+		break;
+	default:
+		port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
+	}
+
+
+	return 0;
+#endif /* IEEE1284 support */
+}
+
+/* Acknowledge that the peripheral has data available.
+ * Events 18-20, in order to get from Reverse Idle phase
+ * to Host Busy Data Available.
+ * This will most likely be called from an interrupt.
+ * Returns zero if data was available.
+ */
+#ifdef CONFIG_PARPORT_1284
+static int parport_ieee1284_ack_data_avail (struct parport *port)
+{
+	if (parport_read_status (port) & PARPORT_STATUS_ERROR)
+		/* Event 18 didn't happen. */
+		return -1;
+
+	/* Event 20: nAutoFd goes high. */
+	port->ops->frob_control (port, PARPORT_CONTROL_AUTOFD, 0);
+	port->ieee1284.phase = IEEE1284_PH_HBUSY_DAVAIL;
+	return 0;
+}
+#endif /* IEEE1284 support */
+
+/* Handle an interrupt. */
+void parport_ieee1284_interrupt (void *handle)
+{
+	struct parport *port = handle;
+	parport_ieee1284_wakeup (port);
+
+#ifdef CONFIG_PARPORT_1284
+	if (port->ieee1284.phase == IEEE1284_PH_REV_IDLE) {
+		/* An interrupt in this phase means that data
+		 * is now available. */
+		DPRINTK (KERN_DEBUG "%s: Data available\n", port->name);
+		parport_ieee1284_ack_data_avail (port);
+	}
+#endif /* IEEE1284 support */
+}
+
+/**
+ *	parport_write - write a block of data to a parallel port
+ *	@port: port to write to
+ *	@buffer: data buffer (in kernel space)
+ *	@len: number of bytes of data to transfer
+ *
+ *	This will write up to @len bytes of @buffer to the port
+ *	specified, using the IEEE 1284 transfer mode most recently
+ *	negotiated to (using parport_negotiate()), as long as that
+ *	mode supports forward transfers (host to peripheral).
+ *
+ *	It is the caller's responsibility to ensure that the first
+ *	@len bytes of @buffer are valid.
+ *
+ *	This function returns the number of bytes transferred (if zero
+ *	or positive), or else an error code.
+ */
+
+ssize_t parport_write (struct parport *port, const void *buffer, size_t len)
+{
+#ifndef CONFIG_PARPORT_1284
+	return port->ops->compat_write_data (port, buffer, len, 0);
+#else
+	ssize_t retval;
+	int mode = port->ieee1284.mode;
+	int addr = mode & IEEE1284_ADDR;
+	size_t (*fn) (struct parport *, const void *, size_t, int);
+
+	/* Ignore the device-ID-request bit and the address bit. */
+	mode &= ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
+
+	/* Use the mode we're in. */
+	switch (mode) {
+	case IEEE1284_MODE_NIBBLE:
+	case IEEE1284_MODE_BYTE:
+		parport_negotiate (port, IEEE1284_MODE_COMPAT);
+	case IEEE1284_MODE_COMPAT:
+		DPRINTK (KERN_DEBUG "%s: Using compatibility mode\n",
+			 port->name);
+		fn = port->ops->compat_write_data;
+		break;
+
+	case IEEE1284_MODE_EPP:
+		DPRINTK (KERN_DEBUG "%s: Using EPP mode\n", port->name);
+		if (addr) {
+			fn = port->ops->epp_write_addr;
+		} else {
+			fn = port->ops->epp_write_data;
+		}
+		break;
+	case IEEE1284_MODE_EPPSWE:
+		DPRINTK (KERN_DEBUG "%s: Using software-emulated EPP mode\n",
+			port->name);
+		if (addr) {
+			fn = parport_ieee1284_epp_write_addr;
+		} else {
+			fn = parport_ieee1284_epp_write_data;
+		}
+		break;
+	case IEEE1284_MODE_ECP:
+	case IEEE1284_MODE_ECPRLE:
+		DPRINTK (KERN_DEBUG "%s: Using ECP mode\n", port->name);
+		if (addr) {
+			fn = port->ops->ecp_write_addr;
+		} else {
+			fn = port->ops->ecp_write_data;
+		}
+		break;
+
+	case IEEE1284_MODE_ECPSWE:
+		DPRINTK (KERN_DEBUG "%s: Using software-emulated ECP mode\n",
+			 port->name);
+		/* The caller has specified that it must be emulated,
+		 * even if we have ECP hardware! */
+		if (addr) {
+			fn = parport_ieee1284_ecp_write_addr;
+		} else {
+			fn = parport_ieee1284_ecp_write_data;
+		}
+		break;
+
+	default:
+		DPRINTK (KERN_DEBUG "%s: Unknown mode 0x%02x\n", port->name,
+			port->ieee1284.mode);
+		return -ENOSYS;
+	}
+
+	retval = (*fn) (port, buffer, len, 0);
+	DPRINTK (KERN_DEBUG "%s: wrote %d/%d bytes\n", port->name, retval, len);
+	return retval;
+#endif /* IEEE1284 support */
+}
+
+/**
+ *	parport_read - read a block of data from a parallel port
+ *	@port: port to read from
+ *	@buffer: data buffer (in kernel space)
+ *	@len: number of bytes of data to transfer
+ *
+ *	This will read up to @len bytes of @buffer to the port
+ *	specified, using the IEEE 1284 transfer mode most recently
+ *	negotiated to (using parport_negotiate()), as long as that
+ *	mode supports reverse transfers (peripheral to host).
+ *
+ *	It is the caller's responsibility to ensure that the first
+ *	@len bytes of @buffer are available to write to.
+ *
+ *	This function returns the number of bytes transferred (if zero
+ *	or positive), or else an error code.
+ */
+
+ssize_t parport_read (struct parport *port, void *buffer, size_t len)
+{
+#ifndef CONFIG_PARPORT_1284
+	printk (KERN_ERR "parport: IEEE1284 not supported in this kernel\n");
+	return -ENODEV;
+#else
+	int mode = port->physport->ieee1284.mode;
+	int addr = mode & IEEE1284_ADDR;
+	size_t (*fn) (struct parport *, void *, size_t, int);
+
+	/* Ignore the device-ID-request bit and the address bit. */
+	mode &= ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
+
+	/* Use the mode we're in. */
+	switch (mode) {
+	case IEEE1284_MODE_COMPAT:
+		/* if we can tri-state use BYTE mode instead of NIBBLE mode,
+		 * if that fails, revert to NIBBLE mode -- ought to store somewhere
+		 * the device's ability to do BYTE mode reverse transfers, so we don't
+		 * end up needlessly calling negotiate(BYTE) repeately..  (fb)
+		 */
+		if ((port->physport->modes & PARPORT_MODE_TRISTATE) &&
+		    !parport_negotiate (port, IEEE1284_MODE_BYTE)) {
+			/* got into BYTE mode OK */
+			DPRINTK (KERN_DEBUG "%s: Using byte mode\n", port->name);
+			fn = port->ops->byte_read_data;
+			break;
+		}
+		if (parport_negotiate (port, IEEE1284_MODE_NIBBLE)) {
+			return -EIO;
+		}
+		/* fall through to NIBBLE */
+	case IEEE1284_MODE_NIBBLE:
+		DPRINTK (KERN_DEBUG "%s: Using nibble mode\n", port->name);
+		fn = port->ops->nibble_read_data;
+		break;
+
+	case IEEE1284_MODE_BYTE:
+		DPRINTK (KERN_DEBUG "%s: Using byte mode\n", port->name);
+		fn = port->ops->byte_read_data;
+		break;
+
+	case IEEE1284_MODE_EPP:
+		DPRINTK (KERN_DEBUG "%s: Using EPP mode\n", port->name);
+		if (addr) {
+			fn = port->ops->epp_read_addr;
+		} else {
+			fn = port->ops->epp_read_data;
+		}
+		break;
+	case IEEE1284_MODE_EPPSWE:
+		DPRINTK (KERN_DEBUG "%s: Using software-emulated EPP mode\n",
+			port->name);
+		if (addr) {
+			fn = parport_ieee1284_epp_read_addr;
+		} else {
+			fn = parport_ieee1284_epp_read_data;
+		}
+		break;
+	case IEEE1284_MODE_ECP:
+	case IEEE1284_MODE_ECPRLE:
+		DPRINTK (KERN_DEBUG "%s: Using ECP mode\n", port->name);
+		fn = port->ops->ecp_read_data;
+		break;
+
+	case IEEE1284_MODE_ECPSWE:
+		DPRINTK (KERN_DEBUG "%s: Using software-emulated ECP mode\n",
+			 port->name);
+		fn = parport_ieee1284_ecp_read_data;
+		break;
+
+	default:
+		DPRINTK (KERN_DEBUG "%s: Unknown mode 0x%02x\n", port->name,
+			 port->physport->ieee1284.mode);
+		return -ENOSYS;
+	}
+
+	return (*fn) (port, buffer, len, 0);
+#endif /* IEEE1284 support */
+}
+
+/**
+ *	parport_set_timeout - set the inactivity timeout for a device
+ *	@dev: device on a port
+ *	@inactivity: inactivity timeout (in jiffies)
+ *
+ *	This sets the inactivity timeout for a particular device on a
+ *	port.  This affects functions like parport_wait_peripheral().
+ *	The special value 0 means not to call schedule() while dealing
+ *	with this device.
+ *
+ *	The return value is the previous inactivity timeout.
+ *
+ *	Any callers of parport_wait_event() for this device are woken
+ *	up.
+ */
+
+long parport_set_timeout (struct pardevice *dev, long inactivity)
+{
+	long int old = dev->timeout;
+
+	dev->timeout = inactivity;
+
+	if (dev->port->physport->cad == dev)
+		parport_ieee1284_wakeup (dev->port);
+
+	return old;
+}
+
+/* Exported symbols for modules. */
+
+EXPORT_SYMBOL(parport_negotiate);
+EXPORT_SYMBOL(parport_write);
+EXPORT_SYMBOL(parport_read);
+EXPORT_SYMBOL(parport_wait_peripheral);
+EXPORT_SYMBOL(parport_wait_event);
+EXPORT_SYMBOL(parport_set_timeout);
+EXPORT_SYMBOL(parport_ieee1284_interrupt);