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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/parport/ieee1284.c
downloadlinux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'drivers/parport/ieee1284.c')
-rw-r--r--drivers/parport/ieee1284.c819
1 files changed, 819 insertions, 0 deletions
diff --git a/drivers/parport/ieee1284.c b/drivers/parport/ieee1284.c
new file mode 100644
index 000000000000..694bae162fed
--- /dev/null
+++ b/drivers/parport/ieee1284.c
@@ -0,0 +1,819 @@
+/* $Id: parport_ieee1284.c,v 1.4 1997/10/19 21:37:21 philip Exp $
+ * 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/config.h>
+#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 one immediately. If it times out, it returns
+ * a value greater than zero. 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 (&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 (&timer) && !ret)
+ /* Timed out. */
+ ret = 1;
+
+ 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 zero 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 + (HZ + 24) / 25;
+ while (time_before (jiffies, deadline)) {
+ int ret;
+
+ 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, (HZ + 99) / 100)) < 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. */
+ __set_current_state (TASK_INTERRUPTIBLE);
+ schedule_timeout ((HZ+ 99) / 100);
+ }
+ }
+
+ 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 compability 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 (int which, void *handle, struct pt_regs *regs)
+{
+ 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);