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|
/*
* 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/signal.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 void timeout_waiting_on_port (struct timer_list *t)
{
struct parport *port = from_timer(port, t, timer);
parport_ieee1284_wakeup (port);
}
/**
* 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;
if (!port->physport->cad->timeout)
/* Zero timeout is special, and we can't down() the
semaphore. */
return 1;
timer_setup(&port->timer, timeout_waiting_on_port, 0);
mod_timer(&port->timer, jiffies + timeout);
ret = down_interruptible (&port->physport->ieee1284.irq);
if (!del_timer_sync(&port->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 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 =<
|