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|
/*
* IEEE 1284.3 Parallel port daisy chain and multiplexor code
*
* Copyright (C) 1999, 2000 Tim Waugh <tim@cyberelk.demon.co.uk>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* ??-12-1998: Initial implementation.
* 31-01-1999: Make port-cloning transparent.
* 13-02-1999: Move DeviceID technique from parport_probe.
* 13-03-1999: Get DeviceID from non-IEEE 1284.3 devices too.
* 22-02-2000: Count devices that are actually detected.
*
* 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.
*/
#include <linux/module.h>
#include <linux/parport.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <asm/current.h>
#include <linux/uaccess.h>
#undef DEBUG
#ifdef DEBUG
#define DPRINTK(stuff...) printk(stuff)
#else
#define DPRINTK(stuff...)
#endif
static struct daisydev {
struct daisydev *next;
struct parport *port;
int daisy;
int devnum;
} *topology = NULL;
static DEFINE_SPINLOCK(topology_lock);
static int numdevs = 0;
/* Forward-declaration of lower-level functions. */
static int mux_present(struct parport *port);
static int num_mux_ports(struct parport *port);
static int select_port(struct parport *port);
static int assign_addrs(struct parport *port);
/* Add a device to the discovered topology. */
static void add_dev(int devnum, struct parport *port, int daisy)
{
struct daisydev *newdev, **p;
newdev = kmalloc(sizeof(struct daisydev), GFP_KERNEL);
if (newdev) {
newdev->port = port;
newdev->daisy = daisy;
newdev->devnum = devnum;
spin_lock(&topology_lock);
for (p = &topology; *p && (*p)->devnum<devnum; p = &(*p)->next)
;
newdev->next = *p;
*p = newdev;
spin_unlock(&topology_lock);
}
}
/* Clone a parport (actually, make an alias). */
static struct parport *clone_parport(struct parport *real, int muxport)
{
struct parport *extra = parport_register_port(real->base,
real->irq,
real->dma,
real->ops);
if (extra) {
extra->portnum = real->portnum;
extra->physport = real;
extra->muxport = muxport;
real->slaves[muxport-1] = extra;
}
return extra;
}
/* Discover the IEEE1284.3 topology on a port -- muxes and daisy chains.
* Return value is number of devices actually detected. */
int parport_daisy_init(struct parport *port)
{
int detected = 0;
char *deviceid;
static const char *th[] = { /*0*/"th", "st", "nd", "rd", "th" };
int num_ports;
int i;
int last_try = 0;
again:
/* Because this is called before any other devices exist,
* we don't have to claim exclusive access. */
/* If mux present on normal port, need to create new
* parports for each extra port. */
if (port->muxport < 0 && mux_present(port) &&
/* don't be fooled: a mux must have 2 or 4 ports. */
((num_ports = num_mux_ports(port)) == 2 || num_ports == 4)) {
/* Leave original as port zero. */
port->muxport = 0;
printk(KERN_INFO
"%s: 1st (default) port of %d-way multiplexor\n",
port->name, num_ports);
for (i = 1; i < num_ports; i++) {
/* Clone the port. */
struct parport *extra = clone_parport(port, i);
if (!extra) {
if (signal_pending(current))
break;
schedule();
continue;
}
printk(KERN_INFO
"%s: %d%s port of %d-way multiplexor on %s\n",
extra->name, i + 1, th[i + 1], num_ports,
port->name);
/* Analyse that port too. We won't recurse
forever because of the 'port->muxport < 0'
test above. */
parport_daisy_init(extra);
}
}
if (port->muxport >= 0)
select_port(port);
parport_daisy_deselect_all(port);
detected += assign_addrs(port);
/* Count the potential legacy device at the end. */
add_dev(numdevs++, port, -1);
/* Find out the legacy device's IEEE 1284 device ID. */
deviceid = kmalloc(1024, GFP_KERNEL);
if (deviceid) {
if (parport_device_id(numdevs - 1, deviceid, 1024) > 2)
detected++;
kfree(deviceid);
}
if (!detected && !last_try) {
/* No devices were detected. Perhaps they are in some
funny state; let's try to reset them and see if
they wake up. */
parport_daisy_fini(port);
parport_write_control(port, PARPORT_CONTROL_SELECT);
udelay(50);
parport_write_control(port,
PARPORT_CONTROL_SELECT |
PARPORT_CONTROL_INIT);
udelay(50);
last_try = 1;
goto again;
}
return detected;
}
/* Forget about devices on a physical port. */
void parport_daisy_fini(struct parport *port)
{
struct daisydev **p;
spin_lock(&topology_lock);
p = &topology;
while (*p) {
struct daisydev *dev = *p;
if (dev->port != port) {
p = &dev->next;
continue;
}
*p = dev->next;
kfree(dev);
}
/* Gaps in the numbering could be handled better. How should
someone enumerate through all IEEE1284.3 devices in the
topology?. */
if (!topology) numdevs = 0;
spin_unlock(&topology_lock);
return;
}
/**
* parport_open - find a device by canonical device number
* @devnum: canonical device number
* @name: name to associate with the device
*
* This function is similar to parport_register_device(), except
* that it locates a device by its number rather than by the port
* it is attached to.
*
* All parameters except for @devnum are the same as for
* parport_register_device(). The return value is the same as
* for parport_register_device().
**/
struct pardevice *parport_open(int devnum, const char *name)
{
struct daisydev *p = topology;
struct parport *port;
struct pardevice *dev;
int daisy;
spin_lock(&topology_lock);
while (p && p->devnum != devnum)
p = p->next;
if (!p) {
spin_unlock(&topology_lock);
return NULL;
}
daisy = p->daisy;
port = parport_get_port(p->port);
spin_unlock(&topology_lock);
dev = parport_register_device(port, name, NULL, NULL, NULL, 0, NULL);
parport_put_port(port);
if (!dev)
return NULL;
dev->daisy = daisy;
/* Check that there really is a device to select. */
if (daisy >= 0) {
int selected;
parport_claim_or_block(dev);
selected = port->daisy;
parport_release(dev);
if (selected != daisy) {
/* No corresponding device. */
parport_unregister_device(dev);
return NULL;
}
}
return dev;
}
/**
* parport_close - close a device opened with parport_open()
* @dev: device to close
*
* This is to parport_open() as parport_unregister_device() is to
* parport_register_device().
**/
void parport_close(struct pardevice *dev)
{
parport_unregister_device(dev);
}
/* Send a daisy-chain-style CPP command packet. */
static int cpp_daisy(struct parport *port, int cmd)
{
unsigned char s;
parport_data_forward(port);
parport_write_data(port, 0xaa); udelay(2);
parport_write_data(port, 0x55); udelay(2);
parport_write_data(port, 0x00); udelay(2);
parport_write_data(port, 0xff); udelay(2);
s = parport_read_status(port) & (PARPORT_STATUS_BUSY
| PARPORT_STATUS_PAPEROUT
| PARPORT_STATUS_SELECT
| PARPORT_STATUS_ERROR);
if (
|