482 lines
12 KiB
C
482 lines
12 KiB
C
/*
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* IEEE 1284.3 Parallel port daisy chain and multiplexor code
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*
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* Copyright (C) 1999, 2000 Tim Waugh <tim@cyberelk.demon.co.uk>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* ??-12-1998: Initial implementation.
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* 31-01-1999: Make port-cloning transparent.
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* 13-02-1999: Move DeviceID technique from parport_probe.
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* 13-03-1999: Get DeviceID from non-IEEE 1284.3 devices too.
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* 22-02-2000: Count devices that are actually detected.
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*
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* Any part of this program may be used in documents licensed under
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* the GNU Free Documentation License, Version 1.1 or any later version
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/parport.h>
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#include <linux/delay.h>
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#include <linux/sched.h>
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#include <asm/current.h>
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#include <asm/uaccess.h>
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#undef DEBUG
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#ifdef DEBUG
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#define DPRINTK(stuff...) printk(stuff)
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#else
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#define DPRINTK(stuff...)
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#endif
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static struct daisydev {
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struct daisydev *next;
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struct parport *port;
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int daisy;
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int devnum;
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} *topology = NULL;
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static DEFINE_SPINLOCK(topology_lock);
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static int numdevs = 0;
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/* Forward-declaration of lower-level functions. */
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static int mux_present(struct parport *port);
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static int num_mux_ports(struct parport *port);
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static int select_port(struct parport *port);
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static int assign_addrs(struct parport *port);
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/* Add a device to the discovered topology. */
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static void add_dev(int devnum, struct parport *port, int daisy)
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{
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struct daisydev *newdev, **p;
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newdev = kmalloc(sizeof(struct daisydev), GFP_KERNEL);
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if (newdev) {
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newdev->port = port;
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newdev->daisy = daisy;
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newdev->devnum = devnum;
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spin_lock(&topology_lock);
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for (p = &topology; *p && (*p)->devnum<devnum; p = &(*p)->next)
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;
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newdev->next = *p;
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*p = newdev;
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spin_unlock(&topology_lock);
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}
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}
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/* Clone a parport (actually, make an alias). */
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static struct parport *clone_parport(struct parport *real, int muxport)
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{
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struct parport *extra = parport_register_port(real->base,
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real->irq,
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real->dma,
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real->ops);
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if (extra) {
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extra->portnum = real->portnum;
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extra->physport = real;
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extra->muxport = muxport;
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real->slaves[muxport-1] = extra;
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}
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return extra;
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}
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/* Discover the IEEE1284.3 topology on a port -- muxes and daisy chains.
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* Return value is number of devices actually detected. */
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int parport_daisy_init(struct parport *port)
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{
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int detected = 0;
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char *deviceid;
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static const char *th[] = { /*0*/"th", "st", "nd", "rd", "th" };
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int num_ports;
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int i;
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int last_try = 0;
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again:
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/* Because this is called before any other devices exist,
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* we don't have to claim exclusive access. */
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/* If mux present on normal port, need to create new
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* parports for each extra port. */
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if (port->muxport < 0 && mux_present(port) &&
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/* don't be fooled: a mux must have 2 or 4 ports. */
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((num_ports = num_mux_ports(port)) == 2 || num_ports == 4)) {
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/* Leave original as port zero. */
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port->muxport = 0;
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printk(KERN_INFO
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"%s: 1st (default) port of %d-way multiplexor\n",
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port->name, num_ports);
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for (i = 1; i < num_ports; i++) {
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/* Clone the port. */
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struct parport *extra = clone_parport(port, i);
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if (!extra) {
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if (signal_pending(current))
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break;
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schedule();
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continue;
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}
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printk(KERN_INFO
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"%s: %d%s port of %d-way multiplexor on %s\n",
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extra->name, i + 1, th[i + 1], num_ports,
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port->name);
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/* Analyse that port too. We won't recurse
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forever because of the 'port->muxport < 0'
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test above. */
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parport_daisy_init(extra);
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}
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}
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if (port->muxport >= 0)
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select_port(port);
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parport_daisy_deselect_all(port);
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detected += assign_addrs(port);
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/* Count the potential legacy device at the end. */
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add_dev(numdevs++, port, -1);
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/* Find out the legacy device's IEEE 1284 device ID. */
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deviceid = kmalloc(1024, GFP_KERNEL);
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if (deviceid) {
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if (parport_device_id(numdevs - 1, deviceid, 1024) > 2)
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detected++;
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kfree(deviceid);
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}
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if (!detected && !last_try) {
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/* No devices were detected. Perhaps they are in some
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funny state; let's try to reset them and see if
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they wake up. */
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parport_daisy_fini(port);
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parport_write_control(port, PARPORT_CONTROL_SELECT);
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udelay(50);
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parport_write_control(port,
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PARPORT_CONTROL_SELECT |
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PARPORT_CONTROL_INIT);
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udelay(50);
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last_try = 1;
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goto again;
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}
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return detected;
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}
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/* Forget about devices on a physical port. */
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void parport_daisy_fini(struct parport *port)
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{
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struct daisydev **p;
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spin_lock(&topology_lock);
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p = &topology;
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while (*p) {
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struct daisydev *dev = *p;
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if (dev->port != port) {
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p = &dev->next;
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continue;
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}
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*p = dev->next;
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kfree(dev);
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}
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/* Gaps in the numbering could be handled better. How should
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someone enumerate through all IEEE1284.3 devices in the
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topology?. */
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if (!topology) numdevs = 0;
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spin_unlock(&topology_lock);
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return;
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}
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/**
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* parport_open - find a device by canonical device number
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* @devnum: canonical device number
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* @name: name to associate with the device
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*
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* This function is similar to parport_register_device(), except
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* that it locates a device by its number rather than by the port
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* it is attached to.
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*
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* All parameters except for @devnum are the same as for
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* parport_register_device(). The return value is the same as
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* for parport_register_device().
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**/
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struct pardevice *parport_open(int devnum, const char *name)
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{
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struct daisydev *p = topology;
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struct parport *port;
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struct pardevice *dev;
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int daisy;
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spin_lock(&topology_lock);
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while (p && p->devnum != devnum)
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p = p->next;
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if (!p) {
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spin_unlock(&topology_lock);
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return NULL;
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}
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daisy = p->daisy;
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port = parport_get_port(p->port);
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spin_unlock(&topology_lock);
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dev = parport_register_device(port, name, NULL, NULL, NULL, 0, NULL);
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parport_put_port(port);
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if (!dev)
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return NULL;
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dev->daisy = daisy;
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/* Check that there really is a device to select. */
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if (daisy >= 0) {
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int selected;
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parport_claim_or_block(dev);
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selected = port->daisy;
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parport_release(dev);
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if (selected != daisy) {
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/* No corresponding device. */
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parport_unregister_device(dev);
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return NULL;
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}
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}
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return dev;
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}
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/**
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* parport_close - close a device opened with parport_open()
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* @dev: device to close
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*
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* This is to parport_open() as parport_unregister_device() is to
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* parport_register_device().
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**/
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void parport_close(struct pardevice *dev)
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{
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parport_unregister_device(dev);
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}
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/* Send a daisy-chain-style CPP command packet. */
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static int cpp_daisy(struct parport *port, int cmd)
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{
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unsigned char s;
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parport_data_forward(port);
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parport_write_data(port, 0xaa); udelay(2);
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parport_write_data(port, 0x55); udelay(2);
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parport_write_data(port, 0x00); udelay(2);
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parport_write_data(port, 0xff); udelay(2);
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s = parport_read_status(port) & (PARPORT_STATUS_BUSY
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| PARPORT_STATUS_PAPEROUT
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| PARPORT_STATUS_SELECT
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| PARPORT_STATUS_ERROR);
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if (s != (PARPORT_STATUS_BUSY
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| PARPORT_STATUS_PAPEROUT
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| PARPORT_STATUS_SELECT
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| PARPORT_STATUS_ERROR)) {
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DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff(%02x)\n",
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port->name, s);
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return -ENXIO;
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}
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parport_write_data(port, 0x87); udelay(2);
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s = parport_read_status(port) & (PARPORT_STATUS_BUSY
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| PARPORT_STATUS_PAPEROUT
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| PARPORT_STATUS_SELECT
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| PARPORT_STATUS_ERROR);
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if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
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DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff87(%02x)\n",
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port->name, s);
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return -ENXIO;
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}
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parport_write_data(port, 0x78); udelay(2);
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parport_write_data(port, cmd); udelay(2);
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parport_frob_control(port,
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PARPORT_CONTROL_STROBE,
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PARPORT_CONTROL_STROBE);
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udelay(1);
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s = parport_read_status(port);
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parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
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udelay(1);
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parport_write_data(port, 0xff); udelay(2);
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return s;
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}
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/* Send a mux-style CPP command packet. */
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static int cpp_mux(struct parport *port, int cmd)
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{
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unsigned char s;
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int rc;
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parport_data_forward(port);
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parport_write_data(port, 0xaa); udelay(2);
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parport_write_data(port, 0x55); udelay(2);
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parport_write_data(port, 0xf0); udelay(2);
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parport_write_data(port, 0x0f); udelay(2);
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parport_write_data(port, 0x52); udelay(2);
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parport_write_data(port, 0xad); udelay(2);
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parport_write_data(port, cmd); udelay(2);
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s = parport_read_status(port);
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if (!(s & PARPORT_STATUS_ACK)) {
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DPRINTK(KERN_DEBUG "%s: cpp_mux: aa55f00f52ad%02x(%02x)\n",
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port->name, cmd, s);
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return -EIO;
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}
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rc = (((s & PARPORT_STATUS_SELECT ? 1 : 0) << 0) |
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((s & PARPORT_STATUS_PAPEROUT ? 1 : 0) << 1) |
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((s & PARPORT_STATUS_BUSY ? 0 : 1) << 2) |
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((s & PARPORT_STATUS_ERROR ? 0 : 1) << 3));
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return rc;
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}
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void parport_daisy_deselect_all(struct parport *port)
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{
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cpp_daisy(port, 0x30);
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}
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int parport_daisy_select(struct parport *port, int daisy, int mode)
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{
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switch (mode)
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{
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// For these modes we should switch to EPP mode:
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case IEEE1284_MODE_EPP:
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case IEEE1284_MODE_EPPSL:
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case IEEE1284_MODE_EPPSWE:
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return !(cpp_daisy(port, 0x20 + daisy) &
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PARPORT_STATUS_ERROR);
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// For these modes we should switch to ECP mode:
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case IEEE1284_MODE_ECP:
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case IEEE1284_MODE_ECPRLE:
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case IEEE1284_MODE_ECPSWE:
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return !(cpp_daisy(port, 0xd0 + daisy) &
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PARPORT_STATUS_ERROR);
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// Nothing was told for BECP in Daisy chain specification.
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// May be it's wise to use ECP?
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case IEEE1284_MODE_BECP:
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// Others use compat mode
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case IEEE1284_MODE_NIBBLE:
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case IEEE1284_MODE_BYTE:
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case IEEE1284_MODE_COMPAT:
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default:
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return !(cpp_daisy(port, 0xe0 + daisy) &
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PARPORT_STATUS_ERROR);
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}
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}
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static int mux_present(struct parport *port)
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{
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return cpp_mux(port, 0x51) == 3;
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}
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static int num_mux_ports(struct parport *port)
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{
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return cpp_mux(port, 0x58);
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}
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static int select_port(struct parport *port)
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{
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int muxport = port->muxport;
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return cpp_mux(port, 0x60 + muxport) == muxport;
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}
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static int assign_addrs(struct parport *port)
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{
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unsigned char s;
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unsigned char daisy;
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int thisdev = numdevs;
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int detected;
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char *deviceid;
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parport_data_forward(port);
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parport_write_data(port, 0xaa); udelay(2);
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parport_write_data(port, 0x55); udelay(2);
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parport_write_data(port, 0x00); udelay(2);
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parport_write_data(port, 0xff); udelay(2);
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s = parport_read_status(port) & (PARPORT_STATUS_BUSY
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| PARPORT_STATUS_PAPEROUT
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| PARPORT_STATUS_SELECT
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| PARPORT_STATUS_ERROR);
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if (s != (PARPORT_STATUS_BUSY
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| PARPORT_STATUS_PAPEROUT
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| PARPORT_STATUS_SELECT
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| PARPORT_STATUS_ERROR)) {
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DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff(%02x)\n",
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port->name, s);
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return 0;
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}
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parport_write_data(port, 0x87); udelay(2);
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s = parport_read_status(port) & (PARPORT_STATUS_BUSY
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| PARPORT_STATUS_PAPEROUT
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| PARPORT_STATUS_SELECT
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| PARPORT_STATUS_ERROR);
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if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
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DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff87(%02x)\n",
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port->name, s);
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return 0;
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}
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parport_write_data(port, 0x78); udelay(2);
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s = parport_read_status(port);
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for (daisy = 0;
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(s & (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT))
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== (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT)
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&& daisy < 4;
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++daisy) {
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parport_write_data(port, daisy);
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udelay(2);
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parport_frob_control(port,
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PARPORT_CONTROL_STROBE,
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PARPORT_CONTROL_STROBE);
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udelay(1);
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parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
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udelay(1);
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add_dev(numdevs++, port, daisy);
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/* See if this device thought it was the last in the
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* chain. */
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if (!(s & PARPORT_STATUS_BUSY))
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break;
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/* We are seeing pass through status now. We see
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last_dev from next device or if last_dev does not
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work status lines from some non-daisy chain
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device. */
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s = parport_read_status(port);
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}
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parport_write_data(port, 0xff); udelay(2);
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detected = numdevs - thisdev;
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DPRINTK(KERN_DEBUG "%s: Found %d daisy-chained devices\n", port->name,
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detected);
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/* Ask the new devices to introduce themselves. */
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deviceid = kmalloc(1024, GFP_KERNEL);
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if (!deviceid) return 0;
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for (daisy = 0; thisdev < numdevs; thisdev++, daisy++)
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parport_device_id(thisdev, deviceid, 1024);
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kfree(deviceid);
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return detected;
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}
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