1/*
2 * IEEE 1284.3 Parallel port daisy chain and multiplexor code
3 *
4 * Copyright (C) 1999, 2000  Tim Waugh <tim@cyberelk.demon.co.uk>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 * ??-12-1998: Initial implementation.
12 * 31-01-1999: Make port-cloning transparent.
13 * 13-02-1999: Move DeviceID technique from parport_probe.
14 * 13-03-1999: Get DeviceID from non-IEEE 1284.3 devices too.
15 * 22-02-2000: Count devices that are actually detected.
16 *
17 * Any part of this program may be used in documents licensed under
18 * the GNU Free Documentation License, Version 1.1 or any later version
19 * published by the Free Software Foundation.
20 */
21
22#include <linux/module.h>
23#include <linux/parport.h>
24#include <linux/delay.h>
25#include <linux/sched.h>
26
27#include <asm/current.h>
28#include <asm/uaccess.h>
29
30#undef DEBUG
31
32#ifdef DEBUG
33#define DPRINTK(stuff...) printk(stuff)
34#else
35#define DPRINTK(stuff...)
36#endif
37
38static struct daisydev {
39	struct daisydev *next;
40	struct parport *port;
41	int daisy;
42	int devnum;
43} *topology = NULL;
44static DEFINE_SPINLOCK(topology_lock);
45
46static int numdevs = 0;
47
48/* Forward-declaration of lower-level functions. */
49static int mux_present(struct parport *port);
50static int num_mux_ports(struct parport *port);
51static int select_port(struct parport *port);
52static int assign_addrs(struct parport *port);
53
54/* Add a device to the discovered topology. */
55static void add_dev(int devnum, struct parport *port, int daisy)
56{
57	struct daisydev *newdev, **p;
58	newdev = kmalloc(sizeof(struct daisydev), GFP_KERNEL);
59	if (newdev) {
60		newdev->port = port;
61		newdev->daisy = daisy;
62		newdev->devnum = devnum;
63		spin_lock(&topology_lock);
64		for (p = &topology; *p && (*p)->devnum<devnum; p = &(*p)->next)
65			;
66		newdev->next = *p;
67		*p = newdev;
68		spin_unlock(&topology_lock);
69	}
70}
71
72/* Clone a parport (actually, make an alias). */
73static struct parport *clone_parport(struct parport *real, int muxport)
74{
75	struct parport *extra = parport_register_port(real->base,
76						       real->irq,
77						       real->dma,
78						       real->ops);
79	if (extra) {
80		extra->portnum = real->portnum;
81		extra->physport = real;
82		extra->muxport = muxport;
83		real->slaves[muxport-1] = extra;
84	}
85
86	return extra;
87}
88
89/* Discover the IEEE1284.3 topology on a port -- muxes and daisy chains.
90 * Return value is number of devices actually detected. */
91int parport_daisy_init(struct parport *port)
92{
93	int detected = 0;
94	char *deviceid;
95	static const char *th[] = { /*0*/"th", "st", "nd", "rd", "th" };
96	int num_ports;
97	int i;
98	int last_try = 0;
99
100again:
101	/* Because this is called before any other devices exist,
102	 * we don't have to claim exclusive access.  */
103
104	/* If mux present on normal port, need to create new
105	 * parports for each extra port. */
106	if (port->muxport < 0 && mux_present(port) &&
107	    /* don't be fooled: a mux must have 2 or 4 ports. */
108	    ((num_ports = num_mux_ports(port)) == 2 || num_ports == 4)) {
109		/* Leave original as port zero. */
110		port->muxport = 0;
111		printk(KERN_INFO
112			"%s: 1st (default) port of %d-way multiplexor\n",
113			port->name, num_ports);
114		for (i = 1; i < num_ports; i++) {
115			/* Clone the port. */
116			struct parport *extra = clone_parport(port, i);
117			if (!extra) {
118				if (signal_pending(current))
119					break;
120
121				schedule();
122				continue;
123			}
124
125			printk(KERN_INFO
126				"%s: %d%s port of %d-way multiplexor on %s\n",
127				extra->name, i + 1, th[i + 1], num_ports,
128				port->name);
129
130			/* Analyse that port too.  We won't recurse
131			   forever because of the 'port->muxport < 0'
132			   test above. */
133			parport_daisy_init(extra);
134		}
135	}
136
137	if (port->muxport >= 0)
138		select_port(port);
139
140	parport_daisy_deselect_all(port);
141	detected += assign_addrs(port);
142
143	/* Count the potential legacy device at the end. */
144	add_dev(numdevs++, port, -1);
145
146	/* Find out the legacy device's IEEE 1284 device ID. */
147	deviceid = kmalloc(1024, GFP_KERNEL);
148	if (deviceid) {
149		if (parport_device_id(numdevs - 1, deviceid, 1024) > 2)
150			detected++;
151
152		kfree(deviceid);
153	}
154
155	if (!detected && !last_try) {
156		/* No devices were detected.  Perhaps they are in some
157                   funny state; let's try to reset them and see if
158                   they wake up. */
159		parport_daisy_fini(port);
160		parport_write_control(port, PARPORT_CONTROL_SELECT);
161		udelay(50);
162		parport_write_control(port,
163				       PARPORT_CONTROL_SELECT |
164				       PARPORT_CONTROL_INIT);
165		udelay(50);
166		last_try = 1;
167		goto again;
168	}
169
170	return detected;
171}
172
173/* Forget about devices on a physical port. */
174void parport_daisy_fini(struct parport *port)
175{
176	struct daisydev **p;
177
178	spin_lock(&topology_lock);
179	p = &topology;
180	while (*p) {
181		struct daisydev *dev = *p;
182		if (dev->port != port) {
183			p = &dev->next;
184			continue;
185		}
186		*p = dev->next;
187		kfree(dev);
188	}
189
190	/* Gaps in the numbering could be handled better.  How should
191           someone enumerate through all IEEE1284.3 devices in the
192           topology?. */
193	if (!topology) numdevs = 0;
194	spin_unlock(&topology_lock);
195	return;
196}
197
198/**
199 *	parport_open - find a device by canonical device number
200 *	@devnum: canonical device number
201 *	@name: name to associate with the device
202 *	@pf: preemption callback
203 *	@kf: kick callback
204 *	@irqf: interrupt handler
205 *	@flags: registration flags
206 *	@handle: driver data
207 *
208 *	This function is similar to parport_register_device(), except
209 *	that it locates a device by its number rather than by the port
210 *	it is attached to.
211 *
212 *	All parameters except for @devnum are the same as for
213 *	parport_register_device().  The return value is the same as
214 *	for parport_register_device().
215 **/
216
217struct pardevice *parport_open(int devnum, const char *name,
218				int (*pf) (void *), void (*kf) (void *),
219				void (*irqf) (int, void *),
220				int flags, void *handle)
221{
222	struct daisydev *p = topology;
223	struct parport *port;
224	struct pardevice *dev;
225	int daisy;
226
227	spin_lock(&topology_lock);
228	while (p && p->devnum != devnum)
229		p = p->next;
230
231	if (!p) {
232		spin_unlock(&topology_lock);
233		return NULL;
234	}
235
236	daisy = p->daisy;
237	port = parport_get_port(p->port);
238	spin_unlock(&topology_lock);
239
240	dev = parport_register_device(port, name, pf, kf,
241				       irqf, flags, handle);
242	parport_put_port(port);
243	if (!dev)
244		return NULL;
245
246	dev->daisy = daisy;
247
248	/* Check that there really is a device to select. */
249	if (daisy >= 0) {
250		int selected;
251		parport_claim_or_block(dev);
252		selected = port->daisy;
253		parport_release(dev);
254
255		if (selected != daisy) {
256			/* No corresponding device. */
257			parport_unregister_device(dev);
258			return NULL;
259		}
260	}
261
262	return dev;
263}
264
265/**
266 *	parport_close - close a device opened with parport_open()
267 *	@dev: device to close
268 *
269 *	This is to parport_open() as parport_unregister_device() is to
270 *	parport_register_device().
271 **/
272
273void parport_close(struct pardevice *dev)
274{
275	parport_unregister_device(dev);
276}
277
278/**
279 *	parport_device_num - convert device coordinates
280 *	@parport: parallel port number
281 *	@mux: multiplexor port number (-1 for no multiplexor)
282 *	@daisy: daisy chain address (-1 for no daisy chain address)
283 *
284 *	This tries to locate a device on the given parallel port,
285 *	multiplexor port and daisy chain address, and returns its
286 *	device number or %-ENXIO if no device with those coordinates
287 *	exists.
288 **/
289
290int parport_device_num(int parport, int mux, int daisy)
291{
292	int res = -ENXIO;
293	struct daisydev *dev;
294
295	spin_lock(&topology_lock);
296	dev = topology;
297	while (dev && dev->port->portnum != parport &&
298	       dev->port->muxport != mux && dev->daisy != daisy)
299		dev = dev->next;
300	if (dev)
301		res = dev->devnum;
302	spin_unlock(&topology_lock);
303
304	return res;
305}
306
307/* Send a daisy-chain-style CPP command packet. */
308static int cpp_daisy(struct parport *port, int cmd)
309{
310	unsigned char s;
311
312	parport_data_forward(port);
313	parport_write_data(port, 0xaa); udelay(2);
314	parport_write_data(port, 0x55); udelay(2);
315	parport_write_data(port, 0x00); udelay(2);
316	parport_write_data(port, 0xff); udelay(2);
317	s = parport_read_status(port) & (PARPORT_STATUS_BUSY
318					  | PARPORT_STATUS_PAPEROUT
319					  | PARPORT_STATUS_SELECT
320					  | PARPORT_STATUS_ERROR);
321	if (s != (PARPORT_STATUS_BUSY
322		  | PARPORT_STATUS_PAPEROUT
323		  | PARPORT_STATUS_SELECT
324		  | PARPORT_STATUS_ERROR)) {
325		DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff(%02x)\n",
326			 port->name, s);
327		return -ENXIO;
328	}
329
330	parport_write_data(port, 0x87); udelay(2);
331	s = parport_read_status(port) & (PARPORT_STATUS_BUSY
332					  | PARPORT_STATUS_PAPEROUT
333					  | PARPORT_STATUS_SELECT
334					  | PARPORT_STATUS_ERROR);
335	if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
336		DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff87(%02x)\n",
337			 port->name, s);
338		return -ENXIO;
339	}
340
341	parport_write_data(port, 0x78); udelay(2);
342	parport_write_data(port, cmd); udelay(2);
343	parport_frob_control(port,
344			      PARPORT_CONTROL_STROBE,
345			      PARPORT_CONTROL_STROBE);
346	udelay(1);
347	s = parport_read_status(port);
348	parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
349	udelay(1);
350	parport_write_data(port, 0xff); udelay(2);
351
352	return s;
353}
354
355/* Send a mux-style CPP command packet. */
356static int cpp_mux(struct parport *port, int cmd)
357{
358	unsigned char s;
359	int rc;
360
361	parport_data_forward(port);
362	parport_write_data(port, 0xaa); udelay(2);
363	parport_write_data(port, 0x55); udelay(2);
364	parport_write_data(port, 0xf0); udelay(2);
365	parport_write_data(port, 0x0f); udelay(2);
366	parport_write_data(port, 0x52); udelay(2);
367	parport_write_data(port, 0xad); udelay(2);
368	parport_write_data(port, cmd); udelay(2);
369
370	s = parport_read_status(port);
371	if (!(s & PARPORT_STATUS_ACK)) {
372		DPRINTK(KERN_DEBUG "%s: cpp_mux: aa55f00f52ad%02x(%02x)\n",
373			 port->name, cmd, s);
374		return -EIO;
375	}
376
377	rc = (((s & PARPORT_STATUS_SELECT   ? 1 : 0) << 0) |
378	      ((s & PARPORT_STATUS_PAPEROUT ? 1 : 0) << 1) |
379	      ((s & PARPORT_STATUS_BUSY     ? 0 : 1) << 2) |
380	      ((s & PARPORT_STATUS_ERROR    ? 0 : 1) << 3));
381
382	return rc;
383}
384
385void parport_daisy_deselect_all(struct parport *port)
386{
387	cpp_daisy(port, 0x30);
388}
389
390int parport_daisy_select(struct parport *port, int daisy, int mode)
391{
392	switch (mode)
393	{
394		// For these modes we should switch to EPP mode:
395		case IEEE1284_MODE_EPP:
396		case IEEE1284_MODE_EPPSL:
397		case IEEE1284_MODE_EPPSWE:
398			return !(cpp_daisy(port, 0x20 + daisy) &
399				 PARPORT_STATUS_ERROR);
400
401		// For these modes we should switch to ECP mode:
402		case IEEE1284_MODE_ECP:
403		case IEEE1284_MODE_ECPRLE:
404		case IEEE1284_MODE_ECPSWE:
405			return !(cpp_daisy(port, 0xd0 + daisy) &
406				 PARPORT_STATUS_ERROR);
407
408		// Nothing was told for BECP in Daisy chain specification.
409		// May be it's wise to use ECP?
410		case IEEE1284_MODE_BECP:
411		// Others use compat mode
412		case IEEE1284_MODE_NIBBLE:
413		case IEEE1284_MODE_BYTE:
414		case IEEE1284_MODE_COMPAT:
415		default:
416			return !(cpp_daisy(port, 0xe0 + daisy) &
417				 PARPORT_STATUS_ERROR);
418	}
419}
420
421static int mux_present(struct parport *port)
422{
423	return cpp_mux(port, 0x51) == 3;
424}
425
426static int num_mux_ports(struct parport *port)
427{
428	return cpp_mux(port, 0x58);
429}
430
431static int select_port(struct parport *port)
432{
433	int muxport = port->muxport;
434	return cpp_mux(port, 0x60 + muxport) == muxport;
435}
436
437static int assign_addrs(struct parport *port)
438{
439	unsigned char s;
440	unsigned char daisy;
441	int thisdev = numdevs;
442	int detected;
443	char *deviceid;
444
445	parport_data_forward(port);
446	parport_write_data(port, 0xaa); udelay(2);
447	parport_write_data(port, 0x55); udelay(2);
448	parport_write_data(port, 0x00); udelay(2);
449	parport_write_data(port, 0xff); udelay(2);
450	s = parport_read_status(port) & (PARPORT_STATUS_BUSY
451					  | PARPORT_STATUS_PAPEROUT
452					  | PARPORT_STATUS_SELECT
453					  | PARPORT_STATUS_ERROR);
454	if (s != (PARPORT_STATUS_BUSY
455		  | PARPORT_STATUS_PAPEROUT
456		  | PARPORT_STATUS_SELECT
457		  | PARPORT_STATUS_ERROR)) {
458		DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff(%02x)\n",
459			 port->name, s);
460		return 0;
461	}
462
463	parport_write_data(port, 0x87); udelay(2);
464	s = parport_read_status(port) & (PARPORT_STATUS_BUSY
465					  | PARPORT_STATUS_PAPEROUT
466					  | PARPORT_STATUS_SELECT
467					  | PARPORT_STATUS_ERROR);
468	if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
469		DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff87(%02x)\n",
470			 port->name, s);
471		return 0;
472	}
473
474	parport_write_data(port, 0x78); udelay(2);
475	s = parport_read_status(port);
476
477	for (daisy = 0;
478	     (s & (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT))
479		     == (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT)
480		     && daisy < 4;
481	     ++daisy) {
482		parport_write_data(port, daisy);
483		udelay(2);
484		parport_frob_control(port,
485				      PARPORT_CONTROL_STROBE,
486				      PARPORT_CONTROL_STROBE);
487		udelay(1);
488		parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
489		udelay(1);
490
491		add_dev(numdevs++, port, daisy);
492
493		/* See if this device thought it was the last in the
494		 * chain. */
495		if (!(s & PARPORT_STATUS_BUSY))
496			break;
497
498		/* We are seeing pass through status now. We see
499		   last_dev from next device or if last_dev does not
500		   work status lines from some non-daisy chain
501		   device. */
502		s = parport_read_status(port);
503	}
504
505	parport_write_data(port, 0xff); udelay(2);
506	detected = numdevs - thisdev;
507	DPRINTK(KERN_DEBUG "%s: Found %d daisy-chained devices\n", port->name,
508		 detected);
509
510	/* Ask the new devices to introduce themselves. */
511	deviceid = kmalloc(1024, GFP_KERNEL);
512	if (!deviceid) return 0;
513
514	for (daisy = 0; thisdev < numdevs; thisdev++, daisy++)
515		parport_device_id(thisdev, deviceid, 1024);
516
517	kfree(deviceid);
518	return detected;
519}
520