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