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