aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/parport/daisy.c
blob: 5bed17f68ef4d164bdef53a22c6c0c65c6e83e8c (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
/*
 * 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 <asm/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 (s != (PARPORT_STATUS_BUSY
		  | PARPORT_STATUS_PAPEROUT
		  | PARPORT_STATUS_SELECT
		  | PARPORT_STATUS_ERROR)) {
		DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff(%02x)\n",
			 port->name, s);
		return -ENXIO;
	}

	parport_write_data(port, 0x87); udelay(2);
	s = parport_read_status(port) & (PARPORT_STATUS_BUSY
					  | PARPORT_STATUS_PAPEROUT
					  | PARPORT_STATUS_SELECT
					  | PARPORT_STATUS_ERROR);
	if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
		DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff87(%02x)\n",
			 port->name, s);
		return -ENXIO;
	}

	parport_write_data(port, 0x78); udelay(2);
	parport_write_data(port, cmd); udelay(2);
	parport_frob_control(port,
			      PARPORT_CONTROL_STROBE,
			      PARPORT_CONTROL_STROBE);
	udelay(1);
	s = parport_read_status(port);
	parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
	udelay(1);
	parport_write_data(port, 0xff); udelay(2);

	return s;
}

/* Send a mux-style CPP command packet. */
static int cpp_mux(struct parport *port, int cmd)
{
	unsigned char s;
	int rc;

	parport_data_forward(port);
	parport_write_data(port, 0xaa); udelay(2);
	parport_write_data(port, 0x55); udelay(2);
	parport_write_data(port, 0xf0); udelay(2);
	parport_write_data(port, 0x0f); udelay(2);
	parport_write_data(port, 0x52); udelay(2);
	parport_write_data(port, 0xad); udelay(2);
	parport_write_data(port, cmd); udelay(2);

	s = parport_read_status(port);
	if (!(s & PARPORT_STATUS_ACK)) {
		DPRINTK(KERN_DEBUG "%s: cpp_mux: aa55f00f52ad%02x(%02x)\n",
			 port->name, cmd, s);
		return -EIO;
	}

	rc = (((s & PARPORT_STATUS_SELECT   ? 1 : 0) << 0) |
	      ((s & PARPORT_STATUS_PAPEROUT ? 1 : 0) << 1) |
	      ((s & PARPORT_STATUS_BUSY     ? 0 : 1) << 2) |
	      ((s & PARPORT_STATUS_ERROR    ? 0 : 1) << 3));

	return rc;
}

void parport_daisy_deselect_all(struct parport *port)
{
	cpp_daisy(port, 0x30);
}

int parport_daisy_select(struct parport *port, int daisy, int mode)
{
	switch (mode)
	{
		// For these modes we should switch to EPP mode:
		case IEEE1284_MODE_EPP:
		case IEEE1284_MODE_EPPSL:
		case IEEE1284_MODE_EPPSWE:
			return !(cpp_daisy(port, 0x20 + daisy) &
				 PARPORT_STATUS_ERROR);

		// For these modes we should switch to ECP mode:
		case IEEE1284_MODE_ECP:
		case IEEE1284_MODE_ECPRLE:
		case IEEE1284_MODE_ECPSWE: 
			return !(cpp_daisy(port, 0xd0 + daisy) &
				 PARPORT_STATUS_ERROR);

		// Nothing was told for BECP in Daisy chain specification.
		// May be it's wise to use ECP?
		case IEEE1284_MODE_BECP:
		// Others use compat mode
		case IEEE1284_MODE_NIBBLE:
		case IEEE1284_MODE_BYTE:
		case IEEE1284_MODE_COMPAT:
		default:
			return !(cpp_daisy(port, 0xe0 + daisy) &
				 PARPORT_STATUS_ERROR);
	}
}

static int mux_present(struct parport *port)
{
	return cpp_mux(port, 0x51) == 3;
}

static int num_mux_ports(struct parport *port)
{
	return cpp_mux(port, 0x58);
}

static int select_port(struct parport *port)
{
	int muxport = port->muxport;
	return cpp_mux(port, 0x60 + muxport) == muxport;
}

static int assign_addrs(struct parport *port)
{
	unsigned char s;
	unsigned char daisy;
	int thisdev = numdevs;
	int detected;
	char *deviceid;

	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 (s != (PARPORT_STATUS_BUSY
		  | PARPORT_STATUS_PAPEROUT
		  | PARPORT_STATUS_SELECT
		  | PARPORT_STATUS_ERROR)) {
		DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff(%02x)\n",
			 port->name, s);
		return 0;
	}

	parport_write_data(port, 0x87); udelay(2);
	s = parport_read_status(port) & (PARPORT_STATUS_BUSY
					  | PARPORT_STATUS_PAPEROUT
					  | PARPORT_STATUS_SELECT
					  | PARPORT_STATUS_ERROR);
	if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
		DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff87(%02x)\n",
			 port->name, s);
		return 0;
	}

	parport_write_data(port, 0x78); udelay(2);
	s = parport_read_status(port);

	for (daisy = 0;
	     (s & (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT))
		     == (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT)
		     && daisy < 4;
	     ++daisy) {
		parport_write_data(port, daisy);
		udelay(2);
		parport_frob_control(port,
				      PARPORT_CONTROL_STROBE,
				      PARPORT_CONTROL_STROBE);
		udelay(1);
		parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
		udelay(1);

		add_dev(numdevs++, port, daisy);

		/* See if this device thought it was the last in the
		 * chain. */
		if (!(s & PARPORT_STATUS_BUSY))
			break;

		/* We are seeing pass through status now. We see
		   last_dev from next device or if last_dev does not
		   work status lines from some non-daisy chain
		   device. */
		s = parport_read_status(port);
	}

	parport_write_data(port, 0xff); udelay(2);
	detected = numdevs - thisdev;
	DPRINTK(KERN_DEBUG "%s: Found %d daisy-chained devices\n", port->name,
		 detected);

	/* Ask the new devices to introduce themselves. */
	deviceid = kmalloc(1024, GFP_KERNEL);
	if (!deviceid) return 0;

	for (daisy = 0; thisdev < numdevs; thisdev++, daisy++)
		parport_device_id(thisdev, deviceid, 1024);

	kfree(deviceid);
	return detected;
}