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
39 static struct daisydev {
40 struct daisydev *next;
41 struct parport *port;
42 int daisy;
43 int devnum;
44 } *topology = NULL;
45 static DEFINE_SPINLOCK(topology_lock);
46
47 static int numdevs = 0;
48
49 /* Forward-declaration of lower-level functions. */
50 static int mux_present(struct parport *port);
51 static int num_mux_ports(struct parport *port);
52 static int select_port(struct parport *port);
53 static int assign_addrs(struct parport *port);
54
55 /* Add a device to the discovered topology. */
add_dev(int devnum,struct parport * port,int daisy)56 static 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). */
clone_parport(struct parport * real,int muxport)74 static 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. */
parport_daisy_init(struct parport * port)92 int 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
101 again:
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. */
parport_daisy_fini(struct parport * port)175 void 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
parport_open(int devnum,const char * name)213 struct 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
parport_close(struct pardevice * dev)265 void parport_close(struct pardevice *dev)
266 {
267 parport_unregister_device(dev);
268 }
269
270 /* Send a daisy-chain-style CPP command packet. */
cpp_daisy(struct parport * port,int cmd)271 static 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. */
cpp_mux(struct parport * port,int cmd)319 static 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
parport_daisy_deselect_all(struct parport * port)348 void parport_daisy_deselect_all(struct parport *port)
349 {
350 cpp_daisy(port, 0x30);
351 }
352
parport_daisy_select(struct parport * port,int daisy,int mode)353 int 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
mux_present(struct parport * port)384 static int mux_present(struct parport *port)
385 {
386 return cpp_mux(port, 0x51) == 3;
387 }
388
num_mux_ports(struct parport * port)389 static int num_mux_ports(struct parport *port)
390 {
391 return cpp_mux(port, 0x58);
392 }
393
select_port(struct parport * port)394 static int select_port(struct parport *port)
395 {
396 int muxport = port->muxport;
397 return cpp_mux(port, 0x60 + muxport) == muxport;
398 }
399
assign_addrs(struct parport * port)400 static 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