1/*
2 * IEEE-1284 implementation for parport.
3 *
4 * Authors: Phil Blundell <philb@gnu.org>
5 * Carsten Gross <carsten@sol.wohnheim.uni-ulm.de>
6 * Jose Renau <renau@acm.org>
7 * Tim Waugh <tim@cyberelk.demon.co.uk> (largely rewritten)
8 *
9 * This file is responsible for IEEE 1284 negotiation, and for handing
10 * read/write requests to low-level drivers.
11 *
12 * Any part of this program may be used in documents licensed under
13 * the GNU Free Documentation License, Version 1.1 or any later version
14 * published by the Free Software Foundation.
15 *
16 * Various hacks, Fred Barnes <frmb2@ukc.ac.uk>, 04/2000
17 */
18
19#include <linux/module.h>
20#include <linux/threads.h>
21#include <linux/parport.h>
22#include <linux/delay.h>
23#include <linux/kernel.h>
24#include <linux/interrupt.h>
25#include <linux/timer.h>
26#include <linux/sched/signal.h>
27
28#undef DEBUG /* undef me for production */
29
30#ifdef CONFIG_LP_CONSOLE
31#undef DEBUG /* Don't want a garbled console */
32#endif
33
34/* Make parport_wait_peripheral wake up.
35 * It will be useful to call this from an interrupt handler. */
36static void parport_ieee1284_wakeup (struct parport *port)
37{
38 up (sem: &port->physport->ieee1284.irq);
39}
40
41static void timeout_waiting_on_port (struct timer_list *t)
42{
43 struct parport *port = from_timer(port, t, timer);
44
45 parport_ieee1284_wakeup (port);
46}
47
48/**
49 * parport_wait_event - wait for an event on a parallel port
50 * @port: port to wait on
51 * @timeout: time to wait (in jiffies)
52 *
53 * This function waits for up to @timeout jiffies for an
54 * interrupt to occur on a parallel port. If the port timeout is
55 * set to zero, it returns immediately.
56 *
57 * If an interrupt occurs before the timeout period elapses, this
58 * function returns zero immediately. If it times out, it returns
59 * one. An error code less than zero indicates an error (most
60 * likely a pending signal), and the calling code should finish
61 * what it's doing as soon as it can.
62 */
63
64int parport_wait_event (struct parport *port, signed long timeout)
65{
66 int ret;
67
68 if (!port->physport->cad->timeout)
69 /* Zero timeout is special, and we can't down() the
70 semaphore. */
71 return 1;
72
73 timer_setup(&port->timer, timeout_waiting_on_port, 0);
74 mod_timer(timer: &port->timer, expires: jiffies + timeout);
75 ret = down_interruptible (sem: &port->physport->ieee1284.irq);
76 if (!del_timer_sync(timer: &port->timer) && !ret)
77 /* Timed out. */
78 ret = 1;
79
80 return ret;
81}
82
83/**
84 * parport_poll_peripheral - poll status lines
85 * @port: port to watch
86 * @mask: status lines to watch
87 * @result: desired values of chosen status lines
88 * @usec: timeout
89 *
90 * This function busy-waits until the masked status lines have
91 * the desired values, or until the timeout period elapses. The
92 * @mask and @result parameters are bitmasks, with the bits
93 * defined by the constants in parport.h: %PARPORT_STATUS_BUSY,
94 * and so on.
95 *
96 * This function does not call schedule(); instead it busy-waits
97 * using udelay(). It currently has a resolution of 5usec.
98 *
99 * If the status lines take on the desired values before the
100 * timeout period elapses, parport_poll_peripheral() returns zero
101 * immediately. A return value greater than zero indicates
102 * a timeout. An error code (less than zero) indicates an error,
103 * most likely a signal that arrived, and the caller should
104 * finish what it is doing as soon as possible.
105*/
106
107int parport_poll_peripheral(struct parport *port,
108 unsigned char mask,
109 unsigned char result,
110 int usec)
111{
112 /* Zero return code is success, >0 is timeout. */
113 int count = usec / 5 + 2;
114 int i;
115 unsigned char status;
116 for (i = 0; i < count; i++) {
117 status = parport_read_status (port);
118 if ((status & mask) == result)
119 return 0;
120 if (signal_pending (current))
121 return -EINTR;
122 if (need_resched())
123 break;
124 if (i >= 2)
125 udelay (5);
126 }
127
128 return 1;
129}
130
131/**
132 * parport_wait_peripheral - wait for status lines to change in 35ms
133 * @port: port to watch
134 * @mask: status lines to watch
135 * @result: desired values of chosen status lines
136 *
137 * This function waits until the masked status lines have the
138 * desired values, or until 35ms have elapsed (see IEEE 1284-1994
139 * page 24 to 25 for why this value in particular is hardcoded).
140 * The @mask and @result parameters are bitmasks, with the bits
141 * defined by the constants in parport.h: %PARPORT_STATUS_BUSY,
142 * and so on.
143 *
144 * The port is polled quickly to start off with, in anticipation
145 * of a fast response from the peripheral. This fast polling
146 * time is configurable (using /proc), and defaults to 500usec.
147 * If the timeout for this port (see parport_set_timeout()) is
148 * zero, the fast polling time is 35ms, and this function does
149 * not call schedule().
150 *
151 * If the timeout for this port is non-zero, after the fast
152 * polling fails it uses parport_wait_event() to wait for up to
153 * 10ms, waking up if an interrupt occurs.
154 */
155
156int parport_wait_peripheral(struct parport *port,
157 unsigned char mask,
158 unsigned char result)
159{
160 int ret;
161 int usec;
162 unsigned long deadline;
163 unsigned char status;
164
165 usec = port->physport->spintime; /* usecs of fast polling */
166 if (!port->physport->cad->timeout)
167 /* A zero timeout is "special": busy wait for the
168 entire 35ms. */
169 usec = 35000;
170
171 /* Fast polling.
172 *
173 * This should be adjustable.
174 * How about making a note (in the device structure) of how long
175 * it takes, so we know for next time?
176 */
177 ret = parport_poll_peripheral (port, mask, result, usec);
178 if (ret != 1)
179 return ret;
180
181 if (!port->physport->cad->timeout)
182 /* We may be in an interrupt handler, so we can't poll
183 * slowly anyway. */
184 return 1;
185
186 /* 40ms of slow polling. */
187 deadline = jiffies + msecs_to_jiffies(m: 40);
188 while (time_before (jiffies, deadline)) {
189 if (signal_pending (current))
190 return -EINTR;
191
192 /* Wait for 10ms (or until an interrupt occurs if
193 * the handler is set) */
194 if ((ret = parport_wait_event (port, timeout: msecs_to_jiffies(m: 10))) < 0)
195 return ret;
196
197 status = parport_read_status (port);
198 if ((status & mask) == result)
199 return 0;
200
201 if (!ret) {
202 /* parport_wait_event didn't time out, but the
203 * peripheral wasn't actually ready either.
204 * Wait for another 10ms. */
205 schedule_timeout_interruptible(timeout: msecs_to_jiffies(m: 10));
206 }
207 }
208
209 return 1;
210}
211
212#ifdef CONFIG_PARPORT_1284
213/* Terminate a negotiated mode. */
214static void parport_ieee1284_terminate (struct parport *port)
215{
216 int r;
217 port = port->physport;
218
219 /* EPP terminates differently. */
220 switch (port->ieee1284.mode) {
221 case IEEE1284_MODE_EPP:
222 case IEEE1284_MODE_EPPSL:
223 case IEEE1284_MODE_EPPSWE:
224 /* Terminate from EPP mode. */
225
226 /* Event 68: Set nInit low */
227 parport_frob_control (port, PARPORT_CONTROL_INIT, 0);
228 udelay (50);
229
230 /* Event 69: Set nInit high, nSelectIn low */
231 parport_frob_control (port,
232 PARPORT_CONTROL_SELECT
233 | PARPORT_CONTROL_INIT,
234 PARPORT_CONTROL_SELECT
235 | PARPORT_CONTROL_INIT);
236 break;
237
238 case IEEE1284_MODE_ECP:
239 case IEEE1284_MODE_ECPRLE:
240 case IEEE1284_MODE_ECPSWE:
241 /* In ECP we can only terminate from fwd idle phase. */
242 if (port->ieee1284.phase != IEEE1284_PH_FWD_IDLE) {
243 /* Event 47: Set nInit high */
244 parport_frob_control (port,
245 PARPORT_CONTROL_INIT
246 | PARPORT_CONTROL_AUTOFD,
247 PARPORT_CONTROL_INIT
248 | PARPORT_CONTROL_AUTOFD);
249
250 /* Event 49: PError goes high */
251 r = parport_wait_peripheral (port,
252 PARPORT_STATUS_PAPEROUT,
253 PARPORT_STATUS_PAPEROUT);
254 if (r)
255 pr_debug("%s: Timeout at event 49\n",
256 port->name);
257
258 parport_data_forward (port);
259 pr_debug("%s: ECP direction: forward\n", port->name);
260 port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
261 }
262
263 fallthrough;
264
265 default:
266 /* Terminate from all other modes. */
267
268 /* Event 22: Set nSelectIn low, nAutoFd high */
269 parport_frob_control (port,
270 PARPORT_CONTROL_SELECT
271 | PARPORT_CONTROL_AUTOFD,
272 PARPORT_CONTROL_SELECT);
273
274 /* Event 24: nAck goes low */
275 r = parport_wait_peripheral (port, PARPORT_STATUS_ACK, result: 0);
276 if (r)
277 pr_debug("%s: Timeout at event 24\n", port->name);
278
279 /* Event 25: Set nAutoFd low */
280 parport_frob_control (port,
281 PARPORT_CONTROL_AUTOFD,
282 PARPORT_CONTROL_AUTOFD);
283
284 /* Event 27: nAck goes high */
285 r = parport_wait_peripheral (port,
286 PARPORT_STATUS_ACK,
287 PARPORT_STATUS_ACK);
288 if (r)
289 pr_debug("%s: Timeout at event 27\n", port->name);
290
291 /* Event 29: Set nAutoFd high */
292 parport_frob_control (port, PARPORT_CONTROL_AUTOFD, 0);
293 }
294
295 port->ieee1284.mode = IEEE1284_MODE_COMPAT;
296 port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
297
298 pr_debug("%s: In compatibility (forward idle) mode\n", port->name);
299}
300#endif /* IEEE1284 support */
301
302/**
303 * parport_negotiate - negotiate an IEEE 1284 mode
304 * @port: port to use
305 * @mode: mode to negotiate to
306 *
307 * Use this to negotiate to a particular IEEE 1284 transfer mode.
308 * The @mode parameter should be one of the constants in
309 * parport.h starting %IEEE1284_MODE_xxx.
310 *
311 * The return value is 0 if the peripheral has accepted the
312 * negotiation to the mode specified, -1 if the peripheral is not
313 * IEEE 1284 compliant (or not present), or 1 if the peripheral
314 * has rejected the negotiation.
315 */
316
317int parport_negotiate (struct parport *port, int mode)
318{
319#ifndef CONFIG_PARPORT_1284
320 if (mode == IEEE1284_MODE_COMPAT)
321 return 0;
322 pr_err("parport: IEEE1284 not supported in this kernel\n");
323 return -1;
324#else
325 int m = mode & ~IEEE1284_ADDR;
326 int r;
327 unsigned char xflag;
328
329 port = port->physport;
330
331 /* Is there anything to do? */
332 if (port->ieee1284.mode == mode)
333 return 0;
334
335 /* Is the difference just an address-or-not bit? */
336 if ((port->ieee1284.mode & ~IEEE1284_ADDR) == (mode & ~IEEE1284_ADDR)){
337 port->ieee1284.mode = mode;
338 return 0;
339 }
340
341 /* Go to compatibility forward idle mode */
342 if (port->ieee1284.mode != IEEE1284_MODE_COMPAT)
343 parport_ieee1284_terminate (port);
344
345 if (mode == IEEE1284_MODE_COMPAT)
346 /* Compatibility mode: no negotiation. */
347 return 0;
348
349 switch (mode) {
350 case IEEE1284_MODE_ECPSWE:
351 m = IEEE1284_MODE_ECP;
352 break;
353 case IEEE1284_MODE_EPPSL:
354 case IEEE1284_MODE_EPPSWE:
355 m = IEEE1284_MODE_EPP;
356 break;
357 case IEEE1284_MODE_BECP:
358 return -ENOSYS; /* FIXME (implement BECP) */
359 }
360
361 if (mode & IEEE1284_EXT_LINK)
362 m = 1<<7; /* request extensibility link */
363
364 port->ieee1284.phase = IEEE1284_PH_NEGOTIATION;
365
366 /* Start off with nStrobe and nAutoFd high, and nSelectIn low */
367 parport_frob_control (port,
368 PARPORT_CONTROL_STROBE
369 | PARPORT_CONTROL_AUTOFD
370 | PARPORT_CONTROL_SELECT,
371 PARPORT_CONTROL_SELECT);
372 udelay(1);
373
374 /* Event 0: Set data */
375 parport_data_forward (port);
376 parport_write_data (port, m);
377 udelay (400); /* Shouldn't need to wait this long. */
378
379 /* Event 1: Set nSelectIn high, nAutoFd low */
380 parport_frob_control (port,
381 PARPORT_CONTROL_SELECT
382 | PARPORT_CONTROL_AUTOFD,
383 PARPORT_CONTROL_AUTOFD);
384
385 /* Event 2: PError, Select, nFault go high, nAck goes low */
386 if (parport_wait_peripheral (port,
387 PARPORT_STATUS_ERROR
388 | PARPORT_STATUS_SELECT
389 | PARPORT_STATUS_PAPEROUT
390 | PARPORT_STATUS_ACK,
391 PARPORT_STATUS_ERROR
392 | PARPORT_STATUS_SELECT
393 | PARPORT_STATUS_PAPEROUT)) {
394 /* Timeout */
395 parport_frob_control (port,
396 PARPORT_CONTROL_SELECT
397 | PARPORT_CONTROL_AUTOFD,
398 PARPORT_CONTROL_SELECT);
399 pr_debug("%s: Peripheral not IEEE1284 compliant (0x%02X)\n",
400 port->name, parport_read_status (port));
401 port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
402 return -1; /* Not IEEE1284 compliant */
403 }
404
405 /* Event 3: Set nStrobe low */
406 parport_frob_control (port,
407 PARPORT_CONTROL_STROBE,
408 PARPORT_CONTROL_STROBE);
409
410 /* Event 4: Set nStrobe and nAutoFd high */
411 udelay (5);
412 parport_frob_control (port,
413 PARPORT_CONTROL_STROBE
414 | PARPORT_CONTROL_AUTOFD,
415 0);
416
417 /* Event 6: nAck goes high */
418 if (parport_wait_peripheral (port,
419 PARPORT_STATUS_ACK,
420 PARPORT_STATUS_ACK)) {
421 /* This shouldn't really happen with a compliant device. */
422 pr_debug("%s: Mode 0x%02x not supported? (0x%02x)\n",
423 port->name, mode, port->ops->read_status (port));
424 parport_ieee1284_terminate (port);
425 return 1;
426 }
427
428 xflag = parport_read_status (port) & PARPORT_STATUS_SELECT;
429
430 /* xflag should be high for all modes other than nibble (0). */
431 if (mode && !xflag) {
432 /* Mode not supported. */
433 pr_debug("%s: Mode 0x%02x rejected by peripheral\n",
434 port->name, mode);
435 parport_ieee1284_terminate (port);
436 return 1;
437 }
438
439 /* More to do if we've requested extensibility link. */
440 if (mode & IEEE1284_EXT_LINK) {
441 m = mode & 0x7f;
442 udelay (1);
443 parport_write_data (port, m);
444 udelay (1);
445
446 /* Event 51: Set nStrobe low */
447 parport_frob_control (port,
448 PARPORT_CONTROL_STROBE,
449 PARPORT_CONTROL_STROBE);
450
451 /* Event 52: nAck goes low */
452 if (parport_wait_peripheral (port, PARPORT_STATUS_ACK, result: 0)) {
453 /* This peripheral is _very_ slow. */
454 pr_debug("%s: Event 52 didn't happen\n", port->name);
455 parport_ieee1284_terminate (port);
456 return 1;
457 }
458
459 /* Event 53: Set nStrobe high */
460 parport_frob_control (port,
461 PARPORT_CONTROL_STROBE,
462 0);
463
464 /* Event 55: nAck goes high */
465 if (parport_wait_peripheral (port,
466 PARPORT_STATUS_ACK,
467 PARPORT_STATUS_ACK)) {
468 /* This shouldn't really happen with a compliant
469 * device. */
470 pr_debug("%s: Mode 0x%02x not supported? (0x%02x)\n",
471 port->name, mode,
472 port->ops->read_status(port));
473 parport_ieee1284_terminate (port);
474 return 1;
475 }
476
477 /* Event 54: Peripheral sets XFlag to reflect support */
478 xflag = parport_read_status (port) & PARPORT_STATUS_SELECT;
479
480 /* xflag should be high. */
481 if (!xflag) {
482 /* Extended mode not supported. */
483 pr_debug("%s: Extended mode 0x%02x not supported\n",
484 port->name, mode);
485 parport_ieee1284_terminate (port);
486 return 1;
487 }
488
489 /* Any further setup is left to the caller. */
490 }
491
492 /* Mode is supported */
493 pr_debug("%s: In mode 0x%02x\n", port->name, mode);
494 port->ieee1284.mode = mode;
495
496 /* But ECP is special */
497 if (!(mode & IEEE1284_EXT_LINK) && (m & IEEE1284_MODE_ECP)) {
498 port->ieee1284.phase = IEEE1284_PH_ECP_SETUP;
499
500 /* Event 30: Set nAutoFd low */
501 parport_frob_control (port,
502 PARPORT_CONTROL_AUTOFD,
503 PARPORT_CONTROL_AUTOFD);
504
505 /* Event 31: PError goes high. */
506 r = parport_wait_peripheral (port,
507 PARPORT_STATUS_PAPEROUT,
508 PARPORT_STATUS_PAPEROUT);
509 if (r) {
510 pr_debug("%s: Timeout at event 31\n", port->name);
511 }
512
513 port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
514 pr_debug("%s: ECP direction: forward\n", port->name);
515 } else switch (mode) {
516 case IEEE1284_MODE_NIBBLE:
517 case IEEE1284_MODE_BYTE:
518 port->ieee1284.phase = IEEE1284_PH_REV_IDLE;
519 break;
520 default:
521 port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
522 }
523
524
525 return 0;
526#endif /* IEEE1284 support */
527}
528
529/* Acknowledge that the peripheral has data available.
530 * Events 18-20, in order to get from Reverse Idle phase
531 * to Host Busy Data Available.
532 * This will most likely be called from an interrupt.
533 * Returns zero if data was available.
534 */
535#ifdef CONFIG_PARPORT_1284
536static int parport_ieee1284_ack_data_avail (struct parport *port)
537{
538 if (parport_read_status (port) & PARPORT_STATUS_ERROR)
539 /* Event 18 didn't happen. */
540 return -1;
541
542 /* Event 20: nAutoFd goes high. */
543 port->ops->frob_control (port, PARPORT_CONTROL_AUTOFD, 0);
544 port->ieee1284.phase = IEEE1284_PH_HBUSY_DAVAIL;
545 return 0;
546}
547#endif /* IEEE1284 support */
548
549/* Handle an interrupt. */
550void parport_ieee1284_interrupt (void *handle)
551{
552 struct parport *port = handle;
553 parport_ieee1284_wakeup (port);
554
555#ifdef CONFIG_PARPORT_1284
556 if (port->ieee1284.phase == IEEE1284_PH_REV_IDLE) {
557 /* An interrupt in this phase means that data
558 * is now available. */
559 pr_debug("%s: Data available\n", port->name);
560 parport_ieee1284_ack_data_avail (port);
561 }
562#endif /* IEEE1284 support */
563}
564
565/**
566 * parport_write - write a block of data to a parallel port
567 * @port: port to write to
568 * @buffer: data buffer (in kernel space)
569 * @len: number of bytes of data to transfer
570 *
571 * This will write up to @len bytes of @buffer to the port
572 * specified, using the IEEE 1284 transfer mode most recently
573 * negotiated to (using parport_negotiate()), as long as that
574 * mode supports forward transfers (host to peripheral).
575 *
576 * It is the caller's responsibility to ensure that the first
577 * @len bytes of @buffer are valid.
578 *
579 * This function returns the number of bytes transferred (if zero
580 * or positive), or else an error code.
581 */
582
583ssize_t parport_write (struct parport *port, const void *buffer, size_t len)
584{
585#ifndef CONFIG_PARPORT_1284
586 return port->ops->compat_write_data (port, buffer, len, 0);
587#else
588 ssize_t retval;
589 int mode = port->ieee1284.mode;
590 int addr = mode & IEEE1284_ADDR;
591 size_t (*fn) (struct parport *, const void *, size_t, int);
592
593 /* Ignore the device-ID-request bit and the address bit. */
594 mode &= ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
595
596 /* Use the mode we're in. */
597 switch (mode) {
598 case IEEE1284_MODE_NIBBLE:
599 case IEEE1284_MODE_BYTE:
600 parport_negotiate (port, IEEE1284_MODE_COMPAT);
601 fallthrough;
602 case IEEE1284_MODE_COMPAT:
603 pr_debug("%s: Using compatibility mode\n", port->name);
604 fn = port->ops->compat_write_data;
605 break;
606
607 case IEEE1284_MODE_EPP:
608 pr_debug("%s: Using EPP mode\n", port->name);
609 if (addr) {
610 fn = port->ops->epp_write_addr;
611 } else {
612 fn = port->ops->epp_write_data;
613 }
614 break;
615 case IEEE1284_MODE_EPPSWE:
616 pr_debug("%s: Using software-emulated EPP mode\n", port->name);
617 if (addr) {
618 fn = parport_ieee1284_epp_write_addr;
619 } else {
620 fn = parport_ieee1284_epp_write_data;
621 }
622 break;
623 case IEEE1284_MODE_ECP:
624 case IEEE1284_MODE_ECPRLE:
625 pr_debug("%s: Using ECP mode\n", port->name);
626 if (addr) {
627 fn = port->ops->ecp_write_addr;
628 } else {
629 fn = port->ops->ecp_write_data;
630 }
631 break;
632
633 case IEEE1284_MODE_ECPSWE:
634 pr_debug("%s: Using software-emulated ECP mode\n", port->name);
635 /* The caller has specified that it must be emulated,
636 * even if we have ECP hardware! */
637 if (addr) {
638 fn = parport_ieee1284_ecp_write_addr;
639 } else {
640 fn = parport_ieee1284_ecp_write_data;
641 }
642 break;
643
644 default:
645 pr_debug("%s: Unknown mode 0x%02x\n",
646 port->name, port->ieee1284.mode);
647 return -ENOSYS;
648 }
649
650 retval = (*fn) (port, buffer, len, 0);
651 pr_debug("%s: wrote %zd/%zu bytes\n", port->name, retval, len);
652 return retval;
653#endif /* IEEE1284 support */
654}
655
656/**
657 * parport_read - read a block of data from a parallel port
658 * @port: port to read from
659 * @buffer: data buffer (in kernel space)
660 * @len: number of bytes of data to transfer
661 *
662 * This will read up to @len bytes of @buffer to the port
663 * specified, using the IEEE 1284 transfer mode most recently
664 * negotiated to (using parport_negotiate()), as long as that
665 * mode supports reverse transfers (peripheral to host).
666 *
667 * It is the caller's responsibility to ensure that the first
668 * @len bytes of @buffer are available to write to.
669 *
670 * This function returns the number of bytes transferred (if zero
671 * or positive), or else an error code.
672 */
673
674ssize_t parport_read (struct parport *port, void *buffer, size_t len)
675{
676#ifndef CONFIG_PARPORT_1284
677 pr_err("parport: IEEE1284 not supported in this kernel\n");
678 return -ENODEV;
679#else
680 int mode = port->physport->ieee1284.mode;
681 int addr = mode & IEEE1284_ADDR;
682 size_t (*fn) (struct parport *, void *, size_t, int);
683
684 /* Ignore the device-ID-request bit and the address bit. */
685 mode &= ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
686
687 /* Use the mode we're in. */
688 switch (mode) {
689 case IEEE1284_MODE_COMPAT:
690 /* if we can tri-state use BYTE mode instead of NIBBLE mode,
691 * if that fails, revert to NIBBLE mode -- ought to store somewhere
692 * the device's ability to do BYTE mode reverse transfers, so we don't
693 * end up needlessly calling negotiate(BYTE) repeately.. (fb)
694 */
695 if ((port->physport->modes & PARPORT_MODE_TRISTATE) &&
696 !parport_negotiate (port, IEEE1284_MODE_BYTE)) {
697 /* got into BYTE mode OK */
698 pr_debug("%s: Using byte mode\n", port->name);
699 fn = port->ops->byte_read_data;
700 break;
701 }
702 if (parport_negotiate (port, IEEE1284_MODE_NIBBLE)) {
703 return -EIO;
704 }
705 fallthrough; /* to NIBBLE */
706 case IEEE1284_MODE_NIBBLE:
707 pr_debug("%s: Using nibble mode\n", port->name);
708 fn = port->ops->nibble_read_data;
709 break;
710
711 case IEEE1284_MODE_BYTE:
712 pr_debug("%s: Using byte mode\n", port->name);
713 fn = port->ops->byte_read_data;
714 break;
715
716 case IEEE1284_MODE_EPP:
717 pr_debug("%s: Using EPP mode\n", port->name);
718 if (addr) {
719 fn = port->ops->epp_read_addr;
720 } else {
721 fn = port->ops->epp_read_data;
722 }
723 break;
724 case IEEE1284_MODE_EPPSWE:
725 pr_debug("%s: Using software-emulated EPP mode\n", port->name);
726 if (addr) {
727 fn = parport_ieee1284_epp_read_addr;
728 } else {
729 fn = parport_ieee1284_epp_read_data;
730 }
731 break;
732 case IEEE1284_MODE_ECP:
733 case IEEE1284_MODE_ECPRLE:
734 pr_debug("%s: Using ECP mode\n", port->name);
735 fn = port->ops->ecp_read_data;
736 break;
737
738 case IEEE1284_MODE_ECPSWE:
739 pr_debug("%s: Using software-emulated ECP mode\n", port->name);
740 fn = parport_ieee1284_ecp_read_data;
741 break;
742
743 default:
744 pr_debug("%s: Unknown mode 0x%02x\n",
745 port->name, port->physport->ieee1284.mode);
746 return -ENOSYS;
747 }
748
749 return (*fn) (port, buffer, len, 0);
750#endif /* IEEE1284 support */
751}
752
753/**
754 * parport_set_timeout - set the inactivity timeout for a device
755 * @dev: device on a port
756 * @inactivity: inactivity timeout (in jiffies)
757 *
758 * This sets the inactivity timeout for a particular device on a
759 * port. This affects functions like parport_wait_peripheral().
760 * The special value 0 means not to call schedule() while dealing
761 * with this device.
762 *
763 * The return value is the previous inactivity timeout.
764 *
765 * Any callers of parport_wait_event() for this device are woken
766 * up.
767 */
768
769long parport_set_timeout (struct pardevice *dev, long inactivity)
770{
771 long int old = dev->timeout;
772
773 dev->timeout = inactivity;
774
775 if (dev->port->physport->cad == dev)
776 parport_ieee1284_wakeup (port: dev->port);
777
778 return old;
779}
780
781/* Exported symbols for modules. */
782
783EXPORT_SYMBOL(parport_negotiate);
784EXPORT_SYMBOL(parport_write);
785EXPORT_SYMBOL(parport_read);
786EXPORT_SYMBOL(parport_wait_peripheral);
787EXPORT_SYMBOL(parport_wait_event);
788EXPORT_SYMBOL(parport_set_timeout);
789EXPORT_SYMBOL(parport_ieee1284_interrupt);
790

source code of linux/drivers/parport/ieee1284.c