1 /* $Id: parport_ieee1284.c,v 1.4 1997/10/19 21:37:21 philip Exp $
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.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 #ifdef DEBUG
35 #define DPRINTK(stuff...) printk (stuff)
36 #else
37 #define DPRINTK(stuff...)
38 #endif
39
40 /* Make parport_wait_peripheral wake up.
41 * It will be useful to call this from an interrupt handler. */
42 static void parport_ieee1284_wakeup (struct parport *port)
43 {
44 up (&port->physport->ieee1284.irq);
45 }
46
47 static struct parport *port_from_cookie[PARPORT_MAX];
48 static void timeout_waiting_on_port (unsigned long cookie)
49 {
50 parport_ieee1284_wakeup (port_from_cookie[cookie % PARPORT_MAX]);
51 }
52
53 /**
54 * parport_wait_event - wait for an event on a parallel port
55 * @port: port to wait on
56 * @timeout: time to wait (in jiffies)
57 *
58 * This function waits for up to @timeout jiffies for an
59 * interrupt to occur on a parallel port. If the port timeout is
60 * set to zero, it returns immediately.
61 *
62 * If an interrupt occurs before the timeout period elapses, this
63 * function returns zero immediately. If it times out, it returns
64 * one. An error code less than zero indicates an error (most
65 * likely a pending signal), and the calling code should finish
66 * what it's doing as soon as it can.
67 */
68
69 int parport_wait_event (struct parport *port, signed long timeout)
70 {
71 int ret;
72 struct timer_list timer;
73
74 if (!port->physport->cad->timeout)
75 /* Zero timeout is special, and we can't down() the
76 semaphore. */
77 return 1;
78
79 init_timer (&timer);
80 timer.expires = jiffies + timeout;
81 timer.function = timeout_waiting_on_port;
82 port_from_cookie[port->number % PARPORT_MAX] = port;
83 timer.data = port->number;
84
85 add_timer (&timer);
86 ret = down_interruptible (&port->physport->ieee1284.irq);
87 if (!del_timer (&timer) && !ret)
88 /* Timed out. */
89 ret = 1;
90
91 return ret;
92 }
93
94 /**
95 * parport_poll_peripheral - poll status lines
96 * @port: port to watch
97 * @mask: status lines to watch
98 * @result: desired values of chosen status lines
99 * @usec: timeout
100 *
101 * This function busy-waits until the masked status lines have
102 * the desired values, or until the timeout period elapses. The
103 * @mask and @result parameters are bitmasks, with the bits
104 * defined by the constants in parport.h: %PARPORT_STATUS_BUSY,
105 * and so on.
106 *
107 * This function does not call schedule(); instead it busy-waits
108 * using udelay(). It currently has a resolution of 5usec.
109 *
110 * If the status lines take on the desired values before the
111 * timeout period elapses, parport_poll_peripheral() returns zero
112 * immediately. A return value greater than zero indicates
113 * a timeout. An error code (less than zero) indicates an error,
114 * most likely a signal that arrived, and the caller should
115 * finish what it is doing as soon as possible.
116 */
117
118 int parport_poll_peripheral(struct parport *port,
119 unsigned char mask,
120 unsigned char result,
121 int usec)
122 {
123 /* Zero return code is success, >0 is timeout. */
124 int count = usec / 5 + 2;
125 int i;
126 unsigned char status;
127 for (i = 0; i < count; i++) {
128 status = parport_read_status (port);
129 if ((status & mask) == result)
130 return 0;
131 if (signal_pending (current))
132 return -EINTR;
133 if (need_resched())
134 break;
135 if (i >= 2)
136 udelay (5);
137 }
138
139 return 1;
140 }
141
142 /**
143 * parport_wait_peripheral - wait for status lines to change in 35ms
144 * @port: port to watch
145 * @mask: status lines to watch
146 * @result: desired values of chosen status lines
147 *
148 * This function waits until the masked status lines have the
149 * desired values, or until 35ms have elapsed (see IEEE 1284-1994
150 * page 24 to 25 for why this value in particular is hardcoded).
151 * The @mask and @result parameters are bitmasks, with the bits
152 * defined by the constants in parport.h: %PARPORT_STATUS_BUSY,
153 * and so on.
154 *
155 * The port is polled quickly to start off with, in anticipation
156 * of a fast response from the peripheral. This fast polling
157 * time is configurable (using /proc), and defaults to 500usec.
158 * If the timeout for this port (see parport_set_timeout()) is
159 * zero, the fast polling time is 35ms, and this function does
160 * not call schedule().
161 *
162 * If the timeout for this port is non-zero, after the fast
163 * polling fails it uses parport_wait_event() to wait for up to
164 * 10ms, waking up if an interrupt occurs.
165 */
166
167 int parport_wait_peripheral(struct parport *port,
168 unsigned char mask,
169 unsigned char result)
170 {
171 int ret;
172 int usec;
173 unsigned long deadline;
174 unsigned char status;
175
176 usec = port->physport->spintime; /* usecs of fast polling */
177 if (!port->physport->cad->timeout)
178 /* A zero timeout is "special": busy wait for the
179 entire 35ms. */
180 usec = 35000;
181
182 /* Fast polling.
183 *
184 * This should be adjustable.
185 * How about making a note (in the device structure) of how long
186 * it takes, so we know for next time?
187 */
188 ret = parport_poll_peripheral (port, mask, result, usec);
189 if (ret != 1)
190 return ret;
191
192 if (!port->physport->cad->timeout)
193 /* We may be in an interrupt handler, so we can't poll
194 * slowly anyway. */
195 return 1;
196
197 /* 40ms of slow polling. */
198 deadline = jiffies + msecs_to_jiffies(40);
199 while (time_before (jiffies, deadline)) {
200 int ret;
201
202 if (signal_pending (current))
203 return -EINTR;
204
205 /* Wait for 10ms (or until an interrupt occurs if
206 * the handler is set) */
207 if ((ret = parport_wait_event (port, msecs_to_jiffies(10))) < 0)
208 return ret;
209
210 status = parport_read_status (port);
211 if ((status & mask) == result)
212 return 0;
213
214 if (!ret) {
215 /* parport_wait_event didn't time out, but the
216 * peripheral wasn't actually ready either.
217 * Wait for another 10ms. */
218 schedule_timeout_interruptible(msecs_to_jiffies(10));
219 }
220 }
221
222 return 1;
223 }
224
225 #ifdef CONFIG_PARPORT_1284
226 /* Terminate a negotiated mode. */
227 static void parport_ieee1284_terminate (struct parport *port)
228 {
229 int r;
230 port = port->physport;
231
232 /* EPP terminates differently. */
233 switch (port->ieee1284.mode) {
234 case IEEE1284_MODE_EPP:
235 case IEEE1284_MODE_EPPSL:
236 case IEEE1284_MODE_EPPSWE:
237 /* Terminate from EPP mode. */
238
239 /* Event 68: Set nInit low */
240 parport_frob_control (port, PARPORT_CONTROL_INIT, 0);
241 udelay (50);
242
243 /* Event 69: Set nInit high, nSelectIn low */
244 parport_frob_control (port,
245 PARPORT_CONTROL_SELECT
246 | PARPORT_CONTROL_INIT,
247 PARPORT_CONTROL_SELECT
248 | PARPORT_CONTROL_INIT);
249 break;
250
251 case IEEE1284_MODE_ECP:
252 case IEEE1284_MODE_ECPRLE:
253 case IEEE1284_MODE_ECPSWE:
254 /* In ECP we can only terminate from fwd idle phase. */
255 if (port->ieee1284.phase != IEEE1284_PH_FWD_IDLE) {
256 /* Event 47: Set nInit high */
257 parport_frob_control (port,
258 PARPORT_CONTROL_INIT
259 | PARPORT_CONTROL_AUTOFD,
260 PARPORT_CONTROL_INIT
261 | PARPORT_CONTROL_AUTOFD);
262
263 /* Event 49: PError goes high */
264 r = parport_wait_peripheral (port,
265 PARPORT_STATUS_PAPEROUT,
266 PARPORT_STATUS_PAPEROUT);
267 if (r)
268 DPRINTK (KERN_INFO "%s: Timeout at event 49\n",
269 port->name);
270
271 parport_data_forward (port);
272 DPRINTK (KERN_DEBUG "%s: ECP direction: forward\n",
273 port->name);
274 port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
275 }
276
277 /* fall-though.. */
278
279 default:
280 /* Terminate from all other modes. */
281
282 /* Event 22: Set nSelectIn low, nAutoFd high */
283 parport_frob_control (port,
284 PARPORT_CONTROL_SELECT
285 | PARPORT_CONTROL_AUTOFD,
286 PARPORT_CONTROL_SELECT);
287
288 /* Event 24: nAck goes low */
289 r = parport_wait_peripheral (port, PARPORT_STATUS_ACK, 0);
290 if (r)
291 DPRINTK (KERN_INFO "%s: Timeout at event 24\n",
292 port->name);
293
294 /* Event 25: Set nAutoFd low */
295 parport_frob_control (port,
296 PARPORT_CONTROL_AUTOFD,
297 PARPORT_CONTROL_AUTOFD);
298
299 /* Event 27: nAck goes high */
300 r = parport_wait_peripheral (port,
301 PARPORT_STATUS_ACK,
302 PARPORT_STATUS_ACK);
303 if (r)
304 DPRINTK (KERN_INFO "%s: Timeout at event 27\n",
305 port->name);
306
307 /* Event 29: Set nAutoFd high */
308 parport_frob_control (port, PARPORT_CONTROL_AUTOFD, 0);
309 }
310
311 port->ieee1284.mode = IEEE1284_MODE_COMPAT;
312 port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
313
314 DPRINTK (KERN_DEBUG "%s: In compatibility (forward idle) mode\n",
315 port->name);
316 }
317 #endif /* IEEE1284 support */
318
319 /**
320 * parport_negotiate - negotiate an IEEE 1284 mode
321 * @port: port to use
322 * @mode: mode to negotiate to
323 *
324 * Use this to negotiate to a particular IEEE 1284 transfer mode.
325 * The @mode parameter should be one of the constants in
326 * parport.h starting %IEEE1284_MODE_xxx.
327 *
328 * The return value is 0 if the peripheral has accepted the
329 * negotiation to the mode specified, -1 if the peripheral is not
330 * IEEE 1284 compliant (or not present), or 1 if the peripheral
331 * has rejected the negotiation.
332 */
333
334 int parport_negotiate (struct parport *port, int mode)
335 {
336 #ifndef CONFIG_PARPORT_1284
337 if (mode == IEEE1284_MODE_COMPAT)
338 return 0;
339 printk (KERN_ERR "parport: IEEE1284 not supported in this kernel\n");
340 return -1;
341 #else
342 int m = mode & ~IEEE1284_ADDR;
343 int r;
344 unsigned char xflag;
345
346 port = port->physport;
347
348 /* Is there anything to do? */
349 if (port->ieee1284.mode == mode)
350 return 0;
351
352 /* Is the difference just an address-or-not bit? */
353 if ((port->ieee1284.mode & ~IEEE1284_ADDR) == (mode & ~IEEE1284_ADDR)){
354 port->ieee1284.mode = mode;
355 return 0;
356 }
357
358 /* Go to compability forward idle mode */
359 if (port->ieee1284.mode != IEEE1284_MODE_COMPAT)
360 parport_ieee1284_terminate (port);
361
362 if (mode == IEEE1284_MODE_COMPAT)
363 /* Compatibility mode: no negotiation. */
364 return 0;
365
366 switch (mode) {
367 case IEEE1284_MODE_ECPSWE:
368 m = IEEE1284_MODE_ECP;
369 break;
370 case IEEE1284_MODE_EPPSL:
371 case IEEE1284_MODE_EPPSWE:
372 m = IEEE1284_MODE_EPP;
373 break;
374 case IEEE1284_MODE_BECP:
375 return -ENOSYS; /* FIXME (implement BECP) */
376 }
377
378 if (mode & IEEE1284_EXT_LINK)
379 m = 1<<7; /* request extensibility link */
380
381 port->ieee1284.phase = IEEE1284_PH_NEGOTIATION;
382
383 /* Start off with nStrobe and nAutoFd high, and nSelectIn low */
384 parport_frob_control (port,
385 PARPORT_CONTROL_STROBE
386 | PARPORT_CONTROL_AUTOFD
387 | PARPORT_CONTROL_SELECT,
388 PARPORT_CONTROL_SELECT);
389 udelay(1);
390
391 /* Event 0: Set data */
392 parport_data_forward (port);
393 parport_write_data (port, m);
394 udelay (400); /* Shouldn't need to wait this long. */
395
396 /* Event 1: Set nSelectIn high, nAutoFd low */
397 parport_frob_control (port,
398 PARPORT_CONTROL_SELECT
399 | PARPORT_CONTROL_AUTOFD,
400 PARPORT_CONTROL_AUTOFD);
401
402 /* Event 2: PError, Select, nFault go high, nAck goes low */
403 if (parport_wait_peripheral (port,
404 PARPORT_STATUS_ERROR
405 | PARPORT_STATUS_SELECT
406 | PARPORT_STATUS_PAPEROUT
407 | PARPORT_STATUS_ACK,
408 PARPORT_STATUS_ERROR
409 | PARPORT_STATUS_SELECT
410 | PARPORT_STATUS_PAPEROUT)) {
411 /* Timeout */
412 parport_frob_control (port,
413 PARPORT_CONTROL_SELECT
414 | PARPORT_CONTROL_AUTOFD,
415 PARPORT_CONTROL_SELECT);
416 DPRINTK (KERN_DEBUG
417 "%s: Peripheral not IEEE1284 compliant (0x%02X)\n",
418 port->name, parport_read_status (port));
419 port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
420 return -1; /* Not IEEE1284 compliant */
421 }
422
423 /* Event 3: Set nStrobe low */
424 parport_frob_control (port,
425 PARPORT_CONTROL_STROBE,
426 PARPORT_CONTROL_STROBE);
427
428 /* Event 4: Set nStrobe and nAutoFd high */
429 udelay (5);
430 parport_frob_control (port,
431 PARPORT_CONTROL_STROBE
432 | PARPORT_CONTROL_AUTOFD,
433 0);
434
435 /* Event 6: nAck goes high */
436 if (parport_wait_peripheral (port,
437 PARPORT_STATUS_ACK,
438 PARPORT_STATUS_ACK)) {
439 /* This shouldn't really happen with a compliant device. */
440 DPRINTK (KERN_DEBUG
441 "%s: Mode 0x%02x not supported? (0x%02x)\n",
442 port->name, mode, port->ops->read_status (port));
443 parport_ieee1284_terminate (port);
444 return 1;
445 }
446
447 xflag = parport_read_status (port) & PARPORT_STATUS_SELECT;
448
449 /* xflag should be high for all modes other than nibble (0). */
450 if (mode && !xflag) {
451 /* Mode not supported. */
452 DPRINTK (KERN_DEBUG "%s: Mode 0x%02x rejected by peripheral\n",
453 port->name, mode);
454 parport_ieee1284_terminate (port);
455 return 1;
456 }
457
458 /* More to do if we've requested extensibility link. */
459 if (mode & IEEE1284_EXT_LINK) {
460 m = mode & 0x7f;
461 udelay (1);
462 parport_write_data (port, m);
463 udelay (1);
464
465 /* Event 51: Set nStrobe low */
466 parport_frob_control (port,
467 PARPORT_CONTROL_STROBE,
468 PARPORT_CONTROL_STROBE);
469
470 /* Event 52: nAck goes low */
471 if (parport_wait_peripheral (port, PARPORT_STATUS_ACK, 0)) {
472 /* This peripheral is _very_ slow. */
473 DPRINTK (KERN_DEBUG
474 "%s: Event 52 didn't happen\n",
475 port->name);
476 parport_ieee1284_terminate (port);
477 return 1;
478 }
479
480 /* Event 53: Set nStrobe high */
481 parport_frob_control (port,
482 PARPORT_CONTROL_STROBE,
483 0);
484
485 /* Event 55: nAck goes high */
486 if (parport_wait_peripheral (port,
487 PARPORT_STATUS_ACK,
488 PARPORT_STATUS_ACK)) {
489 /* This shouldn't really happen with a compliant
490 * device. */
491 DPRINTK (KERN_DEBUG
492 "%s: Mode 0x%02x not supported? (0x%02x)\n",
493 port->name, mode,
494 port->ops->read_status (port));
495 parport_ieee1284_terminate (port);
496 return 1;
497 }
498
499 /* Event 54: Peripheral sets XFlag to reflect support */
500 xflag = parport_read_status (port) & PARPORT_STATUS_SELECT;
501
502 /* xflag should be high. */
503 if (!xflag) {
504 /* Extended mode not supported. */
505 DPRINTK (KERN_DEBUG "%s: Extended mode 0x%02x not "
506 "supported\n", port->name, mode);
507 parport_ieee1284_terminate (port);
508 return 1;
509 }
510
511 /* Any further setup is left to the caller. */
512 }
513
514 /* Mode is supported */
515 DPRINTK (KERN_DEBUG "%s: In mode 0x%02x\n", port->name, mode);
516 port->ieee1284.mode = mode;
517
518 /* But ECP is special */
519 if (!(mode & IEEE1284_EXT_LINK) && (m & IEEE1284_MODE_ECP)) {
520 port->ieee1284.phase = IEEE1284_PH_ECP_SETUP;
521
522 /* Event 30: Set nAutoFd low */
523 parport_frob_control (port,
524 PARPORT_CONTROL_AUTOFD,
525 PARPORT_CONTROL_AUTOFD);
526
527 /* Event 31: PError goes high. */
528 r = parport_wait_peripheral (port,
529 PARPORT_STATUS_PAPEROUT,
530 PARPORT_STATUS_PAPEROUT);
531 if (r) {
532 DPRINTK (KERN_INFO "%s: Timeout at event 31\n",
533 port->name);
534 }
535
536 port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
537 DPRINTK (KERN_DEBUG "%s: ECP direction: forward\n",
538 port->name);
539 } else switch (mode) {
540 case IEEE1284_MODE_NIBBLE:
541 case IEEE1284_MODE_BYTE:
542 port->ieee1284.phase = IEEE1284_PH_REV_IDLE;
543 break;
544 default:
545 port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
546 }
547
548
549 return 0;
550 #endif /* IEEE1284 support */
551 }
552
553 /* Acknowledge that the peripheral has data available.
554 * Events 18-20, in order to get from Reverse Idle phase
555 * to Host Busy Data Available.
556 * This will most likely be called from an interrupt.
557 * Returns zero if data was available.
558 */
559 #ifdef CONFIG_PARPORT_1284
560 static int parport_ieee1284_ack_data_avail (struct parport *port)
561 {
562 if (parport_read_status (port) & PARPORT_STATUS_ERROR)
563 /* Event 18 didn't happen. */
564 return -1;
565
566 /* Event 20: nAutoFd goes high. */
567 port->ops->frob_control (port, PARPORT_CONTROL_AUTOFD, 0);
568 port->ieee1284.phase = IEEE1284_PH_HBUSY_DAVAIL;
569 return 0;
570 }
571 #endif /* IEEE1284 support */
572
573 /* Handle an interrupt. */
574 void parport_ieee1284_interrupt (void *handle)
575 {
576 struct parport *port = handle;
577 parport_ieee1284_wakeup (port);
578
579 #ifdef CONFIG_PARPORT_1284
580 if (port->ieee1284.phase == IEEE1284_PH_REV_IDLE) {
581 /* An interrupt in this phase means that data
582 * is now available. */
583 DPRINTK (KERN_DEBUG "%s: Data available\n", port->name);
584 parport_ieee1284_ack_data_avail (port);
585 }
586 #endif /* IEEE1284 support */
587 }
588
589 /**
590 * parport_write - write a block of data to a parallel port
591 * @port: port to write to
592 * @buffer: data buffer (in kernel space)
593 * @len: number of bytes of data to transfer
594 *
595 * This will write up to @len bytes of @buffer to the port
596 * specified, using the IEEE 1284 transfer mode most recently
597 * negotiated to (using parport_negotiate()), as long as that
598 * mode supports forward transfers (host to peripheral).
599 *
600 * It is the caller's responsibility to ensure that the first
601 * @len bytes of @buffer are valid.
602 *
603 * This function returns the number of bytes transferred (if zero
604 * or positive), or else an error code.
605 */
606
607 ssize_t parport_write (struct parport *port, const void *buffer, size_t len)
608 {
609 #ifndef CONFIG_PARPORT_1284
610 return port->ops->compat_write_data (port, buffer, len, 0);
611 #else
612 ssize_t retval;
613 int mode = port->ieee1284.mode;
614 int addr = mode & IEEE1284_ADDR;
615 size_t (*fn) (struct parport *, const void *, size_t, int);
616
617 /* Ignore the device-ID-request bit and the address bit. */
618 mode &= ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
619
620 /* Use the mode we're in. */
621 switch (mode) {
622 case IEEE1284_MODE_NIBBLE:
623 case IEEE1284_MODE_BYTE:
624 parport_negotiate (port, IEEE1284_MODE_COMPAT);
625 case IEEE1284_MODE_COMPAT:
626 DPRINTK (KERN_DEBUG "%s: Using compatibility mode\n",
627 port->name);
628 fn = port->ops->compat_write_data;
629 break;
630
631 case IEEE1284_MODE_EPP:
632 DPRINTK (KERN_DEBUG "%s: Using EPP mode\n", port->name);
633 if (addr) {
634 fn = port->ops->epp_write_addr;
635 } else {
636 fn = port->ops->epp_write_data;
637 }
638 break;
639 case IEEE1284_MODE_EPPSWE:
640 DPRINTK (KERN_DEBUG "%s: Using software-emulated EPP mode\n",
641 port->name);
642 if (addr) {
643 fn = parport_ieee1284_epp_write_addr;
644 } else {
645 fn = parport_ieee1284_epp_write_data;
646 }
647 break;
648 case IEEE1284_MODE_ECP:
649 case IEEE1284_MODE_ECPRLE:
650 DPRINTK (KERN_DEBUG "%s: Using ECP mode\n", port->name);
651 if (addr) {
652 fn = port->ops->ecp_write_addr;
653 } else {
654 fn = port->ops->ecp_write_data;
655 }
656 break;
657
658 case IEEE1284_MODE_ECPSWE:
659 DPRINTK (KERN_DEBUG "%s: Using software-emulated ECP mode\n",
660 port->name);
661 /* The caller has specified that it must be emulated,
662 * even if we have ECP hardware! */
663 if (addr) {
664 fn = parport_ieee1284_ecp_write_addr;
665 } else {
666 fn = parport_ieee1284_ecp_write_data;
667 }
668 break;
669
670 default:
671 DPRINTK (KERN_DEBUG "%s: Unknown mode 0x%02x\n", port->name,
672 port->ieee1284.mode);
673 return -ENOSYS;
674 }
675
676 retval = (*fn) (port, buffer, len, 0);
677 DPRINTK (KERN_DEBUG "%s: wrote %d/%d bytes\n", port->name, retval, len);
678 return retval;
679 #endif /* IEEE1284 support */
680 }
681
682 /**
683 * parport_read - read a block of data from a parallel port
684 * @port: port to read from
685 * @buffer: data buffer (in kernel space)
686 * @len: number of bytes of data to transfer
687 *
688 * This will read up to @len bytes of @buffer to the port
689 * specified, using the IEEE 1284 transfer mode most recently
690 * negotiated to (using parport_negotiate()), as long as that
691 * mode supports reverse transfers (peripheral to host).
692 *
693 * It is the caller's responsibility to ensure that the first
694 * @len bytes of @buffer are available to write to.
695 *
696 * This function returns the number of bytes transferred (if zero
697 * or positive), or else an error code.
698 */
699
700 ssize_t parport_read (struct parport *port, void *buffer, size_t len)
701 {
702 #ifndef CONFIG_PARPORT_1284
703 printk (KERN_ERR "parport: IEEE1284 not supported in this kernel\n");
704 return -ENODEV;
705 #else
706 int mode = port->physport->ieee1284.mode;
707 int addr = mode & IEEE1284_ADDR;
708 size_t (*fn) (struct parport *, void *, size_t, int);
709
710 /* Ignore the device-ID-request bit and the address bit. */
711 mode &= ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
712
713 /* Use the mode we're in. */
714 switch (mode) {
715 case IEEE1284_MODE_COMPAT:
716 /* if we can tri-state use BYTE mode instead of NIBBLE mode,
717 * if that fails, revert to NIBBLE mode -- ought to store somewhere
718 * the device's ability to do BYTE mode reverse transfers, so we don't
719 * end up needlessly calling negotiate(BYTE) repeately.. (fb)
720 */
721 if ((port->physport->modes & PARPORT_MODE_TRISTATE) &&
722 !parport_negotiate (port, IEEE1284_MODE_BYTE)) {
723 /* got into BYTE mode OK */
724 DPRINTK (KERN_DEBUG "%s: Using byte mode\n", port->name);
725 fn = port->ops->byte_read_data;
726 break;
727 }
728 if (parport_negotiate (port, IEEE1284_MODE_NIBBLE)) {
729 return -EIO;
730 }
731 /* fall through to NIBBLE */
732 case IEEE1284_MODE_NIBBLE:
733 DPRINTK (KERN_DEBUG "%s: Using nibble mode\n", port->name);
734 fn = port->ops->nibble_read_data;
735 break;
736
737 case IEEE1284_MODE_BYTE:
738 DPRINTK (KERN_DEBUG "%s: Using byte mode\n", port->name);
739 fn = port->ops->byte_read_data;
740 break;
741
742 case IEEE1284_MODE_EPP:
743 DPRINTK (KERN_DEBUG "%s: Using EPP mode\n", port->name);
744 if (addr) {
745 fn = port->ops->epp_read_addr;
746 } else {
747 fn = port->ops->epp_read_data;
748 }
749 break;
750 case IEEE1284_MODE_EPPSWE:
751 DPRINTK (KERN_DEBUG "%s: Using software-emulated EPP mode\n",
752 port->name);
753 if (addr) {
754 fn = parport_ieee1284_epp_read_addr;
755 } else {
756 fn = parport_ieee1284_epp_read_data;
757 }
758 break;
759 case IEEE1284_MODE_ECP:
760 case IEEE1284_MODE_ECPRLE:
761 DPRINTK (KERN_DEBUG "%s: Using ECP mode\n", port->name);
762 fn = port->ops->ecp_read_data;
763 break;
764
765 case IEEE1284_MODE_ECPSWE:
766 DPRINTK (KERN_DEBUG "%s: Using software-emulated ECP mode\n",
767 port->name);
768 fn = parport_ieee1284_ecp_read_data;
769 break;
770
771 default:
772 DPRINTK (KERN_DEBUG "%s: Unknown mode 0x%02x\n", port->name,
773 port->physport->ieee1284.mode);
774 return -ENOSYS;
775 }
776
777 return (*fn) (port, buffer, len, 0);
778 #endif /* IEEE1284 support */
779 }
780
781 /**
782 * parport_set_timeout - set the inactivity timeout for a device
783 * @dev: device on a port
784 * @inactivity: inactivity timeout (in jiffies)
785 *
786 * This sets the inactivity timeout for a particular device on a
787 * port. This affects functions like parport_wait_peripheral().
788 * The special value 0 means not to call schedule() while dealing
789 * with this device.
790 *
791 * The return value is the previous inactivity timeout.
792 *
793 * Any callers of parport_wait_event() for this device are woken
794 * up.
795 */
796
797 long parport_set_timeout (struct pardevice *dev, long inactivity)
798 {
799 long int old = dev->timeout;
800
801 dev->timeout = inactivity;
802
803 if (dev->port->physport->cad == dev)
804 parport_ieee1284_wakeup (dev->port);
805
806 return old;
807 }
808
809 /* Exported symbols for modules. */
810
811 EXPORT_SYMBOL(parport_negotiate);
812 EXPORT_SYMBOL(parport_write);
813 EXPORT_SYMBOL(parport_read);
814 EXPORT_SYMBOL(parport_wait_peripheral);
815 EXPORT_SYMBOL(parport_wait_event);
816 EXPORT_SYMBOL(parport_set_timeout);
817 EXPORT_SYMBOL(parport_ieee1284_interrupt);
818
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