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1/*
2 * Parallel-port resource manager code.
3 *
4 * Authors: David Campbell <campbell@tirian.che.curtin.edu.au>
5 * Tim Waugh <tim@cyberelk.demon.co.uk>
6 * Jose Renau <renau@acm.org>
7 * Philip Blundell <philb@gnu.org>
8 * Andrea Arcangeli
9 *
10 * based on work by Grant Guenther <grant@torque.net>
11 * and Philip Blundell
12 *
13 * Any part of this program may be used in documents licensed under
14 * the GNU Free Documentation License, Version 1.1 or any later version
15 * published by the Free Software Foundation.
16 */
17
18#undef PARPORT_DEBUG_SHARING /* undef for production */
19
20#include <linux/module.h>
21#include <linux/string.h>
22#include <linux/threads.h>
23#include <linux/parport.h>
24#include <linux/delay.h>
25#include <linux/errno.h>
26#include <linux/interrupt.h>
27#include <linux/ioport.h>
28#include <linux/kernel.h>
29#include <linux/slab.h>
30#include <linux/sched.h>
31#include <linux/kmod.h>
32
33#include <linux/spinlock.h>
34#include <linux/mutex.h>
35#include <asm/irq.h>
36
37#undef PARPORT_PARANOID
38
39#define PARPORT_DEFAULT_TIMESLICE (HZ/5)
40
41unsigned long parport_default_timeslice = PARPORT_DEFAULT_TIMESLICE;
42int parport_default_spintime = DEFAULT_SPIN_TIME;
43
44static LIST_HEAD(portlist);
45static DEFINE_SPINLOCK(parportlist_lock);
46
47/* list of all allocated ports, sorted by ->number */
48static LIST_HEAD(all_ports);
49static DEFINE_SPINLOCK(full_list_lock);
50
51static LIST_HEAD(drivers);
52
53static DEFINE_MUTEX(registration_lock);
54
55/* What you can do to a port that's gone away.. */
56static void dead_write_lines (struct parport *p, unsigned char b){}
57static unsigned char dead_read_lines (struct parport *p) { return 0; }
58static unsigned char dead_frob_lines (struct parport *p, unsigned char b,
59 unsigned char c) { return 0; }
60static void dead_onearg (struct parport *p){}
61static void dead_initstate (struct pardevice *d, struct parport_state *s) { }
62static void dead_state (struct parport *p, struct parport_state *s) { }
63static size_t dead_write (struct parport *p, const void *b, size_t l, int f)
64{ return 0; }
65static size_t dead_read (struct parport *p, void *b, size_t l, int f)
66{ return 0; }
67static struct parport_operations dead_ops = {
68 .write_data = dead_write_lines, /* data */
69 .read_data = dead_read_lines,
70
71 .write_control = dead_write_lines, /* control */
72 .read_control = dead_read_lines,
73 .frob_control = dead_frob_lines,
74
75 .read_status = dead_read_lines, /* status */
76
77 .enable_irq = dead_onearg, /* enable_irq */
78 .disable_irq = dead_onearg, /* disable_irq */
79
80 .data_forward = dead_onearg, /* data_forward */
81 .data_reverse = dead_onearg, /* data_reverse */
82
83 .init_state = dead_initstate, /* init_state */
84 .save_state = dead_state,
85 .restore_state = dead_state,
86
87 .epp_write_data = dead_write, /* epp */
88 .epp_read_data = dead_read,
89 .epp_write_addr = dead_write,
90 .epp_read_addr = dead_read,
91
92 .ecp_write_data = dead_write, /* ecp */
93 .ecp_read_data = dead_read,
94 .ecp_write_addr = dead_write,
95
96 .compat_write_data = dead_write, /* compat */
97 .nibble_read_data = dead_read, /* nibble */
98 .byte_read_data = dead_read, /* byte */
99
100 .owner = NULL,
101};
102
103/* Call attach(port) for each registered driver. */
104static void attach_driver_chain(struct parport *port)
105{
106 /* caller has exclusive registration_lock */
107 struct parport_driver *drv;
108 list_for_each_entry(drv, &drivers, list)
109 drv->attach(port);
110}
111
112/* Call detach(port) for each registered driver. */
113static void detach_driver_chain(struct parport *port)
114{
115 struct parport_driver *drv;
116 /* caller has exclusive registration_lock */
117 list_for_each_entry(drv, &drivers, list)
118 drv->detach (port);
119}
120
121/* Ask kmod for some lowlevel drivers. */
122static void get_lowlevel_driver (void)
123{
124 /* There is no actual module called this: you should set
125 * up an alias for modutils. */
126 request_module ("parport_lowlevel");
127}
128
129/**
130 * parport_register_driver - register a parallel port device driver
131 * @drv: structure describing the driver
132 *
133 * This can be called by a parallel port device driver in order
134 * to receive notifications about ports being found in the
135 * system, as well as ports no longer available.
136 *
137 * The @drv structure is allocated by the caller and must not be
138 * deallocated until after calling parport_unregister_driver().
139 *
140 * The driver's attach() function may block. The port that
141 * attach() is given will be valid for the duration of the
142 * callback, but if the driver wants to take a copy of the
143 * pointer it must call parport_get_port() to do so. Calling
144 * parport_register_device() on that port will do this for you.
145 *
146 * The driver's detach() function may block. The port that
147 * detach() is given will be valid for the duration of the
148 * callback, but if the driver wants to take a copy of the
149 * pointer it must call parport_get_port() to do so.
150 *
151 * Returns 0 on success. Currently it always succeeds.
152 **/
153
154int parport_register_driver (struct parport_driver *drv)
155{
156 struct parport *port;
157
158 if (list_empty(&portlist))
159 get_lowlevel_driver ();
160
161 mutex_lock(®istration_lock);
162 list_for_each_entry(port, &portlist, list)
163 drv->attach(port);
164 list_add(&drv->list, &drivers);
165 mutex_unlock(®istration_lock);
166
167 return 0;
168}
169
170/**
171 * parport_unregister_driver - deregister a parallel port device driver
172 * @drv: structure describing the driver that was given to
173 * parport_register_driver()
174 *
175 * This should be called by a parallel port device driver that
176 * has registered itself using parport_register_driver() when it
177 * is about to be unloaded.
178 *
179 * When it returns, the driver's attach() routine will no longer
180 * be called, and for each port that attach() was called for, the
181 * detach() routine will have been called.
182 *
183 * All the driver's attach() and detach() calls are guaranteed to have
184 * finished by the time this function returns.
185 **/
186
187void parport_unregister_driver (struct parport_driver *drv)
188{
189 struct parport *port;
190
191 mutex_lock(®istration_lock);
192 list_del_init(&drv->list);
193 list_for_each_entry(port, &portlist, list)
194 drv->detach(port);
195 mutex_unlock(®istration_lock);
196}
197
198static void free_port (struct parport *port)
199{
200 int d;
201 spin_lock(&full_list_lock);
202 list_del(&port->full_list);
203 spin_unlock(&full_list_lock);
204 for (d = 0; d < 5; d++) {
205 kfree(port->probe_info[d].class_name);
206 kfree(port->probe_info[d].mfr);
207 kfree(port->probe_info[d].model);
208 kfree(port->probe_info[d].cmdset);
209 kfree(port->probe_info[d].description);
210 }
211
212 kfree(port->name);
213 kfree(port);
214}
215
216/**
217 * parport_get_port - increment a port's reference count
218 * @port: the port
219 *
220 * This ensures that a struct parport pointer remains valid
221 * until the matching parport_put_port() call.
222 **/
223
224struct parport *parport_get_port (struct parport *port)
225{
226 atomic_inc (&port->ref_count);
227 return port;
228}
229
230/**
231 * parport_put_port - decrement a port's reference count
232 * @port: the port
233 *
234 * This should be called once for each call to parport_get_port(),
235 * once the port is no longer needed.
236 **/
237
238void parport_put_port (struct parport *port)
239{
240 if (atomic_dec_and_test (&port->ref_count))
241 /* Can destroy it now. */
242 free_port (port);
243
244 return;
245}
246
247/**
248 * parport_register_port - register a parallel port
249 * @base: base I/O address
250 * @irq: IRQ line
251 * @dma: DMA channel
252 * @ops: pointer to the port driver's port operations structure
253 *
254 * When a parallel port (lowlevel) driver finds a port that
255 * should be made available to parallel port device drivers, it
256 * should call parport_register_port(). The @base, @irq, and
257 * @dma parameters are for the convenience of port drivers, and
258 * for ports where they aren't meaningful needn't be set to
259 * anything special. They can be altered afterwards by adjusting
260 * the relevant members of the parport structure that is returned
261 * and represents the port. They should not be tampered with
262 * after calling parport_announce_port, however.
263 *
264 * If there are parallel port device drivers in the system that
265 * have registered themselves using parport_register_driver(),
266 * they are not told about the port at this time; that is done by
267 * parport_announce_port().
268 *
269 * The @ops structure is allocated by the caller, and must not be
270 * deallocated before calling parport_remove_port().
271 *
272 * If there is no memory to allocate a new parport structure,
273 * this function will return %NULL.
274 **/
275
276struct parport *parport_register_port(unsigned long base, int irq, int dma,
277 struct parport_operations *ops)
278{
279 struct list_head *l;
280 struct parport *tmp;
281 int num;
282 int device;
283 char *name;
284
285 tmp = kmalloc(sizeof(struct parport), GFP_KERNEL);
286 if (!tmp) {
287 printk(KERN_WARNING "parport: memory squeeze\n");
288 return NULL;
289 }
290
291 /* Init our structure */
292 memset(tmp, 0, sizeof(struct parport));
293 tmp->base = base;
294 tmp->irq = irq;
295 tmp->dma = dma;
296 tmp->muxport = tmp->daisy = tmp->muxsel = -1;
297 tmp->modes = 0;
298 INIT_LIST_HEAD(&tmp->list);
299 tmp->devices = tmp->cad = NULL;
300 tmp->flags = 0;
301 tmp->ops = ops;
302 tmp->physport = tmp;
303 memset (tmp->probe_info, 0, 5 * sizeof (struct parport_device_info));
304 rwlock_init(&tmp->cad_lock);
305 spin_lock_init(&tmp->waitlist_lock);
306 spin_lock_init(&tmp->pardevice_lock);
307 tmp->ieee1284.mode = IEEE1284_MODE_COMPAT;
308 tmp->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
309 sema_init(&tmp->ieee1284.irq, 0);
310 tmp->spintime = parport_default_spintime;
311 atomic_set (&tmp->ref_count, 1);
312 INIT_LIST_HEAD(&tmp->full_list);
313
314 name = kmalloc(15, GFP_KERNEL);
315 if (!name) {
316 printk(KERN_ERR "parport: memory squeeze\n");
317 kfree(tmp);
318 return NULL;
319 }
320 /* Search for the lowest free parport number. */
321
322 spin_lock(&full_list_lock);
323 for (l = all_ports.next, num = 0; l != &all_ports; l = l->next, num++) {
324 struct parport *p = list_entry(l, struct parport, full_list);
325 if (p->number != num)
326 break;
327 }
328 tmp->portnum = tmp->number = num;
329 list_add_tail(&tmp->full_list, l);
330 spin_unlock(&full_list_lock);
331
332 /*
333 * Now that the portnum is known finish doing the Init.
334 */
335 sprintf(name, "parport%d", tmp->portnum = tmp->number);
336 tmp->name = name;
337
338 for (device = 0; device < 5; device++)
339 /* assume the worst */
340 tmp->probe_info[device].class = PARPORT_CLASS_LEGACY;
341
342 tmp->waithead = tmp->waittail = NULL;
343
344 return tmp;
345}
346
347/**
348 * parport_announce_port - tell device drivers about a parallel port
349 * @port: parallel port to announce
350 *
351 * After a port driver has registered a parallel port with
352 * parport_register_port, and performed any necessary
353 * initialisation or adjustments, it should call
354 * parport_announce_port() in order to notify all device drivers
355 * that have called parport_register_driver(). Their attach()
356 * functions will be called, with @port as the parameter.
357 **/
358
359void parport_announce_port (struct parport *port)
360{
361 int i;
362
363#ifdef CONFIG_PARPORT_1284
364 /* Analyse the IEEE1284.3 topology of the port. */
365 parport_daisy_init(port);
366#endif
367
368 if (!port->dev)
369 printk(KERN_WARNING "%s: fix this legacy "
370 "no-device port driver!\n",
371 port->name);
372
373 parport_proc_register(port);
374 mutex_lock(®istration_lock);
375 spin_lock_irq(&parportlist_lock);
376 list_add_tail(&port->list, &portlist);
377 for (i = 1; i < 3; i++) {
378 struct parport *slave = port->slaves[i-1];
379 if (slave)
380 list_add_tail(&slave->list, &portlist);
381 }
382 spin_unlock_irq(&parportlist_lock);
383
384 /* Let drivers know that new port(s) has arrived. */
385 attach_driver_chain (port);
386 for (i = 1; i < 3; i++) {
387 struct parport *slave = port->slaves[i-1];
388 if (slave)
389 attach_driver_chain(slave);
390 }
391 mutex_unlock(®istration_lock);
392}
393
394/**
395 * parport_remove_port - deregister a parallel port
396 * @port: parallel port to deregister
397 *
398 * When a parallel port driver is forcibly unloaded, or a
399 * parallel port becomes inaccessible, the port driver must call
400 * this function in order to deal with device drivers that still
401 * want to use it.
402 *
403 * The parport structure associated with the port has its
404 * operations structure replaced with one containing 'null'
405 * operations that return errors or just don't do anything.
406 *
407 * Any drivers that have registered themselves using
408 * parport_register_driver() are notified that the port is no
409 * longer accessible by having their detach() routines called
410 * with @port as the parameter.
411 **/
412
413void parport_remove_port(struct parport *port)
414{
415 int i;
416
417 mutex_lock(®istration_lock);
418
419 /* Spread the word. */
420 detach_driver_chain (port);
421
422#ifdef CONFIG_PARPORT_1284
423 /* Forget the IEEE1284.3 topology of the port. */
424 parport_daisy_fini(port);
425 for (i = 1; i < 3; i++) {
426 struct parport *slave = port->slaves[i-1];
427 if (!slave)
428 continue;
429 detach_driver_chain(slave);
430 parport_daisy_fini(slave);
431 }
432#endif
433
434 port->ops = &dead_ops;
435 spin_lock(&parportlist_lock);
436 list_del_init(&port->list);
437 for (i = 1; i < 3; i++) {
438 struct parport *slave = port->slaves[i-1];
439 if (slave)
440 list_del_init(&slave->list);
441 }
442 spin_unlock(&parportlist_lock);
443
444 mutex_unlock(®istration_lock);
445
446 parport_proc_unregister(port);
447
448 for (i = 1; i < 3; i++) {
449 struct parport *slave = port->slaves[i-1];
450 if (slave)
451 parport_put_port(slave);
452 }
453}
454
455/**
456 * parport_register_device - register a device on a parallel port
457 * @port: port to which the device is attached
458 * @name: a name to refer to the device
459 * @pf: preemption callback
460 * @kf: kick callback (wake-up)
461 * @irq_func: interrupt handler
462 * @flags: registration flags
463 * @handle: data for callback functions
464 *
465 * This function, called by parallel port device drivers,
466 * declares that a device is connected to a port, and tells the
467 * system all it needs to know.
468 *
469 * The @name is allocated by the caller and must not be
470 * deallocated until the caller calls @parport_unregister_device
471 * for that device.
472 *
473 * The preemption callback function, @pf, is called when this
474 * device driver has claimed access to the port but another
475 * device driver wants to use it. It is given @handle as its
476 * parameter, and should return zero if it is willing for the
477 * system to release the port to another driver on its behalf.
478 * If it wants to keep control of the port it should return
479 * non-zero, and no action will be taken. It is good manners for
480 * the driver to try to release the port at the earliest
481 * opportunity after its preemption callback rejects a preemption
482 * attempt. Note that if a preemption callback is happy for
483 * preemption to go ahead, there is no need to release the port;
484 * it is done automatically. This function may not block, as it
485 * may be called from interrupt context. If the device driver
486 * does not support preemption, @pf can be %NULL.
487 *
488 * The wake-up ("kick") callback function, @kf, is called when
489 * the port is available to be claimed for exclusive access; that
490 * is, parport_claim() is guaranteed to succeed when called from
491 * inside the wake-up callback function. If the driver wants to
492 * claim the port it should do so; otherwise, it need not take
493 * any action. This function may not block, as it may be called
494 * from interrupt context. If the device driver does not want to
495 * be explicitly invited to claim the port in this way, @kf can
496 * be %NULL.
497 *
498 * The interrupt handler, @irq_func, is called when an interrupt
499 * arrives from the parallel port. Note that if a device driver
500 * wants to use interrupts it should use parport_enable_irq(),
501 * and can also check the irq member of the parport structure
502 * representing the port.
503 *
504 * The parallel port (lowlevel) driver is the one that has called
505 * request_irq() and whose interrupt handler is called first.
506 * This handler does whatever needs to be done to the hardware to
507 * acknowledge the interrupt (for PC-style ports there is nothing
508 * special to be done). It then tells the IEEE 1284 code about
509 * the interrupt, which may involve reacting to an IEEE 1284
510 * event depending on the current IEEE 1284 phase. After this,
511 * it calls @irq_func. Needless to say, @irq_func will be called
512 * from interrupt context, and may not block.
513 *
514 * The %PARPORT_DEV_EXCL flag is for preventing port sharing, and
515 * so should only be used when sharing the port with other device
516 * drivers is impossible and would lead to incorrect behaviour.
517 * Use it sparingly! Normally, @flags will be zero.
518 *
519 * This function returns a pointer to a structure that represents
520 * the device on the port, or %NULL if there is not enough memory
521 * to allocate space for that structure.
522 **/
523
524struct pardevice *
525parport_register_device(struct parport *port, const char *name,
526 int (*pf)(void *), void (*kf)(void *),
527 void (*irq_func)(void *),
528 int flags, void *handle)
529{
530 struct pardevice *tmp;
531
532 if (port->physport->flags & PARPORT_FLAG_EXCL) {
533 /* An exclusive device is registered. */
534 printk (KERN_DEBUG "%s: no more devices allowed\n",
535 port->name);
536 return NULL;
537 }
538
539 if (flags & PARPORT_DEV_LURK) {
540 if (!pf || !kf) {
541 printk(KERN_INFO "%s: refused to register lurking device (%s) without callbacks\n", port->name, name);
542 return NULL;
543 }
544 }
545
546 /* We up our own module reference count, and that of the port
547 on which a device is to be registered, to ensure that
548 neither of us gets unloaded while we sleep in (e.g.)
549 kmalloc.
550 */
551 if (!try_module_get(port->ops->owner)) {
552 return NULL;
553 }
554
555 parport_get_port (port);
556
557 tmp = kmalloc(sizeof(struct pardevice), GFP_KERNEL);
558 if (tmp == NULL) {
559 printk(KERN_WARNING "%s: memory squeeze, couldn't register %s.\n", port->name, name);
560 goto out;
561 }
562
563 tmp->state = kmalloc(sizeof(struct parport_state), GFP_KERNEL);
564 if (tmp->state == NULL) {
565 printk(KERN_WARNING "%s: memory squeeze, couldn't register %s.\n", port->name, name);
566 goto out_free_pardevice;
567 }
568
569 tmp->name = name;
570 tmp->port = port;
571 tmp->daisy = -1;
572 tmp->preempt = pf;
573 tmp->wakeup = kf;
574 tmp->private = handle;
575 tmp->flags = flags;
576 tmp->irq_func = irq_func;
577 tmp->waiting = 0;
578 tmp->timeout = 5 * HZ;
579
580 /* Chain this onto the list */
581 tmp->prev = NULL;
582 /*
583 * This function must not run from an irq handler so we don' t need
584 * to clear irq on the local CPU. -arca
585 */
586 spin_lock(&port->physport->pardevice_lock);
587
588 if (flags & PARPORT_DEV_EXCL) {
589 if (port->physport->devices) {
590 spin_unlock (&port->physport->pardevice_lock);
591 printk (KERN_DEBUG
592 "%s: cannot grant exclusive access for "
593 "device %s\n", port->name, name);
594 goto out_free_all;
595 }
596 port->flags |= PARPORT_FLAG_EXCL;
597 }
598
599 tmp->next = port->physport->devices;
600 wmb(); /* Make sure that tmp->next is written before it's
601 added to the list; see comments marked 'no locking
602 required' */
603 if (port->physport->devices)
604 port->physport->devices->prev = tmp;
605 port->physport->devices = tmp;
606 spin_unlock(&port->physport->pardevice_lock);
607
608 init_waitqueue_head(&tmp->wait_q);
609 tmp->timeslice = parport_default_timeslice;
610 tmp->waitnext = tmp->waitprev = NULL;
611
612 /*
613 * This has to be run as last thing since init_state may need other
614 * pardevice fields. -arca
615 */
616 port->ops->init_state(tmp, tmp->state);
617 if (!test_and_set_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags)) {
618 port->proc_device = tmp;
619 parport_device_proc_register(tmp);
620 }
621 return tmp;
622
623 out_free_all:
624 kfree(tmp->state);
625 out_free_pardevice:
626 kfree(tmp);
627 out:
628 parport_put_port (port);
629 module_put(port->ops->owner);
630
631 return NULL;
632}
633
634/**
635 * parport_unregister_device - deregister a device on a parallel port
636 * @dev: pointer to structure representing device
637 *
638 * This undoes the effect of parport_register_device().
639 **/
640
641void parport_unregister_device(struct pardevice *dev)
642{
643 struct parport *port;
644
645#ifdef PARPORT_PARANOID
646 if (dev == NULL) {
647 printk(KERN_ERR "parport_unregister_device: passed NULL\n");
648 return;
649 }
650#endif
651
652 port = dev->port->physport;
653
654 if (port->proc_device == dev) {
655 port->proc_device = NULL;
656 clear_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags);
657 parport_device_proc_unregister(dev);
658 }
659
660 if (port->cad == dev) {
661 printk(KERN_DEBUG "%s: %s forgot to release port\n",
662 port->name, dev->name);
663 parport_release (dev);
664 }
665
666 spin_lock(&port->pardevice_lock);
667 if (dev->next)
668 dev->next->prev = dev->prev;
669 if (dev->prev)
670 dev->prev->next = dev->next;
671 else
672 port->devices = dev->next;
673
674 if (dev->flags & PARPORT_DEV_EXCL)
675 port->flags &= ~PARPORT_FLAG_EXCL;
676
677 spin_unlock(&port->pardevice_lock);
678
679 /* Make sure we haven't left any pointers around in the wait
680 * list. */
681 spin_lock_irq(&port->waitlist_lock);
682 if (dev->waitprev || dev->waitnext || port->waithead == dev) {
683 if (dev->waitprev)
684 dev->waitprev->waitnext = dev->waitnext;
685 else
686 port->waithead = dev->waitnext;
687 if (dev->waitnext)
688 dev->waitnext->waitprev = dev->waitprev;
689 else
690 port->waittail = dev->waitprev;
691 }
692 spin_unlock_irq(&port->waitlist_lock);
693
694 kfree(dev->state);
695 kfree(dev);
696
697 module_put(port->ops->owner);
698 parport_put_port (port);
699}
700
701/**
702 * parport_find_number - find a parallel port by number
703 * @number: parallel port number
704 *
705 * This returns the parallel port with the specified number, or
706 * %NULL if there is none.
707 *
708 * There is an implicit parport_get_port() done already; to throw
709 * away the reference to the port that parport_find_number()
710 * gives you, use parport_put_port().
711 */
712
713struct parport *parport_find_number (int number)
714{
715 struct parport *port, *result = NULL;
716
717 if (list_empty(&portlist))
718 get_lowlevel_driver ();
719
720 spin_lock (&parportlist_lock);
721 list_for_each_entry(port, &portlist, list) {
722 if (port->number == number) {
723 result = parport_get_port (port);
724 break;
725 }
726 }
727 spin_unlock (&parportlist_lock);
728 return result;
729}
730
731/**
732 * parport_find_base - find a parallel port by base address
733 * @base: base I/O address
734 *
735 * This returns the parallel port with the specified base
736 * address, or %NULL if there is none.
737 *
738 * There is an implicit parport_get_port() done already; to throw
739 * away the reference to the port that parport_find_base()
740 * gives you, use parport_put_port().
741 */
742
743struct parport *parport_find_base (unsigned long base)
744{
745 struct parport *port, *result = NULL;
746
747 if (list_empty(&portlist))
748 get_lowlevel_driver ();
749
750 spin_lock (&parportlist_lock);
751 list_for_each_entry(port, &portlist, list) {
752 if (port->base == base) {
753 result = parport_get_port (port);
754 break;
755 }
756 }
757 spin_unlock (&parportlist_lock);
758 return result;
759}
760
761/**
762 * parport_claim - claim access to a parallel port device
763 * @dev: pointer to structure representing a device on the port
764 *
765 * This function will not block and so can be used from interrupt
766 * context. If parport_claim() succeeds in claiming access to
767 * the port it returns zero and the port is available to use. It
768 * may fail (returning non-zero) if the port is in use by another
769 * driver and that driver is not willing to relinquish control of
770 * the port.
771 **/
772
773int parport_claim(struct pardevice *dev)
774{
775 struct pardevice *oldcad;
776 struct parport *port = dev->port->physport;
777 unsigned long flags;
778
779 if (port->cad == dev) {
780 printk(KERN_INFO "%s: %s already owner\n",
781 dev->port->name,dev->name);
782 return 0;
783 }
784
785 /* Preempt any current device */
786 write_lock_irqsave (&port->cad_lock, flags);
787 if ((oldcad = port->cad) != NULL) {
788 if (oldcad->preempt) {
789 if (oldcad->preempt(oldcad->private))
790 goto blocked;
791 port->ops->save_state(port, dev->state);
792 } else
793 goto blocked;
794
795 if (port->cad != oldcad) {
796 /* I think we'll actually deadlock rather than
797 get here, but just in case.. */
798 printk(KERN_WARNING
799 "%s: %s released port when preempted!\n",
800 port->name, oldcad->name);
801 if (port->cad)
802 goto blocked;
803 }
804 }
805
806 /* Can't fail from now on, so mark ourselves as no longer waiting. */
807 if (dev->waiting & 1) {
808 dev->waiting = 0;
809
810 /* Take ourselves out of the wait list again. */
811 spin_lock_irq (&port->waitlist_lock);
812 if (dev->waitprev)
813 dev->waitprev->waitnext = dev->waitnext;
814 else
815 port->waithead = dev->waitnext;
816 if (dev->waitnext)
817 dev->waitnext->waitprev = dev->waitprev;
818 else
819 port->waittail = dev->waitprev;
820 spin_unlock_irq (&port->waitlist_lock);
821 dev->waitprev = dev->waitnext = NULL;
822 }
823
824 /* Now we do the change of devices */
825 port->cad = dev;
826
827#ifdef CONFIG_PARPORT_1284
828 /* If it's a mux port, select it. */
829 if (dev->port->muxport >= 0) {
830 /* FIXME */
831 port->muxsel = dev->port->muxport;
832 }
833
834 /* If it's a daisy chain device, select it. */
835 if (dev->daisy >= 0) {
836 /* This could be lazier. */
837 if (!parport_daisy_select (port, dev->daisy,
838 IEEE1284_MODE_COMPAT))
839 port->daisy = dev->daisy;
840 }
841#endif /* IEEE1284.3 support */
842
843 /* Restore control registers */
844 port->ops->restore_state(port, dev->state);
845 write_unlock_irqrestore(&port->cad_lock, flags);
846 dev->time = jiffies;
847 return 0;
848
849blocked:
850 /* If this is the first time we tried to claim the port, register an
851 interest. This is only allowed for devices sleeping in
852 parport_claim_or_block(), or those with a wakeup function. */
853
854 /* The cad_lock is still held for writing here */
855 if (dev->waiting & 2 || dev->wakeup) {
856 spin_lock (&port->waitlist_lock);
857 if (test_and_set_bit(0, &dev->waiting) == 0) {
858 /* First add ourselves to the end of the wait list. */
859 dev->waitnext = NULL;
860 dev->waitprev = port->waittail;
861 if (port->waittail) {
862 port->waittail->waitnext = dev;
863 port->waittail = dev;
864 } else
865 port->waithead = port->waittail = dev;
866 }
867 spin_unlock (&port->waitlist_lock);
868 }
869 write_unlock_irqrestore (&port->cad_lock, flags);
870 return -EAGAIN;
871}
872
873/**
874 * parport_claim_or_block - claim access to a parallel port device
875 * @dev: pointer to structure representing a device on the port
876 *
877 * This behaves like parport_claim(), but will block if necessary
878 * to wait for the port to be free. A return value of 1
879 * indicates that it slept; 0 means that it succeeded without
880 * needing to sleep. A negative error code indicates failure.
881 **/
882
883int parport_claim_or_block(struct pardevice *dev)
884{
885 int r;
886
887 /* Signal to parport_claim() that we can wait even without a
888 wakeup function. */
889 dev->waiting = 2;
890
891 /* Try to claim the port. If this fails, we need to sleep. */
892 r = parport_claim(dev);
893 if (r == -EAGAIN) {
894#ifdef PARPORT_DEBUG_SHARING
895 printk(KERN_DEBUG "%s: parport_claim() returned -EAGAIN\n", dev->name);
896#endif
897 /*
898 * FIXME!!! Use the proper locking for dev->waiting,
899 * and make this use the "wait_event_interruptible()"
900 * interfaces. The cli/sti that used to be here
901 * did nothing.
902 *
903 * See also parport_release()
904 */
905
906 /* If dev->waiting is clear now, an interrupt
907 gave us the port and we would deadlock if we slept. */
908 if (dev->waiting) {
909 interruptible_sleep_on (&dev->wait_q);
910 if (signal_pending (current)) {
911 return -EINTR;
912 }
913 r = 1;
914 } else {
915 r = 0;
916#ifdef PARPORT_DEBUG_SHARING
917 printk(KERN_DEBUG "%s: didn't sleep in parport_claim_or_block()\n",
918 dev->name);
919#endif
920 }
921
922#ifdef PARPORT_DEBUG_SHARING
923 if (dev->port->physport->cad != dev)
924 printk(KERN_DEBUG "%s: exiting parport_claim_or_block "
925 "but %s owns port!\n", dev->name,
926 dev->port->physport->cad ?
927 dev->port->physport->cad->name:"nobody");
928#endif
929 }
930 dev->waiting = 0;
931 return r;
932}
933
934/**
935 * parport_release - give up access to a parallel port device
936 * @dev: pointer to structure representing parallel port device
937 *
938 * This function cannot fail, but it should not be called without
939 * the port claimed. Similarly, if the port is already claimed
940 * you should not try claiming it again.
941 **/
942
943void parport_release(struct pardevice *dev)
944{
945 struct parport *port = dev->port->physport;
946 struct pardevice *pd;
947 unsigned long flags;
948
949 /* Make sure that dev is the current device */
950 write_lock_irqsave(&port->cad_lock, flags);
951 if (port->cad != dev) {
952 write_unlock_irqrestore (&port->cad_lock, flags);
953 printk(KERN_WARNING "%s: %s tried to release parport "
954 "when not owner\n", port->name, dev->name);
955 return;
956 }
957
958#ifdef CONFIG_PARPORT_1284
959 /* If this is on a mux port, deselect it. */
960 if (dev->port->muxport >= 0) {
961 /* FIXME */
962 port->muxsel = -1;
963 }
964
965 /* If this is a daisy device, deselect it. */
966 if (dev->daisy >= 0) {
967 parport_daisy_deselect_all (port);
968 port->daisy = -1;
969 }
970#endif
971
972 port->cad = NULL;
973 write_unlock_irqrestore(&port->cad_lock, flags);
974
975 /* Save control registers */
976 port->ops->save_state(port, dev->state);
977
978 /* If anybody is waiting, find out who's been there longest and
979 then wake them up. (Note: no locking required) */
980 /* !!! LOCKING IS NEEDED HERE */
981 for (pd = port->waithead; pd; pd = pd->waitnext) {
982 if (pd->waiting & 2) { /* sleeping in claim_or_block */
983 parport_claim(pd);
984 if (waitqueue_active(&pd->wait_q))
985 wake_up_interruptible(&pd->wait_q);
986 return;
987 } else if (pd->wakeup) {
988 pd->wakeup(pd->private);
989 if (dev->port->cad) /* racy but no matter */
990 return;
991 } else {
992 printk(KERN_ERR "%s: don't know how to wake %s\n", port->name, pd->name);
993 }
994 }
995
996 /* Nobody was waiting, so walk the list to see if anyone is
997 interested in being woken up. (Note: no locking required) */
998 /* !!! LOCKING IS NEEDED HERE */
999 for (pd = port->devices; (port->cad == NULL) && pd; pd = pd->next) {
1000 if (pd->wakeup && pd != dev)
1001 pd->wakeup(pd->private);
1002 }
1003}
1004
1005irqreturn_t parport_irq_handler(int irq, void *dev_id)
1006{
1007 struct parport *port = dev_id;
1008
1009 parport_generic_irq(port);
1010
1011 return IRQ_HANDLED;
1012}
1013
1014/* Exported symbols for modules. */
1015
1016EXPORT_SYMBOL(parport_claim);
1017EXPORT_SYMBOL(parport_claim_or_block);
1018EXPORT_SYMBOL(parport_release);
1019EXPORT_SYMBOL(parport_register_port);
1020EXPORT_SYMBOL(parport_announce_port);
1021EXPORT_SYMBOL(parport_remove_port);
1022EXPORT_SYMBOL(parport_register_driver);
1023EXPORT_SYMBOL(parport_unregister_driver);
1024EXPORT_SYMBOL(parport_register_device);
1025EXPORT_SYMBOL(parport_unregister_device);
1026EXPORT_SYMBOL(parport_get_port);
1027EXPORT_SYMBOL(parport_put_port);
1028EXPORT_SYMBOL(parport_find_number);
1029EXPORT_SYMBOL(parport_find_base);
1030EXPORT_SYMBOL(parport_irq_handler);
1031
1032MODULE_LICENSE("GPL");
1/*
2 * Parallel-port resource manager code.
3 *
4 * Authors: David Campbell <campbell@tirian.che.curtin.edu.au>
5 * Tim Waugh <tim@cyberelk.demon.co.uk>
6 * Jose Renau <renau@acm.org>
7 * Philip Blundell <philb@gnu.org>
8 * Andrea Arcangeli
9 *
10 * based on work by Grant Guenther <grant@torque.net>
11 * and Philip Blundell
12 *
13 * Any part of this program may be used in documents licensed under
14 * the GNU Free Documentation License, Version 1.1 or any later version
15 * published by the Free Software Foundation.
16 */
17
18#undef PARPORT_DEBUG_SHARING /* undef for production */
19
20#include <linux/module.h>
21#include <linux/string.h>
22#include <linux/threads.h>
23#include <linux/parport.h>
24#include <linux/delay.h>
25#include <linux/errno.h>
26#include <linux/interrupt.h>
27#include <linux/ioport.h>
28#include <linux/kernel.h>
29#include <linux/slab.h>
30#include <linux/sched.h>
31#include <linux/kmod.h>
32#include <linux/device.h>
33
34#include <linux/spinlock.h>
35#include <linux/mutex.h>
36#include <asm/irq.h>
37
38#undef PARPORT_PARANOID
39
40#define PARPORT_DEFAULT_TIMESLICE (HZ/5)
41
42unsigned long parport_default_timeslice = PARPORT_DEFAULT_TIMESLICE;
43int parport_default_spintime = DEFAULT_SPIN_TIME;
44
45static LIST_HEAD(portlist);
46static DEFINE_SPINLOCK(parportlist_lock);
47
48/* list of all allocated ports, sorted by ->number */
49static LIST_HEAD(all_ports);
50static DEFINE_SPINLOCK(full_list_lock);
51
52static LIST_HEAD(drivers);
53
54static DEFINE_MUTEX(registration_lock);
55
56/* What you can do to a port that's gone away.. */
57static void dead_write_lines(struct parport *p, unsigned char b){}
58static unsigned char dead_read_lines(struct parport *p) { return 0; }
59static unsigned char dead_frob_lines(struct parport *p, unsigned char b,
60 unsigned char c) { return 0; }
61static void dead_onearg(struct parport *p){}
62static void dead_initstate(struct pardevice *d, struct parport_state *s) { }
63static void dead_state(struct parport *p, struct parport_state *s) { }
64static size_t dead_write(struct parport *p, const void *b, size_t l, int f)
65{ return 0; }
66static size_t dead_read(struct parport *p, void *b, size_t l, int f)
67{ return 0; }
68static struct parport_operations dead_ops = {
69 .write_data = dead_write_lines, /* data */
70 .read_data = dead_read_lines,
71
72 .write_control = dead_write_lines, /* control */
73 .read_control = dead_read_lines,
74 .frob_control = dead_frob_lines,
75
76 .read_status = dead_read_lines, /* status */
77
78 .enable_irq = dead_onearg, /* enable_irq */
79 .disable_irq = dead_onearg, /* disable_irq */
80
81 .data_forward = dead_onearg, /* data_forward */
82 .data_reverse = dead_onearg, /* data_reverse */
83
84 .init_state = dead_initstate, /* init_state */
85 .save_state = dead_state,
86 .restore_state = dead_state,
87
88 .epp_write_data = dead_write, /* epp */
89 .epp_read_data = dead_read,
90 .epp_write_addr = dead_write,
91 .epp_read_addr = dead_read,
92
93 .ecp_write_data = dead_write, /* ecp */
94 .ecp_read_data = dead_read,
95 .ecp_write_addr = dead_write,
96
97 .compat_write_data = dead_write, /* compat */
98 .nibble_read_data = dead_read, /* nibble */
99 .byte_read_data = dead_read, /* byte */
100
101 .owner = NULL,
102};
103
104static struct device_type parport_device_type = {
105 .name = "parport",
106};
107
108static int is_parport(struct device *dev)
109{
110 return dev->type == &parport_device_type;
111}
112
113static int parport_probe(struct device *dev)
114{
115 struct parport_driver *drv;
116
117 if (is_parport(dev))
118 return -ENODEV;
119
120 drv = to_parport_driver(dev->driver);
121 if (!drv->probe) {
122 /* if driver has not defined a custom probe */
123 struct pardevice *par_dev = to_pardevice(dev);
124
125 if (strcmp(par_dev->name, drv->name))
126 return -ENODEV;
127 return 0;
128 }
129 /* if driver defined its own probe */
130 return drv->probe(to_pardevice(dev));
131}
132
133static struct bus_type parport_bus_type = {
134 .name = "parport",
135 .probe = parport_probe,
136};
137
138int parport_bus_init(void)
139{
140 return bus_register(&parport_bus_type);
141}
142
143void parport_bus_exit(void)
144{
145 bus_unregister(&parport_bus_type);
146}
147
148/*
149 * iterates through all the drivers registered with the bus and sends the port
150 * details to the match_port callback of the driver, so that the driver can
151 * know about the new port that just registered with the bus and decide if it
152 * wants to use this new port.
153 */
154static int driver_check(struct device_driver *dev_drv, void *_port)
155{
156 struct parport *port = _port;
157 struct parport_driver *drv = to_parport_driver(dev_drv);
158
159 if (drv->match_port)
160 drv->match_port(port);
161 return 0;
162}
163
164/* Call attach(port) for each registered driver. */
165static void attach_driver_chain(struct parport *port)
166{
167 /* caller has exclusive registration_lock */
168 struct parport_driver *drv;
169
170 list_for_each_entry(drv, &drivers, list)
171 drv->attach(port);
172
173 /*
174 * call the driver_check function of the drivers registered in
175 * new device model
176 */
177
178 bus_for_each_drv(&parport_bus_type, NULL, port, driver_check);
179}
180
181static int driver_detach(struct device_driver *_drv, void *_port)
182{
183 struct parport *port = _port;
184 struct parport_driver *drv = to_parport_driver(_drv);
185
186 if (drv->detach)
187 drv->detach(port);
188 return 0;
189}
190
191/* Call detach(port) for each registered driver. */
192static void detach_driver_chain(struct parport *port)
193{
194 struct parport_driver *drv;
195 /* caller has exclusive registration_lock */
196 list_for_each_entry(drv, &drivers, list)
197 drv->detach(port);
198
199 /*
200 * call the detach function of the drivers registered in
201 * new device model
202 */
203
204 bus_for_each_drv(&parport_bus_type, NULL, port, driver_detach);
205}
206
207/* Ask kmod for some lowlevel drivers. */
208static void get_lowlevel_driver(void)
209{
210 /*
211 * There is no actual module called this: you should set
212 * up an alias for modutils.
213 */
214 request_module("parport_lowlevel");
215}
216
217/*
218 * iterates through all the devices connected to the bus and sends the device
219 * details to the match_port callback of the driver, so that the driver can
220 * know what are all the ports that are connected to the bus and choose the
221 * port to which it wants to register its device.
222 */
223static int port_check(struct device *dev, void *dev_drv)
224{
225 struct parport_driver *drv = dev_drv;
226
227 /* only send ports, do not send other devices connected to bus */
228 if (is_parport(dev))
229 drv->match_port(to_parport_dev(dev));
230 return 0;
231}
232
233/**
234 * parport_register_driver - register a parallel port device driver
235 * @drv: structure describing the driver
236 * @owner: owner module of drv
237 * @mod_name: module name string
238 *
239 * This can be called by a parallel port device driver in order
240 * to receive notifications about ports being found in the
241 * system, as well as ports no longer available.
242 *
243 * If devmodel is true then the new device model is used
244 * for registration.
245 *
246 * The @drv structure is allocated by the caller and must not be
247 * deallocated until after calling parport_unregister_driver().
248 *
249 * If using the non device model:
250 * The driver's attach() function may block. The port that
251 * attach() is given will be valid for the duration of the
252 * callback, but if the driver wants to take a copy of the
253 * pointer it must call parport_get_port() to do so. Calling
254 * parport_register_device() on that port will do this for you.
255 *
256 * The driver's detach() function may block. The port that
257 * detach() is given will be valid for the duration of the
258 * callback, but if the driver wants to take a copy of the
259 * pointer it must call parport_get_port() to do so.
260 *
261 *
262 * Returns 0 on success. The non device model will always succeeds.
263 * but the new device model can fail and will return the error code.
264 **/
265
266int __parport_register_driver(struct parport_driver *drv, struct module *owner,
267 const char *mod_name)
268{
269 if (list_empty(&portlist))
270 get_lowlevel_driver();
271
272 if (drv->devmodel) {
273 /* using device model */
274 int ret;
275
276 /* initialize common driver fields */
277 drv->driver.name = drv->name;
278 drv->driver.bus = &parport_bus_type;
279 drv->driver.owner = owner;
280 drv->driver.mod_name = mod_name;
281 ret = driver_register(&drv->driver);
282 if (ret)
283 return ret;
284
285 mutex_lock(®istration_lock);
286 if (drv->match_port)
287 bus_for_each_dev(&parport_bus_type, NULL, drv,
288 port_check);
289 mutex_unlock(®istration_lock);
290 } else {
291 struct parport *port;
292
293 drv->devmodel = false;
294
295 mutex_lock(®istration_lock);
296 list_for_each_entry(port, &portlist, list)
297 drv->attach(port);
298 list_add(&drv->list, &drivers);
299 mutex_unlock(®istration_lock);
300 }
301
302 return 0;
303}
304EXPORT_SYMBOL(__parport_register_driver);
305
306static int port_detach(struct device *dev, void *_drv)
307{
308 struct parport_driver *drv = _drv;
309
310 if (is_parport(dev) && drv->detach)
311 drv->detach(to_parport_dev(dev));
312
313 return 0;
314}
315
316/**
317 * parport_unregister_driver - deregister a parallel port device driver
318 * @drv: structure describing the driver that was given to
319 * parport_register_driver()
320 *
321 * This should be called by a parallel port device driver that
322 * has registered itself using parport_register_driver() when it
323 * is about to be unloaded.
324 *
325 * When it returns, the driver's attach() routine will no longer
326 * be called, and for each port that attach() was called for, the
327 * detach() routine will have been called.
328 *
329 * All the driver's attach() and detach() calls are guaranteed to have
330 * finished by the time this function returns.
331 **/
332
333void parport_unregister_driver(struct parport_driver *drv)
334{
335 struct parport *port;
336
337 mutex_lock(®istration_lock);
338 if (drv->devmodel) {
339 bus_for_each_dev(&parport_bus_type, NULL, drv, port_detach);
340 driver_unregister(&drv->driver);
341 } else {
342 list_del_init(&drv->list);
343 list_for_each_entry(port, &portlist, list)
344 drv->detach(port);
345 }
346 mutex_unlock(®istration_lock);
347}
348EXPORT_SYMBOL(parport_unregister_driver);
349
350static void free_port(struct device *dev)
351{
352 int d;
353 struct parport *port = to_parport_dev(dev);
354
355 spin_lock(&full_list_lock);
356 list_del(&port->full_list);
357 spin_unlock(&full_list_lock);
358 for (d = 0; d < 5; d++) {
359 kfree(port->probe_info[d].class_name);
360 kfree(port->probe_info[d].mfr);
361 kfree(port->probe_info[d].model);
362 kfree(port->probe_info[d].cmdset);
363 kfree(port->probe_info[d].description);
364 }
365
366 kfree(port->name);
367 kfree(port);
368}
369
370/**
371 * parport_get_port - increment a port's reference count
372 * @port: the port
373 *
374 * This ensures that a struct parport pointer remains valid
375 * until the matching parport_put_port() call.
376 **/
377
378struct parport *parport_get_port(struct parport *port)
379{
380 struct device *dev = get_device(&port->bus_dev);
381
382 return to_parport_dev(dev);
383}
384EXPORT_SYMBOL(parport_get_port);
385
386void parport_del_port(struct parport *port)
387{
388 device_unregister(&port->bus_dev);
389}
390EXPORT_SYMBOL(parport_del_port);
391
392/**
393 * parport_put_port - decrement a port's reference count
394 * @port: the port
395 *
396 * This should be called once for each call to parport_get_port(),
397 * once the port is no longer needed. When the reference count reaches
398 * zero (port is no longer used), free_port is called.
399 **/
400
401void parport_put_port(struct parport *port)
402{
403 put_device(&port->bus_dev);
404}
405EXPORT_SYMBOL(parport_put_port);
406
407/**
408 * parport_register_port - register a parallel port
409 * @base: base I/O address
410 * @irq: IRQ line
411 * @dma: DMA channel
412 * @ops: pointer to the port driver's port operations structure
413 *
414 * When a parallel port (lowlevel) driver finds a port that
415 * should be made available to parallel port device drivers, it
416 * should call parport_register_port(). The @base, @irq, and
417 * @dma parameters are for the convenience of port drivers, and
418 * for ports where they aren't meaningful needn't be set to
419 * anything special. They can be altered afterwards by adjusting
420 * the relevant members of the parport structure that is returned
421 * and represents the port. They should not be tampered with
422 * after calling parport_announce_port, however.
423 *
424 * If there are parallel port device drivers in the system that
425 * have registered themselves using parport_register_driver(),
426 * they are not told about the port at this time; that is done by
427 * parport_announce_port().
428 *
429 * The @ops structure is allocated by the caller, and must not be
430 * deallocated before calling parport_remove_port().
431 *
432 * If there is no memory to allocate a new parport structure,
433 * this function will return %NULL.
434 **/
435
436struct parport *parport_register_port(unsigned long base, int irq, int dma,
437 struct parport_operations *ops)
438{
439 struct list_head *l;
440 struct parport *tmp;
441 int num;
442 int device;
443 char *name;
444 int ret;
445
446 tmp = kzalloc(sizeof(struct parport), GFP_KERNEL);
447 if (!tmp)
448 return NULL;
449
450 /* Init our structure */
451 tmp->base = base;
452 tmp->irq = irq;
453 tmp->dma = dma;
454 tmp->muxport = tmp->daisy = tmp->muxsel = -1;
455 tmp->modes = 0;
456 INIT_LIST_HEAD(&tmp->list);
457 tmp->devices = tmp->cad = NULL;
458 tmp->flags = 0;
459 tmp->ops = ops;
460 tmp->physport = tmp;
461 memset(tmp->probe_info, 0, 5 * sizeof(struct parport_device_info));
462 rwlock_init(&tmp->cad_lock);
463 spin_lock_init(&tmp->waitlist_lock);
464 spin_lock_init(&tmp->pardevice_lock);
465 tmp->ieee1284.mode = IEEE1284_MODE_COMPAT;
466 tmp->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
467 sema_init(&tmp->ieee1284.irq, 0);
468 tmp->spintime = parport_default_spintime;
469 atomic_set(&tmp->ref_count, 1);
470 INIT_LIST_HEAD(&tmp->full_list);
471
472 name = kmalloc(15, GFP_KERNEL);
473 if (!name) {
474 kfree(tmp);
475 return NULL;
476 }
477 /* Search for the lowest free parport number. */
478
479 spin_lock(&full_list_lock);
480 for (l = all_ports.next, num = 0; l != &all_ports; l = l->next, num++) {
481 struct parport *p = list_entry(l, struct parport, full_list);
482 if (p->number != num)
483 break;
484 }
485 tmp->portnum = tmp->number = num;
486 list_add_tail(&tmp->full_list, l);
487 spin_unlock(&full_list_lock);
488
489 /*
490 * Now that the portnum is known finish doing the Init.
491 */
492 sprintf(name, "parport%d", tmp->portnum = tmp->number);
493 tmp->name = name;
494 tmp->bus_dev.bus = &parport_bus_type;
495 tmp->bus_dev.release = free_port;
496 dev_set_name(&tmp->bus_dev, name);
497 tmp->bus_dev.type = &parport_device_type;
498
499 for (device = 0; device < 5; device++)
500 /* assume the worst */
501 tmp->probe_info[device].class = PARPORT_CLASS_LEGACY;
502
503 tmp->waithead = tmp->waittail = NULL;
504
505 ret = device_register(&tmp->bus_dev);
506 if (ret) {
507 put_device(&tmp->bus_dev);
508 return NULL;
509 }
510
511 return tmp;
512}
513EXPORT_SYMBOL(parport_register_port);
514
515/**
516 * parport_announce_port - tell device drivers about a parallel port
517 * @port: parallel port to announce
518 *
519 * After a port driver has registered a parallel port with
520 * parport_register_port, and performed any necessary
521 * initialisation or adjustments, it should call
522 * parport_announce_port() in order to notify all device drivers
523 * that have called parport_register_driver(). Their attach()
524 * functions will be called, with @port as the parameter.
525 **/
526
527void parport_announce_port(struct parport *port)
528{
529 int i;
530
531#ifdef CONFIG_PARPORT_1284
532 /* Analyse the IEEE1284.3 topology of the port. */
533 parport_daisy_init(port);
534#endif
535
536 if (!port->dev)
537 printk(KERN_WARNING "%s: fix this legacy no-device port driver!\n",
538 port->name);
539
540 parport_proc_register(port);
541 mutex_lock(®istration_lock);
542 spin_lock_irq(&parportlist_lock);
543 list_add_tail(&port->list, &portlist);
544 for (i = 1; i < 3; i++) {
545 struct parport *slave = port->slaves[i-1];
546 if (slave)
547 list_add_tail(&slave->list, &portlist);
548 }
549 spin_unlock_irq(&parportlist_lock);
550
551 /* Let drivers know that new port(s) has arrived. */
552 attach_driver_chain(port);
553 for (i = 1; i < 3; i++) {
554 struct parport *slave = port->slaves[i-1];
555 if (slave)
556 attach_driver_chain(slave);
557 }
558 mutex_unlock(®istration_lock);
559}
560EXPORT_SYMBOL(parport_announce_port);
561
562/**
563 * parport_remove_port - deregister a parallel port
564 * @port: parallel port to deregister
565 *
566 * When a parallel port driver is forcibly unloaded, or a
567 * parallel port becomes inaccessible, the port driver must call
568 * this function in order to deal with device drivers that still
569 * want to use it.
570 *
571 * The parport structure associated with the port has its
572 * operations structure replaced with one containing 'null'
573 * operations that return errors or just don't do anything.
574 *
575 * Any drivers that have registered themselves using
576 * parport_register_driver() are notified that the port is no
577 * longer accessible by having their detach() routines called
578 * with @port as the parameter.
579 **/
580
581void parport_remove_port(struct parport *port)
582{
583 int i;
584
585 mutex_lock(®istration_lock);
586
587 /* Spread the word. */
588 detach_driver_chain(port);
589
590#ifdef CONFIG_PARPORT_1284
591 /* Forget the IEEE1284.3 topology of the port. */
592 parport_daisy_fini(port);
593 for (i = 1; i < 3; i++) {
594 struct parport *slave = port->slaves[i-1];
595 if (!slave)
596 continue;
597 detach_driver_chain(slave);
598 parport_daisy_fini(slave);
599 }
600#endif
601
602 port->ops = &dead_ops;
603 spin_lock(&parportlist_lock);
604 list_del_init(&port->list);
605 for (i = 1; i < 3; i++) {
606 struct parport *slave = port->slaves[i-1];
607 if (slave)
608 list_del_init(&slave->list);
609 }
610 spin_unlock(&parportlist_lock);
611
612 mutex_unlock(®istration_lock);
613
614 parport_proc_unregister(port);
615
616 for (i = 1; i < 3; i++) {
617 struct parport *slave = port->slaves[i-1];
618 if (slave)
619 parport_put_port(slave);
620 }
621}
622EXPORT_SYMBOL(parport_remove_port);
623
624/**
625 * parport_register_device - register a device on a parallel port
626 * @port: port to which the device is attached
627 * @name: a name to refer to the device
628 * @pf: preemption callback
629 * @kf: kick callback (wake-up)
630 * @irq_func: interrupt handler
631 * @flags: registration flags
632 * @handle: data for callback functions
633 *
634 * This function, called by parallel port device drivers,
635 * declares that a device is connected to a port, and tells the
636 * system all it needs to know.
637 *
638 * The @name is allocated by the caller and must not be
639 * deallocated until the caller calls @parport_unregister_device
640 * for that device.
641 *
642 * The preemption callback function, @pf, is called when this
643 * device driver has claimed access to the port but another
644 * device driver wants to use it. It is given @handle as its
645 * parameter, and should return zero if it is willing for the
646 * system to release the port to another driver on its behalf.
647 * If it wants to keep control of the port it should return
648 * non-zero, and no action will be taken. It is good manners for
649 * the driver to try to release the port at the earliest
650 * opportunity after its preemption callback rejects a preemption
651 * attempt. Note that if a preemption callback is happy for
652 * preemption to go ahead, there is no need to release the port;
653 * it is done automatically. This function may not block, as it
654 * may be called from interrupt context. If the device driver
655 * does not support preemption, @pf can be %NULL.
656 *
657 * The wake-up ("kick") callback function, @kf, is called when
658 * the port is available to be claimed for exclusive access; that
659 * is, parport_claim() is guaranteed to succeed when called from
660 * inside the wake-up callback function. If the driver wants to
661 * claim the port it should do so; otherwise, it need not take
662 * any action. This function may not block, as it may be called
663 * from interrupt context. If the device driver does not want to
664 * be explicitly invited to claim the port in this way, @kf can
665 * be %NULL.
666 *
667 * The interrupt handler, @irq_func, is called when an interrupt
668 * arrives from the parallel port. Note that if a device driver
669 * wants to use interrupts it should use parport_enable_irq(),
670 * and can also check the irq member of the parport structure
671 * representing the port.
672 *
673 * The parallel port (lowlevel) driver is the one that has called
674 * request_irq() and whose interrupt handler is called first.
675 * This handler does whatever needs to be done to the hardware to
676 * acknowledge the interrupt (for PC-style ports there is nothing
677 * special to be done). It then tells the IEEE 1284 code about
678 * the interrupt, which may involve reacting to an IEEE 1284
679 * event depending on the current IEEE 1284 phase. After this,
680 * it calls @irq_func. Needless to say, @irq_func will be called
681 * from interrupt context, and may not block.
682 *
683 * The %PARPORT_DEV_EXCL flag is for preventing port sharing, and
684 * so should only be used when sharing the port with other device
685 * drivers is impossible and would lead to incorrect behaviour.
686 * Use it sparingly! Normally, @flags will be zero.
687 *
688 * This function returns a pointer to a structure that represents
689 * the device on the port, or %NULL if there is not enough memory
690 * to allocate space for that structure.
691 **/
692
693struct pardevice *
694parport_register_device(struct parport *port, const char *name,
695 int (*pf)(void *), void (*kf)(void *),
696 void (*irq_func)(void *),
697 int flags, void *handle)
698{
699 struct pardevice *tmp;
700
701 if (port->physport->flags & PARPORT_FLAG_EXCL) {
702 /* An exclusive device is registered. */
703 printk(KERN_DEBUG "%s: no more devices allowed\n",
704 port->name);
705 return NULL;
706 }
707
708 if (flags & PARPORT_DEV_LURK) {
709 if (!pf || !kf) {
710 printk(KERN_INFO "%s: refused to register lurking device (%s) without callbacks\n", port->name, name);
711 return NULL;
712 }
713 }
714
715 if (flags & PARPORT_DEV_EXCL) {
716 if (port->physport->devices) {
717 /*
718 * If a device is already registered and this new
719 * device wants exclusive access, then no need to
720 * continue as we can not grant exclusive access to
721 * this device.
722 */
723 pr_err("%s: cannot grant exclusive access for device %s\n",
724 port->name, name);
725 return NULL;
726 }
727 }
728
729 /*
730 * We up our own module reference count, and that of the port
731 * on which a device is to be registered, to ensure that
732 * neither of us gets unloaded while we sleep in (e.g.)
733 * kmalloc.
734 */
735 if (!try_module_get(port->ops->owner))
736 return NULL;
737
738 parport_get_port(port);
739
740 tmp = kmalloc(sizeof(struct pardevice), GFP_KERNEL);
741 if (!tmp)
742 goto out;
743
744 tmp->state = kmalloc(sizeof(struct parport_state), GFP_KERNEL);
745 if (!tmp->state)
746 goto out_free_pardevice;
747
748 tmp->name = name;
749 tmp->port = port;
750 tmp->daisy = -1;
751 tmp->preempt = pf;
752 tmp->wakeup = kf;
753 tmp->private = handle;
754 tmp->flags = flags;
755 tmp->irq_func = irq_func;
756 tmp->waiting = 0;
757 tmp->timeout = 5 * HZ;
758 tmp->devmodel = false;
759
760 /* Chain this onto the list */
761 tmp->prev = NULL;
762 /*
763 * This function must not run from an irq handler so we don' t need
764 * to clear irq on the local CPU. -arca
765 */
766 spin_lock(&port->physport->pardevice_lock);
767
768 if (flags & PARPORT_DEV_EXCL) {
769 if (port->physport->devices) {
770 spin_unlock(&port->physport->pardevice_lock);
771 printk(KERN_DEBUG
772 "%s: cannot grant exclusive access for device %s\n",
773 port->name, name);
774 goto out_free_all;
775 }
776 port->flags |= PARPORT_FLAG_EXCL;
777 }
778
779 tmp->next = port->physport->devices;
780 wmb(); /*
781 * Make sure that tmp->next is written before it's
782 * added to the list; see comments marked 'no locking
783 * required'
784 */
785 if (port->physport->devices)
786 port->physport->devices->prev = tmp;
787 port->physport->devices = tmp;
788 spin_unlock(&port->physport->pardevice_lock);
789
790 init_waitqueue_head(&tmp->wait_q);
791 tmp->timeslice = parport_default_timeslice;
792 tmp->waitnext = tmp->waitprev = NULL;
793
794 /*
795 * This has to be run as last thing since init_state may need other
796 * pardevice fields. -arca
797 */
798 port->ops->init_state(tmp, tmp->state);
799 if (!test_and_set_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags)) {
800 port->proc_device = tmp;
801 parport_device_proc_register(tmp);
802 }
803 return tmp;
804
805 out_free_all:
806 kfree(tmp->state);
807 out_free_pardevice:
808 kfree(tmp);
809 out:
810 parport_put_port(port);
811 module_put(port->ops->owner);
812
813 return NULL;
814}
815EXPORT_SYMBOL(parport_register_device);
816
817static void free_pardevice(struct device *dev)
818{
819 struct pardevice *par_dev = to_pardevice(dev);
820
821 kfree(par_dev->name);
822 kfree(par_dev);
823}
824
825struct pardevice *
826parport_register_dev_model(struct parport *port, const char *name,
827 const struct pardev_cb *par_dev_cb, int id)
828{
829 struct pardevice *par_dev;
830 int ret;
831 char *devname;
832
833 if (port->physport->flags & PARPORT_FLAG_EXCL) {
834 /* An exclusive device is registered. */
835 pr_err("%s: no more devices allowed\n", port->name);
836 return NULL;
837 }
838
839 if (par_dev_cb->flags & PARPORT_DEV_LURK) {
840 if (!par_dev_cb->preempt || !par_dev_cb->wakeup) {
841 pr_info("%s: refused to register lurking device (%s) without callbacks\n",
842 port->name, name);
843 return NULL;
844 }
845 }
846
847 if (par_dev_cb->flags & PARPORT_DEV_EXCL) {
848 if (port->physport->devices) {
849 /*
850 * If a device is already registered and this new
851 * device wants exclusive access, then no need to
852 * continue as we can not grant exclusive access to
853 * this device.
854 */
855 pr_err("%s: cannot grant exclusive access for device %s\n",
856 port->name, name);
857 return NULL;
858 }
859 }
860
861 if (!try_module_get(port->ops->owner))
862 return NULL;
863
864 parport_get_port(port);
865
866 par_dev = kzalloc(sizeof(*par_dev), GFP_KERNEL);
867 if (!par_dev)
868 goto err_put_port;
869
870 par_dev->state = kzalloc(sizeof(*par_dev->state), GFP_KERNEL);
871 if (!par_dev->state)
872 goto err_put_par_dev;
873
874 devname = kstrdup(name, GFP_KERNEL);
875 if (!devname)
876 goto err_free_par_dev;
877
878 par_dev->name = devname;
879 par_dev->port = port;
880 par_dev->daisy = -1;
881 par_dev->preempt = par_dev_cb->preempt;
882 par_dev->wakeup = par_dev_cb->wakeup;
883 par_dev->private = par_dev_cb->private;
884 par_dev->flags = par_dev_cb->flags;
885 par_dev->irq_func = par_dev_cb->irq_func;
886 par_dev->waiting = 0;
887 par_dev->timeout = 5 * HZ;
888
889 par_dev->dev.parent = &port->bus_dev;
890 par_dev->dev.bus = &parport_bus_type;
891 ret = dev_set_name(&par_dev->dev, "%s.%d", devname, id);
892 if (ret)
893 goto err_free_devname;
894 par_dev->dev.release = free_pardevice;
895 par_dev->devmodel = true;
896 ret = device_register(&par_dev->dev);
897 if (ret) {
898 put_device(&par_dev->dev);
899 goto err_put_port;
900 }
901
902 /* Chain this onto the list */
903 par_dev->prev = NULL;
904 /*
905 * This function must not run from an irq handler so we don' t need
906 * to clear irq on the local CPU. -arca
907 */
908 spin_lock(&port->physport->pardevice_lock);
909
910 if (par_dev_cb->flags & PARPORT_DEV_EXCL) {
911 if (port->physport->devices) {
912 spin_unlock(&port->physport->pardevice_lock);
913 pr_debug("%s: cannot grant exclusive access for device %s\n",
914 port->name, name);
915 device_unregister(&par_dev->dev);
916 goto err_put_port;
917 }
918 port->flags |= PARPORT_FLAG_EXCL;
919 }
920
921 par_dev->next = port->physport->devices;
922 wmb(); /*
923 * Make sure that tmp->next is written before it's
924 * added to the list; see comments marked 'no locking
925 * required'
926 */
927 if (port->physport->devices)
928 port->physport->devices->prev = par_dev;
929 port->physport->devices = par_dev;
930 spin_unlock(&port->physport->pardevice_lock);
931
932 init_waitqueue_head(&par_dev->wait_q);
933 par_dev->timeslice = parport_default_timeslice;
934 par_dev->waitnext = NULL;
935 par_dev->waitprev = NULL;
936
937 /*
938 * This has to be run as last thing since init_state may need other
939 * pardevice fields. -arca
940 */
941 port->ops->init_state(par_dev, par_dev->state);
942 port->proc_device = par_dev;
943 parport_device_proc_register(par_dev);
944
945 return par_dev;
946
947err_free_devname:
948 kfree(devname);
949err_free_par_dev:
950 kfree(par_dev->state);
951err_put_par_dev:
952 if (!par_dev->devmodel)
953 kfree(par_dev);
954err_put_port:
955 parport_put_port(port);
956 module_put(port->ops->owner);
957
958 return NULL;
959}
960EXPORT_SYMBOL(parport_register_dev_model);
961
962/**
963 * parport_unregister_device - deregister a device on a parallel port
964 * @dev: pointer to structure representing device
965 *
966 * This undoes the effect of parport_register_device().
967 **/
968
969void parport_unregister_device(struct pardevice *dev)
970{
971 struct parport *port;
972
973#ifdef PARPORT_PARANOID
974 if (!dev) {
975 printk(KERN_ERR "parport_unregister_device: passed NULL\n");
976 return;
977 }
978#endif
979
980 port = dev->port->physport;
981
982 if (port->proc_device == dev) {
983 port->proc_device = NULL;
984 clear_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags);
985 parport_device_proc_unregister(dev);
986 }
987
988 if (port->cad == dev) {
989 printk(KERN_DEBUG "%s: %s forgot to release port\n",
990 port->name, dev->name);
991 parport_release(dev);
992 }
993
994 spin_lock(&port->pardevice_lock);
995 if (dev->next)
996 dev->next->prev = dev->prev;
997 if (dev->prev)
998 dev->prev->next = dev->next;
999 else
1000 port->devices = dev->next;
1001
1002 if (dev->flags & PARPORT_DEV_EXCL)
1003 port->flags &= ~PARPORT_FLAG_EXCL;
1004
1005 spin_unlock(&port->pardevice_lock);
1006
1007 /*
1008 * Make sure we haven't left any pointers around in the wait
1009 * list.
1010 */
1011 spin_lock_irq(&port->waitlist_lock);
1012 if (dev->waitprev || dev->waitnext || port->waithead == dev) {
1013 if (dev->waitprev)
1014 dev->waitprev->waitnext = dev->waitnext;
1015 else
1016 port->waithead = dev->waitnext;
1017 if (dev->waitnext)
1018 dev->waitnext->waitprev = dev->waitprev;
1019 else
1020 port->waittail = dev->waitprev;
1021 }
1022 spin_unlock_irq(&port->waitlist_lock);
1023
1024 kfree(dev->state);
1025 if (dev->devmodel)
1026 device_unregister(&dev->dev);
1027 else
1028 kfree(dev);
1029
1030 module_put(port->ops->owner);
1031 parport_put_port(port);
1032}
1033EXPORT_SYMBOL(parport_unregister_device);
1034
1035/**
1036 * parport_find_number - find a parallel port by number
1037 * @number: parallel port number
1038 *
1039 * This returns the parallel port with the specified number, or
1040 * %NULL if there is none.
1041 *
1042 * There is an implicit parport_get_port() done already; to throw
1043 * away the reference to the port that parport_find_number()
1044 * gives you, use parport_put_port().
1045 */
1046
1047struct parport *parport_find_number(int number)
1048{
1049 struct parport *port, *result = NULL;
1050
1051 if (list_empty(&portlist))
1052 get_lowlevel_driver();
1053
1054 spin_lock(&parportlist_lock);
1055 list_for_each_entry(port, &portlist, list) {
1056 if (port->number == number) {
1057 result = parport_get_port(port);
1058 break;
1059 }
1060 }
1061 spin_unlock(&parportlist_lock);
1062 return result;
1063}
1064EXPORT_SYMBOL(parport_find_number);
1065
1066/**
1067 * parport_find_base - find a parallel port by base address
1068 * @base: base I/O address
1069 *
1070 * This returns the parallel port with the specified base
1071 * address, or %NULL if there is none.
1072 *
1073 * There is an implicit parport_get_port() done already; to throw
1074 * away the reference to the port that parport_find_base()
1075 * gives you, use parport_put_port().
1076 */
1077
1078struct parport *parport_find_base(unsigned long base)
1079{
1080 struct parport *port, *result = NULL;
1081
1082 if (list_empty(&portlist))
1083 get_lowlevel_driver();
1084
1085 spin_lock(&parportlist_lock);
1086 list_for_each_entry(port, &portlist, list) {
1087 if (port->base == base) {
1088 result = parport_get_port(port);
1089 break;
1090 }
1091 }
1092 spin_unlock(&parportlist_lock);
1093 return result;
1094}
1095EXPORT_SYMBOL(parport_find_base);
1096
1097/**
1098 * parport_claim - claim access to a parallel port device
1099 * @dev: pointer to structure representing a device on the port
1100 *
1101 * This function will not block and so can be used from interrupt
1102 * context. If parport_claim() succeeds in claiming access to
1103 * the port it returns zero and the port is available to use. It
1104 * may fail (returning non-zero) if the port is in use by another
1105 * driver and that driver is not willing to relinquish control of
1106 * the port.
1107 **/
1108
1109int parport_claim(struct pardevice *dev)
1110{
1111 struct pardevice *oldcad;
1112 struct parport *port = dev->port->physport;
1113 unsigned long flags;
1114
1115 if (port->cad == dev) {
1116 printk(KERN_INFO "%s: %s already owner\n",
1117 dev->port->name,dev->name);
1118 return 0;
1119 }
1120
1121 /* Preempt any current device */
1122 write_lock_irqsave(&port->cad_lock, flags);
1123 oldcad = port->cad;
1124 if (oldcad) {
1125 if (oldcad->preempt) {
1126 if (oldcad->preempt(oldcad->private))
1127 goto blocked;
1128 port->ops->save_state(port, dev->state);
1129 } else
1130 goto blocked;
1131
1132 if (port->cad != oldcad) {
1133 /*
1134 * I think we'll actually deadlock rather than
1135 * get here, but just in case..
1136 */
1137 printk(KERN_WARNING
1138 "%s: %s released port when preempted!\n",
1139 port->name, oldcad->name);
1140 if (port->cad)
1141 goto blocked;
1142 }
1143 }
1144
1145 /* Can't fail from now on, so mark ourselves as no longer waiting. */
1146 if (dev->waiting & 1) {
1147 dev->waiting = 0;
1148
1149 /* Take ourselves out of the wait list again. */
1150 spin_lock_irq(&port->waitlist_lock);
1151 if (dev->waitprev)
1152 dev->waitprev->waitnext = dev->waitnext;
1153 else
1154 port->waithead = dev->waitnext;
1155 if (dev->waitnext)
1156 dev->waitnext->waitprev = dev->waitprev;
1157 else
1158 port->waittail = dev->waitprev;
1159 spin_unlock_irq(&port->waitlist_lock);
1160 dev->waitprev = dev->waitnext = NULL;
1161 }
1162
1163 /* Now we do the change of devices */
1164 port->cad = dev;
1165
1166#ifdef CONFIG_PARPORT_1284
1167 /* If it's a mux port, select it. */
1168 if (dev->port->muxport >= 0) {
1169 /* FIXME */
1170 port->muxsel = dev->port->muxport;
1171 }
1172
1173 /* If it's a daisy chain device, select it. */
1174 if (dev->daisy >= 0) {
1175 /* This could be lazier. */
1176 if (!parport_daisy_select(port, dev->daisy,
1177 IEEE1284_MODE_COMPAT))
1178 port->daisy = dev->daisy;
1179 }
1180#endif /* IEEE1284.3 support */
1181
1182 /* Restore control registers */
1183 port->ops->restore_state(port, dev->state);
1184 write_unlock_irqrestore(&port->cad_lock, flags);
1185 dev->time = jiffies;
1186 return 0;
1187
1188blocked:
1189 /*
1190 * If this is the first time we tried to claim the port, register an
1191 * interest. This is only allowed for devices sleeping in
1192 * parport_claim_or_block(), or those with a wakeup function.
1193 */
1194
1195 /* The cad_lock is still held for writing here */
1196 if (dev->waiting & 2 || dev->wakeup) {
1197 spin_lock(&port->waitlist_lock);
1198 if (test_and_set_bit(0, &dev->waiting) == 0) {
1199 /* First add ourselves to the end of the wait list. */
1200 dev->waitnext = NULL;
1201 dev->waitprev = port->waittail;
1202 if (port->waittail) {
1203 port->waittail->waitnext = dev;
1204 port->waittail = dev;
1205 } else
1206 port->waithead = port->waittail = dev;
1207 }
1208 spin_unlock(&port->waitlist_lock);
1209 }
1210 write_unlock_irqrestore(&port->cad_lock, flags);
1211 return -EAGAIN;
1212}
1213EXPORT_SYMBOL(parport_claim);
1214
1215/**
1216 * parport_claim_or_block - claim access to a parallel port device
1217 * @dev: pointer to structure representing a device on the port
1218 *
1219 * This behaves like parport_claim(), but will block if necessary
1220 * to wait for the port to be free. A return value of 1
1221 * indicates that it slept; 0 means that it succeeded without
1222 * needing to sleep. A negative error code indicates failure.
1223 **/
1224
1225int parport_claim_or_block(struct pardevice *dev)
1226{
1227 int r;
1228
1229 /*
1230 * Signal to parport_claim() that we can wait even without a
1231 * wakeup function.
1232 */
1233 dev->waiting = 2;
1234
1235 /* Try to claim the port. If this fails, we need to sleep. */
1236 r = parport_claim(dev);
1237 if (r == -EAGAIN) {
1238#ifdef PARPORT_DEBUG_SHARING
1239 printk(KERN_DEBUG "%s: parport_claim() returned -EAGAIN\n", dev->name);
1240#endif
1241 /*
1242 * FIXME!!! Use the proper locking for dev->waiting,
1243 * and make this use the "wait_event_interruptible()"
1244 * interfaces. The cli/sti that used to be here
1245 * did nothing.
1246 *
1247 * See also parport_release()
1248 */
1249
1250 /*
1251 * If dev->waiting is clear now, an interrupt
1252 * gave us the port and we would deadlock if we slept.
1253 */
1254 if (dev->waiting) {
1255 wait_event_interruptible(dev->wait_q,
1256 !dev->waiting);
1257 if (signal_pending(current))
1258 return -EINTR;
1259 r = 1;
1260 } else {
1261 r = 0;
1262#ifdef PARPORT_DEBUG_SHARING
1263 printk(KERN_DEBUG "%s: didn't sleep in parport_claim_or_block()\n",
1264 dev->name);
1265#endif
1266 }
1267
1268#ifdef PARPORT_DEBUG_SHARING
1269 if (dev->port->physport->cad != dev)
1270 printk(KERN_DEBUG "%s: exiting parport_claim_or_block but %s owns port!\n",
1271 dev->name, dev->port->physport->cad ?
1272 dev->port->physport->cad->name:"nobody");
1273#endif
1274 }
1275 dev->waiting = 0;
1276 return r;
1277}
1278EXPORT_SYMBOL(parport_claim_or_block);
1279
1280/**
1281 * parport_release - give up access to a parallel port device
1282 * @dev: pointer to structure representing parallel port device
1283 *
1284 * This function cannot fail, but it should not be called without
1285 * the port claimed. Similarly, if the port is already claimed
1286 * you should not try claiming it again.
1287 **/
1288
1289void parport_release(struct pardevice *dev)
1290{
1291 struct parport *port = dev->port->physport;
1292 struct pardevice *pd;
1293 unsigned long flags;
1294
1295 /* Make sure that dev is the current device */
1296 write_lock_irqsave(&port->cad_lock, flags);
1297 if (port->cad != dev) {
1298 write_unlock_irqrestore(&port->cad_lock, flags);
1299 printk(KERN_WARNING "%s: %s tried to release parport when not owner\n",
1300 port->name, dev->name);
1301 return;
1302 }
1303
1304#ifdef CONFIG_PARPORT_1284
1305 /* If this is on a mux port, deselect it. */
1306 if (dev->port->muxport >= 0) {
1307 /* FIXME */
1308 port->muxsel = -1;
1309 }
1310
1311 /* If this is a daisy device, deselect it. */
1312 if (dev->daisy >= 0) {
1313 parport_daisy_deselect_all(port);
1314 port->daisy = -1;
1315 }
1316#endif
1317
1318 port->cad = NULL;
1319 write_unlock_irqrestore(&port->cad_lock, flags);
1320
1321 /* Save control registers */
1322 port->ops->save_state(port, dev->state);
1323
1324 /*
1325 * If anybody is waiting, find out who's been there longest and
1326 * then wake them up. (Note: no locking required)
1327 */
1328 /* !!! LOCKING IS NEEDED HERE */
1329 for (pd = port->waithead; pd; pd = pd->waitnext) {
1330 if (pd->waiting & 2) { /* sleeping in claim_or_block */
1331 parport_claim(pd);
1332 if (waitqueue_active(&pd->wait_q))
1333 wake_up_interruptible(&pd->wait_q);
1334 return;
1335 } else if (pd->wakeup) {
1336 pd->wakeup(pd->private);
1337 if (dev->port->cad) /* racy but no matter */
1338 return;
1339 } else {
1340 printk(KERN_ERR "%s: don't know how to wake %s\n", port->name, pd->name);
1341 }
1342 }
1343
1344 /*
1345 * Nobody was waiting, so walk the list to see if anyone is
1346 * interested in being woken up. (Note: no locking required)
1347 */
1348 /* !!! LOCKING IS NEEDED HERE */
1349 for (pd = port->devices; !port->cad && pd; pd = pd->next) {
1350 if (pd->wakeup && pd != dev)
1351 pd->wakeup(pd->private);
1352 }
1353}
1354EXPORT_SYMBOL(parport_release);
1355
1356irqreturn_t parport_irq_handler(int irq, void *dev_id)
1357{
1358 struct parport *port = dev_id;
1359
1360 parport_generic_irq(port);
1361
1362 return IRQ_HANDLED;
1363}
1364EXPORT_SYMBOL(parport_irq_handler);
1365
1366MODULE_LICENSE("GPL");