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