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/signal.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
42 unsigned long parport_default_timeslice = PARPORT_DEFAULT_TIMESLICE;
43 int parport_default_spintime = DEFAULT_SPIN_TIME;
44
45 static LIST_HEAD(portlist);
46 static DEFINE_SPINLOCK(parportlist_lock);
47
48 /* list of all allocated ports, sorted by ->number */
49 static LIST_HEAD(all_ports);
50 static DEFINE_SPINLOCK(full_list_lock);
51
52 static LIST_HEAD(drivers);
53
54 static DEFINE_MUTEX(registration_lock);
55
56 /* What you can do to a port that's gone away.. */
57 static void dead_write_lines(struct parport *p, unsigned char b){}
58 static unsigned char dead_read_lines(struct parport *p) { return 0; }
59 static unsigned char dead_frob_lines(struct parport *p, unsigned char b,
60 unsigned char c) { return 0; }
61 static void dead_onearg(struct parport *p){}
62 static void dead_initstate(struct pardevice *d, struct parport_state *s) { }
63 static void dead_state(struct parport *p, struct parport_state *s) { }
64 static size_t dead_write(struct parport *p, const void *b, size_t l, int f)
65 { return 0; }
66 static size_t dead_read(struct parport *p, void *b, size_t l, int f)
67 { return 0; }
68 static 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
104 static struct device_type parport_device_type = {
105 .name = "parport",
106 };
107
108 static int is_parport(struct device *dev)
109 {
110 return dev->type == &parport_device_type;
111 }
112
113 static 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
133 static struct bus_type parport_bus_type = {
134 .name = "parport",
135 .probe = parport_probe,
136 };
137
138 int parport_bus_init(void)
139 {
140 return bus_register(&parport_bus_type);
141 }
142
143 void 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 */
154 static 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. */
165 static 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
181 static 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. */
192 static 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. */
208 static 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 */
223 static 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 * Iterates through all the devices connected to the bus and return 1
235 * if the device is a parallel port.
236 */
237
238 static int port_detect(struct device *dev, void *dev_drv)
239 {
240 if (is_parport(dev))
241 return 1;
242 return 0;
243 }
244
245 /**
246 * parport_register_driver - register a parallel port device driver
247 * @drv: structure describing the driver
248 * @owner: owner module of drv
249 * @mod_name: module name string
250 *
251 * This can be called by a parallel port device driver in order
252 * to receive notifications about ports being found in the
253 * system, as well as ports no longer available.
254 *
255 * If devmodel is true then the new device model is used
256 * for registration.
257 *
258 * The @drv structure is allocated by the caller and must not be
259 * deallocated until after calling parport_unregister_driver().
260 *
261 * If using the non device model:
262 * The driver's attach() function may block. The port that
263 * attach() is given will be valid for the duration of the
264 * callback, but if the driver wants to take a copy of the
265 * pointer it must call parport_get_port() to do so. Calling
266 * parport_register_device() on that port will do this for you.
267 *
268 * The driver's detach() function may block. The port that
269 * detach() is given will be valid for the duration of the
270 * callback, but if the driver wants to take a copy of the
271 * pointer it must call parport_get_port() to do so.
272 *
273 *
274 * Returns 0 on success. The non device model will always succeeds.
275 * but the new device model can fail and will return the error code.
276 **/
277
278 int __parport_register_driver(struct parport_driver *drv, struct module *owner,
279 const char *mod_name)
280 {
281 if (list_empty(&portlist))
282 get_lowlevel_driver();
283
284 if (drv->devmodel) {
285 /* using device model */
286 int ret;
287
288 /* initialize common driver fields */
289 drv->driver.name = drv->name;
290 drv->driver.bus = &parport_bus_type;
291 drv->driver.owner = owner;
292 drv->driver.mod_name = mod_name;
293 ret = driver_register(&drv->driver);
294 if (ret)
295 return ret;
296
297 /*
298 * check if bus has any parallel port registered, if
299 * none is found then load the lowlevel driver.
300 */
301 ret = bus_for_each_dev(&parport_bus_type, NULL, NULL,
302 port_detect);
303 if (!ret)
304 get_lowlevel_driver();
305
306 mutex_lock(®istration_lock);
307 if (drv->match_port)
308 bus_for_each_dev(&parport_bus_type, NULL, drv,
309 port_check);
310 mutex_unlock(®istration_lock);
311 } else {
312 struct parport *port;
313
314 drv->devmodel = false;
315
316 mutex_lock(®istration_lock);
317 list_for_each_entry(port, &portlist, list)
318 drv->attach(port);
319 list_add(&drv->list, &drivers);
320 mutex_unlock(®istration_lock);
321 }
322
323 return 0;
324 }
325 EXPORT_SYMBOL(__parport_register_driver);
326
327 static int port_detach(struct device *dev, void *_drv)
328 {
329 struct parport_driver *drv = _drv;
330
331 if (is_parport(dev) && drv->detach)
332 drv->detach(to_parport_dev(dev));
333
334 return 0;
335 }
336
337 /**
338 * parport_unregister_driver - deregister a parallel port device driver
339 * @drv: structure describing the driver that was given to
340 * parport_register_driver()
341 *
342 * This should be called by a parallel port device driver that
343 * has registered itself using parport_register_driver() when it
344 * is about to be unloaded.
345 *
346 * When it returns, the driver's attach() routine will no longer
347 * be called, and for each port that attach() was called for, the
348 * detach() routine will have been called.
349 *
350 * All the driver's attach() and detach() calls are guaranteed to have
351 * finished by the time this function returns.
352 **/
353
354 void parport_unregister_driver(struct parport_driver *drv)
355 {
356 struct parport *port;
357
358 mutex_lock(®istration_lock);
359 if (drv->devmodel) {
360 bus_for_each_dev(&parport_bus_type, NULL, drv, port_detach);
361 driver_unregister(&drv->driver);
362 } else {
363 list_del_init(&drv->list);
364 list_for_each_entry(port, &portlist, list)
365 drv->detach(port);
366 }
367 mutex_unlock(®istration_lock);
368 }
369 EXPORT_SYMBOL(parport_unregister_driver);
370
371 static void free_port(struct device *dev)
372 {
373 int d;
374 struct parport *port = to_parport_dev(dev);
375
376 spin_lock(&full_list_lock);
377 list_del(&port->full_list);
378 spin_unlock(&full_list_lock);
379 for (d = 0; d < 5; d++) {
380 kfree(port->probe_info[d].class_name);
381 kfree(port->probe_info[d].mfr);
382 kfree(port->probe_info[d].model);
383 kfree(port->probe_info[d].cmdset);
384 kfree(port->probe_info[d].description);
385 }
386
387 kfree(port->name);
388 kfree(port);
389 }
390
391 /**
392 * parport_get_port - increment a port's reference count
393 * @port: the port
394 *
395 * This ensures that a struct parport pointer remains valid
396 * until the matching parport_put_port() call.
397 **/
398
399 struct parport *parport_get_port(struct parport *port)
400 {
401 struct device *dev = get_device(&port->bus_dev);
402
403 return to_parport_dev(dev);
404 }
405 EXPORT_SYMBOL(parport_get_port);
406
407 void parport_del_port(struct parport *port)
408 {
409 device_unregister(&port->bus_dev);
410 }
411 EXPORT_SYMBOL(parport_del_port);
412
413 /**
414 * parport_put_port - decrement a port's reference count
415 * @port: the port
416 *
417 * This should be called once for each call to parport_get_port(),
418 * once the port is no longer needed. When the reference count reaches
419 * zero (port is no longer used), free_port is called.
420 **/
421
422 void parport_put_port(struct parport *port)
423 {
424 put_device(&port->bus_dev);
425 }
426 EXPORT_SYMBOL(parport_put_port);
427
428 /**
429 * parport_register_port - register a parallel port
430 * @base: base I/O address
431 * @irq: IRQ line
432 * @dma: DMA channel
433 * @ops: pointer to the port driver's port operations structure
434 *
435 * When a parallel port (lowlevel) driver finds a port that
436 * should be made available to parallel port device drivers, it
437 * should call parport_register_port(). The @base, @irq, and
438 * @dma parameters are for the convenience of port drivers, and
439 * for ports where they aren't meaningful needn't be set to
440 * anything special. They can be altered afterwards by adjusting
441 * the relevant members of the parport structure that is returned
442 * and represents the port. They should not be tampered with
443 * after calling parport_announce_port, however.
444 *
445 * If there are parallel port device drivers in the system that
446 * have registered themselves using parport_register_driver(),
447 * they are not told about the port at this time; that is done by
448 * parport_announce_port().
449 *
450 * The @ops structure is allocated by the caller, and must not be
451 * deallocated before calling parport_remove_port().
452 *
453 * If there is no memory to allocate a new parport structure,
454 * this function will return %NULL.
455 **/
456
457 struct parport *parport_register_port(unsigned long base, int irq, int dma,
458 struct parport_operations *ops)
459 {
460 struct list_head *l;
461 struct parport *tmp;
462 int num;
463 int device;
464 char *name;
465 int ret;
466
467 tmp = kzalloc(sizeof(struct parport), GFP_KERNEL);
468 if (!tmp)
469 return NULL;
470
471 /* Init our structure */
472 tmp->base = base;
473 tmp->irq = irq;
474 tmp->dma = dma;
475 tmp->muxport = tmp->daisy = tmp->muxsel = -1;
476 tmp->modes = 0;
477 INIT_LIST_HEAD(&tmp->list);
478 tmp->devices = tmp->cad = NULL;
479 tmp->flags = 0;
480 tmp->ops = ops;
481 tmp->physport = tmp;
482 memset(tmp->probe_info, 0, 5 * sizeof(struct parport_device_info));
483 rwlock_init(&tmp->cad_lock);
484 spin_lock_init(&tmp->waitlist_lock);
485 spin_lock_init(&tmp->pardevice_lock);
486 tmp->ieee1284.mode = IEEE1284_MODE_COMPAT;
487 tmp->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
488 sema_init(&tmp->ieee1284.irq, 0);
489 tmp->spintime = parport_default_spintime;
490 atomic_set(&tmp->ref_count, 1);
491 INIT_LIST_HEAD(&tmp->full_list);
492
493 name = kmalloc(15, GFP_KERNEL);
494 if (!name) {
495 kfree(tmp);
496 return NULL;
497 }
498 /* Search for the lowest free parport number. */
499
500 spin_lock(&full_list_lock);
501 for (l = all_ports.next, num = 0; l != &all_ports; l = l->next, num++) {
502 struct parport *p = list_entry(l, struct parport, full_list);
503 if (p->number != num)
504 break;
505 }
506 tmp->portnum = tmp->number = num;
507 list_add_tail(&tmp->full_list, l);
508 spin_unlock(&full_list_lock);
509
510 /*
511 * Now that the portnum is known finish doing the Init.
512 */
513 sprintf(name, "parport%d", tmp->portnum = tmp->number);
514 tmp->name = name;
515 tmp->bus_dev.bus = &parport_bus_type;
516 tmp->bus_dev.release = free_port;
517 dev_set_name(&tmp->bus_dev, name);
518 tmp->bus_dev.type = &parport_device_type;
519
520 for (device = 0; device < 5; device++)
521 /* assume the worst */
522 tmp->probe_info[device].class = PARPORT_CLASS_LEGACY;
523
524 tmp->waithead = tmp->waittail = NULL;
525
526 ret = device_register(&tmp->bus_dev);
527 if (ret) {
528 put_device(&tmp->bus_dev);
529 return NULL;
530 }
531
532 return tmp;
533 }
534 EXPORT_SYMBOL(parport_register_port);
535
536 /**
537 * parport_announce_port - tell device drivers about a parallel port
538 * @port: parallel port to announce
539 *
540 * After a port driver has registered a parallel port with
541 * parport_register_port, and performed any necessary
542 * initialisation or adjustments, it should call
543 * parport_announce_port() in order to notify all device drivers
544 * that have called parport_register_driver(). Their attach()
545 * functions will be called, with @port as the parameter.
546 **/
547
548 void parport_announce_port(struct parport *port)
549 {
550 int i;
551
552 #ifdef CONFIG_PARPORT_1284
553 /* Analyse the IEEE1284.3 topology of the port. */
554 parport_daisy_init(port);
555 #endif
556
557 if (!port->dev)
558 printk(KERN_WARNING "%s: fix this legacy no-device port driver!\n",
559 port->name);
560
561 parport_proc_register(port);
562 mutex_lock(®istration_lock);
563 spin_lock_irq(&parportlist_lock);
564 list_add_tail(&port->list, &portlist);
565 for (i = 1; i < 3; i++) {
566 struct parport *slave = port->slaves[i-1];
567 if (slave)
568 list_add_tail(&slave->list, &portlist);
569 }
570 spin_unlock_irq(&parportlist_lock);
571
572 /* Let drivers know that new port(s) has arrived. */
573 attach_driver_chain(port);
574 for (i = 1; i < 3; i++) {
575 struct parport *slave = port->slaves[i-1];
576 if (slave)
577 attach_driver_chain(slave);
578 }
579 mutex_unlock(®istration_lock);
580 }
581 EXPORT_SYMBOL(parport_announce_port);
582
583 /**
584 * parport_remove_port - deregister a parallel port
585 * @port: parallel port to deregister
586 *
587 * When a parallel port driver is forcibly unloaded, or a
588 * parallel port becomes inaccessible, the port driver must call
589 * this function in order to deal with device drivers that still
590 * want to use it.
591 *
592 * The parport structure associated with the port has its
593 * operations structure replaced with one containing 'null'
594 * operations that return errors or just don't do anything.
595 *
596 * Any drivers that have registered themselves using
597 * parport_register_driver() are notified that the port is no
598 * longer accessible by having their detach() routines called
599 * with @port as the parameter.
600 **/
601
602 void parport_remove_port(struct parport *port)
603 {
604 int i;
605
606 mutex_lock(®istration_lock);
607
608 /* Spread the word. */
609 detach_driver_chain(port);
610
611 #ifdef CONFIG_PARPORT_1284
612 /* Forget the IEEE1284.3 topology of the port. */
613 parport_daisy_fini(port);
614 for (i = 1; i < 3; i++) {
615 struct parport *slave = port->slaves[i-1];
616 if (!slave)
617 continue;
618 detach_driver_chain(slave);
619 parport_daisy_fini(slave);
620 }
621 #endif
622
623 port->ops = &dead_ops;
624 spin_lock(&parportlist_lock);
625 list_del_init(&port->list);
626 for (i = 1; i < 3; i++) {
627 struct parport *slave = port->slaves[i-1];
628 if (slave)
629 list_del_init(&slave->list);
630 }
631 spin_unlock(&parportlist_lock);
632
633 mutex_unlock(®istration_lock);
634
635 parport_proc_unregister(port);
636
637 for (i = 1; i < 3; i++) {
638 struct parport *slave = port->slaves[i-1];
639 if (slave)
640 parport_put_port(slave);
641 }
642 }
643 EXPORT_SYMBOL(parport_remove_port);
644
645 /**
646 * parport_register_device - register a device on a parallel port
647 * @port: port to which the device is attached
648 * @name: a name to refer to the device
649 * @pf: preemption callback
650 * @kf: kick callback (wake-up)
651 * @irq_func: interrupt handler
652 * @flags: registration flags
653 * @handle: data for callback functions
654 *
655 * This function, called by parallel port device drivers,
656 * declares that a device is connected to a port, and tells the
657 * system all it needs to know.
658 *
659 * The @name is allocated by the caller and must not be
660 * deallocated until the caller calls @parport_unregister_device
661 * for that device.
662 *
663 * The preemption callback function, @pf, is called when this
664 * device driver has claimed access to the port but another
665 * device driver wants to use it. It is given @handle as its
666 * parameter, and should return zero if it is willing for the
667 * system to release the port to another driver on its behalf.
668 * If it wants to keep control of the port it should return
669 * non-zero, and no action will be taken. It is good manners for
670 * the driver to try to release the port at the earliest
671 * opportunity after its preemption callback rejects a preemption
672 * attempt. Note that if a preemption callback is happy for
673 * preemption to go ahead, there is no need to release the port;
674 * it is done automatically. This function may not block, as it
675 * may be called from interrupt context. If the device driver
676 * does not support preemption, @pf can be %NULL.
677 *
678 * The wake-up ("kick") callback function, @kf, is called when
679 * the port is available to be claimed for exclusive access; that
680 * is, parport_claim() is guaranteed to succeed when called from
681 * inside the wake-up callback function. If the driver wants to
682 * claim the port it should do so; otherwise, it need not take
683 * any action. This function may not block, as it may be called
684 * from interrupt context. If the device driver does not want to
685 * be explicitly invited to claim the port in this way, @kf can
686 * be %NULL.
687 *
688 * The interrupt handler, @irq_func, is called when an interrupt
689 * arrives from the parallel port. Note that if a device driver
690 * wants to use interrupts it should use parport_enable_irq(),
691 * and can also check the irq member of the parport structure
692 * representing the port.
693 *
694 * The parallel port (lowlevel) driver is the one that has called
695 * request_irq() and whose interrupt handler is called first.
696 * This handler does whatever needs to be done to the hardware to
697 * acknowledge the interrupt (for PC-style ports there is nothing
698 * special to be done). It then tells the IEEE 1284 code about
699 * the interrupt, which may involve reacting to an IEEE 1284
700 * event depending on the current IEEE 1284 phase. After this,
701 * it calls @irq_func. Needless to say, @irq_func will be called
702 * from interrupt context, and may not block.
703 *
704 * The %PARPORT_DEV_EXCL flag is for preventing port sharing, and
705 * so should only be used when sharing the port with other device
706 * drivers is impossible and would lead to incorrect behaviour.
707 * Use it sparingly! Normally, @flags will be zero.
708 *
709 * This function returns a pointer to a structure that represents
710 * the device on the port, or %NULL if there is not enough memory
711 * to allocate space for that structure.
712 **/
713
714 struct pardevice *
715 parport_register_device(struct parport *port, const char *name,
716 int (*pf)(void *), void (*kf)(void *),
717 void (*irq_func)(void *),
718 int flags, void *handle)
719 {
720 struct pardevice *tmp;
721
722 if (port->physport->flags & PARPORT_FLAG_EXCL) {
723 /* An exclusive device is registered. */
724 printk(KERN_DEBUG "%s: no more devices allowed\n",
725 port->name);
726 return NULL;
727 }
728
729 if (flags & PARPORT_DEV_LURK) {
730 if (!pf || !kf) {
731 printk(KERN_INFO "%s: refused to register lurking device (%s) without callbacks\n", port->name, name);
732 return NULL;
733 }
734 }
735
736 if (flags & PARPORT_DEV_EXCL) {
737 if (port->physport->devices) {
738 /*
739 * If a device is already registered and this new
740 * device wants exclusive access, then no need to
741 * continue as we can not grant exclusive access to
742 * this device.
743 */
744 pr_err("%s: cannot grant exclusive access for device %s\n",
745 port->name, name);
746 return NULL;
747 }
748 }
749
750 /*
751 * We up our own module reference count, and that of the port
752 * on which a device is to be registered, to ensure that
753 * neither of us gets unloaded while we sleep in (e.g.)
754 * kmalloc.
755 */
756 if (!try_module_get(port->ops->owner))
757 return NULL;
758
759 parport_get_port(port);
760
761 tmp = kmalloc(sizeof(struct pardevice), GFP_KERNEL);
762 if (!tmp)
763 goto out;
764
765 tmp->state = kmalloc(sizeof(struct parport_state), GFP_KERNEL);
766 if (!tmp->state)
767 goto out_free_pardevice;
768
769 tmp->name = name;
770 tmp->port = port;
771 tmp->daisy = -1;
772 tmp->preempt = pf;
773 tmp->wakeup = kf;
774 tmp->private = handle;
775 tmp->flags = flags;
776 tmp->irq_func = irq_func;
777 tmp->waiting = 0;
778 tmp->timeout = 5 * HZ;
779 tmp->devmodel = false;
780
781 /* Chain this onto the list */
782 tmp->prev = NULL;
783 /*
784 * This function must not run from an irq handler so we don' t need
785 * to clear irq on the local CPU. -arca
786 */
787 spin_lock(&port->physport->pardevice_lock);
788
789 if (flags & PARPORT_DEV_EXCL) {
790 if (port->physport->devices) {
791 spin_unlock(&port->physport->pardevice_lock);
792 printk(KERN_DEBUG
793 "%s: cannot grant exclusive access for device %s\n",
794 port->name, name);
795 goto out_free_all;
796 }
797 port->flags |= PARPORT_FLAG_EXCL;
798 }
799
800 tmp->next = port->physport->devices;
801 wmb(); /*
802 * Make sure that tmp->next is written before it's
803 * added to the list; see comments marked 'no locking
804 * required'
805 */
806 if (port->physport->devices)
807 port->physport->devices->prev = tmp;
808 port->physport->devices = tmp;
809 spin_unlock(&port->physport->pardevice_lock);
810
811 init_waitqueue_head(&tmp->wait_q);
812 tmp->timeslice = parport_default_timeslice;
813 tmp->waitnext = tmp->waitprev = NULL;
814
815 /*
816 * This has to be run as last thing since init_state may need other
817 * pardevice fields. -arca
818 */
819 port->ops->init_state(tmp, tmp->state);
820 if (!test_and_set_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags)) {
821 port->proc_device = tmp;
822 parport_device_proc_register(tmp);
823 }
824 return tmp;
825
826 out_free_all:
827 kfree(tmp->state);
828 out_free_pardevice:
829 kfree(tmp);
830 out:
831 parport_put_port(port);
832 module_put(port->ops->owner);
833
834 return NULL;
835 }
836 EXPORT_SYMBOL(parport_register_device);
837
838 static void free_pardevice(struct device *dev)
839 {
840 struct pardevice *par_dev = to_pardevice(dev);
841
842 kfree(par_dev->name);
843 kfree(par_dev);
844 }
845
846 struct pardevice *
847 parport_register_dev_model(struct parport *port, const char *name,
848 const struct pardev_cb *par_dev_cb, int id)
849 {
850 struct pardevice *par_dev;
851 int ret;
852 char *devname;
853
854 if (port->physport->flags & PARPORT_FLAG_EXCL) {
855 /* An exclusive device is registered. */
856 pr_err("%s: no more devices allowed\n", port->name);
857 return NULL;
858 }
859
860 if (par_dev_cb->flags & PARPORT_DEV_LURK) {
861 if (!par_dev_cb->preempt || !par_dev_cb->wakeup) {
862 pr_info("%s: refused to register lurking device (%s) without callbacks\n",
863 port->name, name);
864 return NULL;
865 }
866 }
867
868 if (par_dev_cb->flags & PARPORT_DEV_EXCL) {
869 if (port->physport->devices) {
870 /*
871 * If a device is already registered and this new
872 * device wants exclusive access, then no need to
873 * continue as we can not grant exclusive access to
874 * this device.
875 */
876 pr_err("%s: cannot grant exclusive access for device %s\n",
877 port->name, name);
878 return NULL;
879 }
880 }
881
882 if (!try_module_get(port->ops->owner))
883 return NULL;
884
885 parport_get_port(port);
886
887 par_dev = kzalloc(sizeof(*par_dev), GFP_KERNEL);
888 if (!par_dev)
889 goto err_put_port;
890
891 par_dev->state = kzalloc(sizeof(*par_dev->state), GFP_KERNEL);
892 if (!par_dev->state)
893 goto err_put_par_dev;
894
895 devname = kstrdup(name, GFP_KERNEL);
896 if (!devname)
897 goto err_free_par_dev;
898
899 par_dev->name = devname;
900 par_dev->port = port;
901 par_dev->daisy = -1;
902 par_dev->preempt = par_dev_cb->preempt;
903 par_dev->wakeup = par_dev_cb->wakeup;
904 par_dev->private = par_dev_cb->private;
905 par_dev->flags = par_dev_cb->flags;
906 par_dev->irq_func = par_dev_cb->irq_func;
907 par_dev->waiting = 0;
908 par_dev->timeout = 5 * HZ;
909
910 par_dev->dev.parent = &port->bus_dev;
911 par_dev->dev.bus = &parport_bus_type;
912 ret = dev_set_name(&par_dev->dev, "%s.%d", devname, id);
913 if (ret)
914 goto err_free_devname;
915 par_dev->dev.release = free_pardevice;
916 par_dev->devmodel = true;
917 ret = device_register(&par_dev->dev);
918 if (ret) {
919 kfree(par_dev->state);
920 put_device(&par_dev->dev);
921 goto err_put_port;
922 }
923
924 /* Chain this onto the list */
925 par_dev->prev = NULL;
926 /*
927 * This function must not run from an irq handler so we don' t need
928 * to clear irq on the local CPU. -arca
929 */
930 spin_lock(&port->physport->pardevice_lock);
931
932 if (par_dev_cb->flags & PARPORT_DEV_EXCL) {
933 if (port->physport->devices) {
934 spin_unlock(&port->physport->pardevice_lock);
935 pr_debug("%s: cannot grant exclusive access for device %s\n",
936 port->name, name);
937 kfree(par_dev->state);
938 device_unregister(&par_dev->dev);
939 goto err_put_port;
940 }
941 port->flags |= PARPORT_FLAG_EXCL;
942 }
943
944 par_dev->next = port->physport->devices;
945 wmb(); /*
946 * Make sure that tmp->next is written before it's
947 * added to the list; see comments marked 'no locking
948 * required'
949 */
950 if (port->physport->devices)
951 port->physport->devices->prev = par_dev;
952 port->physport->devices = par_dev;
953 spin_unlock(&port->physport->pardevice_lock);
954
955 init_waitqueue_head(&par_dev->wait_q);
956 par_dev->timeslice = parport_default_timeslice;
957 par_dev->waitnext = NULL;
958 par_dev->waitprev = NULL;
959
960 /*
961 * This has to be run as last thing since init_state may need other
962 * pardevice fields. -arca
963 */
964 port->ops->init_state(par_dev, par_dev->state);
965 if (!test_and_set_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags)) {
966 port->proc_device = par_dev;
967 parport_device_proc_register(par_dev);
968 }
969
970 return par_dev;
971
972 err_free_devname:
973 kfree(devname);
974 err_free_par_dev:
975 kfree(par_dev->state);
976 err_put_par_dev:
977 if (!par_dev->devmodel)
978 kfree(par_dev);
979 err_put_port:
980 parport_put_port(port);
981 module_put(port->ops->owner);
982
983 return NULL;
984 }
985 EXPORT_SYMBOL(parport_register_dev_model);
986
987 /**
988 * parport_unregister_device - deregister a device on a parallel port
989 * @dev: pointer to structure representing device
990 *
991 * This undoes the effect of parport_register_device().
992 **/
993
994 void parport_unregister_device(struct pardevice *dev)
995 {
996 struct parport *port;
997
998 #ifdef PARPORT_PARANOID
999 if (!dev) {
1000 printk(KERN_ERR "parport_unregister_device: passed NULL\n");
1001 return;
1002 }
1003 #endif
1004
1005 port = dev->port->physport;
1006
1007 if (port->proc_device == dev) {
1008 port->proc_device = NULL;
1009 clear_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags);
1010 parport_device_proc_unregister(dev);
1011 }
1012
1013 if (port->cad == dev) {
1014 printk(KERN_DEBUG "%s: %s forgot to release port\n",
1015 port->name, dev->name);
1016 parport_release(dev);
1017 }
1018
1019 spin_lock(&port->pardevice_lock);
1020 if (dev->next)
1021 dev->next->prev = dev->prev;
1022 if (dev->prev)
1023 dev->prev->next = dev->next;
1024 else
1025 port->devices = dev->next;
1026
1027 if (dev->flags & PARPORT_DEV_EXCL)
1028 port->flags &= ~PARPORT_FLAG_EXCL;
1029
1030 spin_unlock(&port->pardevice_lock);
1031
1032 /*
1033 * Make sure we haven't left any pointers around in the wait
1034 * list.
1035 */
1036 spin_lock_irq(&port->waitlist_lock);
1037 if (dev->waitprev || dev->waitnext || port->waithead == dev) {
1038 if (dev->waitprev)
1039 dev->waitprev->waitnext = dev->waitnext;
1040 else
1041 port->waithead = dev->waitnext;
1042 if (dev->waitnext)
1043 dev->waitnext->waitprev = dev->waitprev;
1044 else
1045 port->waittail = dev->waitprev;
1046 }
1047 spin_unlock_irq(&port->waitlist_lock);
1048
1049 kfree(dev->state);
1050 if (dev->devmodel)
1051 device_unregister(&dev->dev);
1052 else
1053 kfree(dev);
1054
1055 module_put(port->ops->owner);
1056 parport_put_port(port);
1057 }
1058 EXPORT_SYMBOL(parport_unregister_device);
1059
1060 /**
1061 * parport_find_number - find a parallel port by number
1062 * @number: parallel port number
1063 *
1064 * This returns the parallel port with the specified number, or
1065 * %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_number()
1069 * gives you, use parport_put_port().
1070 */
1071
1072 struct parport *parport_find_number(int number)
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->number == number) {
1082 result = parport_get_port(port);
1083 break;
1084 }
1085 }
1086 spin_unlock(&parportlist_lock);
1087 return result;
1088 }
1089 EXPORT_SYMBOL(parport_find_number);
1090
1091 /**
1092 * parport_find_base - find a parallel port by base address
1093 * @base: base I/O address
1094 *
1095 * This returns the parallel port with the specified base
1096 * address, or %NULL if there is none.
1097 *
1098 * There is an implicit parport_get_port() done already; to throw
1099 * away the reference to the port that parport_find_base()
1100 * gives you, use parport_put_port().
1101 */
1102
1103 struct parport *parport_find_base(unsigned long base)
1104 {
1105 struct parport *port, *result = NULL;
1106
1107 if (list_empty(&portlist))
1108 get_lowlevel_driver();
1109
1110 spin_lock(&parportlist_lock);
1111 list_for_each_entry(port, &portlist, list) {
1112 if (port->base == base) {
1113 result = parport_get_port(port);
1114 break;
1115 }
1116 }
1117 spin_unlock(&parportlist_lock);
1118 return result;
1119 }
1120 EXPORT_SYMBOL(parport_find_base);
1121
1122 /**
1123 * parport_claim - claim access to a parallel port device
1124 * @dev: pointer to structure representing a device on the port
1125 *
1126 * This function will not block and so can be used from interrupt
1127 * context. If parport_claim() succeeds in claiming access to
1128 * the port it returns zero and the port is available to use. It
1129 * may fail (returning non-zero) if the port is in use by another
1130 * driver and that driver is not willing to relinquish control of
1131 * the port.
1132 **/
1133
1134 int parport_claim(struct pardevice *dev)
1135 {
1136 struct pardevice *oldcad;
1137 struct parport *port = dev->port->physport;
1138 unsigned long flags;
1139
1140 if (port->cad == dev) {
1141 printk(KERN_INFO "%s: %s already owner\n",
1142 dev->port->name,dev->name);
1143 return 0;
1144 }
1145
1146 /* Preempt any current device */
1147 write_lock_irqsave(&port->cad_lock, flags);
1148 oldcad = port->cad;
1149 if (oldcad) {
1150 if (oldcad->preempt) {
1151 if (oldcad->preempt(oldcad->private))
1152 goto blocked;
1153 port->ops->save_state(port, dev->state);
1154 } else
1155 goto blocked;
1156
1157 if (port->cad != oldcad) {
1158 /*
1159 * I think we'll actually deadlock rather than
1160 * get here, but just in case..
1161 */
1162 printk(KERN_WARNING
1163 "%s: %s released port when preempted!\n",
1164 port->name, oldcad->name);
1165 if (port->cad)
1166 goto blocked;
1167 }
1168 }
1169
1170 /* Can't fail from now on, so mark ourselves as no longer waiting. */
1171 if (dev->waiting & 1) {
1172 dev->waiting = 0;
1173
1174 /* Take ourselves out of the wait list again. */
1175 spin_lock_irq(&port->waitlist_lock);
1176 if (dev->waitprev)
1177 dev->waitprev->waitnext = dev->waitnext;
1178 else
1179 port->waithead = dev->waitnext;
1180 if (dev->waitnext)
1181 dev->waitnext->waitprev = dev->waitprev;
1182 else
1183 port->waittail = dev->waitprev;
1184 spin_unlock_irq(&port->waitlist_lock);
1185 dev->waitprev = dev->waitnext = NULL;
1186 }
1187
1188 /* Now we do the change of devices */
1189 port->cad = dev;
1190
1191 #ifdef CONFIG_PARPORT_1284
1192 /* If it's a mux port, select it. */
1193 if (dev->port->muxport >= 0) {
1194 /* FIXME */
1195 port->muxsel = dev->port->muxport;
1196 }
1197
1198 /* If it's a daisy chain device, select it. */
1199 if (dev->daisy >= 0) {
1200 /* This could be lazier. */
1201 if (!parport_daisy_select(port, dev->daisy,
1202 IEEE1284_MODE_COMPAT))
1203 port->daisy = dev->daisy;
1204 }
1205 #endif /* IEEE1284.3 support */
1206
1207 /* Restore control registers */
1208 port->ops->restore_state(port, dev->state);
1209 write_unlock_irqrestore(&port->cad_lock, flags);
1210 dev->time = jiffies;
1211 return 0;
1212
1213 blocked:
1214 /*
1215 * If this is the first time we tried to claim the port, register an
1216 * interest. This is only allowed for devices sleeping in
1217 * parport_claim_or_block(), or those with a wakeup function.
1218 */
1219
1220 /* The cad_lock is still held for writing here */
1221 if (dev->waiting & 2 || dev->wakeup) {
1222 spin_lock(&port->waitlist_lock);
1223 if (test_and_set_bit(0, &dev->waiting) == 0) {
1224 /* First add ourselves to the end of the wait list. */
1225 dev->waitnext = NULL;
1226 dev->waitprev = port->waittail;
1227 if (port->waittail) {
1228 port->waittail->waitnext = dev;
1229 port->waittail = dev;
1230 } else
1231 port->waithead = port->waittail = dev;
1232 }
1233 spin_unlock(&port->waitlist_lock);
1234 }
1235 write_unlock_irqrestore(&port->cad_lock, flags);
1236 return -EAGAIN;
1237 }
1238 EXPORT_SYMBOL(parport_claim);
1239
1240 /**
1241 * parport_claim_or_block - claim access to a parallel port device
1242 * @dev: pointer to structure representing a device on the port
1243 *
1244 * This behaves like parport_claim(), but will block if necessary
1245 * to wait for the port to be free. A return value of 1
1246 * indicates that it slept; 0 means that it succeeded without
1247 * needing to sleep. A negative error code indicates failure.
1248 **/
1249
1250 int parport_claim_or_block(struct pardevice *dev)
1251 {
1252 int r;
1253
1254 /*
1255 * Signal to parport_claim() that we can wait even without a
1256 * wakeup function.
1257 */
1258 dev->waiting = 2;
1259
1260 /* Try to claim the port. If this fails, we need to sleep. */
1261 r = parport_claim(dev);
1262 if (r == -EAGAIN) {
1263 #ifdef PARPORT_DEBUG_SHARING
1264 printk(KERN_DEBUG "%s: parport_claim() returned -EAGAIN\n", dev->name);
1265 #endif
1266 /*
1267 * FIXME!!! Use the proper locking for dev->waiting,
1268 * and make this use the "wait_event_interruptible()"
1269 * interfaces. The cli/sti that used to be here
1270 * did nothing.
1271 *
1272 * See also parport_release()
1273 */
1274
1275 /*
1276 * If dev->waiting is clear now, an interrupt
1277 * gave us the port and we would deadlock if we slept.
1278 */
1279 if (dev->waiting) {
1280 wait_event_interruptible(dev->wait_q,
1281 !dev->waiting);
1282 if (signal_pending(current))
1283 return -EINTR;
1284 r = 1;
1285 } else {
1286 r = 0;
1287 #ifdef PARPORT_DEBUG_SHARING
1288 printk(KERN_DEBUG "%s: didn't sleep in parport_claim_or_block()\n",
1289 dev->name);
1290 #endif
1291 }
1292
1293 #ifdef PARPORT_DEBUG_SHARING
1294 if (dev->port->physport->cad != dev)
1295 printk(KERN_DEBUG "%s: exiting parport_claim_or_block but %s owns port!\n",
1296 dev->name, dev->port->physport->cad ?
1297 dev->port->physport->cad->name:"nobody");
1298 #endif
1299 }
1300 dev->waiting = 0;
1301 return r;
1302 }
1303 EXPORT_SYMBOL(parport_claim_or_block);
1304
1305 /**
1306 * parport_release - give up access to a parallel port device
1307 * @dev: pointer to structure representing parallel port device
1308 *
1309 * This function cannot fail, but it should not be called without
1310 * the port claimed. Similarly, if the port is already claimed
1311 * you should not try claiming it again.
1312 **/
1313
1314 void parport_release(struct pardevice *dev)
1315 {
1316 struct parport *port = dev->port->physport;
1317 struct pardevice *pd;
1318 unsigned long flags;
1319
1320 /* Make sure that dev is the current device */
1321 write_lock_irqsave(&port->cad_lock, flags);
1322 if (port->cad != dev) {
1323 write_unlock_irqrestore(&port->cad_lock, flags);
1324 printk(KERN_WARNING "%s: %s tried to release parport when not owner\n",
1325 port->name, dev->name);
1326 return;
1327 }
1328
1329 #ifdef CONFIG_PARPORT_1284
1330 /* If this is on a mux port, deselect it. */
1331 if (dev->port->muxport >= 0) {
1332 /* FIXME */
1333 port->muxsel = -1;
1334 }
1335
1336 /* If this is a daisy device, deselect it. */
1337 if (dev->daisy >= 0) {
1338 parport_daisy_deselect_all(port);
1339 port->daisy = -1;
1340 }
1341 #endif
1342
1343 port->cad = NULL;
1344 write_unlock_irqrestore(&port->cad_lock, flags);
1345
1346 /* Save control registers */
1347 port->ops->save_state(port, dev->state);
1348
1349 /*
1350 * If anybody is waiting, find out who's been there longest and
1351 * then wake them up. (Note: no locking required)
1352 */
1353 /* !!! LOCKING IS NEEDED HERE */
1354 for (pd = port->waithead; pd; pd = pd->waitnext) {
1355 if (pd->waiting & 2) { /* sleeping in claim_or_block */
1356 parport_claim(pd);
1357 if (waitqueue_active(&pd->wait_q))
1358 wake_up_interruptible(&pd->wait_q);
1359 return;
1360 } else if (pd->wakeup) {
1361 pd->wakeup(pd->private);
1362 if (dev->port->cad) /* racy but no matter */
1363 return;
1364 } else {
1365 printk(KERN_ERR "%s: don't know how to wake %s\n", port->name, pd->name);
1366 }
1367 }
1368
1369 /*
1370 * Nobody was waiting, so walk the list to see if anyone is
1371 * interested in being woken up. (Note: no locking required)
1372 */
1373 /* !!! LOCKING IS NEEDED HERE */
1374 for (pd = port->devices; !port->cad && pd; pd = pd->next) {
1375 if (pd->wakeup && pd != dev)
1376 pd->wakeup(pd->private);
1377 }
1378 }
1379 EXPORT_SYMBOL(parport_release);
1380
1381 irqreturn_t parport_irq_handler(int irq, void *dev_id)
1382 {
1383 struct parport *port = dev_id;
1384
1385 parport_generic_irq(port);
1386
1387 return IRQ_HANDLED;
1388 }
1389 EXPORT_SYMBOL(parport_irq_handler);
1390
1391 MODULE_LICENSE("GPL");