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
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(bus: &parport_bus_type);
141}
142
143void parport_bus_exit(void)
144{
145 bus_unregister(bus: &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(bus: &parport_bus_type, NULL, data: port, fn: 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(bus: &parport_bus_type, NULL, data: port, fn: 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 * Iterates through all the devices connected to the bus and return 1
235 * if the device is a parallel port.
236 */
237
238static 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
278int __parport_register_driver(struct parport_driver *drv, struct module *owner,
279 const char *mod_name)
280{
281 /* using device model */
282 int ret;
283
284 /* initialize common driver fields */
285 drv->driver.name = drv->name;
286 drv->driver.bus = &parport_bus_type;
287 drv->driver.owner = owner;
288 drv->driver.mod_name = mod_name;
289 ret = driver_register(drv: &drv->driver);
290 if (ret)
291 return ret;
292
293 /*
294 * check if bus has any parallel port registered, if
295 * none is found then load the lowlevel driver.
296 */
297 ret = bus_for_each_dev(bus: &parport_bus_type, NULL, NULL,
298 fn: port_detect);
299 if (!ret)
300 get_lowlevel_driver();
301
302 mutex_lock(&registration_lock);
303 if (drv->match_port)
304 bus_for_each_dev(bus: &parport_bus_type, NULL, data: drv,
305 fn: port_check);
306 mutex_unlock(lock: &registration_lock);
307
308 return 0;
309}
310EXPORT_SYMBOL(__parport_register_driver);
311
312static int port_detach(struct device *dev, void *_drv)
313{
314 struct parport_driver *drv = _drv;
315
316 if (is_parport(dev) && drv->detach)
317 drv->detach(to_parport_dev(dev));
318
319 return 0;
320}
321
322/**
323 * parport_unregister_driver - deregister a parallel port device driver
324 * @drv: structure describing the driver that was given to
325 * parport_register_driver()
326 *
327 * This should be called by a parallel port device driver that
328 * has registered itself using parport_register_driver() when it
329 * is about to be unloaded.
330 *
331 * When it returns, the driver's attach() routine will no longer
332 * be called, and for each port that attach() was called for, the
333 * detach() routine will have been called.
334 *
335 * All the driver's attach() and detach() calls are guaranteed to have
336 * finished by the time this function returns.
337 **/
338
339void parport_unregister_driver(struct parport_driver *drv)
340{
341 mutex_lock(&registration_lock);
342 bus_for_each_dev(bus: &parport_bus_type, NULL, data: drv, fn: port_detach);
343 driver_unregister(drv: &drv->driver);
344 mutex_unlock(lock: &registration_lock);
345}
346EXPORT_SYMBOL(parport_unregister_driver);
347
348static void free_port(struct device *dev)
349{
350 int d;
351 struct parport *port = to_parport_dev(dev);
352
353 spin_lock(lock: &full_list_lock);
354 list_del(entry: &port->full_list);
355 spin_unlock(lock: &full_list_lock);
356 for (d = 0; d < 5; d++) {
357 kfree(objp: port->probe_info[d].class_name);
358 kfree(objp: port->probe_info[d].mfr);
359 kfree(objp: port->probe_info[d].model);
360 kfree(objp: port->probe_info[d].cmdset);
361 kfree(objp: port->probe_info[d].description);
362 }
363
364 kfree(objp: 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(dev: &port->bus_dev);
378
379 return to_parport_dev(dev);
380}
381EXPORT_SYMBOL(parport_get_port);
382
383void parport_del_port(struct parport *port)
384{
385 device_unregister(dev: &port->bus_dev);
386}
387EXPORT_SYMBOL(parport_del_port);
388
389/**
390 * parport_put_port - decrement a port's reference count
391 * @port: the port
392 *
393 * This should be called once for each call to parport_get_port(),
394 * once the port is no longer needed. When the reference count reaches
395 * zero (port is no longer used), free_port is called.
396 **/
397
398void parport_put_port(struct parport *port)
399{
400 put_device(dev: &port->bus_dev);
401}
402EXPORT_SYMBOL(parport_put_port);
403
404/**
405 * parport_register_port - register a parallel port
406 * @base: base I/O address
407 * @irq: IRQ line
408 * @dma: DMA channel
409 * @ops: pointer to the port driver's port operations structure
410 *
411 * When a parallel port (lowlevel) driver finds a port that
412 * should be made available to parallel port device drivers, it
413 * should call parport_register_port(). The @base, @irq, and
414 * @dma parameters are for the convenience of port drivers, and
415 * for ports where they aren't meaningful needn't be set to
416 * anything special. They can be altered afterwards by adjusting
417 * the relevant members of the parport structure that is returned
418 * and represents the port. They should not be tampered with
419 * after calling parport_announce_port, however.
420 *
421 * If there are parallel port device drivers in the system that
422 * have registered themselves using parport_register_driver(),
423 * they are not told about the port at this time; that is done by
424 * parport_announce_port().
425 *
426 * The @ops structure is allocated by the caller, and must not be
427 * deallocated before calling parport_remove_port().
428 *
429 * If there is no memory to allocate a new parport structure,
430 * this function will return %NULL.
431 **/
432
433struct parport *parport_register_port(unsigned long base, int irq, int dma,
434 struct parport_operations *ops)
435{
436 struct list_head *l;
437 struct parport *tmp;
438 int num;
439 int device;
440 int ret;
441
442 tmp = kzalloc(size: sizeof(struct parport), GFP_KERNEL);
443 if (!tmp)
444 return NULL;
445
446 /* Init our structure */
447 tmp->base = base;
448 tmp->irq = irq;
449 tmp->dma = dma;
450 tmp->muxport = tmp->daisy = tmp->muxsel = -1;
451 INIT_LIST_HEAD(list: &tmp->list);
452 tmp->ops = ops;
453 tmp->physport = tmp;
454 rwlock_init(&tmp->cad_lock);
455 spin_lock_init(&tmp->waitlist_lock);
456 spin_lock_init(&tmp->pardevice_lock);
457 tmp->ieee1284.mode = IEEE1284_MODE_COMPAT;
458 tmp->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
459 sema_init(sem: &tmp->ieee1284.irq, val: 0);
460 tmp->spintime = parport_default_spintime;
461 atomic_set(v: &tmp->ref_count, i: 1);
462
463 /* Search for the lowest free parport number. */
464
465 spin_lock(lock: &full_list_lock);
466 num = 0;
467 list_for_each(l, &all_ports) {
468 struct parport *p = list_entry(l, struct parport, full_list);
469
470 if (p->number != num++)
471 break;
472 }
473 tmp->portnum = tmp->number = num;
474 list_add_tail(new: &tmp->full_list, head: l);
475 spin_unlock(lock: &full_list_lock);
476
477 /*
478 * Now that the portnum is known finish doing the Init.
479 */
480 dev_set_name(dev: &tmp->bus_dev, name: "parport%d", tmp->portnum);
481 tmp->bus_dev.bus = &parport_bus_type;
482 tmp->bus_dev.release = free_port;
483 tmp->bus_dev.type = &parport_device_type;
484
485 tmp->name = dev_name(dev: &tmp->bus_dev);
486
487 for (device = 0; device < 5; device++)
488 /* assume the worst */
489 tmp->probe_info[device].class = PARPORT_CLASS_LEGACY;
490
491 ret = device_register(dev: &tmp->bus_dev);
492 if (ret) {
493 put_device(dev: &tmp->bus_dev);
494 return NULL;
495 }
496
497 return tmp;
498}
499EXPORT_SYMBOL(parport_register_port);
500
501/**
502 * parport_announce_port - tell device drivers about a parallel port
503 * @port: parallel port to announce
504 *
505 * After a port driver has registered a parallel port with
506 * parport_register_port, and performed any necessary
507 * initialisation or adjustments, it should call
508 * parport_announce_port() in order to notify all device drivers
509 * that have called parport_register_driver(). Their attach()
510 * functions will be called, with @port as the parameter.
511 **/
512
513void parport_announce_port(struct parport *port)
514{
515 int i;
516
517#ifdef CONFIG_PARPORT_1284
518 /* Analyse the IEEE1284.3 topology of the port. */
519 parport_daisy_init(port);
520#endif
521
522 if (!port->dev)
523 pr_warn("%s: fix this legacy no-device port driver!\n",
524 port->name);
525
526 parport_proc_register(pp: port);
527 mutex_lock(&registration_lock);
528 spin_lock_irq(lock: &parportlist_lock);
529 list_add_tail(new: &port->list, head: &portlist);
530 for (i = 1; i < 3; i++) {
531 struct parport *slave = port->slaves[i-1];
532 if (slave)
533 list_add_tail(new: &slave->list, head: &portlist);
534 }
535 spin_unlock_irq(lock: &parportlist_lock);
536
537 /* Let drivers know that new port(s) has arrived. */
538 attach_driver_chain(port);
539 for (i = 1; i < 3; i++) {
540 struct parport *slave = port->slaves[i-1];
541 if (slave)
542 attach_driver_chain(port: slave);
543 }
544 mutex_unlock(lock: &registration_lock);
545}
546EXPORT_SYMBOL(parport_announce_port);
547
548/**
549 * parport_remove_port - deregister a parallel port
550 * @port: parallel port to deregister
551 *
552 * When a parallel port driver is forcibly unloaded, or a
553 * parallel port becomes inaccessible, the port driver must call
554 * this function in order to deal with device drivers that still
555 * want to use it.
556 *
557 * The parport structure associated with the port has its
558 * operations structure replaced with one containing 'null'
559 * operations that return errors or just don't do anything.
560 *
561 * Any drivers that have registered themselves using
562 * parport_register_driver() are notified that the port is no
563 * longer accessible by having their detach() routines called
564 * with @port as the parameter.
565 **/
566
567void parport_remove_port(struct parport *port)
568{
569 int i;
570
571 mutex_lock(&registration_lock);
572
573 /* Spread the word. */
574 detach_driver_chain(port);
575
576#ifdef CONFIG_PARPORT_1284
577 /* Forget the IEEE1284.3 topology of the port. */
578 parport_daisy_fini(port);
579 for (i = 1; i < 3; i++) {
580 struct parport *slave = port->slaves[i-1];
581 if (!slave)
582 continue;
583 detach_driver_chain(port: slave);
584 parport_daisy_fini(port: slave);
585 }
586#endif
587
588 port->ops = &dead_ops;
589 spin_lock(lock: &parportlist_lock);
590 list_del_init(entry: &port->list);
591 for (i = 1; i < 3; i++) {
592 struct parport *slave = port->slaves[i-1];
593 if (slave)
594 list_del_init(entry: &slave->list);
595 }
596 spin_unlock(lock: &parportlist_lock);
597
598 mutex_unlock(lock: &registration_lock);
599
600 parport_proc_unregister(pp: port);
601
602 for (i = 1; i < 3; i++) {
603 struct parport *slave = port->slaves[i-1];
604 if (slave)
605 parport_put_port(slave);
606 }
607}
608EXPORT_SYMBOL(parport_remove_port);
609
610static void free_pardevice(struct device *dev)
611{
612 struct pardevice *par_dev = to_pardevice(dev);
613
614 kfree(objp: par_dev->name);
615 kfree(objp: par_dev);
616}
617
618/**
619 * parport_register_dev_model - register a device on a parallel port
620 * @port: port to which the device is attached
621 * @name: a name to refer to the device
622 * @par_dev_cb: struct containing callbacks
623 * @id: device number to be given to the device
624 *
625 * This function, called by parallel port device drivers,
626 * declares that a device is connected to a port, and tells the
627 * system all it needs to know.
628 *
629 * The struct pardev_cb contains pointer to callbacks. preemption
630 * callback function, @preempt, is called when this device driver
631 * has claimed access to the port but another device driver wants
632 * to use it. It is given, @private, as its parameter, and should
633 * return zero if it is willing for the system to release the port
634 * to another driver on its behalf. If it wants to keep control of
635 * the port it should return non-zero, and no action will be taken.
636 * It is good manners for the driver to try to release the port at
637 * the earliest opportunity after its preemption callback rejects a
638 * preemption attempt. Note that if a preemption callback is happy
639 * for preemption to go ahead, there is no need to release the
640 * port; it is done automatically. This function may not block, as
641 * it may be called from interrupt context. If the device driver
642 * does not support preemption, @preempt can be %NULL.
643 *
644 * The wake-up ("kick") callback function, @wakeup, is called when
645 * the port is available to be claimed for exclusive access; that
646 * is, parport_claim() is guaranteed to succeed when called from
647 * inside the wake-up callback function. If the driver wants to
648 * claim the port it should do so; otherwise, it need not take
649 * any action. This function may not block, as it may be called
650 * from interrupt context. If the device driver does not want to
651 * be explicitly invited to claim the port in this way, @wakeup can
652 * be %NULL.
653 *
654 * The interrupt handler, @irq_func, is called when an interrupt
655 * arrives from the parallel port. Note that if a device driver
656 * wants to use interrupts it should use parport_enable_irq(),
657 * and can also check the irq member of the parport structure
658 * representing the port.
659 *
660 * The parallel port (lowlevel) driver is the one that has called
661 * request_irq() and whose interrupt handler is called first.
662 * This handler does whatever needs to be done to the hardware to
663 * acknowledge the interrupt (for PC-style ports there is nothing
664 * special to be done). It then tells the IEEE 1284 code about
665 * the interrupt, which may involve reacting to an IEEE 1284
666 * event depending on the current IEEE 1284 phase. After this,
667 * it calls @irq_func. Needless to say, @irq_func will be called
668 * from interrupt context, and may not block.
669 *
670 * The %PARPORT_DEV_EXCL flag is for preventing port sharing, and
671 * so should only be used when sharing the port with other device
672 * drivers is impossible and would lead to incorrect behaviour.
673 * Use it sparingly! Normally, @flags will be zero.
674 *
675 * This function returns a pointer to a structure that represents
676 * the device on the port, or %NULL if there is not enough memory
677 * to allocate space for that structure.
678 **/
679
680struct pardevice *
681parport_register_dev_model(struct parport *port, const char *name,
682 const struct pardev_cb *par_dev_cb, int id)
683{
684 struct pardevice *par_dev;
685 int ret;
686 char *devname;
687
688 if (port->physport->flags & PARPORT_FLAG_EXCL) {
689 /* An exclusive device is registered. */
690 pr_err("%s: no more devices allowed\n", port->name);
691 return NULL;
692 }
693
694 if (par_dev_cb->flags & PARPORT_DEV_LURK) {
695 if (!par_dev_cb->preempt || !par_dev_cb->wakeup) {
696 pr_info("%s: refused to register lurking device (%s) without callbacks\n",
697 port->name, name);
698 return NULL;
699 }
700 }
701
702 if (par_dev_cb->flags & PARPORT_DEV_EXCL) {
703 if (port->physport->devices) {
704 /*
705 * If a device is already registered and this new
706 * device wants exclusive access, then no need to
707 * continue as we can not grant exclusive access to
708 * this device.
709 */
710 pr_err("%s: cannot grant exclusive access for device %s\n",
711 port->name, name);
712 return NULL;
713 }
714 }
715
716 if (!try_module_get(module: port->ops->owner))
717 return NULL;
718
719 parport_get_port(port);
720
721 par_dev = kzalloc(size: sizeof(*par_dev), GFP_KERNEL);
722 if (!par_dev)
723 goto err_put_port;
724
725 par_dev->state = kzalloc(size: sizeof(*par_dev->state), GFP_KERNEL);
726 if (!par_dev->state)
727 goto err_put_par_dev;
728
729 devname = kstrdup(s: name, GFP_KERNEL);
730 if (!devname)
731 goto err_free_par_dev;
732
733 par_dev->name = devname;
734 par_dev->port = port;
735 par_dev->daisy = -1;
736 par_dev->preempt = par_dev_cb->preempt;
737 par_dev->wakeup = par_dev_cb->wakeup;
738 par_dev->private = par_dev_cb->private;
739 par_dev->flags = par_dev_cb->flags;
740 par_dev->irq_func = par_dev_cb->irq_func;
741 par_dev->waiting = 0;
742 par_dev->timeout = 5 * HZ;
743
744 par_dev->dev.parent = &port->bus_dev;
745 par_dev->dev.bus = &parport_bus_type;
746 ret = dev_set_name(dev: &par_dev->dev, name: "%s.%d", devname, id);
747 if (ret)
748 goto err_free_devname;
749 par_dev->dev.release = free_pardevice;
750 par_dev->devmodel = true;
751 ret = device_register(dev: &par_dev->dev);
752 if (ret) {
753 kfree(objp: par_dev->state);
754 put_device(dev: &par_dev->dev);
755 goto err_put_port;
756 }
757
758 /* Chain this onto the list */
759 par_dev->prev = NULL;
760 /*
761 * This function must not run from an irq handler so we don' t need
762 * to clear irq on the local CPU. -arca
763 */
764 spin_lock(lock: &port->physport->pardevice_lock);
765
766 if (par_dev_cb->flags & PARPORT_DEV_EXCL) {
767 if (port->physport->devices) {
768 spin_unlock(lock: &port->physport->pardevice_lock);
769 pr_debug("%s: cannot grant exclusive access for device %s\n",
770 port->name, name);
771 kfree(objp: par_dev->state);
772 device_unregister(dev: &par_dev->dev);
773 goto err_put_port;
774 }
775 port->flags |= PARPORT_FLAG_EXCL;
776 }
777
778 par_dev->next = port->physport->devices;
779 wmb(); /*
780 * Make sure that tmp->next is written before it's
781 * added to the list; see comments marked 'no locking
782 * required'
783 */
784 if (port->physport->devices)
785 port->physport->devices->prev = par_dev;
786 port->physport->devices = par_dev;
787 spin_unlock(lock: &port->physport->pardevice_lock);
788
789 init_waitqueue_head(&par_dev->wait_q);
790 par_dev->timeslice = parport_default_timeslice;
791 par_dev->waitnext = NULL;
792 par_dev->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(par_dev, par_dev->state);
799 if (!test_and_set_bit(PARPORT_DEVPROC_REGISTERED, addr: &port->devflags)) {
800 port->proc_device = par_dev;
801 parport_device_proc_register(device: par_dev);
802 }
803
804 return par_dev;
805
806err_free_devname:
807 kfree(objp: devname);
808err_free_par_dev:
809 kfree(objp: par_dev->state);
810err_put_par_dev:
811 if (!par_dev->devmodel)
812 kfree(objp: par_dev);
813err_put_port:
814 parport_put_port(port);
815 module_put(module: port->ops->owner);
816
817 return NULL;
818}
819EXPORT_SYMBOL(parport_register_dev_model);
820
821/**
822 * parport_unregister_device - deregister a device on a parallel port
823 * @dev: pointer to structure representing device
824 *
825 * This undoes the effect of parport_register_device().
826 **/
827
828void parport_unregister_device(struct pardevice *dev)
829{
830 struct parport *port;
831
832#ifdef PARPORT_PARANOID
833 if (!dev) {
834 pr_err("%s: passed NULL\n", __func__);
835 return;
836 }
837#endif
838
839 port = dev->port->physport;
840
841 if (port->proc_device == dev) {
842 port->proc_device = NULL;
843 clear_bit(PARPORT_DEVPROC_REGISTERED, addr: &port->devflags);
844 parport_device_proc_unregister(device: dev);
845 }
846
847 if (port->cad == dev) {
848 printk(KERN_DEBUG "%s: %s forgot to release port\n",
849 port->name, dev->name);
850 parport_release(dev);
851 }
852
853 spin_lock(lock: &port->pardevice_lock);
854 if (dev->next)
855 dev->next->prev = dev->prev;
856 if (dev->prev)
857 dev->prev->next = dev->next;
858 else
859 port->devices = dev->next;
860
861 if (dev->flags & PARPORT_DEV_EXCL)
862 port->flags &= ~PARPORT_FLAG_EXCL;
863
864 spin_unlock(lock: &port->pardevice_lock);
865
866 /*
867 * Make sure we haven't left any pointers around in the wait
868 * list.
869 */
870 spin_lock_irq(lock: &port->waitlist_lock);
871 if (dev->waitprev || dev->waitnext || port->waithead == dev) {
872 if (dev->waitprev)
873 dev->waitprev->waitnext = dev->waitnext;
874 else
875 port->waithead = dev->waitnext;
876 if (dev->waitnext)
877 dev->waitnext->waitprev = dev->waitprev;
878 else
879 port->waittail = dev->waitprev;
880 }
881 spin_unlock_irq(lock: &port->waitlist_lock);
882
883 kfree(objp: dev->state);
884 device_unregister(dev: &dev->dev);
885
886 module_put(module: port->ops->owner);
887 parport_put_port(port);
888}
889EXPORT_SYMBOL(parport_unregister_device);
890
891/**
892 * parport_find_number - find a parallel port by number
893 * @number: parallel port number
894 *
895 * This returns the parallel port with the specified number, or
896 * %NULL if there is none.
897 *
898 * There is an implicit parport_get_port() done already; to throw
899 * away the reference to the port that parport_find_number()
900 * gives you, use parport_put_port().
901 */
902
903struct parport *parport_find_number(int number)
904{
905 struct parport *port, *result = NULL;
906
907 if (list_empty(head: &portlist))
908 get_lowlevel_driver();
909
910 spin_lock(lock: &parportlist_lock);
911 list_for_each_entry(port, &portlist, list) {
912 if (port->number == number) {
913 result = parport_get_port(port);
914 break;
915 }
916 }
917 spin_unlock(lock: &parportlist_lock);
918 return result;
919}
920EXPORT_SYMBOL(parport_find_number);
921
922/**
923 * parport_find_base - find a parallel port by base address
924 * @base: base I/O address
925 *
926 * This returns the parallel port with the specified base
927 * address, or %NULL if there is none.
928 *
929 * There is an implicit parport_get_port() done already; to throw
930 * away the reference to the port that parport_find_base()
931 * gives you, use parport_put_port().
932 */
933
934struct parport *parport_find_base(unsigned long base)
935{
936 struct parport *port, *result = NULL;
937
938 if (list_empty(head: &portlist))
939 get_lowlevel_driver();
940
941 spin_lock(lock: &parportlist_lock);
942 list_for_each_entry(port, &portlist, list) {
943 if (port->base == base) {
944 result = parport_get_port(port);
945 break;
946 }
947 }
948 spin_unlock(lock: &parportlist_lock);
949 return result;
950}
951EXPORT_SYMBOL(parport_find_base);
952
953/**
954 * parport_claim - claim access to a parallel port device
955 * @dev: pointer to structure representing a device on the port
956 *
957 * This function will not block and so can be used from interrupt
958 * context. If parport_claim() succeeds in claiming access to
959 * the port it returns zero and the port is available to use. It
960 * may fail (returning non-zero) if the port is in use by another
961 * driver and that driver is not willing to relinquish control of
962 * the port.
963 **/
964
965int parport_claim(struct pardevice *dev)
966{
967 struct pardevice *oldcad;
968 struct parport *port = dev->port->physport;
969 unsigned long flags;
970
971 if (port->cad == dev) {
972 pr_info("%s: %s already owner\n", dev->port->name, dev->name);
973 return 0;
974 }
975
976 /* Preempt any current device */
977 write_lock_irqsave(&port->cad_lock, flags);
978 oldcad = port->cad;
979 if (oldcad) {
980 if (oldcad->preempt) {
981 if (oldcad->preempt(oldcad->private))
982 goto blocked;
983 port->ops->save_state(port, dev->state);
984 } else
985 goto blocked;
986
987 if (port->cad != oldcad) {
988 /*
989 * I think we'll actually deadlock rather than
990 * get here, but just in case..
991 */
992 pr_warn("%s: %s released port when preempted!\n",
993 port->name, oldcad->name);
994 if (port->cad)
995 goto blocked;
996 }
997 }
998
999 /* Can't fail from now on, so mark ourselves as no longer waiting. */
1000 if (dev->waiting & 1) {
1001 dev->waiting = 0;
1002
1003 /* Take ourselves out of the wait list again. */
1004 spin_lock_irq(lock: &port->waitlist_lock);
1005 if (dev->waitprev)
1006 dev->waitprev->waitnext = dev->waitnext;
1007 else
1008 port->waithead = dev->waitnext;
1009 if (dev->waitnext)
1010 dev->waitnext->waitprev = dev->waitprev;
1011 else
1012 port->waittail = dev->waitprev;
1013 spin_unlock_irq(lock: &port->waitlist_lock);
1014 dev->waitprev = dev->waitnext = NULL;
1015 }
1016
1017 /* Now we do the change of devices */
1018 port->cad = dev;
1019
1020#ifdef CONFIG_PARPORT_1284
1021 /* If it's a mux port, select it. */
1022 if (dev->port->muxport >= 0) {
1023 /* FIXME */
1024 port->muxsel = dev->port->muxport;
1025 }
1026
1027 /* If it's a daisy chain device, select it. */
1028 if (dev->daisy >= 0) {
1029 /* This could be lazier. */
1030 if (!parport_daisy_select(port, daisy: dev->daisy,
1031 IEEE1284_MODE_COMPAT))
1032 port->daisy = dev->daisy;
1033 }
1034#endif /* IEEE1284.3 support */
1035
1036 /* Restore control registers */
1037 port->ops->restore_state(port, dev->state);
1038 write_unlock_irqrestore(&port->cad_lock, flags);
1039 dev->time = jiffies;
1040 return 0;
1041
1042blocked:
1043 /*
1044 * If this is the first time we tried to claim the port, register an
1045 * interest. This is only allowed for devices sleeping in
1046 * parport_claim_or_block(), or those with a wakeup function.
1047 */
1048
1049 /* The cad_lock is still held for writing here */
1050 if (dev->waiting & 2 || dev->wakeup) {
1051 spin_lock(lock: &port->waitlist_lock);
1052 if (test_and_set_bit(nr: 0, addr: &dev->waiting) == 0) {
1053 /* First add ourselves to the end of the wait list. */
1054 dev->waitnext = NULL;
1055 dev->waitprev = port->waittail;
1056 if (port->waittail) {
1057 port->waittail->waitnext = dev;
1058 port->waittail = dev;
1059 } else
1060 port->waithead = port->waittail = dev;
1061 }
1062 spin_unlock(lock: &port->waitlist_lock);
1063 }
1064 write_unlock_irqrestore(&port->cad_lock, flags);
1065 return -EAGAIN;
1066}
1067EXPORT_SYMBOL(parport_claim);
1068
1069/**
1070 * parport_claim_or_block - claim access to a parallel port device
1071 * @dev: pointer to structure representing a device on the port
1072 *
1073 * This behaves like parport_claim(), but will block if necessary
1074 * to wait for the port to be free. A return value of 1
1075 * indicates that it slept; 0 means that it succeeded without
1076 * needing to sleep. A negative error code indicates failure.
1077 **/
1078
1079int parport_claim_or_block(struct pardevice *dev)
1080{
1081 int r;
1082
1083 /*
1084 * Signal to parport_claim() that we can wait even without a
1085 * wakeup function.
1086 */
1087 dev->waiting = 2;
1088
1089 /* Try to claim the port. If this fails, we need to sleep. */
1090 r = parport_claim(dev);
1091 if (r == -EAGAIN) {
1092#ifdef PARPORT_DEBUG_SHARING
1093 printk(KERN_DEBUG "%s: parport_claim() returned -EAGAIN\n",
1094 dev->name);
1095#endif
1096 /*
1097 * FIXME!!! Use the proper locking for dev->waiting,
1098 * and make this use the "wait_event_interruptible()"
1099 * interfaces. The cli/sti that used to be here
1100 * did nothing.
1101 *
1102 * See also parport_release()
1103 */
1104
1105 /*
1106 * If dev->waiting is clear now, an interrupt
1107 * gave us the port and we would deadlock if we slept.
1108 */
1109 if (dev->waiting) {
1110 wait_event_interruptible(dev->wait_q,
1111 !dev->waiting);
1112 if (signal_pending(current))
1113 return -EINTR;
1114 r = 1;
1115 } else {
1116 r = 0;
1117#ifdef PARPORT_DEBUG_SHARING
1118 printk(KERN_DEBUG "%s: didn't sleep in parport_claim_or_block()\n",
1119 dev->name);
1120#endif
1121 }
1122
1123#ifdef PARPORT_DEBUG_SHARING
1124 if (dev->port->physport->cad != dev)
1125 printk(KERN_DEBUG "%s: exiting parport_claim_or_block but %s owns port!\n",
1126 dev->name, dev->port->physport->cad ?
1127 dev->port->physport->cad->name : "nobody");
1128#endif
1129 }
1130 dev->waiting = 0;
1131 return r;
1132}
1133EXPORT_SYMBOL(parport_claim_or_block);
1134
1135/**
1136 * parport_release - give up access to a parallel port device
1137 * @dev: pointer to structure representing parallel port device
1138 *
1139 * This function cannot fail, but it should not be called without
1140 * the port claimed. Similarly, if the port is already claimed
1141 * you should not try claiming it again.
1142 **/
1143
1144void parport_release(struct pardevice *dev)
1145{
1146 struct parport *port = dev->port->physport;
1147 struct pardevice *pd;
1148 unsigned long flags;
1149
1150 /* Make sure that dev is the current device */
1151 write_lock_irqsave(&port->cad_lock, flags);
1152 if (port->cad != dev) {
1153 write_unlock_irqrestore(&port->cad_lock, flags);
1154 pr_warn("%s: %s tried to release parport when not owner\n",
1155 port->name, dev->name);
1156 return;
1157 }
1158
1159#ifdef CONFIG_PARPORT_1284
1160 /* If this is on a mux port, deselect it. */
1161 if (dev->port->muxport >= 0) {
1162 /* FIXME */
1163 port->muxsel = -1;
1164 }
1165
1166 /* If this is a daisy device, deselect it. */
1167 if (dev->daisy >= 0) {
1168 parport_daisy_deselect_all(port);
1169 port->daisy = -1;
1170 }
1171#endif
1172
1173 port->cad = NULL;
1174 write_unlock_irqrestore(&port->cad_lock, flags);
1175
1176 /* Save control registers */
1177 port->ops->save_state(port, dev->state);
1178
1179 /*
1180 * If anybody is waiting, find out who's been there longest and
1181 * then wake them up. (Note: no locking required)
1182 */
1183 /* !!! LOCKING IS NEEDED HERE */
1184 for (pd = port->waithead; pd; pd = pd->waitnext) {
1185 if (pd->waiting & 2) { /* sleeping in claim_or_block */
1186 parport_claim(pd);
1187 if (waitqueue_active(wq_head: &pd->wait_q))
1188 wake_up_interruptible(&pd->wait_q);
1189 return;
1190 } else if (pd->wakeup) {
1191 pd->wakeup(pd->private);
1192 if (dev->port->cad) /* racy but no matter */
1193 return;
1194 } else {
1195 pr_err("%s: don't know how to wake %s\n",
1196 port->name, pd->name);
1197 }
1198 }
1199
1200 /*
1201 * Nobody was waiting, so walk the list to see if anyone is
1202 * interested in being woken up. (Note: no locking required)
1203 */
1204 /* !!! LOCKING IS NEEDED HERE */
1205 for (pd = port->devices; !port->cad && pd; pd = pd->next) {
1206 if (pd->wakeup && pd != dev)
1207 pd->wakeup(pd->private);
1208 }
1209}
1210EXPORT_SYMBOL(parport_release);
1211
1212irqreturn_t parport_irq_handler(int irq, void *dev_id)
1213{
1214 struct parport *port = dev_id;
1215
1216 parport_generic_irq(port);
1217
1218 return IRQ_HANDLED;
1219}
1220EXPORT_SYMBOL(parport_irq_handler);
1221
1222MODULE_LICENSE("GPL");
1223

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