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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/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"); |