Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* $Id: parport_share.c,v 1.15 1998/01/11 12:06:17 philip Exp $ |
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 | ||
1da177e4 LT |
20 | #include <linux/module.h> |
21 | #include <linux/string.h> | |
22 | #include <linux/threads.h> | |
23 | #include <linux/parport.h> | |
24 | #include <linux/delay.h> | |
25 | #include <linux/errno.h> | |
26 | #include <linux/interrupt.h> | |
27 | #include <linux/ioport.h> | |
28 | #include <linux/kernel.h> | |
29 | #include <linux/slab.h> | |
30 | #include <linux/sched.h> | |
31 | #include <linux/kmod.h> | |
32 | ||
33 | #include <linux/spinlock.h> | |
14cc3e2b | 34 | #include <linux/mutex.h> |
1da177e4 LT |
35 | #include <asm/irq.h> |
36 | ||
37 | #undef PARPORT_PARANOID | |
38 | ||
39 | #define PARPORT_DEFAULT_TIMESLICE (HZ/5) | |
40 | ||
41 | unsigned long parport_default_timeslice = PARPORT_DEFAULT_TIMESLICE; | |
42 | int parport_default_spintime = DEFAULT_SPIN_TIME; | |
43 | ||
44 | static LIST_HEAD(portlist); | |
45 | static DEFINE_SPINLOCK(parportlist_lock); | |
46 | ||
47 | /* list of all allocated ports, sorted by ->number */ | |
48 | static LIST_HEAD(all_ports); | |
49 | static DEFINE_SPINLOCK(full_list_lock); | |
50 | ||
51 | static LIST_HEAD(drivers); | |
52 | ||
14cc3e2b | 53 | static DEFINE_MUTEX(registration_lock); |
1da177e4 LT |
54 | |
55 | /* What you can do to a port that's gone away.. */ | |
56 | static void dead_write_lines (struct parport *p, unsigned char b){} | |
57 | static unsigned char dead_read_lines (struct parport *p) { return 0; } | |
58 | static unsigned char dead_frob_lines (struct parport *p, unsigned char b, | |
59 | unsigned char c) { return 0; } | |
60 | static void dead_onearg (struct parport *p){} | |
61 | static void dead_initstate (struct pardevice *d, struct parport_state *s) { } | |
62 | static void dead_state (struct parport *p, struct parport_state *s) { } | |
63 | static size_t dead_write (struct parport *p, const void *b, size_t l, int f) | |
64 | { return 0; } | |
65 | static size_t dead_read (struct parport *p, void *b, size_t l, int f) | |
66 | { return 0; } | |
67 | static struct parport_operations dead_ops = { | |
68 | .write_data = dead_write_lines, /* data */ | |
69 | .read_data = dead_read_lines, | |
70 | ||
71 | .write_control = dead_write_lines, /* control */ | |
72 | .read_control = dead_read_lines, | |
73 | .frob_control = dead_frob_lines, | |
74 | ||
75 | .read_status = dead_read_lines, /* status */ | |
76 | ||
77 | .enable_irq = dead_onearg, /* enable_irq */ | |
78 | .disable_irq = dead_onearg, /* disable_irq */ | |
79 | ||
80 | .data_forward = dead_onearg, /* data_forward */ | |
81 | .data_reverse = dead_onearg, /* data_reverse */ | |
82 | ||
83 | .init_state = dead_initstate, /* init_state */ | |
84 | .save_state = dead_state, | |
85 | .restore_state = dead_state, | |
86 | ||
87 | .epp_write_data = dead_write, /* epp */ | |
88 | .epp_read_data = dead_read, | |
89 | .epp_write_addr = dead_write, | |
90 | .epp_read_addr = dead_read, | |
91 | ||
92 | .ecp_write_data = dead_write, /* ecp */ | |
93 | .ecp_read_data = dead_read, | |
94 | .ecp_write_addr = dead_write, | |
95 | ||
96 | .compat_write_data = dead_write, /* compat */ | |
97 | .nibble_read_data = dead_read, /* nibble */ | |
98 | .byte_read_data = dead_read, /* byte */ | |
99 | ||
100 | .owner = NULL, | |
101 | }; | |
102 | ||
103 | /* Call attach(port) for each registered driver. */ | |
104 | static void attach_driver_chain(struct parport *port) | |
105 | { | |
106 | /* caller has exclusive registration_lock */ | |
107 | struct parport_driver *drv; | |
108 | list_for_each_entry(drv, &drivers, list) | |
109 | drv->attach(port); | |
110 | } | |
111 | ||
112 | /* Call detach(port) for each registered driver. */ | |
113 | static void detach_driver_chain(struct parport *port) | |
114 | { | |
115 | struct parport_driver *drv; | |
116 | /* caller has exclusive registration_lock */ | |
117 | list_for_each_entry(drv, &drivers, list) | |
118 | drv->detach (port); | |
119 | } | |
120 | ||
121 | /* Ask kmod for some lowlevel drivers. */ | |
122 | static void get_lowlevel_driver (void) | |
123 | { | |
124 | /* There is no actual module called this: you should set | |
125 | * up an alias for modutils. */ | |
126 | request_module ("parport_lowlevel"); | |
127 | } | |
128 | ||
129 | /** | |
130 | * parport_register_driver - register a parallel port device driver | |
131 | * @drv: structure describing the driver | |
132 | * | |
133 | * This can be called by a parallel port device driver in order | |
134 | * to receive notifications about ports being found in the | |
135 | * system, as well as ports no longer available. | |
136 | * | |
137 | * The @drv structure is allocated by the caller and must not be | |
138 | * deallocated until after calling parport_unregister_driver(). | |
139 | * | |
140 | * The driver's attach() function may block. The port that | |
141 | * attach() is given will be valid for the duration of the | |
142 | * callback, but if the driver wants to take a copy of the | |
143 | * pointer it must call parport_get_port() to do so. Calling | |
144 | * parport_register_device() on that port will do this for you. | |
145 | * | |
146 | * The driver's detach() function may block. The port that | |
147 | * detach() is given will be valid for the duration of the | |
148 | * callback, but if the driver wants to take a copy of the | |
149 | * pointer it must call parport_get_port() to do so. | |
150 | * | |
151 | * Returns 0 on success. Currently it always succeeds. | |
152 | **/ | |
153 | ||
154 | int parport_register_driver (struct parport_driver *drv) | |
155 | { | |
156 | struct parport *port; | |
157 | ||
158 | if (list_empty(&portlist)) | |
159 | get_lowlevel_driver (); | |
160 | ||
14cc3e2b | 161 | mutex_lock(®istration_lock); |
1da177e4 LT |
162 | list_for_each_entry(port, &portlist, list) |
163 | drv->attach(port); | |
164 | list_add(&drv->list, &drivers); | |
14cc3e2b | 165 | mutex_unlock(®istration_lock); |
1da177e4 LT |
166 | |
167 | return 0; | |
168 | } | |
169 | ||
170 | /** | |
171 | * parport_unregister_driver - deregister a parallel port device driver | |
172 | * @drv: structure describing the driver that was given to | |
173 | * parport_register_driver() | |
174 | * | |
175 | * This should be called by a parallel port device driver that | |
176 | * has registered itself using parport_register_driver() when it | |
177 | * is about to be unloaded. | |
178 | * | |
179 | * When it returns, the driver's attach() routine will no longer | |
180 | * be called, and for each port that attach() was called for, the | |
181 | * detach() routine will have been called. | |
182 | * | |
183 | * All the driver's attach() and detach() calls are guaranteed to have | |
184 | * finished by the time this function returns. | |
185 | **/ | |
186 | ||
187 | void parport_unregister_driver (struct parport_driver *drv) | |
188 | { | |
189 | struct parport *port; | |
190 | ||
14cc3e2b | 191 | mutex_lock(®istration_lock); |
1da177e4 LT |
192 | list_del_init(&drv->list); |
193 | list_for_each_entry(port, &portlist, list) | |
194 | drv->detach(port); | |
14cc3e2b | 195 | mutex_unlock(®istration_lock); |
1da177e4 LT |
196 | } |
197 | ||
198 | static void free_port (struct parport *port) | |
199 | { | |
200 | int d; | |
201 | spin_lock(&full_list_lock); | |
202 | list_del(&port->full_list); | |
203 | spin_unlock(&full_list_lock); | |
204 | for (d = 0; d < 5; d++) { | |
6044ec88 JJ |
205 | kfree(port->probe_info[d].class_name); |
206 | kfree(port->probe_info[d].mfr); | |
207 | kfree(port->probe_info[d].model); | |
208 | kfree(port->probe_info[d].cmdset); | |
209 | kfree(port->probe_info[d].description); | |
1da177e4 LT |
210 | } |
211 | ||
212 | kfree(port->name); | |
213 | kfree(port); | |
214 | } | |
215 | ||
216 | /** | |
217 | * parport_get_port - increment a port's reference count | |
218 | * @port: the port | |
219 | * | |
7d469722 | 220 | * This ensures that a struct parport pointer remains valid |
1da177e4 LT |
221 | * until the matching parport_put_port() call. |
222 | **/ | |
223 | ||
224 | struct parport *parport_get_port (struct parport *port) | |
225 | { | |
226 | atomic_inc (&port->ref_count); | |
227 | return port; | |
228 | } | |
229 | ||
230 | /** | |
231 | * parport_put_port - decrement a port's reference count | |
232 | * @port: the port | |
233 | * | |
234 | * This should be called once for each call to parport_get_port(), | |
235 | * once the port is no longer needed. | |
236 | **/ | |
237 | ||
238 | void parport_put_port (struct parport *port) | |
239 | { | |
240 | if (atomic_dec_and_test (&port->ref_count)) | |
241 | /* Can destroy it now. */ | |
242 | free_port (port); | |
243 | ||
244 | return; | |
245 | } | |
246 | ||
247 | /** | |
248 | * parport_register_port - register a parallel port | |
249 | * @base: base I/O address | |
250 | * @irq: IRQ line | |
251 | * @dma: DMA channel | |
252 | * @ops: pointer to the port driver's port operations structure | |
253 | * | |
254 | * When a parallel port (lowlevel) driver finds a port that | |
255 | * should be made available to parallel port device drivers, it | |
256 | * should call parport_register_port(). The @base, @irq, and | |
257 | * @dma parameters are for the convenience of port drivers, and | |
258 | * for ports where they aren't meaningful needn't be set to | |
259 | * anything special. They can be altered afterwards by adjusting | |
260 | * the relevant members of the parport structure that is returned | |
261 | * and represents the port. They should not be tampered with | |
262 | * after calling parport_announce_port, however. | |
263 | * | |
264 | * If there are parallel port device drivers in the system that | |
265 | * have registered themselves using parport_register_driver(), | |
266 | * they are not told about the port at this time; that is done by | |
267 | * parport_announce_port(). | |
268 | * | |
269 | * The @ops structure is allocated by the caller, and must not be | |
270 | * deallocated before calling parport_remove_port(). | |
271 | * | |
272 | * If there is no memory to allocate a new parport structure, | |
273 | * this function will return %NULL. | |
274 | **/ | |
275 | ||
276 | struct parport *parport_register_port(unsigned long base, int irq, int dma, | |
277 | struct parport_operations *ops) | |
278 | { | |
279 | struct list_head *l; | |
280 | struct parport *tmp; | |
281 | int num; | |
282 | int device; | |
283 | char *name; | |
284 | ||
285 | tmp = kmalloc(sizeof(struct parport), GFP_KERNEL); | |
286 | if (!tmp) { | |
287 | printk(KERN_WARNING "parport: memory squeeze\n"); | |
288 | return NULL; | |
289 | } | |
290 | ||
291 | /* Init our structure */ | |
292 | memset(tmp, 0, sizeof(struct parport)); | |
293 | tmp->base = base; | |
294 | tmp->irq = irq; | |
295 | tmp->dma = dma; | |
296 | tmp->muxport = tmp->daisy = tmp->muxsel = -1; | |
297 | tmp->modes = 0; | |
298 | INIT_LIST_HEAD(&tmp->list); | |
299 | tmp->devices = tmp->cad = NULL; | |
300 | tmp->flags = 0; | |
301 | tmp->ops = ops; | |
302 | tmp->physport = tmp; | |
303 | memset (tmp->probe_info, 0, 5 * sizeof (struct parport_device_info)); | |
304 | rwlock_init(&tmp->cad_lock); | |
305 | spin_lock_init(&tmp->waitlist_lock); | |
306 | spin_lock_init(&tmp->pardevice_lock); | |
307 | tmp->ieee1284.mode = IEEE1284_MODE_COMPAT; | |
308 | tmp->ieee1284.phase = IEEE1284_PH_FWD_IDLE; | |
309 | init_MUTEX_LOCKED (&tmp->ieee1284.irq); /* actually a semaphore at 0 */ | |
310 | tmp->spintime = parport_default_spintime; | |
311 | atomic_set (&tmp->ref_count, 1); | |
312 | INIT_LIST_HEAD(&tmp->full_list); | |
313 | ||
314 | name = kmalloc(15, GFP_KERNEL); | |
315 | if (!name) { | |
316 | printk(KERN_ERR "parport: memory squeeze\n"); | |
317 | kfree(tmp); | |
318 | return NULL; | |
319 | } | |
320 | /* Search for the lowest free parport number. */ | |
321 | ||
322 | spin_lock(&full_list_lock); | |
323 | for (l = all_ports.next, num = 0; l != &all_ports; l = l->next, num++) { | |
324 | struct parport *p = list_entry(l, struct parport, full_list); | |
325 | if (p->number != num) | |
326 | break; | |
327 | } | |
328 | tmp->portnum = tmp->number = num; | |
329 | list_add_tail(&tmp->full_list, l); | |
330 | spin_unlock(&full_list_lock); | |
331 | ||
332 | /* | |
333 | * Now that the portnum is known finish doing the Init. | |
334 | */ | |
335 | sprintf(name, "parport%d", tmp->portnum = tmp->number); | |
336 | tmp->name = name; | |
337 | ||
338 | for (device = 0; device < 5; device++) | |
339 | /* assume the worst */ | |
340 | tmp->probe_info[device].class = PARPORT_CLASS_LEGACY; | |
341 | ||
342 | tmp->waithead = tmp->waittail = NULL; | |
343 | ||
344 | return tmp; | |
345 | } | |
346 | ||
347 | /** | |
348 | * parport_announce_port - tell device drivers about a parallel port | |
349 | * @port: parallel port to announce | |
350 | * | |
351 | * After a port driver has registered a parallel port with | |
352 | * parport_register_port, and performed any necessary | |
353 | * initialisation or adjustments, it should call | |
354 | * parport_announce_port() in order to notify all device drivers | |
355 | * that have called parport_register_driver(). Their attach() | |
356 | * functions will be called, with @port as the parameter. | |
357 | **/ | |
358 | ||
359 | void parport_announce_port (struct parport *port) | |
360 | { | |
361 | int i; | |
362 | ||
363 | #ifdef CONFIG_PARPORT_1284 | |
364 | /* Analyse the IEEE1284.3 topology of the port. */ | |
365 | parport_daisy_init(port); | |
366 | #endif | |
367 | ||
368 | parport_proc_register(port); | |
14cc3e2b | 369 | mutex_lock(®istration_lock); |
1da177e4 LT |
370 | spin_lock_irq(&parportlist_lock); |
371 | list_add_tail(&port->list, &portlist); | |
372 | for (i = 1; i < 3; i++) { | |
373 | struct parport *slave = port->slaves[i-1]; | |
374 | if (slave) | |
375 | list_add_tail(&slave->list, &portlist); | |
376 | } | |
377 | spin_unlock_irq(&parportlist_lock); | |
378 | ||
379 | /* Let drivers know that new port(s) has arrived. */ | |
380 | attach_driver_chain (port); | |
381 | for (i = 1; i < 3; i++) { | |
382 | struct parport *slave = port->slaves[i-1]; | |
383 | if (slave) | |
384 | attach_driver_chain(slave); | |
385 | } | |
14cc3e2b | 386 | mutex_unlock(®istration_lock); |
1da177e4 LT |
387 | } |
388 | ||
389 | /** | |
390 | * parport_remove_port - deregister a parallel port | |
391 | * @port: parallel port to deregister | |
392 | * | |
393 | * When a parallel port driver is forcibly unloaded, or a | |
394 | * parallel port becomes inaccessible, the port driver must call | |
395 | * this function in order to deal with device drivers that still | |
396 | * want to use it. | |
397 | * | |
398 | * The parport structure associated with the port has its | |
399 | * operations structure replaced with one containing 'null' | |
400 | * operations that return errors or just don't do anything. | |
401 | * | |
402 | * Any drivers that have registered themselves using | |
403 | * parport_register_driver() are notified that the port is no | |
404 | * longer accessible by having their detach() routines called | |
405 | * with @port as the parameter. | |
406 | **/ | |
407 | ||
408 | void parport_remove_port(struct parport *port) | |
409 | { | |
410 | int i; | |
411 | ||
14cc3e2b | 412 | mutex_lock(®istration_lock); |
1da177e4 LT |
413 | |
414 | /* Spread the word. */ | |
415 | detach_driver_chain (port); | |
416 | ||
417 | #ifdef CONFIG_PARPORT_1284 | |
418 | /* Forget the IEEE1284.3 topology of the port. */ | |
419 | parport_daisy_fini(port); | |
420 | for (i = 1; i < 3; i++) { | |
421 | struct parport *slave = port->slaves[i-1]; | |
422 | if (!slave) | |
423 | continue; | |
424 | detach_driver_chain(slave); | |
425 | parport_daisy_fini(slave); | |
426 | } | |
427 | #endif | |
428 | ||
429 | port->ops = &dead_ops; | |
430 | spin_lock(&parportlist_lock); | |
431 | list_del_init(&port->list); | |
432 | for (i = 1; i < 3; i++) { | |
433 | struct parport *slave = port->slaves[i-1]; | |
434 | if (slave) | |
435 | list_del_init(&slave->list); | |
436 | } | |
437 | spin_unlock(&parportlist_lock); | |
438 | ||
14cc3e2b | 439 | mutex_unlock(®istration_lock); |
1da177e4 LT |
440 | |
441 | parport_proc_unregister(port); | |
442 | ||
443 | for (i = 1; i < 3; i++) { | |
444 | struct parport *slave = port->slaves[i-1]; | |
445 | if (slave) | |
446 | parport_put_port(slave); | |
447 | } | |
448 | } | |
449 | ||
450 | /** | |
451 | * parport_register_device - register a device on a parallel port | |
452 | * @port: port to which the device is attached | |
453 | * @name: a name to refer to the device | |
454 | * @pf: preemption callback | |
455 | * @kf: kick callback (wake-up) | |
456 | * @irq_func: interrupt handler | |
457 | * @flags: registration flags | |
458 | * @handle: data for callback functions | |
459 | * | |
460 | * This function, called by parallel port device drivers, | |
461 | * declares that a device is connected to a port, and tells the | |
462 | * system all it needs to know. | |
463 | * | |
464 | * The @name is allocated by the caller and must not be | |
465 | * deallocated until the caller calls @parport_unregister_device | |
466 | * for that device. | |
467 | * | |
468 | * The preemption callback function, @pf, is called when this | |
469 | * device driver has claimed access to the port but another | |
470 | * device driver wants to use it. It is given @handle as its | |
471 | * parameter, and should return zero if it is willing for the | |
472 | * system to release the port to another driver on its behalf. | |
473 | * If it wants to keep control of the port it should return | |
474 | * non-zero, and no action will be taken. It is good manners for | |
475 | * the driver to try to release the port at the earliest | |
476 | * opportunity after its preemption callback rejects a preemption | |
477 | * attempt. Note that if a preemption callback is happy for | |
478 | * preemption to go ahead, there is no need to release the port; | |
479 | * it is done automatically. This function may not block, as it | |
480 | * may be called from interrupt context. If the device driver | |
481 | * does not support preemption, @pf can be %NULL. | |
482 | * | |
483 | * The wake-up ("kick") callback function, @kf, is called when | |
484 | * the port is available to be claimed for exclusive access; that | |
485 | * is, parport_claim() is guaranteed to succeed when called from | |
486 | * inside the wake-up callback function. If the driver wants to | |
487 | * claim the port it should do so; otherwise, it need not take | |
488 | * any action. This function may not block, as it may be called | |
489 | * from interrupt context. If the device driver does not want to | |
490 | * be explicitly invited to claim the port in this way, @kf can | |
491 | * be %NULL. | |
492 | * | |
493 | * The interrupt handler, @irq_func, is called when an interrupt | |
494 | * arrives from the parallel port. Note that if a device driver | |
495 | * wants to use interrupts it should use parport_enable_irq(), | |
496 | * and can also check the irq member of the parport structure | |
497 | * representing the port. | |
498 | * | |
499 | * The parallel port (lowlevel) driver is the one that has called | |
500 | * request_irq() and whose interrupt handler is called first. | |
501 | * This handler does whatever needs to be done to the hardware to | |
502 | * acknowledge the interrupt (for PC-style ports there is nothing | |
503 | * special to be done). It then tells the IEEE 1284 code about | |
504 | * the interrupt, which may involve reacting to an IEEE 1284 | |
505 | * event depending on the current IEEE 1284 phase. After this, | |
506 | * it calls @irq_func. Needless to say, @irq_func will be called | |
507 | * from interrupt context, and may not block. | |
508 | * | |
509 | * The %PARPORT_DEV_EXCL flag is for preventing port sharing, and | |
510 | * so should only be used when sharing the port with other device | |
511 | * drivers is impossible and would lead to incorrect behaviour. | |
512 | * Use it sparingly! Normally, @flags will be zero. | |
513 | * | |
514 | * This function returns a pointer to a structure that represents | |
515 | * the device on the port, or %NULL if there is not enough memory | |
516 | * to allocate space for that structure. | |
517 | **/ | |
518 | ||
519 | struct pardevice * | |
520 | parport_register_device(struct parport *port, const char *name, | |
521 | int (*pf)(void *), void (*kf)(void *), | |
522 | void (*irq_func)(int, void *, struct pt_regs *), | |
523 | int flags, void *handle) | |
524 | { | |
525 | struct pardevice *tmp; | |
526 | ||
527 | if (port->physport->flags & PARPORT_FLAG_EXCL) { | |
528 | /* An exclusive device is registered. */ | |
529 | printk (KERN_DEBUG "%s: no more devices allowed\n", | |
530 | port->name); | |
531 | return NULL; | |
532 | } | |
533 | ||
534 | if (flags & PARPORT_DEV_LURK) { | |
535 | if (!pf || !kf) { | |
536 | printk(KERN_INFO "%s: refused to register lurking device (%s) without callbacks\n", port->name, name); | |
537 | return NULL; | |
538 | } | |
539 | } | |
540 | ||
541 | /* We up our own module reference count, and that of the port | |
542 | on which a device is to be registered, to ensure that | |
543 | neither of us gets unloaded while we sleep in (e.g.) | |
544 | kmalloc. | |
545 | */ | |
546 | if (!try_module_get(port->ops->owner)) { | |
547 | return NULL; | |
548 | } | |
549 | ||
550 | parport_get_port (port); | |
551 | ||
552 | tmp = kmalloc(sizeof(struct pardevice), GFP_KERNEL); | |
553 | if (tmp == NULL) { | |
554 | printk(KERN_WARNING "%s: memory squeeze, couldn't register %s.\n", port->name, name); | |
555 | goto out; | |
556 | } | |
557 | ||
558 | tmp->state = kmalloc(sizeof(struct parport_state), GFP_KERNEL); | |
559 | if (tmp->state == NULL) { | |
560 | printk(KERN_WARNING "%s: memory squeeze, couldn't register %s.\n", port->name, name); | |
561 | goto out_free_pardevice; | |
562 | } | |
563 | ||
564 | tmp->name = name; | |
565 | tmp->port = port; | |
566 | tmp->daisy = -1; | |
567 | tmp->preempt = pf; | |
568 | tmp->wakeup = kf; | |
569 | tmp->private = handle; | |
570 | tmp->flags = flags; | |
571 | tmp->irq_func = irq_func; | |
572 | tmp->waiting = 0; | |
573 | tmp->timeout = 5 * HZ; | |
574 | ||
575 | /* Chain this onto the list */ | |
576 | tmp->prev = NULL; | |
577 | /* | |
578 | * This function must not run from an irq handler so we don' t need | |
579 | * to clear irq on the local CPU. -arca | |
580 | */ | |
581 | spin_lock(&port->physport->pardevice_lock); | |
582 | ||
583 | if (flags & PARPORT_DEV_EXCL) { | |
584 | if (port->physport->devices) { | |
585 | spin_unlock (&port->physport->pardevice_lock); | |
586 | printk (KERN_DEBUG | |
587 | "%s: cannot grant exclusive access for " | |
588 | "device %s\n", port->name, name); | |
589 | goto out_free_all; | |
590 | } | |
591 | port->flags |= PARPORT_FLAG_EXCL; | |
592 | } | |
593 | ||
594 | tmp->next = port->physport->devices; | |
595 | wmb(); /* Make sure that tmp->next is written before it's | |
596 | added to the list; see comments marked 'no locking | |
597 | required' */ | |
598 | if (port->physport->devices) | |
599 | port->physport->devices->prev = tmp; | |
600 | port->physport->devices = tmp; | |
601 | spin_unlock(&port->physport->pardevice_lock); | |
602 | ||
603 | init_waitqueue_head(&tmp->wait_q); | |
604 | tmp->timeslice = parport_default_timeslice; | |
605 | tmp->waitnext = tmp->waitprev = NULL; | |
606 | ||
607 | /* | |
608 | * This has to be run as last thing since init_state may need other | |
609 | * pardevice fields. -arca | |
610 | */ | |
611 | port->ops->init_state(tmp, tmp->state); | |
612 | parport_device_proc_register(tmp); | |
613 | return tmp; | |
614 | ||
615 | out_free_all: | |
6044ec88 | 616 | kfree(tmp->state); |
1da177e4 | 617 | out_free_pardevice: |
6044ec88 | 618 | kfree(tmp); |
1da177e4 LT |
619 | out: |
620 | parport_put_port (port); | |
621 | module_put(port->ops->owner); | |
622 | ||
623 | return NULL; | |
624 | } | |
625 | ||
626 | /** | |
627 | * parport_unregister_device - deregister a device on a parallel port | |
628 | * @dev: pointer to structure representing device | |
629 | * | |
630 | * This undoes the effect of parport_register_device(). | |
631 | **/ | |
632 | ||
633 | void parport_unregister_device(struct pardevice *dev) | |
634 | { | |
635 | struct parport *port; | |
636 | ||
637 | #ifdef PARPORT_PARANOID | |
638 | if (dev == NULL) { | |
639 | printk(KERN_ERR "parport_unregister_device: passed NULL\n"); | |
640 | return; | |
641 | } | |
642 | #endif | |
643 | ||
644 | parport_device_proc_unregister(dev); | |
645 | ||
646 | port = dev->port->physport; | |
647 | ||
648 | if (port->cad == dev) { | |
649 | printk(KERN_DEBUG "%s: %s forgot to release port\n", | |
650 | port->name, dev->name); | |
651 | parport_release (dev); | |
652 | } | |
653 | ||
654 | spin_lock(&port->pardevice_lock); | |
655 | if (dev->next) | |
656 | dev->next->prev = dev->prev; | |
657 | if (dev->prev) | |
658 | dev->prev->next = dev->next; | |
659 | else | |
660 | port->devices = dev->next; | |
661 | ||
662 | if (dev->flags & PARPORT_DEV_EXCL) | |
663 | port->flags &= ~PARPORT_FLAG_EXCL; | |
664 | ||
665 | spin_unlock(&port->pardevice_lock); | |
666 | ||
667 | /* Make sure we haven't left any pointers around in the wait | |
668 | * list. */ | |
669 | spin_lock (&port->waitlist_lock); | |
670 | if (dev->waitprev || dev->waitnext || port->waithead == dev) { | |
671 | if (dev->waitprev) | |
672 | dev->waitprev->waitnext = dev->waitnext; | |
673 | else | |
674 | port->waithead = dev->waitnext; | |
675 | if (dev->waitnext) | |
676 | dev->waitnext->waitprev = dev->waitprev; | |
677 | else | |
678 | port->waittail = dev->waitprev; | |
679 | } | |
680 | spin_unlock (&port->waitlist_lock); | |
681 | ||
682 | kfree(dev->state); | |
683 | kfree(dev); | |
684 | ||
685 | module_put(port->ops->owner); | |
686 | parport_put_port (port); | |
687 | } | |
688 | ||
689 | /** | |
690 | * parport_find_number - find a parallel port by number | |
691 | * @number: parallel port number | |
692 | * | |
693 | * This returns the parallel port with the specified number, or | |
694 | * %NULL if there is none. | |
695 | * | |
696 | * There is an implicit parport_get_port() done already; to throw | |
697 | * away the reference to the port that parport_find_number() | |
698 | * gives you, use parport_put_port(). | |
699 | */ | |
700 | ||
701 | struct parport *parport_find_number (int number) | |
702 | { | |
703 | struct parport *port, *result = NULL; | |
704 | ||
705 | if (list_empty(&portlist)) | |
706 | get_lowlevel_driver (); | |
707 | ||
708 | spin_lock (&parportlist_lock); | |
709 | list_for_each_entry(port, &portlist, list) { | |
710 | if (port->number == number) { | |
711 | result = parport_get_port (port); | |
712 | break; | |
713 | } | |
714 | } | |
715 | spin_unlock (&parportlist_lock); | |
716 | return result; | |
717 | } | |
718 | ||
719 | /** | |
720 | * parport_find_base - find a parallel port by base address | |
721 | * @base: base I/O address | |
722 | * | |
723 | * This returns the parallel port with the specified base | |
724 | * address, or %NULL if there is none. | |
725 | * | |
726 | * There is an implicit parport_get_port() done already; to throw | |
727 | * away the reference to the port that parport_find_base() | |
728 | * gives you, use parport_put_port(). | |
729 | */ | |
730 | ||
731 | struct parport *parport_find_base (unsigned long base) | |
732 | { | |
733 | struct parport *port, *result = NULL; | |
734 | ||
735 | if (list_empty(&portlist)) | |
736 | get_lowlevel_driver (); | |
737 | ||
738 | spin_lock (&parportlist_lock); | |
739 | list_for_each_entry(port, &portlist, list) { | |
740 | if (port->base == base) { | |
741 | result = parport_get_port (port); | |
742 | break; | |
743 | } | |
744 | } | |
745 | spin_unlock (&parportlist_lock); | |
746 | return result; | |
747 | } | |
748 | ||
749 | /** | |
750 | * parport_claim - claim access to a parallel port device | |
751 | * @dev: pointer to structure representing a device on the port | |
752 | * | |
753 | * This function will not block and so can be used from interrupt | |
754 | * context. If parport_claim() succeeds in claiming access to | |
755 | * the port it returns zero and the port is available to use. It | |
756 | * may fail (returning non-zero) if the port is in use by another | |
757 | * driver and that driver is not willing to relinquish control of | |
758 | * the port. | |
759 | **/ | |
760 | ||
761 | int parport_claim(struct pardevice *dev) | |
762 | { | |
763 | struct pardevice *oldcad; | |
764 | struct parport *port = dev->port->physport; | |
765 | unsigned long flags; | |
766 | ||
767 | if (port->cad == dev) { | |
768 | printk(KERN_INFO "%s: %s already owner\n", | |
769 | dev->port->name,dev->name); | |
770 | return 0; | |
771 | } | |
772 | ||
773 | /* Preempt any current device */ | |
774 | write_lock_irqsave (&port->cad_lock, flags); | |
775 | if ((oldcad = port->cad) != NULL) { | |
776 | if (oldcad->preempt) { | |
777 | if (oldcad->preempt(oldcad->private)) | |
778 | goto blocked; | |
779 | port->ops->save_state(port, dev->state); | |
780 | } else | |
781 | goto blocked; | |
782 | ||
783 | if (port->cad != oldcad) { | |
784 | /* I think we'll actually deadlock rather than | |
785 | get here, but just in case.. */ | |
786 | printk(KERN_WARNING | |
787 | "%s: %s released port when preempted!\n", | |
788 | port->name, oldcad->name); | |
789 | if (port->cad) | |
790 | goto blocked; | |
791 | } | |
792 | } | |
793 | ||
794 | /* Can't fail from now on, so mark ourselves as no longer waiting. */ | |
795 | if (dev->waiting & 1) { | |
796 | dev->waiting = 0; | |
797 | ||
798 | /* Take ourselves out of the wait list again. */ | |
799 | spin_lock_irq (&port->waitlist_lock); | |
800 | if (dev->waitprev) | |
801 | dev->waitprev->waitnext = dev->waitnext; | |
802 | else | |
803 | port->waithead = dev->waitnext; | |
804 | if (dev->waitnext) | |
805 | dev->waitnext->waitprev = dev->waitprev; | |
806 | else | |
807 | port->waittail = dev->waitprev; | |
808 | spin_unlock_irq (&port->waitlist_lock); | |
809 | dev->waitprev = dev->waitnext = NULL; | |
810 | } | |
811 | ||
812 | /* Now we do the change of devices */ | |
813 | port->cad = dev; | |
814 | ||
815 | #ifdef CONFIG_PARPORT_1284 | |
816 | /* If it's a mux port, select it. */ | |
817 | if (dev->port->muxport >= 0) { | |
818 | /* FIXME */ | |
819 | port->muxsel = dev->port->muxport; | |
820 | } | |
821 | ||
822 | /* If it's a daisy chain device, select it. */ | |
823 | if (dev->daisy >= 0) { | |
824 | /* This could be lazier. */ | |
825 | if (!parport_daisy_select (port, dev->daisy, | |
826 | IEEE1284_MODE_COMPAT)) | |
827 | port->daisy = dev->daisy; | |
828 | } | |
829 | #endif /* IEEE1284.3 support */ | |
830 | ||
831 | /* Restore control registers */ | |
832 | port->ops->restore_state(port, dev->state); | |
833 | write_unlock_irqrestore(&port->cad_lock, flags); | |
834 | dev->time = jiffies; | |
835 | return 0; | |
836 | ||
837 | blocked: | |
838 | /* If this is the first time we tried to claim the port, register an | |
839 | interest. This is only allowed for devices sleeping in | |
840 | parport_claim_or_block(), or those with a wakeup function. */ | |
841 | ||
842 | /* The cad_lock is still held for writing here */ | |
843 | if (dev->waiting & 2 || dev->wakeup) { | |
844 | spin_lock (&port->waitlist_lock); | |
845 | if (test_and_set_bit(0, &dev->waiting) == 0) { | |
846 | /* First add ourselves to the end of the wait list. */ | |
847 | dev->waitnext = NULL; | |
848 | dev->waitprev = port->waittail; | |
849 | if (port->waittail) { | |
850 | port->waittail->waitnext = dev; | |
851 | port->waittail = dev; | |
852 | } else | |
853 | port->waithead = port->waittail = dev; | |
854 | } | |
855 | spin_unlock (&port->waitlist_lock); | |
856 | } | |
857 | write_unlock_irqrestore (&port->cad_lock, flags); | |
858 | return -EAGAIN; | |
859 | } | |
860 | ||
861 | /** | |
862 | * parport_claim_or_block - claim access to a parallel port device | |
863 | * @dev: pointer to structure representing a device on the port | |
864 | * | |
865 | * This behaves like parport_claim(), but will block if necessary | |
866 | * to wait for the port to be free. A return value of 1 | |
867 | * indicates that it slept; 0 means that it succeeded without | |
868 | * needing to sleep. A negative error code indicates failure. | |
869 | **/ | |
870 | ||
871 | int parport_claim_or_block(struct pardevice *dev) | |
872 | { | |
873 | int r; | |
874 | ||
875 | /* Signal to parport_claim() that we can wait even without a | |
876 | wakeup function. */ | |
877 | dev->waiting = 2; | |
878 | ||
879 | /* Try to claim the port. If this fails, we need to sleep. */ | |
880 | r = parport_claim(dev); | |
881 | if (r == -EAGAIN) { | |
882 | #ifdef PARPORT_DEBUG_SHARING | |
883 | printk(KERN_DEBUG "%s: parport_claim() returned -EAGAIN\n", dev->name); | |
884 | #endif | |
885 | /* | |
886 | * FIXME!!! Use the proper locking for dev->waiting, | |
887 | * and make this use the "wait_event_interruptible()" | |
888 | * interfaces. The cli/sti that used to be here | |
889 | * did nothing. | |
890 | * | |
891 | * See also parport_release() | |
892 | */ | |
893 | ||
894 | /* If dev->waiting is clear now, an interrupt | |
895 | gave us the port and we would deadlock if we slept. */ | |
896 | if (dev->waiting) { | |
897 | interruptible_sleep_on (&dev->wait_q); | |
898 | if (signal_pending (current)) { | |
899 | return -EINTR; | |
900 | } | |
901 | r = 1; | |
902 | } else { | |
903 | r = 0; | |
904 | #ifdef PARPORT_DEBUG_SHARING | |
905 | printk(KERN_DEBUG "%s: didn't sleep in parport_claim_or_block()\n", | |
906 | dev->name); | |
907 | #endif | |
908 | } | |
909 | ||
910 | #ifdef PARPORT_DEBUG_SHARING | |
911 | if (dev->port->physport->cad != dev) | |
912 | printk(KERN_DEBUG "%s: exiting parport_claim_or_block " | |
913 | "but %s owns port!\n", dev->name, | |
914 | dev->port->physport->cad ? | |
915 | dev->port->physport->cad->name:"nobody"); | |
916 | #endif | |
917 | } | |
918 | dev->waiting = 0; | |
919 | return r; | |
920 | } | |
921 | ||
922 | /** | |
923 | * parport_release - give up access to a parallel port device | |
924 | * @dev: pointer to structure representing parallel port device | |
925 | * | |
926 | * This function cannot fail, but it should not be called without | |
927 | * the port claimed. Similarly, if the port is already claimed | |
928 | * you should not try claiming it again. | |
929 | **/ | |
930 | ||
931 | void parport_release(struct pardevice *dev) | |
932 | { | |
933 | struct parport *port = dev->port->physport; | |
934 | struct pardevice *pd; | |
935 | unsigned long flags; | |
936 | ||
937 | /* Make sure that dev is the current device */ | |
938 | write_lock_irqsave(&port->cad_lock, flags); | |
939 | if (port->cad != dev) { | |
940 | write_unlock_irqrestore (&port->cad_lock, flags); | |
941 | printk(KERN_WARNING "%s: %s tried to release parport " | |
942 | "when not owner\n", port->name, dev->name); | |
943 | return; | |
944 | } | |
945 | ||
946 | #ifdef CONFIG_PARPORT_1284 | |
947 | /* If this is on a mux port, deselect it. */ | |
948 | if (dev->port->muxport >= 0) { | |
949 | /* FIXME */ | |
950 | port->muxsel = -1; | |
951 | } | |
952 | ||
953 | /* If this is a daisy device, deselect it. */ | |
954 | if (dev->daisy >= 0) { | |
955 | parport_daisy_deselect_all (port); | |
956 | port->daisy = -1; | |
957 | } | |
958 | #endif | |
959 | ||
960 | port->cad = NULL; | |
961 | write_unlock_irqrestore(&port->cad_lock, flags); | |
962 | ||
963 | /* Save control registers */ | |
964 | port->ops->save_state(port, dev->state); | |
965 | ||
966 | /* If anybody is waiting, find out who's been there longest and | |
967 | then wake them up. (Note: no locking required) */ | |
968 | /* !!! LOCKING IS NEEDED HERE */ | |
969 | for (pd = port->waithead; pd; pd = pd->waitnext) { | |
970 | if (pd->waiting & 2) { /* sleeping in claim_or_block */ | |
971 | parport_claim(pd); | |
972 | if (waitqueue_active(&pd->wait_q)) | |
973 | wake_up_interruptible(&pd->wait_q); | |
974 | return; | |
975 | } else if (pd->wakeup) { | |
976 | pd->wakeup(pd->private); | |
977 | if (dev->port->cad) /* racy but no matter */ | |
978 | return; | |
979 | } else { | |
980 | printk(KERN_ERR "%s: don't know how to wake %s\n", port->name, pd->name); | |
981 | } | |
982 | } | |
983 | ||
984 | /* Nobody was waiting, so walk the list to see if anyone is | |
985 | interested in being woken up. (Note: no locking required) */ | |
986 | /* !!! LOCKING IS NEEDED HERE */ | |
987 | for (pd = port->devices; (port->cad == NULL) && pd; pd = pd->next) { | |
988 | if (pd->wakeup && pd != dev) | |
989 | pd->wakeup(pd->private); | |
990 | } | |
991 | } | |
992 | ||
993 | /* Exported symbols for modules. */ | |
994 | ||
995 | EXPORT_SYMBOL(parport_claim); | |
996 | EXPORT_SYMBOL(parport_claim_or_block); | |
997 | EXPORT_SYMBOL(parport_release); | |
998 | EXPORT_SYMBOL(parport_register_port); | |
999 | EXPORT_SYMBOL(parport_announce_port); | |
1000 | EXPORT_SYMBOL(parport_remove_port); | |
1001 | EXPORT_SYMBOL(parport_register_driver); | |
1002 | EXPORT_SYMBOL(parport_unregister_driver); | |
1003 | EXPORT_SYMBOL(parport_register_device); | |
1004 | EXPORT_SYMBOL(parport_unregister_device); | |
94b82095 | 1005 | EXPORT_SYMBOL(parport_get_port); |
1da177e4 LT |
1006 | EXPORT_SYMBOL(parport_put_port); |
1007 | EXPORT_SYMBOL(parport_find_number); | |
1008 | EXPORT_SYMBOL(parport_find_base); | |
1009 | ||
1010 | MODULE_LICENSE("GPL"); |