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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 | ||
20 | #include <linux/config.h> | |
21 | #include <linux/module.h> | |
22 | #include <linux/string.h> | |
23 | #include <linux/threads.h> | |
24 | #include <linux/parport.h> | |
25 | #include <linux/delay.h> | |
26 | #include <linux/errno.h> | |
27 | #include <linux/interrupt.h> | |
28 | #include <linux/ioport.h> | |
29 | #include <linux/kernel.h> | |
30 | #include <linux/slab.h> | |
31 | #include <linux/sched.h> | |
32 | #include <linux/kmod.h> | |
33 | ||
34 | #include <linux/spinlock.h> | |
14cc3e2b | 35 | #include <linux/mutex.h> |
1da177e4 LT |
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 | ||
14cc3e2b | 54 | static DEFINE_MUTEX(registration_lock); |
1da177e4 LT |
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 | /* Call attach(port) for each registered driver. */ | |
105 | static void attach_driver_chain(struct parport *port) | |
106 | { | |
107 | /* caller has exclusive registration_lock */ | |
108 | struct parport_driver *drv; | |
109 | list_for_each_entry(drv, &drivers, list) | |
110 | drv->attach(port); | |
111 | } | |
112 | ||
113 | /* Call detach(port) for each registered driver. */ | |
114 | static void detach_driver_chain(struct parport *port) | |
115 | { | |
116 | struct parport_driver *drv; | |
117 | /* caller has exclusive registration_lock */ | |
118 | list_for_each_entry(drv, &drivers, list) | |
119 | drv->detach (port); | |
120 | } | |
121 | ||
122 | /* Ask kmod for some lowlevel drivers. */ | |
123 | static void get_lowlevel_driver (void) | |
124 | { | |
125 | /* There is no actual module called this: you should set | |
126 | * up an alias for modutils. */ | |
127 | request_module ("parport_lowlevel"); | |
128 | } | |
129 | ||
130 | /** | |
131 | * parport_register_driver - register a parallel port device driver | |
132 | * @drv: structure describing the driver | |
133 | * | |
134 | * This can be called by a parallel port device driver in order | |
135 | * to receive notifications about ports being found in the | |
136 | * system, as well as ports no longer available. | |
137 | * | |
138 | * The @drv structure is allocated by the caller and must not be | |
139 | * deallocated until after calling parport_unregister_driver(). | |
140 | * | |
141 | * The driver's attach() function may block. The port that | |
142 | * attach() is given will be valid for the duration of the | |
143 | * callback, but if the driver wants to take a copy of the | |
144 | * pointer it must call parport_get_port() to do so. Calling | |
145 | * parport_register_device() on that port will do this for you. | |
146 | * | |
147 | * The driver's detach() function may block. The port that | |
148 | * detach() is given will be valid for the duration of the | |
149 | * callback, but if the driver wants to take a copy of the | |
150 | * pointer it must call parport_get_port() to do so. | |
151 | * | |
152 | * Returns 0 on success. Currently it always succeeds. | |
153 | **/ | |
154 | ||
155 | int parport_register_driver (struct parport_driver *drv) | |
156 | { | |
157 | struct parport *port; | |
158 | ||
159 | if (list_empty(&portlist)) | |
160 | get_lowlevel_driver (); | |
161 | ||
14cc3e2b | 162 | mutex_lock(®istration_lock); |
1da177e4 LT |
163 | list_for_each_entry(port, &portlist, list) |
164 | drv->attach(port); | |
165 | list_add(&drv->list, &drivers); | |
14cc3e2b | 166 | mutex_unlock(®istration_lock); |
1da177e4 LT |
167 | |
168 | return 0; | |
169 | } | |
170 | ||
171 | /** | |
172 | * parport_unregister_driver - deregister a parallel port device driver | |
173 | * @drv: structure describing the driver that was given to | |
174 | * parport_register_driver() | |
175 | * | |
176 | * This should be called by a parallel port device driver that | |
177 | * has registered itself using parport_register_driver() when it | |
178 | * is about to be unloaded. | |
179 | * | |
180 | * When it returns, the driver's attach() routine will no longer | |
181 | * be called, and for each port that attach() was called for, the | |
182 | * detach() routine will have been called. | |
183 | * | |
184 | * All the driver's attach() and detach() calls are guaranteed to have | |
185 | * finished by the time this function returns. | |
186 | **/ | |
187 | ||
188 | void parport_unregister_driver (struct parport_driver *drv) | |
189 | { | |
190 | struct parport *port; | |
191 | ||
14cc3e2b | 192 | mutex_lock(®istration_lock); |
1da177e4 LT |
193 | list_del_init(&drv->list); |
194 | list_for_each_entry(port, &portlist, list) | |
195 | drv->detach(port); | |
14cc3e2b | 196 | mutex_unlock(®istration_lock); |
1da177e4 LT |
197 | } |
198 | ||
199 | static void free_port (struct parport *port) | |
200 | { | |
201 | int d; | |
202 | spin_lock(&full_list_lock); | |
203 | list_del(&port->full_list); | |
204 | spin_unlock(&full_list_lock); | |
205 | for (d = 0; d < 5; d++) { | |
6044ec88 JJ |
206 | kfree(port->probe_info[d].class_name); |
207 | kfree(port->probe_info[d].mfr); | |
208 | kfree(port->probe_info[d].model); | |
209 | kfree(port->probe_info[d].cmdset); | |
210 | kfree(port->probe_info[d].description); | |
1da177e4 LT |
211 | } |
212 | ||
213 | kfree(port->name); | |
214 | kfree(port); | |
215 | } | |
216 | ||
217 | /** | |
218 | * parport_get_port - increment a port's reference count | |
219 | * @port: the port | |
220 | * | |
7d469722 | 221 | * This ensures that a struct parport pointer remains valid |
1da177e4 LT |
222 | * until the matching parport_put_port() call. |
223 | **/ | |
224 | ||
225 | struct parport *parport_get_port (struct parport *port) | |
226 | { | |
227 | atomic_inc (&port->ref_count); | |
228 | return port; | |
229 | } | |
230 | ||
231 | /** | |
232 | * parport_put_port - decrement a port's reference count | |
233 | * @port: the port | |
234 | * | |
235 | * This should be called once for each call to parport_get_port(), | |
236 | * once the port is no longer needed. | |
237 | **/ | |
238 | ||
239 | void parport_put_port (struct parport *port) | |
240 | { | |
241 | if (atomic_dec_and_test (&port->ref_count)) | |
242 | /* Can destroy it now. */ | |
243 | free_port (port); | |
244 | ||
245 | return; | |
246 | } | |
247 | ||
248 | /** | |
249 | * parport_register_port - register a parallel port | |
250 | * @base: base I/O address | |
251 | * @irq: IRQ line | |
252 | * @dma: DMA channel | |
253 | * @ops: pointer to the port driver's port operations structure | |
254 | * | |
255 | * When a parallel port (lowlevel) driver finds a port that | |
256 | * should be made available to parallel port device drivers, it | |
257 | * should call parport_register_port(). The @base, @irq, and | |
258 | * @dma parameters are for the convenience of port drivers, and | |
259 | * for ports where they aren't meaningful needn't be set to | |
260 | * anything special. They can be altered afterwards by adjusting | |
261 | * the relevant members of the parport structure that is returned | |
262 | * and represents the port. They should not be tampered with | |
263 | * after calling parport_announce_port, however. | |
264 | * | |
265 | * If there are parallel port device drivers in the system that | |
266 | * have registered themselves using parport_register_driver(), | |
267 | * they are not told about the port at this time; that is done by | |
268 | * parport_announce_port(). | |
269 | * | |
270 | * The @ops structure is allocated by the caller, and must not be | |
271 | * deallocated before calling parport_remove_port(). | |
272 | * | |
273 | * If there is no memory to allocate a new parport structure, | |
274 | * this function will return %NULL. | |
275 | **/ | |
276 | ||
277 | struct parport *parport_register_port(unsigned long base, int irq, int dma, | |
278 | struct parport_operations *ops) | |
279 | { | |
280 | struct list_head *l; | |
281 | struct parport *tmp; | |
282 | int num; | |
283 | int device; | |
284 | char *name; | |
285 | ||
286 | tmp = kmalloc(sizeof(struct parport), GFP_KERNEL); | |
287 | if (!tmp) { | |
288 | printk(KERN_WARNING "parport: memory squeeze\n"); | |
289 | return NULL; | |
290 | } | |
291 | ||
292 | /* Init our structure */ | |
293 | memset(tmp, 0, sizeof(struct parport)); | |
294 | tmp->base = base; | |
295 | tmp->irq = irq; | |
296 | tmp->dma = dma; | |
297 | tmp->muxport = tmp->daisy = tmp->muxsel = -1; | |
298 | tmp->modes = 0; | |
299 | INIT_LIST_HEAD(&tmp->list); | |
300 | tmp->devices = tmp->cad = NULL; | |
301 | tmp->flags = 0; | |
302 | tmp->ops = ops; | |
303 | tmp->physport = tmp; | |
304 | memset (tmp->probe_info, 0, 5 * sizeof (struct parport_device_info)); | |
305 | rwlock_init(&tmp->cad_lock); | |
306 | spin_lock_init(&tmp->waitlist_lock); | |
307 | spin_lock_init(&tmp->pardevice_lock); | |
308 | tmp->ieee1284.mode = IEEE1284_MODE_COMPAT; | |
309 | tmp->ieee1284.phase = IEEE1284_PH_FWD_IDLE; | |
310 | init_MUTEX_LOCKED (&tmp->ieee1284.irq); /* actually a semaphore at 0 */ | |
311 | tmp->spintime = parport_default_spintime; | |
312 | atomic_set (&tmp->ref_count, 1); | |
313 | INIT_LIST_HEAD(&tmp->full_list); | |
314 | ||
315 | name = kmalloc(15, GFP_KERNEL); | |
316 | if (!name) { | |
317 | printk(KERN_ERR "parport: memory squeeze\n"); | |
318 | kfree(tmp); | |
319 | return NULL; | |
320 | } | |
321 | /* Search for the lowest free parport number. */ | |
322 | ||
323 | spin_lock(&full_list_lock); | |
324 | for (l = all_ports.next, num = 0; l != &all_ports; l = l->next, num++) { | |
325 | struct parport *p = list_entry(l, struct parport, full_list); | |
326 | if (p->number != num) | |
327 | break; | |
328 | } | |
329 | tmp->portnum = tmp->number = num; | |
330 | list_add_tail(&tmp->full_list, l); | |
331 | spin_unlock(&full_list_lock); | |
332 | ||
333 | /* | |
334 | * Now that the portnum is known finish doing the Init. | |
335 | */ | |
336 | sprintf(name, "parport%d", tmp->portnum = tmp->number); | |
337 | tmp->name = name; | |
338 | ||
339 | for (device = 0; device < 5; device++) | |
340 | /* assume the worst */ | |
341 | tmp->probe_info[device].class = PARPORT_CLASS_LEGACY; | |
342 | ||
343 | tmp->waithead = tmp->waittail = NULL; | |
344 | ||
345 | return tmp; | |
346 | } | |
347 | ||
348 | /** | |
349 | * parport_announce_port - tell device drivers about a parallel port | |
350 | * @port: parallel port to announce | |
351 | * | |
352 | * After a port driver has registered a parallel port with | |
353 | * parport_register_port, and performed any necessary | |
354 | * initialisation or adjustments, it should call | |
355 | * parport_announce_port() in order to notify all device drivers | |
356 | * that have called parport_register_driver(). Their attach() | |
357 | * functions will be called, with @port as the parameter. | |
358 | **/ | |
359 | ||
360 | void parport_announce_port (struct parport *port) | |
361 | { | |
362 | int i; | |
363 | ||
364 | #ifdef CONFIG_PARPORT_1284 | |
365 | /* Analyse the IEEE1284.3 topology of the port. */ | |
366 | parport_daisy_init(port); | |
367 | #endif | |
368 | ||
369 | parport_proc_register(port); | |
14cc3e2b | 370 | mutex_lock(®istration_lock); |
1da177e4 LT |
371 | spin_lock_irq(&parportlist_lock); |
372 | list_add_tail(&port->list, &portlist); | |
373 | for (i = 1; i < 3; i++) { | |
374 | struct parport *slave = port->slaves[i-1]; | |
375 | if (slave) | |
376 | list_add_tail(&slave->list, &portlist); | |
377 | } | |
378 | spin_unlock_irq(&parportlist_lock); | |
379 | ||
380 | /* Let drivers know that new port(s) has arrived. */ | |
381 | attach_driver_chain (port); | |
382 | for (i = 1; i < 3; i++) { | |
383 | struct parport *slave = port->slaves[i-1]; | |
384 | if (slave) | |
385 | attach_driver_chain(slave); | |
386 | } | |
14cc3e2b | 387 | mutex_unlock(®istration_lock); |
1da177e4 LT |
388 | } |
389 | ||
390 | /** | |
391 | * parport_remove_port - deregister a parallel port | |
392 | * @port: parallel port to deregister | |
393 | * | |
394 | * When a parallel port driver is forcibly unloaded, or a | |
395 | * parallel port becomes inaccessible, the port driver must call | |
396 | * this function in order to deal with device drivers that still | |
397 | * want to use it. | |
398 | * | |
399 | * The parport structure associated with the port has its | |
400 | * operations structure replaced with one containing 'null' | |
401 | * operations that return errors or just don't do anything. | |
402 | * | |
403 | * Any drivers that have registered themselves using | |
404 | * parport_register_driver() are notified that the port is no | |
405 | * longer accessible by having their detach() routines called | |
406 | * with @port as the parameter. | |
407 | **/ | |
408 | ||
409 | void parport_remove_port(struct parport *port) | |
410 | { | |
411 | int i; | |
412 | ||
14cc3e2b | 413 | mutex_lock(®istration_lock); |
1da177e4 LT |
414 | |
415 | /* Spread the word. */ | |
416 | detach_driver_chain (port); | |
417 | ||
418 | #ifdef CONFIG_PARPORT_1284 | |
419 | /* Forget the IEEE1284.3 topology of the port. */ | |
420 | parport_daisy_fini(port); | |
421 | for (i = 1; i < 3; i++) { | |
422 | struct parport *slave = port->slaves[i-1]; | |
423 | if (!slave) | |
424 | continue; | |
425 | detach_driver_chain(slave); | |
426 | parport_daisy_fini(slave); | |
427 | } | |
428 | #endif | |
429 | ||
430 | port->ops = &dead_ops; | |
431 | spin_lock(&parportlist_lock); | |
432 | list_del_init(&port->list); | |
433 | for (i = 1; i < 3; i++) { | |
434 | struct parport *slave = port->slaves[i-1]; | |
435 | if (slave) | |
436 | list_del_init(&slave->list); | |
437 | } | |
438 | spin_unlock(&parportlist_lock); | |
439 | ||
14cc3e2b | 440 | mutex_unlock(®istration_lock); |
1da177e4 LT |
441 | |
442 | parport_proc_unregister(port); | |
443 | ||
444 | for (i = 1; i < 3; i++) { | |
445 | struct parport *slave = port->slaves[i-1]; | |
446 | if (slave) | |
447 | parport_put_port(slave); | |
448 | } | |
449 | } | |
450 | ||
451 | /** | |
452 | * parport_register_device - register a device on a parallel port | |
453 | * @port: port to which the device is attached | |
454 | * @name: a name to refer to the device | |
455 | * @pf: preemption callback | |
456 | * @kf: kick callback (wake-up) | |
457 | * @irq_func: interrupt handler | |
458 | * @flags: registration flags | |
459 | * @handle: data for callback functions | |
460 | * | |
461 | * This function, called by parallel port device drivers, | |
462 | * declares that a device is connected to a port, and tells the | |
463 | * system all it needs to know. | |
464 | * | |
465 | * The @name is allocated by the caller and must not be | |
466 | * deallocated until the caller calls @parport_unregister_device | |
467 | * for that device. | |
468 | * | |
469 | * The preemption callback function, @pf, is called when this | |
470 | * device driver has claimed access to the port but another | |
471 | * device driver wants to use it. It is given @handle as its | |
472 | * parameter, and should return zero if it is willing for the | |
473 | * system to release the port to another driver on its behalf. | |
474 | * If it wants to keep control of the port it should return | |
475 | * non-zero, and no action will be taken. It is good manners for | |
476 | * the driver to try to release the port at the earliest | |
477 | * opportunity after its preemption callback rejects a preemption | |
478 | * attempt. Note that if a preemption callback is happy for | |
479 | * preemption to go ahead, there is no need to release the port; | |
480 | * it is done automatically. This function may not block, as it | |
481 | * may be called from interrupt context. If the device driver | |
482 | * does not support preemption, @pf can be %NULL. | |
483 | * | |
484 | * The wake-up ("kick") callback function, @kf, is called when | |
485 | * the port is available to be claimed for exclusive access; that | |
486 | * is, parport_claim() is guaranteed to succeed when called from | |
487 | * inside the wake-up callback function. If the driver wants to | |
488 | * claim the port it should do so; otherwise, it need not take | |
489 | * any action. This function may not block, as it may be called | |
490 | * from interrupt context. If the device driver does not want to | |
491 | * be explicitly invited to claim the port in this way, @kf can | |
492 | * be %NULL. | |
493 | * | |
494 | * The interrupt handler, @irq_func, is called when an interrupt | |
495 | * arrives from the parallel port. Note that if a device driver | |
496 | * wants to use interrupts it should use parport_enable_irq(), | |
497 | * and can also check the irq member of the parport structure | |
498 | * representing the port. | |
499 | * | |
500 | * The parallel port (lowlevel) driver is the one that has called | |
501 | * request_irq() and whose interrupt handler is called first. | |
502 | * This handler does whatever needs to be done to the hardware to | |
503 | * acknowledge the interrupt (for PC-style ports there is nothing | |
504 | * special to be done). It then tells the IEEE 1284 code about | |
505 | * the interrupt, which may involve reacting to an IEEE 1284 | |
506 | * event depending on the current IEEE 1284 phase. After this, | |
507 | * it calls @irq_func. Needless to say, @irq_func will be called | |
508 | * from interrupt context, and may not block. | |
509 | * | |
510 | * The %PARPORT_DEV_EXCL flag is for preventing port sharing, and | |
511 | * so should only be used when sharing the port with other device | |
512 | * drivers is impossible and would lead to incorrect behaviour. | |
513 | * Use it sparingly! Normally, @flags will be zero. | |
514 | * | |
515 | * This function returns a pointer to a structure that represents | |
516 | * the device on the port, or %NULL if there is not enough memory | |
517 | * to allocate space for that structure. | |
518 | **/ | |
519 | ||
520 | struct pardevice * | |
521 | parport_register_device(struct parport *port, const char *name, | |
522 | int (*pf)(void *), void (*kf)(void *), | |
523 | void (*irq_func)(int, void *, struct pt_regs *), | |
524 | int flags, void *handle) | |
525 | { | |
526 | struct pardevice *tmp; | |
527 | ||
528 | if (port->physport->flags & PARPORT_FLAG_EXCL) { | |
529 | /* An exclusive device is registered. */ | |
530 | printk (KERN_DEBUG "%s: no more devices allowed\n", | |
531 | port->name); | |
532 | return NULL; | |
533 | } | |
534 | ||
535 | if (flags & PARPORT_DEV_LURK) { | |
536 | if (!pf || !kf) { | |
537 | printk(KERN_INFO "%s: refused to register lurking device (%s) without callbacks\n", port->name, name); | |
538 | return NULL; | |
539 | } | |
540 | } | |
541 | ||
542 | /* We up our own module reference count, and that of the port | |
543 | on which a device is to be registered, to ensure that | |
544 | neither of us gets unloaded while we sleep in (e.g.) | |
545 | kmalloc. | |
546 | */ | |
547 | if (!try_module_get(port->ops->owner)) { | |
548 | return NULL; | |
549 | } | |
550 | ||
551 | parport_get_port (port); | |
552 | ||
553 | tmp = kmalloc(sizeof(struct pardevice), GFP_KERNEL); | |
554 | if (tmp == NULL) { | |
555 | printk(KERN_WARNING "%s: memory squeeze, couldn't register %s.\n", port->name, name); | |
556 | goto out; | |
557 | } | |
558 | ||
559 | tmp->state = kmalloc(sizeof(struct parport_state), GFP_KERNEL); | |
560 | if (tmp->state == NULL) { | |
561 | printk(KERN_WARNING "%s: memory squeeze, couldn't register %s.\n", port->name, name); | |
562 | goto out_free_pardevice; | |
563 | } | |
564 | ||
565 | tmp->name = name; | |
566 | tmp->port = port; | |
567 | tmp->daisy = -1; | |
568 | tmp->preempt = pf; | |
569 | tmp->wakeup = kf; | |
570 | tmp->private = handle; | |
571 | tmp->flags = flags; | |
572 | tmp->irq_func = irq_func; | |
573 | tmp->waiting = 0; | |
574 | tmp->timeout = 5 * HZ; | |
575 | ||
576 | /* Chain this onto the list */ | |
577 | tmp->prev = NULL; | |
578 | /* | |
579 | * This function must not run from an irq handler so we don' t need | |
580 | * to clear irq on the local CPU. -arca | |
581 | */ | |
582 | spin_lock(&port->physport->pardevice_lock); | |
583 | ||
584 | if (flags & PARPORT_DEV_EXCL) { | |
585 | if (port->physport->devices) { | |
586 | spin_unlock (&port->physport->pardevice_lock); | |
587 | printk (KERN_DEBUG | |
588 | "%s: cannot grant exclusive access for " | |
589 | "device %s\n", port->name, name); | |
590 | goto out_free_all; | |
591 | } | |
592 | port->flags |= PARPORT_FLAG_EXCL; | |
593 | } | |
594 | ||
595 | tmp->next = port->physport->devices; | |
596 | wmb(); /* Make sure that tmp->next is written before it's | |
597 | added to the list; see comments marked 'no locking | |
598 | required' */ | |
599 | if (port->physport->devices) | |
600 | port->physport->devices->prev = tmp; | |
601 | port->physport->devices = tmp; | |
602 | spin_unlock(&port->physport->pardevice_lock); | |
603 | ||
604 | init_waitqueue_head(&tmp->wait_q); | |
605 | tmp->timeslice = parport_default_timeslice; | |
606 | tmp->waitnext = tmp->waitprev = NULL; | |
607 | ||
608 | /* | |
609 | * This has to be run as last thing since init_state may need other | |
610 | * pardevice fields. -arca | |
611 | */ | |
612 | port->ops->init_state(tmp, tmp->state); | |
613 | parport_device_proc_register(tmp); | |
614 | return tmp; | |
615 | ||
616 | out_free_all: | |
6044ec88 | 617 | kfree(tmp->state); |
1da177e4 | 618 | out_free_pardevice: |
6044ec88 | 619 | kfree(tmp); |
1da177e4 LT |
620 | out: |
621 | parport_put_port (port); | |
622 | module_put(port->ops->owner); | |
623 | ||
624 | return NULL; | |
625 | } | |
626 | ||
627 | /** | |
628 | * parport_unregister_device - deregister a device on a parallel port | |
629 | * @dev: pointer to structure representing device | |
630 | * | |
631 | * This undoes the effect of parport_register_device(). | |
632 | **/ | |
633 | ||
634 | void parport_unregister_device(struct pardevice *dev) | |
635 | { | |
636 | struct parport *port; | |
637 | ||
638 | #ifdef PARPORT_PARANOID | |
639 | if (dev == NULL) { | |
640 | printk(KERN_ERR "parport_unregister_device: passed NULL\n"); | |
641 | return; | |
642 | } | |
643 | #endif | |
644 | ||
645 | parport_device_proc_unregister(dev); | |
646 | ||
647 | port = dev->port->physport; | |
648 | ||
649 | if (port->cad == dev) { | |
650 | printk(KERN_DEBUG "%s: %s forgot to release port\n", | |
651 | port->name, dev->name); | |
652 | parport_release (dev); | |
653 | } | |
654 | ||
655 | spin_lock(&port->pardevice_lock); | |
656 | if (dev->next) | |
657 | dev->next->prev = dev->prev; | |
658 | if (dev->prev) | |
659 | dev->prev->next = dev->next; | |
660 | else | |
661 | port->devices = dev->next; | |
662 | ||
663 | if (dev->flags & PARPORT_DEV_EXCL) | |
664 | port->flags &= ~PARPORT_FLAG_EXCL; | |
665 | ||
666 | spin_unlock(&port->pardevice_lock); | |
667 | ||
668 | /* Make sure we haven't left any pointers around in the wait | |
669 | * list. */ | |
670 | spin_lock (&port->waitlist_lock); | |
671 | if (dev->waitprev || dev->waitnext || port->waithead == dev) { | |
672 | if (dev->waitprev) | |
673 | dev->waitprev->waitnext = dev->waitnext; | |
674 | else | |
675 | port->waithead = dev->waitnext; | |
676 | if (dev->waitnext) | |
677 | dev->waitnext->waitprev = dev->waitprev; | |
678 | else | |
679 | port->waittail = dev->waitprev; | |
680 | } | |
681 | spin_unlock (&port->waitlist_lock); | |
682 | ||
683 | kfree(dev->state); | |
684 | kfree(dev); | |
685 | ||
686 | module_put(port->ops->owner); | |
687 | parport_put_port (port); | |
688 | } | |
689 | ||
690 | /** | |
691 | * parport_find_number - find a parallel port by number | |
692 | * @number: parallel port number | |
693 | * | |
694 | * This returns the parallel port with the specified number, or | |
695 | * %NULL if there is none. | |
696 | * | |
697 | * There is an implicit parport_get_port() done already; to throw | |
698 | * away the reference to the port that parport_find_number() | |
699 | * gives you, use parport_put_port(). | |
700 | */ | |
701 | ||
702 | struct parport *parport_find_number (int number) | |
703 | { | |
704 | struct parport *port, *result = NULL; | |
705 | ||
706 | if (list_empty(&portlist)) | |
707 | get_lowlevel_driver (); | |
708 | ||
709 | spin_lock (&parportlist_lock); | |
710 | list_for_each_entry(port, &portlist, list) { | |
711 | if (port->number == number) { | |
712 | result = parport_get_port (port); | |
713 | break; | |
714 | } | |
715 | } | |
716 | spin_unlock (&parportlist_lock); | |
717 | return result; | |
718 | } | |
719 | ||
720 | /** | |
721 | * parport_find_base - find a parallel port by base address | |
722 | * @base: base I/O address | |
723 | * | |
724 | * This returns the parallel port with the specified base | |
725 | * address, or %NULL if there is none. | |
726 | * | |
727 | * There is an implicit parport_get_port() done already; to throw | |
728 | * away the reference to the port that parport_find_base() | |
729 | * gives you, use parport_put_port(). | |
730 | */ | |
731 | ||
732 | struct parport *parport_find_base (unsigned long base) | |
733 | { | |
734 | struct parport *port, *result = NULL; | |
735 | ||
736 | if (list_empty(&portlist)) | |
737 | get_lowlevel_driver (); | |
738 | ||
739 | spin_lock (&parportlist_lock); | |
740 | list_for_each_entry(port, &portlist, list) { | |
741 | if (port->base == base) { | |
742 | result = parport_get_port (port); | |
743 | break; | |
744 | } | |
745 | } | |
746 | spin_unlock (&parportlist_lock); | |
747 | return result; | |
748 | } | |
749 | ||
750 | /** | |
751 | * parport_claim - claim access to a parallel port device | |
752 | * @dev: pointer to structure representing a device on the port | |
753 | * | |
754 | * This function will not block and so can be used from interrupt | |
755 | * context. If parport_claim() succeeds in claiming access to | |
756 | * the port it returns zero and the port is available to use. It | |
757 | * may fail (returning non-zero) if the port is in use by another | |
758 | * driver and that driver is not willing to relinquish control of | |
759 | * the port. | |
760 | **/ | |
761 | ||
762 | int parport_claim(struct pardevice *dev) | |
763 | { | |
764 | struct pardevice *oldcad; | |
765 | struct parport *port = dev->port->physport; | |
766 | unsigned long flags; | |
767 | ||
768 | if (port->cad == dev) { | |
769 | printk(KERN_INFO "%s: %s already owner\n", | |
770 | dev->port->name,dev->name); | |
771 | return 0; | |
772 | } | |
773 | ||
774 | /* Preempt any current device */ | |
775 | write_lock_irqsave (&port->cad_lock, flags); | |
776 | if ((oldcad = port->cad) != NULL) { | |
777 | if (oldcad->preempt) { | |
778 | if (oldcad->preempt(oldcad->private)) | |
779 | goto blocked; | |
780 | port->ops->save_state(port, dev->state); | |
781 | } else | |
782 | goto blocked; | |
783 | ||
784 | if (port->cad != oldcad) { | |
785 | /* I think we'll actually deadlock rather than | |
786 | get here, but just in case.. */ | |
787 | printk(KERN_WARNING | |
788 | "%s: %s released port when preempted!\n", | |
789 | port->name, oldcad->name); | |
790 | if (port->cad) | |
791 | goto blocked; | |
792 | } | |
793 | } | |
794 | ||
795 | /* Can't fail from now on, so mark ourselves as no longer waiting. */ | |
796 | if (dev->waiting & 1) { | |
797 | dev->waiting = 0; | |
798 | ||
799 | /* Take ourselves out of the wait list again. */ | |
800 | spin_lock_irq (&port->waitlist_lock); | |
801 | if (dev->waitprev) | |
802 | dev->waitprev->waitnext = dev->waitnext; | |
803 | else | |
804 | port->waithead = dev->waitnext; | |
805 | if (dev->waitnext) | |
806 | dev->waitnext->waitprev = dev->waitprev; | |
807 | else | |
808 | port->waittail = dev->waitprev; | |
809 | spin_unlock_irq (&port->waitlist_lock); | |
810 | dev->waitprev = dev->waitnext = NULL; | |
811 | } | |
812 | ||
813 | /* Now we do the change of devices */ | |
814 | port->cad = dev; | |
815 | ||
816 | #ifdef CONFIG_PARPORT_1284 | |
817 | /* If it's a mux port, select it. */ | |
818 | if (dev->port->muxport >= 0) { | |
819 | /* FIXME */ | |
820 | port->muxsel = dev->port->muxport; | |
821 | } | |
822 | ||
823 | /* If it's a daisy chain device, select it. */ | |
824 | if (dev->daisy >= 0) { | |
825 | /* This could be lazier. */ | |
826 | if (!parport_daisy_select (port, dev->daisy, | |
827 | IEEE1284_MODE_COMPAT)) | |
828 | port->daisy = dev->daisy; | |
829 | } | |
830 | #endif /* IEEE1284.3 support */ | |
831 | ||
832 | /* Restore control registers */ | |
833 | port->ops->restore_state(port, dev->state); | |
834 | write_unlock_irqrestore(&port->cad_lock, flags); | |
835 | dev->time = jiffies; | |
836 | return 0; | |
837 | ||
838 | blocked: | |
839 | /* If this is the first time we tried to claim the port, register an | |
840 | interest. This is only allowed for devices sleeping in | |
841 | parport_claim_or_block(), or those with a wakeup function. */ | |
842 | ||
843 | /* The cad_lock is still held for writing here */ | |
844 | if (dev->waiting & 2 || dev->wakeup) { | |
845 | spin_lock (&port->waitlist_lock); | |
846 | if (test_and_set_bit(0, &dev->waiting) == 0) { | |
847 | /* First add ourselves to the end of the wait list. */ | |
848 | dev->waitnext = NULL; | |
849 | dev->waitprev = port->waittail; | |
850 | if (port->waittail) { | |
851 | port->waittail->waitnext = dev; | |
852 | port->waittail = dev; | |
853 | } else | |
854 | port->waithead = port->waittail = dev; | |
855 | } | |
856 | spin_unlock (&port->waitlist_lock); | |
857 | } | |
858 | write_unlock_irqrestore (&port->cad_lock, flags); | |
859 | return -EAGAIN; | |
860 | } | |
861 | ||
862 | /** | |
863 | * parport_claim_or_block - claim access to a parallel port device | |
864 | * @dev: pointer to structure representing a device on the port | |
865 | * | |
866 | * This behaves like parport_claim(), but will block if necessary | |
867 | * to wait for the port to be free. A return value of 1 | |
868 | * indicates that it slept; 0 means that it succeeded without | |
869 | * needing to sleep. A negative error code indicates failure. | |
870 | **/ | |
871 | ||
872 | int parport_claim_or_block(struct pardevice *dev) | |
873 | { | |
874 | int r; | |
875 | ||
876 | /* Signal to parport_claim() that we can wait even without a | |
877 | wakeup function. */ | |
878 | dev->waiting = 2; | |
879 | ||
880 | /* Try to claim the port. If this fails, we need to sleep. */ | |
881 | r = parport_claim(dev); | |
882 | if (r == -EAGAIN) { | |
883 | #ifdef PARPORT_DEBUG_SHARING | |
884 | printk(KERN_DEBUG "%s: parport_claim() returned -EAGAIN\n", dev->name); | |
885 | #endif | |
886 | /* | |
887 | * FIXME!!! Use the proper locking for dev->waiting, | |
888 | * and make this use the "wait_event_interruptible()" | |
889 | * interfaces. The cli/sti that used to be here | |
890 | * did nothing. | |
891 | * | |
892 | * See also parport_release() | |
893 | */ | |
894 | ||
895 | /* If dev->waiting is clear now, an interrupt | |
896 | gave us the port and we would deadlock if we slept. */ | |
897 | if (dev->waiting) { | |
898 | interruptible_sleep_on (&dev->wait_q); | |
899 | if (signal_pending (current)) { | |
900 | return -EINTR; | |
901 | } | |
902 | r = 1; | |
903 | } else { | |
904 | r = 0; | |
905 | #ifdef PARPORT_DEBUG_SHARING | |
906 | printk(KERN_DEBUG "%s: didn't sleep in parport_claim_or_block()\n", | |
907 | dev->name); | |
908 | #endif | |
909 | } | |
910 | ||
911 | #ifdef PARPORT_DEBUG_SHARING | |
912 | if (dev->port->physport->cad != dev) | |
913 | printk(KERN_DEBUG "%s: exiting parport_claim_or_block " | |
914 | "but %s owns port!\n", dev->name, | |
915 | dev->port->physport->cad ? | |
916 | dev->port->physport->cad->name:"nobody"); | |
917 | #endif | |
918 | } | |
919 | dev->waiting = 0; | |
920 | return r; | |
921 | } | |
922 | ||
923 | /** | |
924 | * parport_release - give up access to a parallel port device | |
925 | * @dev: pointer to structure representing parallel port device | |
926 | * | |
927 | * This function cannot fail, but it should not be called without | |
928 | * the port claimed. Similarly, if the port is already claimed | |
929 | * you should not try claiming it again. | |
930 | **/ | |
931 | ||
932 | void parport_release(struct pardevice *dev) | |
933 | { | |
934 | struct parport *port = dev->port->physport; | |
935 | struct pardevice *pd; | |
936 | unsigned long flags; | |
937 | ||
938 | /* Make sure that dev is the current device */ | |
939 | write_lock_irqsave(&port->cad_lock, flags); | |
940 | if (port->cad != dev) { | |
941 | write_unlock_irqrestore (&port->cad_lock, flags); | |
942 | printk(KERN_WARNING "%s: %s tried to release parport " | |
943 | "when not owner\n", port->name, dev->name); | |
944 | return; | |
945 | } | |
946 | ||
947 | #ifdef CONFIG_PARPORT_1284 | |
948 | /* If this is on a mux port, deselect it. */ | |
949 | if (dev->port->muxport >= 0) { | |
950 | /* FIXME */ | |
951 | port->muxsel = -1; | |
952 | } | |
953 | ||
954 | /* If this is a daisy device, deselect it. */ | |
955 | if (dev->daisy >= 0) { | |
956 | parport_daisy_deselect_all (port); | |
957 | port->daisy = -1; | |
958 | } | |
959 | #endif | |
960 | ||
961 | port->cad = NULL; | |
962 | write_unlock_irqrestore(&port->cad_lock, flags); | |
963 | ||
964 | /* Save control registers */ | |
965 | port->ops->save_state(port, dev->state); | |
966 | ||
967 | /* If anybody is waiting, find out who's been there longest and | |
968 | then wake them up. (Note: no locking required) */ | |
969 | /* !!! LOCKING IS NEEDED HERE */ | |
970 | for (pd = port->waithead; pd; pd = pd->waitnext) { | |
971 | if (pd->waiting & 2) { /* sleeping in claim_or_block */ | |
972 | parport_claim(pd); | |
973 | if (waitqueue_active(&pd->wait_q)) | |
974 | wake_up_interruptible(&pd->wait_q); | |
975 | return; | |
976 | } else if (pd->wakeup) { | |
977 | pd->wakeup(pd->private); | |
978 | if (dev->port->cad) /* racy but no matter */ | |
979 | return; | |
980 | } else { | |
981 | printk(KERN_ERR "%s: don't know how to wake %s\n", port->name, pd->name); | |
982 | } | |
983 | } | |
984 | ||
985 | /* Nobody was waiting, so walk the list to see if anyone is | |
986 | interested in being woken up. (Note: no locking required) */ | |
987 | /* !!! LOCKING IS NEEDED HERE */ | |
988 | for (pd = port->devices; (port->cad == NULL) && pd; pd = pd->next) { | |
989 | if (pd->wakeup && pd != dev) | |
990 | pd->wakeup(pd->private); | |
991 | } | |
992 | } | |
993 | ||
994 | /* Exported symbols for modules. */ | |
995 | ||
996 | EXPORT_SYMBOL(parport_claim); | |
997 | EXPORT_SYMBOL(parport_claim_or_block); | |
998 | EXPORT_SYMBOL(parport_release); | |
999 | EXPORT_SYMBOL(parport_register_port); | |
1000 | EXPORT_SYMBOL(parport_announce_port); | |
1001 | EXPORT_SYMBOL(parport_remove_port); | |
1002 | EXPORT_SYMBOL(parport_register_driver); | |
1003 | EXPORT_SYMBOL(parport_unregister_driver); | |
1004 | EXPORT_SYMBOL(parport_register_device); | |
1005 | EXPORT_SYMBOL(parport_unregister_device); | |
94b82095 | 1006 | EXPORT_SYMBOL(parport_get_port); |
1da177e4 LT |
1007 | EXPORT_SYMBOL(parport_put_port); |
1008 | EXPORT_SYMBOL(parport_find_number); | |
1009 | EXPORT_SYMBOL(parport_find_base); | |
1010 | ||
1011 | MODULE_LICENSE("GPL"); |