xref: /dragonfly/sys/kern/kern_device.c (revision 768af85b) 
1 /*
2  * Copyright (c) 2003 Matthew Dillon <dillon@backplane.com> All rights reserved.
3  * cdevsw from kern/kern_conf.c Copyright (c) 1995 Terrence R. Lambert
4  * cdevsw from kern/kern_conf.c Copyright (c) 1995 Julian R. Elishcer,
5  *							All rights reserved.
6  * Copyright (c) 1982, 1986, 1991, 1993
7  *	The Regents of the University of California.  All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  *
30  * $DragonFly: src/sys/kern/kern_device.c,v 1.27 2007/07/23 18:59:50 dillon Exp $
31  */
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/kernel.h>
35 #include <sys/sysctl.h>
36 #include <sys/systm.h>
37 #include <sys/module.h>
38 #include <sys/malloc.h>
39 #include <sys/conf.h>
40 #include <sys/bio.h>
41 #include <sys/buf.h>
42 #include <sys/vnode.h>
43 #include <sys/queue.h>
44 #include <sys/device.h>
45 #include <sys/tree.h>
46 #include <sys/syslink_rpc.h>
47 #include <sys/proc.h>
48 #include <machine/stdarg.h>
49 #include <sys/thread2.h>
50 #include <sys/devfs.h>
51 
52 /*
53  * system link descriptors identify the command in the
54  * arguments structure.
55  */
56 #define DDESCNAME(name) __CONCAT(__CONCAT(dev_,name),_desc)
57 
58 #define DEVOP_DESC_INIT(name)						\
59 	    struct syslink_desc DDESCNAME(name) = {			\
60 		__offsetof(struct dev_ops, __CONCAT(d_, name)),	\
61 	    #name }
62 
63 DEVOP_DESC_INIT(default);
64 DEVOP_DESC_INIT(open);
65 DEVOP_DESC_INIT(close);
66 DEVOP_DESC_INIT(read);
67 DEVOP_DESC_INIT(write);
68 DEVOP_DESC_INIT(ioctl);
69 DEVOP_DESC_INIT(dump);
70 DEVOP_DESC_INIT(psize);
71 DEVOP_DESC_INIT(poll);
72 DEVOP_DESC_INIT(mmap);
73 DEVOP_DESC_INIT(strategy);
74 DEVOP_DESC_INIT(kqfilter);
75 DEVOP_DESC_INIT(revoke);
76 DEVOP_DESC_INIT(clone);
77 
78 /*
79  * Misc default ops
80  */
81 struct dev_ops dead_dev_ops;
82 
83 struct dev_ops default_dev_ops = {
84 	{ "null" },
85 	.d_default = NULL,	/* must be NULL */
86 	.d_open = noopen,
87 	.d_close = noclose,
88 	.d_read = noread,
89 	.d_write = nowrite,
90 	.d_ioctl = noioctl,
91 	.d_poll = nopoll,
92 	.d_mmap = nommap,
93 	.d_strategy = nostrategy,
94 	.d_dump = nodump,
95 	.d_psize = nopsize,
96 	.d_kqfilter = nokqfilter,
97 	.d_revoke = norevoke,
98 	.d_clone = noclone
99 };
100 
101 /************************************************************************
102  *			GENERAL DEVICE API FUNCTIONS			*
103  ************************************************************************/
104 
105 int
106 dev_dopen(cdev_t dev, int oflags, int devtype, struct ucred *cred)
107 {
108 	struct dev_open_args ap;
109 
110 	ap.a_head.a_desc = &dev_open_desc;
111 	ap.a_head.a_dev = dev;
112 	ap.a_oflags = oflags;
113 	ap.a_devtype = devtype;
114 	ap.a_cred = cred;
115 	return(dev->si_ops->d_open(&ap));
116 }
117 
118 int
119 dev_dclose(cdev_t dev, int fflag, int devtype)
120 {
121 	struct dev_close_args ap;
122 
123 	ap.a_head.a_desc = &dev_close_desc;
124 	ap.a_head.a_dev = dev;
125 	ap.a_fflag = fflag;
126 	ap.a_devtype = devtype;
127 	return(dev->si_ops->d_close(&ap));
128 }
129 
130 int
131 dev_dread(cdev_t dev, struct uio *uio, int ioflag)
132 {
133 	struct dev_read_args ap;
134 	int error;
135 
136 	ap.a_head.a_desc = &dev_read_desc;
137 	ap.a_head.a_dev = dev;
138 	ap.a_uio = uio;
139 	ap.a_ioflag = ioflag;
140 	error = dev->si_ops->d_read(&ap);
141 	if (error == 0)
142 		dev->si_lastread = time_second;
143 	return (error);
144 }
145 
146 int
147 dev_dwrite(cdev_t dev, struct uio *uio, int ioflag)
148 {
149 	struct dev_write_args ap;
150 	int error;
151 
152 	dev->si_lastwrite = time_second;
153 	ap.a_head.a_desc = &dev_write_desc;
154 	ap.a_head.a_dev = dev;
155 	ap.a_uio = uio;
156 	ap.a_ioflag = ioflag;
157 	error = dev->si_ops->d_write(&ap);
158 	return (error);
159 }
160 
161 int
162 dev_dioctl(cdev_t dev, u_long cmd, caddr_t data, int fflag, struct ucred *cred,
163 	   struct sysmsg *msg)
164 {
165 	struct dev_ioctl_args ap;
166 
167 	ap.a_head.a_desc = &dev_ioctl_desc;
168 	ap.a_head.a_dev = dev;
169 	ap.a_cmd = cmd;
170 	ap.a_data = data;
171 	ap.a_fflag = fflag;
172 	ap.a_cred = cred;
173 	ap.a_sysmsg = msg;
174 	return(dev->si_ops->d_ioctl(&ap));
175 }
176 
177 int
178 dev_dpoll(cdev_t dev, int events)
179 {
180 	struct dev_poll_args ap;
181 	int error;
182 
183 	ap.a_head.a_desc = &dev_poll_desc;
184 	ap.a_head.a_dev = dev;
185 	ap.a_events = events;
186 	error = dev->si_ops->d_poll(&ap);
187 	if (error == 0)
188 		return(ap.a_events);
189 	return (seltrue(dev, events));
190 }
191 
192 int
193 dev_dmmap(cdev_t dev, vm_offset_t offset, int nprot)
194 {
195 	struct dev_mmap_args ap;
196 	int error;
197 
198 	ap.a_head.a_desc = &dev_mmap_desc;
199 	ap.a_head.a_dev = dev;
200 	ap.a_offset = offset;
201 	ap.a_nprot = nprot;
202 	error = dev->si_ops->d_mmap(&ap);
203 	if (error == 0)
204 		return(ap.a_result);
205 	return(-1);
206 }
207 
208 int
209 dev_dclone(cdev_t dev)
210 {
211 	struct dev_clone_args ap;
212 
213 	ap.a_head.a_desc = &dev_clone_desc;
214 	ap.a_head.a_dev = dev;
215 	return (dev->si_ops->d_clone(&ap));
216 }
217 
218 int
219 dev_drevoke(cdev_t dev)
220 {
221 	struct dev_revoke_args ap;
222 
223 	ap.a_head.a_desc = &dev_revoke_desc;
224 	ap.a_head.a_dev = dev;
225 	return (dev->si_ops->d_revoke(&ap));
226 }
227 
228 /*
229  * Core device strategy call, used to issue I/O on a device.  There are
230  * two versions, a non-chained version and a chained version.  The chained
231  * version reuses a BIO set up by vn_strategy().  The only difference is
232  * that, for now, we do not push a new tracking structure when chaining
233  * from vn_strategy.  XXX this will ultimately have to change.
234  */
235 void
236 dev_dstrategy(cdev_t dev, struct bio *bio)
237 {
238 	struct dev_strategy_args ap;
239 	struct bio_track *track;
240 
241 	ap.a_head.a_desc = &dev_strategy_desc;
242 	ap.a_head.a_dev = dev;
243 	ap.a_bio = bio;
244 
245 	KKASSERT(bio->bio_track == NULL);
246 	KKASSERT(bio->bio_buf->b_cmd != BUF_CMD_DONE);
247 	if (bio->bio_buf->b_cmd == BUF_CMD_READ)
248 	    track = &dev->si_track_read;
249 	else
250 	    track = &dev->si_track_write;
251 	bio_track_ref(track);
252 	bio->bio_track = track;
253 	KKASSERT((bio->bio_flags & BIO_DONE) == 0);
254 	(void)dev->si_ops->d_strategy(&ap);
255 }
256 
257 void
258 dev_dstrategy_chain(cdev_t dev, struct bio *bio)
259 {
260 	struct dev_strategy_args ap;
261 
262 	ap.a_head.a_desc = &dev_strategy_desc;
263 	ap.a_head.a_dev = dev;
264 	ap.a_bio = bio;
265 
266 	KKASSERT(bio->bio_track != NULL);
267 	KKASSERT((bio->bio_flags & BIO_DONE) == 0);
268 	(void)dev->si_ops->d_strategy(&ap);
269 }
270 
271 /*
272  * note: the disk layer is expected to set count, blkno, and secsize before
273  * forwarding the message.
274  */
275 int
276 dev_ddump(cdev_t dev, void *virtual, vm_offset_t physical, off_t offset,
277     size_t length)
278 {
279 	struct dev_dump_args ap;
280 
281 	ap.a_head.a_desc = &dev_dump_desc;
282 	ap.a_head.a_dev = dev;
283 	ap.a_count = 0;
284 	ap.a_blkno = 0;
285 	ap.a_secsize = 0;
286 	ap.a_virtual = virtual;
287 	ap.a_physical = physical;
288 	ap.a_offset = offset;
289 	ap.a_length = length;
290 	return(dev->si_ops->d_dump(&ap));
291 }
292 
293 int64_t
294 dev_dpsize(cdev_t dev)
295 {
296 	struct dev_psize_args ap;
297 	int error;
298 
299 	ap.a_head.a_desc = &dev_psize_desc;
300 	ap.a_head.a_dev = dev;
301 	error = dev->si_ops->d_psize(&ap);
302 	if (error == 0)
303 		return (ap.a_result);
304 	return(-1);
305 }
306 
307 int
308 dev_dkqfilter(cdev_t dev, struct knote *kn)
309 {
310 	struct dev_kqfilter_args ap;
311 	int error;
312 
313 	ap.a_head.a_desc = &dev_kqfilter_desc;
314 	ap.a_head.a_dev = dev;
315 	ap.a_kn = kn;
316 	error = dev->si_ops->d_kqfilter(&ap);
317 	if (error == 0)
318 		return(ap.a_result);
319 	return(ENODEV);
320 }
321 
322 /************************************************************************
323  *			DEVICE HELPER FUNCTIONS				*
324  ************************************************************************/
325 
326 /*
327  * MPSAFE
328  */
329 int
330 dev_drefs(cdev_t dev)
331 {
332     return(dev->si_sysref.refcnt);
333 }
334 
335 /*
336  * MPSAFE
337  */
338 const char *
339 dev_dname(cdev_t dev)
340 {
341     return(dev->si_ops->head.name);
342 }
343 
344 /*
345  * MPSAFE
346  */
347 int
348 dev_dflags(cdev_t dev)
349 {
350     return(dev->si_ops->head.flags);
351 }
352 
353 /*
354  * MPSAFE
355  */
356 int
357 dev_dmaj(cdev_t dev)
358 {
359     return(dev->si_ops->head.maj);
360 }
361 
362 /*
363  * Used when forwarding a request through layers.  The caller adjusts
364  * ap->a_head.a_dev and then calls this function.
365  */
366 int
367 dev_doperate(struct dev_generic_args *ap)
368 {
369     int (*func)(struct dev_generic_args *);
370 
371     func = *(void **)((char *)ap->a_dev->si_ops + ap->a_desc->sd_offset);
372     return (func(ap));
373 }
374 
375 /*
376  * Used by the console intercept code only.  Issue an operation through
377  * a foreign ops structure allowing the ops structure associated
378  * with the device to remain intact.
379  */
380 int
381 dev_doperate_ops(struct dev_ops *ops, struct dev_generic_args *ap)
382 {
383     int (*func)(struct dev_generic_args *);
384 
385     func = *(void **)((char *)ops + ap->a_desc->sd_offset);
386     return (func(ap));
387 }
388 
389 /*
390  * Convert a template dev_ops into the real thing by filling in
391  * uninitialized fields.
392  */
393 void
394 compile_dev_ops(struct dev_ops *ops)
395 {
396 	int offset;
397 
398 	for (offset = offsetof(struct dev_ops, dev_ops_first_field);
399 	     offset <= offsetof(struct dev_ops, dev_ops_last_field);
400 	     offset += sizeof(void *)
401 	) {
402 		void **func_p = (void **)((char *)ops + offset);
403 		void **def_p = (void **)((char *)&default_dev_ops + offset);
404 		if (*func_p == NULL) {
405 			if (ops->d_default)
406 				*func_p = ops->d_default;
407 			else
408 				*func_p = *def_p;
409 		}
410 	}
411 }
412 
413 /************************************************************************
414  *			MAJOR/MINOR SPACE FUNCTION 			*
415  ************************************************************************/
416 
417 /*
418  * This makes a dev_ops entry visible to userland (e.g /dev/<blah>).
419  *
420  * Disk devices typically register their major, e.g. 'ad0', and then call
421  * into the disk label management code which overloads its own onto e.g. 'ad0'
422  * to support all the various slice and partition combinations.
423  *
424  * The mask/match supplied in this call are a full 32 bits and the same
425  * mask and match must be specified in a later dev_ops_remove() call to
426  * match this add.  However, the match value for the minor number should never
427  * have any bits set in the major number's bit range (8-15).  The mask value
428  * may be conveniently specified as -1 without creating any major number
429  * interference.
430  */
431 
432 static
433 int
434 rb_dev_ops_compare(struct dev_ops_maj *a, struct dev_ops_maj *b)
435 {
436     if (a->maj < b->maj)
437 	return(-1);
438     else if (a->maj > b->maj)
439 	return(1);
440     return(0);
441 }
442 
443 RB_GENERATE2(dev_ops_rb_tree, dev_ops_maj, rbnode, rb_dev_ops_compare, int, maj);
444 
445 struct dev_ops_rb_tree dev_ops_rbhead = RB_INITIALIZER(dev_ops_rbhead);
446 
447 int
448 dev_ops_remove_all(struct dev_ops *ops)
449 {
450 	return devfs_destroy_dev_by_ops(ops, -1);
451 }
452 
453 int
454 dev_ops_remove_minor(struct dev_ops *ops, int minor)
455 {
456 	return devfs_destroy_dev_by_ops(ops, minor);
457 }
458 
459 struct dev_ops *
460 dev_ops_intercept(cdev_t dev, struct dev_ops *iops)
461 {
462 	struct dev_ops *oops = dev->si_ops;
463 
464 	compile_dev_ops(iops);
465 	iops->head.maj = oops->head.maj;
466 	iops->head.data = oops->head.data;
467 	iops->head.flags = oops->head.flags;
468 	dev->si_ops = iops;
469 	dev->si_flags |= SI_INTERCEPTED;
470 
471 	return (oops);
472 }
473 
474 void
475 dev_ops_restore(cdev_t dev, struct dev_ops *oops)
476 {
477 	struct dev_ops *iops = dev->si_ops;
478 
479 	dev->si_ops = oops;
480 	dev->si_flags &= ~SI_INTERCEPTED;
481 	iops->head.maj = 0;
482 	iops->head.data = NULL;
483 	iops->head.flags = 0;
484 }
485 
486 /************************************************************************
487  *			DEFAULT DEV OPS FUNCTIONS			*
488  ************************************************************************/
489 
490 
491 /*
492  * Unsupported devswitch functions (e.g. for writing to read-only device).
493  * XXX may belong elsewhere.
494  */
495 int
496 norevoke(struct dev_revoke_args *ap)
497 {
498 	/* take no action */
499 	return(0);
500 }
501 
502 int
503 noclone(struct dev_clone_args *ap)
504 {
505 	/* take no action */
506 	return (0);	/* allow the clone */
507 }
508 
509 int
510 noopen(struct dev_open_args *ap)
511 {
512 	return (ENODEV);
513 }
514 
515 int
516 noclose(struct dev_close_args *ap)
517 {
518 	return (ENODEV);
519 }
520 
521 int
522 noread(struct dev_read_args *ap)
523 {
524 	return (ENODEV);
525 }
526 
527 int
528 nowrite(struct dev_write_args *ap)
529 {
530 	return (ENODEV);
531 }
532 
533 int
534 noioctl(struct dev_ioctl_args *ap)
535 {
536 	return (ENODEV);
537 }
538 
539 int
540 nokqfilter(struct dev_kqfilter_args *ap)
541 {
542 	return (ENODEV);
543 }
544 
545 int
546 nommap(struct dev_mmap_args *ap)
547 {
548 	return (ENODEV);
549 }
550 
551 int
552 nopoll(struct dev_poll_args *ap)
553 {
554 	ap->a_events = 0;
555 	return(0);
556 }
557 
558 int
559 nostrategy(struct dev_strategy_args *ap)
560 {
561 	struct bio *bio = ap->a_bio;
562 
563 	bio->bio_buf->b_flags |= B_ERROR;
564 	bio->bio_buf->b_error = EOPNOTSUPP;
565 	biodone(bio);
566 	return(0);
567 }
568 
569 int
570 nopsize(struct dev_psize_args *ap)
571 {
572 	ap->a_result = 0;
573 	return(0);
574 }
575 
576 int
577 nodump(struct dev_dump_args *ap)
578 {
579 	return (ENODEV);
580 }
581 
582 /*
583  * XXX this is probably bogus.  Any device that uses it isn't checking the
584  * minor number.
585  */
586 int
587 nullopen(struct dev_open_args *ap)
588 {
589 	return (0);
590 }
591 
592 int
593 nullclose(struct dev_close_args *ap)
594 {
595 	return (0);
596 }
597 
598