xref: /dragonfly/sys/kern/kern_device.c (revision 1b722dce) 
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)
277 {
278 	struct dev_dump_args ap;
279 
280 	ap.a_head.a_desc = &dev_dump_desc;
281 	ap.a_head.a_dev = dev;
282 	ap.a_count = 0;
283 	ap.a_blkno = 0;
284 	ap.a_secsize = 0;
285 	return(dev->si_ops->d_dump(&ap));
286 }
287 
288 int64_t
289 dev_dpsize(cdev_t dev)
290 {
291 	struct dev_psize_args ap;
292 	int error;
293 
294 	ap.a_head.a_desc = &dev_psize_desc;
295 	ap.a_head.a_dev = dev;
296 	error = dev->si_ops->d_psize(&ap);
297 	if (error == 0)
298 		return (ap.a_result);
299 	return(-1);
300 }
301 
302 int
303 dev_dkqfilter(cdev_t dev, struct knote *kn)
304 {
305 	struct dev_kqfilter_args ap;
306 	int error;
307 
308 	ap.a_head.a_desc = &dev_kqfilter_desc;
309 	ap.a_head.a_dev = dev;
310 	ap.a_kn = kn;
311 	error = dev->si_ops->d_kqfilter(&ap);
312 	if (error == 0)
313 		return(ap.a_result);
314 	return(ENODEV);
315 }
316 
317 /************************************************************************
318  *			DEVICE HELPER FUNCTIONS				*
319  ************************************************************************/
320 
321 /*
322  * MPSAFE
323  */
324 int
325 dev_drefs(cdev_t dev)
326 {
327     return(dev->si_sysref.refcnt);
328 }
329 
330 /*
331  * MPSAFE
332  */
333 const char *
334 dev_dname(cdev_t dev)
335 {
336     return(dev->si_ops->head.name);
337 }
338 
339 /*
340  * MPSAFE
341  */
342 int
343 dev_dflags(cdev_t dev)
344 {
345     return(dev->si_ops->head.flags);
346 }
347 
348 /*
349  * MPSAFE
350  */
351 int
352 dev_dmaj(cdev_t dev)
353 {
354     return(dev->si_ops->head.maj);
355 }
356 
357 /*
358  * Used when forwarding a request through layers.  The caller adjusts
359  * ap->a_head.a_dev and then calls this function.
360  */
361 int
362 dev_doperate(struct dev_generic_args *ap)
363 {
364     int (*func)(struct dev_generic_args *);
365 
366     func = *(void **)((char *)ap->a_dev->si_ops + ap->a_desc->sd_offset);
367     return (func(ap));
368 }
369 
370 /*
371  * Used by the console intercept code only.  Issue an operation through
372  * a foreign ops structure allowing the ops structure associated
373  * with the device to remain intact.
374  */
375 int
376 dev_doperate_ops(struct dev_ops *ops, struct dev_generic_args *ap)
377 {
378     int (*func)(struct dev_generic_args *);
379 
380     func = *(void **)((char *)ops + ap->a_desc->sd_offset);
381     return (func(ap));
382 }
383 
384 /*
385  * Convert a template dev_ops into the real thing by filling in
386  * uninitialized fields.
387  */
388 void
389 compile_dev_ops(struct dev_ops *ops)
390 {
391 	int offset;
392 
393 	for (offset = offsetof(struct dev_ops, dev_ops_first_field);
394 	     offset <= offsetof(struct dev_ops, dev_ops_last_field);
395 	     offset += sizeof(void *)
396 	) {
397 		void **func_p = (void **)((char *)ops + offset);
398 		void **def_p = (void **)((char *)&default_dev_ops + offset);
399 		if (*func_p == NULL) {
400 			if (ops->d_default)
401 				*func_p = ops->d_default;
402 			else
403 				*func_p = *def_p;
404 		}
405 	}
406 }
407 
408 /************************************************************************
409  *			MAJOR/MINOR SPACE FUNCTION 			*
410  ************************************************************************/
411 
412 /*
413  * This makes a dev_ops entry visible to userland (e.g /dev/<blah>).
414  *
415  * Disk devices typically register their major, e.g. 'ad0', and then call
416  * into the disk label management code which overloads its own onto e.g. 'ad0'
417  * to support all the various slice and partition combinations.
418  *
419  * The mask/match supplied in this call are a full 32 bits and the same
420  * mask and match must be specified in a later dev_ops_remove() call to
421  * match this add.  However, the match value for the minor number should never
422  * have any bits set in the major number's bit range (8-15).  The mask value
423  * may be conveniently specified as -1 without creating any major number
424  * interference.
425  */
426 
427 static
428 int
429 rb_dev_ops_compare(struct dev_ops_maj *a, struct dev_ops_maj *b)
430 {
431     if (a->maj < b->maj)
432 	return(-1);
433     else if (a->maj > b->maj)
434 	return(1);
435     return(0);
436 }
437 
438 RB_GENERATE2(dev_ops_rb_tree, dev_ops_maj, rbnode, rb_dev_ops_compare, int, maj);
439 
440 struct dev_ops_rb_tree dev_ops_rbhead = RB_INITIALIZER(dev_ops_rbhead);
441 
442 int
443 dev_ops_remove_all(struct dev_ops *ops)
444 {
445 	return devfs_destroy_dev_by_ops(ops, -1);
446 }
447 
448 int
449 dev_ops_remove_minor(struct dev_ops *ops, int minor)
450 {
451 	return devfs_destroy_dev_by_ops(ops, minor);
452 }
453 
454 struct dev_ops *
455 dev_ops_intercept(cdev_t dev, struct dev_ops *iops)
456 {
457 	struct dev_ops *oops = dev->si_ops;
458 
459 	compile_dev_ops(iops);
460 	iops->head.maj = oops->head.maj;
461 	iops->head.data = oops->head.data;
462 	iops->head.flags = oops->head.flags;
463 	dev->si_ops = iops;
464 	dev->si_flags |= SI_INTERCEPTED;
465 
466 	return (oops);
467 }
468 
469 void
470 dev_ops_restore(cdev_t dev, struct dev_ops *oops)
471 {
472 	struct dev_ops *iops = dev->si_ops;
473 
474 	dev->si_ops = oops;
475 	dev->si_flags &= ~SI_INTERCEPTED;
476 	iops->head.maj = 0;
477 	iops->head.data = NULL;
478 	iops->head.flags = 0;
479 }
480 
481 /************************************************************************
482  *			DEFAULT DEV OPS FUNCTIONS			*
483  ************************************************************************/
484 
485 
486 /*
487  * Unsupported devswitch functions (e.g. for writing to read-only device).
488  * XXX may belong elsewhere.
489  */
490 int
491 norevoke(struct dev_revoke_args *ap)
492 {
493 	/* take no action */
494 	return(0);
495 }
496 
497 int
498 noclone(struct dev_clone_args *ap)
499 {
500 	/* take no action */
501 	return (0);	/* allow the clone */
502 }
503 
504 int
505 noopen(struct dev_open_args *ap)
506 {
507 	return (ENODEV);
508 }
509 
510 int
511 noclose(struct dev_close_args *ap)
512 {
513 	return (ENODEV);
514 }
515 
516 int
517 noread(struct dev_read_args *ap)
518 {
519 	return (ENODEV);
520 }
521 
522 int
523 nowrite(struct dev_write_args *ap)
524 {
525 	return (ENODEV);
526 }
527 
528 int
529 noioctl(struct dev_ioctl_args *ap)
530 {
531 	return (ENODEV);
532 }
533 
534 int
535 nokqfilter(struct dev_kqfilter_args *ap)
536 {
537 	return (ENODEV);
538 }
539 
540 int
541 nommap(struct dev_mmap_args *ap)
542 {
543 	return (ENODEV);
544 }
545 
546 int
547 nopoll(struct dev_poll_args *ap)
548 {
549 	ap->a_events = 0;
550 	return(0);
551 }
552 
553 int
554 nostrategy(struct dev_strategy_args *ap)
555 {
556 	struct bio *bio = ap->a_bio;
557 
558 	bio->bio_buf->b_flags |= B_ERROR;
559 	bio->bio_buf->b_error = EOPNOTSUPP;
560 	biodone(bio);
561 	return(0);
562 }
563 
564 int
565 nopsize(struct dev_psize_args *ap)
566 {
567 	ap->a_result = 0;
568 	return(0);
569 }
570 
571 int
572 nodump(struct dev_dump_args *ap)
573 {
574 	return (ENODEV);
575 }
576 
577 /*
578  * XXX this is probably bogus.  Any device that uses it isn't checking the
579  * minor number.
580  */
581 int
582 nullopen(struct dev_open_args *ap)
583 {
584 	return (0);
585 }
586 
587 int
588 nullclose(struct dev_close_args *ap)
589 {
590 	return (0);
591 }
592 
593