xref: /illumos-gate/usr/src/uts/common/io/pseudonex.c (revision 71269a2275bf5a143dad6461eee2710a344e7261)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 
27 /*
28  * Pseudo devices are devices implemented entirely in software; pseudonex
29  * (pseudo) is the traditional nexus for pseudodevices.  Instances are
30  * typically specified via driver.conf files; e.g. a leaf device which
31  * should be attached below pseudonex will have an entry like:
32  *
33  *	name="foo" parent="/pseudo" instance=0;
34  *
35  * pseudonex also supports the devctl (see <sys/devctl.h>) interface via
36  * its :devctl minor node.  This allows priveleged userland applications to
37  * online/offline children of pseudo as needed.
38  *
39  * In general, we discourage widespread use of this tactic, as it may lead to a
40  * proliferation of nodes in /pseudo.  It is preferred that implementors update
41  * pseudo.conf, adding another 'pseudo' nexus child of /pseudo, and then use
42  * that for their collection of device nodes.  To do so, add a driver alias
43  * for the name of the nexus child and a line in pseudo.conf such as:
44  *
45  * 	name="foo" parent="/pseudo" instance=<n> valid-children="bar","baz";
46  *
47  * Setting 'valid-children' is important because we have an annoying problem;
48  * we need to prevent pseudo devices with 'parent="pseudo"' set from binding
49  * to our new pseudonex child node.  A better way might be to teach the
50  * spec-node code to understand that parent="pseudo" really means
51  * parent="/pseudo".
52  *
53  * At some point in the future, it would be desirable to extend the instance
54  * database to include nexus children of pseudo.  Then we could use devctl
55  * or devfs to online nexus children of pseudo, auto-selecting an instance #,
56  * and the instance number selected would be preserved across reboot in
57  * path_to_inst.
58  */
59 
60 #include <sys/types.h>
61 #include <sys/cmn_err.h>
62 #include <sys/conf.h>
63 #include <sys/ddi.h>
64 #include <sys/ddi_impldefs.h>
65 #include <sys/devops.h>
66 #include <sys/instance.h>
67 #include <sys/modctl.h>
68 #include <sys/open.h>
69 #include <sys/stat.h>
70 #include <sys/sunddi.h>
71 #include <sys/sunndi.h>
72 #include <sys/systm.h>
73 #include <sys/mkdev.h>
74 
75 /*
76  * Config information
77  */
78 static int pseudonex_intr_op(dev_info_t *dip, dev_info_t *rdip,
79 	    ddi_intr_op_t op, ddi_intr_handle_impl_t *hdlp, void *result);
80 
81 static int pseudonex_attach(dev_info_t *, ddi_attach_cmd_t);
82 static int pseudonex_detach(dev_info_t *, ddi_detach_cmd_t);
83 static int pseudonex_open(dev_t *, int, int, cred_t *);
84 static int pseudonex_close(dev_t, int, int, cred_t *);
85 static int pseudonex_ioctl(dev_t, int, intptr_t, int, cred_t *, int *);
86 static int pseudonex_ctl(dev_info_t *, dev_info_t *, ddi_ctl_enum_t, void *,
87     void *);
88 
89 static void *pseudonex_state;
90 
91 typedef struct pseudonex_state {
92 	dev_info_t *pnx_devi;
93 } pseudonex_state_t;
94 
95 static struct bus_ops pseudonex_bus_ops = {
96 	BUSO_REV,
97 	nullbusmap,		/* bus_map */
98 	NULL,			/* bus_get_intrspec */
99 	NULL,			/* bus_add_intrspec */
100 	NULL,			/* bus_remove_intrspec */
101 	i_ddi_map_fault,	/* bus_map_fault */
102 	ddi_no_dma_map,		/* bus_dma_map */
103 	ddi_no_dma_allochdl,	/* bus_dma_allochdl */
104 	NULL,			/* bus_dma_freehdl */
105 	NULL,			/* bus_dma_bindhdl */
106 	NULL,			/* bus_dma_unbindhdl */
107 	NULL,			/* bus_dma_flush */
108 	NULL,			/* bus_dma_win */
109 	NULL,			/* bus_dma_ctl */
110 	pseudonex_ctl,		/* bus_ctl */
111 	ddi_bus_prop_op,	/* bus_prop_op */
112 	0,			/* bus_get_eventcookie */
113 	0,			/* bus_add_eventcall */
114 	0,			/* bus_remove_eventcall	*/
115 	0,			/* bus_post_event */
116 	NULL,			/* bus_intr_ctl */
117 	NULL,			/* bus_config */
118 	NULL,			/* bus_unconfig */
119 	NULL,			/* bus_fm_init */
120 	NULL,			/* bus_fm_fini */
121 	NULL,			/* bus_fm_access_enter */
122 	NULL,			/* bus_fm_access_exit */
123 	NULL,			/* bus_power */
124 	pseudonex_intr_op	/* bus_intr_op */
125 };
126 
127 static struct cb_ops pseudonex_cb_ops = {
128 	pseudonex_open,			/* open */
129 	pseudonex_close,		/* close */
130 	nodev,				/* strategy */
131 	nodev,				/* print */
132 	nodev,				/* dump */
133 	nodev,				/* read */
134 	nodev,				/* write */
135 	pseudonex_ioctl,		/* ioctl */
136 	nodev,				/* devmap */
137 	nodev,				/* mmap */
138 	nodev,				/* segmap */
139 	nochpoll,			/* poll */
140 	ddi_prop_op,			/* cb_prop_op */
141 	0,				/* streamtab  */
142 	D_MP | D_NEW | D_HOTPLUG	/* Driver compatibility flag */
143 };
144 
145 static struct dev_ops pseudo_ops = {
146 	DEVO_REV,		/* devo_rev, */
147 	0,			/* refcnt  */
148 	ddi_getinfo_1to1,	/* info */
149 	nulldev,		/* identify */
150 	nulldev,		/* probe */
151 	pseudonex_attach,	/* attach */
152 	pseudonex_detach,	/* detach */
153 	nodev,			/* reset */
154 	&pseudonex_cb_ops,	/* driver operations */
155 	&pseudonex_bus_ops,	/* bus operations */
156 	nulldev,		/* power */
157 	ddi_quiesce_not_needed,		/* quiesce */
158 };
159 
160 /*
161  * Module linkage information for the kernel.
162  */
163 static struct modldrv modldrv = {
164 	&mod_driverops,
165 	"nexus driver for 'pseudo' 1.31",
166 	&pseudo_ops,
167 };
168 
169 static struct modlinkage modlinkage = {
170 	MODREV_1, (void *)&modldrv, NULL
171 };
172 
173 int
174 _init(void)
175 {
176 	int err;
177 
178 	if ((err = ddi_soft_state_init(&pseudonex_state,
179 	    sizeof (pseudonex_state_t), 0)) != 0) {
180 		return (err);
181 	}
182 	if ((err = mod_install(&modlinkage)) != 0) {
183 		ddi_soft_state_fini(&pseudonex_state);
184 		return (err);
185 	}
186 	return (0);
187 }
188 
189 int
190 _fini(void)
191 {
192 	int err;
193 
194 	if ((err = mod_remove(&modlinkage)) != 0)
195 		return (err);
196 	ddi_soft_state_fini(&pseudonex_state);
197 	return (0);
198 }
199 
200 int
201 _info(struct modinfo *modinfop)
202 {
203 	return (mod_info(&modlinkage, modinfop));
204 }
205 
206 /*ARGSUSED*/
207 static int
208 pseudonex_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
209 {
210 	int instance;
211 	pseudonex_state_t *pnx_state;
212 
213 	switch (cmd) {
214 	case DDI_ATTACH:
215 		break;
216 	case DDI_RESUME:
217 		return (DDI_SUCCESS);
218 	default:
219 		return (DDI_FAILURE);
220 	}
221 
222 	/*
223 	 * Save the devi for this instance in the soft_state data.
224 	 */
225 	instance = ddi_get_instance(devi);
226 	if (ddi_soft_state_zalloc(pseudonex_state, instance) != DDI_SUCCESS)
227 		return (DDI_FAILURE);
228 	pnx_state = ddi_get_soft_state(pseudonex_state, instance);
229 	pnx_state->pnx_devi = devi;
230 
231 	if (ddi_create_minor_node(devi, "devctl", S_IFCHR, instance,
232 	    DDI_NT_NEXUS, 0) != DDI_SUCCESS) {
233 		ddi_remove_minor_node(devi, NULL);
234 		ddi_soft_state_free(pseudonex_state, instance);
235 		return (DDI_FAILURE);
236 	}
237 	ddi_report_dev(devi);
238 	return (DDI_SUCCESS);
239 }
240 
241 /*ARGSUSED*/
242 static int
243 pseudonex_detach(dev_info_t *devi, ddi_detach_cmd_t cmd)
244 {
245 	int instance = ddi_get_instance(devi);
246 
247 	if (cmd == DDI_SUSPEND)
248 		return (DDI_SUCCESS);
249 
250 	ddi_remove_minor_node(devi, NULL);
251 	ddi_soft_state_free(pseudonex_state, instance);
252 	return (DDI_SUCCESS);
253 }
254 
255 /*ARGSUSED*/
256 static int
257 pseudonex_open(dev_t *devp, int flags, int otyp, cred_t *credp)
258 {
259 	int instance;
260 
261 	if (otyp != OTYP_CHR)
262 		return (EINVAL);
263 
264 	instance = getminor(*devp);
265 	if (ddi_get_soft_state(pseudonex_state, instance) == NULL)
266 		return (ENXIO);
267 
268 	return (0);
269 }
270 
271 /*ARGSUSED*/
272 static int
273 pseudonex_close(dev_t dev, int flags, int otyp, cred_t *credp)
274 {
275 	int instance;
276 
277 	if (otyp != OTYP_CHR)
278 		return (EINVAL);
279 
280 	instance = getminor(dev);
281 	if (ddi_get_soft_state(pseudonex_state, instance) == NULL)
282 		return (ENXIO);
283 
284 	return (0);
285 }
286 
287 /*ARGSUSED*/
288 static int
289 pseudonex_ioctl(dev_t dev,
290     int cmd, intptr_t arg, int mode, cred_t *cred_p, int *rval_p)
291 {
292 	int instance;
293 	pseudonex_state_t *pnx_state;
294 
295 	instance = getminor(dev);
296 	if ((pnx_state = ddi_get_soft_state(pseudonex_state, instance)) == NULL)
297 		return (ENXIO);
298 	ASSERT(pnx_state->pnx_devi);
299 	return (ndi_devctl_ioctl(pnx_state->pnx_devi, cmd, arg, mode, 0));
300 }
301 
302 /*
303  * pseudonex_intr_op: pseudonex convert an interrupt number to an
304  *			interrupt. NO OP for pseudo drivers.
305  */
306 /*ARGSUSED*/
307 static int
308 pseudonex_intr_op(dev_info_t *dip, dev_info_t *rdip, ddi_intr_op_t op,
309     ddi_intr_handle_impl_t *hdlp, void *result)
310 {
311 	return (DDI_FAILURE);
312 }
313 
314 static int
315 pseudonex_check_assignment(dev_info_t *child, int test_inst)
316 {
317 	dev_info_t	*tdip;
318 	kmutex_t	*dmp;
319 	const char 	*childname = ddi_driver_name(child);
320 	major_t		childmaj = ddi_name_to_major((char *)childname);
321 
322 	dmp = &devnamesp[childmaj].dn_lock;
323 	LOCK_DEV_OPS(dmp);
324 	for (tdip = devnamesp[childmaj].dn_head;
325 	    tdip != NULL; tdip = ddi_get_next(tdip)) {
326 		/* is this the current node? */
327 		if (tdip == child)
328 			continue;
329 		/* is this a duplicate instance? */
330 		if (test_inst == ddi_get_instance(tdip)) {
331 			UNLOCK_DEV_OPS(dmp);
332 			return (DDI_FAILURE);
333 		}
334 	}
335 	UNLOCK_DEV_OPS(dmp);
336 	return (DDI_SUCCESS);
337 }
338 
339 /*
340  * This is a nasty, slow hack.  But we're stuck with it until we do some
341  * major surgery on the instance assignment subsystem, to allow pseudonode
342  * instance assignment to be tracked there.
343  *
344  * To auto-assign an instance number, we exhaustively search the instance
345  * list for each possible instance number until we find one which is unused.
346  */
347 static int
348 pseudonex_auto_assign(dev_info_t *child)
349 {
350 	dev_info_t	*tdip;
351 	kmutex_t	*dmp;
352 	const char 	*childname = ddi_driver_name(child);
353 	major_t		childmaj = ddi_name_to_major((char *)childname);
354 	int inst = 0;
355 
356 	dmp = &devnamesp[childmaj].dn_lock;
357 	LOCK_DEV_OPS(dmp);
358 	for (inst = 0; inst <= MAXMIN32; inst++) {
359 		for (tdip = devnamesp[childmaj].dn_head; tdip != NULL;
360 		    tdip = ddi_get_next(tdip)) {
361 			/* is this the current node? */
362 			if (tdip == child)
363 				continue;
364 			if (inst == ddi_get_instance(tdip)) {
365 				break;
366 			}
367 		}
368 		if (tdip == NULL) {
369 			UNLOCK_DEV_OPS(dmp);
370 			return (inst);
371 		}
372 	}
373 	UNLOCK_DEV_OPS(dmp);
374 	return (-1);
375 }
376 
377 static int
378 pseudonex_ctl(dev_info_t *dip, dev_info_t *rdip, ddi_ctl_enum_t ctlop,
379     void *arg, void *result)
380 {
381 	switch (ctlop) {
382 	case DDI_CTLOPS_REPORTDEV:
383 		if (rdip == NULL)
384 			return (DDI_FAILURE);
385 		cmn_err(CE_CONT, "?pseudo-device: %s%d\n",
386 		    ddi_driver_name(rdip), ddi_get_instance(rdip));
387 		return (DDI_SUCCESS);
388 
389 	case DDI_CTLOPS_INITCHILD:
390 	{
391 		char name[12];	/* enough for a decimal integer */
392 		int instance = -1;
393 		dev_info_t *child = (dev_info_t *)arg;
394 		const char *childname = ddi_driver_name(child);
395 		char **childlist;
396 		uint_t nelems;
397 		int auto_assign = 0;
398 
399 		/*
400 		 * If this pseudonex node has a valid-children property,
401 		 * then that acts as an access control list for children
402 		 * allowed to attach beneath this node.  Honor it.
403 		 */
404 		if (ddi_prop_lookup_string_array(DDI_DEV_T_ANY, dip,
405 		    DDI_PROP_DONTPASS, "valid-children", &childlist,
406 		    &nelems) == DDI_PROP_SUCCESS) {
407 			int i, ok = 0;
408 			for (i = 0; i < nelems; i++) {
409 				if (strcmp(childlist[i], childname) == 0) {
410 					ok = 1;
411 					break;
412 				}
413 			}
414 			ddi_prop_free(childlist);
415 			if (!ok)
416 				return (DDI_FAILURE);
417 		}
418 
419 		/*
420 		 * Look up the "instance" property. If it does not exist,
421 		 * check to see if the "auto-assign-instance" property is set.
422 		 * If not, default to using instance 0; while not ideal, this
423 		 * is a legacy behavior we must continue to support.
424 		 */
425 		instance = ddi_prop_get_int(DDI_DEV_T_ANY, child,
426 		    DDI_PROP_DONTPASS, "instance", -1);
427 		auto_assign = ddi_prop_exists(DDI_DEV_T_ANY, child,
428 		    DDI_PROP_DONTPASS, "auto-assign-instance");
429 		NDI_CONFIG_DEBUG((CE_NOTE,
430 		    "pseudonex: DDI_CTLOPS_INITCHILD(instance=%d, "
431 		    "auto-assign=%d)", instance, auto_assign));
432 
433 		if (instance != -1 && auto_assign != 0) {
434 			NDI_CONFIG_DEBUG((CE_NOTE, "both instance and "
435 			    "auto-assign-instance properties specified. "
436 			    "Node rejected."));
437 			return (DDI_FAILURE);
438 		}
439 
440 		if (instance == -1 && auto_assign == 0) {
441 			/* default to instance 0 if not specified */
442 			NDI_CONFIG_DEBUG((CE_NOTE, "defaulting to 0"));
443 			instance = 0;
444 		}
445 
446 		/*
447 		 * If an instance has been specified, determine if this
448 		 * instance is already in use; if we need to pick an instance,
449 		 * we do it here.
450 		 */
451 		if (auto_assign) {
452 			if ((instance = pseudonex_auto_assign(child)) == -1) {
453 				NDI_CONFIG_DEBUG((CE_NOTE, "failed to "
454 				    "auto-select instance for %s", childname));
455 				return (DDI_FAILURE);
456 			}
457 			NDI_CONFIG_DEBUG((CE_NOTE,
458 			    "auto-selected instance for %s: %d",
459 			    childname, instance));
460 		} else {
461 			if (pseudonex_check_assignment(child, instance) ==
462 			    DDI_FAILURE) {
463 				NDI_CONFIG_DEBUG((CE_WARN,
464 				    "Duplicate instance %d of node \"%s\" "
465 				    "ignored.", instance, childname));
466 				return (DDI_FAILURE);
467 			}
468 			NDI_CONFIG_DEBUG((CE_NOTE,
469 			    "using fixed-assignment instance for %s: %d",
470 			    childname, instance));
471 		}
472 
473 		/*
474 		 * Attach the instance number to the node. This allows
475 		 * us to have multiple instances of the same pseudo
476 		 * device, they will be named 'device@instance'. If this
477 		 * breaks programs, we may need to special-case instance 0
478 		 * into 'device'. Ick. devlinks appears to handle the
479 		 * new names ok, so if only names in /dev are used
480 		 * this may not be necessary.
481 		 */
482 		(void) snprintf(name, sizeof (name), "%d", instance);
483 		DEVI(child)->devi_instance = instance;
484 		ddi_set_name_addr(child, name);
485 		return (DDI_SUCCESS);
486 	}
487 
488 	case DDI_CTLOPS_UNINITCHILD:
489 	{
490 		dev_info_t *child = (dev_info_t *)arg;
491 
492 		NDI_CONFIG_DEBUG((CE_NOTE,
493 		    "DDI_CTLOPS_UNINITCHILD(%s, instance=%d)",
494 		    ddi_driver_name(child), DEVI(child)->devi_instance));
495 
496 		ddi_set_name_addr(child, NULL);
497 
498 		return (DDI_SUCCESS);
499 	}
500 
501 	case DDI_CTLOPS_DMAPMAPC:
502 	case DDI_CTLOPS_REPORTINT:
503 	case DDI_CTLOPS_REGSIZE:
504 	case DDI_CTLOPS_NREGS:
505 	case DDI_CTLOPS_SIDDEV:
506 	case DDI_CTLOPS_SLAVEONLY:
507 	case DDI_CTLOPS_AFFINITY:
508 	case DDI_CTLOPS_POKE:
509 	case DDI_CTLOPS_PEEK:
510 		/*
511 		 * These ops correspond to functions that "shouldn't" be called
512 		 * by a pseudo driver.  So we whine when we're called.
513 		 */
514 		cmn_err(CE_CONT, "%s%d: invalid op (%d) from %s%d\n",
515 		    ddi_driver_name(dip), ddi_get_instance(dip), ctlop,
516 		    ddi_driver_name(rdip), ddi_get_instance(rdip));
517 		return (DDI_FAILURE);
518 
519 	case DDI_CTLOPS_ATTACH:
520 	case DDI_CTLOPS_BTOP:
521 	case DDI_CTLOPS_BTOPR:
522 	case DDI_CTLOPS_DETACH:
523 	case DDI_CTLOPS_DVMAPAGESIZE:
524 	case DDI_CTLOPS_IOMIN:
525 	case DDI_CTLOPS_POWER:
526 	case DDI_CTLOPS_PTOB:
527 	default:
528 		/*
529 		 * The ops that we pass up (default).  We pass up memory
530 		 * allocation oriented ops that we receive - these may be
531 		 * associated with pseudo HBA drivers below us with target
532 		 * drivers below them that use ddi memory allocation
533 		 * interfaces like scsi_alloc_consistent_buf.
534 		 */
535 		return (ddi_ctlops(dip, rdip, ctlop, arg, result));
536 	}
537 }
538