xref: /linux/drivers/s390/cio/chp.c (revision 93d90ad708b8da6efc0e487b66111aa9db7f70c7)
1 /*
2  *    Copyright IBM Corp. 1999, 2010
3  *    Author(s): Cornelia Huck (cornelia.huck@de.ibm.com)
4  *		 Arnd Bergmann (arndb@de.ibm.com)
5  *		 Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
6  */
7 
8 #include <linux/bug.h>
9 #include <linux/workqueue.h>
10 #include <linux/spinlock.h>
11 #include <linux/export.h>
12 #include <linux/sched.h>
13 #include <linux/init.h>
14 #include <linux/jiffies.h>
15 #include <linux/wait.h>
16 #include <linux/mutex.h>
17 #include <linux/errno.h>
18 #include <linux/slab.h>
19 #include <asm/chpid.h>
20 #include <asm/sclp.h>
21 #include <asm/crw.h>
22 
23 #include "cio.h"
24 #include "css.h"
25 #include "ioasm.h"
26 #include "cio_debug.h"
27 #include "chp.h"
28 
29 #define to_channelpath(device) container_of(device, struct channel_path, dev)
30 #define CHP_INFO_UPDATE_INTERVAL	1*HZ
31 
32 enum cfg_task_t {
33 	cfg_none,
34 	cfg_configure,
35 	cfg_deconfigure
36 };
37 
38 /* Map for pending configure tasks. */
39 static enum cfg_task_t chp_cfg_task[__MAX_CSSID + 1][__MAX_CHPID + 1];
40 static DEFINE_MUTEX(cfg_lock);
41 static int cfg_busy;
42 
43 /* Map for channel-path status. */
44 static struct sclp_chp_info chp_info;
45 static DEFINE_MUTEX(info_lock);
46 
47 /* Time after which channel-path status may be outdated. */
48 static unsigned long chp_info_expires;
49 
50 /* Workqueue to perform pending configure tasks. */
51 static struct workqueue_struct *chp_wq;
52 static struct work_struct cfg_work;
53 
54 /* Wait queue for configure completion events. */
55 static wait_queue_head_t cfg_wait_queue;
56 
57 /* Set vary state for given chpid. */
58 static void set_chp_logically_online(struct chp_id chpid, int onoff)
59 {
60 	chpid_to_chp(chpid)->state = onoff;
61 }
62 
63 /* On success return 0 if channel-path is varied offline, 1 if it is varied
64  * online. Return -ENODEV if channel-path is not registered. */
65 int chp_get_status(struct chp_id chpid)
66 {
67 	return (chpid_to_chp(chpid) ? chpid_to_chp(chpid)->state : -ENODEV);
68 }
69 
70 /**
71  * chp_get_sch_opm - return opm for subchannel
72  * @sch: subchannel
73  *
74  * Calculate and return the operational path mask (opm) based on the chpids
75  * used by the subchannel and the status of the associated channel-paths.
76  */
77 u8 chp_get_sch_opm(struct subchannel *sch)
78 {
79 	struct chp_id chpid;
80 	int opm;
81 	int i;
82 
83 	opm = 0;
84 	chp_id_init(&chpid);
85 	for (i = 0; i < 8; i++) {
86 		opm <<= 1;
87 		chpid.id = sch->schib.pmcw.chpid[i];
88 		if (chp_get_status(chpid) != 0)
89 			opm |= 1;
90 	}
91 	return opm;
92 }
93 EXPORT_SYMBOL_GPL(chp_get_sch_opm);
94 
95 /**
96  * chp_is_registered - check if a channel-path is registered
97  * @chpid: channel-path ID
98  *
99  * Return non-zero if a channel-path with the given chpid is registered,
100  * zero otherwise.
101  */
102 int chp_is_registered(struct chp_id chpid)
103 {
104 	return chpid_to_chp(chpid) != NULL;
105 }
106 
107 /*
108  * Function: s390_vary_chpid
109  * Varies the specified chpid online or offline
110  */
111 static int s390_vary_chpid(struct chp_id chpid, int on)
112 {
113 	char dbf_text[15];
114 	int status;
115 
116 	sprintf(dbf_text, on?"varyon%x.%02x":"varyoff%x.%02x", chpid.cssid,
117 		chpid.id);
118 	CIO_TRACE_EVENT(2, dbf_text);
119 
120 	status = chp_get_status(chpid);
121 	if (!on && !status)
122 		return 0;
123 
124 	set_chp_logically_online(chpid, on);
125 	chsc_chp_vary(chpid, on);
126 	return 0;
127 }
128 
129 /*
130  * Channel measurement related functions
131  */
132 static ssize_t chp_measurement_chars_read(struct file *filp,
133 					  struct kobject *kobj,
134 					  struct bin_attribute *bin_attr,
135 					  char *buf, loff_t off, size_t count)
136 {
137 	struct channel_path *chp;
138 	struct device *device;
139 
140 	device = container_of(kobj, struct device, kobj);
141 	chp = to_channelpath(device);
142 	if (!chp->cmg_chars)
143 		return 0;
144 
145 	return memory_read_from_buffer(buf, count, &off,
146 				chp->cmg_chars, sizeof(struct cmg_chars));
147 }
148 
149 static struct bin_attribute chp_measurement_chars_attr = {
150 	.attr = {
151 		.name = "measurement_chars",
152 		.mode = S_IRUSR,
153 	},
154 	.size = sizeof(struct cmg_chars),
155 	.read = chp_measurement_chars_read,
156 };
157 
158 static void chp_measurement_copy_block(struct cmg_entry *buf,
159 				       struct channel_subsystem *css,
160 				       struct chp_id chpid)
161 {
162 	void *area;
163 	struct cmg_entry *entry, reference_buf;
164 	int idx;
165 
166 	if (chpid.id < 128) {
167 		area = css->cub_addr1;
168 		idx = chpid.id;
169 	} else {
170 		area = css->cub_addr2;
171 		idx = chpid.id - 128;
172 	}
173 	entry = area + (idx * sizeof(struct cmg_entry));
174 	do {
175 		memcpy(buf, entry, sizeof(*entry));
176 		memcpy(&reference_buf, entry, sizeof(*entry));
177 	} while (reference_buf.values[0] != buf->values[0]);
178 }
179 
180 static ssize_t chp_measurement_read(struct file *filp, struct kobject *kobj,
181 				    struct bin_attribute *bin_attr,
182 				    char *buf, loff_t off, size_t count)
183 {
184 	struct channel_path *chp;
185 	struct channel_subsystem *css;
186 	struct device *device;
187 	unsigned int size;
188 
189 	device = container_of(kobj, struct device, kobj);
190 	chp = to_channelpath(device);
191 	css = to_css(chp->dev.parent);
192 
193 	size = sizeof(struct cmg_entry);
194 
195 	/* Only allow single reads. */
196 	if (off || count < size)
197 		return 0;
198 	chp_measurement_copy_block((struct cmg_entry *)buf, css, chp->chpid);
199 	count = size;
200 	return count;
201 }
202 
203 static struct bin_attribute chp_measurement_attr = {
204 	.attr = {
205 		.name = "measurement",
206 		.mode = S_IRUSR,
207 	},
208 	.size = sizeof(struct cmg_entry),
209 	.read = chp_measurement_read,
210 };
211 
212 void chp_remove_cmg_attr(struct channel_path *chp)
213 {
214 	device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
215 	device_remove_bin_file(&chp->dev, &chp_measurement_attr);
216 }
217 
218 int chp_add_cmg_attr(struct channel_path *chp)
219 {
220 	int ret;
221 
222 	ret = device_create_bin_file(&chp->dev, &chp_measurement_chars_attr);
223 	if (ret)
224 		return ret;
225 	ret = device_create_bin_file(&chp->dev, &chp_measurement_attr);
226 	if (ret)
227 		device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
228 	return ret;
229 }
230 
231 /*
232  * Files for the channel path entries.
233  */
234 static ssize_t chp_status_show(struct device *dev,
235 			       struct device_attribute *attr, char *buf)
236 {
237 	struct channel_path *chp = to_channelpath(dev);
238 	int status;
239 
240 	mutex_lock(&chp->lock);
241 	status = chp->state;
242 	mutex_unlock(&chp->lock);
243 
244 	return status ? sprintf(buf, "online\n") : sprintf(buf, "offline\n");
245 }
246 
247 static ssize_t chp_status_write(struct device *dev,
248 				struct device_attribute *attr,
249 				const char *buf, size_t count)
250 {
251 	struct channel_path *cp = to_channelpath(dev);
252 	char cmd[10];
253 	int num_args;
254 	int error;
255 
256 	num_args = sscanf(buf, "%5s", cmd);
257 	if (!num_args)
258 		return count;
259 
260 	if (!strncasecmp(cmd, "on", 2) || !strcmp(cmd, "1")) {
261 		mutex_lock(&cp->lock);
262 		error = s390_vary_chpid(cp->chpid, 1);
263 		mutex_unlock(&cp->lock);
264 	} else if (!strncasecmp(cmd, "off", 3) || !strcmp(cmd, "0")) {
265 		mutex_lock(&cp->lock);
266 		error = s390_vary_chpid(cp->chpid, 0);
267 		mutex_unlock(&cp->lock);
268 	} else
269 		error = -EINVAL;
270 
271 	return error < 0 ? error : count;
272 }
273 
274 static DEVICE_ATTR(status, 0644, chp_status_show, chp_status_write);
275 
276 static ssize_t chp_configure_show(struct device *dev,
277 				  struct device_attribute *attr, char *buf)
278 {
279 	struct channel_path *cp;
280 	int status;
281 
282 	cp = to_channelpath(dev);
283 	status = chp_info_get_status(cp->chpid);
284 	if (status < 0)
285 		return status;
286 
287 	return snprintf(buf, PAGE_SIZE, "%d\n", status);
288 }
289 
290 static int cfg_wait_idle(void);
291 
292 static ssize_t chp_configure_write(struct device *dev,
293 				   struct device_attribute *attr,
294 				   const char *buf, size_t count)
295 {
296 	struct channel_path *cp;
297 	int val;
298 	char delim;
299 
300 	if (sscanf(buf, "%d %c", &val, &delim) != 1)
301 		return -EINVAL;
302 	if (val != 0 && val != 1)
303 		return -EINVAL;
304 	cp = to_channelpath(dev);
305 	chp_cfg_schedule(cp->chpid, val);
306 	cfg_wait_idle();
307 
308 	return count;
309 }
310 
311 static DEVICE_ATTR(configure, 0644, chp_configure_show, chp_configure_write);
312 
313 static ssize_t chp_type_show(struct device *dev, struct device_attribute *attr,
314 			     char *buf)
315 {
316 	struct channel_path *chp = to_channelpath(dev);
317 	u8 type;
318 
319 	mutex_lock(&chp->lock);
320 	type = chp->desc.desc;
321 	mutex_unlock(&chp->lock);
322 	return sprintf(buf, "%x\n", type);
323 }
324 
325 static DEVICE_ATTR(type, 0444, chp_type_show, NULL);
326 
327 static ssize_t chp_cmg_show(struct device *dev, struct device_attribute *attr,
328 			    char *buf)
329 {
330 	struct channel_path *chp = to_channelpath(dev);
331 
332 	if (!chp)
333 		return 0;
334 	if (chp->cmg == -1) /* channel measurements not available */
335 		return sprintf(buf, "unknown\n");
336 	return sprintf(buf, "%x\n", chp->cmg);
337 }
338 
339 static DEVICE_ATTR(cmg, 0444, chp_cmg_show, NULL);
340 
341 static ssize_t chp_shared_show(struct device *dev,
342 			       struct device_attribute *attr, char *buf)
343 {
344 	struct channel_path *chp = to_channelpath(dev);
345 
346 	if (!chp)
347 		return 0;
348 	if (chp->shared == -1) /* channel measurements not available */
349 		return sprintf(buf, "unknown\n");
350 	return sprintf(buf, "%x\n", chp->shared);
351 }
352 
353 static DEVICE_ATTR(shared, 0444, chp_shared_show, NULL);
354 
355 static ssize_t chp_chid_show(struct device *dev, struct device_attribute *attr,
356 			     char *buf)
357 {
358 	struct channel_path *chp = to_channelpath(dev);
359 	ssize_t rc;
360 
361 	mutex_lock(&chp->lock);
362 	if (chp->desc_fmt1.flags & 0x10)
363 		rc = sprintf(buf, "%04x\n", chp->desc_fmt1.chid);
364 	else
365 		rc = 0;
366 	mutex_unlock(&chp->lock);
367 
368 	return rc;
369 }
370 static DEVICE_ATTR(chid, 0444, chp_chid_show, NULL);
371 
372 static ssize_t chp_chid_external_show(struct device *dev,
373 				      struct device_attribute *attr, char *buf)
374 {
375 	struct channel_path *chp = to_channelpath(dev);
376 	ssize_t rc;
377 
378 	mutex_lock(&chp->lock);
379 	if (chp->desc_fmt1.flags & 0x10)
380 		rc = sprintf(buf, "%x\n", chp->desc_fmt1.flags & 0x8 ? 1 : 0);
381 	else
382 		rc = 0;
383 	mutex_unlock(&chp->lock);
384 
385 	return rc;
386 }
387 static DEVICE_ATTR(chid_external, 0444, chp_chid_external_show, NULL);
388 
389 static struct attribute *chp_attrs[] = {
390 	&dev_attr_status.attr,
391 	&dev_attr_configure.attr,
392 	&dev_attr_type.attr,
393 	&dev_attr_cmg.attr,
394 	&dev_attr_shared.attr,
395 	&dev_attr_chid.attr,
396 	&dev_attr_chid_external.attr,
397 	NULL,
398 };
399 static struct attribute_group chp_attr_group = {
400 	.attrs = chp_attrs,
401 };
402 static const struct attribute_group *chp_attr_groups[] = {
403 	&chp_attr_group,
404 	NULL,
405 };
406 
407 static void chp_release(struct device *dev)
408 {
409 	struct channel_path *cp;
410 
411 	cp = to_channelpath(dev);
412 	kfree(cp);
413 }
414 
415 /**
416  * chp_update_desc - update channel-path description
417  * @chp - channel-path
418  *
419  * Update the channel-path description of the specified channel-path.
420  * Return zero on success, non-zero otherwise.
421  */
422 int chp_update_desc(struct channel_path *chp)
423 {
424 	int rc;
425 
426 	rc = chsc_determine_base_channel_path_desc(chp->chpid, &chp->desc);
427 	if (rc)
428 		return rc;
429 
430 	rc = chsc_determine_fmt1_channel_path_desc(chp->chpid, &chp->desc_fmt1);
431 
432 	return rc;
433 }
434 
435 /**
436  * chp_new - register a new channel-path
437  * @chpid - channel-path ID
438  *
439  * Create and register data structure representing new channel-path. Return
440  * zero on success, non-zero otherwise.
441  */
442 int chp_new(struct chp_id chpid)
443 {
444 	struct channel_path *chp;
445 	int ret;
446 
447 	if (chp_is_registered(chpid))
448 		return 0;
449 	chp = kzalloc(sizeof(struct channel_path), GFP_KERNEL);
450 	if (!chp)
451 		return -ENOMEM;
452 
453 	/* fill in status, etc. */
454 	chp->chpid = chpid;
455 	chp->state = 1;
456 	chp->dev.parent = &channel_subsystems[chpid.cssid]->device;
457 	chp->dev.groups = chp_attr_groups;
458 	chp->dev.release = chp_release;
459 	mutex_init(&chp->lock);
460 
461 	/* Obtain channel path description and fill it in. */
462 	ret = chp_update_desc(chp);
463 	if (ret)
464 		goto out_free;
465 	if ((chp->desc.flags & 0x80) == 0) {
466 		ret = -ENODEV;
467 		goto out_free;
468 	}
469 	/* Get channel-measurement characteristics. */
470 	if (css_chsc_characteristics.scmc && css_chsc_characteristics.secm) {
471 		ret = chsc_get_channel_measurement_chars(chp);
472 		if (ret)
473 			goto out_free;
474 	} else {
475 		chp->cmg = -1;
476 	}
477 	dev_set_name(&chp->dev, "chp%x.%02x", chpid.cssid, chpid.id);
478 
479 	/* make it known to the system */
480 	ret = device_register(&chp->dev);
481 	if (ret) {
482 		CIO_MSG_EVENT(0, "Could not register chp%x.%02x: %d\n",
483 			      chpid.cssid, chpid.id, ret);
484 		put_device(&chp->dev);
485 		goto out;
486 	}
487 	mutex_lock(&channel_subsystems[chpid.cssid]->mutex);
488 	if (channel_subsystems[chpid.cssid]->cm_enabled) {
489 		ret = chp_add_cmg_attr(chp);
490 		if (ret) {
491 			device_unregister(&chp->dev);
492 			mutex_unlock(&channel_subsystems[chpid.cssid]->mutex);
493 			goto out;
494 		}
495 	}
496 	channel_subsystems[chpid.cssid]->chps[chpid.id] = chp;
497 	mutex_unlock(&channel_subsystems[chpid.cssid]->mutex);
498 	goto out;
499 out_free:
500 	kfree(chp);
501 out:
502 	return ret;
503 }
504 
505 /**
506  * chp_get_chp_desc - return newly allocated channel-path description
507  * @chpid: channel-path ID
508  *
509  * On success return a newly allocated copy of the channel-path description
510  * data associated with the given channel-path ID. Return %NULL on error.
511  */
512 struct channel_path_desc *chp_get_chp_desc(struct chp_id chpid)
513 {
514 	struct channel_path *chp;
515 	struct channel_path_desc *desc;
516 
517 	chp = chpid_to_chp(chpid);
518 	if (!chp)
519 		return NULL;
520 	desc = kmalloc(sizeof(struct channel_path_desc), GFP_KERNEL);
521 	if (!desc)
522 		return NULL;
523 
524 	mutex_lock(&chp->lock);
525 	memcpy(desc, &chp->desc, sizeof(struct channel_path_desc));
526 	mutex_unlock(&chp->lock);
527 	return desc;
528 }
529 
530 /**
531  * chp_process_crw - process channel-path status change
532  * @crw0: channel report-word to handler
533  * @crw1: second channel-report word (always NULL)
534  * @overflow: crw overflow indication
535  *
536  * Handle channel-report-words indicating that the status of a channel-path
537  * has changed.
538  */
539 static void chp_process_crw(struct crw *crw0, struct crw *crw1,
540 			    int overflow)
541 {
542 	struct chp_id chpid;
543 
544 	if (overflow) {
545 		css_schedule_eval_all();
546 		return;
547 	}
548 	CIO_CRW_EVENT(2, "CRW reports slct=%d, oflw=%d, "
549 		      "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
550 		      crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
551 		      crw0->erc, crw0->rsid);
552 	/*
553 	 * Check for solicited machine checks. These are
554 	 * created by reset channel path and need not be
555 	 * handled here.
556 	 */
557 	if (crw0->slct) {
558 		CIO_CRW_EVENT(2, "solicited machine check for "
559 			      "channel path %02X\n", crw0->rsid);
560 		return;
561 	}
562 	chp_id_init(&chpid);
563 	chpid.id = crw0->rsid;
564 	switch (crw0->erc) {
565 	case CRW_ERC_IPARM: /* Path has come. */
566 		if (!chp_is_registered(chpid))
567 			chp_new(chpid);
568 		chsc_chp_online(chpid);
569 		break;
570 	case CRW_ERC_PERRI: /* Path has gone. */
571 	case CRW_ERC_PERRN:
572 		chsc_chp_offline(chpid);
573 		break;
574 	default:
575 		CIO_CRW_EVENT(2, "Don't know how to handle erc=%x\n",
576 			      crw0->erc);
577 	}
578 }
579 
580 int chp_ssd_get_mask(struct chsc_ssd_info *ssd, struct chp_link *link)
581 {
582 	int i;
583 	int mask;
584 
585 	for (i = 0; i < 8; i++) {
586 		mask = 0x80 >> i;
587 		if (!(ssd->path_mask & mask))
588 			continue;
589 		if (!chp_id_is_equal(&ssd->chpid[i], &link->chpid))
590 			continue;
591 		if ((ssd->fla_valid_mask & mask) &&
592 		    ((ssd->fla[i] & link->fla_mask) != link->fla))
593 			continue;
594 		return mask;
595 	}
596 	return 0;
597 }
598 EXPORT_SYMBOL_GPL(chp_ssd_get_mask);
599 
600 static inline int info_bit_num(struct chp_id id)
601 {
602 	return id.id + id.cssid * (__MAX_CHPID + 1);
603 }
604 
605 /* Force chp_info refresh on next call to info_validate(). */
606 static void info_expire(void)
607 {
608 	mutex_lock(&info_lock);
609 	chp_info_expires = jiffies - 1;
610 	mutex_unlock(&info_lock);
611 }
612 
613 /* Ensure that chp_info is up-to-date. */
614 static int info_update(void)
615 {
616 	int rc;
617 
618 	mutex_lock(&info_lock);
619 	rc = 0;
620 	if (time_after(jiffies, chp_info_expires)) {
621 		/* Data is too old, update. */
622 		rc = sclp_chp_read_info(&chp_info);
623 		chp_info_expires = jiffies + CHP_INFO_UPDATE_INTERVAL ;
624 	}
625 	mutex_unlock(&info_lock);
626 
627 	return rc;
628 }
629 
630 /**
631  * chp_info_get_status - retrieve configure status of a channel-path
632  * @chpid: channel-path ID
633  *
634  * On success, return 0 for standby, 1 for configured, 2 for reserved,
635  * 3 for not recognized. Return negative error code on error.
636  */
637 int chp_info_get_status(struct chp_id chpid)
638 {
639 	int rc;
640 	int bit;
641 
642 	rc = info_update();
643 	if (rc)
644 		return rc;
645 
646 	bit = info_bit_num(chpid);
647 	mutex_lock(&info_lock);
648 	if (!chp_test_bit(chp_info.recognized, bit))
649 		rc = CHP_STATUS_NOT_RECOGNIZED;
650 	else if (chp_test_bit(chp_info.configured, bit))
651 		rc = CHP_STATUS_CONFIGURED;
652 	else if (chp_test_bit(chp_info.standby, bit))
653 		rc = CHP_STATUS_STANDBY;
654 	else
655 		rc = CHP_STATUS_RESERVED;
656 	mutex_unlock(&info_lock);
657 
658 	return rc;
659 }
660 
661 /* Return configure task for chpid. */
662 static enum cfg_task_t cfg_get_task(struct chp_id chpid)
663 {
664 	return chp_cfg_task[chpid.cssid][chpid.id];
665 }
666 
667 /* Set configure task for chpid. */
668 static void cfg_set_task(struct chp_id chpid, enum cfg_task_t cfg)
669 {
670 	chp_cfg_task[chpid.cssid][chpid.id] = cfg;
671 }
672 
673 /* Perform one configure/deconfigure request. Reschedule work function until
674  * last request. */
675 static void cfg_func(struct work_struct *work)
676 {
677 	struct chp_id chpid;
678 	enum cfg_task_t t;
679 	int rc;
680 
681 	mutex_lock(&cfg_lock);
682 	t = cfg_none;
683 	chp_id_for_each(&chpid) {
684 		t = cfg_get_task(chpid);
685 		if (t != cfg_none) {
686 			cfg_set_task(chpid, cfg_none);
687 			break;
688 		}
689 	}
690 	mutex_unlock(&cfg_lock);
691 
692 	switch (t) {
693 	case cfg_configure:
694 		rc = sclp_chp_configure(chpid);
695 		if (rc)
696 			CIO_MSG_EVENT(2, "chp: sclp_chp_configure(%x.%02x)="
697 				      "%d\n", chpid.cssid, chpid.id, rc);
698 		else {
699 			info_expire();
700 			chsc_chp_online(chpid);
701 		}
702 		break;
703 	case cfg_deconfigure:
704 		rc = sclp_chp_deconfigure(chpid);
705 		if (rc)
706 			CIO_MSG_EVENT(2, "chp: sclp_chp_deconfigure(%x.%02x)="
707 				      "%d\n", chpid.cssid, chpid.id, rc);
708 		else {
709 			info_expire();
710 			chsc_chp_offline(chpid);
711 		}
712 		break;
713 	case cfg_none:
714 		/* Get updated information after last change. */
715 		info_update();
716 		mutex_lock(&cfg_lock);
717 		cfg_busy = 0;
718 		mutex_unlock(&cfg_lock);
719 		wake_up_interruptible(&cfg_wait_queue);
720 		return;
721 	}
722 	queue_work(chp_wq, &cfg_work);
723 }
724 
725 /**
726  * chp_cfg_schedule - schedule chpid configuration request
727  * @chpid - channel-path ID
728  * @configure - Non-zero for configure, zero for deconfigure
729  *
730  * Schedule a channel-path configuration/deconfiguration request.
731  */
732 void chp_cfg_schedule(struct chp_id chpid, int configure)
733 {
734 	CIO_MSG_EVENT(2, "chp_cfg_sched%x.%02x=%d\n", chpid.cssid, chpid.id,
735 		      configure);
736 	mutex_lock(&cfg_lock);
737 	cfg_set_task(chpid, configure ? cfg_configure : cfg_deconfigure);
738 	cfg_busy = 1;
739 	mutex_unlock(&cfg_lock);
740 	queue_work(chp_wq, &cfg_work);
741 }
742 
743 /**
744  * chp_cfg_cancel_deconfigure - cancel chpid deconfiguration request
745  * @chpid - channel-path ID
746  *
747  * Cancel an active channel-path deconfiguration request if it has not yet
748  * been performed.
749  */
750 void chp_cfg_cancel_deconfigure(struct chp_id chpid)
751 {
752 	CIO_MSG_EVENT(2, "chp_cfg_cancel:%x.%02x\n", chpid.cssid, chpid.id);
753 	mutex_lock(&cfg_lock);
754 	if (cfg_get_task(chpid) == cfg_deconfigure)
755 		cfg_set_task(chpid, cfg_none);
756 	mutex_unlock(&cfg_lock);
757 }
758 
759 static int cfg_wait_idle(void)
760 {
761 	if (wait_event_interruptible(cfg_wait_queue, !cfg_busy))
762 		return -ERESTARTSYS;
763 	return 0;
764 }
765 
766 static int __init chp_init(void)
767 {
768 	struct chp_id chpid;
769 	int ret;
770 
771 	ret = crw_register_handler(CRW_RSC_CPATH, chp_process_crw);
772 	if (ret)
773 		return ret;
774 	chp_wq = create_singlethread_workqueue("cio_chp");
775 	if (!chp_wq) {
776 		crw_unregister_handler(CRW_RSC_CPATH);
777 		return -ENOMEM;
778 	}
779 	INIT_WORK(&cfg_work, cfg_func);
780 	init_waitqueue_head(&cfg_wait_queue);
781 	if (info_update())
782 		return 0;
783 	/* Register available channel-paths. */
784 	chp_id_for_each(&chpid) {
785 		if (chp_info_get_status(chpid) != CHP_STATUS_NOT_RECOGNIZED)
786 			chp_new(chpid);
787 	}
788 
789 	return 0;
790 }
791 
792 subsys_initcall(chp_init);
793