xref: /openbmc/linux/drivers/s390/cio/chp.c (revision d3964221)
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_SPINLOCK(cfg_lock);
41 
42 /* Map for channel-path status. */
43 static struct sclp_chp_info chp_info;
44 static DEFINE_MUTEX(info_lock);
45 
46 /* Time after which channel-path status may be outdated. */
47 static unsigned long chp_info_expires;
48 
49 static struct work_struct cfg_work;
50 
51 /* Wait queue for configure completion events. */
52 static wait_queue_head_t cfg_wait_queue;
53 
54 /* Set vary state for given chpid. */
55 static void set_chp_logically_online(struct chp_id chpid, int onoff)
56 {
57 	chpid_to_chp(chpid)->state = onoff;
58 }
59 
60 /* On success return 0 if channel-path is varied offline, 1 if it is varied
61  * online. Return -ENODEV if channel-path is not registered. */
62 int chp_get_status(struct chp_id chpid)
63 {
64 	return (chpid_to_chp(chpid) ? chpid_to_chp(chpid)->state : -ENODEV);
65 }
66 
67 /**
68  * chp_get_sch_opm - return opm for subchannel
69  * @sch: subchannel
70  *
71  * Calculate and return the operational path mask (opm) based on the chpids
72  * used by the subchannel and the status of the associated channel-paths.
73  */
74 u8 chp_get_sch_opm(struct subchannel *sch)
75 {
76 	struct chp_id chpid;
77 	int opm;
78 	int i;
79 
80 	opm = 0;
81 	chp_id_init(&chpid);
82 	for (i = 0; i < 8; i++) {
83 		opm <<= 1;
84 		chpid.id = sch->schib.pmcw.chpid[i];
85 		if (chp_get_status(chpid) != 0)
86 			opm |= 1;
87 	}
88 	return opm;
89 }
90 EXPORT_SYMBOL_GPL(chp_get_sch_opm);
91 
92 /**
93  * chp_is_registered - check if a channel-path is registered
94  * @chpid: channel-path ID
95  *
96  * Return non-zero if a channel-path with the given chpid is registered,
97  * zero otherwise.
98  */
99 int chp_is_registered(struct chp_id chpid)
100 {
101 	return chpid_to_chp(chpid) != NULL;
102 }
103 
104 /*
105  * Function: s390_vary_chpid
106  * Varies the specified chpid online or offline
107  */
108 static int s390_vary_chpid(struct chp_id chpid, int on)
109 {
110 	char dbf_text[15];
111 	int status;
112 
113 	sprintf(dbf_text, on?"varyon%x.%02x":"varyoff%x.%02x", chpid.cssid,
114 		chpid.id);
115 	CIO_TRACE_EVENT(2, dbf_text);
116 
117 	status = chp_get_status(chpid);
118 	if (!on && !status)
119 		return 0;
120 
121 	set_chp_logically_online(chpid, on);
122 	chsc_chp_vary(chpid, on);
123 	return 0;
124 }
125 
126 /*
127  * Channel measurement related functions
128  */
129 static ssize_t chp_measurement_chars_read(struct file *filp,
130 					  struct kobject *kobj,
131 					  struct bin_attribute *bin_attr,
132 					  char *buf, loff_t off, size_t count)
133 {
134 	struct channel_path *chp;
135 	struct device *device;
136 
137 	device = container_of(kobj, struct device, kobj);
138 	chp = to_channelpath(device);
139 	if (chp->cmg == -1)
140 		return 0;
141 
142 	return memory_read_from_buffer(buf, count, &off, &chp->cmg_chars,
143 				       sizeof(chp->cmg_chars));
144 }
145 
146 static const struct bin_attribute chp_measurement_chars_attr = {
147 	.attr = {
148 		.name = "measurement_chars",
149 		.mode = S_IRUSR,
150 	},
151 	.size = sizeof(struct cmg_chars),
152 	.read = chp_measurement_chars_read,
153 };
154 
155 static void chp_measurement_copy_block(struct cmg_entry *buf,
156 				       struct channel_subsystem *css,
157 				       struct chp_id chpid)
158 {
159 	void *area;
160 	struct cmg_entry *entry, reference_buf;
161 	int idx;
162 
163 	if (chpid.id < 128) {
164 		area = css->cub_addr1;
165 		idx = chpid.id;
166 	} else {
167 		area = css->cub_addr2;
168 		idx = chpid.id - 128;
169 	}
170 	entry = area + (idx * sizeof(struct cmg_entry));
171 	do {
172 		memcpy(buf, entry, sizeof(*entry));
173 		memcpy(&reference_buf, entry, sizeof(*entry));
174 	} while (reference_buf.values[0] != buf->values[0]);
175 }
176 
177 static ssize_t chp_measurement_read(struct file *filp, struct kobject *kobj,
178 				    struct bin_attribute *bin_attr,
179 				    char *buf, loff_t off, size_t count)
180 {
181 	struct channel_path *chp;
182 	struct channel_subsystem *css;
183 	struct device *device;
184 	unsigned int size;
185 
186 	device = container_of(kobj, struct device, kobj);
187 	chp = to_channelpath(device);
188 	css = to_css(chp->dev.parent);
189 
190 	size = sizeof(struct cmg_entry);
191 
192 	/* Only allow single reads. */
193 	if (off || count < size)
194 		return 0;
195 	chp_measurement_copy_block((struct cmg_entry *)buf, css, chp->chpid);
196 	count = size;
197 	return count;
198 }
199 
200 static const struct bin_attribute chp_measurement_attr = {
201 	.attr = {
202 		.name = "measurement",
203 		.mode = S_IRUSR,
204 	},
205 	.size = sizeof(struct cmg_entry),
206 	.read = chp_measurement_read,
207 };
208 
209 void chp_remove_cmg_attr(struct channel_path *chp)
210 {
211 	device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
212 	device_remove_bin_file(&chp->dev, &chp_measurement_attr);
213 }
214 
215 int chp_add_cmg_attr(struct channel_path *chp)
216 {
217 	int ret;
218 
219 	ret = device_create_bin_file(&chp->dev, &chp_measurement_chars_attr);
220 	if (ret)
221 		return ret;
222 	ret = device_create_bin_file(&chp->dev, &chp_measurement_attr);
223 	if (ret)
224 		device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
225 	return ret;
226 }
227 
228 /*
229  * Files for the channel path entries.
230  */
231 static ssize_t chp_status_show(struct device *dev,
232 			       struct device_attribute *attr, char *buf)
233 {
234 	struct channel_path *chp = to_channelpath(dev);
235 	int status;
236 
237 	mutex_lock(&chp->lock);
238 	status = chp->state;
239 	mutex_unlock(&chp->lock);
240 
241 	return status ? sprintf(buf, "online\n") : sprintf(buf, "offline\n");
242 }
243 
244 static ssize_t chp_status_write(struct device *dev,
245 				struct device_attribute *attr,
246 				const char *buf, size_t count)
247 {
248 	struct channel_path *cp = to_channelpath(dev);
249 	char cmd[10];
250 	int num_args;
251 	int error;
252 
253 	num_args = sscanf(buf, "%5s", cmd);
254 	if (!num_args)
255 		return count;
256 
257 	if (!strncasecmp(cmd, "on", 2) || !strcmp(cmd, "1")) {
258 		mutex_lock(&cp->lock);
259 		error = s390_vary_chpid(cp->chpid, 1);
260 		mutex_unlock(&cp->lock);
261 	} else if (!strncasecmp(cmd, "off", 3) || !strcmp(cmd, "0")) {
262 		mutex_lock(&cp->lock);
263 		error = s390_vary_chpid(cp->chpid, 0);
264 		mutex_unlock(&cp->lock);
265 	} else
266 		error = -EINVAL;
267 
268 	return error < 0 ? error : count;
269 }
270 
271 static DEVICE_ATTR(status, 0644, chp_status_show, chp_status_write);
272 
273 static ssize_t chp_configure_show(struct device *dev,
274 				  struct device_attribute *attr, char *buf)
275 {
276 	struct channel_path *cp;
277 	int status;
278 
279 	cp = to_channelpath(dev);
280 	status = chp_info_get_status(cp->chpid);
281 	if (status < 0)
282 		return status;
283 
284 	return snprintf(buf, PAGE_SIZE, "%d\n", status);
285 }
286 
287 static int cfg_wait_idle(void);
288 
289 static ssize_t chp_configure_write(struct device *dev,
290 				   struct device_attribute *attr,
291 				   const char *buf, size_t count)
292 {
293 	struct channel_path *cp;
294 	int val;
295 	char delim;
296 
297 	if (sscanf(buf, "%d %c", &val, &delim) != 1)
298 		return -EINVAL;
299 	if (val != 0 && val != 1)
300 		return -EINVAL;
301 	cp = to_channelpath(dev);
302 	chp_cfg_schedule(cp->chpid, val);
303 	cfg_wait_idle();
304 
305 	return count;
306 }
307 
308 static DEVICE_ATTR(configure, 0644, chp_configure_show, chp_configure_write);
309 
310 static ssize_t chp_type_show(struct device *dev, struct device_attribute *attr,
311 			     char *buf)
312 {
313 	struct channel_path *chp = to_channelpath(dev);
314 	u8 type;
315 
316 	mutex_lock(&chp->lock);
317 	type = chp->desc.desc;
318 	mutex_unlock(&chp->lock);
319 	return sprintf(buf, "%x\n", type);
320 }
321 
322 static DEVICE_ATTR(type, 0444, chp_type_show, NULL);
323 
324 static ssize_t chp_cmg_show(struct device *dev, struct device_attribute *attr,
325 			    char *buf)
326 {
327 	struct channel_path *chp = to_channelpath(dev);
328 
329 	if (!chp)
330 		return 0;
331 	if (chp->cmg == -1) /* channel measurements not available */
332 		return sprintf(buf, "unknown\n");
333 	return sprintf(buf, "%x\n", chp->cmg);
334 }
335 
336 static DEVICE_ATTR(cmg, 0444, chp_cmg_show, NULL);
337 
338 static ssize_t chp_shared_show(struct device *dev,
339 			       struct device_attribute *attr, char *buf)
340 {
341 	struct channel_path *chp = to_channelpath(dev);
342 
343 	if (!chp)
344 		return 0;
345 	if (chp->shared == -1) /* channel measurements not available */
346 		return sprintf(buf, "unknown\n");
347 	return sprintf(buf, "%x\n", chp->shared);
348 }
349 
350 static DEVICE_ATTR(shared, 0444, chp_shared_show, NULL);
351 
352 static ssize_t chp_chid_show(struct device *dev, struct device_attribute *attr,
353 			     char *buf)
354 {
355 	struct channel_path *chp = to_channelpath(dev);
356 	ssize_t rc;
357 
358 	mutex_lock(&chp->lock);
359 	if (chp->desc_fmt1.flags & 0x10)
360 		rc = sprintf(buf, "%04x\n", chp->desc_fmt1.chid);
361 	else
362 		rc = 0;
363 	mutex_unlock(&chp->lock);
364 
365 	return rc;
366 }
367 static DEVICE_ATTR(chid, 0444, chp_chid_show, NULL);
368 
369 static ssize_t chp_chid_external_show(struct device *dev,
370 				      struct device_attribute *attr, char *buf)
371 {
372 	struct channel_path *chp = to_channelpath(dev);
373 	ssize_t rc;
374 
375 	mutex_lock(&chp->lock);
376 	if (chp->desc_fmt1.flags & 0x10)
377 		rc = sprintf(buf, "%x\n", chp->desc_fmt1.flags & 0x8 ? 1 : 0);
378 	else
379 		rc = 0;
380 	mutex_unlock(&chp->lock);
381 
382 	return rc;
383 }
384 static DEVICE_ATTR(chid_external, 0444, chp_chid_external_show, NULL);
385 
386 static struct attribute *chp_attrs[] = {
387 	&dev_attr_status.attr,
388 	&dev_attr_configure.attr,
389 	&dev_attr_type.attr,
390 	&dev_attr_cmg.attr,
391 	&dev_attr_shared.attr,
392 	&dev_attr_chid.attr,
393 	&dev_attr_chid_external.attr,
394 	NULL,
395 };
396 static struct attribute_group chp_attr_group = {
397 	.attrs = chp_attrs,
398 };
399 static const struct attribute_group *chp_attr_groups[] = {
400 	&chp_attr_group,
401 	NULL,
402 };
403 
404 static void chp_release(struct device *dev)
405 {
406 	struct channel_path *cp;
407 
408 	cp = to_channelpath(dev);
409 	kfree(cp);
410 }
411 
412 /**
413  * chp_update_desc - update channel-path description
414  * @chp - channel-path
415  *
416  * Update the channel-path description of the specified channel-path
417  * including channel measurement related information.
418  * Return zero on success, non-zero otherwise.
419  */
420 int chp_update_desc(struct channel_path *chp)
421 {
422 	int rc;
423 
424 	rc = chsc_determine_base_channel_path_desc(chp->chpid, &chp->desc);
425 	if (rc)
426 		return rc;
427 
428 	/*
429 	 * Fetching the following data is optional. Not all machines or
430 	 * hypervisors implement the required chsc commands.
431 	 */
432 	chsc_determine_fmt1_channel_path_desc(chp->chpid, &chp->desc_fmt1);
433 	chsc_get_channel_measurement_chars(chp);
434 
435 	return 0;
436 }
437 
438 /**
439  * chp_new - register a new channel-path
440  * @chpid - channel-path ID
441  *
442  * Create and register data structure representing new channel-path. Return
443  * zero on success, non-zero otherwise.
444  */
445 int chp_new(struct chp_id chpid)
446 {
447 	struct channel_subsystem *css = css_by_id(chpid.cssid);
448 	struct channel_path *chp;
449 	int ret;
450 
451 	if (chp_is_registered(chpid))
452 		return 0;
453 	chp = kzalloc(sizeof(struct channel_path), GFP_KERNEL);
454 	if (!chp)
455 		return -ENOMEM;
456 
457 	/* fill in status, etc. */
458 	chp->chpid = chpid;
459 	chp->state = 1;
460 	chp->dev.parent = &css->device;
461 	chp->dev.groups = chp_attr_groups;
462 	chp->dev.release = chp_release;
463 	mutex_init(&chp->lock);
464 
465 	/* Obtain channel path description and fill it in. */
466 	ret = chp_update_desc(chp);
467 	if (ret)
468 		goto out_free;
469 	if ((chp->desc.flags & 0x80) == 0) {
470 		ret = -ENODEV;
471 		goto out_free;
472 	}
473 	dev_set_name(&chp->dev, "chp%x.%02x", chpid.cssid, chpid.id);
474 
475 	/* make it known to the system */
476 	ret = device_register(&chp->dev);
477 	if (ret) {
478 		CIO_MSG_EVENT(0, "Could not register chp%x.%02x: %d\n",
479 			      chpid.cssid, chpid.id, ret);
480 		put_device(&chp->dev);
481 		goto out;
482 	}
483 	mutex_lock(&css->mutex);
484 	if (css->cm_enabled) {
485 		ret = chp_add_cmg_attr(chp);
486 		if (ret) {
487 			device_unregister(&chp->dev);
488 			mutex_unlock(&css->mutex);
489 			goto out;
490 		}
491 	}
492 	css->chps[chpid.id] = chp;
493 	mutex_unlock(&css->mutex);
494 	goto out;
495 out_free:
496 	kfree(chp);
497 out:
498 	return ret;
499 }
500 
501 /**
502  * chp_get_chp_desc - return newly allocated channel-path description
503  * @chpid: channel-path ID
504  *
505  * On success return a newly allocated copy of the channel-path description
506  * data associated with the given channel-path ID. Return %NULL on error.
507  */
508 struct channel_path_desc *chp_get_chp_desc(struct chp_id chpid)
509 {
510 	struct channel_path *chp;
511 	struct channel_path_desc *desc;
512 
513 	chp = chpid_to_chp(chpid);
514 	if (!chp)
515 		return NULL;
516 	desc = kmalloc(sizeof(struct channel_path_desc), GFP_KERNEL);
517 	if (!desc)
518 		return NULL;
519 
520 	mutex_lock(&chp->lock);
521 	memcpy(desc, &chp->desc, sizeof(struct channel_path_desc));
522 	mutex_unlock(&chp->lock);
523 	return desc;
524 }
525 
526 /**
527  * chp_process_crw - process channel-path status change
528  * @crw0: channel report-word to handler
529  * @crw1: second channel-report word (always NULL)
530  * @overflow: crw overflow indication
531  *
532  * Handle channel-report-words indicating that the status of a channel-path
533  * has changed.
534  */
535 static void chp_process_crw(struct crw *crw0, struct crw *crw1,
536 			    int overflow)
537 {
538 	struct chp_id chpid;
539 
540 	if (overflow) {
541 		css_schedule_eval_all();
542 		return;
543 	}
544 	CIO_CRW_EVENT(2, "CRW reports slct=%d, oflw=%d, "
545 		      "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
546 		      crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
547 		      crw0->erc, crw0->rsid);
548 	/*
549 	 * Check for solicited machine checks. These are
550 	 * created by reset channel path and need not be
551 	 * handled here.
552 	 */
553 	if (crw0->slct) {
554 		CIO_CRW_EVENT(2, "solicited machine check for "
555 			      "channel path %02X\n", crw0->rsid);
556 		return;
557 	}
558 	chp_id_init(&chpid);
559 	chpid.id = crw0->rsid;
560 	switch (crw0->erc) {
561 	case CRW_ERC_IPARM: /* Path has come. */
562 	case CRW_ERC_INIT:
563 		if (!chp_is_registered(chpid))
564 			chp_new(chpid);
565 		chsc_chp_online(chpid);
566 		break;
567 	case CRW_ERC_PERRI: /* Path has gone. */
568 	case CRW_ERC_PERRN:
569 		chsc_chp_offline(chpid);
570 		break;
571 	default:
572 		CIO_CRW_EVENT(2, "Don't know how to handle erc=%x\n",
573 			      crw0->erc);
574 	}
575 }
576 
577 int chp_ssd_get_mask(struct chsc_ssd_info *ssd, struct chp_link *link)
578 {
579 	int i;
580 	int mask;
581 
582 	for (i = 0; i < 8; i++) {
583 		mask = 0x80 >> i;
584 		if (!(ssd->path_mask & mask))
585 			continue;
586 		if (!chp_id_is_equal(&ssd->chpid[i], &link->chpid))
587 			continue;
588 		if ((ssd->fla_valid_mask & mask) &&
589 		    ((ssd->fla[i] & link->fla_mask) != link->fla))
590 			continue;
591 		return mask;
592 	}
593 	return 0;
594 }
595 EXPORT_SYMBOL_GPL(chp_ssd_get_mask);
596 
597 static inline int info_bit_num(struct chp_id id)
598 {
599 	return id.id + id.cssid * (__MAX_CHPID + 1);
600 }
601 
602 /* Force chp_info refresh on next call to info_validate(). */
603 static void info_expire(void)
604 {
605 	mutex_lock(&info_lock);
606 	chp_info_expires = jiffies - 1;
607 	mutex_unlock(&info_lock);
608 }
609 
610 /* Ensure that chp_info is up-to-date. */
611 static int info_update(void)
612 {
613 	int rc;
614 
615 	mutex_lock(&info_lock);
616 	rc = 0;
617 	if (time_after(jiffies, chp_info_expires)) {
618 		/* Data is too old, update. */
619 		rc = sclp_chp_read_info(&chp_info);
620 		chp_info_expires = jiffies + CHP_INFO_UPDATE_INTERVAL ;
621 	}
622 	mutex_unlock(&info_lock);
623 
624 	return rc;
625 }
626 
627 /**
628  * chp_info_get_status - retrieve configure status of a channel-path
629  * @chpid: channel-path ID
630  *
631  * On success, return 0 for standby, 1 for configured, 2 for reserved,
632  * 3 for not recognized. Return negative error code on error.
633  */
634 int chp_info_get_status(struct chp_id chpid)
635 {
636 	int rc;
637 	int bit;
638 
639 	rc = info_update();
640 	if (rc)
641 		return rc;
642 
643 	bit = info_bit_num(chpid);
644 	mutex_lock(&info_lock);
645 	if (!chp_test_bit(chp_info.recognized, bit))
646 		rc = CHP_STATUS_NOT_RECOGNIZED;
647 	else if (chp_test_bit(chp_info.configured, bit))
648 		rc = CHP_STATUS_CONFIGURED;
649 	else if (chp_test_bit(chp_info.standby, bit))
650 		rc = CHP_STATUS_STANDBY;
651 	else
652 		rc = CHP_STATUS_RESERVED;
653 	mutex_unlock(&info_lock);
654 
655 	return rc;
656 }
657 
658 /* Return configure task for chpid. */
659 static enum cfg_task_t cfg_get_task(struct chp_id chpid)
660 {
661 	return chp_cfg_task[chpid.cssid][chpid.id];
662 }
663 
664 /* Set configure task for chpid. */
665 static void cfg_set_task(struct chp_id chpid, enum cfg_task_t cfg)
666 {
667 	chp_cfg_task[chpid.cssid][chpid.id] = cfg;
668 }
669 
670 /* Fetch the first configure task. Set chpid accordingly. */
671 static enum cfg_task_t chp_cfg_fetch_task(struct chp_id *chpid)
672 {
673 	enum cfg_task_t t = cfg_none;
674 
675 	chp_id_for_each(chpid) {
676 		t = cfg_get_task(*chpid);
677 		if (t != cfg_none)
678 			break;
679 	}
680 
681 	return t;
682 }
683 
684 /* Perform one configure/deconfigure request. Reschedule work function until
685  * last request. */
686 static void cfg_func(struct work_struct *work)
687 {
688 	struct chp_id chpid;
689 	enum cfg_task_t t;
690 	int rc;
691 
692 	spin_lock(&cfg_lock);
693 	t = chp_cfg_fetch_task(&chpid);
694 	spin_unlock(&cfg_lock);
695 
696 	switch (t) {
697 	case cfg_configure:
698 		rc = sclp_chp_configure(chpid);
699 		if (rc)
700 			CIO_MSG_EVENT(2, "chp: sclp_chp_configure(%x.%02x)="
701 				      "%d\n", chpid.cssid, chpid.id, rc);
702 		else {
703 			info_expire();
704 			chsc_chp_online(chpid);
705 		}
706 		break;
707 	case cfg_deconfigure:
708 		rc = sclp_chp_deconfigure(chpid);
709 		if (rc)
710 			CIO_MSG_EVENT(2, "chp: sclp_chp_deconfigure(%x.%02x)="
711 				      "%d\n", chpid.cssid, chpid.id, rc);
712 		else {
713 			info_expire();
714 			chsc_chp_offline(chpid);
715 		}
716 		break;
717 	case cfg_none:
718 		/* Get updated information after last change. */
719 		info_update();
720 		wake_up_interruptible(&cfg_wait_queue);
721 		return;
722 	}
723 	spin_lock(&cfg_lock);
724 	if (t == cfg_get_task(chpid))
725 		cfg_set_task(chpid, cfg_none);
726 	spin_unlock(&cfg_lock);
727 	schedule_work(&cfg_work);
728 }
729 
730 /**
731  * chp_cfg_schedule - schedule chpid configuration request
732  * @chpid - channel-path ID
733  * @configure - Non-zero for configure, zero for deconfigure
734  *
735  * Schedule a channel-path configuration/deconfiguration request.
736  */
737 void chp_cfg_schedule(struct chp_id chpid, int configure)
738 {
739 	CIO_MSG_EVENT(2, "chp_cfg_sched%x.%02x=%d\n", chpid.cssid, chpid.id,
740 		      configure);
741 	spin_lock(&cfg_lock);
742 	cfg_set_task(chpid, configure ? cfg_configure : cfg_deconfigure);
743 	spin_unlock(&cfg_lock);
744 	schedule_work(&cfg_work);
745 }
746 
747 /**
748  * chp_cfg_cancel_deconfigure - cancel chpid deconfiguration request
749  * @chpid - channel-path ID
750  *
751  * Cancel an active channel-path deconfiguration request if it has not yet
752  * been performed.
753  */
754 void chp_cfg_cancel_deconfigure(struct chp_id chpid)
755 {
756 	CIO_MSG_EVENT(2, "chp_cfg_cancel:%x.%02x\n", chpid.cssid, chpid.id);
757 	spin_lock(&cfg_lock);
758 	if (cfg_get_task(chpid) == cfg_deconfigure)
759 		cfg_set_task(chpid, cfg_none);
760 	spin_unlock(&cfg_lock);
761 }
762 
763 static bool cfg_idle(void)
764 {
765 	struct chp_id chpid;
766 	enum cfg_task_t t;
767 
768 	spin_lock(&cfg_lock);
769 	t = chp_cfg_fetch_task(&chpid);
770 	spin_unlock(&cfg_lock);
771 
772 	return t == cfg_none;
773 }
774 
775 static int cfg_wait_idle(void)
776 {
777 	if (wait_event_interruptible(cfg_wait_queue, cfg_idle()))
778 		return -ERESTARTSYS;
779 	return 0;
780 }
781 
782 static int __init chp_init(void)
783 {
784 	struct chp_id chpid;
785 	int state, ret;
786 
787 	ret = crw_register_handler(CRW_RSC_CPATH, chp_process_crw);
788 	if (ret)
789 		return ret;
790 	INIT_WORK(&cfg_work, cfg_func);
791 	init_waitqueue_head(&cfg_wait_queue);
792 	if (info_update())
793 		return 0;
794 	/* Register available channel-paths. */
795 	chp_id_for_each(&chpid) {
796 		state = chp_info_get_status(chpid);
797 		if (state == CHP_STATUS_CONFIGURED ||
798 		    state == CHP_STATUS_STANDBY)
799 			chp_new(chpid);
800 	}
801 
802 	return 0;
803 }
804 
805 subsys_initcall(chp_init);
806