xref: /linux/drivers/s390/cio/chp.c (revision bdaedca74d6293b6ac643a8ebe8231b52bf1171b)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *    Copyright IBM Corp. 1999, 2010
4  *    Author(s): Cornelia Huck (cornelia.huck@de.ibm.com)
5  *		 Arnd Bergmann (arndb@de.ibm.com)
6  *		 Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
7  */
8 
9 #include <linux/bug.h>
10 #include <linux/workqueue.h>
11 #include <linux/spinlock.h>
12 #include <linux/export.h>
13 #include <linux/sched.h>
14 #include <linux/init.h>
15 #include <linux/jiffies.h>
16 #include <linux/wait.h>
17 #include <linux/mutex.h>
18 #include <linux/errno.h>
19 #include <linux/slab.h>
20 #include <asm/chpid.h>
21 #include <asm/sclp.h>
22 #include <asm/crw.h>
23 
24 #include "cio.h"
25 #include "css.h"
26 #include "ioasm.h"
27 #include "cio_debug.h"
28 #include "chp.h"
29 
30 #define to_channelpath(device) container_of(device, struct channel_path, dev)
31 #define CHP_INFO_UPDATE_INTERVAL	1*HZ
32 
33 enum cfg_task_t {
34 	cfg_none,
35 	cfg_configure,
36 	cfg_deconfigure
37 };
38 
39 /* Map for pending configure tasks. */
40 static enum cfg_task_t chp_cfg_task[__MAX_CSSID + 1][__MAX_CHPID + 1];
41 static DEFINE_SPINLOCK(cfg_lock);
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47 /* Time after which channel-path status may be outdated.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 static struct work_struct cfg_work;
51 
52 /* Wait queue for configure completion events. */
53 static DECLARE_WAIT_QUEUE_HEAD(cfg_wait_queue);
54 
55 /* Set vary state for given chpid. */
56 static void set_chp_logically_online(struct chp_id chpid, int onoff)
57 {
58 	chpid_to_chp(chpid)->state = onoff;
59 }
60 
61 /* On success return 0 if channel-path is varied offline, 1 if it is varied
62  * online. Return -ENODEV if channel-path is not registered. */
63 int chp_get_status(struct chp_id chpid)
64 {
65 	return (chpid_to_chp(chpid) ? chpid_to_chp(chpid)->state : -ENODEV);
66 }
67 
68 /**
69  * chp_get_sch_opm - return opm for subchannel
70  * @sch: subchannel
71  *
72  * Calculate and return the operational path mask (opm) based on the chpids
73  * used by the subchannel and the status of the associated channel-paths.
74  */
75 u8 chp_get_sch_opm(struct subchannel *sch)
76 {
77 	struct chp_id chpid;
78 	int opm;
79 	int i;
80 
81 	opm = 0;
82 	chp_id_init(&chpid);
83 	for (i = 0; i < 8; i++) {
84 		opm <<= 1;
85 		chpid.id = sch->schib.pmcw.chpid[i];
86 		if (chp_get_status(chpid) != 0)
87 			opm |= 1;
88 	}
89 	return opm;
90 }
91 EXPORT_SYMBOL_GPL(chp_get_sch_opm);
92 
93 /**
94  * chp_is_registered - check if a channel-path is registered
95  * @chpid: channel-path ID
96  *
97  * Return non-zero if a channel-path with the given chpid is registered,
98  * zero otherwise.
99  */
100 int chp_is_registered(struct chp_id chpid)
101 {
102 	return chpid_to_chp(chpid) != NULL;
103 }
104 
105 /*
106  * Function: s390_vary_chpid
107  * Varies the specified chpid online or offline
108  */
109 static int s390_vary_chpid(struct chp_id chpid, int on)
110 {
111 	char dbf_text[15];
112 	int status;
113 
114 	sprintf(dbf_text, on?"varyon%x.%02x":"varyoff%x.%02x", chpid.cssid,
115 		chpid.id);
116 	CIO_TRACE_EVENT(2, dbf_text);
117 
118 	status = chp_get_status(chpid);
119 	if (!on && !status)
120 		return 0;
121 
122 	set_chp_logically_online(chpid, on);
123 	chsc_chp_vary(chpid, on);
124 	return 0;
125 }
126 
127 /*
128  * Channel measurement related functions
129  */
130 static ssize_t chp_measurement_chars_read(struct file *filp,
131 					  struct kobject *kobj,
132 					  struct bin_attribute *bin_attr,
133 					  char *buf, loff_t off, size_t count)
134 {
135 	struct channel_path *chp;
136 	struct device *device;
137 
138 	device = kobj_to_dev(kobj);
139 	chp = to_channelpath(device);
140 	if (chp->cmg == -1)
141 		return 0;
142 
143 	return memory_read_from_buffer(buf, count, &off, &chp->cmg_chars,
144 				       sizeof(chp->cmg_chars));
145 }
146 
147 static const struct bin_attribute chp_measurement_chars_attr = {
148 	.attr = {
149 		.name = "measurement_chars",
150 		.mode = S_IRUSR,
151 	},
152 	.size = sizeof(struct cmg_chars),
153 	.read = chp_measurement_chars_read,
154 };
155 
156 static void chp_measurement_copy_block(struct cmg_entry *buf,
157 				       struct channel_subsystem *css,
158 				       struct chp_id chpid)
159 {
160 	void *area;
161 	struct cmg_entry *entry, reference_buf;
162 	int idx;
163 
164 	if (chpid.id < 128) {
165 		area = css->cub_addr1;
166 		idx = chpid.id;
167 	} else {
168 		area = css->cub_addr2;
169 		idx = chpid.id - 128;
170 	}
171 	entry = area + (idx * sizeof(struct cmg_entry));
172 	do {
173 		memcpy(buf, entry, sizeof(*entry));
174 		memcpy(&reference_buf, entry, sizeof(*entry));
175 	} while (reference_buf.values[0] != buf->values[0]);
176 }
177 
178 static ssize_t chp_measurement_read(struct file *filp, struct kobject *kobj,
179 				    struct bin_attribute *bin_attr,
180 				    char *buf, loff_t off, size_t count)
181 {
182 	struct channel_path *chp;
183 	struct channel_subsystem *css;
184 	struct device *device;
185 	unsigned int size;
186 
187 	device = kobj_to_dev(kobj);
188 	chp = to_channelpath(device);
189 	css = to_css(chp->dev.parent);
190 
191 	size = sizeof(struct cmg_entry);
192 
193 	/* Only allow single reads. */
194 	if (off || count < size)
195 		return 0;
196 	chp_measurement_copy_block((struct cmg_entry *)buf, css, chp->chpid);
197 	count = size;
198 	return count;
199 }
200 
201 static const struct bin_attribute chp_measurement_attr = {
202 	.attr = {
203 		.name = "measurement",
204 		.mode = S_IRUSR,
205 	},
206 	.size = sizeof(struct cmg_entry),
207 	.read = chp_measurement_read,
208 };
209 
210 void chp_remove_cmg_attr(struct channel_path *chp)
211 {
212 	device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
213 	device_remove_bin_file(&chp->dev, &chp_measurement_attr);
214 }
215 
216 int chp_add_cmg_attr(struct channel_path *chp)
217 {
218 	int ret;
219 
220 	ret = device_create_bin_file(&chp->dev, &chp_measurement_chars_attr);
221 	if (ret)
222 		return ret;
223 	ret = device_create_bin_file(&chp->dev, &chp_measurement_attr);
224 	if (ret)
225 		device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
226 	return ret;
227 }
228 
229 /*
230  * Files for the channel path entries.
231  */
232 static ssize_t chp_status_show(struct device *dev,
233 			       struct device_attribute *attr, char *buf)
234 {
235 	struct channel_path *chp = to_channelpath(dev);
236 	int status;
237 
238 	mutex_lock(&chp->lock);
239 	status = chp->state;
240 	mutex_unlock(&chp->lock);
241 
242 	return status ? sprintf(buf, "online\n") : sprintf(buf, "offline\n");
243 }
244 
245 static ssize_t chp_status_write(struct device *dev,
246 				struct device_attribute *attr,
247 				const char *buf, size_t count)
248 {
249 	struct channel_path *cp = to_channelpath(dev);
250 	char cmd[10];
251 	int num_args;
252 	int error;
253 
254 	num_args = sscanf(buf, "%5s", cmd);
255 	if (!num_args)
256 		return count;
257 
258 	if (!strncasecmp(cmd, "on", 2) || !strcmp(cmd, "1")) {
259 		mutex_lock(&cp->lock);
260 		error = s390_vary_chpid(cp->chpid, 1);
261 		mutex_unlock(&cp->lock);
262 	} else if (!strncasecmp(cmd, "off", 3) || !strcmp(cmd, "0")) {
263 		mutex_lock(&cp->lock);
264 		error = s390_vary_chpid(cp->chpid, 0);
265 		mutex_unlock(&cp->lock);
266 	} else
267 		error = -EINVAL;
268 
269 	return error < 0 ? error : count;
270 }
271 
272 static DEVICE_ATTR(status, 0644, chp_status_show, chp_status_write);
273 
274 static ssize_t chp_configure_show(struct device *dev,
275 				  struct device_attribute *attr, char *buf)
276 {
277 	struct channel_path *cp;
278 	int status;
279 
280 	cp = to_channelpath(dev);
281 	status = chp_info_get_status(cp->chpid);
282 	if (status < 0)
283 		return status;
284 
285 	return snprintf(buf, PAGE_SIZE, "%d\n", status);
286 }
287 
288 static int cfg_wait_idle(void);
289 
290 static ssize_t chp_configure_write(struct device *dev,
291 				   struct device_attribute *attr,
292 				   const char *buf, size_t count)
293 {
294 	struct channel_path *cp;
295 	int val;
296 	char delim;
297 
298 	if (sscanf(buf, "%d %c", &val, &delim) != 1)
299 		return -EINVAL;
300 	if (val != 0 && val != 1)
301 		return -EINVAL;
302 	cp = to_channelpath(dev);
303 	chp_cfg_schedule(cp->chpid, val);
304 	cfg_wait_idle();
305 
306 	return count;
307 }
308 
309 static DEVICE_ATTR(configure, 0644, chp_configure_show, chp_configure_write);
310 
311 static ssize_t chp_type_show(struct device *dev, struct device_attribute *attr,
312 			     char *buf)
313 {
314 	struct channel_path *chp = to_channelpath(dev);
315 	u8 type;
316 
317 	mutex_lock(&chp->lock);
318 	type = chp->desc.desc;
319 	mutex_unlock(&chp->lock);
320 	return sprintf(buf, "%x\n", type);
321 }
322 
323 static DEVICE_ATTR(type, 0444, chp_type_show, NULL);
324 
325 static ssize_t chp_cmg_show(struct device *dev, struct device_attribute *attr,
326 			    char *buf)
327 {
328 	struct channel_path *chp = to_channelpath(dev);
329 
330 	if (!chp)
331 		return 0;
332 	if (chp->cmg == -1) /* channel measurements not available */
333 		return sprintf(buf, "unknown\n");
334 	return sprintf(buf, "%x\n", chp->cmg);
335 }
336 
337 static DEVICE_ATTR(cmg, 0444, chp_cmg_show, NULL);
338 
339 static ssize_t chp_shared_show(struct device *dev,
340 			       struct device_attribute *attr, char *buf)
341 {
342 	struct channel_path *chp = to_channelpath(dev);
343 
344 	if (!chp)
345 		return 0;
346 	if (chp->shared == -1) /* channel measurements not available */
347 		return sprintf(buf, "unknown\n");
348 	return sprintf(buf, "%x\n", chp->shared);
349 }
350 
351 static DEVICE_ATTR(shared, 0444, chp_shared_show, NULL);
352 
353 static ssize_t chp_chid_show(struct device *dev, struct device_attribute *attr,
354 			     char *buf)
355 {
356 	struct channel_path *chp = to_channelpath(dev);
357 	ssize_t rc;
358 
359 	mutex_lock(&chp->lock);
360 	if (chp->desc_fmt1.flags & 0x10)
361 		rc = sprintf(buf, "%04x\n", chp->desc_fmt1.chid);
362 	else
363 		rc = 0;
364 	mutex_unlock(&chp->lock);
365 
366 	return rc;
367 }
368 static DEVICE_ATTR(chid, 0444, chp_chid_show, NULL);
369 
370 static ssize_t chp_chid_external_show(struct device *dev,
371 				      struct device_attribute *attr, char *buf)
372 {
373 	struct channel_path *chp = to_channelpath(dev);
374 	ssize_t rc;
375 
376 	mutex_lock(&chp->lock);
377 	if (chp->desc_fmt1.flags & 0x10)
378 		rc = sprintf(buf, "%x\n", chp->desc_fmt1.flags & 0x8 ? 1 : 0);
379 	else
380 		rc = 0;
381 	mutex_unlock(&chp->lock);
382 
383 	return rc;
384 }
385 static DEVICE_ATTR(chid_external, 0444, chp_chid_external_show, NULL);
386 
387 static ssize_t chp_esc_show(struct device *dev,
388 			    struct device_attribute *attr, char *buf)
389 {
390 	struct channel_path *chp = to_channelpath(dev);
391 	ssize_t rc;
392 
393 	mutex_lock(&chp->lock);
394 	rc = sprintf(buf, "%x\n", chp->desc_fmt1.esc);
395 	mutex_unlock(&chp->lock);
396 
397 	return rc;
398 }
399 static DEVICE_ATTR(esc, 0444, chp_esc_show, NULL);
400 
401 static ssize_t util_string_read(struct file *filp, struct kobject *kobj,
402 				struct bin_attribute *attr, char *buf,
403 				loff_t off, size_t count)
404 {
405 	struct channel_path *chp = to_channelpath(kobj_to_dev(kobj));
406 	ssize_t rc;
407 
408 	mutex_lock(&chp->lock);
409 	rc = memory_read_from_buffer(buf, count, &off, chp->desc_fmt3.util_str,
410 				     sizeof(chp->desc_fmt3.util_str));
411 	mutex_unlock(&chp->lock);
412 
413 	return rc;
414 }
415 static BIN_ATTR_RO(util_string,
416 		   sizeof(((struct channel_path_desc_fmt3 *)0)->util_str));
417 
418 static struct bin_attribute *chp_bin_attrs[] = {
419 	&bin_attr_util_string,
420 	NULL,
421 };
422 
423 static struct attribute *chp_attrs[] = {
424 	&dev_attr_status.attr,
425 	&dev_attr_configure.attr,
426 	&dev_attr_type.attr,
427 	&dev_attr_cmg.attr,
428 	&dev_attr_shared.attr,
429 	&dev_attr_chid.attr,
430 	&dev_attr_chid_external.attr,
431 	&dev_attr_esc.attr,
432 	NULL,
433 };
434 static struct attribute_group chp_attr_group = {
435 	.attrs = chp_attrs,
436 	.bin_attrs = chp_bin_attrs,
437 };
438 static const struct attribute_group *chp_attr_groups[] = {
439 	&chp_attr_group,
440 	NULL,
441 };
442 
443 static void chp_release(struct device *dev)
444 {
445 	struct channel_path *cp;
446 
447 	cp = to_channelpath(dev);
448 	kfree(cp);
449 }
450 
451 /**
452  * chp_update_desc - update channel-path description
453  * @chp: channel-path
454  *
455  * Update the channel-path description of the specified channel-path
456  * including channel measurement related information.
457  * Return zero on success, non-zero otherwise.
458  */
459 int chp_update_desc(struct channel_path *chp)
460 {
461 	int rc;
462 
463 	rc = chsc_determine_fmt0_channel_path_desc(chp->chpid, &chp->desc);
464 	if (rc)
465 		return rc;
466 
467 	/*
468 	 * Fetching the following data is optional. Not all machines or
469 	 * hypervisors implement the required chsc commands.
470 	 */
471 	chsc_determine_fmt1_channel_path_desc(chp->chpid, &chp->desc_fmt1);
472 	chsc_determine_fmt3_channel_path_desc(chp->chpid, &chp->desc_fmt3);
473 	chsc_get_channel_measurement_chars(chp);
474 
475 	return 0;
476 }
477 
478 /**
479  * chp_new - register a new channel-path
480  * @chpid: channel-path ID
481  *
482  * Create and register data structure representing new channel-path. Return
483  * zero on success, non-zero otherwise.
484  */
485 int chp_new(struct chp_id chpid)
486 {
487 	struct channel_subsystem *css = css_by_id(chpid.cssid);
488 	struct channel_path *chp;
489 	int ret = 0;
490 
491 	mutex_lock(&css->mutex);
492 	if (chp_is_registered(chpid))
493 		goto out;
494 
495 	chp = kzalloc(sizeof(struct channel_path), GFP_KERNEL);
496 	if (!chp) {
497 		ret = -ENOMEM;
498 		goto out;
499 	}
500 	/* fill in status, etc. */
501 	chp->chpid = chpid;
502 	chp->state = 1;
503 	chp->dev.parent = &css->device;
504 	chp->dev.groups = chp_attr_groups;
505 	chp->dev.release = chp_release;
506 	mutex_init(&chp->lock);
507 
508 	/* Obtain channel path description and fill it in. */
509 	ret = chp_update_desc(chp);
510 	if (ret)
511 		goto out_free;
512 	if ((chp->desc.flags & 0x80) == 0) {
513 		ret = -ENODEV;
514 		goto out_free;
515 	}
516 	dev_set_name(&chp->dev, "chp%x.%02x", chpid.cssid, chpid.id);
517 
518 	/* make it known to the system */
519 	ret = device_register(&chp->dev);
520 	if (ret) {
521 		CIO_MSG_EVENT(0, "Could not register chp%x.%02x: %d\n",
522 			      chpid.cssid, chpid.id, ret);
523 		put_device(&chp->dev);
524 		goto out;
525 	}
526 
527 	if (css->cm_enabled) {
528 		ret = chp_add_cmg_attr(chp);
529 		if (ret) {
530 			device_unregister(&chp->dev);
531 			goto out;
532 		}
533 	}
534 	css->chps[chpid.id] = chp;
535 	goto out;
536 out_free:
537 	kfree(chp);
538 out:
539 	mutex_unlock(&css->mutex);
540 	return ret;
541 }
542 
543 /**
544  * chp_get_chp_desc - return newly allocated channel-path description
545  * @chpid: channel-path ID
546  *
547  * On success return a newly allocated copy of the channel-path description
548  * data associated with the given channel-path ID. Return %NULL on error.
549  */
550 struct channel_path_desc_fmt0 *chp_get_chp_desc(struct chp_id chpid)
551 {
552 	struct channel_path *chp;
553 	struct channel_path_desc_fmt0 *desc;
554 
555 	chp = chpid_to_chp(chpid);
556 	if (!chp)
557 		return NULL;
558 	desc = kmalloc(sizeof(*desc), GFP_KERNEL);
559 	if (!desc)
560 		return NULL;
561 
562 	mutex_lock(&chp->lock);
563 	memcpy(desc, &chp->desc, sizeof(*desc));
564 	mutex_unlock(&chp->lock);
565 	return desc;
566 }
567 
568 /**
569  * chp_process_crw - process channel-path status change
570  * @crw0: channel report-word to handler
571  * @crw1: second channel-report word (always NULL)
572  * @overflow: crw overflow indication
573  *
574  * Handle channel-report-words indicating that the status of a channel-path
575  * has changed.
576  */
577 static void chp_process_crw(struct crw *crw0, struct crw *crw1,
578 			    int overflow)
579 {
580 	struct chp_id chpid;
581 
582 	if (overflow) {
583 		css_schedule_eval_all();
584 		return;
585 	}
586 	CIO_CRW_EVENT(2, "CRW reports slct=%d, oflw=%d, "
587 		      "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
588 		      crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
589 		      crw0->erc, crw0->rsid);
590 	/*
591 	 * Check for solicited machine checks. These are
592 	 * created by reset channel path and need not be
593 	 * handled here.
594 	 */
595 	if (crw0->slct) {
596 		CIO_CRW_EVENT(2, "solicited machine check for "
597 			      "channel path %02X\n", crw0->rsid);
598 		return;
599 	}
600 	chp_id_init(&chpid);
601 	chpid.id = crw0->rsid;
602 	switch (crw0->erc) {
603 	case CRW_ERC_IPARM: /* Path has come. */
604 	case CRW_ERC_INIT:
605 		chp_new(chpid);
606 		chsc_chp_online(chpid);
607 		break;
608 	case CRW_ERC_PERRI: /* Path has gone. */
609 	case CRW_ERC_PERRN:
610 		chsc_chp_offline(chpid);
611 		break;
612 	default:
613 		CIO_CRW_EVENT(2, "Don't know how to handle erc=%x\n",
614 			      crw0->erc);
615 	}
616 }
617 
618 int chp_ssd_get_mask(struct chsc_ssd_info *ssd, struct chp_link *link)
619 {
620 	int i;
621 	int mask;
622 
623 	for (i = 0; i < 8; i++) {
624 		mask = 0x80 >> i;
625 		if (!(ssd->path_mask & mask))
626 			continue;
627 		if (!chp_id_is_equal(&ssd->chpid[i], &link->chpid))
628 			continue;
629 		if ((ssd->fla_valid_mask & mask) &&
630 		    ((ssd->fla[i] & link->fla_mask) != link->fla))
631 			continue;
632 		return mask;
633 	}
634 	return 0;
635 }
636 EXPORT_SYMBOL_GPL(chp_ssd_get_mask);
637 
638 static inline int info_bit_num(struct chp_id id)
639 {
640 	return id.id + id.cssid * (__MAX_CHPID + 1);
641 }
642 
643 /* Force chp_info refresh on next call to info_validate(). */
644 static void info_expire(void)
645 {
646 	mutex_lock(&info_lock);
647 	chp_info_expires = jiffies - 1;
648 	mutex_unlock(&info_lock);
649 }
650 
651 /* Ensure that chp_info is up-to-date. */
652 static int info_update(void)
653 {
654 	int rc;
655 
656 	mutex_lock(&info_lock);
657 	rc = 0;
658 	if (time_after(jiffies, chp_info_expires)) {
659 		/* Data is too old, update. */
660 		rc = sclp_chp_read_info(&chp_info);
661 		chp_info_expires = jiffies + CHP_INFO_UPDATE_INTERVAL ;
662 	}
663 	mutex_unlock(&info_lock);
664 
665 	return rc;
666 }
667 
668 /**
669  * chp_info_get_status - retrieve configure status of a channel-path
670  * @chpid: channel-path ID
671  *
672  * On success, return 0 for standby, 1 for configured, 2 for reserved,
673  * 3 for not recognized. Return negative error code on error.
674  */
675 int chp_info_get_status(struct chp_id chpid)
676 {
677 	int rc;
678 	int bit;
679 
680 	rc = info_update();
681 	if (rc)
682 		return rc;
683 
684 	bit = info_bit_num(chpid);
685 	mutex_lock(&info_lock);
686 	if (!chp_test_bit(chp_info.recognized, bit))
687 		rc = CHP_STATUS_NOT_RECOGNIZED;
688 	else if (chp_test_bit(chp_info.configured, bit))
689 		rc = CHP_STATUS_CONFIGURED;
690 	else if (chp_test_bit(chp_info.standby, bit))
691 		rc = CHP_STATUS_STANDBY;
692 	else
693 		rc = CHP_STATUS_RESERVED;
694 	mutex_unlock(&info_lock);
695 
696 	return rc;
697 }
698 
699 /* Return configure task for chpid. */
700 static enum cfg_task_t cfg_get_task(struct chp_id chpid)
701 {
702 	return chp_cfg_task[chpid.cssid][chpid.id];
703 }
704 
705 /* Set configure task for chpid. */
706 static void cfg_set_task(struct chp_id chpid, enum cfg_task_t cfg)
707 {
708 	chp_cfg_task[chpid.cssid][chpid.id] = cfg;
709 }
710 
711 /* Fetch the first configure task. Set chpid accordingly. */
712 static enum cfg_task_t chp_cfg_fetch_task(struct chp_id *chpid)
713 {
714 	enum cfg_task_t t = cfg_none;
715 
716 	chp_id_for_each(chpid) {
717 		t = cfg_get_task(*chpid);
718 		if (t != cfg_none)
719 			break;
720 	}
721 
722 	return t;
723 }
724 
725 /* Perform one configure/deconfigure request. Reschedule work function until
726  * last request. */
727 static void cfg_func(struct work_struct *work)
728 {
729 	struct chp_id chpid;
730 	enum cfg_task_t t;
731 	int rc;
732 
733 	spin_lock(&cfg_lock);
734 	t = chp_cfg_fetch_task(&chpid);
735 	spin_unlock(&cfg_lock);
736 
737 	switch (t) {
738 	case cfg_configure:
739 		rc = sclp_chp_configure(chpid);
740 		if (rc)
741 			CIO_MSG_EVENT(2, "chp: sclp_chp_configure(%x.%02x)="
742 				      "%d\n", chpid.cssid, chpid.id, rc);
743 		else {
744 			info_expire();
745 			chsc_chp_online(chpid);
746 		}
747 		break;
748 	case cfg_deconfigure:
749 		rc = sclp_chp_deconfigure(chpid);
750 		if (rc)
751 			CIO_MSG_EVENT(2, "chp: sclp_chp_deconfigure(%x.%02x)="
752 				      "%d\n", chpid.cssid, chpid.id, rc);
753 		else {
754 			info_expire();
755 			chsc_chp_offline(chpid);
756 		}
757 		break;
758 	case cfg_none:
759 		/* Get updated information after last change. */
760 		info_update();
761 		wake_up_interruptible(&cfg_wait_queue);
762 		return;
763 	}
764 	spin_lock(&cfg_lock);
765 	if (t == cfg_get_task(chpid))
766 		cfg_set_task(chpid, cfg_none);
767 	spin_unlock(&cfg_lock);
768 	schedule_work(&cfg_work);
769 }
770 
771 /**
772  * chp_cfg_schedule - schedule chpid configuration request
773  * @chpid: channel-path ID
774  * @configure: Non-zero for configure, zero for deconfigure
775  *
776  * Schedule a channel-path configuration/deconfiguration request.
777  */
778 void chp_cfg_schedule(struct chp_id chpid, int configure)
779 {
780 	CIO_MSG_EVENT(2, "chp_cfg_sched%x.%02x=%d\n", chpid.cssid, chpid.id,
781 		      configure);
782 	spin_lock(&cfg_lock);
783 	cfg_set_task(chpid, configure ? cfg_configure : cfg_deconfigure);
784 	spin_unlock(&cfg_lock);
785 	schedule_work(&cfg_work);
786 }
787 
788 /**
789  * chp_cfg_cancel_deconfigure - cancel chpid deconfiguration request
790  * @chpid: channel-path ID
791  *
792  * Cancel an active channel-path deconfiguration request if it has not yet
793  * been performed.
794  */
795 void chp_cfg_cancel_deconfigure(struct chp_id chpid)
796 {
797 	CIO_MSG_EVENT(2, "chp_cfg_cancel:%x.%02x\n", chpid.cssid, chpid.id);
798 	spin_lock(&cfg_lock);
799 	if (cfg_get_task(chpid) == cfg_deconfigure)
800 		cfg_set_task(chpid, cfg_none);
801 	spin_unlock(&cfg_lock);
802 }
803 
804 static bool cfg_idle(void)
805 {
806 	struct chp_id chpid;
807 	enum cfg_task_t t;
808 
809 	spin_lock(&cfg_lock);
810 	t = chp_cfg_fetch_task(&chpid);
811 	spin_unlock(&cfg_lock);
812 
813 	return t == cfg_none;
814 }
815 
816 static int cfg_wait_idle(void)
817 {
818 	if (wait_event_interruptible(cfg_wait_queue, cfg_idle()))
819 		return -ERESTARTSYS;
820 	return 0;
821 }
822 
823 static int __init chp_init(void)
824 {
825 	struct chp_id chpid;
826 	int state, ret;
827 
828 	ret = crw_register_handler(CRW_RSC_CPATH, chp_process_crw);
829 	if (ret)
830 		return ret;
831 	INIT_WORK(&cfg_work, cfg_func);
832 	if (info_update())
833 		return 0;
834 	/* Register available channel-paths. */
835 	chp_id_for_each(&chpid) {
836 		state = chp_info_get_status(chpid);
837 		if (state == CHP_STATUS_CONFIGURED ||
838 		    state == CHP_STATUS_STANDBY)
839 			chp_new(chpid);
840 	}
841 
842 	return 0;
843 }
844 
845 subsys_initcall(chp_init);
846