xref: /linux/drivers/s390/cio/chp.c (revision 7fc2cd2e4b398c57c9cf961cfea05eadbf34c05c)
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47 /* Time after which channel-path status may be outdated.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 	scnprintf(dbf_text, sizeof(dbf_text),
115 		  on ? "varyon%x.%02x" : "varyoff%x.%02x",
116 		  chpid.cssid, chpid.id);
117 	CIO_TRACE_EVENT(2, dbf_text);
118 
119 	status = chp_get_status(chpid);
120 	if (!on && !status)
121 		return 0;
122 
123 	set_chp_logically_online(chpid, on);
124 	chsc_chp_vary(chpid, on);
125 	return 0;
126 }
127 
128 /*
129  * Channel measurement related functions
130  */
131 static ssize_t measurement_chars_read(struct file *filp, struct kobject *kobj,
132 				      const 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 static const BIN_ATTR_ADMIN_RO(measurement_chars, sizeof(struct cmg_chars));
147 
148 static ssize_t measurement_chars_full_read(struct file *filp,
149 					   struct kobject *kobj,
150 					   const struct bin_attribute *bin_attr,
151 					   char *buf, loff_t off, size_t count)
152 {
153 	struct channel_path *chp = to_channelpath(kobj_to_dev(kobj));
154 
155 	return memory_read_from_buffer(buf, count, &off, &chp->cmcb,
156 				       sizeof(chp->cmcb));
157 }
158 static BIN_ATTR_ADMIN_RO(measurement_chars_full, sizeof(struct cmg_cmcb));
159 
160 static ssize_t chp_measurement_copy_block(void *buf, loff_t off, size_t count,
161 					  struct kobject *kobj, bool extended)
162 {
163 	struct channel_path *chp;
164 	struct channel_subsystem *css;
165 	struct device *device;
166 	unsigned int size;
167 	void *area, *entry;
168 	int id, idx;
169 
170 	device = kobj_to_dev(kobj);
171 	chp = to_channelpath(device);
172 	css = to_css(chp->dev.parent);
173 	id = chp->chpid.id;
174 
175 	if (extended) {
176 		/* Check if extended measurement data is available. */
177 		if (!chp->extended)
178 			return 0;
179 
180 		size = sizeof(struct cmg_ext_entry);
181 		area = css->ecub[id / CSS_ECUES_PER_PAGE];
182 		idx = id % CSS_ECUES_PER_PAGE;
183 	} else {
184 		size = sizeof(struct cmg_entry);
185 		area = css->cub[id / CSS_CUES_PER_PAGE];
186 		idx = id % CSS_CUES_PER_PAGE;
187 	}
188 	entry = area + (idx * size);
189 
190 	/* Only allow single reads. */
191 	if (off || count < size)
192 		return 0;
193 
194 	memcpy(buf, entry, size);
195 
196 	return size;
197 }
198 
199 static ssize_t measurement_read(struct file *filp, struct kobject *kobj,
200 				const struct bin_attribute *bin_attr,
201 				char *buf, loff_t off, size_t count)
202 {
203 	return chp_measurement_copy_block(buf, off, count, kobj, false);
204 }
205 static const BIN_ATTR_ADMIN_RO(measurement, sizeof(struct cmg_entry));
206 
207 static ssize_t ext_measurement_read(struct file *filp, struct kobject *kobj,
208 				    const struct bin_attribute *bin_attr,
209 				    char *buf, loff_t off, size_t count)
210 {
211 	return chp_measurement_copy_block(buf, off, count, kobj, true);
212 }
213 static const BIN_ATTR_ADMIN_RO(ext_measurement, sizeof(struct cmg_ext_entry));
214 
215 static const struct bin_attribute *measurement_attrs[] = {
216 	&bin_attr_measurement_chars,
217 	&bin_attr_measurement_chars_full,
218 	&bin_attr_measurement,
219 	&bin_attr_ext_measurement,
220 	NULL,
221 };
222 BIN_ATTRIBUTE_GROUPS(measurement);
223 
224 void chp_remove_cmg_attr(struct channel_path *chp)
225 {
226 	device_remove_groups(&chp->dev, measurement_groups);
227 }
228 
229 int chp_add_cmg_attr(struct channel_path *chp)
230 {
231 	return device_add_groups(&chp->dev, measurement_groups);
232 }
233 
234 /*
235  * Files for the channel path entries.
236  */
237 static ssize_t chp_status_show(struct device *dev,
238 			       struct device_attribute *attr, char *buf)
239 {
240 	struct channel_path *chp = to_channelpath(dev);
241 	int status;
242 
243 	mutex_lock(&chp->lock);
244 	status = chp->state;
245 	mutex_unlock(&chp->lock);
246 
247 	return status ? sysfs_emit(buf, "online\n") : sysfs_emit(buf, "offline\n");
248 }
249 
250 static ssize_t chp_status_write(struct device *dev,
251 				struct device_attribute *attr,
252 				const char *buf, size_t count)
253 {
254 	struct channel_path *cp = to_channelpath(dev);
255 	char cmd[10];
256 	int num_args;
257 	int error;
258 
259 	num_args = sscanf(buf, "%5s", cmd);
260 	if (!num_args)
261 		return count;
262 
263 	/* Wait until previous actions have settled. */
264 	css_wait_for_slow_path();
265 
266 	if (!strncasecmp(cmd, "on", 2) || !strcmp(cmd, "1")) {
267 		mutex_lock(&cp->lock);
268 		error = s390_vary_chpid(cp->chpid, 1);
269 		mutex_unlock(&cp->lock);
270 	} else if (!strncasecmp(cmd, "off", 3) || !strcmp(cmd, "0")) {
271 		mutex_lock(&cp->lock);
272 		error = s390_vary_chpid(cp->chpid, 0);
273 		mutex_unlock(&cp->lock);
274 	} else
275 		error = -EINVAL;
276 
277 	return error < 0 ? error : count;
278 }
279 
280 static DEVICE_ATTR(status, 0644, chp_status_show, chp_status_write);
281 
282 static ssize_t chp_configure_show(struct device *dev,
283 				  struct device_attribute *attr, char *buf)
284 {
285 	struct channel_path *cp;
286 	int status;
287 
288 	cp = to_channelpath(dev);
289 	status = chp_info_get_status(cp->chpid);
290 	if (status < 0)
291 		return status;
292 
293 	return sysfs_emit(buf, "%d\n", status);
294 }
295 
296 static int cfg_wait_idle(void);
297 
298 static ssize_t chp_configure_write(struct device *dev,
299 				   struct device_attribute *attr,
300 				   const char *buf, size_t count)
301 {
302 	struct channel_path *cp;
303 	int val;
304 	char delim;
305 
306 	if (sscanf(buf, "%d %c", &val, &delim) != 1)
307 		return -EINVAL;
308 	if (val != 0 && val != 1)
309 		return -EINVAL;
310 	cp = to_channelpath(dev);
311 	chp_cfg_schedule(cp->chpid, val);
312 	cfg_wait_idle();
313 
314 	return count;
315 }
316 
317 static DEVICE_ATTR(configure, 0644, chp_configure_show, chp_configure_write);
318 
319 static ssize_t chp_type_show(struct device *dev, struct device_attribute *attr,
320 			     char *buf)
321 {
322 	struct channel_path *chp = to_channelpath(dev);
323 	u8 type;
324 
325 	mutex_lock(&chp->lock);
326 	type = chp->desc.desc;
327 	mutex_unlock(&chp->lock);
328 	return sysfs_emit(buf, "%x\n", type);
329 }
330 
331 static DEVICE_ATTR(type, 0444, chp_type_show, NULL);
332 
333 static ssize_t chp_cmg_show(struct device *dev, struct device_attribute *attr,
334 			    char *buf)
335 {
336 	struct channel_path *chp = to_channelpath(dev);
337 
338 	if (!chp)
339 		return 0;
340 	if (chp->cmg == -1) /* channel measurements not available */
341 		return sysfs_emit(buf, "unknown\n");
342 	return sysfs_emit(buf, "%d\n", chp->cmg);
343 }
344 
345 static DEVICE_ATTR(cmg, 0444, chp_cmg_show, NULL);
346 
347 static ssize_t chp_shared_show(struct device *dev,
348 			       struct device_attribute *attr, char *buf)
349 {
350 	struct channel_path *chp = to_channelpath(dev);
351 
352 	if (!chp)
353 		return 0;
354 	if (chp->shared == -1) /* channel measurements not available */
355 		return sysfs_emit(buf, "unknown\n");
356 	return sysfs_emit(buf, "%x\n", chp->shared);
357 }
358 
359 static DEVICE_ATTR(shared, 0444, chp_shared_show, NULL);
360 
361 static ssize_t chp_chid_show(struct device *dev, struct device_attribute *attr,
362 			     char *buf)
363 {
364 	struct channel_path *chp = to_channelpath(dev);
365 	ssize_t rc;
366 
367 	mutex_lock(&chp->lock);
368 	if (chp->desc_fmt1.flags & 0x10)
369 		rc = sysfs_emit(buf, "%04x\n", chp->desc_fmt1.chid);
370 	else
371 		rc = 0;
372 	mutex_unlock(&chp->lock);
373 
374 	return rc;
375 }
376 static DEVICE_ATTR(chid, 0444, chp_chid_show, NULL);
377 
378 static ssize_t chp_chid_external_show(struct device *dev,
379 				      struct device_attribute *attr, char *buf)
380 {
381 	struct channel_path *chp = to_channelpath(dev);
382 	ssize_t rc;
383 
384 	mutex_lock(&chp->lock);
385 	if (chp->desc_fmt1.flags & 0x10)
386 		rc = sysfs_emit(buf, "%x\n", chp->desc_fmt1.flags & 0x8 ? 1 : 0);
387 	else
388 		rc = 0;
389 	mutex_unlock(&chp->lock);
390 
391 	return rc;
392 }
393 static DEVICE_ATTR(chid_external, 0444, chp_chid_external_show, NULL);
394 
395 static ssize_t chp_esc_show(struct device *dev,
396 			    struct device_attribute *attr, char *buf)
397 {
398 	struct channel_path *chp = to_channelpath(dev);
399 	ssize_t rc;
400 
401 	mutex_lock(&chp->lock);
402 	rc = sysfs_emit(buf, "%x\n", chp->desc_fmt1.esc);
403 	mutex_unlock(&chp->lock);
404 
405 	return rc;
406 }
407 static DEVICE_ATTR(esc, 0444, chp_esc_show, NULL);
408 
409 static char apply_max_suffix(unsigned long *value, unsigned long base)
410 {
411 	static char suffixes[] = { 0, 'K', 'M', 'G', 'T' };
412 	int i;
413 
414 	for (i = 0; i < ARRAY_SIZE(suffixes) - 1; i++) {
415 		if (*value < base || *value % base != 0)
416 			break;
417 		*value /= base;
418 	}
419 
420 	return suffixes[i];
421 }
422 
423 static ssize_t speed_bps_show(struct device *dev,
424 			      struct device_attribute *attr, char *buf)
425 {
426 	struct channel_path *chp = to_channelpath(dev);
427 	unsigned long speed = chp->speed;
428 	char suffix;
429 
430 	suffix = apply_max_suffix(&speed, 1000);
431 
432 	return suffix ? sysfs_emit(buf, "%lu%c\n", speed, suffix) :
433 			sysfs_emit(buf, "%lu\n", speed);
434 }
435 
436 static DEVICE_ATTR_RO(speed_bps);
437 
438 static ssize_t util_string_read(struct file *filp, struct kobject *kobj,
439 				const struct bin_attribute *attr, char *buf,
440 				loff_t off, size_t count)
441 {
442 	struct channel_path *chp = to_channelpath(kobj_to_dev(kobj));
443 	ssize_t rc;
444 
445 	mutex_lock(&chp->lock);
446 	rc = memory_read_from_buffer(buf, count, &off, chp->desc_fmt3.util_str,
447 				     sizeof(chp->desc_fmt3.util_str));
448 	mutex_unlock(&chp->lock);
449 
450 	return rc;
451 }
452 static const BIN_ATTR_RO(util_string,
453 			 sizeof(((struct channel_path_desc_fmt3 *)0)->util_str));
454 
455 static const struct bin_attribute *const chp_bin_attrs[] = {
456 	&bin_attr_util_string,
457 	NULL,
458 };
459 
460 static struct attribute *chp_attrs[] = {
461 	&dev_attr_status.attr,
462 	&dev_attr_configure.attr,
463 	&dev_attr_type.attr,
464 	&dev_attr_cmg.attr,
465 	&dev_attr_shared.attr,
466 	&dev_attr_chid.attr,
467 	&dev_attr_chid_external.attr,
468 	&dev_attr_esc.attr,
469 	&dev_attr_speed_bps.attr,
470 	NULL,
471 };
472 static const struct attribute_group chp_attr_group = {
473 	.attrs = chp_attrs,
474 	.bin_attrs = chp_bin_attrs,
475 };
476 static const struct attribute_group *chp_attr_groups[] = {
477 	&chp_attr_group,
478 	NULL,
479 };
480 
481 static void chp_release(struct device *dev)
482 {
483 	struct channel_path *cp;
484 
485 	cp = to_channelpath(dev);
486 	kfree(cp);
487 }
488 
489 /**
490  * chp_update_desc - update channel-path description
491  * @chp: channel-path
492  *
493  * Update the channel-path description of the specified channel-path
494  * including channel measurement related information.
495  * Return zero on success, non-zero otherwise.
496  */
497 int chp_update_desc(struct channel_path *chp)
498 {
499 	int rc;
500 
501 	rc = chsc_determine_fmt0_channel_path_desc(chp->chpid, &chp->desc);
502 	if (rc)
503 		return rc;
504 
505 	/*
506 	 * Fetching the following data is optional. Not all machines or
507 	 * hypervisors implement the required chsc commands.
508 	 */
509 	chsc_determine_fmt1_channel_path_desc(chp->chpid, &chp->desc_fmt1);
510 	chsc_determine_fmt3_channel_path_desc(chp->chpid, &chp->desc_fmt3);
511 	chsc_get_channel_measurement_chars(chp);
512 
513 	return 0;
514 }
515 
516 /**
517  * chp_new - register a new channel-path
518  * @chpid: channel-path ID
519  *
520  * Create and register data structure representing new channel-path. Return
521  * zero on success, non-zero otherwise.
522  */
523 int chp_new(struct chp_id chpid)
524 {
525 	struct channel_subsystem *css = css_by_id(chpid.cssid);
526 	struct channel_path *chp;
527 	int ret = 0;
528 
529 	mutex_lock(&css->mutex);
530 	if (chp_is_registered(chpid))
531 		goto out;
532 
533 	chp = kzalloc(sizeof(struct channel_path), GFP_KERNEL);
534 	if (!chp) {
535 		ret = -ENOMEM;
536 		goto out;
537 	}
538 	/* fill in status, etc. */
539 	chp->chpid = chpid;
540 	chp->state = 1;
541 	chp->dev.parent = &css->device;
542 	chp->dev.groups = chp_attr_groups;
543 	chp->dev.release = chp_release;
544 	mutex_init(&chp->lock);
545 
546 	/* Obtain channel path description and fill it in. */
547 	ret = chp_update_desc(chp);
548 	if (ret)
549 		goto out_free;
550 	if ((chp->desc.flags & 0x80) == 0) {
551 		ret = -ENODEV;
552 		goto out_free;
553 	}
554 	dev_set_name(&chp->dev, "chp%x.%02x", chpid.cssid, chpid.id);
555 
556 	/* make it known to the system */
557 	ret = device_register(&chp->dev);
558 	if (ret) {
559 		CIO_MSG_EVENT(0, "Could not register chp%x.%02x: %d\n",
560 			      chpid.cssid, chpid.id, ret);
561 		put_device(&chp->dev);
562 		goto out;
563 	}
564 
565 	if (css->cm_enabled) {
566 		ret = chp_add_cmg_attr(chp);
567 		if (ret) {
568 			device_unregister(&chp->dev);
569 			goto out;
570 		}
571 	}
572 	css->chps[chpid.id] = chp;
573 	goto out;
574 out_free:
575 	kfree(chp);
576 out:
577 	mutex_unlock(&css->mutex);
578 	return ret;
579 }
580 
581 /**
582  * chp_get_chp_desc - return newly allocated channel-path description
583  * @chpid: channel-path ID
584  *
585  * On success return a newly allocated copy of the channel-path description
586  * data associated with the given channel-path ID. Return %NULL on error.
587  */
588 struct channel_path_desc_fmt0 *chp_get_chp_desc(struct chp_id chpid)
589 {
590 	struct channel_path *chp;
591 	struct channel_path_desc_fmt0 *desc;
592 
593 	chp = chpid_to_chp(chpid);
594 	if (!chp)
595 		return NULL;
596 	desc = kmalloc(sizeof(*desc), GFP_KERNEL);
597 	if (!desc)
598 		return NULL;
599 
600 	mutex_lock(&chp->lock);
601 	memcpy(desc, &chp->desc, sizeof(*desc));
602 	mutex_unlock(&chp->lock);
603 	return desc;
604 }
605 
606 /**
607  * chp_process_crw - process channel-path status change
608  * @crw0: channel report-word to handler
609  * @crw1: second channel-report word (always NULL)
610  * @overflow: crw overflow indication
611  *
612  * Handle channel-report-words indicating that the status of a channel-path
613  * has changed.
614  */
615 static void chp_process_crw(struct crw *crw0, struct crw *crw1,
616 			    int overflow)
617 {
618 	struct chp_id chpid;
619 
620 	if (overflow) {
621 		css_schedule_eval_all();
622 		return;
623 	}
624 	CIO_CRW_EVENT(2, "CRW reports slct=%d, oflw=%d, "
625 		      "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
626 		      crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
627 		      crw0->erc, crw0->rsid);
628 	/*
629 	 * Check for solicited machine checks. These are
630 	 * created by reset channel path and need not be
631 	 * handled here.
632 	 */
633 	if (crw0->slct) {
634 		CIO_CRW_EVENT(2, "solicited machine check for "
635 			      "channel path %02X\n", crw0->rsid);
636 		return;
637 	}
638 	chp_id_init(&chpid);
639 	chpid.id = crw0->rsid;
640 	switch (crw0->erc) {
641 	case CRW_ERC_IPARM: /* Path has come. */
642 	case CRW_ERC_INIT:
643 		chp_new(chpid);
644 		chsc_chp_online(chpid);
645 		break;
646 	case CRW_ERC_PERRI: /* Path has gone. */
647 	case CRW_ERC_PERRN:
648 		chsc_chp_offline(chpid);
649 		break;
650 	default:
651 		CIO_CRW_EVENT(2, "Don't know how to handle erc=%x\n",
652 			      crw0->erc);
653 	}
654 }
655 
656 int chp_ssd_get_mask(struct chsc_ssd_info *ssd, struct chp_link *link)
657 {
658 	int i;
659 	int mask;
660 
661 	for (i = 0; i < 8; i++) {
662 		mask = 0x80 >> i;
663 		if (!(ssd->path_mask & mask))
664 			continue;
665 		if (!chp_id_is_equal(&ssd->chpid[i], &link->chpid))
666 			continue;
667 		if ((ssd->fla_valid_mask & mask) &&
668 		    ((ssd->fla[i] & link->fla_mask) != link->fla))
669 			continue;
670 		return mask;
671 	}
672 	return 0;
673 }
674 EXPORT_SYMBOL_GPL(chp_ssd_get_mask);
675 
676 static inline int info_bit_num(struct chp_id id)
677 {
678 	return id.id + id.cssid * (__MAX_CHPID + 1);
679 }
680 
681 /* Force chp_info refresh on next call to info_validate(). */
682 static void info_expire(void)
683 {
684 	mutex_lock(&info_lock);
685 	chp_info_expires = jiffies - 1;
686 	mutex_unlock(&info_lock);
687 }
688 
689 /* Ensure that chp_info is up-to-date. */
690 static int info_update(void)
691 {
692 	int rc;
693 
694 	mutex_lock(&info_lock);
695 	rc = 0;
696 	if (time_after(jiffies, chp_info_expires)) {
697 		/* Data is too old, update. */
698 		rc = sclp_chp_read_info(&chp_info);
699 		if (!rc)
700 			chp_info_expires = jiffies + CHP_INFO_UPDATE_INTERVAL;
701 	}
702 	mutex_unlock(&info_lock);
703 
704 	return rc;
705 }
706 
707 /**
708  * chp_info_get_status - retrieve configure status of a channel-path
709  * @chpid: channel-path ID
710  *
711  * On success, return 0 for standby, 1 for configured, 2 for reserved,
712  * 3 for not recognized. Return negative error code on error.
713  */
714 int chp_info_get_status(struct chp_id chpid)
715 {
716 	int rc;
717 	int bit;
718 
719 	rc = info_update();
720 	if (rc)
721 		return rc;
722 
723 	bit = info_bit_num(chpid);
724 	mutex_lock(&info_lock);
725 	if (!chp_test_bit(chp_info.recognized, bit))
726 		rc = CHP_STATUS_NOT_RECOGNIZED;
727 	else if (chp_test_bit(chp_info.configured, bit))
728 		rc = CHP_STATUS_CONFIGURED;
729 	else if (chp_test_bit(chp_info.standby, bit))
730 		rc = CHP_STATUS_STANDBY;
731 	else
732 		rc = CHP_STATUS_RESERVED;
733 	mutex_unlock(&info_lock);
734 
735 	return rc;
736 }
737 
738 /* Return configure task for chpid. */
739 static enum cfg_task_t cfg_get_task(struct chp_id chpid)
740 {
741 	return chp_cfg_task[chpid.cssid][chpid.id];
742 }
743 
744 /* Set configure task for chpid. */
745 static void cfg_set_task(struct chp_id chpid, enum cfg_task_t cfg)
746 {
747 	chp_cfg_task[chpid.cssid][chpid.id] = cfg;
748 }
749 
750 /* Fetch the first configure task. Set chpid accordingly. */
751 static enum cfg_task_t chp_cfg_fetch_task(struct chp_id *chpid)
752 {
753 	enum cfg_task_t t = cfg_none;
754 
755 	chp_id_for_each(chpid) {
756 		t = cfg_get_task(*chpid);
757 		if (t != cfg_none)
758 			break;
759 	}
760 
761 	return t;
762 }
763 
764 /* Perform one configure/deconfigure request. Reschedule work function until
765  * last request. */
766 static void cfg_func(struct work_struct *work)
767 {
768 	struct chp_id chpid;
769 	enum cfg_task_t t;
770 	int rc;
771 
772 	spin_lock(&cfg_lock);
773 	t = chp_cfg_fetch_task(&chpid);
774 	spin_unlock(&cfg_lock);
775 
776 	switch (t) {
777 	case cfg_configure:
778 		rc = sclp_chp_configure(chpid);
779 		if (rc)
780 			CIO_MSG_EVENT(2, "chp: sclp_chp_configure(%x.%02x)="
781 				      "%d\n", chpid.cssid, chpid.id, rc);
782 		else {
783 			info_expire();
784 			chsc_chp_online(chpid);
785 		}
786 		break;
787 	case cfg_deconfigure:
788 		rc = sclp_chp_deconfigure(chpid);
789 		if (rc)
790 			CIO_MSG_EVENT(2, "chp: sclp_chp_deconfigure(%x.%02x)="
791 				      "%d\n", chpid.cssid, chpid.id, rc);
792 		else {
793 			info_expire();
794 			chsc_chp_offline(chpid);
795 		}
796 		break;
797 	case cfg_none:
798 		/* Get updated information after last change. */
799 		info_update();
800 		wake_up_interruptible(&cfg_wait_queue);
801 		return;
802 	}
803 	spin_lock(&cfg_lock);
804 	if (t == cfg_get_task(chpid))
805 		cfg_set_task(chpid, cfg_none);
806 	spin_unlock(&cfg_lock);
807 	schedule_work(&cfg_work);
808 }
809 
810 /**
811  * chp_cfg_schedule - schedule chpid configuration request
812  * @chpid: channel-path ID
813  * @configure: Non-zero for configure, zero for deconfigure
814  *
815  * Schedule a channel-path configuration/deconfiguration request.
816  */
817 void chp_cfg_schedule(struct chp_id chpid, int configure)
818 {
819 	CIO_MSG_EVENT(2, "chp_cfg_sched%x.%02x=%d\n", chpid.cssid, chpid.id,
820 		      configure);
821 	spin_lock(&cfg_lock);
822 	cfg_set_task(chpid, configure ? cfg_configure : cfg_deconfigure);
823 	spin_unlock(&cfg_lock);
824 	schedule_work(&cfg_work);
825 }
826 
827 /**
828  * chp_cfg_cancel_deconfigure - cancel chpid deconfiguration request
829  * @chpid: channel-path ID
830  *
831  * Cancel an active channel-path deconfiguration request if it has not yet
832  * been performed.
833  */
834 void chp_cfg_cancel_deconfigure(struct chp_id chpid)
835 {
836 	CIO_MSG_EVENT(2, "chp_cfg_cancel:%x.%02x\n", chpid.cssid, chpid.id);
837 	spin_lock(&cfg_lock);
838 	if (cfg_get_task(chpid) == cfg_deconfigure)
839 		cfg_set_task(chpid, cfg_none);
840 	spin_unlock(&cfg_lock);
841 }
842 
843 static bool cfg_idle(void)
844 {
845 	struct chp_id chpid;
846 	enum cfg_task_t t;
847 
848 	spin_lock(&cfg_lock);
849 	t = chp_cfg_fetch_task(&chpid);
850 	spin_unlock(&cfg_lock);
851 
852 	return t == cfg_none;
853 }
854 
855 static int cfg_wait_idle(void)
856 {
857 	if (wait_event_interruptible(cfg_wait_queue, cfg_idle()))
858 		return -ERESTARTSYS;
859 	return 0;
860 }
861 
862 static int __init chp_init(void)
863 {
864 	struct chp_id chpid;
865 	int state, ret;
866 
867 	ret = crw_register_handler(CRW_RSC_CPATH, chp_process_crw);
868 	if (ret)
869 		return ret;
870 	INIT_WORK(&cfg_work, cfg_func);
871 	if (info_update())
872 		return 0;
873 	/* Register available channel-paths. */
874 	chp_id_for_each(&chpid) {
875 		state = chp_info_get_status(chpid);
876 		if (state == CHP_STATUS_CONFIGURED ||
877 		    state == CHP_STATUS_STANDBY)
878 			chp_new(chpid);
879 	}
880 
881 	return 0;
882 }
883 
884 subsys_initcall(chp_init);
885