xref: /openbmc/linux/drivers/s390/cio/css.c (revision ee89bd6b)
1 /*
2  * driver for channel subsystem
3  *
4  * Copyright IBM Corp. 2002, 2010
5  *
6  * Author(s): Arnd Bergmann (arndb@de.ibm.com)
7  *	      Cornelia Huck (cornelia.huck@de.ibm.com)
8  */
9 
10 #define KMSG_COMPONENT "cio"
11 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
12 
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/device.h>
16 #include <linux/slab.h>
17 #include <linux/errno.h>
18 #include <linux/list.h>
19 #include <linux/reboot.h>
20 #include <linux/suspend.h>
21 #include <linux/proc_fs.h>
22 #include <asm/isc.h>
23 #include <asm/crw.h>
24 
25 #include "css.h"
26 #include "cio.h"
27 #include "cio_debug.h"
28 #include "ioasm.h"
29 #include "chsc.h"
30 #include "device.h"
31 #include "idset.h"
32 #include "chp.h"
33 
34 int css_init_done = 0;
35 int max_ssid;
36 
37 struct channel_subsystem *channel_subsystems[__MAX_CSSID + 1];
38 static struct bus_type css_bus_type;
39 
40 int
41 for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
42 {
43 	struct subchannel_id schid;
44 	int ret;
45 
46 	init_subchannel_id(&schid);
47 	ret = -ENODEV;
48 	do {
49 		do {
50 			ret = fn(schid, data);
51 			if (ret)
52 				break;
53 		} while (schid.sch_no++ < __MAX_SUBCHANNEL);
54 		schid.sch_no = 0;
55 	} while (schid.ssid++ < max_ssid);
56 	return ret;
57 }
58 
59 struct cb_data {
60 	void *data;
61 	struct idset *set;
62 	int (*fn_known_sch)(struct subchannel *, void *);
63 	int (*fn_unknown_sch)(struct subchannel_id, void *);
64 };
65 
66 static int call_fn_known_sch(struct device *dev, void *data)
67 {
68 	struct subchannel *sch = to_subchannel(dev);
69 	struct cb_data *cb = data;
70 	int rc = 0;
71 
72 	idset_sch_del(cb->set, sch->schid);
73 	if (cb->fn_known_sch)
74 		rc = cb->fn_known_sch(sch, cb->data);
75 	return rc;
76 }
77 
78 static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
79 {
80 	struct cb_data *cb = data;
81 	int rc = 0;
82 
83 	if (idset_sch_contains(cb->set, schid))
84 		rc = cb->fn_unknown_sch(schid, cb->data);
85 	return rc;
86 }
87 
88 static int call_fn_all_sch(struct subchannel_id schid, void *data)
89 {
90 	struct cb_data *cb = data;
91 	struct subchannel *sch;
92 	int rc = 0;
93 
94 	sch = get_subchannel_by_schid(schid);
95 	if (sch) {
96 		if (cb->fn_known_sch)
97 			rc = cb->fn_known_sch(sch, cb->data);
98 		put_device(&sch->dev);
99 	} else {
100 		if (cb->fn_unknown_sch)
101 			rc = cb->fn_unknown_sch(schid, cb->data);
102 	}
103 
104 	return rc;
105 }
106 
107 int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
108 			       int (*fn_unknown)(struct subchannel_id,
109 			       void *), void *data)
110 {
111 	struct cb_data cb;
112 	int rc;
113 
114 	cb.data = data;
115 	cb.fn_known_sch = fn_known;
116 	cb.fn_unknown_sch = fn_unknown;
117 
118 	cb.set = idset_sch_new();
119 	if (!cb.set)
120 		/* fall back to brute force scanning in case of oom */
121 		return for_each_subchannel(call_fn_all_sch, &cb);
122 
123 	idset_fill(cb.set);
124 
125 	/* Process registered subchannels. */
126 	rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
127 	if (rc)
128 		goto out;
129 	/* Process unregistered subchannels. */
130 	if (fn_unknown)
131 		rc = for_each_subchannel(call_fn_unknown_sch, &cb);
132 out:
133 	idset_free(cb.set);
134 
135 	return rc;
136 }
137 
138 static void css_sch_todo(struct work_struct *work);
139 
140 static int css_sch_create_locks(struct subchannel *sch)
141 {
142 	sch->lock = kmalloc(sizeof(*sch->lock), GFP_KERNEL);
143 	if (!sch->lock)
144 		return -ENOMEM;
145 
146 	spin_lock_init(sch->lock);
147 	mutex_init(&sch->reg_mutex);
148 
149 	return 0;
150 }
151 
152 static void css_subchannel_release(struct device *dev)
153 {
154 	struct subchannel *sch = to_subchannel(dev);
155 
156 	sch->config.intparm = 0;
157 	cio_commit_config(sch);
158 	kfree(sch->lock);
159 	kfree(sch);
160 }
161 
162 struct subchannel *css_alloc_subchannel(struct subchannel_id schid)
163 {
164 	struct subchannel *sch;
165 	int ret;
166 
167 	sch = kzalloc(sizeof(*sch), GFP_KERNEL | GFP_DMA);
168 	if (!sch)
169 		return ERR_PTR(-ENOMEM);
170 
171 	ret = cio_validate_subchannel(sch, schid);
172 	if (ret < 0)
173 		goto err;
174 
175 	ret = css_sch_create_locks(sch);
176 	if (ret)
177 		goto err;
178 
179 	INIT_WORK(&sch->todo_work, css_sch_todo);
180 	sch->dev.release = &css_subchannel_release;
181 	device_initialize(&sch->dev);
182 	return sch;
183 
184 err:
185 	kfree(sch);
186 	return ERR_PTR(ret);
187 }
188 
189 static int css_sch_device_register(struct subchannel *sch)
190 {
191 	int ret;
192 
193 	mutex_lock(&sch->reg_mutex);
194 	dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
195 		     sch->schid.sch_no);
196 	ret = device_add(&sch->dev);
197 	mutex_unlock(&sch->reg_mutex);
198 	return ret;
199 }
200 
201 /**
202  * css_sch_device_unregister - unregister a subchannel
203  * @sch: subchannel to be unregistered
204  */
205 void css_sch_device_unregister(struct subchannel *sch)
206 {
207 	mutex_lock(&sch->reg_mutex);
208 	if (device_is_registered(&sch->dev))
209 		device_unregister(&sch->dev);
210 	mutex_unlock(&sch->reg_mutex);
211 }
212 EXPORT_SYMBOL_GPL(css_sch_device_unregister);
213 
214 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
215 {
216 	int i;
217 	int mask;
218 
219 	memset(ssd, 0, sizeof(struct chsc_ssd_info));
220 	ssd->path_mask = pmcw->pim;
221 	for (i = 0; i < 8; i++) {
222 		mask = 0x80 >> i;
223 		if (pmcw->pim & mask) {
224 			chp_id_init(&ssd->chpid[i]);
225 			ssd->chpid[i].id = pmcw->chpid[i];
226 		}
227 	}
228 }
229 
230 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
231 {
232 	int i;
233 	int mask;
234 
235 	for (i = 0; i < 8; i++) {
236 		mask = 0x80 >> i;
237 		if (ssd->path_mask & mask)
238 			if (!chp_is_registered(ssd->chpid[i]))
239 				chp_new(ssd->chpid[i]);
240 	}
241 }
242 
243 void css_update_ssd_info(struct subchannel *sch)
244 {
245 	int ret;
246 
247 	ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
248 	if (ret)
249 		ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
250 
251 	ssd_register_chpids(&sch->ssd_info);
252 }
253 
254 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
255 			 char *buf)
256 {
257 	struct subchannel *sch = to_subchannel(dev);
258 
259 	return sprintf(buf, "%01x\n", sch->st);
260 }
261 
262 static DEVICE_ATTR(type, 0444, type_show, NULL);
263 
264 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
265 			     char *buf)
266 {
267 	struct subchannel *sch = to_subchannel(dev);
268 
269 	return sprintf(buf, "css:t%01X\n", sch->st);
270 }
271 
272 static DEVICE_ATTR(modalias, 0444, modalias_show, NULL);
273 
274 static struct attribute *subch_attrs[] = {
275 	&dev_attr_type.attr,
276 	&dev_attr_modalias.attr,
277 	NULL,
278 };
279 
280 static struct attribute_group subch_attr_group = {
281 	.attrs = subch_attrs,
282 };
283 
284 static const struct attribute_group *default_subch_attr_groups[] = {
285 	&subch_attr_group,
286 	NULL,
287 };
288 
289 int css_register_subchannel(struct subchannel *sch)
290 {
291 	int ret;
292 
293 	/* Initialize the subchannel structure */
294 	sch->dev.parent = &channel_subsystems[0]->device;
295 	sch->dev.bus = &css_bus_type;
296 	sch->dev.groups = default_subch_attr_groups;
297 	/*
298 	 * We don't want to generate uevents for I/O subchannels that don't
299 	 * have a working ccw device behind them since they will be
300 	 * unregistered before they can be used anyway, so we delay the add
301 	 * uevent until after device recognition was successful.
302 	 * Note that we suppress the uevent for all subchannel types;
303 	 * the subchannel driver can decide itself when it wants to inform
304 	 * userspace of its existence.
305 	 */
306 	dev_set_uevent_suppress(&sch->dev, 1);
307 	css_update_ssd_info(sch);
308 	/* make it known to the system */
309 	ret = css_sch_device_register(sch);
310 	if (ret) {
311 		CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
312 			      sch->schid.ssid, sch->schid.sch_no, ret);
313 		return ret;
314 	}
315 	if (!sch->driver) {
316 		/*
317 		 * No driver matched. Generate the uevent now so that
318 		 * a fitting driver module may be loaded based on the
319 		 * modalias.
320 		 */
321 		dev_set_uevent_suppress(&sch->dev, 0);
322 		kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
323 	}
324 	return ret;
325 }
326 
327 static int css_probe_device(struct subchannel_id schid)
328 {
329 	struct subchannel *sch;
330 	int ret;
331 
332 	sch = css_alloc_subchannel(schid);
333 	if (IS_ERR(sch))
334 		return PTR_ERR(sch);
335 
336 	ret = css_register_subchannel(sch);
337 	if (ret)
338 		put_device(&sch->dev);
339 
340 	return ret;
341 }
342 
343 static int
344 check_subchannel(struct device * dev, void * data)
345 {
346 	struct subchannel *sch;
347 	struct subchannel_id *schid = data;
348 
349 	sch = to_subchannel(dev);
350 	return schid_equal(&sch->schid, schid);
351 }
352 
353 struct subchannel *
354 get_subchannel_by_schid(struct subchannel_id schid)
355 {
356 	struct device *dev;
357 
358 	dev = bus_find_device(&css_bus_type, NULL,
359 			      &schid, check_subchannel);
360 
361 	return dev ? to_subchannel(dev) : NULL;
362 }
363 
364 /**
365  * css_sch_is_valid() - check if a subchannel is valid
366  * @schib: subchannel information block for the subchannel
367  */
368 int css_sch_is_valid(struct schib *schib)
369 {
370 	if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
371 		return 0;
372 	if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
373 		return 0;
374 	return 1;
375 }
376 EXPORT_SYMBOL_GPL(css_sch_is_valid);
377 
378 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
379 {
380 	struct schib schib;
381 
382 	if (!slow) {
383 		/* Will be done on the slow path. */
384 		return -EAGAIN;
385 	}
386 	if (stsch_err(schid, &schib)) {
387 		/* Subchannel is not provided. */
388 		return -ENXIO;
389 	}
390 	if (!css_sch_is_valid(&schib)) {
391 		/* Unusable - ignore. */
392 		return 0;
393 	}
394 	CIO_MSG_EVENT(4, "event: sch 0.%x.%04x, new\n", schid.ssid,
395 		      schid.sch_no);
396 
397 	return css_probe_device(schid);
398 }
399 
400 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
401 {
402 	int ret = 0;
403 
404 	if (sch->driver) {
405 		if (sch->driver->sch_event)
406 			ret = sch->driver->sch_event(sch, slow);
407 		else
408 			dev_dbg(&sch->dev,
409 				"Got subchannel machine check but "
410 				"no sch_event handler provided.\n");
411 	}
412 	if (ret != 0 && ret != -EAGAIN) {
413 		CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
414 			      sch->schid.ssid, sch->schid.sch_no, ret);
415 	}
416 	return ret;
417 }
418 
419 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
420 {
421 	struct subchannel *sch;
422 	int ret;
423 
424 	sch = get_subchannel_by_schid(schid);
425 	if (sch) {
426 		ret = css_evaluate_known_subchannel(sch, slow);
427 		put_device(&sch->dev);
428 	} else
429 		ret = css_evaluate_new_subchannel(schid, slow);
430 	if (ret == -EAGAIN)
431 		css_schedule_eval(schid);
432 }
433 
434 /**
435  * css_sched_sch_todo - schedule a subchannel operation
436  * @sch: subchannel
437  * @todo: todo
438  *
439  * Schedule the operation identified by @todo to be performed on the slow path
440  * workqueue. Do nothing if another operation with higher priority is already
441  * scheduled. Needs to be called with subchannel lock held.
442  */
443 void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)
444 {
445 	CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",
446 		      sch->schid.ssid, sch->schid.sch_no, todo);
447 	if (sch->todo >= todo)
448 		return;
449 	/* Get workqueue ref. */
450 	if (!get_device(&sch->dev))
451 		return;
452 	sch->todo = todo;
453 	if (!queue_work(cio_work_q, &sch->todo_work)) {
454 		/* Already queued, release workqueue ref. */
455 		put_device(&sch->dev);
456 	}
457 }
458 EXPORT_SYMBOL_GPL(css_sched_sch_todo);
459 
460 static void css_sch_todo(struct work_struct *work)
461 {
462 	struct subchannel *sch;
463 	enum sch_todo todo;
464 	int ret;
465 
466 	sch = container_of(work, struct subchannel, todo_work);
467 	/* Find out todo. */
468 	spin_lock_irq(sch->lock);
469 	todo = sch->todo;
470 	CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,
471 		      sch->schid.sch_no, todo);
472 	sch->todo = SCH_TODO_NOTHING;
473 	spin_unlock_irq(sch->lock);
474 	/* Perform todo. */
475 	switch (todo) {
476 	case SCH_TODO_NOTHING:
477 		break;
478 	case SCH_TODO_EVAL:
479 		ret = css_evaluate_known_subchannel(sch, 1);
480 		if (ret == -EAGAIN) {
481 			spin_lock_irq(sch->lock);
482 			css_sched_sch_todo(sch, todo);
483 			spin_unlock_irq(sch->lock);
484 		}
485 		break;
486 	case SCH_TODO_UNREG:
487 		css_sch_device_unregister(sch);
488 		break;
489 	}
490 	/* Release workqueue ref. */
491 	put_device(&sch->dev);
492 }
493 
494 static struct idset *slow_subchannel_set;
495 static spinlock_t slow_subchannel_lock;
496 static wait_queue_head_t css_eval_wq;
497 static atomic_t css_eval_scheduled;
498 
499 static int __init slow_subchannel_init(void)
500 {
501 	spin_lock_init(&slow_subchannel_lock);
502 	atomic_set(&css_eval_scheduled, 0);
503 	init_waitqueue_head(&css_eval_wq);
504 	slow_subchannel_set = idset_sch_new();
505 	if (!slow_subchannel_set) {
506 		CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
507 		return -ENOMEM;
508 	}
509 	return 0;
510 }
511 
512 static int slow_eval_known_fn(struct subchannel *sch, void *data)
513 {
514 	int eval;
515 	int rc;
516 
517 	spin_lock_irq(&slow_subchannel_lock);
518 	eval = idset_sch_contains(slow_subchannel_set, sch->schid);
519 	idset_sch_del(slow_subchannel_set, sch->schid);
520 	spin_unlock_irq(&slow_subchannel_lock);
521 	if (eval) {
522 		rc = css_evaluate_known_subchannel(sch, 1);
523 		if (rc == -EAGAIN)
524 			css_schedule_eval(sch->schid);
525 	}
526 	return 0;
527 }
528 
529 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
530 {
531 	int eval;
532 	int rc = 0;
533 
534 	spin_lock_irq(&slow_subchannel_lock);
535 	eval = idset_sch_contains(slow_subchannel_set, schid);
536 	idset_sch_del(slow_subchannel_set, schid);
537 	spin_unlock_irq(&slow_subchannel_lock);
538 	if (eval) {
539 		rc = css_evaluate_new_subchannel(schid, 1);
540 		switch (rc) {
541 		case -EAGAIN:
542 			css_schedule_eval(schid);
543 			rc = 0;
544 			break;
545 		case -ENXIO:
546 		case -ENOMEM:
547 		case -EIO:
548 			/* These should abort looping */
549 			idset_sch_del_subseq(slow_subchannel_set, schid);
550 			break;
551 		default:
552 			rc = 0;
553 		}
554 	}
555 	return rc;
556 }
557 
558 static void css_slow_path_func(struct work_struct *unused)
559 {
560 	unsigned long flags;
561 
562 	CIO_TRACE_EVENT(4, "slowpath");
563 	for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
564 				   NULL);
565 	spin_lock_irqsave(&slow_subchannel_lock, flags);
566 	if (idset_is_empty(slow_subchannel_set)) {
567 		atomic_set(&css_eval_scheduled, 0);
568 		wake_up(&css_eval_wq);
569 	}
570 	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
571 }
572 
573 static DECLARE_WORK(slow_path_work, css_slow_path_func);
574 struct workqueue_struct *cio_work_q;
575 
576 void css_schedule_eval(struct subchannel_id schid)
577 {
578 	unsigned long flags;
579 
580 	spin_lock_irqsave(&slow_subchannel_lock, flags);
581 	idset_sch_add(slow_subchannel_set, schid);
582 	atomic_set(&css_eval_scheduled, 1);
583 	queue_work(cio_work_q, &slow_path_work);
584 	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
585 }
586 
587 void css_schedule_eval_all(void)
588 {
589 	unsigned long flags;
590 
591 	spin_lock_irqsave(&slow_subchannel_lock, flags);
592 	idset_fill(slow_subchannel_set);
593 	atomic_set(&css_eval_scheduled, 1);
594 	queue_work(cio_work_q, &slow_path_work);
595 	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
596 }
597 
598 static int __unset_registered(struct device *dev, void *data)
599 {
600 	struct idset *set = data;
601 	struct subchannel *sch = to_subchannel(dev);
602 
603 	idset_sch_del(set, sch->schid);
604 	return 0;
605 }
606 
607 static void css_schedule_eval_all_unreg(void)
608 {
609 	unsigned long flags;
610 	struct idset *unreg_set;
611 
612 	/* Find unregistered subchannels. */
613 	unreg_set = idset_sch_new();
614 	if (!unreg_set) {
615 		/* Fallback. */
616 		css_schedule_eval_all();
617 		return;
618 	}
619 	idset_fill(unreg_set);
620 	bus_for_each_dev(&css_bus_type, NULL, unreg_set, __unset_registered);
621 	/* Apply to slow_subchannel_set. */
622 	spin_lock_irqsave(&slow_subchannel_lock, flags);
623 	idset_add_set(slow_subchannel_set, unreg_set);
624 	atomic_set(&css_eval_scheduled, 1);
625 	queue_work(cio_work_q, &slow_path_work);
626 	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
627 	idset_free(unreg_set);
628 }
629 
630 void css_wait_for_slow_path(void)
631 {
632 	flush_workqueue(cio_work_q);
633 }
634 
635 /* Schedule reprobing of all unregistered subchannels. */
636 void css_schedule_reprobe(void)
637 {
638 	css_schedule_eval_all_unreg();
639 }
640 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
641 
642 /*
643  * Called from the machine check handler for subchannel report words.
644  */
645 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
646 {
647 	struct subchannel_id mchk_schid;
648 	struct subchannel *sch;
649 
650 	if (overflow) {
651 		css_schedule_eval_all();
652 		return;
653 	}
654 	CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
655 		      "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
656 		      crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
657 		      crw0->erc, crw0->rsid);
658 	if (crw1)
659 		CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
660 			      "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
661 			      crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
662 			      crw1->anc, crw1->erc, crw1->rsid);
663 	init_subchannel_id(&mchk_schid);
664 	mchk_schid.sch_no = crw0->rsid;
665 	if (crw1)
666 		mchk_schid.ssid = (crw1->rsid >> 4) & 3;
667 
668 	if (crw0->erc == CRW_ERC_PMOD) {
669 		sch = get_subchannel_by_schid(mchk_schid);
670 		if (sch) {
671 			css_update_ssd_info(sch);
672 			put_device(&sch->dev);
673 		}
674 	}
675 	/*
676 	 * Since we are always presented with IPI in the CRW, we have to
677 	 * use stsch() to find out if the subchannel in question has come
678 	 * or gone.
679 	 */
680 	css_evaluate_subchannel(mchk_schid, 0);
681 }
682 
683 static void __init
684 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
685 {
686 	struct cpuid cpu_id;
687 
688 	if (css_general_characteristics.mcss) {
689 		css->global_pgid.pgid_high.ext_cssid.version = 0x80;
690 		css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
691 	} else {
692 #ifdef CONFIG_SMP
693 		css->global_pgid.pgid_high.cpu_addr = stap();
694 #else
695 		css->global_pgid.pgid_high.cpu_addr = 0;
696 #endif
697 	}
698 	get_cpu_id(&cpu_id);
699 	css->global_pgid.cpu_id = cpu_id.ident;
700 	css->global_pgid.cpu_model = cpu_id.machine;
701 	css->global_pgid.tod_high = tod_high;
702 
703 }
704 
705 static void
706 channel_subsystem_release(struct device *dev)
707 {
708 	struct channel_subsystem *css;
709 
710 	css = to_css(dev);
711 	mutex_destroy(&css->mutex);
712 	if (css->pseudo_subchannel) {
713 		/* Implies that it has been generated but never registered. */
714 		css_subchannel_release(&css->pseudo_subchannel->dev);
715 		css->pseudo_subchannel = NULL;
716 	}
717 	kfree(css);
718 }
719 
720 static ssize_t
721 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
722 		   char *buf)
723 {
724 	struct channel_subsystem *css = to_css(dev);
725 	int ret;
726 
727 	if (!css)
728 		return 0;
729 	mutex_lock(&css->mutex);
730 	ret = sprintf(buf, "%x\n", css->cm_enabled);
731 	mutex_unlock(&css->mutex);
732 	return ret;
733 }
734 
735 static ssize_t
736 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
737 		    const char *buf, size_t count)
738 {
739 	struct channel_subsystem *css = to_css(dev);
740 	int ret;
741 	unsigned long val;
742 
743 	ret = strict_strtoul(buf, 16, &val);
744 	if (ret)
745 		return ret;
746 	mutex_lock(&css->mutex);
747 	switch (val) {
748 	case 0:
749 		ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
750 		break;
751 	case 1:
752 		ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
753 		break;
754 	default:
755 		ret = -EINVAL;
756 	}
757 	mutex_unlock(&css->mutex);
758 	return ret < 0 ? ret : count;
759 }
760 
761 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
762 
763 static int __init setup_css(int nr)
764 {
765 	u32 tod_high;
766 	int ret;
767 	struct channel_subsystem *css;
768 
769 	css = channel_subsystems[nr];
770 	memset(css, 0, sizeof(struct channel_subsystem));
771 	css->pseudo_subchannel =
772 		kzalloc(sizeof(*css->pseudo_subchannel), GFP_KERNEL);
773 	if (!css->pseudo_subchannel)
774 		return -ENOMEM;
775 	css->pseudo_subchannel->dev.parent = &css->device;
776 	css->pseudo_subchannel->dev.release = css_subchannel_release;
777 	dev_set_name(&css->pseudo_subchannel->dev, "defunct");
778 	mutex_init(&css->pseudo_subchannel->reg_mutex);
779 	ret = css_sch_create_locks(css->pseudo_subchannel);
780 	if (ret) {
781 		kfree(css->pseudo_subchannel);
782 		return ret;
783 	}
784 	mutex_init(&css->mutex);
785 	css->valid = 1;
786 	css->cssid = nr;
787 	dev_set_name(&css->device, "css%x", nr);
788 	css->device.release = channel_subsystem_release;
789 	tod_high = (u32) (get_tod_clock() >> 32);
790 	css_generate_pgid(css, tod_high);
791 	return 0;
792 }
793 
794 static int css_reboot_event(struct notifier_block *this,
795 			    unsigned long event,
796 			    void *ptr)
797 {
798 	int ret, i;
799 
800 	ret = NOTIFY_DONE;
801 	for (i = 0; i <= __MAX_CSSID; i++) {
802 		struct channel_subsystem *css;
803 
804 		css = channel_subsystems[i];
805 		mutex_lock(&css->mutex);
806 		if (css->cm_enabled)
807 			if (chsc_secm(css, 0))
808 				ret = NOTIFY_BAD;
809 		mutex_unlock(&css->mutex);
810 	}
811 
812 	return ret;
813 }
814 
815 static struct notifier_block css_reboot_notifier = {
816 	.notifier_call = css_reboot_event,
817 };
818 
819 /*
820  * Since the css devices are neither on a bus nor have a class
821  * nor have a special device type, we cannot stop/restart channel
822  * path measurements via the normal suspend/resume callbacks, but have
823  * to use notifiers.
824  */
825 static int css_power_event(struct notifier_block *this, unsigned long event,
826 			   void *ptr)
827 {
828 	int ret, i;
829 
830 	switch (event) {
831 	case PM_HIBERNATION_PREPARE:
832 	case PM_SUSPEND_PREPARE:
833 		ret = NOTIFY_DONE;
834 		for (i = 0; i <= __MAX_CSSID; i++) {
835 			struct channel_subsystem *css;
836 
837 			css = channel_subsystems[i];
838 			mutex_lock(&css->mutex);
839 			if (!css->cm_enabled) {
840 				mutex_unlock(&css->mutex);
841 				continue;
842 			}
843 			ret = __chsc_do_secm(css, 0);
844 			ret = notifier_from_errno(ret);
845 			mutex_unlock(&css->mutex);
846 		}
847 		break;
848 	case PM_POST_HIBERNATION:
849 	case PM_POST_SUSPEND:
850 		ret = NOTIFY_DONE;
851 		for (i = 0; i <= __MAX_CSSID; i++) {
852 			struct channel_subsystem *css;
853 
854 			css = channel_subsystems[i];
855 			mutex_lock(&css->mutex);
856 			if (!css->cm_enabled) {
857 				mutex_unlock(&css->mutex);
858 				continue;
859 			}
860 			ret = __chsc_do_secm(css, 1);
861 			ret = notifier_from_errno(ret);
862 			mutex_unlock(&css->mutex);
863 		}
864 		/* search for subchannels, which appeared during hibernation */
865 		css_schedule_reprobe();
866 		break;
867 	default:
868 		ret = NOTIFY_DONE;
869 	}
870 	return ret;
871 
872 }
873 static struct notifier_block css_power_notifier = {
874 	.notifier_call = css_power_event,
875 };
876 
877 /*
878  * Now that the driver core is running, we can setup our channel subsystem.
879  * The struct subchannel's are created during probing.
880  */
881 static int __init css_bus_init(void)
882 {
883 	int ret, i;
884 
885 	ret = chsc_init();
886 	if (ret)
887 		return ret;
888 
889 	chsc_determine_css_characteristics();
890 	/* Try to enable MSS. */
891 	ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
892 	if (ret)
893 		max_ssid = 0;
894 	else /* Success. */
895 		max_ssid = __MAX_SSID;
896 
897 	ret = slow_subchannel_init();
898 	if (ret)
899 		goto out;
900 
901 	ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
902 	if (ret)
903 		goto out;
904 
905 	if ((ret = bus_register(&css_bus_type)))
906 		goto out;
907 
908 	/* Setup css structure. */
909 	for (i = 0; i <= __MAX_CSSID; i++) {
910 		struct channel_subsystem *css;
911 
912 		css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
913 		if (!css) {
914 			ret = -ENOMEM;
915 			goto out_unregister;
916 		}
917 		channel_subsystems[i] = css;
918 		ret = setup_css(i);
919 		if (ret) {
920 			kfree(channel_subsystems[i]);
921 			goto out_unregister;
922 		}
923 		ret = device_register(&css->device);
924 		if (ret) {
925 			put_device(&css->device);
926 			goto out_unregister;
927 		}
928 		if (css_chsc_characteristics.secm) {
929 			ret = device_create_file(&css->device,
930 						 &dev_attr_cm_enable);
931 			if (ret)
932 				goto out_device;
933 		}
934 		ret = device_register(&css->pseudo_subchannel->dev);
935 		if (ret) {
936 			put_device(&css->pseudo_subchannel->dev);
937 			goto out_file;
938 		}
939 	}
940 	ret = register_reboot_notifier(&css_reboot_notifier);
941 	if (ret)
942 		goto out_unregister;
943 	ret = register_pm_notifier(&css_power_notifier);
944 	if (ret) {
945 		unregister_reboot_notifier(&css_reboot_notifier);
946 		goto out_unregister;
947 	}
948 	css_init_done = 1;
949 
950 	/* Enable default isc for I/O subchannels. */
951 	isc_register(IO_SCH_ISC);
952 
953 	return 0;
954 out_file:
955 	if (css_chsc_characteristics.secm)
956 		device_remove_file(&channel_subsystems[i]->device,
957 				   &dev_attr_cm_enable);
958 out_device:
959 	device_unregister(&channel_subsystems[i]->device);
960 out_unregister:
961 	while (i > 0) {
962 		struct channel_subsystem *css;
963 
964 		i--;
965 		css = channel_subsystems[i];
966 		device_unregister(&css->pseudo_subchannel->dev);
967 		css->pseudo_subchannel = NULL;
968 		if (css_chsc_characteristics.secm)
969 			device_remove_file(&css->device,
970 					   &dev_attr_cm_enable);
971 		device_unregister(&css->device);
972 	}
973 	bus_unregister(&css_bus_type);
974 out:
975 	crw_unregister_handler(CRW_RSC_SCH);
976 	idset_free(slow_subchannel_set);
977 	chsc_init_cleanup();
978 	pr_alert("The CSS device driver initialization failed with "
979 		 "errno=%d\n", ret);
980 	return ret;
981 }
982 
983 static void __init css_bus_cleanup(void)
984 {
985 	struct channel_subsystem *css;
986 	int i;
987 
988 	for (i = 0; i <= __MAX_CSSID; i++) {
989 		css = channel_subsystems[i];
990 		device_unregister(&css->pseudo_subchannel->dev);
991 		css->pseudo_subchannel = NULL;
992 		if (css_chsc_characteristics.secm)
993 			device_remove_file(&css->device, &dev_attr_cm_enable);
994 		device_unregister(&css->device);
995 	}
996 	bus_unregister(&css_bus_type);
997 	crw_unregister_handler(CRW_RSC_SCH);
998 	idset_free(slow_subchannel_set);
999 	chsc_init_cleanup();
1000 	isc_unregister(IO_SCH_ISC);
1001 }
1002 
1003 static int __init channel_subsystem_init(void)
1004 {
1005 	int ret;
1006 
1007 	ret = css_bus_init();
1008 	if (ret)
1009 		return ret;
1010 	cio_work_q = create_singlethread_workqueue("cio");
1011 	if (!cio_work_q) {
1012 		ret = -ENOMEM;
1013 		goto out_bus;
1014 	}
1015 	ret = io_subchannel_init();
1016 	if (ret)
1017 		goto out_wq;
1018 
1019 	return ret;
1020 out_wq:
1021 	destroy_workqueue(cio_work_q);
1022 out_bus:
1023 	css_bus_cleanup();
1024 	return ret;
1025 }
1026 subsys_initcall(channel_subsystem_init);
1027 
1028 static int css_settle(struct device_driver *drv, void *unused)
1029 {
1030 	struct css_driver *cssdrv = to_cssdriver(drv);
1031 
1032 	if (cssdrv->settle)
1033 		return cssdrv->settle();
1034 	return 0;
1035 }
1036 
1037 int css_complete_work(void)
1038 {
1039 	int ret;
1040 
1041 	/* Wait for the evaluation of subchannels to finish. */
1042 	ret = wait_event_interruptible(css_eval_wq,
1043 				       atomic_read(&css_eval_scheduled) == 0);
1044 	if (ret)
1045 		return -EINTR;
1046 	flush_workqueue(cio_work_q);
1047 	/* Wait for the subchannel type specific initialization to finish */
1048 	return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
1049 }
1050 
1051 
1052 /*
1053  * Wait for the initialization of devices to finish, to make sure we are
1054  * done with our setup if the search for the root device starts.
1055  */
1056 static int __init channel_subsystem_init_sync(void)
1057 {
1058 	/* Register subchannels which are already in use. */
1059 	cio_register_early_subchannels();
1060 	/* Start initial subchannel evaluation. */
1061 	css_schedule_eval_all();
1062 	css_complete_work();
1063 	return 0;
1064 }
1065 subsys_initcall_sync(channel_subsystem_init_sync);
1066 
1067 void channel_subsystem_reinit(void)
1068 {
1069 	struct channel_path *chp;
1070 	struct chp_id chpid;
1071 
1072 	chsc_enable_facility(CHSC_SDA_OC_MSS);
1073 	chp_id_for_each(&chpid) {
1074 		chp = chpid_to_chp(chpid);
1075 		if (chp)
1076 			chp_update_desc(chp);
1077 	}
1078 }
1079 
1080 #ifdef CONFIG_PROC_FS
1081 static ssize_t cio_settle_write(struct file *file, const char __user *buf,
1082 				size_t count, loff_t *ppos)
1083 {
1084 	int ret;
1085 
1086 	/* Handle pending CRW's. */
1087 	crw_wait_for_channel_report();
1088 	ret = css_complete_work();
1089 
1090 	return ret ? ret : count;
1091 }
1092 
1093 static const struct file_operations cio_settle_proc_fops = {
1094 	.open = nonseekable_open,
1095 	.write = cio_settle_write,
1096 	.llseek = no_llseek,
1097 };
1098 
1099 static int __init cio_settle_init(void)
1100 {
1101 	struct proc_dir_entry *entry;
1102 
1103 	entry = proc_create("cio_settle", S_IWUSR, NULL,
1104 			    &cio_settle_proc_fops);
1105 	if (!entry)
1106 		return -ENOMEM;
1107 	return 0;
1108 }
1109 device_initcall(cio_settle_init);
1110 #endif /*CONFIG_PROC_FS*/
1111 
1112 int sch_is_pseudo_sch(struct subchannel *sch)
1113 {
1114 	return sch == to_css(sch->dev.parent)->pseudo_subchannel;
1115 }
1116 
1117 static int css_bus_match(struct device *dev, struct device_driver *drv)
1118 {
1119 	struct subchannel *sch = to_subchannel(dev);
1120 	struct css_driver *driver = to_cssdriver(drv);
1121 	struct css_device_id *id;
1122 
1123 	for (id = driver->subchannel_type; id->match_flags; id++) {
1124 		if (sch->st == id->type)
1125 			return 1;
1126 	}
1127 
1128 	return 0;
1129 }
1130 
1131 static int css_probe(struct device *dev)
1132 {
1133 	struct subchannel *sch;
1134 	int ret;
1135 
1136 	sch = to_subchannel(dev);
1137 	sch->driver = to_cssdriver(dev->driver);
1138 	ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1139 	if (ret)
1140 		sch->driver = NULL;
1141 	return ret;
1142 }
1143 
1144 static int css_remove(struct device *dev)
1145 {
1146 	struct subchannel *sch;
1147 	int ret;
1148 
1149 	sch = to_subchannel(dev);
1150 	ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
1151 	sch->driver = NULL;
1152 	return ret;
1153 }
1154 
1155 static void css_shutdown(struct device *dev)
1156 {
1157 	struct subchannel *sch;
1158 
1159 	sch = to_subchannel(dev);
1160 	if (sch->driver && sch->driver->shutdown)
1161 		sch->driver->shutdown(sch);
1162 }
1163 
1164 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
1165 {
1166 	struct subchannel *sch = to_subchannel(dev);
1167 	int ret;
1168 
1169 	ret = add_uevent_var(env, "ST=%01X", sch->st);
1170 	if (ret)
1171 		return ret;
1172 	ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1173 	return ret;
1174 }
1175 
1176 static int css_pm_prepare(struct device *dev)
1177 {
1178 	struct subchannel *sch = to_subchannel(dev);
1179 	struct css_driver *drv;
1180 
1181 	if (mutex_is_locked(&sch->reg_mutex))
1182 		return -EAGAIN;
1183 	if (!sch->dev.driver)
1184 		return 0;
1185 	drv = to_cssdriver(sch->dev.driver);
1186 	/* Notify drivers that they may not register children. */
1187 	return drv->prepare ? drv->prepare(sch) : 0;
1188 }
1189 
1190 static void css_pm_complete(struct device *dev)
1191 {
1192 	struct subchannel *sch = to_subchannel(dev);
1193 	struct css_driver *drv;
1194 
1195 	if (!sch->dev.driver)
1196 		return;
1197 	drv = to_cssdriver(sch->dev.driver);
1198 	if (drv->complete)
1199 		drv->complete(sch);
1200 }
1201 
1202 static int css_pm_freeze(struct device *dev)
1203 {
1204 	struct subchannel *sch = to_subchannel(dev);
1205 	struct css_driver *drv;
1206 
1207 	if (!sch->dev.driver)
1208 		return 0;
1209 	drv = to_cssdriver(sch->dev.driver);
1210 	return drv->freeze ? drv->freeze(sch) : 0;
1211 }
1212 
1213 static int css_pm_thaw(struct device *dev)
1214 {
1215 	struct subchannel *sch = to_subchannel(dev);
1216 	struct css_driver *drv;
1217 
1218 	if (!sch->dev.driver)
1219 		return 0;
1220 	drv = to_cssdriver(sch->dev.driver);
1221 	return drv->thaw ? drv->thaw(sch) : 0;
1222 }
1223 
1224 static int css_pm_restore(struct device *dev)
1225 {
1226 	struct subchannel *sch = to_subchannel(dev);
1227 	struct css_driver *drv;
1228 
1229 	css_update_ssd_info(sch);
1230 	if (!sch->dev.driver)
1231 		return 0;
1232 	drv = to_cssdriver(sch->dev.driver);
1233 	return drv->restore ? drv->restore(sch) : 0;
1234 }
1235 
1236 static const struct dev_pm_ops css_pm_ops = {
1237 	.prepare = css_pm_prepare,
1238 	.complete = css_pm_complete,
1239 	.freeze = css_pm_freeze,
1240 	.thaw = css_pm_thaw,
1241 	.restore = css_pm_restore,
1242 };
1243 
1244 static struct bus_type css_bus_type = {
1245 	.name     = "css",
1246 	.match    = css_bus_match,
1247 	.probe    = css_probe,
1248 	.remove   = css_remove,
1249 	.shutdown = css_shutdown,
1250 	.uevent   = css_uevent,
1251 	.pm = &css_pm_ops,
1252 };
1253 
1254 /**
1255  * css_driver_register - register a css driver
1256  * @cdrv: css driver to register
1257  *
1258  * This is mainly a wrapper around driver_register that sets name
1259  * and bus_type in the embedded struct device_driver correctly.
1260  */
1261 int css_driver_register(struct css_driver *cdrv)
1262 {
1263 	cdrv->drv.bus = &css_bus_type;
1264 	return driver_register(&cdrv->drv);
1265 }
1266 EXPORT_SYMBOL_GPL(css_driver_register);
1267 
1268 /**
1269  * css_driver_unregister - unregister a css driver
1270  * @cdrv: css driver to unregister
1271  *
1272  * This is a wrapper around driver_unregister.
1273  */
1274 void css_driver_unregister(struct css_driver *cdrv)
1275 {
1276 	driver_unregister(&cdrv->drv);
1277 }
1278 EXPORT_SYMBOL_GPL(css_driver_unregister);
1279 
1280 MODULE_LICENSE("GPL");
1281