[S390] css_bus_type: make it static
[linux-3.10.git] / drivers / s390 / cio / css.c
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 struct subchannel *
141 css_alloc_subchannel(struct subchannel_id schid)
142 {
143         struct subchannel *sch;
144         int ret;
145
146         sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
147         if (sch == NULL)
148                 return ERR_PTR(-ENOMEM);
149         ret = cio_validate_subchannel (sch, schid);
150         if (ret < 0) {
151                 kfree(sch);
152                 return ERR_PTR(ret);
153         }
154         INIT_WORK(&sch->todo_work, css_sch_todo);
155         return sch;
156 }
157
158 static void
159 css_subchannel_release(struct device *dev)
160 {
161         struct subchannel *sch;
162
163         sch = to_subchannel(dev);
164         if (!cio_is_console(sch->schid)) {
165                 /* Reset intparm to zeroes. */
166                 sch->config.intparm = 0;
167                 cio_commit_config(sch);
168                 kfree(sch->lock);
169                 kfree(sch);
170         }
171 }
172
173 static int css_sch_device_register(struct subchannel *sch)
174 {
175         int ret;
176
177         mutex_lock(&sch->reg_mutex);
178         dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
179                      sch->schid.sch_no);
180         ret = device_register(&sch->dev);
181         mutex_unlock(&sch->reg_mutex);
182         return ret;
183 }
184
185 /**
186  * css_sch_device_unregister - unregister a subchannel
187  * @sch: subchannel to be unregistered
188  */
189 void css_sch_device_unregister(struct subchannel *sch)
190 {
191         mutex_lock(&sch->reg_mutex);
192         if (device_is_registered(&sch->dev))
193                 device_unregister(&sch->dev);
194         mutex_unlock(&sch->reg_mutex);
195 }
196 EXPORT_SYMBOL_GPL(css_sch_device_unregister);
197
198 static void css_sch_todo(struct work_struct *work)
199 {
200         struct subchannel *sch;
201         enum sch_todo todo;
202
203         sch = container_of(work, struct subchannel, todo_work);
204         /* Find out todo. */
205         spin_lock_irq(sch->lock);
206         todo = sch->todo;
207         CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,
208                       sch->schid.sch_no, todo);
209         sch->todo = SCH_TODO_NOTHING;
210         spin_unlock_irq(sch->lock);
211         /* Perform todo. */
212         if (todo == SCH_TODO_UNREG)
213                 css_sch_device_unregister(sch);
214         /* Release workqueue ref. */
215         put_device(&sch->dev);
216 }
217
218 /**
219  * css_sched_sch_todo - schedule a subchannel operation
220  * @sch: subchannel
221  * @todo: todo
222  *
223  * Schedule the operation identified by @todo to be performed on the slow path
224  * workqueue. Do nothing if another operation with higher priority is already
225  * scheduled. Needs to be called with subchannel lock held.
226  */
227 void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)
228 {
229         CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",
230                       sch->schid.ssid, sch->schid.sch_no, todo);
231         if (sch->todo >= todo)
232                 return;
233         /* Get workqueue ref. */
234         if (!get_device(&sch->dev))
235                 return;
236         sch->todo = todo;
237         if (!queue_work(cio_work_q, &sch->todo_work)) {
238                 /* Already queued, release workqueue ref. */
239                 put_device(&sch->dev);
240         }
241 }
242
243 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
244 {
245         int i;
246         int mask;
247
248         memset(ssd, 0, sizeof(struct chsc_ssd_info));
249         ssd->path_mask = pmcw->pim;
250         for (i = 0; i < 8; i++) {
251                 mask = 0x80 >> i;
252                 if (pmcw->pim & mask) {
253                         chp_id_init(&ssd->chpid[i]);
254                         ssd->chpid[i].id = pmcw->chpid[i];
255                 }
256         }
257 }
258
259 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
260 {
261         int i;
262         int mask;
263
264         for (i = 0; i < 8; i++) {
265                 mask = 0x80 >> i;
266                 if (ssd->path_mask & mask)
267                         if (!chp_is_registered(ssd->chpid[i]))
268                                 chp_new(ssd->chpid[i]);
269         }
270 }
271
272 void css_update_ssd_info(struct subchannel *sch)
273 {
274         int ret;
275
276         if (cio_is_console(sch->schid)) {
277                 /* Console is initialized too early for functions requiring
278                  * memory allocation. */
279                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
280         } else {
281                 ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
282                 if (ret)
283                         ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
284                 ssd_register_chpids(&sch->ssd_info);
285         }
286 }
287
288 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
289                          char *buf)
290 {
291         struct subchannel *sch = to_subchannel(dev);
292
293         return sprintf(buf, "%01x\n", sch->st);
294 }
295
296 static DEVICE_ATTR(type, 0444, type_show, NULL);
297
298 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
299                              char *buf)
300 {
301         struct subchannel *sch = to_subchannel(dev);
302
303         return sprintf(buf, "css:t%01X\n", sch->st);
304 }
305
306 static DEVICE_ATTR(modalias, 0444, modalias_show, NULL);
307
308 static struct attribute *subch_attrs[] = {
309         &dev_attr_type.attr,
310         &dev_attr_modalias.attr,
311         NULL,
312 };
313
314 static struct attribute_group subch_attr_group = {
315         .attrs = subch_attrs,
316 };
317
318 static const struct attribute_group *default_subch_attr_groups[] = {
319         &subch_attr_group,
320         NULL,
321 };
322
323 static int css_register_subchannel(struct subchannel *sch)
324 {
325         int ret;
326
327         /* Initialize the subchannel structure */
328         sch->dev.parent = &channel_subsystems[0]->device;
329         sch->dev.bus = &css_bus_type;
330         sch->dev.release = &css_subchannel_release;
331         sch->dev.groups = default_subch_attr_groups;
332         /*
333          * We don't want to generate uevents for I/O subchannels that don't
334          * have a working ccw device behind them since they will be
335          * unregistered before they can be used anyway, so we delay the add
336          * uevent until after device recognition was successful.
337          * Note that we suppress the uevent for all subchannel types;
338          * the subchannel driver can decide itself when it wants to inform
339          * userspace of its existence.
340          */
341         dev_set_uevent_suppress(&sch->dev, 1);
342         css_update_ssd_info(sch);
343         /* make it known to the system */
344         ret = css_sch_device_register(sch);
345         if (ret) {
346                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
347                               sch->schid.ssid, sch->schid.sch_no, ret);
348                 return ret;
349         }
350         if (!sch->driver) {
351                 /*
352                  * No driver matched. Generate the uevent now so that
353                  * a fitting driver module may be loaded based on the
354                  * modalias.
355                  */
356                 dev_set_uevent_suppress(&sch->dev, 0);
357                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
358         }
359         return ret;
360 }
361
362 int css_probe_device(struct subchannel_id schid)
363 {
364         int ret;
365         struct subchannel *sch;
366
367         if (cio_is_console(schid))
368                 sch = cio_get_console_subchannel();
369         else {
370                 sch = css_alloc_subchannel(schid);
371                 if (IS_ERR(sch))
372                         return PTR_ERR(sch);
373         }
374         ret = css_register_subchannel(sch);
375         if (ret) {
376                 if (!cio_is_console(schid))
377                         put_device(&sch->dev);
378         }
379         return ret;
380 }
381
382 static int
383 check_subchannel(struct device * dev, void * data)
384 {
385         struct subchannel *sch;
386         struct subchannel_id *schid = data;
387
388         sch = to_subchannel(dev);
389         return schid_equal(&sch->schid, schid);
390 }
391
392 struct subchannel *
393 get_subchannel_by_schid(struct subchannel_id schid)
394 {
395         struct device *dev;
396
397         dev = bus_find_device(&css_bus_type, NULL,
398                               &schid, check_subchannel);
399
400         return dev ? to_subchannel(dev) : NULL;
401 }
402
403 /**
404  * css_sch_is_valid() - check if a subchannel is valid
405  * @schib: subchannel information block for the subchannel
406  */
407 int css_sch_is_valid(struct schib *schib)
408 {
409         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
410                 return 0;
411         if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
412                 return 0;
413         return 1;
414 }
415 EXPORT_SYMBOL_GPL(css_sch_is_valid);
416
417 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
418 {
419         struct schib schib;
420
421         if (!slow) {
422                 /* Will be done on the slow path. */
423                 return -EAGAIN;
424         }
425         if (stsch_err(schid, &schib) || !css_sch_is_valid(&schib)) {
426                 /* Unusable - ignore. */
427                 return 0;
428         }
429         CIO_MSG_EVENT(4, "event: sch 0.%x.%04x, new\n", schid.ssid,
430                       schid.sch_no);
431
432         return css_probe_device(schid);
433 }
434
435 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
436 {
437         int ret = 0;
438
439         if (sch->driver) {
440                 if (sch->driver->sch_event)
441                         ret = sch->driver->sch_event(sch, slow);
442                 else
443                         dev_dbg(&sch->dev,
444                                 "Got subchannel machine check but "
445                                 "no sch_event handler provided.\n");
446         }
447         if (ret != 0 && ret != -EAGAIN) {
448                 CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
449                               sch->schid.ssid, sch->schid.sch_no, ret);
450         }
451         return ret;
452 }
453
454 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
455 {
456         struct subchannel *sch;
457         int ret;
458
459         sch = get_subchannel_by_schid(schid);
460         if (sch) {
461                 ret = css_evaluate_known_subchannel(sch, slow);
462                 put_device(&sch->dev);
463         } else
464                 ret = css_evaluate_new_subchannel(schid, slow);
465         if (ret == -EAGAIN)
466                 css_schedule_eval(schid);
467 }
468
469 static struct idset *slow_subchannel_set;
470 static spinlock_t slow_subchannel_lock;
471 static wait_queue_head_t css_eval_wq;
472 static atomic_t css_eval_scheduled;
473
474 static int __init slow_subchannel_init(void)
475 {
476         spin_lock_init(&slow_subchannel_lock);
477         atomic_set(&css_eval_scheduled, 0);
478         init_waitqueue_head(&css_eval_wq);
479         slow_subchannel_set = idset_sch_new();
480         if (!slow_subchannel_set) {
481                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
482                 return -ENOMEM;
483         }
484         return 0;
485 }
486
487 static int slow_eval_known_fn(struct subchannel *sch, void *data)
488 {
489         int eval;
490         int rc;
491
492         spin_lock_irq(&slow_subchannel_lock);
493         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
494         idset_sch_del(slow_subchannel_set, sch->schid);
495         spin_unlock_irq(&slow_subchannel_lock);
496         if (eval) {
497                 rc = css_evaluate_known_subchannel(sch, 1);
498                 if (rc == -EAGAIN)
499                         css_schedule_eval(sch->schid);
500         }
501         return 0;
502 }
503
504 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
505 {
506         int eval;
507         int rc = 0;
508
509         spin_lock_irq(&slow_subchannel_lock);
510         eval = idset_sch_contains(slow_subchannel_set, schid);
511         idset_sch_del(slow_subchannel_set, schid);
512         spin_unlock_irq(&slow_subchannel_lock);
513         if (eval) {
514                 rc = css_evaluate_new_subchannel(schid, 1);
515                 switch (rc) {
516                 case -EAGAIN:
517                         css_schedule_eval(schid);
518                         rc = 0;
519                         break;
520                 case -ENXIO:
521                 case -ENOMEM:
522                 case -EIO:
523                         /* These should abort looping */
524                         break;
525                 default:
526                         rc = 0;
527                 }
528         }
529         return rc;
530 }
531
532 static void css_slow_path_func(struct work_struct *unused)
533 {
534         unsigned long flags;
535
536         CIO_TRACE_EVENT(4, "slowpath");
537         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
538                                    NULL);
539         spin_lock_irqsave(&slow_subchannel_lock, flags);
540         if (idset_is_empty(slow_subchannel_set)) {
541                 atomic_set(&css_eval_scheduled, 0);
542                 wake_up(&css_eval_wq);
543         }
544         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
545 }
546
547 static DECLARE_WORK(slow_path_work, css_slow_path_func);
548 struct workqueue_struct *cio_work_q;
549
550 void css_schedule_eval(struct subchannel_id schid)
551 {
552         unsigned long flags;
553
554         spin_lock_irqsave(&slow_subchannel_lock, flags);
555         idset_sch_add(slow_subchannel_set, schid);
556         atomic_set(&css_eval_scheduled, 1);
557         queue_work(cio_work_q, &slow_path_work);
558         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
559 }
560
561 void css_schedule_eval_all(void)
562 {
563         unsigned long flags;
564
565         spin_lock_irqsave(&slow_subchannel_lock, flags);
566         idset_fill(slow_subchannel_set);
567         atomic_set(&css_eval_scheduled, 1);
568         queue_work(cio_work_q, &slow_path_work);
569         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
570 }
571
572 static int __unset_registered(struct device *dev, void *data)
573 {
574         struct idset *set = data;
575         struct subchannel *sch = to_subchannel(dev);
576
577         idset_sch_del(set, sch->schid);
578         return 0;
579 }
580
581 static void css_schedule_eval_all_unreg(void)
582 {
583         unsigned long flags;
584         struct idset *unreg_set;
585
586         /* Find unregistered subchannels. */
587         unreg_set = idset_sch_new();
588         if (!unreg_set) {
589                 /* Fallback. */
590                 css_schedule_eval_all();
591                 return;
592         }
593         idset_fill(unreg_set);
594         bus_for_each_dev(&css_bus_type, NULL, unreg_set, __unset_registered);
595         /* Apply to slow_subchannel_set. */
596         spin_lock_irqsave(&slow_subchannel_lock, flags);
597         idset_add_set(slow_subchannel_set, unreg_set);
598         atomic_set(&css_eval_scheduled, 1);
599         queue_work(cio_work_q, &slow_path_work);
600         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
601         idset_free(unreg_set);
602 }
603
604 void css_wait_for_slow_path(void)
605 {
606         flush_workqueue(cio_work_q);
607 }
608
609 /* Schedule reprobing of all unregistered subchannels. */
610 void css_schedule_reprobe(void)
611 {
612         css_schedule_eval_all_unreg();
613 }
614 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
615
616 /*
617  * Called from the machine check handler for subchannel report words.
618  */
619 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
620 {
621         struct subchannel_id mchk_schid;
622         struct subchannel *sch;
623
624         if (overflow) {
625                 css_schedule_eval_all();
626                 return;
627         }
628         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
629                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
630                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
631                       crw0->erc, crw0->rsid);
632         if (crw1)
633                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
634                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
635                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
636                               crw1->anc, crw1->erc, crw1->rsid);
637         init_subchannel_id(&mchk_schid);
638         mchk_schid.sch_no = crw0->rsid;
639         if (crw1)
640                 mchk_schid.ssid = (crw1->rsid >> 4) & 3;
641
642         if (crw0->erc == CRW_ERC_PMOD) {
643                 sch = get_subchannel_by_schid(mchk_schid);
644                 if (sch) {
645                         css_update_ssd_info(sch);
646                         put_device(&sch->dev);
647                 }
648         }
649         /*
650          * Since we are always presented with IPI in the CRW, we have to
651          * use stsch() to find out if the subchannel in question has come
652          * or gone.
653          */
654         css_evaluate_subchannel(mchk_schid, 0);
655 }
656
657 static void __init
658 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
659 {
660         struct cpuid cpu_id;
661
662         if (css_general_characteristics.mcss) {
663                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
664                 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
665         } else {
666 #ifdef CONFIG_SMP
667                 css->global_pgid.pgid_high.cpu_addr = stap();
668 #else
669                 css->global_pgid.pgid_high.cpu_addr = 0;
670 #endif
671         }
672         get_cpu_id(&cpu_id);
673         css->global_pgid.cpu_id = cpu_id.ident;
674         css->global_pgid.cpu_model = cpu_id.machine;
675         css->global_pgid.tod_high = tod_high;
676
677 }
678
679 static void
680 channel_subsystem_release(struct device *dev)
681 {
682         struct channel_subsystem *css;
683
684         css = to_css(dev);
685         mutex_destroy(&css->mutex);
686         if (css->pseudo_subchannel) {
687                 /* Implies that it has been generated but never registered. */
688                 css_subchannel_release(&css->pseudo_subchannel->dev);
689                 css->pseudo_subchannel = NULL;
690         }
691         kfree(css);
692 }
693
694 static ssize_t
695 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
696                    char *buf)
697 {
698         struct channel_subsystem *css = to_css(dev);
699         int ret;
700
701         if (!css)
702                 return 0;
703         mutex_lock(&css->mutex);
704         ret = sprintf(buf, "%x\n", css->cm_enabled);
705         mutex_unlock(&css->mutex);
706         return ret;
707 }
708
709 static ssize_t
710 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
711                     const char *buf, size_t count)
712 {
713         struct channel_subsystem *css = to_css(dev);
714         int ret;
715         unsigned long val;
716
717         ret = strict_strtoul(buf, 16, &val);
718         if (ret)
719                 return ret;
720         mutex_lock(&css->mutex);
721         switch (val) {
722         case 0:
723                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
724                 break;
725         case 1:
726                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
727                 break;
728         default:
729                 ret = -EINVAL;
730         }
731         mutex_unlock(&css->mutex);
732         return ret < 0 ? ret : count;
733 }
734
735 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
736
737 static int __init setup_css(int nr)
738 {
739         u32 tod_high;
740         int ret;
741         struct channel_subsystem *css;
742
743         css = channel_subsystems[nr];
744         memset(css, 0, sizeof(struct channel_subsystem));
745         css->pseudo_subchannel =
746                 kzalloc(sizeof(*css->pseudo_subchannel), GFP_KERNEL);
747         if (!css->pseudo_subchannel)
748                 return -ENOMEM;
749         css->pseudo_subchannel->dev.parent = &css->device;
750         css->pseudo_subchannel->dev.release = css_subchannel_release;
751         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
752         mutex_init(&css->pseudo_subchannel->reg_mutex);
753         ret = cio_create_sch_lock(css->pseudo_subchannel);
754         if (ret) {
755                 kfree(css->pseudo_subchannel);
756                 return ret;
757         }
758         mutex_init(&css->mutex);
759         css->valid = 1;
760         css->cssid = nr;
761         dev_set_name(&css->device, "css%x", nr);
762         css->device.release = channel_subsystem_release;
763         tod_high = (u32) (get_clock() >> 32);
764         css_generate_pgid(css, tod_high);
765         return 0;
766 }
767
768 static int css_reboot_event(struct notifier_block *this,
769                             unsigned long event,
770                             void *ptr)
771 {
772         int ret, i;
773
774         ret = NOTIFY_DONE;
775         for (i = 0; i <= __MAX_CSSID; i++) {
776                 struct channel_subsystem *css;
777
778                 css = channel_subsystems[i];
779                 mutex_lock(&css->mutex);
780                 if (css->cm_enabled)
781                         if (chsc_secm(css, 0))
782                                 ret = NOTIFY_BAD;
783                 mutex_unlock(&css->mutex);
784         }
785
786         return ret;
787 }
788
789 static struct notifier_block css_reboot_notifier = {
790         .notifier_call = css_reboot_event,
791 };
792
793 /*
794  * Since the css devices are neither on a bus nor have a class
795  * nor have a special device type, we cannot stop/restart channel
796  * path measurements via the normal suspend/resume callbacks, but have
797  * to use notifiers.
798  */
799 static int css_power_event(struct notifier_block *this, unsigned long event,
800                            void *ptr)
801 {
802         int ret, i;
803
804         switch (event) {
805         case PM_HIBERNATION_PREPARE:
806         case PM_SUSPEND_PREPARE:
807                 ret = NOTIFY_DONE;
808                 for (i = 0; i <= __MAX_CSSID; i++) {
809                         struct channel_subsystem *css;
810
811                         css = channel_subsystems[i];
812                         mutex_lock(&css->mutex);
813                         if (!css->cm_enabled) {
814                                 mutex_unlock(&css->mutex);
815                                 continue;
816                         }
817                         if (__chsc_do_secm(css, 0))
818                                 ret = NOTIFY_BAD;
819                         mutex_unlock(&css->mutex);
820                 }
821                 break;
822         case PM_POST_HIBERNATION:
823         case PM_POST_SUSPEND:
824                 ret = NOTIFY_DONE;
825                 for (i = 0; i <= __MAX_CSSID; i++) {
826                         struct channel_subsystem *css;
827
828                         css = channel_subsystems[i];
829                         mutex_lock(&css->mutex);
830                         if (!css->cm_enabled) {
831                                 mutex_unlock(&css->mutex);
832                                 continue;
833                         }
834                         if (__chsc_do_secm(css, 1))
835                                 ret = NOTIFY_BAD;
836                         mutex_unlock(&css->mutex);
837                 }
838                 /* search for subchannels, which appeared during hibernation */
839                 css_schedule_reprobe();
840                 break;
841         default:
842                 ret = NOTIFY_DONE;
843         }
844         return ret;
845
846 }
847 static struct notifier_block css_power_notifier = {
848         .notifier_call = css_power_event,
849 };
850
851 /*
852  * Now that the driver core is running, we can setup our channel subsystem.
853  * The struct subchannel's are created during probing (except for the
854  * static console subchannel).
855  */
856 static int __init css_bus_init(void)
857 {
858         int ret, i;
859
860         ret = chsc_init();
861         if (ret)
862                 return ret;
863
864         chsc_determine_css_characteristics();
865         /* Try to enable MSS. */
866         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
867         if (ret)
868                 max_ssid = 0;
869         else /* Success. */
870                 max_ssid = __MAX_SSID;
871
872         ret = slow_subchannel_init();
873         if (ret)
874                 goto out;
875
876         ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
877         if (ret)
878                 goto out;
879
880         if ((ret = bus_register(&css_bus_type)))
881                 goto out;
882
883         /* Setup css structure. */
884         for (i = 0; i <= __MAX_CSSID; i++) {
885                 struct channel_subsystem *css;
886
887                 css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
888                 if (!css) {
889                         ret = -ENOMEM;
890                         goto out_unregister;
891                 }
892                 channel_subsystems[i] = css;
893                 ret = setup_css(i);
894                 if (ret) {
895                         kfree(channel_subsystems[i]);
896                         goto out_unregister;
897                 }
898                 ret = device_register(&css->device);
899                 if (ret) {
900                         put_device(&css->device);
901                         goto out_unregister;
902                 }
903                 if (css_chsc_characteristics.secm) {
904                         ret = device_create_file(&css->device,
905                                                  &dev_attr_cm_enable);
906                         if (ret)
907                                 goto out_device;
908                 }
909                 ret = device_register(&css->pseudo_subchannel->dev);
910                 if (ret) {
911                         put_device(&css->pseudo_subchannel->dev);
912                         goto out_file;
913                 }
914         }
915         ret = register_reboot_notifier(&css_reboot_notifier);
916         if (ret)
917                 goto out_unregister;
918         ret = register_pm_notifier(&css_power_notifier);
919         if (ret) {
920                 unregister_reboot_notifier(&css_reboot_notifier);
921                 goto out_unregister;
922         }
923         css_init_done = 1;
924
925         /* Enable default isc for I/O subchannels. */
926         isc_register(IO_SCH_ISC);
927
928         return 0;
929 out_file:
930         if (css_chsc_characteristics.secm)
931                 device_remove_file(&channel_subsystems[i]->device,
932                                    &dev_attr_cm_enable);
933 out_device:
934         device_unregister(&channel_subsystems[i]->device);
935 out_unregister:
936         while (i > 0) {
937                 struct channel_subsystem *css;
938
939                 i--;
940                 css = channel_subsystems[i];
941                 device_unregister(&css->pseudo_subchannel->dev);
942                 css->pseudo_subchannel = NULL;
943                 if (css_chsc_characteristics.secm)
944                         device_remove_file(&css->device,
945                                            &dev_attr_cm_enable);
946                 device_unregister(&css->device);
947         }
948         bus_unregister(&css_bus_type);
949 out:
950         crw_unregister_handler(CRW_RSC_SCH);
951         idset_free(slow_subchannel_set);
952         chsc_init_cleanup();
953         pr_alert("The CSS device driver initialization failed with "
954                  "errno=%d\n", ret);
955         return ret;
956 }
957
958 static void __init css_bus_cleanup(void)
959 {
960         struct channel_subsystem *css;
961         int i;
962
963         for (i = 0; i <= __MAX_CSSID; i++) {
964                 css = channel_subsystems[i];
965                 device_unregister(&css->pseudo_subchannel->dev);
966                 css->pseudo_subchannel = NULL;
967                 if (css_chsc_characteristics.secm)
968                         device_remove_file(&css->device, &dev_attr_cm_enable);
969                 device_unregister(&css->device);
970         }
971         bus_unregister(&css_bus_type);
972         crw_unregister_handler(CRW_RSC_SCH);
973         idset_free(slow_subchannel_set);
974         chsc_init_cleanup();
975         isc_unregister(IO_SCH_ISC);
976 }
977
978 static int __init channel_subsystem_init(void)
979 {
980         int ret;
981
982         ret = css_bus_init();
983         if (ret)
984                 return ret;
985         cio_work_q = create_singlethread_workqueue("cio");
986         if (!cio_work_q) {
987                 ret = -ENOMEM;
988                 goto out_bus;
989         }
990         ret = io_subchannel_init();
991         if (ret)
992                 goto out_wq;
993
994         return ret;
995 out_wq:
996         destroy_workqueue(cio_work_q);
997 out_bus:
998         css_bus_cleanup();
999         return ret;
1000 }
1001 subsys_initcall(channel_subsystem_init);
1002
1003 static int css_settle(struct device_driver *drv, void *unused)
1004 {
1005         struct css_driver *cssdrv = to_cssdriver(drv);
1006
1007         if (cssdrv->settle)
1008                 return cssdrv->settle();
1009         return 0;
1010 }
1011
1012 int css_complete_work(void)
1013 {
1014         int ret;
1015
1016         /* Wait for the evaluation of subchannels to finish. */
1017         ret = wait_event_interruptible(css_eval_wq,
1018                                        atomic_read(&css_eval_scheduled) == 0);
1019         if (ret)
1020                 return -EINTR;
1021         flush_workqueue(cio_work_q);
1022         /* Wait for the subchannel type specific initialization to finish */
1023         return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
1024 }
1025
1026
1027 /*
1028  * Wait for the initialization of devices to finish, to make sure we are
1029  * done with our setup if the search for the root device starts.
1030  */
1031 static int __init channel_subsystem_init_sync(void)
1032 {
1033         /* Start initial subchannel evaluation. */
1034         css_schedule_eval_all();
1035         css_complete_work();
1036         return 0;
1037 }
1038 subsys_initcall_sync(channel_subsystem_init_sync);
1039
1040 void channel_subsystem_reinit(void)
1041 {
1042         struct channel_path *chp;
1043         struct chp_id chpid;
1044
1045         chsc_enable_facility(CHSC_SDA_OC_MSS);
1046         chp_id_for_each(&chpid) {
1047                 chp = chpid_to_chp(chpid);
1048                 if (!chp)
1049                         continue;
1050                 chsc_determine_base_channel_path_desc(chpid, &chp->desc);
1051         }
1052 }
1053
1054 #ifdef CONFIG_PROC_FS
1055 static ssize_t cio_settle_write(struct file *file, const char __user *buf,
1056                                 size_t count, loff_t *ppos)
1057 {
1058         int ret;
1059
1060         /* Handle pending CRW's. */
1061         crw_wait_for_channel_report();
1062         ret = css_complete_work();
1063
1064         return ret ? ret : count;
1065 }
1066
1067 static const struct file_operations cio_settle_proc_fops = {
1068         .open = nonseekable_open,
1069         .write = cio_settle_write,
1070         .llseek = no_llseek,
1071 };
1072
1073 static int __init cio_settle_init(void)
1074 {
1075         struct proc_dir_entry *entry;
1076
1077         entry = proc_create("cio_settle", S_IWUSR, NULL,
1078                             &cio_settle_proc_fops);
1079         if (!entry)
1080                 return -ENOMEM;
1081         return 0;
1082 }
1083 device_initcall(cio_settle_init);
1084 #endif /*CONFIG_PROC_FS*/
1085
1086 int sch_is_pseudo_sch(struct subchannel *sch)
1087 {
1088         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
1089 }
1090
1091 static int css_bus_match(struct device *dev, struct device_driver *drv)
1092 {
1093         struct subchannel *sch = to_subchannel(dev);
1094         struct css_driver *driver = to_cssdriver(drv);
1095         struct css_device_id *id;
1096
1097         for (id = driver->subchannel_type; id->match_flags; id++) {
1098                 if (sch->st == id->type)
1099                         return 1;
1100         }
1101
1102         return 0;
1103 }
1104
1105 static int css_probe(struct device *dev)
1106 {
1107         struct subchannel *sch;
1108         int ret;
1109
1110         sch = to_subchannel(dev);
1111         sch->driver = to_cssdriver(dev->driver);
1112         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1113         if (ret)
1114                 sch->driver = NULL;
1115         return ret;
1116 }
1117
1118 static int css_remove(struct device *dev)
1119 {
1120         struct subchannel *sch;
1121         int ret;
1122
1123         sch = to_subchannel(dev);
1124         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
1125         sch->driver = NULL;
1126         return ret;
1127 }
1128
1129 static void css_shutdown(struct device *dev)
1130 {
1131         struct subchannel *sch;
1132
1133         sch = to_subchannel(dev);
1134         if (sch->driver && sch->driver->shutdown)
1135                 sch->driver->shutdown(sch);
1136 }
1137
1138 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
1139 {
1140         struct subchannel *sch = to_subchannel(dev);
1141         int ret;
1142
1143         ret = add_uevent_var(env, "ST=%01X", sch->st);
1144         if (ret)
1145                 return ret;
1146         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1147         return ret;
1148 }
1149
1150 static int css_pm_prepare(struct device *dev)
1151 {
1152         struct subchannel *sch = to_subchannel(dev);
1153         struct css_driver *drv;
1154
1155         if (mutex_is_locked(&sch->reg_mutex))
1156                 return -EAGAIN;
1157         if (!sch->dev.driver)
1158                 return 0;
1159         drv = to_cssdriver(sch->dev.driver);
1160         /* Notify drivers that they may not register children. */
1161         return drv->prepare ? drv->prepare(sch) : 0;
1162 }
1163
1164 static void css_pm_complete(struct device *dev)
1165 {
1166         struct subchannel *sch = to_subchannel(dev);
1167         struct css_driver *drv;
1168
1169         if (!sch->dev.driver)
1170                 return;
1171         drv = to_cssdriver(sch->dev.driver);
1172         if (drv->complete)
1173                 drv->complete(sch);
1174 }
1175
1176 static int css_pm_freeze(struct device *dev)
1177 {
1178         struct subchannel *sch = to_subchannel(dev);
1179         struct css_driver *drv;
1180
1181         if (!sch->dev.driver)
1182                 return 0;
1183         drv = to_cssdriver(sch->dev.driver);
1184         return drv->freeze ? drv->freeze(sch) : 0;
1185 }
1186
1187 static int css_pm_thaw(struct device *dev)
1188 {
1189         struct subchannel *sch = to_subchannel(dev);
1190         struct css_driver *drv;
1191
1192         if (!sch->dev.driver)
1193                 return 0;
1194         drv = to_cssdriver(sch->dev.driver);
1195         return drv->thaw ? drv->thaw(sch) : 0;
1196 }
1197
1198 static int css_pm_restore(struct device *dev)
1199 {
1200         struct subchannel *sch = to_subchannel(dev);
1201         struct css_driver *drv;
1202
1203         css_update_ssd_info(sch);
1204         if (!sch->dev.driver)
1205                 return 0;
1206         drv = to_cssdriver(sch->dev.driver);
1207         return drv->restore ? drv->restore(sch) : 0;
1208 }
1209
1210 static const struct dev_pm_ops css_pm_ops = {
1211         .prepare = css_pm_prepare,
1212         .complete = css_pm_complete,
1213         .freeze = css_pm_freeze,
1214         .thaw = css_pm_thaw,
1215         .restore = css_pm_restore,
1216 };
1217
1218 static struct bus_type css_bus_type = {
1219         .name     = "css",
1220         .match    = css_bus_match,
1221         .probe    = css_probe,
1222         .remove   = css_remove,
1223         .shutdown = css_shutdown,
1224         .uevent   = css_uevent,
1225         .pm = &css_pm_ops,
1226 };
1227
1228 /**
1229  * css_driver_register - register a css driver
1230  * @cdrv: css driver to register
1231  *
1232  * This is mainly a wrapper around driver_register that sets name
1233  * and bus_type in the embedded struct device_driver correctly.
1234  */
1235 int css_driver_register(struct css_driver *cdrv)
1236 {
1237         cdrv->drv.bus = &css_bus_type;
1238         return driver_register(&cdrv->drv);
1239 }
1240 EXPORT_SYMBOL_GPL(css_driver_register);
1241
1242 /**
1243  * css_driver_unregister - unregister a css driver
1244  * @cdrv: css driver to unregister
1245  *
1246  * This is a wrapper around driver_unregister.
1247  */
1248 void css_driver_unregister(struct css_driver *cdrv)
1249 {
1250         driver_unregister(&cdrv->drv);
1251 }
1252 EXPORT_SYMBOL_GPL(css_driver_unregister);
1253
1254 MODULE_LICENSE("GPL");