Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6] / drivers / s390 / cio / css.c
1 /*
2  *  drivers/s390/cio/css.c
3  *  driver for channel subsystem
4  *
5  *    Copyright IBM Corp. 2002,2008
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 <asm/isc.h>
21 #include <asm/crw.h>
22
23 #include "css.h"
24 #include "cio.h"
25 #include "cio_debug.h"
26 #include "ioasm.h"
27 #include "chsc.h"
28 #include "device.h"
29 #include "idset.h"
30 #include "chp.h"
31
32 int css_init_done = 0;
33 static int need_reprobe = 0;
34 static int max_ssid = 0;
35
36 struct channel_subsystem *channel_subsystems[__MAX_CSSID + 1];
37
38 int
39 for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
40 {
41         struct subchannel_id schid;
42         int ret;
43
44         init_subchannel_id(&schid);
45         ret = -ENODEV;
46         do {
47                 do {
48                         ret = fn(schid, data);
49                         if (ret)
50                                 break;
51                 } while (schid.sch_no++ < __MAX_SUBCHANNEL);
52                 schid.sch_no = 0;
53         } while (schid.ssid++ < max_ssid);
54         return ret;
55 }
56
57 struct cb_data {
58         void *data;
59         struct idset *set;
60         int (*fn_known_sch)(struct subchannel *, void *);
61         int (*fn_unknown_sch)(struct subchannel_id, void *);
62 };
63
64 static int call_fn_known_sch(struct device *dev, void *data)
65 {
66         struct subchannel *sch = to_subchannel(dev);
67         struct cb_data *cb = data;
68         int rc = 0;
69
70         idset_sch_del(cb->set, sch->schid);
71         if (cb->fn_known_sch)
72                 rc = cb->fn_known_sch(sch, cb->data);
73         return rc;
74 }
75
76 static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
77 {
78         struct cb_data *cb = data;
79         int rc = 0;
80
81         if (idset_sch_contains(cb->set, schid))
82                 rc = cb->fn_unknown_sch(schid, cb->data);
83         return rc;
84 }
85
86 static int call_fn_all_sch(struct subchannel_id schid, void *data)
87 {
88         struct cb_data *cb = data;
89         struct subchannel *sch;
90         int rc = 0;
91
92         sch = get_subchannel_by_schid(schid);
93         if (sch) {
94                 if (cb->fn_known_sch)
95                         rc = cb->fn_known_sch(sch, cb->data);
96                 put_device(&sch->dev);
97         } else {
98                 if (cb->fn_unknown_sch)
99                         rc = cb->fn_unknown_sch(schid, cb->data);
100         }
101
102         return rc;
103 }
104
105 int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
106                                int (*fn_unknown)(struct subchannel_id,
107                                void *), void *data)
108 {
109         struct cb_data cb;
110         int rc;
111
112         cb.data = data;
113         cb.fn_known_sch = fn_known;
114         cb.fn_unknown_sch = fn_unknown;
115
116         cb.set = idset_sch_new();
117         if (!cb.set)
118                 /* fall back to brute force scanning in case of oom */
119                 return for_each_subchannel(call_fn_all_sch, &cb);
120
121         idset_fill(cb.set);
122
123         /* Process registered subchannels. */
124         rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
125         if (rc)
126                 goto out;
127         /* Process unregistered subchannels. */
128         if (fn_unknown)
129                 rc = for_each_subchannel(call_fn_unknown_sch, &cb);
130 out:
131         idset_free(cb.set);
132
133         return rc;
134 }
135
136 static struct subchannel *
137 css_alloc_subchannel(struct subchannel_id schid)
138 {
139         struct subchannel *sch;
140         int ret;
141
142         sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
143         if (sch == NULL)
144                 return ERR_PTR(-ENOMEM);
145         ret = cio_validate_subchannel (sch, schid);
146         if (ret < 0) {
147                 kfree(sch);
148                 return ERR_PTR(ret);
149         }
150         return sch;
151 }
152
153 static void
154 css_free_subchannel(struct subchannel *sch)
155 {
156         if (sch) {
157                 /* Reset intparm to zeroes. */
158                 sch->config.intparm = 0;
159                 cio_commit_config(sch);
160                 kfree(sch->lock);
161                 kfree(sch);
162         }
163 }
164
165 static void
166 css_subchannel_release(struct device *dev)
167 {
168         struct subchannel *sch;
169
170         sch = to_subchannel(dev);
171         if (!cio_is_console(sch->schid)) {
172                 kfree(sch->lock);
173                 kfree(sch);
174         }
175 }
176
177 static int css_sch_device_register(struct subchannel *sch)
178 {
179         int ret;
180
181         mutex_lock(&sch->reg_mutex);
182         ret = device_register(&sch->dev);
183         mutex_unlock(&sch->reg_mutex);
184         return ret;
185 }
186
187 /**
188  * css_sch_device_unregister - unregister a subchannel
189  * @sch: subchannel to be unregistered
190  */
191 void css_sch_device_unregister(struct subchannel *sch)
192 {
193         mutex_lock(&sch->reg_mutex);
194         if (device_is_registered(&sch->dev))
195                 device_unregister(&sch->dev);
196         mutex_unlock(&sch->reg_mutex);
197 }
198 EXPORT_SYMBOL_GPL(css_sch_device_unregister);
199
200 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
201 {
202         int i;
203         int mask;
204
205         memset(ssd, 0, sizeof(struct chsc_ssd_info));
206         ssd->path_mask = pmcw->pim;
207         for (i = 0; i < 8; i++) {
208                 mask = 0x80 >> i;
209                 if (pmcw->pim & mask) {
210                         chp_id_init(&ssd->chpid[i]);
211                         ssd->chpid[i].id = pmcw->chpid[i];
212                 }
213         }
214 }
215
216 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
217 {
218         int i;
219         int mask;
220
221         for (i = 0; i < 8; i++) {
222                 mask = 0x80 >> i;
223                 if (ssd->path_mask & mask)
224                         if (!chp_is_registered(ssd->chpid[i]))
225                                 chp_new(ssd->chpid[i]);
226         }
227 }
228
229 void css_update_ssd_info(struct subchannel *sch)
230 {
231         int ret;
232
233         if (cio_is_console(sch->schid)) {
234                 /* Console is initialized too early for functions requiring
235                  * memory allocation. */
236                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
237         } else {
238                 ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
239                 if (ret)
240                         ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
241                 ssd_register_chpids(&sch->ssd_info);
242         }
243 }
244
245 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
246                          char *buf)
247 {
248         struct subchannel *sch = to_subchannel(dev);
249
250         return sprintf(buf, "%01x\n", sch->st);
251 }
252
253 static DEVICE_ATTR(type, 0444, type_show, NULL);
254
255 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
256                              char *buf)
257 {
258         struct subchannel *sch = to_subchannel(dev);
259
260         return sprintf(buf, "css:t%01X\n", sch->st);
261 }
262
263 static DEVICE_ATTR(modalias, 0444, modalias_show, NULL);
264
265 static struct attribute *subch_attrs[] = {
266         &dev_attr_type.attr,
267         &dev_attr_modalias.attr,
268         NULL,
269 };
270
271 static struct attribute_group subch_attr_group = {
272         .attrs = subch_attrs,
273 };
274
275 static struct attribute_group *default_subch_attr_groups[] = {
276         &subch_attr_group,
277         NULL,
278 };
279
280 static int css_register_subchannel(struct subchannel *sch)
281 {
282         int ret;
283
284         /* Initialize the subchannel structure */
285         sch->dev.parent = &channel_subsystems[0]->device;
286         sch->dev.bus = &css_bus_type;
287         sch->dev.release = &css_subchannel_release;
288         sch->dev.groups = default_subch_attr_groups;
289         /*
290          * We don't want to generate uevents for I/O subchannels that don't
291          * have a working ccw device behind them since they will be
292          * unregistered before they can be used anyway, so we delay the add
293          * uevent until after device recognition was successful.
294          * Note that we suppress the uevent for all subchannel types;
295          * the subchannel driver can decide itself when it wants to inform
296          * userspace of its existence.
297          */
298         dev_set_uevent_suppress(&sch->dev, 1);
299         css_update_ssd_info(sch);
300         /* make it known to the system */
301         ret = css_sch_device_register(sch);
302         if (ret) {
303                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
304                               sch->schid.ssid, sch->schid.sch_no, ret);
305                 return ret;
306         }
307         if (!sch->driver) {
308                 /*
309                  * No driver matched. Generate the uevent now so that
310                  * a fitting driver module may be loaded based on the
311                  * modalias.
312                  */
313                 dev_set_uevent_suppress(&sch->dev, 0);
314                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
315         }
316         return ret;
317 }
318
319 int css_probe_device(struct subchannel_id schid)
320 {
321         int ret;
322         struct subchannel *sch;
323
324         sch = css_alloc_subchannel(schid);
325         if (IS_ERR(sch))
326                 return PTR_ERR(sch);
327         ret = css_register_subchannel(sch);
328         if (ret)
329                 css_free_subchannel(sch);
330         return ret;
331 }
332
333 static int
334 check_subchannel(struct device * dev, void * data)
335 {
336         struct subchannel *sch;
337         struct subchannel_id *schid = data;
338
339         sch = to_subchannel(dev);
340         return schid_equal(&sch->schid, schid);
341 }
342
343 struct subchannel *
344 get_subchannel_by_schid(struct subchannel_id schid)
345 {
346         struct device *dev;
347
348         dev = bus_find_device(&css_bus_type, NULL,
349                               &schid, check_subchannel);
350
351         return dev ? to_subchannel(dev) : NULL;
352 }
353
354 /**
355  * css_sch_is_valid() - check if a subchannel is valid
356  * @schib: subchannel information block for the subchannel
357  */
358 int css_sch_is_valid(struct schib *schib)
359 {
360         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
361                 return 0;
362         if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
363                 return 0;
364         return 1;
365 }
366 EXPORT_SYMBOL_GPL(css_sch_is_valid);
367
368 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
369 {
370         struct schib schib;
371
372         if (!slow) {
373                 /* Will be done on the slow path. */
374                 return -EAGAIN;
375         }
376         if (stsch_err(schid, &schib) || !css_sch_is_valid(&schib)) {
377                 /* Unusable - ignore. */
378                 return 0;
379         }
380         CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, unknown, "
381                          "slow path.\n", schid.ssid, schid.sch_no, CIO_OPER);
382
383         return css_probe_device(schid);
384 }
385
386 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
387 {
388         int ret = 0;
389
390         if (sch->driver) {
391                 if (sch->driver->sch_event)
392                         ret = sch->driver->sch_event(sch, slow);
393                 else
394                         dev_dbg(&sch->dev,
395                                 "Got subchannel machine check but "
396                                 "no sch_event handler provided.\n");
397         }
398         return ret;
399 }
400
401 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
402 {
403         struct subchannel *sch;
404         int ret;
405
406         sch = get_subchannel_by_schid(schid);
407         if (sch) {
408                 ret = css_evaluate_known_subchannel(sch, slow);
409                 put_device(&sch->dev);
410         } else
411                 ret = css_evaluate_new_subchannel(schid, slow);
412         if (ret == -EAGAIN)
413                 css_schedule_eval(schid);
414 }
415
416 static struct idset *slow_subchannel_set;
417 static spinlock_t slow_subchannel_lock;
418
419 static int __init slow_subchannel_init(void)
420 {
421         spin_lock_init(&slow_subchannel_lock);
422         slow_subchannel_set = idset_sch_new();
423         if (!slow_subchannel_set) {
424                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
425                 return -ENOMEM;
426         }
427         return 0;
428 }
429
430 static int slow_eval_known_fn(struct subchannel *sch, void *data)
431 {
432         int eval;
433         int rc;
434
435         spin_lock_irq(&slow_subchannel_lock);
436         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
437         idset_sch_del(slow_subchannel_set, sch->schid);
438         spin_unlock_irq(&slow_subchannel_lock);
439         if (eval) {
440                 rc = css_evaluate_known_subchannel(sch, 1);
441                 if (rc == -EAGAIN)
442                         css_schedule_eval(sch->schid);
443         }
444         return 0;
445 }
446
447 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
448 {
449         int eval;
450         int rc = 0;
451
452         spin_lock_irq(&slow_subchannel_lock);
453         eval = idset_sch_contains(slow_subchannel_set, schid);
454         idset_sch_del(slow_subchannel_set, schid);
455         spin_unlock_irq(&slow_subchannel_lock);
456         if (eval) {
457                 rc = css_evaluate_new_subchannel(schid, 1);
458                 switch (rc) {
459                 case -EAGAIN:
460                         css_schedule_eval(schid);
461                         rc = 0;
462                         break;
463                 case -ENXIO:
464                 case -ENOMEM:
465                 case -EIO:
466                         /* These should abort looping */
467                         break;
468                 default:
469                         rc = 0;
470                 }
471         }
472         return rc;
473 }
474
475 static void css_slow_path_func(struct work_struct *unused)
476 {
477         CIO_TRACE_EVENT(4, "slowpath");
478         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
479                                    NULL);
480 }
481
482 static DECLARE_WORK(slow_path_work, css_slow_path_func);
483 struct workqueue_struct *slow_path_wq;
484
485 void css_schedule_eval(struct subchannel_id schid)
486 {
487         unsigned long flags;
488
489         spin_lock_irqsave(&slow_subchannel_lock, flags);
490         idset_sch_add(slow_subchannel_set, schid);
491         queue_work(slow_path_wq, &slow_path_work);
492         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
493 }
494
495 void css_schedule_eval_all(void)
496 {
497         unsigned long flags;
498
499         spin_lock_irqsave(&slow_subchannel_lock, flags);
500         idset_fill(slow_subchannel_set);
501         queue_work(slow_path_wq, &slow_path_work);
502         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
503 }
504
505 void css_wait_for_slow_path(void)
506 {
507         flush_workqueue(slow_path_wq);
508 }
509
510 /* Reprobe subchannel if unregistered. */
511 static int reprobe_subchannel(struct subchannel_id schid, void *data)
512 {
513         int ret;
514
515         CIO_MSG_EVENT(6, "cio: reprobe 0.%x.%04x\n",
516                       schid.ssid, schid.sch_no);
517         if (need_reprobe)
518                 return -EAGAIN;
519
520         ret = css_probe_device(schid);
521         switch (ret) {
522         case 0:
523                 break;
524         case -ENXIO:
525         case -ENOMEM:
526         case -EIO:
527                 /* These should abort looping */
528                 break;
529         default:
530                 ret = 0;
531         }
532
533         return ret;
534 }
535
536 static void reprobe_after_idle(struct work_struct *unused)
537 {
538         /* Make sure initial subchannel scan is done. */
539         wait_event(ccw_device_init_wq,
540                    atomic_read(&ccw_device_init_count) == 0);
541         if (need_reprobe)
542                 css_schedule_reprobe();
543 }
544
545 static DECLARE_WORK(reprobe_idle_work, reprobe_after_idle);
546
547 /* Work function used to reprobe all unregistered subchannels. */
548 static void reprobe_all(struct work_struct *unused)
549 {
550         int ret;
551
552         CIO_MSG_EVENT(4, "reprobe start\n");
553
554         /* Make sure initial subchannel scan is done. */
555         if (atomic_read(&ccw_device_init_count) != 0) {
556                 queue_work(ccw_device_work, &reprobe_idle_work);
557                 return;
558         }
559         need_reprobe = 0;
560         ret = for_each_subchannel_staged(NULL, reprobe_subchannel, NULL);
561
562         CIO_MSG_EVENT(4, "reprobe done (rc=%d, need_reprobe=%d)\n", ret,
563                       need_reprobe);
564 }
565
566 static DECLARE_WORK(css_reprobe_work, reprobe_all);
567
568 /* Schedule reprobing of all unregistered subchannels. */
569 void css_schedule_reprobe(void)
570 {
571         need_reprobe = 1;
572         queue_work(slow_path_wq, &css_reprobe_work);
573 }
574
575 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
576
577 /*
578  * Called from the machine check handler for subchannel report words.
579  */
580 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
581 {
582         struct subchannel_id mchk_schid;
583
584         if (overflow) {
585                 css_schedule_eval_all();
586                 return;
587         }
588         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
589                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
590                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
591                       crw0->erc, crw0->rsid);
592         if (crw1)
593                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
594                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
595                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
596                               crw1->anc, crw1->erc, crw1->rsid);
597         init_subchannel_id(&mchk_schid);
598         mchk_schid.sch_no = crw0->rsid;
599         if (crw1)
600                 mchk_schid.ssid = (crw1->rsid >> 8) & 3;
601
602         /*
603          * Since we are always presented with IPI in the CRW, we have to
604          * use stsch() to find out if the subchannel in question has come
605          * or gone.
606          */
607         css_evaluate_subchannel(mchk_schid, 0);
608 }
609
610 static int __init
611 __init_channel_subsystem(struct subchannel_id schid, void *data)
612 {
613         struct subchannel *sch;
614         int ret;
615
616         if (cio_is_console(schid))
617                 sch = cio_get_console_subchannel();
618         else {
619                 sch = css_alloc_subchannel(schid);
620                 if (IS_ERR(sch))
621                         ret = PTR_ERR(sch);
622                 else
623                         ret = 0;
624                 switch (ret) {
625                 case 0:
626                         break;
627                 case -ENOMEM:
628                         panic("Out of memory in init_channel_subsystem\n");
629                 /* -ENXIO: no more subchannels. */
630                 case -ENXIO:
631                         return ret;
632                 /* -EIO: this subchannel set not supported. */
633                 case -EIO:
634                         return ret;
635                 default:
636                         return 0;
637                 }
638         }
639         /*
640          * We register ALL valid subchannels in ioinfo, even those
641          * that have been present before init_channel_subsystem.
642          * These subchannels can't have been registered yet (kmalloc
643          * not working) so we do it now. This is true e.g. for the
644          * console subchannel.
645          */
646         css_register_subchannel(sch);
647         return 0;
648 }
649
650 static void __init
651 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
652 {
653         if (css_general_characteristics.mcss) {
654                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
655                 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
656         } else {
657 #ifdef CONFIG_SMP
658                 css->global_pgid.pgid_high.cpu_addr = stap();
659 #else
660                 css->global_pgid.pgid_high.cpu_addr = 0;
661 #endif
662         }
663         css->global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
664         css->global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
665         css->global_pgid.tod_high = tod_high;
666
667 }
668
669 static void
670 channel_subsystem_release(struct device *dev)
671 {
672         struct channel_subsystem *css;
673
674         css = to_css(dev);
675         mutex_destroy(&css->mutex);
676         if (css->pseudo_subchannel) {
677                 /* Implies that it has been generated but never registered. */
678                 css_subchannel_release(&css->pseudo_subchannel->dev);
679                 css->pseudo_subchannel = NULL;
680         }
681         kfree(css);
682 }
683
684 static ssize_t
685 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
686                    char *buf)
687 {
688         struct channel_subsystem *css = to_css(dev);
689         int ret;
690
691         if (!css)
692                 return 0;
693         mutex_lock(&css->mutex);
694         ret = sprintf(buf, "%x\n", css->cm_enabled);
695         mutex_unlock(&css->mutex);
696         return ret;
697 }
698
699 static ssize_t
700 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
701                     const char *buf, size_t count)
702 {
703         struct channel_subsystem *css = to_css(dev);
704         int ret;
705         unsigned long val;
706
707         ret = strict_strtoul(buf, 16, &val);
708         if (ret)
709                 return ret;
710         mutex_lock(&css->mutex);
711         switch (val) {
712         case 0:
713                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
714                 break;
715         case 1:
716                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
717                 break;
718         default:
719                 ret = -EINVAL;
720         }
721         mutex_unlock(&css->mutex);
722         return ret < 0 ? ret : count;
723 }
724
725 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
726
727 static int __init setup_css(int nr)
728 {
729         u32 tod_high;
730         int ret;
731         struct channel_subsystem *css;
732
733         css = channel_subsystems[nr];
734         memset(css, 0, sizeof(struct channel_subsystem));
735         css->pseudo_subchannel =
736                 kzalloc(sizeof(*css->pseudo_subchannel), GFP_KERNEL);
737         if (!css->pseudo_subchannel)
738                 return -ENOMEM;
739         css->pseudo_subchannel->dev.parent = &css->device;
740         css->pseudo_subchannel->dev.release = css_subchannel_release;
741         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
742         ret = cio_create_sch_lock(css->pseudo_subchannel);
743         if (ret) {
744                 kfree(css->pseudo_subchannel);
745                 return ret;
746         }
747         mutex_init(&css->mutex);
748         css->valid = 1;
749         css->cssid = nr;
750         dev_set_name(&css->device, "css%x", nr);
751         css->device.release = channel_subsystem_release;
752         tod_high = (u32) (get_clock() >> 32);
753         css_generate_pgid(css, tod_high);
754         return 0;
755 }
756
757 static int css_reboot_event(struct notifier_block *this,
758                             unsigned long event,
759                             void *ptr)
760 {
761         int ret, i;
762
763         ret = NOTIFY_DONE;
764         for (i = 0; i <= __MAX_CSSID; i++) {
765                 struct channel_subsystem *css;
766
767                 css = channel_subsystems[i];
768                 mutex_lock(&css->mutex);
769                 if (css->cm_enabled)
770                         if (chsc_secm(css, 0))
771                                 ret = NOTIFY_BAD;
772                 mutex_unlock(&css->mutex);
773         }
774
775         return ret;
776 }
777
778 static struct notifier_block css_reboot_notifier = {
779         .notifier_call = css_reboot_event,
780 };
781
782 /*
783  * Now that the driver core is running, we can setup our channel subsystem.
784  * The struct subchannel's are created during probing (except for the
785  * static console subchannel).
786  */
787 static int __init
788 init_channel_subsystem (void)
789 {
790         int ret, i;
791
792         ret = chsc_determine_css_characteristics();
793         if (ret == -ENOMEM)
794                 goto out; /* No need to continue. */
795
796         ret = chsc_alloc_sei_area();
797         if (ret)
798                 goto out;
799
800         ret = slow_subchannel_init();
801         if (ret)
802                 goto out;
803
804         ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
805         if (ret)
806                 goto out;
807
808         if ((ret = bus_register(&css_bus_type)))
809                 goto out;
810
811         /* Try to enable MSS. */
812         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
813         switch (ret) {
814         case 0: /* Success. */
815                 max_ssid = __MAX_SSID;
816                 break;
817         case -ENOMEM:
818                 goto out_bus;
819         default:
820                 max_ssid = 0;
821         }
822         /* Setup css structure. */
823         for (i = 0; i <= __MAX_CSSID; i++) {
824                 struct channel_subsystem *css;
825
826                 css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
827                 if (!css) {
828                         ret = -ENOMEM;
829                         goto out_unregister;
830                 }
831                 channel_subsystems[i] = css;
832                 ret = setup_css(i);
833                 if (ret) {
834                         kfree(channel_subsystems[i]);
835                         goto out_unregister;
836                 }
837                 ret = device_register(&css->device);
838                 if (ret) {
839                         put_device(&css->device);
840                         goto out_unregister;
841                 }
842                 if (css_chsc_characteristics.secm) {
843                         ret = device_create_file(&css->device,
844                                                  &dev_attr_cm_enable);
845                         if (ret)
846                                 goto out_device;
847                 }
848                 ret = device_register(&css->pseudo_subchannel->dev);
849                 if (ret)
850                         goto out_file;
851         }
852         ret = register_reboot_notifier(&css_reboot_notifier);
853         if (ret)
854                 goto out_unregister;
855         css_init_done = 1;
856
857         /* Enable default isc for I/O subchannels. */
858         isc_register(IO_SCH_ISC);
859
860         for_each_subchannel(__init_channel_subsystem, NULL);
861         return 0;
862 out_file:
863         if (css_chsc_characteristics.secm)
864                 device_remove_file(&channel_subsystems[i]->device,
865                                    &dev_attr_cm_enable);
866 out_device:
867         device_unregister(&channel_subsystems[i]->device);
868 out_unregister:
869         while (i > 0) {
870                 struct channel_subsystem *css;
871
872                 i--;
873                 css = channel_subsystems[i];
874                 device_unregister(&css->pseudo_subchannel->dev);
875                 css->pseudo_subchannel = NULL;
876                 if (css_chsc_characteristics.secm)
877                         device_remove_file(&css->device,
878                                            &dev_attr_cm_enable);
879                 device_unregister(&css->device);
880         }
881 out_bus:
882         bus_unregister(&css_bus_type);
883 out:
884         crw_unregister_handler(CRW_RSC_CSS);
885         chsc_free_sei_area();
886         kfree(slow_subchannel_set);
887         pr_alert("The CSS device driver initialization failed with "
888                  "errno=%d\n", ret);
889         return ret;
890 }
891
892 int sch_is_pseudo_sch(struct subchannel *sch)
893 {
894         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
895 }
896
897 static int css_bus_match(struct device *dev, struct device_driver *drv)
898 {
899         struct subchannel *sch = to_subchannel(dev);
900         struct css_driver *driver = to_cssdriver(drv);
901         struct css_device_id *id;
902
903         for (id = driver->subchannel_type; id->match_flags; id++) {
904                 if (sch->st == id->type)
905                         return 1;
906         }
907
908         return 0;
909 }
910
911 static int css_probe(struct device *dev)
912 {
913         struct subchannel *sch;
914         int ret;
915
916         sch = to_subchannel(dev);
917         sch->driver = to_cssdriver(dev->driver);
918         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
919         if (ret)
920                 sch->driver = NULL;
921         return ret;
922 }
923
924 static int css_remove(struct device *dev)
925 {
926         struct subchannel *sch;
927         int ret;
928
929         sch = to_subchannel(dev);
930         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
931         sch->driver = NULL;
932         return ret;
933 }
934
935 static void css_shutdown(struct device *dev)
936 {
937         struct subchannel *sch;
938
939         sch = to_subchannel(dev);
940         if (sch->driver && sch->driver->shutdown)
941                 sch->driver->shutdown(sch);
942 }
943
944 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
945 {
946         struct subchannel *sch = to_subchannel(dev);
947         int ret;
948
949         ret = add_uevent_var(env, "ST=%01X", sch->st);
950         if (ret)
951                 return ret;
952         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
953         return ret;
954 }
955
956 struct bus_type css_bus_type = {
957         .name     = "css",
958         .match    = css_bus_match,
959         .probe    = css_probe,
960         .remove   = css_remove,
961         .shutdown = css_shutdown,
962         .uevent   = css_uevent,
963 };
964
965 /**
966  * css_driver_register - register a css driver
967  * @cdrv: css driver to register
968  *
969  * This is mainly a wrapper around driver_register that sets name
970  * and bus_type in the embedded struct device_driver correctly.
971  */
972 int css_driver_register(struct css_driver *cdrv)
973 {
974         cdrv->drv.name = cdrv->name;
975         cdrv->drv.bus = &css_bus_type;
976         cdrv->drv.owner = cdrv->owner;
977         return driver_register(&cdrv->drv);
978 }
979 EXPORT_SYMBOL_GPL(css_driver_register);
980
981 /**
982  * css_driver_unregister - unregister a css driver
983  * @cdrv: css driver to unregister
984  *
985  * This is a wrapper around driver_unregister.
986  */
987 void css_driver_unregister(struct css_driver *cdrv)
988 {
989         driver_unregister(&cdrv->drv);
990 }
991 EXPORT_SYMBOL_GPL(css_driver_unregister);
992
993 subsys_initcall(init_channel_subsystem);
994
995 MODULE_LICENSE("GPL");
996 EXPORT_SYMBOL(css_bus_type);