Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6
[linux-2.6] / drivers / s390 / cio / css.c
1 /*
2  *  drivers/s390/cio/css.c
3  *  driver for channel subsystem
4  *
5  *    Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
6  *                       IBM Corporation
7  *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
8  *               Cornelia Huck (cornelia.huck@de.ibm.com)
9  */
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/device.h>
13 #include <linux/slab.h>
14 #include <linux/errno.h>
15 #include <linux/list.h>
16 #include <linux/reboot.h>
17
18 #include "css.h"
19 #include "cio.h"
20 #include "cio_debug.h"
21 #include "ioasm.h"
22 #include "chsc.h"
23 #include "device.h"
24 #include "idset.h"
25 #include "chp.h"
26
27 int css_init_done = 0;
28 static int need_reprobe = 0;
29 static int max_ssid = 0;
30
31 struct channel_subsystem *channel_subsystems[__MAX_CSSID + 1];
32
33 int css_characteristics_avail = 0;
34
35 int
36 for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
37 {
38         struct subchannel_id schid;
39         int ret;
40
41         init_subchannel_id(&schid);
42         ret = -ENODEV;
43         do {
44                 do {
45                         ret = fn(schid, data);
46                         if (ret)
47                                 break;
48                 } while (schid.sch_no++ < __MAX_SUBCHANNEL);
49                 schid.sch_no = 0;
50         } while (schid.ssid++ < max_ssid);
51         return ret;
52 }
53
54 static struct subchannel *
55 css_alloc_subchannel(struct subchannel_id schid)
56 {
57         struct subchannel *sch;
58         int ret;
59
60         sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
61         if (sch == NULL)
62                 return ERR_PTR(-ENOMEM);
63         ret = cio_validate_subchannel (sch, schid);
64         if (ret < 0) {
65                 kfree(sch);
66                 return ERR_PTR(ret);
67         }
68
69         if (sch->st != SUBCHANNEL_TYPE_IO) {
70                 /* For now we ignore all non-io subchannels. */
71                 kfree(sch);
72                 return ERR_PTR(-EINVAL);
73         }
74
75         /* 
76          * Set intparm to subchannel address.
77          * This is fine even on 64bit since the subchannel is always located
78          * under 2G.
79          */
80         sch->schib.pmcw.intparm = (__u32)(unsigned long)sch;
81         ret = cio_modify(sch);
82         if (ret) {
83                 kfree(sch->lock);
84                 kfree(sch);
85                 return ERR_PTR(ret);
86         }
87         return sch;
88 }
89
90 static void
91 css_free_subchannel(struct subchannel *sch)
92 {
93         if (sch) {
94                 /* Reset intparm to zeroes. */
95                 sch->schib.pmcw.intparm = 0;
96                 cio_modify(sch);
97                 kfree(sch->lock);
98                 kfree(sch);
99         }
100 }
101
102 static void
103 css_subchannel_release(struct device *dev)
104 {
105         struct subchannel *sch;
106
107         sch = to_subchannel(dev);
108         if (!cio_is_console(sch->schid)) {
109                 kfree(sch->lock);
110                 kfree(sch);
111         }
112 }
113
114 static int css_sch_device_register(struct subchannel *sch)
115 {
116         int ret;
117
118         mutex_lock(&sch->reg_mutex);
119         ret = device_register(&sch->dev);
120         mutex_unlock(&sch->reg_mutex);
121         return ret;
122 }
123
124 void css_sch_device_unregister(struct subchannel *sch)
125 {
126         mutex_lock(&sch->reg_mutex);
127         device_unregister(&sch->dev);
128         mutex_unlock(&sch->reg_mutex);
129 }
130
131 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
132 {
133         int i;
134         int mask;
135
136         memset(ssd, 0, sizeof(struct chsc_ssd_info));
137         ssd->path_mask = pmcw->pim;
138         for (i = 0; i < 8; i++) {
139                 mask = 0x80 >> i;
140                 if (pmcw->pim & mask) {
141                         chp_id_init(&ssd->chpid[i]);
142                         ssd->chpid[i].id = pmcw->chpid[i];
143                 }
144         }
145 }
146
147 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
148 {
149         int i;
150         int mask;
151
152         for (i = 0; i < 8; i++) {
153                 mask = 0x80 >> i;
154                 if (ssd->path_mask & mask)
155                         if (!chp_is_registered(ssd->chpid[i]))
156                                 chp_new(ssd->chpid[i]);
157         }
158 }
159
160 void css_update_ssd_info(struct subchannel *sch)
161 {
162         int ret;
163
164         if (cio_is_console(sch->schid)) {
165                 /* Console is initialized too early for functions requiring
166                  * memory allocation. */
167                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
168         } else {
169                 ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
170                 if (ret)
171                         ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
172                 ssd_register_chpids(&sch->ssd_info);
173         }
174 }
175
176 static int css_register_subchannel(struct subchannel *sch)
177 {
178         int ret;
179
180         /* Initialize the subchannel structure */
181         sch->dev.parent = &channel_subsystems[0]->device;
182         sch->dev.bus = &css_bus_type;
183         sch->dev.release = &css_subchannel_release;
184         sch->dev.groups = subch_attr_groups;
185         /*
186          * We don't want to generate uevents for I/O subchannels that don't
187          * have a working ccw device behind them since they will be
188          * unregistered before they can be used anyway, so we delay the add
189          * uevent until after device recognition was successful.
190          */
191         if (!cio_is_console(sch->schid))
192                 /* Console is special, no need to suppress. */
193                 sch->dev.uevent_suppress = 1;
194         css_update_ssd_info(sch);
195         /* make it known to the system */
196         ret = css_sch_device_register(sch);
197         if (ret) {
198                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
199                               sch->schid.ssid, sch->schid.sch_no, ret);
200                 return ret;
201         }
202         return ret;
203 }
204
205 static int css_probe_device(struct subchannel_id schid)
206 {
207         int ret;
208         struct subchannel *sch;
209
210         sch = css_alloc_subchannel(schid);
211         if (IS_ERR(sch))
212                 return PTR_ERR(sch);
213         ret = css_register_subchannel(sch);
214         if (ret)
215                 css_free_subchannel(sch);
216         return ret;
217 }
218
219 static int
220 check_subchannel(struct device * dev, void * data)
221 {
222         struct subchannel *sch;
223         struct subchannel_id *schid = data;
224
225         sch = to_subchannel(dev);
226         return schid_equal(&sch->schid, schid);
227 }
228
229 struct subchannel *
230 get_subchannel_by_schid(struct subchannel_id schid)
231 {
232         struct device *dev;
233
234         dev = bus_find_device(&css_bus_type, NULL,
235                               &schid, check_subchannel);
236
237         return dev ? to_subchannel(dev) : NULL;
238 }
239
240 static int css_get_subchannel_status(struct subchannel *sch)
241 {
242         struct schib schib;
243
244         if (stsch(sch->schid, &schib) || !schib.pmcw.dnv)
245                 return CIO_GONE;
246         if (sch->schib.pmcw.dnv && (schib.pmcw.dev != sch->schib.pmcw.dev))
247                 return CIO_REVALIDATE;
248         if (!sch->lpm)
249                 return CIO_NO_PATH;
250         return CIO_OPER;
251 }
252
253 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
254 {
255         int event, ret, disc;
256         unsigned long flags;
257         enum { NONE, UNREGISTER, UNREGISTER_PROBE, REPROBE } action;
258
259         spin_lock_irqsave(sch->lock, flags);
260         disc = device_is_disconnected(sch);
261         if (disc && slow) {
262                 /* Disconnected devices are evaluated directly only.*/
263                 spin_unlock_irqrestore(sch->lock, flags);
264                 return 0;
265         }
266         /* No interrupt after machine check - kill pending timers. */
267         device_kill_pending_timer(sch);
268         if (!disc && !slow) {
269                 /* Non-disconnected devices are evaluated on the slow path. */
270                 spin_unlock_irqrestore(sch->lock, flags);
271                 return -EAGAIN;
272         }
273         event = css_get_subchannel_status(sch);
274         CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
275                       sch->schid.ssid, sch->schid.sch_no, event,
276                       disc ? "disconnected" : "normal",
277                       slow ? "slow" : "fast");
278         /* Analyze subchannel status. */
279         action = NONE;
280         switch (event) {
281         case CIO_NO_PATH:
282                 if (disc) {
283                         /* Check if paths have become available. */
284                         action = REPROBE;
285                         break;
286                 }
287                 /* fall through */
288         case CIO_GONE:
289                 /* Prevent unwanted effects when opening lock. */
290                 cio_disable_subchannel(sch);
291                 device_set_disconnected(sch);
292                 /* Ask driver what to do with device. */
293                 action = UNREGISTER;
294                 if (sch->driver && sch->driver->notify) {
295                         spin_unlock_irqrestore(sch->lock, flags);
296                         ret = sch->driver->notify(&sch->dev, event);
297                         spin_lock_irqsave(sch->lock, flags);
298                         if (ret)
299                                 action = NONE;
300                 }
301                 break;
302         case CIO_REVALIDATE:
303                 /* Device will be removed, so no notify necessary. */
304                 if (disc)
305                         /* Reprobe because immediate unregister might block. */
306                         action = REPROBE;
307                 else
308                         action = UNREGISTER_PROBE;
309                 break;
310         case CIO_OPER:
311                 if (disc)
312                         /* Get device operational again. */
313                         action = REPROBE;
314                 break;
315         }
316         /* Perform action. */
317         ret = 0;
318         switch (action) {
319         case UNREGISTER:
320         case UNREGISTER_PROBE:
321                 /* Unregister device (will use subchannel lock). */
322                 spin_unlock_irqrestore(sch->lock, flags);
323                 css_sch_device_unregister(sch);
324                 spin_lock_irqsave(sch->lock, flags);
325
326                 /* Reset intparm to zeroes. */
327                 sch->schib.pmcw.intparm = 0;
328                 cio_modify(sch);
329                 break;
330         case REPROBE:
331                 device_trigger_reprobe(sch);
332                 break;
333         default:
334                 break;
335         }
336         spin_unlock_irqrestore(sch->lock, flags);
337         /* Probe if necessary. */
338         if (action == UNREGISTER_PROBE)
339                 ret = css_probe_device(sch->schid);
340
341         return ret;
342 }
343
344 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
345 {
346         struct schib schib;
347
348         if (!slow) {
349                 /* Will be done on the slow path. */
350                 return -EAGAIN;
351         }
352         if (stsch_err(schid, &schib) || !schib.pmcw.dnv) {
353                 /* Unusable - ignore. */
354                 return 0;
355         }
356         CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, unknown, "
357                          "slow path.\n", schid.ssid, schid.sch_no, CIO_OPER);
358
359         return css_probe_device(schid);
360 }
361
362 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
363 {
364         struct subchannel *sch;
365         int ret;
366
367         sch = get_subchannel_by_schid(schid);
368         if (sch) {
369                 ret = css_evaluate_known_subchannel(sch, slow);
370                 put_device(&sch->dev);
371         } else
372                 ret = css_evaluate_new_subchannel(schid, slow);
373         if (ret == -EAGAIN)
374                 css_schedule_eval(schid);
375 }
376
377 static struct idset *slow_subchannel_set;
378 static spinlock_t slow_subchannel_lock;
379
380 static int __init slow_subchannel_init(void)
381 {
382         spin_lock_init(&slow_subchannel_lock);
383         slow_subchannel_set = idset_sch_new();
384         if (!slow_subchannel_set) {
385                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
386                 return -ENOMEM;
387         }
388         return 0;
389 }
390
391 static void css_slow_path_func(struct work_struct *unused)
392 {
393         struct subchannel_id schid;
394
395         CIO_TRACE_EVENT(4, "slowpath");
396         spin_lock_irq(&slow_subchannel_lock);
397         init_subchannel_id(&schid);
398         while (idset_sch_get_first(slow_subchannel_set, &schid)) {
399                 idset_sch_del(slow_subchannel_set, schid);
400                 spin_unlock_irq(&slow_subchannel_lock);
401                 css_evaluate_subchannel(schid, 1);
402                 spin_lock_irq(&slow_subchannel_lock);
403         }
404         spin_unlock_irq(&slow_subchannel_lock);
405 }
406
407 static DECLARE_WORK(slow_path_work, css_slow_path_func);
408 struct workqueue_struct *slow_path_wq;
409
410 void css_schedule_eval(struct subchannel_id schid)
411 {
412         unsigned long flags;
413
414         spin_lock_irqsave(&slow_subchannel_lock, flags);
415         idset_sch_add(slow_subchannel_set, schid);
416         queue_work(slow_path_wq, &slow_path_work);
417         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
418 }
419
420 void css_schedule_eval_all(void)
421 {
422         unsigned long flags;
423
424         spin_lock_irqsave(&slow_subchannel_lock, flags);
425         idset_fill(slow_subchannel_set);
426         queue_work(slow_path_wq, &slow_path_work);
427         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
428 }
429
430 /* Reprobe subchannel if unregistered. */
431 static int reprobe_subchannel(struct subchannel_id schid, void *data)
432 {
433         struct subchannel *sch;
434         int ret;
435
436         CIO_MSG_EVENT(6, "cio: reprobe 0.%x.%04x\n",
437                       schid.ssid, schid.sch_no);
438         if (need_reprobe)
439                 return -EAGAIN;
440
441         sch = get_subchannel_by_schid(schid);
442         if (sch) {
443                 /* Already known. */
444                 put_device(&sch->dev);
445                 return 0;
446         }
447
448         ret = css_probe_device(schid);
449         switch (ret) {
450         case 0:
451                 break;
452         case -ENXIO:
453         case -ENOMEM:
454                 /* These should abort looping */
455                 break;
456         default:
457                 ret = 0;
458         }
459
460         return ret;
461 }
462
463 /* Work function used to reprobe all unregistered subchannels. */
464 static void reprobe_all(struct work_struct *unused)
465 {
466         int ret;
467
468         CIO_MSG_EVENT(2, "reprobe start\n");
469
470         need_reprobe = 0;
471         /* Make sure initial subchannel scan is done. */
472         wait_event(ccw_device_init_wq,
473                    atomic_read(&ccw_device_init_count) == 0);
474         ret = for_each_subchannel(reprobe_subchannel, NULL);
475
476         CIO_MSG_EVENT(2, "reprobe done (rc=%d, need_reprobe=%d)\n", ret,
477                       need_reprobe);
478 }
479
480 static DECLARE_WORK(css_reprobe_work, reprobe_all);
481
482 /* Schedule reprobing of all unregistered subchannels. */
483 void css_schedule_reprobe(void)
484 {
485         need_reprobe = 1;
486         queue_work(slow_path_wq, &css_reprobe_work);
487 }
488
489 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
490
491 /*
492  * Called from the machine check handler for subchannel report words.
493  */
494 void css_process_crw(int rsid1, int rsid2)
495 {
496         struct subchannel_id mchk_schid;
497
498         CIO_CRW_EVENT(2, "source is subchannel %04X, subsystem id %x\n",
499                       rsid1, rsid2);
500         init_subchannel_id(&mchk_schid);
501         mchk_schid.sch_no = rsid1;
502         if (rsid2 != 0)
503                 mchk_schid.ssid = (rsid2 >> 8) & 3;
504
505         /* 
506          * Since we are always presented with IPI in the CRW, we have to
507          * use stsch() to find out if the subchannel in question has come
508          * or gone.
509          */
510         css_evaluate_subchannel(mchk_schid, 0);
511 }
512
513 static int __init
514 __init_channel_subsystem(struct subchannel_id schid, void *data)
515 {
516         struct subchannel *sch;
517         int ret;
518
519         if (cio_is_console(schid))
520                 sch = cio_get_console_subchannel();
521         else {
522                 sch = css_alloc_subchannel(schid);
523                 if (IS_ERR(sch))
524                         ret = PTR_ERR(sch);
525                 else
526                         ret = 0;
527                 switch (ret) {
528                 case 0:
529                         break;
530                 case -ENOMEM:
531                         panic("Out of memory in init_channel_subsystem\n");
532                 /* -ENXIO: no more subchannels. */
533                 case -ENXIO:
534                         return ret;
535                 /* -EIO: this subchannel set not supported. */
536                 case -EIO:
537                         return ret;
538                 default:
539                         return 0;
540                 }
541         }
542         /*
543          * We register ALL valid subchannels in ioinfo, even those
544          * that have been present before init_channel_subsystem.
545          * These subchannels can't have been registered yet (kmalloc
546          * not working) so we do it now. This is true e.g. for the
547          * console subchannel.
548          */
549         css_register_subchannel(sch);
550         return 0;
551 }
552
553 static void __init
554 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
555 {
556         if (css_characteristics_avail && css_general_characteristics.mcss) {
557                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
558                 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
559         } else {
560 #ifdef CONFIG_SMP
561                 css->global_pgid.pgid_high.cpu_addr = hard_smp_processor_id();
562 #else
563                 css->global_pgid.pgid_high.cpu_addr = 0;
564 #endif
565         }
566         css->global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
567         css->global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
568         css->global_pgid.tod_high = tod_high;
569
570 }
571
572 static void
573 channel_subsystem_release(struct device *dev)
574 {
575         struct channel_subsystem *css;
576
577         css = to_css(dev);
578         mutex_destroy(&css->mutex);
579         kfree(css);
580 }
581
582 static ssize_t
583 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
584                    char *buf)
585 {
586         struct channel_subsystem *css = to_css(dev);
587
588         if (!css)
589                 return 0;
590         return sprintf(buf, "%x\n", css->cm_enabled);
591 }
592
593 static ssize_t
594 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
595                     const char *buf, size_t count)
596 {
597         struct channel_subsystem *css = to_css(dev);
598         int ret;
599
600         switch (buf[0]) {
601         case '0':
602                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
603                 break;
604         case '1':
605                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
606                 break;
607         default:
608                 ret = -EINVAL;
609         }
610         return ret < 0 ? ret : count;
611 }
612
613 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
614
615 static int __init setup_css(int nr)
616 {
617         u32 tod_high;
618         int ret;
619         struct channel_subsystem *css;
620
621         css = channel_subsystems[nr];
622         memset(css, 0, sizeof(struct channel_subsystem));
623         css->pseudo_subchannel =
624                 kzalloc(sizeof(*css->pseudo_subchannel), GFP_KERNEL);
625         if (!css->pseudo_subchannel)
626                 return -ENOMEM;
627         css->pseudo_subchannel->dev.parent = &css->device;
628         css->pseudo_subchannel->dev.release = css_subchannel_release;
629         sprintf(css->pseudo_subchannel->dev.bus_id, "defunct");
630         ret = cio_create_sch_lock(css->pseudo_subchannel);
631         if (ret) {
632                 kfree(css->pseudo_subchannel);
633                 return ret;
634         }
635         mutex_init(&css->mutex);
636         css->valid = 1;
637         css->cssid = nr;
638         sprintf(css->device.bus_id, "css%x", nr);
639         css->device.release = channel_subsystem_release;
640         tod_high = (u32) (get_clock() >> 32);
641         css_generate_pgid(css, tod_high);
642         return 0;
643 }
644
645 static int css_reboot_event(struct notifier_block *this,
646                             unsigned long event,
647                             void *ptr)
648 {
649         int ret, i;
650
651         ret = NOTIFY_DONE;
652         for (i = 0; i <= __MAX_CSSID; i++) {
653                 struct channel_subsystem *css;
654
655                 css = channel_subsystems[i];
656                 if (css->cm_enabled)
657                         if (chsc_secm(css, 0))
658                                 ret = NOTIFY_BAD;
659         }
660
661         return ret;
662 }
663
664 static struct notifier_block css_reboot_notifier = {
665         .notifier_call = css_reboot_event,
666 };
667
668 /*
669  * Now that the driver core is running, we can setup our channel subsystem.
670  * The struct subchannel's are created during probing (except for the
671  * static console subchannel).
672  */
673 static int __init
674 init_channel_subsystem (void)
675 {
676         int ret, i;
677
678         ret = chsc_determine_css_characteristics();
679         if (ret == -ENOMEM)
680                 goto out; /* No need to continue. */
681         if (ret == 0)
682                 css_characteristics_avail = 1;
683
684         ret = chsc_alloc_sei_area();
685         if (ret)
686                 goto out;
687
688         ret = slow_subchannel_init();
689         if (ret)
690                 goto out;
691
692         if ((ret = bus_register(&css_bus_type)))
693                 goto out;
694
695         /* Try to enable MSS. */
696         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
697         switch (ret) {
698         case 0: /* Success. */
699                 max_ssid = __MAX_SSID;
700                 break;
701         case -ENOMEM:
702                 goto out_bus;
703         default:
704                 max_ssid = 0;
705         }
706         /* Setup css structure. */
707         for (i = 0; i <= __MAX_CSSID; i++) {
708                 struct channel_subsystem *css;
709
710                 css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
711                 if (!css) {
712                         ret = -ENOMEM;
713                         goto out_unregister;
714                 }
715                 channel_subsystems[i] = css;
716                 ret = setup_css(i);
717                 if (ret)
718                         goto out_free;
719                 ret = device_register(&css->device);
720                 if (ret)
721                         goto out_free_all;
722                 if (css_characteristics_avail &&
723                     css_chsc_characteristics.secm) {
724                         ret = device_create_file(&css->device,
725                                                  &dev_attr_cm_enable);
726                         if (ret)
727                                 goto out_device;
728                 }
729                 ret = device_register(&css->pseudo_subchannel->dev);
730                 if (ret)
731                         goto out_file;
732         }
733         ret = register_reboot_notifier(&css_reboot_notifier);
734         if (ret)
735                 goto out_pseudo;
736         css_init_done = 1;
737
738         ctl_set_bit(6, 28);
739
740         for_each_subchannel(__init_channel_subsystem, NULL);
741         return 0;
742 out_pseudo:
743         device_unregister(&channel_subsystems[i]->pseudo_subchannel->dev);
744 out_file:
745         device_remove_file(&channel_subsystems[i]->device,
746                            &dev_attr_cm_enable);
747 out_device:
748         device_unregister(&channel_subsystems[i]->device);
749 out_free_all:
750         kfree(channel_subsystems[i]->pseudo_subchannel->lock);
751         kfree(channel_subsystems[i]->pseudo_subchannel);
752 out_free:
753         kfree(channel_subsystems[i]);
754 out_unregister:
755         while (i > 0) {
756                 struct channel_subsystem *css;
757
758                 i--;
759                 css = channel_subsystems[i];
760                 device_unregister(&css->pseudo_subchannel->dev);
761                 if (css_characteristics_avail && css_chsc_characteristics.secm)
762                         device_remove_file(&css->device,
763                                            &dev_attr_cm_enable);
764                 device_unregister(&css->device);
765         }
766 out_bus:
767         bus_unregister(&css_bus_type);
768 out:
769         chsc_free_sei_area();
770         kfree(slow_subchannel_set);
771         printk(KERN_WARNING"cio: failed to initialize css driver (%d)!\n",
772                ret);
773         return ret;
774 }
775
776 int sch_is_pseudo_sch(struct subchannel *sch)
777 {
778         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
779 }
780
781 /*
782  * find a driver for a subchannel. They identify by the subchannel
783  * type with the exception that the console subchannel driver has its own
784  * subchannel type although the device is an i/o subchannel
785  */
786 static int
787 css_bus_match (struct device *dev, struct device_driver *drv)
788 {
789         struct subchannel *sch = container_of (dev, struct subchannel, dev);
790         struct css_driver *driver = container_of (drv, struct css_driver, drv);
791
792         if (sch->st == driver->subchannel_type)
793                 return 1;
794
795         return 0;
796 }
797
798 static int
799 css_probe (struct device *dev)
800 {
801         struct subchannel *sch;
802
803         sch = to_subchannel(dev);
804         sch->driver = container_of (dev->driver, struct css_driver, drv);
805         return (sch->driver->probe ? sch->driver->probe(sch) : 0);
806 }
807
808 static int
809 css_remove (struct device *dev)
810 {
811         struct subchannel *sch;
812
813         sch = to_subchannel(dev);
814         return (sch->driver->remove ? sch->driver->remove(sch) : 0);
815 }
816
817 static void
818 css_shutdown (struct device *dev)
819 {
820         struct subchannel *sch;
821
822         sch = to_subchannel(dev);
823         if (sch->driver->shutdown)
824                 sch->driver->shutdown(sch);
825 }
826
827 struct bus_type css_bus_type = {
828         .name     = "css",
829         .match    = css_bus_match,
830         .probe    = css_probe,
831         .remove   = css_remove,
832         .shutdown = css_shutdown,
833 };
834
835 subsys_initcall(init_channel_subsystem);
836
837 MODULE_LICENSE("GPL");
838 EXPORT_SYMBOL(css_bus_type);
839 EXPORT_SYMBOL_GPL(css_characteristics_avail);