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