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