[PATCH] s390: default storage key
[linux-2.6] / drivers / s390 / cio / css.c
1 /*
2  *  drivers/s390/cio/css.c
3  *  driver for channel subsystem
4  *   $Revision: 1.85 $
5  *
6  *    Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
7  *                       IBM Corporation
8  *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
9  *               Cornelia Huck (cohuck@de.ibm.com)
10  */
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/device.h>
14 #include <linux/slab.h>
15 #include <linux/errno.h>
16 #include <linux/list.h>
17
18 #include "css.h"
19 #include "cio.h"
20 #include "cio_debug.h"
21 #include "ioasm.h"
22 #include "chsc.h"
23
24 unsigned int highest_subchannel;
25 int need_rescan = 0;
26 int css_init_done = 0;
27
28 struct pgid global_pgid;
29 int css_characteristics_avail = 0;
30
31 struct device css_bus_device = {
32         .bus_id = "css0",
33 };
34
35 static struct subchannel *
36 css_alloc_subchannel(int irq)
37 {
38         struct subchannel *sch;
39         int ret;
40
41         sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
42         if (sch == NULL)
43                 return ERR_PTR(-ENOMEM);
44         ret = cio_validate_subchannel (sch, irq);
45         if (ret < 0) {
46                 kfree(sch);
47                 return ERR_PTR(ret);
48         }
49         if (irq > highest_subchannel)
50                 highest_subchannel = irq;
51
52         if (sch->st != SUBCHANNEL_TYPE_IO) {
53                 /* For now we ignore all non-io subchannels. */
54                 kfree(sch);
55                 return ERR_PTR(-EINVAL);
56         }
57
58         /* 
59          * Set intparm to subchannel address.
60          * This is fine even on 64bit since the subchannel is always located
61          * under 2G.
62          */
63         sch->schib.pmcw.intparm = (__u32)(unsigned long)sch;
64         ret = cio_modify(sch);
65         if (ret) {
66                 kfree(sch);
67                 return ERR_PTR(ret);
68         }
69         return sch;
70 }
71
72 static void
73 css_free_subchannel(struct subchannel *sch)
74 {
75         if (sch) {
76                 /* Reset intparm to zeroes. */
77                 sch->schib.pmcw.intparm = 0;
78                 cio_modify(sch);
79                 kfree(sch);
80         }
81         
82 }
83
84 static void
85 css_subchannel_release(struct device *dev)
86 {
87         struct subchannel *sch;
88
89         sch = to_subchannel(dev);
90         if (!cio_is_console(sch->irq))
91                 kfree(sch);
92 }
93
94 extern int css_get_ssd_info(struct subchannel *sch);
95
96 static int
97 css_register_subchannel(struct subchannel *sch)
98 {
99         int ret;
100
101         /* Initialize the subchannel structure */
102         sch->dev.parent = &css_bus_device;
103         sch->dev.bus = &css_bus_type;
104         sch->dev.release = &css_subchannel_release;
105         
106         /* make it known to the system */
107         ret = device_register(&sch->dev);
108         if (ret)
109                 printk (KERN_WARNING "%s: could not register %s\n",
110                         __func__, sch->dev.bus_id);
111         else
112                 css_get_ssd_info(sch);
113         return ret;
114 }
115
116 int
117 css_probe_device(int irq)
118 {
119         int ret;
120         struct subchannel *sch;
121
122         sch = css_alloc_subchannel(irq);
123         if (IS_ERR(sch))
124                 return PTR_ERR(sch);
125         ret = css_register_subchannel(sch);
126         if (ret)
127                 css_free_subchannel(sch);
128         return ret;
129 }
130
131 struct subchannel *
132 get_subchannel_by_schid(int irq)
133 {
134         struct subchannel *sch;
135         struct list_head *entry;
136         struct device *dev;
137
138         if (!get_bus(&css_bus_type))
139                 return NULL;
140         down_read(&css_bus_type.subsys.rwsem);
141         sch = NULL;
142         list_for_each(entry, &css_bus_type.devices.list) {
143                 dev = get_device(container_of(entry,
144                                               struct device, bus_list));
145                 if (!dev)
146                         continue;
147                 sch = to_subchannel(dev);
148                 if (sch->irq == irq)
149                         break;
150                 put_device(dev);
151                 sch = NULL;
152         }
153         up_read(&css_bus_type.subsys.rwsem);
154         put_bus(&css_bus_type);
155
156         return sch;
157 }
158
159 static inline int
160 css_get_subchannel_status(struct subchannel *sch, int schid)
161 {
162         struct schib schib;
163         int cc;
164
165         cc = stsch(schid, &schib);
166         if (cc)
167                 return CIO_GONE;
168         if (!schib.pmcw.dnv)
169                 return CIO_GONE;
170         if (sch && sch->schib.pmcw.dnv &&
171             (schib.pmcw.dev != sch->schib.pmcw.dev))
172                 return CIO_REVALIDATE;
173         if (sch && !sch->lpm)
174                 return CIO_NO_PATH;
175         return CIO_OPER;
176 }
177         
178 static int
179 css_evaluate_subchannel(int irq, int slow)
180 {
181         int event, ret, disc;
182         struct subchannel *sch;
183         unsigned long flags;
184
185         sch = get_subchannel_by_schid(irq);
186         disc = sch ? device_is_disconnected(sch) : 0;
187         if (disc && slow) {
188                 if (sch)
189                         put_device(&sch->dev);
190                 return 0; /* Already processed. */
191         }
192         /*
193          * We've got a machine check, so running I/O won't get an interrupt.
194          * Kill any pending timers.
195          */
196         if (sch)
197                 device_kill_pending_timer(sch);
198         if (!disc && !slow) {
199                 if (sch)
200                         put_device(&sch->dev);
201                 return -EAGAIN; /* Will be done on the slow path. */
202         }
203         event = css_get_subchannel_status(sch, irq);
204         CIO_MSG_EVENT(4, "Evaluating schid %04x, event %d, %s, %s path.\n",
205                       irq, event, sch?(disc?"disconnected":"normal"):"unknown",
206                       slow?"slow":"fast");
207         switch (event) {
208         case CIO_NO_PATH:
209         case CIO_GONE:
210                 if (!sch) {
211                         /* Never used this subchannel. Ignore. */
212                         ret = 0;
213                         break;
214                 }
215                 if (disc && (event == CIO_NO_PATH)) {
216                         /*
217                          * Uargh, hack again. Because we don't get a machine
218                          * check on configure on, our path bookkeeping can
219                          * be out of date here (it's fine while we only do
220                          * logical varying or get chsc machine checks). We
221                          * need to force reprobing or we might miss devices
222                          * coming operational again. It won't do harm in real
223                          * no path situations.
224                          */
225                         spin_lock_irqsave(&sch->lock, flags);
226                         device_trigger_reprobe(sch);
227                         spin_unlock_irqrestore(&sch->lock, flags);
228                         ret = 0;
229                         break;
230                 }
231                 if (sch->driver && sch->driver->notify &&
232                     sch->driver->notify(&sch->dev, event)) {
233                         cio_disable_subchannel(sch);
234                         device_set_disconnected(sch);
235                         ret = 0;
236                         break;
237                 }
238                 /*
239                  * Unregister subchannel.
240                  * The device will be killed automatically.
241                  */
242                 cio_disable_subchannel(sch);
243                 device_unregister(&sch->dev);
244                 /* Reset intparm to zeroes. */
245                 sch->schib.pmcw.intparm = 0;
246                 cio_modify(sch);
247                 put_device(&sch->dev);
248                 ret = 0;
249                 break;
250         case CIO_REVALIDATE:
251                 /* 
252                  * Revalidation machine check. Sick.
253                  * We don't notify the driver since we have to throw the device
254                  * away in any case.
255                  */
256                 if (!disc) {
257                         device_unregister(&sch->dev);
258                         /* Reset intparm to zeroes. */
259                         sch->schib.pmcw.intparm = 0;
260                         cio_modify(sch);
261                         put_device(&sch->dev);
262                         ret = css_probe_device(irq);
263                 } else {
264                         /*
265                          * We can't immediately deregister the disconnected
266                          * device since it might block.
267                          */
268                         spin_lock_irqsave(&sch->lock, flags);
269                         device_trigger_reprobe(sch);
270                         spin_unlock_irqrestore(&sch->lock, flags);
271                         ret = 0;
272                 }
273                 break;
274         case CIO_OPER:
275                 if (disc) {
276                         spin_lock_irqsave(&sch->lock, flags);
277                         /* Get device operational again. */
278                         device_trigger_reprobe(sch);
279                         spin_unlock_irqrestore(&sch->lock, flags);
280                 }
281                 ret = sch ? 0 : css_probe_device(irq);
282                 break;
283         default:
284                 BUG();
285                 ret = 0;
286         }
287         return ret;
288 }
289
290 static void
291 css_rescan_devices(void)
292 {
293         int irq, ret;
294
295         for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
296                 ret = css_evaluate_subchannel(irq, 1);
297                 /* No more memory. It doesn't make sense to continue. No
298                  * panic because this can happen in midflight and just
299                  * because we can't use a new device is no reason to crash
300                  * the system. */
301                 if (ret == -ENOMEM)
302                         break;
303                 /* -ENXIO indicates that there are no more subchannels. */
304                 if (ret == -ENXIO)
305                         break;
306         }
307 }
308
309 struct slow_subchannel {
310         struct list_head slow_list;
311         unsigned long schid;
312 };
313
314 static LIST_HEAD(slow_subchannels_head);
315 static DEFINE_SPINLOCK(slow_subchannel_lock);
316
317 static void
318 css_trigger_slow_path(void)
319 {
320         CIO_TRACE_EVENT(4, "slowpath");
321
322         if (need_rescan) {
323                 need_rescan = 0;
324                 css_rescan_devices();
325                 return;
326         }
327
328         spin_lock_irq(&slow_subchannel_lock);
329         while (!list_empty(&slow_subchannels_head)) {
330                 struct slow_subchannel *slow_sch =
331                         list_entry(slow_subchannels_head.next,
332                                    struct slow_subchannel, slow_list);
333
334                 list_del_init(slow_subchannels_head.next);
335                 spin_unlock_irq(&slow_subchannel_lock);
336                 css_evaluate_subchannel(slow_sch->schid, 1);
337                 spin_lock_irq(&slow_subchannel_lock);
338                 kfree(slow_sch);
339         }
340         spin_unlock_irq(&slow_subchannel_lock);
341 }
342
343 typedef void (*workfunc)(void *);
344 DECLARE_WORK(slow_path_work, (workfunc)css_trigger_slow_path, NULL);
345 struct workqueue_struct *slow_path_wq;
346
347 /*
348  * Rescan for new devices. FIXME: This is slow.
349  * This function is called when we have lost CRWs due to overflows and we have
350  * to do subchannel housekeeping.
351  */
352 void
353 css_reiterate_subchannels(void)
354 {
355         css_clear_subchannel_slow_list();
356         need_rescan = 1;
357 }
358
359 /*
360  * Called from the machine check handler for subchannel report words.
361  */
362 int
363 css_process_crw(int irq)
364 {
365         int ret;
366
367         CIO_CRW_EVENT(2, "source is subchannel %04X\n", irq);
368
369         if (need_rescan)
370                 /* We need to iterate all subchannels anyway. */
371                 return -EAGAIN;
372         /* 
373          * Since we are always presented with IPI in the CRW, we have to
374          * use stsch() to find out if the subchannel in question has come
375          * or gone.
376          */
377         ret = css_evaluate_subchannel(irq, 0);
378         if (ret == -EAGAIN) {
379                 if (css_enqueue_subchannel_slow(irq)) {
380                         css_clear_subchannel_slow_list();
381                         need_rescan = 1;
382                 }
383         }
384         return ret;
385 }
386
387 static void __init
388 css_generate_pgid(void)
389 {
390         /* Let's build our path group ID here. */
391         if (css_characteristics_avail && css_general_characteristics.mcss)
392                 global_pgid.cpu_addr = 0x8000;
393         else {
394 #ifdef CONFIG_SMP
395                 global_pgid.cpu_addr = hard_smp_processor_id();
396 #else
397                 global_pgid.cpu_addr = 0;
398 #endif
399         }
400         global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
401         global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
402         global_pgid.tod_high = (__u32) (get_clock() >> 32);
403 }
404
405 /*
406  * Now that the driver core is running, we can setup our channel subsystem.
407  * The struct subchannel's are created during probing (except for the
408  * static console subchannel).
409  */
410 static int __init
411 init_channel_subsystem (void)
412 {
413         int ret, irq;
414
415         if (chsc_determine_css_characteristics() == 0)
416                 css_characteristics_avail = 1;
417
418         css_generate_pgid();
419
420         if ((ret = bus_register(&css_bus_type)))
421                 goto out;
422         if ((ret = device_register (&css_bus_device)))
423                 goto out_bus;
424
425         css_init_done = 1;
426
427         ctl_set_bit(6, 28);
428
429         for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
430                 struct subchannel *sch;
431
432                 if (cio_is_console(irq))
433                         sch = cio_get_console_subchannel();
434                 else {
435                         sch = css_alloc_subchannel(irq);
436                         if (IS_ERR(sch))
437                                 ret = PTR_ERR(sch);
438                         else
439                                 ret = 0;
440                         if (ret == -ENOMEM)
441                                 panic("Out of memory in "
442                                       "init_channel_subsystem\n");
443                         /* -ENXIO: no more subchannels. */
444                         if (ret == -ENXIO)
445                                 break;
446                         if (ret)
447                                 continue;
448                 }
449                 /*
450                  * We register ALL valid subchannels in ioinfo, even those
451                  * that have been present before init_channel_subsystem.
452                  * These subchannels can't have been registered yet (kmalloc
453                  * not working) so we do it now. This is true e.g. for the
454                  * console subchannel.
455                  */
456                 css_register_subchannel(sch);
457         }
458         return 0;
459
460 out_bus:
461         bus_unregister(&css_bus_type);
462 out:
463         return ret;
464 }
465
466 /*
467  * find a driver for a subchannel. They identify by the subchannel
468  * type with the exception that the console subchannel driver has its own
469  * subchannel type although the device is an i/o subchannel
470  */
471 static int
472 css_bus_match (struct device *dev, struct device_driver *drv)
473 {
474         struct subchannel *sch = container_of (dev, struct subchannel, dev);
475         struct css_driver *driver = container_of (drv, struct css_driver, drv);
476
477         if (sch->st == driver->subchannel_type)
478                 return 1;
479
480         return 0;
481 }
482
483 struct bus_type css_bus_type = {
484         .name  = "css",
485         .match = &css_bus_match,
486 };
487
488 subsys_initcall(init_channel_subsystem);
489
490 /*
491  * Register root devices for some drivers. The release function must not be
492  * in the device drivers, so we do it here.
493  */
494 static void
495 s390_root_dev_release(struct device *dev)
496 {
497         kfree(dev);
498 }
499
500 struct device *
501 s390_root_dev_register(const char *name)
502 {
503         struct device *dev;
504         int ret;
505
506         if (!strlen(name))
507                 return ERR_PTR(-EINVAL);
508         dev = kmalloc(sizeof(struct device), GFP_KERNEL);
509         if (!dev)
510                 return ERR_PTR(-ENOMEM);
511         memset(dev, 0, sizeof(struct device));
512         strncpy(dev->bus_id, name, min(strlen(name), (size_t)BUS_ID_SIZE));
513         dev->release = s390_root_dev_release;
514         ret = device_register(dev);
515         if (ret) {
516                 kfree(dev);
517                 return ERR_PTR(ret);
518         }
519         return dev;
520 }
521
522 void
523 s390_root_dev_unregister(struct device *dev)
524 {
525         if (dev)
526                 device_unregister(dev);
527 }
528
529 int
530 css_enqueue_subchannel_slow(unsigned long schid)
531 {
532         struct slow_subchannel *new_slow_sch;
533         unsigned long flags;
534
535         new_slow_sch = kmalloc(sizeof(struct slow_subchannel), GFP_ATOMIC);
536         if (!new_slow_sch)
537                 return -ENOMEM;
538         memset(new_slow_sch, 0, sizeof(struct slow_subchannel));
539         new_slow_sch->schid = schid;
540         spin_lock_irqsave(&slow_subchannel_lock, flags);
541         list_add_tail(&new_slow_sch->slow_list, &slow_subchannels_head);
542         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
543         return 0;
544 }
545
546 void
547 css_clear_subchannel_slow_list(void)
548 {
549         unsigned long flags;
550
551         spin_lock_irqsave(&slow_subchannel_lock, flags);
552         while (!list_empty(&slow_subchannels_head)) {
553                 struct slow_subchannel *slow_sch =
554                         list_entry(slow_subchannels_head.next,
555                                    struct slow_subchannel, slow_list);
556
557                 list_del_init(slow_subchannels_head.next);
558                 kfree(slow_sch);
559         }
560         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
561 }
562
563
564
565 int
566 css_slow_subchannels_exist(void)
567 {
568         return (!list_empty(&slow_subchannels_head));
569 }
570
571 MODULE_LICENSE("GPL");
572 EXPORT_SYMBOL(css_bus_type);
573 EXPORT_SYMBOL(s390_root_dev_register);
574 EXPORT_SYMBOL(s390_root_dev_unregister);
575 EXPORT_SYMBOL_GPL(css_characteristics_avail);