Merge ../powerpc-merge
[linux-2.6] / drivers / s390 / char / sclp.c
1 /*
2  *  drivers/s390/char/sclp.c
3  *     core function to access sclp interface
4  *
5  *  S390 version
6  *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
7  *    Author(s): Martin Peschke <mpeschke@de.ibm.com>
8  *               Martin Schwidefsky <schwidefsky@de.ibm.com>
9  */
10
11 #include <linux/module.h>
12 #include <linux/err.h>
13 #include <linux/spinlock.h>
14 #include <linux/interrupt.h>
15 #include <linux/timer.h>
16 #include <linux/reboot.h>
17 #include <linux/jiffies.h>
18 #include <asm/types.h>
19 #include <asm/s390_ext.h>
20
21 #include "sclp.h"
22
23 #define SCLP_HEADER             "sclp: "
24
25 /* Structure for register_early_external_interrupt. */
26 static ext_int_info_t ext_int_info_hwc;
27
28 /* Lock to protect internal data consistency. */
29 static DEFINE_SPINLOCK(sclp_lock);
30
31 /* Mask of events that we can receive from the sclp interface. */
32 static sccb_mask_t sclp_receive_mask;
33
34 /* Mask of events that we can send to the sclp interface. */
35 static sccb_mask_t sclp_send_mask;
36
37 /* List of registered event listeners and senders. */
38 static struct list_head sclp_reg_list;
39
40 /* List of queued requests. */
41 static struct list_head sclp_req_queue;
42
43 /* Data for read and and init requests. */
44 static struct sclp_req sclp_read_req;
45 static struct sclp_req sclp_init_req;
46 static char sclp_read_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
47 static char sclp_init_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
48
49 /* Timer for request retries. */
50 static struct timer_list sclp_request_timer;
51
52 /* Internal state: is the driver initialized? */
53 static volatile enum sclp_init_state_t {
54         sclp_init_state_uninitialized,
55         sclp_init_state_initializing,
56         sclp_init_state_initialized
57 } sclp_init_state = sclp_init_state_uninitialized;
58
59 /* Internal state: is a request active at the sclp? */
60 static volatile enum sclp_running_state_t {
61         sclp_running_state_idle,
62         sclp_running_state_running
63 } sclp_running_state = sclp_running_state_idle;
64
65 /* Internal state: is a read request pending? */
66 static volatile enum sclp_reading_state_t {
67         sclp_reading_state_idle,
68         sclp_reading_state_reading
69 } sclp_reading_state = sclp_reading_state_idle;
70
71 /* Internal state: is the driver currently serving requests? */
72 static volatile enum sclp_activation_state_t {
73         sclp_activation_state_active,
74         sclp_activation_state_deactivating,
75         sclp_activation_state_inactive,
76         sclp_activation_state_activating
77 } sclp_activation_state = sclp_activation_state_active;
78
79 /* Internal state: is an init mask request pending? */
80 static volatile enum sclp_mask_state_t {
81         sclp_mask_state_idle,
82         sclp_mask_state_initializing
83 } sclp_mask_state = sclp_mask_state_idle;
84
85 /* Maximum retry counts */
86 #define SCLP_INIT_RETRY         3
87 #define SCLP_MASK_RETRY         3
88
89 /* Timeout intervals in seconds.*/
90 #define SCLP_BUSY_INTERVAL      10
91 #define SCLP_RETRY_INTERVAL     15
92
93 static void sclp_process_queue(void);
94 static int sclp_init_mask(int calculate);
95 static int sclp_init(void);
96
97 /* Perform service call. Return 0 on success, non-zero otherwise. */
98 static int
99 service_call(sclp_cmdw_t command, void *sccb)
100 {
101         int cc;
102
103         __asm__ __volatile__(
104                 "   .insn rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
105                 "   ipm   %0\n"
106                 "   srl   %0,28"
107                 : "=&d" (cc)
108                 : "d" (command), "a" (__pa(sccb))
109                 : "cc", "memory" );
110         if (cc == 3)
111                 return -EIO;
112         if (cc == 2)
113                 return -EBUSY;
114         return 0;
115 }
116
117 /* Request timeout handler. Restart the request queue. If DATA is non-zero,
118  * force restart of running request. */
119 static void
120 sclp_request_timeout(unsigned long data)
121 {
122         unsigned long flags;
123
124         if (data) {
125                 spin_lock_irqsave(&sclp_lock, flags);
126                 sclp_running_state = sclp_running_state_idle;
127                 spin_unlock_irqrestore(&sclp_lock, flags);
128         }
129         sclp_process_queue();
130 }
131
132 /* Set up request retry timer. Called while sclp_lock is locked. */
133 static inline void
134 __sclp_set_request_timer(unsigned long time, void (*function)(unsigned long),
135                          unsigned long data)
136 {
137         del_timer(&sclp_request_timer);
138         sclp_request_timer.function = function;
139         sclp_request_timer.data = data;
140         sclp_request_timer.expires = jiffies + time;
141         add_timer(&sclp_request_timer);
142 }
143
144 /* Try to start a request. Return zero if the request was successfully
145  * started or if it will be started at a later time. Return non-zero otherwise.
146  * Called while sclp_lock is locked. */
147 static int
148 __sclp_start_request(struct sclp_req *req)
149 {
150         int rc;
151
152         if (sclp_running_state != sclp_running_state_idle)
153                 return 0;
154         del_timer(&sclp_request_timer);
155         rc = service_call(req->command, req->sccb);
156         req->start_count++;
157
158         if (rc == 0) {
159                 /* Sucessfully started request */
160                 req->status = SCLP_REQ_RUNNING;
161                 sclp_running_state = sclp_running_state_running;
162                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
163                                          sclp_request_timeout, 1);
164                 return 0;
165         } else if (rc == -EBUSY) {
166                 /* Try again later */
167                 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
168                                          sclp_request_timeout, 0);
169                 return 0;
170         }
171         /* Request failed */
172         req->status = SCLP_REQ_FAILED;
173         return rc;
174 }
175
176 /* Try to start queued requests. */
177 static void
178 sclp_process_queue(void)
179 {
180         struct sclp_req *req;
181         int rc;
182         unsigned long flags;
183
184         spin_lock_irqsave(&sclp_lock, flags);
185         if (sclp_running_state != sclp_running_state_idle) {
186                 spin_unlock_irqrestore(&sclp_lock, flags);
187                 return;
188         }
189         del_timer(&sclp_request_timer);
190         while (!list_empty(&sclp_req_queue)) {
191                 req = list_entry(sclp_req_queue.next, struct sclp_req, list);
192                 rc = __sclp_start_request(req);
193                 if (rc == 0)
194                         break;
195                 /* Request failed. */
196                 list_del(&req->list);
197                 if (req->callback) {
198                         spin_unlock_irqrestore(&sclp_lock, flags);
199                         req->callback(req, req->callback_data);
200                         spin_lock_irqsave(&sclp_lock, flags);
201                 }
202         }
203         spin_unlock_irqrestore(&sclp_lock, flags);
204 }
205
206 /* Queue a new request. Return zero on success, non-zero otherwise. */
207 int
208 sclp_add_request(struct sclp_req *req)
209 {
210         unsigned long flags;
211         int rc;
212
213         spin_lock_irqsave(&sclp_lock, flags);
214         if ((sclp_init_state != sclp_init_state_initialized ||
215              sclp_activation_state != sclp_activation_state_active) &&
216             req != &sclp_init_req) {
217                 spin_unlock_irqrestore(&sclp_lock, flags);
218                 return -EIO;
219         }
220         req->status = SCLP_REQ_QUEUED;
221         req->start_count = 0;
222         list_add_tail(&req->list, &sclp_req_queue);
223         rc = 0;
224         /* Start if request is first in list */
225         if (req->list.prev == &sclp_req_queue) {
226                 rc = __sclp_start_request(req);
227                 if (rc)
228                         list_del(&req->list);
229         }
230         spin_unlock_irqrestore(&sclp_lock, flags);
231         return rc;
232 }
233
234 EXPORT_SYMBOL(sclp_add_request);
235
236 /* Dispatch events found in request buffer to registered listeners. Return 0
237  * if all events were dispatched, non-zero otherwise. */
238 static int
239 sclp_dispatch_evbufs(struct sccb_header *sccb)
240 {
241         unsigned long flags;
242         struct evbuf_header *evbuf;
243         struct list_head *l;
244         struct sclp_register *reg;
245         int offset;
246         int rc;
247
248         spin_lock_irqsave(&sclp_lock, flags);
249         rc = 0;
250         for (offset = sizeof(struct sccb_header); offset < sccb->length;
251              offset += evbuf->length) {
252                 /* Search for event handler */
253                 evbuf = (struct evbuf_header *) ((addr_t) sccb + offset);
254                 reg = NULL;
255                 list_for_each(l, &sclp_reg_list) {
256                         reg = list_entry(l, struct sclp_register, list);
257                         if (reg->receive_mask & (1 << (32 - evbuf->type)))
258                                 break;
259                         else
260                                 reg = NULL;
261                 }
262                 if (reg && reg->receiver_fn) {
263                         spin_unlock_irqrestore(&sclp_lock, flags);
264                         reg->receiver_fn(evbuf);
265                         spin_lock_irqsave(&sclp_lock, flags);
266                 } else if (reg == NULL)
267                         rc = -ENOSYS;
268         }
269         spin_unlock_irqrestore(&sclp_lock, flags);
270         return rc;
271 }
272
273 /* Read event data request callback. */
274 static void
275 sclp_read_cb(struct sclp_req *req, void *data)
276 {
277         unsigned long flags;
278         struct sccb_header *sccb;
279
280         sccb = (struct sccb_header *) req->sccb;
281         if (req->status == SCLP_REQ_DONE && (sccb->response_code == 0x20 ||
282             sccb->response_code == 0x220))
283                 sclp_dispatch_evbufs(sccb);
284         spin_lock_irqsave(&sclp_lock, flags);
285         sclp_reading_state = sclp_reading_state_idle;
286         spin_unlock_irqrestore(&sclp_lock, flags);
287 }
288
289 /* Prepare read event data request. Called while sclp_lock is locked. */
290 static inline void
291 __sclp_make_read_req(void)
292 {
293         struct sccb_header *sccb;
294
295         sccb = (struct sccb_header *) sclp_read_sccb;
296         clear_page(sccb);
297         memset(&sclp_read_req, 0, sizeof(struct sclp_req));
298         sclp_read_req.command = SCLP_CMDW_READDATA;
299         sclp_read_req.status = SCLP_REQ_QUEUED;
300         sclp_read_req.start_count = 0;
301         sclp_read_req.callback = sclp_read_cb;
302         sclp_read_req.sccb = sccb;
303         sccb->length = PAGE_SIZE;
304         sccb->function_code = 0;
305         sccb->control_mask[2] = 0x80;
306 }
307
308 /* Search request list for request with matching sccb. Return request if found,
309  * NULL otherwise. Called while sclp_lock is locked. */
310 static inline struct sclp_req *
311 __sclp_find_req(u32 sccb)
312 {
313         struct list_head *l;
314         struct sclp_req *req;
315
316         list_for_each(l, &sclp_req_queue) {
317                 req = list_entry(l, struct sclp_req, list);
318                 if (sccb == (u32) (addr_t) req->sccb)
319                                 return req;
320         }
321         return NULL;
322 }
323
324 /* Handler for external interruption. Perform request post-processing.
325  * Prepare read event data request if necessary. Start processing of next
326  * request on queue. */
327 static void
328 sclp_interrupt_handler(struct pt_regs *regs, __u16 code)
329 {
330         struct sclp_req *req;
331         u32 finished_sccb;
332         u32 evbuf_pending;
333
334         spin_lock(&sclp_lock);
335         finished_sccb = S390_lowcore.ext_params & 0xfffffff8;
336         evbuf_pending = S390_lowcore.ext_params & 0x3;
337         if (finished_sccb) {
338                 req = __sclp_find_req(finished_sccb);
339                 if (req) {
340                         /* Request post-processing */
341                         list_del(&req->list);
342                         req->status = SCLP_REQ_DONE;
343                         if (req->callback) {
344                                 spin_unlock(&sclp_lock);
345                                 req->callback(req, req->callback_data);
346                                 spin_lock(&sclp_lock);
347                         }
348                 }
349                 sclp_running_state = sclp_running_state_idle;
350         }
351         if (evbuf_pending && sclp_receive_mask != 0 &&
352             sclp_reading_state == sclp_reading_state_idle &&
353             sclp_activation_state == sclp_activation_state_active ) {
354                 sclp_reading_state = sclp_reading_state_reading;
355                 __sclp_make_read_req();
356                 /* Add request to head of queue */
357                 list_add(&sclp_read_req.list, &sclp_req_queue);
358         }
359         spin_unlock(&sclp_lock);
360         sclp_process_queue();
361 }
362
363 /* Return current Time-Of-Day clock. */
364 static inline u64
365 sclp_get_clock(void)
366 {
367         u64 result;
368
369         asm volatile ("STCK 0(%1)" : "=m" (result) : "a" (&(result)) : "cc");
370         return result;
371 }
372
373 /* Convert interval in jiffies to TOD ticks. */
374 static inline u64
375 sclp_tod_from_jiffies(unsigned long jiffies)
376 {
377         return (u64) (jiffies / HZ) << 32;
378 }
379
380 /* Wait until a currently running request finished. Note: while this function
381  * is running, no timers are served on the calling CPU. */
382 void
383 sclp_sync_wait(void)
384 {
385         unsigned long psw_mask;
386         unsigned long cr0, cr0_sync;
387         u64 timeout;
388
389         /* We'll be disabling timer interrupts, so we need a custom timeout
390          * mechanism */
391         timeout = 0;
392         if (timer_pending(&sclp_request_timer)) {
393                 /* Get timeout TOD value */
394                 timeout = sclp_get_clock() +
395                           sclp_tod_from_jiffies(sclp_request_timer.expires -
396                                                 jiffies);
397         }
398         /* Prevent bottom half from executing once we force interrupts open */
399         local_bh_disable();
400         /* Enable service-signal interruption, disable timer interrupts */
401         __ctl_store(cr0, 0, 0);
402         cr0_sync = cr0;
403         cr0_sync |= 0x00000200;
404         cr0_sync &= 0xFFFFF3AC;
405         __ctl_load(cr0_sync, 0, 0);
406         asm volatile ("STOSM 0(%1),0x01"
407                       : "=m" (psw_mask) : "a" (&psw_mask) : "memory");
408         /* Loop until driver state indicates finished request */
409         while (sclp_running_state != sclp_running_state_idle) {
410                 /* Check for expired request timer */
411                 if (timer_pending(&sclp_request_timer) &&
412                     sclp_get_clock() > timeout &&
413                     del_timer(&sclp_request_timer))
414                         sclp_request_timer.function(sclp_request_timer.data);
415                 barrier();
416                 cpu_relax();
417         }
418         /* Restore interrupt settings */
419         asm volatile ("SSM 0(%0)"
420                       : : "a" (&psw_mask) : "memory");
421         __ctl_load(cr0, 0, 0);
422         __local_bh_enable();
423 }
424
425 EXPORT_SYMBOL(sclp_sync_wait);
426
427 /* Dispatch changes in send and receive mask to registered listeners. */
428 static inline void
429 sclp_dispatch_state_change(void)
430 {
431         struct list_head *l;
432         struct sclp_register *reg;
433         unsigned long flags;
434         sccb_mask_t receive_mask;
435         sccb_mask_t send_mask;
436
437         do {
438                 spin_lock_irqsave(&sclp_lock, flags);
439                 reg = NULL;
440                 list_for_each(l, &sclp_reg_list) {
441                         reg = list_entry(l, struct sclp_register, list);
442                         receive_mask = reg->receive_mask & sclp_receive_mask;
443                         send_mask = reg->send_mask & sclp_send_mask;
444                         if (reg->sclp_receive_mask != receive_mask ||
445                             reg->sclp_send_mask != send_mask) {
446                                 reg->sclp_receive_mask = receive_mask;
447                                 reg->sclp_send_mask = send_mask;
448                                 break;
449                         } else
450                                 reg = NULL;
451                 }
452                 spin_unlock_irqrestore(&sclp_lock, flags);
453                 if (reg && reg->state_change_fn)
454                         reg->state_change_fn(reg);
455         } while (reg);
456 }
457
458 struct sclp_statechangebuf {
459         struct evbuf_header     header;
460         u8              validity_sclp_active_facility_mask : 1;
461         u8              validity_sclp_receive_mask : 1;
462         u8              validity_sclp_send_mask : 1;
463         u8              validity_read_data_function_mask : 1;
464         u16             _zeros : 12;
465         u16             mask_length;
466         u64             sclp_active_facility_mask;
467         sccb_mask_t     sclp_receive_mask;
468         sccb_mask_t     sclp_send_mask;
469         u32             read_data_function_mask;
470 } __attribute__((packed));
471
472
473 /* State change event callback. Inform listeners of changes. */
474 static void
475 sclp_state_change_cb(struct evbuf_header *evbuf)
476 {
477         unsigned long flags;
478         struct sclp_statechangebuf *scbuf;
479
480         scbuf = (struct sclp_statechangebuf *) evbuf;
481         if (scbuf->mask_length != sizeof(sccb_mask_t))
482                 return;
483         spin_lock_irqsave(&sclp_lock, flags);
484         if (scbuf->validity_sclp_receive_mask)
485                 sclp_receive_mask = scbuf->sclp_receive_mask;
486         if (scbuf->validity_sclp_send_mask)
487                 sclp_send_mask = scbuf->sclp_send_mask;
488         spin_unlock_irqrestore(&sclp_lock, flags);
489         sclp_dispatch_state_change();
490 }
491
492 static struct sclp_register sclp_state_change_event = {
493         .receive_mask = EvTyp_StateChange_Mask,
494         .receiver_fn = sclp_state_change_cb
495 };
496
497 /* Calculate receive and send mask of currently registered listeners.
498  * Called while sclp_lock is locked. */
499 static inline void
500 __sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask)
501 {
502         struct list_head *l;
503         struct sclp_register *t;
504
505         *receive_mask = 0;
506         *send_mask = 0;
507         list_for_each(l, &sclp_reg_list) {
508                 t = list_entry(l, struct sclp_register, list);
509                 *receive_mask |= t->receive_mask;
510                 *send_mask |= t->send_mask;
511         }
512 }
513
514 /* Register event listener. Return 0 on success, non-zero otherwise. */
515 int
516 sclp_register(struct sclp_register *reg)
517 {
518         unsigned long flags;
519         sccb_mask_t receive_mask;
520         sccb_mask_t send_mask;
521         int rc;
522
523         rc = sclp_init();
524         if (rc)
525                 return rc;
526         spin_lock_irqsave(&sclp_lock, flags);
527         /* Check event mask for collisions */
528         __sclp_get_mask(&receive_mask, &send_mask);
529         if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) {
530                 spin_unlock_irqrestore(&sclp_lock, flags);
531                 return -EBUSY;
532         }
533         /* Trigger initial state change callback */
534         reg->sclp_receive_mask = 0;
535         reg->sclp_send_mask = 0;
536         list_add(&reg->list, &sclp_reg_list);
537         spin_unlock_irqrestore(&sclp_lock, flags);
538         rc = sclp_init_mask(1);
539         if (rc) {
540                 spin_lock_irqsave(&sclp_lock, flags);
541                 list_del(&reg->list);
542                 spin_unlock_irqrestore(&sclp_lock, flags);
543         }
544         return rc;
545 }
546
547 EXPORT_SYMBOL(sclp_register);
548
549 /* Unregister event listener. */
550 void
551 sclp_unregister(struct sclp_register *reg)
552 {
553         unsigned long flags;
554
555         spin_lock_irqsave(&sclp_lock, flags);
556         list_del(&reg->list);
557         spin_unlock_irqrestore(&sclp_lock, flags);
558         sclp_init_mask(1);
559 }
560
561 EXPORT_SYMBOL(sclp_unregister);
562
563 /* Remove event buffers which are marked processed. Return the number of
564  * remaining event buffers. */
565 int
566 sclp_remove_processed(struct sccb_header *sccb)
567 {
568         struct evbuf_header *evbuf;
569         int unprocessed;
570         u16 remaining;
571
572         evbuf = (struct evbuf_header *) (sccb + 1);
573         unprocessed = 0;
574         remaining = sccb->length - sizeof(struct sccb_header);
575         while (remaining > 0) {
576                 remaining -= evbuf->length;
577                 if (evbuf->flags & 0x80) {
578                         sccb->length -= evbuf->length;
579                         memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length),
580                                remaining);
581                 } else {
582                         unprocessed++;
583                         evbuf = (struct evbuf_header *)
584                                         ((addr_t) evbuf + evbuf->length);
585                 }
586         }
587         return unprocessed;
588 }
589
590 EXPORT_SYMBOL(sclp_remove_processed);
591
592 struct init_sccb {
593         struct sccb_header header;
594         u16 _reserved;
595         u16 mask_length;
596         sccb_mask_t receive_mask;
597         sccb_mask_t send_mask;
598         sccb_mask_t sclp_send_mask;
599         sccb_mask_t sclp_receive_mask;
600 } __attribute__((packed));
601
602 /* Prepare init mask request. Called while sclp_lock is locked. */
603 static inline void
604 __sclp_make_init_req(u32 receive_mask, u32 send_mask)
605 {
606         struct init_sccb *sccb;
607
608         sccb = (struct init_sccb *) sclp_init_sccb;
609         clear_page(sccb);
610         memset(&sclp_init_req, 0, sizeof(struct sclp_req));
611         sclp_init_req.command = SCLP_CMDW_WRITEMASK;
612         sclp_init_req.status = SCLP_REQ_FILLED;
613         sclp_init_req.start_count = 0;
614         sclp_init_req.callback = NULL;
615         sclp_init_req.callback_data = NULL;
616         sclp_init_req.sccb = sccb;
617         sccb->header.length = sizeof(struct init_sccb);
618         sccb->mask_length = sizeof(sccb_mask_t);
619         sccb->receive_mask = receive_mask;
620         sccb->send_mask = send_mask;
621         sccb->sclp_receive_mask = 0;
622         sccb->sclp_send_mask = 0;
623 }
624
625 /* Start init mask request. If calculate is non-zero, calculate the mask as
626  * requested by registered listeners. Use zero mask otherwise. Return 0 on
627  * success, non-zero otherwise. */
628 static int
629 sclp_init_mask(int calculate)
630 {
631         unsigned long flags;
632         struct init_sccb *sccb = (struct init_sccb *) sclp_init_sccb;
633         sccb_mask_t receive_mask;
634         sccb_mask_t send_mask;
635         int retry;
636         int rc;
637         unsigned long wait;
638
639         spin_lock_irqsave(&sclp_lock, flags);
640         /* Check if interface is in appropriate state */
641         if (sclp_mask_state != sclp_mask_state_idle) {
642                 spin_unlock_irqrestore(&sclp_lock, flags);
643                 return -EBUSY;
644         }
645         if (sclp_activation_state == sclp_activation_state_inactive) {
646                 spin_unlock_irqrestore(&sclp_lock, flags);
647                 return -EINVAL;
648         }
649         sclp_mask_state = sclp_mask_state_initializing;
650         /* Determine mask */
651         if (calculate)
652                 __sclp_get_mask(&receive_mask, &send_mask);
653         else {
654                 receive_mask = 0;
655                 send_mask = 0;
656         }
657         rc = -EIO;
658         for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) {
659                 /* Prepare request */
660                 __sclp_make_init_req(receive_mask, send_mask);
661                 spin_unlock_irqrestore(&sclp_lock, flags);
662                 if (sclp_add_request(&sclp_init_req)) {
663                         /* Try again later */
664                         wait = jiffies + SCLP_BUSY_INTERVAL * HZ;
665                         while (time_before(jiffies, wait))
666                                 sclp_sync_wait();
667                         spin_lock_irqsave(&sclp_lock, flags);
668                         continue;
669                 }
670                 while (sclp_init_req.status != SCLP_REQ_DONE &&
671                        sclp_init_req.status != SCLP_REQ_FAILED)
672                         sclp_sync_wait();
673                 spin_lock_irqsave(&sclp_lock, flags);
674                 if (sclp_init_req.status == SCLP_REQ_DONE &&
675                     sccb->header.response_code == 0x20) {
676                         /* Successful request */
677                         if (calculate) {
678                                 sclp_receive_mask = sccb->sclp_receive_mask;
679                                 sclp_send_mask = sccb->sclp_send_mask;
680                         } else {
681                                 sclp_receive_mask = 0;
682                                 sclp_send_mask = 0;
683                         }
684                         spin_unlock_irqrestore(&sclp_lock, flags);
685                         sclp_dispatch_state_change();
686                         spin_lock_irqsave(&sclp_lock, flags);
687                         rc = 0;
688                         break;
689                 }
690         }
691         sclp_mask_state = sclp_mask_state_idle;
692         spin_unlock_irqrestore(&sclp_lock, flags);
693         return rc;
694 }
695
696 /* Deactivate SCLP interface. On success, new requests will be rejected,
697  * events will no longer be dispatched. Return 0 on success, non-zero
698  * otherwise. */
699 int
700 sclp_deactivate(void)
701 {
702         unsigned long flags;
703         int rc;
704
705         spin_lock_irqsave(&sclp_lock, flags);
706         /* Deactivate can only be called when active */
707         if (sclp_activation_state != sclp_activation_state_active) {
708                 spin_unlock_irqrestore(&sclp_lock, flags);
709                 return -EINVAL;
710         }
711         sclp_activation_state = sclp_activation_state_deactivating;
712         spin_unlock_irqrestore(&sclp_lock, flags);
713         rc = sclp_init_mask(0);
714         spin_lock_irqsave(&sclp_lock, flags);
715         if (rc == 0)
716                 sclp_activation_state = sclp_activation_state_inactive;
717         else
718                 sclp_activation_state = sclp_activation_state_active;
719         spin_unlock_irqrestore(&sclp_lock, flags);
720         return rc;
721 }
722
723 EXPORT_SYMBOL(sclp_deactivate);
724
725 /* Reactivate SCLP interface after sclp_deactivate. On success, new
726  * requests will be accepted, events will be dispatched again. Return 0 on
727  * success, non-zero otherwise. */
728 int
729 sclp_reactivate(void)
730 {
731         unsigned long flags;
732         int rc;
733
734         spin_lock_irqsave(&sclp_lock, flags);
735         /* Reactivate can only be called when inactive */
736         if (sclp_activation_state != sclp_activation_state_inactive) {
737                 spin_unlock_irqrestore(&sclp_lock, flags);
738                 return -EINVAL;
739         }
740         sclp_activation_state = sclp_activation_state_activating;
741         spin_unlock_irqrestore(&sclp_lock, flags);
742         rc = sclp_init_mask(1);
743         spin_lock_irqsave(&sclp_lock, flags);
744         if (rc == 0)
745                 sclp_activation_state = sclp_activation_state_active;
746         else
747                 sclp_activation_state = sclp_activation_state_inactive;
748         spin_unlock_irqrestore(&sclp_lock, flags);
749         return rc;
750 }
751
752 EXPORT_SYMBOL(sclp_reactivate);
753
754 /* Handler for external interruption used during initialization. Modify
755  * request state to done. */
756 static void
757 sclp_check_handler(struct pt_regs *regs, __u16 code)
758 {
759         u32 finished_sccb;
760
761         finished_sccb = S390_lowcore.ext_params & 0xfffffff8;
762         /* Is this the interrupt we are waiting for? */
763         if (finished_sccb == 0)
764                 return;
765         if (finished_sccb != (u32) (addr_t) sclp_init_sccb) {
766                 printk(KERN_WARNING SCLP_HEADER "unsolicited interrupt "
767                        "for buffer at 0x%x\n", finished_sccb);
768                 return;
769         }
770         spin_lock(&sclp_lock);
771         if (sclp_running_state == sclp_running_state_running) {
772                 sclp_init_req.status = SCLP_REQ_DONE;
773                 sclp_running_state = sclp_running_state_idle;
774         }
775         spin_unlock(&sclp_lock);
776 }
777
778 /* Initial init mask request timed out. Modify request state to failed. */
779 static void
780 sclp_check_timeout(unsigned long data)
781 {
782         unsigned long flags;
783
784         spin_lock_irqsave(&sclp_lock, flags);
785         if (sclp_running_state == sclp_running_state_running) {
786                 sclp_init_req.status = SCLP_REQ_FAILED;
787                 sclp_running_state = sclp_running_state_idle;
788         }
789         spin_unlock_irqrestore(&sclp_lock, flags);
790 }
791
792 /* Perform a check of the SCLP interface. Return zero if the interface is
793  * available and there are no pending requests from a previous instance.
794  * Return non-zero otherwise. */
795 static int
796 sclp_check_interface(void)
797 {
798         struct init_sccb *sccb;
799         unsigned long flags;
800         int retry;
801         int rc;
802
803         spin_lock_irqsave(&sclp_lock, flags);
804         /* Prepare init mask command */
805         rc = register_early_external_interrupt(0x2401, sclp_check_handler,
806                                                &ext_int_info_hwc);
807         if (rc) {
808                 spin_unlock_irqrestore(&sclp_lock, flags);
809                 return rc;
810         }
811         for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) {
812                 __sclp_make_init_req(0, 0);
813                 sccb = (struct init_sccb *) sclp_init_req.sccb;
814                 rc = service_call(sclp_init_req.command, sccb);
815                 if (rc == -EIO)
816                         break;
817                 sclp_init_req.status = SCLP_REQ_RUNNING;
818                 sclp_running_state = sclp_running_state_running;
819                 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
820                                          sclp_check_timeout, 0);
821                 spin_unlock_irqrestore(&sclp_lock, flags);
822                 /* Enable service-signal interruption - needs to happen
823                  * with IRQs enabled. */
824                 ctl_set_bit(0, 9);
825                 /* Wait for signal from interrupt or timeout */
826                 sclp_sync_wait();
827                 /* Disable service-signal interruption - needs to happen
828                  * with IRQs enabled. */
829                 ctl_clear_bit(0,9);
830                 spin_lock_irqsave(&sclp_lock, flags);
831                 del_timer(&sclp_request_timer);
832                 if (sclp_init_req.status == SCLP_REQ_DONE &&
833                     sccb->header.response_code == 0x20) {
834                         rc = 0;
835                         break;
836                 } else
837                         rc = -EBUSY;
838         }
839         unregister_early_external_interrupt(0x2401, sclp_check_handler,
840                                             &ext_int_info_hwc);
841         spin_unlock_irqrestore(&sclp_lock, flags);
842         return rc;
843 }
844
845 /* Reboot event handler. Reset send and receive mask to prevent pending SCLP
846  * events from interfering with rebooted system. */
847 static int
848 sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
849 {
850         sclp_deactivate();
851         return NOTIFY_DONE;
852 }
853
854 static struct notifier_block sclp_reboot_notifier = {
855         .notifier_call = sclp_reboot_event
856 };
857
858 /* Initialize SCLP driver. Return zero if driver is operational, non-zero
859  * otherwise. */
860 static int
861 sclp_init(void)
862 {
863         unsigned long flags;
864         int rc;
865
866         if (!MACHINE_HAS_SCLP)
867                 return -ENODEV;
868         spin_lock_irqsave(&sclp_lock, flags);
869         /* Check for previous or running initialization */
870         if (sclp_init_state != sclp_init_state_uninitialized) {
871                 spin_unlock_irqrestore(&sclp_lock, flags);
872                 return 0;
873         }
874         sclp_init_state = sclp_init_state_initializing;
875         /* Set up variables */
876         INIT_LIST_HEAD(&sclp_req_queue);
877         INIT_LIST_HEAD(&sclp_reg_list);
878         list_add(&sclp_state_change_event.list, &sclp_reg_list);
879         init_timer(&sclp_request_timer);
880         /* Check interface */
881         spin_unlock_irqrestore(&sclp_lock, flags);
882         rc = sclp_check_interface();
883         spin_lock_irqsave(&sclp_lock, flags);
884         if (rc) {
885                 sclp_init_state = sclp_init_state_uninitialized;
886                 spin_unlock_irqrestore(&sclp_lock, flags);
887                 return rc;
888         }
889         /* Register reboot handler */
890         rc = register_reboot_notifier(&sclp_reboot_notifier);
891         if (rc) {
892                 sclp_init_state = sclp_init_state_uninitialized;
893                 spin_unlock_irqrestore(&sclp_lock, flags);
894                 return rc;
895         }
896         /* Register interrupt handler */
897         rc = register_early_external_interrupt(0x2401, sclp_interrupt_handler,
898                                                &ext_int_info_hwc);
899         if (rc) {
900                 unregister_reboot_notifier(&sclp_reboot_notifier);
901                 sclp_init_state = sclp_init_state_uninitialized;
902                 spin_unlock_irqrestore(&sclp_lock, flags);
903                 return rc;
904         }
905         sclp_init_state = sclp_init_state_initialized;
906         spin_unlock_irqrestore(&sclp_lock, flags);
907         /* Enable service-signal external interruption - needs to happen with
908          * IRQs enabled. */
909         ctl_set_bit(0, 9);
910         sclp_init_mask(1);
911         return 0;
912 }