1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * core function to access sclp interface
4  *
5  * Copyright IBM Corp. 1999, 2009
6  *
7  * Author(s): Martin Peschke <mpeschke@de.ibm.com>
8  *	      Martin Schwidefsky <schwidefsky@de.ibm.com>
9  */
10 
11 #include <linux/kernel_stat.h>
12 #include <linux/module.h>
13 #include <linux/err.h>
14 #include <linux/panic_notifier.h>
15 #include <linux/spinlock.h>
16 #include <linux/interrupt.h>
17 #include <linux/timer.h>
18 #include <linux/reboot.h>
19 #include <linux/jiffies.h>
20 #include <linux/init.h>
21 #include <linux/platform_device.h>
22 #include <asm/types.h>
23 #include <asm/irq.h>
24 #include <asm/debug.h>
25 
26 #include "sclp.h"
27 
28 #define SCLP_HEADER		"sclp: "
29 
30 struct sclp_trace_entry {
31 	char id[4] __nonstring;
32 	u32 a;
33 	u64 b;
34 };
35 
36 #define SCLP_TRACE_ENTRY_SIZE		sizeof(struct sclp_trace_entry)
37 #define SCLP_TRACE_MAX_SIZE		128
38 #define SCLP_TRACE_EVENT_MAX_SIZE	64
39 
40 /* Debug trace area intended for all entries in abbreviated form. */
41 DEFINE_STATIC_DEBUG_INFO(sclp_debug, "sclp", 8, 1, SCLP_TRACE_ENTRY_SIZE,
42 			 &debug_hex_ascii_view);
43 
44 /* Error trace area intended for full entries relating to failed requests. */
45 DEFINE_STATIC_DEBUG_INFO(sclp_debug_err, "sclp_err", 4, 1,
46 			 SCLP_TRACE_ENTRY_SIZE, &debug_hex_ascii_view);
47 
48 /* Lock to protect internal data consistency. */
49 static DEFINE_SPINLOCK(sclp_lock);
50 
51 /* Mask of events that we can send to the sclp interface. */
52 static sccb_mask_t sclp_receive_mask;
53 
54 /* Mask of events that we can receive from the sclp interface. */
55 static sccb_mask_t sclp_send_mask;
56 
57 /* List of registered event listeners and senders. */
58 static LIST_HEAD(sclp_reg_list);
59 
60 /* List of queued requests. */
61 static LIST_HEAD(sclp_req_queue);
62 
63 /* Data for read and init requests. */
64 static struct sclp_req sclp_read_req;
65 static struct sclp_req sclp_init_req;
66 static void *sclp_read_sccb;
67 static struct init_sccb *sclp_init_sccb;
68 
69 /* Number of console pages to allocate, used by sclp_con.c and sclp_vt220.c */
70 int sclp_console_pages = SCLP_CONSOLE_PAGES;
71 /* Flag to indicate if buffer pages are dropped on buffer full condition */
72 int sclp_console_drop = 1;
73 /* Number of times the console dropped buffer pages */
74 unsigned long sclp_console_full;
75 
76 /* The currently active SCLP command word. */
77 static sclp_cmdw_t active_cmd;
78 
sclp_trace(int prio,char * id,u32 a,u64 b,bool err)79 static inline void sclp_trace(int prio, char *id, u32 a, u64 b, bool err)
80 {
81 	struct sclp_trace_entry e;
82 
83 	memset(&e, 0, sizeof(e));
84 	strncpy(e.id, id, sizeof(e.id));
85 	e.a = a;
86 	e.b = b;
87 	debug_event(&sclp_debug, prio, &e, sizeof(e));
88 	if (err)
89 		debug_event(&sclp_debug_err, 0, &e, sizeof(e));
90 }
91 
no_zeroes_len(void * data,int len)92 static inline int no_zeroes_len(void *data, int len)
93 {
94 	char *d = data;
95 
96 	/* Minimize trace area usage by not tracing trailing zeroes. */
97 	while (len > SCLP_TRACE_ENTRY_SIZE && d[len - 1] == 0)
98 		len--;
99 
100 	return len;
101 }
102 
sclp_trace_bin(int prio,void * d,int len,int errlen)103 static inline void sclp_trace_bin(int prio, void *d, int len, int errlen)
104 {
105 	debug_event(&sclp_debug, prio, d, no_zeroes_len(d, len));
106 	if (errlen)
107 		debug_event(&sclp_debug_err, 0, d, no_zeroes_len(d, errlen));
108 }
109 
abbrev_len(sclp_cmdw_t cmd,struct sccb_header * sccb)110 static inline int abbrev_len(sclp_cmdw_t cmd, struct sccb_header *sccb)
111 {
112 	struct evbuf_header *evbuf = (struct evbuf_header *)(sccb + 1);
113 	int len = sccb->length, limit = SCLP_TRACE_MAX_SIZE;
114 
115 	/* Full SCCB tracing if debug level is set to max. */
116 	if (sclp_debug.level == DEBUG_MAX_LEVEL)
117 		return len;
118 
119 	/* Minimal tracing for console writes. */
120 	if (cmd == SCLP_CMDW_WRITE_EVENT_DATA &&
121 	    (evbuf->type == EVTYP_MSG  || evbuf->type == EVTYP_VT220MSG))
122 		limit = SCLP_TRACE_ENTRY_SIZE;
123 
124 	return min(len, limit);
125 }
126 
sclp_trace_sccb(int prio,char * id,u32 a,u64 b,sclp_cmdw_t cmd,struct sccb_header * sccb,bool err)127 static inline void sclp_trace_sccb(int prio, char *id, u32 a, u64 b,
128 				   sclp_cmdw_t cmd, struct sccb_header *sccb,
129 				   bool err)
130 {
131 	sclp_trace(prio, id, a, b, err);
132 	if (sccb) {
133 		sclp_trace_bin(prio + 1, sccb, abbrev_len(cmd, sccb),
134 			       err ? sccb->length : 0);
135 	}
136 }
137 
sclp_trace_evbuf(int prio,char * id,u32 a,u64 b,struct evbuf_header * evbuf,bool err)138 static inline void sclp_trace_evbuf(int prio, char *id, u32 a, u64 b,
139 				    struct evbuf_header *evbuf, bool err)
140 {
141 	sclp_trace(prio, id, a, b, err);
142 	sclp_trace_bin(prio + 1, evbuf,
143 		       min((int)evbuf->length, (int)SCLP_TRACE_EVENT_MAX_SIZE),
144 		       err ? evbuf->length : 0);
145 }
146 
sclp_trace_req(int prio,char * id,struct sclp_req * req,bool err)147 static inline void sclp_trace_req(int prio, char *id, struct sclp_req *req,
148 				  bool err)
149 {
150 	struct sccb_header *sccb = req->sccb;
151 	union {
152 		struct {
153 			u16 status;
154 			u16 response;
155 			u16 timeout;
156 			u16 start_count;
157 		};
158 		u64 b;
159 	} summary;
160 
161 	summary.status = req->status;
162 	summary.response = sccb ? sccb->response_code : 0;
163 	summary.timeout = (u16)req->queue_timeout;
164 	summary.start_count = (u16)req->start_count;
165 
166 	sclp_trace(prio, id, __pa(sccb), summary.b, err);
167 }
168 
sclp_trace_register(int prio,char * id,u32 a,u64 b,struct sclp_register * reg)169 static inline void sclp_trace_register(int prio, char *id, u32 a, u64 b,
170 				       struct sclp_register *reg)
171 {
172 	struct {
173 		u64 receive;
174 		u64 send;
175 	} d;
176 
177 	d.receive = reg->receive_mask;
178 	d.send = reg->send_mask;
179 
180 	sclp_trace(prio, id, a, b, false);
181 	sclp_trace_bin(prio, &d, sizeof(d), 0);
182 }
183 
sclp_setup_console_pages(char * str)184 static int __init sclp_setup_console_pages(char *str)
185 {
186 	int pages, rc;
187 
188 	rc = kstrtoint(str, 0, &pages);
189 	if (!rc && pages >= SCLP_CONSOLE_PAGES)
190 		sclp_console_pages = pages;
191 	return 1;
192 }
193 
194 __setup("sclp_con_pages=", sclp_setup_console_pages);
195 
sclp_setup_console_drop(char * str)196 static int __init sclp_setup_console_drop(char *str)
197 {
198 	int drop, rc;
199 
200 	rc = kstrtoint(str, 0, &drop);
201 	if (!rc)
202 		sclp_console_drop = drop;
203 	return 1;
204 }
205 
206 __setup("sclp_con_drop=", sclp_setup_console_drop);
207 
208 /* Timer for request retries. */
209 static struct timer_list sclp_request_timer;
210 
211 /* Timer for queued requests. */
212 static struct timer_list sclp_queue_timer;
213 
214 /* Internal state: is a request active at the sclp? */
215 static volatile enum sclp_running_state_t {
216 	sclp_running_state_idle,
217 	sclp_running_state_running,
218 	sclp_running_state_reset_pending
219 } sclp_running_state = sclp_running_state_idle;
220 
221 /* Internal state: is a read request pending? */
222 static volatile enum sclp_reading_state_t {
223 	sclp_reading_state_idle,
224 	sclp_reading_state_reading
225 } sclp_reading_state = sclp_reading_state_idle;
226 
227 /* Internal state: is the driver currently serving requests? */
228 static volatile enum sclp_activation_state_t {
229 	sclp_activation_state_active,
230 	sclp_activation_state_deactivating,
231 	sclp_activation_state_inactive,
232 	sclp_activation_state_activating
233 } sclp_activation_state = sclp_activation_state_active;
234 
235 /* Internal state: is an init mask request pending? */
236 static volatile enum sclp_mask_state_t {
237 	sclp_mask_state_idle,
238 	sclp_mask_state_initializing
239 } sclp_mask_state = sclp_mask_state_idle;
240 
241 /* Maximum retry counts */
242 #define SCLP_INIT_RETRY		3
243 #define SCLP_MASK_RETRY		3
244 
245 /* Timeout intervals in seconds.*/
246 #define SCLP_BUSY_INTERVAL	10
247 #define SCLP_RETRY_INTERVAL	30
248 
249 static void sclp_request_timeout(bool force_restart);
250 static void sclp_process_queue(void);
251 static void __sclp_make_read_req(void);
252 static int sclp_init_mask(int calculate);
253 static int sclp_init(void);
254 
255 static void
__sclp_queue_read_req(void)256 __sclp_queue_read_req(void)
257 {
258 	if (sclp_reading_state == sclp_reading_state_idle) {
259 		sclp_reading_state = sclp_reading_state_reading;
260 		__sclp_make_read_req();
261 		/* Add request to head of queue */
262 		list_add(&sclp_read_req.list, &sclp_req_queue);
263 	}
264 }
265 
266 /* Set up request retry timer. Called while sclp_lock is locked. */
267 static inline void
__sclp_set_request_timer(unsigned long time,void (* cb)(struct timer_list *))268 __sclp_set_request_timer(unsigned long time, void (*cb)(struct timer_list *))
269 {
270 	del_timer(&sclp_request_timer);
271 	sclp_request_timer.function = cb;
272 	sclp_request_timer.expires = jiffies + time;
273 	add_timer(&sclp_request_timer);
274 }
275 
sclp_request_timeout_restart(struct timer_list * unused)276 static void sclp_request_timeout_restart(struct timer_list *unused)
277 {
278 	sclp_request_timeout(true);
279 }
280 
sclp_request_timeout_normal(struct timer_list * unused)281 static void sclp_request_timeout_normal(struct timer_list *unused)
282 {
283 	sclp_request_timeout(false);
284 }
285 
286 /* Request timeout handler. Restart the request queue. If force_restart,
287  * force restart of running request. */
sclp_request_timeout(bool force_restart)288 static void sclp_request_timeout(bool force_restart)
289 {
290 	unsigned long flags;
291 
292 	/* TMO: A timeout occurred (a=force_restart) */
293 	sclp_trace(2, "TMO", force_restart, 0, true);
294 
295 	spin_lock_irqsave(&sclp_lock, flags);
296 	if (force_restart) {
297 		if (sclp_running_state == sclp_running_state_running) {
298 			/* Break running state and queue NOP read event request
299 			 * to get a defined interface state. */
300 			__sclp_queue_read_req();
301 			sclp_running_state = sclp_running_state_idle;
302 		}
303 	} else {
304 		__sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
305 					 sclp_request_timeout_normal);
306 	}
307 	spin_unlock_irqrestore(&sclp_lock, flags);
308 	sclp_process_queue();
309 }
310 
311 /*
312  * Returns the expire value in jiffies of the next pending request timeout,
313  * if any. Needs to be called with sclp_lock.
314  */
__sclp_req_queue_find_next_timeout(void)315 static unsigned long __sclp_req_queue_find_next_timeout(void)
316 {
317 	unsigned long expires_next = 0;
318 	struct sclp_req *req;
319 
320 	list_for_each_entry(req, &sclp_req_queue, list) {
321 		if (!req->queue_expires)
322 			continue;
323 		if (!expires_next ||
324 		   (time_before(req->queue_expires, expires_next)))
325 				expires_next = req->queue_expires;
326 	}
327 	return expires_next;
328 }
329 
330 /*
331  * Returns expired request, if any, and removes it from the list.
332  */
__sclp_req_queue_remove_expired_req(void)333 static struct sclp_req *__sclp_req_queue_remove_expired_req(void)
334 {
335 	unsigned long flags, now;
336 	struct sclp_req *req;
337 
338 	spin_lock_irqsave(&sclp_lock, flags);
339 	now = jiffies;
340 	/* Don't need list_for_each_safe because we break out after list_del */
341 	list_for_each_entry(req, &sclp_req_queue, list) {
342 		if (!req->queue_expires)
343 			continue;
344 		if (time_before_eq(req->queue_expires, now)) {
345 			if (req->status == SCLP_REQ_QUEUED) {
346 				req->status = SCLP_REQ_QUEUED_TIMEOUT;
347 				list_del(&req->list);
348 				goto out;
349 			}
350 		}
351 	}
352 	req = NULL;
353 out:
354 	spin_unlock_irqrestore(&sclp_lock, flags);
355 	return req;
356 }
357 
358 /*
359  * Timeout handler for queued requests. Removes request from list and
360  * invokes callback. This timer can be set per request in situations where
361  * waiting too long would be harmful to the system, e.g. during SE reboot.
362  */
sclp_req_queue_timeout(struct timer_list * unused)363 static void sclp_req_queue_timeout(struct timer_list *unused)
364 {
365 	unsigned long flags, expires_next;
366 	struct sclp_req *req;
367 
368 	do {
369 		req = __sclp_req_queue_remove_expired_req();
370 
371 		if (req) {
372 			/* RQTM: Request timed out (a=sccb, b=summary) */
373 			sclp_trace_req(2, "RQTM", req, true);
374 		}
375 
376 		if (req && req->callback)
377 			req->callback(req, req->callback_data);
378 	} while (req);
379 
380 	spin_lock_irqsave(&sclp_lock, flags);
381 	expires_next = __sclp_req_queue_find_next_timeout();
382 	if (expires_next)
383 		mod_timer(&sclp_queue_timer, expires_next);
384 	spin_unlock_irqrestore(&sclp_lock, flags);
385 }
386 
sclp_service_call_trace(sclp_cmdw_t command,void * sccb)387 static int sclp_service_call_trace(sclp_cmdw_t command, void *sccb)
388 {
389 	static u64 srvc_count;
390 	int rc;
391 
392 	/* SRV1: Service call about to be issued (a=command, b=sccb address) */
393 	sclp_trace_sccb(0, "SRV1", command, (u64)sccb, command, sccb, false);
394 
395 	rc = sclp_service_call(command, sccb);
396 
397 	/* SRV2: Service call was issued (a=rc, b=SRVC sequence number) */
398 	sclp_trace(0, "SRV2", -rc, ++srvc_count, rc != 0);
399 
400 	if (rc == 0)
401 		active_cmd = command;
402 
403 	return rc;
404 }
405 
406 /* Try to start a request. Return zero if the request was successfully
407  * started or if it will be started at a later time. Return non-zero otherwise.
408  * Called while sclp_lock is locked. */
409 static int
__sclp_start_request(struct sclp_req * req)410 __sclp_start_request(struct sclp_req *req)
411 {
412 	int rc;
413 
414 	if (sclp_running_state != sclp_running_state_idle)
415 		return 0;
416 	del_timer(&sclp_request_timer);
417 	rc = sclp_service_call_trace(req->command, req->sccb);
418 	req->start_count++;
419 
420 	if (rc == 0) {
421 		/* Successfully started request */
422 		req->status = SCLP_REQ_RUNNING;
423 		sclp_running_state = sclp_running_state_running;
424 		__sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
425 					 sclp_request_timeout_restart);
426 		return 0;
427 	} else if (rc == -EBUSY) {
428 		/* Try again later */
429 		__sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
430 					 sclp_request_timeout_normal);
431 		return 0;
432 	}
433 	/* Request failed */
434 	req->status = SCLP_REQ_FAILED;
435 	return rc;
436 }
437 
438 /* Try to start queued requests. */
439 static void
sclp_process_queue(void)440 sclp_process_queue(void)
441 {
442 	struct sclp_req *req;
443 	int rc;
444 	unsigned long flags;
445 
446 	spin_lock_irqsave(&sclp_lock, flags);
447 	if (sclp_running_state != sclp_running_state_idle) {
448 		spin_unlock_irqrestore(&sclp_lock, flags);
449 		return;
450 	}
451 	del_timer(&sclp_request_timer);
452 	while (!list_empty(&sclp_req_queue)) {
453 		req = list_entry(sclp_req_queue.next, struct sclp_req, list);
454 		rc = __sclp_start_request(req);
455 		if (rc == 0)
456 			break;
457 		/* Request failed */
458 		if (req->start_count > 1) {
459 			/* Cannot abort already submitted request - could still
460 			 * be active at the SCLP */
461 			__sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
462 						 sclp_request_timeout_normal);
463 			break;
464 		}
465 		/* Post-processing for aborted request */
466 		list_del(&req->list);
467 
468 		/* RQAB: Request aborted (a=sccb, b=summary) */
469 		sclp_trace_req(2, "RQAB", req, true);
470 
471 		if (req->callback) {
472 			spin_unlock_irqrestore(&sclp_lock, flags);
473 			req->callback(req, req->callback_data);
474 			spin_lock_irqsave(&sclp_lock, flags);
475 		}
476 	}
477 	spin_unlock_irqrestore(&sclp_lock, flags);
478 }
479 
__sclp_can_add_request(struct sclp_req * req)480 static int __sclp_can_add_request(struct sclp_req *req)
481 {
482 	if (req == &sclp_init_req)
483 		return 1;
484 	if (sclp_init_state != sclp_init_state_initialized)
485 		return 0;
486 	if (sclp_activation_state != sclp_activation_state_active)
487 		return 0;
488 	return 1;
489 }
490 
491 /* Queue a new request. Return zero on success, non-zero otherwise. */
492 int
sclp_add_request(struct sclp_req * req)493 sclp_add_request(struct sclp_req *req)
494 {
495 	unsigned long flags;
496 	int rc;
497 
498 	spin_lock_irqsave(&sclp_lock, flags);
499 	if (!__sclp_can_add_request(req)) {
500 		spin_unlock_irqrestore(&sclp_lock, flags);
501 		return -EIO;
502 	}
503 
504 	/* RQAD: Request was added (a=sccb, b=caller) */
505 	sclp_trace(2, "RQAD", __pa(req->sccb), _RET_IP_, false);
506 
507 	req->status = SCLP_REQ_QUEUED;
508 	req->start_count = 0;
509 	list_add_tail(&req->list, &sclp_req_queue);
510 	rc = 0;
511 	if (req->queue_timeout) {
512 		req->queue_expires = jiffies + req->queue_timeout * HZ;
513 		if (!timer_pending(&sclp_queue_timer) ||
514 		    time_after(sclp_queue_timer.expires, req->queue_expires))
515 			mod_timer(&sclp_queue_timer, req->queue_expires);
516 	} else
517 		req->queue_expires = 0;
518 	/* Start if request is first in list */
519 	if (sclp_running_state == sclp_running_state_idle &&
520 	    req->list.prev == &sclp_req_queue) {
521 		rc = __sclp_start_request(req);
522 		if (rc)
523 			list_del(&req->list);
524 	}
525 	spin_unlock_irqrestore(&sclp_lock, flags);
526 	return rc;
527 }
528 
529 EXPORT_SYMBOL(sclp_add_request);
530 
531 /* Dispatch events found in request buffer to registered listeners. Return 0
532  * if all events were dispatched, non-zero otherwise. */
533 static int
sclp_dispatch_evbufs(struct sccb_header * sccb)534 sclp_dispatch_evbufs(struct sccb_header *sccb)
535 {
536 	unsigned long flags;
537 	struct evbuf_header *evbuf;
538 	struct list_head *l;
539 	struct sclp_register *reg;
540 	int offset;
541 	int rc;
542 
543 	spin_lock_irqsave(&sclp_lock, flags);
544 	rc = 0;
545 	for (offset = sizeof(struct sccb_header); offset < sccb->length;
546 	     offset += evbuf->length) {
547 		evbuf = (struct evbuf_header *) ((addr_t) sccb + offset);
548 		/* Check for malformed hardware response */
549 		if (evbuf->length == 0)
550 			break;
551 		/* Search for event handler */
552 		reg = NULL;
553 		list_for_each(l, &sclp_reg_list) {
554 			reg = list_entry(l, struct sclp_register, list);
555 			if (reg->receive_mask & SCLP_EVTYP_MASK(evbuf->type))
556 				break;
557 			else
558 				reg = NULL;
559 		}
560 
561 		/* EVNT: Event callback (b=receiver) */
562 		sclp_trace_evbuf(2, "EVNT", 0, reg ? (u64)reg->receiver_fn : 0,
563 				 evbuf, !reg);
564 
565 		if (reg && reg->receiver_fn) {
566 			spin_unlock_irqrestore(&sclp_lock, flags);
567 			reg->receiver_fn(evbuf);
568 			spin_lock_irqsave(&sclp_lock, flags);
569 		} else if (reg == NULL)
570 			rc = -EOPNOTSUPP;
571 	}
572 	spin_unlock_irqrestore(&sclp_lock, flags);
573 	return rc;
574 }
575 
576 /* Read event data request callback. */
577 static void
sclp_read_cb(struct sclp_req * req,void * data)578 sclp_read_cb(struct sclp_req *req, void *data)
579 {
580 	unsigned long flags;
581 	struct sccb_header *sccb;
582 
583 	sccb = (struct sccb_header *) req->sccb;
584 	if (req->status == SCLP_REQ_DONE && (sccb->response_code == 0x20 ||
585 	    sccb->response_code == 0x220))
586 		sclp_dispatch_evbufs(sccb);
587 	spin_lock_irqsave(&sclp_lock, flags);
588 	sclp_reading_state = sclp_reading_state_idle;
589 	spin_unlock_irqrestore(&sclp_lock, flags);
590 }
591 
592 /* Prepare read event data request. Called while sclp_lock is locked. */
__sclp_make_read_req(void)593 static void __sclp_make_read_req(void)
594 {
595 	struct sccb_header *sccb;
596 
597 	sccb = (struct sccb_header *) sclp_read_sccb;
598 	clear_page(sccb);
599 	memset(&sclp_read_req, 0, sizeof(struct sclp_req));
600 	sclp_read_req.command = SCLP_CMDW_READ_EVENT_DATA;
601 	sclp_read_req.status = SCLP_REQ_QUEUED;
602 	sclp_read_req.start_count = 0;
603 	sclp_read_req.callback = sclp_read_cb;
604 	sclp_read_req.sccb = sccb;
605 	sccb->length = PAGE_SIZE;
606 	sccb->function_code = 0;
607 	sccb->control_mask[2] = 0x80;
608 }
609 
610 /* Search request list for request with matching sccb. Return request if found,
611  * NULL otherwise. Called while sclp_lock is locked. */
612 static inline struct sclp_req *
__sclp_find_req(u32 sccb)613 __sclp_find_req(u32 sccb)
614 {
615 	struct list_head *l;
616 	struct sclp_req *req;
617 
618 	list_for_each(l, &sclp_req_queue) {
619 		req = list_entry(l, struct sclp_req, list);
620 		if (sccb == __pa(req->sccb))
621 			return req;
622 	}
623 	return NULL;
624 }
625 
ok_response(u32 sccb_int,sclp_cmdw_t cmd)626 static bool ok_response(u32 sccb_int, sclp_cmdw_t cmd)
627 {
628 	struct sccb_header *sccb = (struct sccb_header *)__va(sccb_int);
629 	struct evbuf_header *evbuf;
630 	u16 response;
631 
632 	if (!sccb)
633 		return true;
634 
635 	/* Check SCCB response. */
636 	response = sccb->response_code & 0xff;
637 	if (response != 0x10 && response != 0x20)
638 		return false;
639 
640 	/* Check event-processed flag on outgoing events. */
641 	if (cmd == SCLP_CMDW_WRITE_EVENT_DATA) {
642 		evbuf = (struct evbuf_header *)(sccb + 1);
643 		if (!(evbuf->flags & 0x80))
644 			return false;
645 	}
646 
647 	return true;
648 }
649 
650 /* Handler for external interruption. Perform request post-processing.
651  * Prepare read event data request if necessary. Start processing of next
652  * request on queue. */
sclp_interrupt_handler(struct ext_code ext_code,unsigned int param32,unsigned long param64)653 static void sclp_interrupt_handler(struct ext_code ext_code,
654 				   unsigned int param32, unsigned long param64)
655 {
656 	struct sclp_req *req;
657 	u32 finished_sccb;
658 	u32 evbuf_pending;
659 
660 	inc_irq_stat(IRQEXT_SCP);
661 	spin_lock(&sclp_lock);
662 	finished_sccb = param32 & 0xfffffff8;
663 	evbuf_pending = param32 & 0x3;
664 
665 	/* INT: Interrupt received (a=intparm, b=cmd) */
666 	sclp_trace_sccb(0, "INT", param32, active_cmd, active_cmd,
667 			(struct sccb_header *)__va(finished_sccb),
668 			!ok_response(finished_sccb, active_cmd));
669 
670 	if (finished_sccb) {
671 		del_timer(&sclp_request_timer);
672 		sclp_running_state = sclp_running_state_reset_pending;
673 		req = __sclp_find_req(finished_sccb);
674 		if (req) {
675 			/* Request post-processing */
676 			list_del(&req->list);
677 			req->status = SCLP_REQ_DONE;
678 
679 			/* RQOK: Request success (a=sccb, b=summary) */
680 			sclp_trace_req(2, "RQOK", req, false);
681 
682 			if (req->callback) {
683 				spin_unlock(&sclp_lock);
684 				req->callback(req, req->callback_data);
685 				spin_lock(&sclp_lock);
686 			}
687 		} else {
688 			/* UNEX: Unexpected SCCB completion (a=sccb address) */
689 			sclp_trace(0, "UNEX", finished_sccb, 0, true);
690 		}
691 		sclp_running_state = sclp_running_state_idle;
692 		active_cmd = 0;
693 	}
694 	if (evbuf_pending &&
695 	    sclp_activation_state == sclp_activation_state_active)
696 		__sclp_queue_read_req();
697 	spin_unlock(&sclp_lock);
698 	sclp_process_queue();
699 }
700 
701 /* Convert interval in jiffies to TOD ticks. */
702 static inline u64
sclp_tod_from_jiffies(unsigned long jiffies)703 sclp_tod_from_jiffies(unsigned long jiffies)
704 {
705 	return (u64) (jiffies / HZ) << 32;
706 }
707 
708 /* Wait until a currently running request finished. Note: while this function
709  * is running, no timers are served on the calling CPU. */
710 void
sclp_sync_wait(void)711 sclp_sync_wait(void)
712 {
713 	unsigned long long old_tick;
714 	unsigned long flags;
715 	unsigned long cr0, cr0_sync;
716 	static u64 sync_count;
717 	u64 timeout;
718 	int irq_context;
719 
720 	/* SYN1: Synchronous wait start (a=runstate, b=sync count) */
721 	sclp_trace(4, "SYN1", sclp_running_state, ++sync_count, false);
722 
723 	/* We'll be disabling timer interrupts, so we need a custom timeout
724 	 * mechanism */
725 	timeout = 0;
726 	if (timer_pending(&sclp_request_timer)) {
727 		/* Get timeout TOD value */
728 		timeout = get_tod_clock_fast() +
729 			  sclp_tod_from_jiffies(sclp_request_timer.expires -
730 						jiffies);
731 	}
732 	local_irq_save(flags);
733 	/* Prevent bottom half from executing once we force interrupts open */
734 	irq_context = in_interrupt();
735 	if (!irq_context)
736 		local_bh_disable();
737 	/* Enable service-signal interruption, disable timer interrupts */
738 	old_tick = local_tick_disable();
739 	trace_hardirqs_on();
740 	__ctl_store(cr0, 0, 0);
741 	cr0_sync = cr0 & ~CR0_IRQ_SUBCLASS_MASK;
742 	cr0_sync |= 1UL << (63 - 54);
743 	__ctl_load(cr0_sync, 0, 0);
744 	__arch_local_irq_stosm(0x01);
745 	/* Loop until driver state indicates finished request */
746 	while (sclp_running_state != sclp_running_state_idle) {
747 		/* Check for expired request timer */
748 		if (get_tod_clock_fast() > timeout && del_timer(&sclp_request_timer))
749 			sclp_request_timer.function(&sclp_request_timer);
750 		cpu_relax();
751 	}
752 	local_irq_disable();
753 	__ctl_load(cr0, 0, 0);
754 	if (!irq_context)
755 		_local_bh_enable();
756 	local_tick_enable(old_tick);
757 	local_irq_restore(flags);
758 
759 	/* SYN2: Synchronous wait end (a=runstate, b=sync_count) */
760 	sclp_trace(4, "SYN2", sclp_running_state, sync_count, false);
761 }
762 EXPORT_SYMBOL(sclp_sync_wait);
763 
764 /* Dispatch changes in send and receive mask to registered listeners. */
765 static void
sclp_dispatch_state_change(void)766 sclp_dispatch_state_change(void)
767 {
768 	struct list_head *l;
769 	struct sclp_register *reg;
770 	unsigned long flags;
771 	sccb_mask_t receive_mask;
772 	sccb_mask_t send_mask;
773 
774 	do {
775 		spin_lock_irqsave(&sclp_lock, flags);
776 		reg = NULL;
777 		list_for_each(l, &sclp_reg_list) {
778 			reg = list_entry(l, struct sclp_register, list);
779 			receive_mask = reg->send_mask & sclp_receive_mask;
780 			send_mask = reg->receive_mask & sclp_send_mask;
781 			if (reg->sclp_receive_mask != receive_mask ||
782 			    reg->sclp_send_mask != send_mask) {
783 				reg->sclp_receive_mask = receive_mask;
784 				reg->sclp_send_mask = send_mask;
785 				break;
786 			} else
787 				reg = NULL;
788 		}
789 		spin_unlock_irqrestore(&sclp_lock, flags);
790 		if (reg && reg->state_change_fn) {
791 			/* STCG: State-change callback (b=callback) */
792 			sclp_trace(2, "STCG", 0, (u64)reg->state_change_fn,
793 				   false);
794 
795 			reg->state_change_fn(reg);
796 		}
797 	} while (reg);
798 }
799 
800 struct sclp_statechangebuf {
801 	struct evbuf_header	header;
802 	u8		validity_sclp_active_facility_mask : 1;
803 	u8		validity_sclp_receive_mask : 1;
804 	u8		validity_sclp_send_mask : 1;
805 	u8		validity_read_data_function_mask : 1;
806 	u16		_zeros : 12;
807 	u16		mask_length;
808 	u64		sclp_active_facility_mask;
809 	u8		masks[2 * 1021 + 4];	/* variable length */
810 	/*
811 	 * u8		sclp_receive_mask[mask_length];
812 	 * u8		sclp_send_mask[mask_length];
813 	 * u32		read_data_function_mask;
814 	 */
815 } __attribute__((packed));
816 
817 
818 /* State change event callback. Inform listeners of changes. */
819 static void
sclp_state_change_cb(struct evbuf_header * evbuf)820 sclp_state_change_cb(struct evbuf_header *evbuf)
821 {
822 	unsigned long flags;
823 	struct sclp_statechangebuf *scbuf;
824 
825 	BUILD_BUG_ON(sizeof(struct sclp_statechangebuf) > PAGE_SIZE);
826 
827 	scbuf = (struct sclp_statechangebuf *) evbuf;
828 	spin_lock_irqsave(&sclp_lock, flags);
829 	if (scbuf->validity_sclp_receive_mask)
830 		sclp_receive_mask = sccb_get_recv_mask(scbuf);
831 	if (scbuf->validity_sclp_send_mask)
832 		sclp_send_mask = sccb_get_send_mask(scbuf);
833 	spin_unlock_irqrestore(&sclp_lock, flags);
834 	if (scbuf->validity_sclp_active_facility_mask)
835 		sclp.facilities = scbuf->sclp_active_facility_mask;
836 	sclp_dispatch_state_change();
837 }
838 
839 static struct sclp_register sclp_state_change_event = {
840 	.receive_mask = EVTYP_STATECHANGE_MASK,
841 	.receiver_fn = sclp_state_change_cb
842 };
843 
844 /* Calculate receive and send mask of currently registered listeners.
845  * Called while sclp_lock is locked. */
846 static inline void
__sclp_get_mask(sccb_mask_t * receive_mask,sccb_mask_t * send_mask)847 __sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask)
848 {
849 	struct list_head *l;
850 	struct sclp_register *t;
851 
852 	*receive_mask = 0;
853 	*send_mask = 0;
854 	list_for_each(l, &sclp_reg_list) {
855 		t = list_entry(l, struct sclp_register, list);
856 		*receive_mask |= t->receive_mask;
857 		*send_mask |= t->send_mask;
858 	}
859 }
860 
861 /* Register event listener. Return 0 on success, non-zero otherwise. */
862 int
sclp_register(struct sclp_register * reg)863 sclp_register(struct sclp_register *reg)
864 {
865 	unsigned long flags;
866 	sccb_mask_t receive_mask;
867 	sccb_mask_t send_mask;
868 	int rc;
869 
870 	/* REG: Event listener registered (b=caller) */
871 	sclp_trace_register(2, "REG", 0, _RET_IP_, reg);
872 
873 	rc = sclp_init();
874 	if (rc)
875 		return rc;
876 	spin_lock_irqsave(&sclp_lock, flags);
877 	/* Check event mask for collisions */
878 	__sclp_get_mask(&receive_mask, &send_mask);
879 	if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) {
880 		spin_unlock_irqrestore(&sclp_lock, flags);
881 		return -EBUSY;
882 	}
883 	/* Trigger initial state change callback */
884 	reg->sclp_receive_mask = 0;
885 	reg->sclp_send_mask = 0;
886 	list_add(&reg->list, &sclp_reg_list);
887 	spin_unlock_irqrestore(&sclp_lock, flags);
888 	rc = sclp_init_mask(1);
889 	if (rc) {
890 		spin_lock_irqsave(&sclp_lock, flags);
891 		list_del(&reg->list);
892 		spin_unlock_irqrestore(&sclp_lock, flags);
893 	}
894 	return rc;
895 }
896 
897 EXPORT_SYMBOL(sclp_register);
898 
899 /* Unregister event listener. */
900 void
sclp_unregister(struct sclp_register * reg)901 sclp_unregister(struct sclp_register *reg)
902 {
903 	unsigned long flags;
904 
905 	/* UREG: Event listener unregistered (b=caller) */
906 	sclp_trace_register(2, "UREG", 0, _RET_IP_, reg);
907 
908 	spin_lock_irqsave(&sclp_lock, flags);
909 	list_del(&reg->list);
910 	spin_unlock_irqrestore(&sclp_lock, flags);
911 	sclp_init_mask(1);
912 }
913 
914 EXPORT_SYMBOL(sclp_unregister);
915 
916 /* Remove event buffers which are marked processed. Return the number of
917  * remaining event buffers. */
918 int
sclp_remove_processed(struct sccb_header * sccb)919 sclp_remove_processed(struct sccb_header *sccb)
920 {
921 	struct evbuf_header *evbuf;
922 	int unprocessed;
923 	u16 remaining;
924 
925 	evbuf = (struct evbuf_header *) (sccb + 1);
926 	unprocessed = 0;
927 	remaining = sccb->length - sizeof(struct sccb_header);
928 	while (remaining > 0) {
929 		remaining -= evbuf->length;
930 		if (evbuf->flags & 0x80) {
931 			sccb->length -= evbuf->length;
932 			memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length),
933 			       remaining);
934 		} else {
935 			unprocessed++;
936 			evbuf = (struct evbuf_header *)
937 					((addr_t) evbuf + evbuf->length);
938 		}
939 	}
940 	return unprocessed;
941 }
942 
943 EXPORT_SYMBOL(sclp_remove_processed);
944 
945 /* Prepare init mask request. Called while sclp_lock is locked. */
946 static inline void
__sclp_make_init_req(sccb_mask_t receive_mask,sccb_mask_t send_mask)947 __sclp_make_init_req(sccb_mask_t receive_mask, sccb_mask_t send_mask)
948 {
949 	struct init_sccb *sccb = sclp_init_sccb;
950 
951 	clear_page(sccb);
952 	memset(&sclp_init_req, 0, sizeof(struct sclp_req));
953 	sclp_init_req.command = SCLP_CMDW_WRITE_EVENT_MASK;
954 	sclp_init_req.status = SCLP_REQ_FILLED;
955 	sclp_init_req.start_count = 0;
956 	sclp_init_req.callback = NULL;
957 	sclp_init_req.callback_data = NULL;
958 	sclp_init_req.sccb = sccb;
959 	sccb->header.length = sizeof(*sccb);
960 	if (sclp_mask_compat_mode)
961 		sccb->mask_length = SCLP_MASK_SIZE_COMPAT;
962 	else
963 		sccb->mask_length = sizeof(sccb_mask_t);
964 	sccb_set_recv_mask(sccb, receive_mask);
965 	sccb_set_send_mask(sccb, send_mask);
966 	sccb_set_sclp_recv_mask(sccb, 0);
967 	sccb_set_sclp_send_mask(sccb, 0);
968 }
969 
970 /* Start init mask request. If calculate is non-zero, calculate the mask as
971  * requested by registered listeners. Use zero mask otherwise. Return 0 on
972  * success, non-zero otherwise. */
973 static int
sclp_init_mask(int calculate)974 sclp_init_mask(int calculate)
975 {
976 	unsigned long flags;
977 	struct init_sccb *sccb = sclp_init_sccb;
978 	sccb_mask_t receive_mask;
979 	sccb_mask_t send_mask;
980 	int retry;
981 	int rc;
982 	unsigned long wait;
983 
984 	spin_lock_irqsave(&sclp_lock, flags);
985 	/* Check if interface is in appropriate state */
986 	if (sclp_mask_state != sclp_mask_state_idle) {
987 		spin_unlock_irqrestore(&sclp_lock, flags);
988 		return -EBUSY;
989 	}
990 	if (sclp_activation_state == sclp_activation_state_inactive) {
991 		spin_unlock_irqrestore(&sclp_lock, flags);
992 		return -EINVAL;
993 	}
994 	sclp_mask_state = sclp_mask_state_initializing;
995 	/* Determine mask */
996 	if (calculate)
997 		__sclp_get_mask(&receive_mask, &send_mask);
998 	else {
999 		receive_mask = 0;
1000 		send_mask = 0;
1001 	}
1002 	rc = -EIO;
1003 	for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) {
1004 		/* Prepare request */
1005 		__sclp_make_init_req(receive_mask, send_mask);
1006 		spin_unlock_irqrestore(&sclp_lock, flags);
1007 		if (sclp_add_request(&sclp_init_req)) {
1008 			/* Try again later */
1009 			wait = jiffies + SCLP_BUSY_INTERVAL * HZ;
1010 			while (time_before(jiffies, wait))
1011 				sclp_sync_wait();
1012 			spin_lock_irqsave(&sclp_lock, flags);
1013 			continue;
1014 		}
1015 		while (sclp_init_req.status != SCLP_REQ_DONE &&
1016 		       sclp_init_req.status != SCLP_REQ_FAILED)
1017 			sclp_sync_wait();
1018 		spin_lock_irqsave(&sclp_lock, flags);
1019 		if (sclp_init_req.status == SCLP_REQ_DONE &&
1020 		    sccb->header.response_code == 0x20) {
1021 			/* Successful request */
1022 			if (calculate) {
1023 				sclp_receive_mask = sccb_get_sclp_recv_mask(sccb);
1024 				sclp_send_mask = sccb_get_sclp_send_mask(sccb);
1025 			} else {
1026 				sclp_receive_mask = 0;
1027 				sclp_send_mask = 0;
1028 			}
1029 			spin_unlock_irqrestore(&sclp_lock, flags);
1030 			sclp_dispatch_state_change();
1031 			spin_lock_irqsave(&sclp_lock, flags);
1032 			rc = 0;
1033 			break;
1034 		}
1035 	}
1036 	sclp_mask_state = sclp_mask_state_idle;
1037 	spin_unlock_irqrestore(&sclp_lock, flags);
1038 	return rc;
1039 }
1040 
1041 /* Deactivate SCLP interface. On success, new requests will be rejected,
1042  * events will no longer be dispatched. Return 0 on success, non-zero
1043  * otherwise. */
1044 int
sclp_deactivate(void)1045 sclp_deactivate(void)
1046 {
1047 	unsigned long flags;
1048 	int rc;
1049 
1050 	spin_lock_irqsave(&sclp_lock, flags);
1051 	/* Deactivate can only be called when active */
1052 	if (sclp_activation_state != sclp_activation_state_active) {
1053 		spin_unlock_irqrestore(&sclp_lock, flags);
1054 		return -EINVAL;
1055 	}
1056 	sclp_activation_state = sclp_activation_state_deactivating;
1057 	spin_unlock_irqrestore(&sclp_lock, flags);
1058 	rc = sclp_init_mask(0);
1059 	spin_lock_irqsave(&sclp_lock, flags);
1060 	if (rc == 0)
1061 		sclp_activation_state = sclp_activation_state_inactive;
1062 	else
1063 		sclp_activation_state = sclp_activation_state_active;
1064 	spin_unlock_irqrestore(&sclp_lock, flags);
1065 	return rc;
1066 }
1067 
1068 EXPORT_SYMBOL(sclp_deactivate);
1069 
1070 /* Reactivate SCLP interface after sclp_deactivate. On success, new
1071  * requests will be accepted, events will be dispatched again. Return 0 on
1072  * success, non-zero otherwise. */
1073 int
sclp_reactivate(void)1074 sclp_reactivate(void)
1075 {
1076 	unsigned long flags;
1077 	int rc;
1078 
1079 	spin_lock_irqsave(&sclp_lock, flags);
1080 	/* Reactivate can only be called when inactive */
1081 	if (sclp_activation_state != sclp_activation_state_inactive) {
1082 		spin_unlock_irqrestore(&sclp_lock, flags);
1083 		return -EINVAL;
1084 	}
1085 	sclp_activation_state = sclp_activation_state_activating;
1086 	spin_unlock_irqrestore(&sclp_lock, flags);
1087 	rc = sclp_init_mask(1);
1088 	spin_lock_irqsave(&sclp_lock, flags);
1089 	if (rc == 0)
1090 		sclp_activation_state = sclp_activation_state_active;
1091 	else
1092 		sclp_activation_state = sclp_activation_state_inactive;
1093 	spin_unlock_irqrestore(&sclp_lock, flags);
1094 	return rc;
1095 }
1096 
1097 EXPORT_SYMBOL(sclp_reactivate);
1098 
1099 /* Handler for external interruption used during initialization. Modify
1100  * request state to done. */
sclp_check_handler(struct ext_code ext_code,unsigned int param32,unsigned long param64)1101 static void sclp_check_handler(struct ext_code ext_code,
1102 			       unsigned int param32, unsigned long param64)
1103 {
1104 	u32 finished_sccb;
1105 
1106 	inc_irq_stat(IRQEXT_SCP);
1107 	finished_sccb = param32 & 0xfffffff8;
1108 	/* Is this the interrupt we are waiting for? */
1109 	if (finished_sccb == 0)
1110 		return;
1111 	if (finished_sccb != __pa(sclp_init_sccb))
1112 		panic("sclp: unsolicited interrupt for buffer at 0x%x\n",
1113 		      finished_sccb);
1114 	spin_lock(&sclp_lock);
1115 	if (sclp_running_state == sclp_running_state_running) {
1116 		sclp_init_req.status = SCLP_REQ_DONE;
1117 		sclp_running_state = sclp_running_state_idle;
1118 	}
1119 	spin_unlock(&sclp_lock);
1120 }
1121 
1122 /* Initial init mask request timed out. Modify request state to failed. */
1123 static void
sclp_check_timeout(struct timer_list * unused)1124 sclp_check_timeout(struct timer_list *unused)
1125 {
1126 	unsigned long flags;
1127 
1128 	spin_lock_irqsave(&sclp_lock, flags);
1129 	if (sclp_running_state == sclp_running_state_running) {
1130 		sclp_init_req.status = SCLP_REQ_FAILED;
1131 		sclp_running_state = sclp_running_state_idle;
1132 	}
1133 	spin_unlock_irqrestore(&sclp_lock, flags);
1134 }
1135 
1136 /* Perform a check of the SCLP interface. Return zero if the interface is
1137  * available and there are no pending requests from a previous instance.
1138  * Return non-zero otherwise. */
1139 static int
sclp_check_interface(void)1140 sclp_check_interface(void)
1141 {
1142 	struct init_sccb *sccb;
1143 	unsigned long flags;
1144 	int retry;
1145 	int rc;
1146 
1147 	spin_lock_irqsave(&sclp_lock, flags);
1148 	/* Prepare init mask command */
1149 	rc = register_external_irq(EXT_IRQ_SERVICE_SIG, sclp_check_handler);
1150 	if (rc) {
1151 		spin_unlock_irqrestore(&sclp_lock, flags);
1152 		return rc;
1153 	}
1154 	for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) {
1155 		__sclp_make_init_req(0, 0);
1156 		sccb = (struct init_sccb *) sclp_init_req.sccb;
1157 		rc = sclp_service_call_trace(sclp_init_req.command, sccb);
1158 		if (rc == -EIO)
1159 			break;
1160 		sclp_init_req.status = SCLP_REQ_RUNNING;
1161 		sclp_running_state = sclp_running_state_running;
1162 		__sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
1163 					 sclp_check_timeout);
1164 		spin_unlock_irqrestore(&sclp_lock, flags);
1165 		/* Enable service-signal interruption - needs to happen
1166 		 * with IRQs enabled. */
1167 		irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
1168 		/* Wait for signal from interrupt or timeout */
1169 		sclp_sync_wait();
1170 		/* Disable service-signal interruption - needs to happen
1171 		 * with IRQs enabled. */
1172 		irq_subclass_unregister(IRQ_SUBCLASS_SERVICE_SIGNAL);
1173 		spin_lock_irqsave(&sclp_lock, flags);
1174 		del_timer(&sclp_request_timer);
1175 		rc = -EBUSY;
1176 		if (sclp_init_req.status == SCLP_REQ_DONE) {
1177 			if (sccb->header.response_code == 0x20) {
1178 				rc = 0;
1179 				break;
1180 			} else if (sccb->header.response_code == 0x74f0) {
1181 				if (!sclp_mask_compat_mode) {
1182 					sclp_mask_compat_mode = true;
1183 					retry = 0;
1184 				}
1185 			}
1186 		}
1187 	}
1188 	unregister_external_irq(EXT_IRQ_SERVICE_SIG, sclp_check_handler);
1189 	spin_unlock_irqrestore(&sclp_lock, flags);
1190 	return rc;
1191 }
1192 
1193 /* Reboot event handler. Reset send and receive mask to prevent pending SCLP
1194  * events from interfering with rebooted system. */
1195 static int
sclp_reboot_event(struct notifier_block * this,unsigned long event,void * ptr)1196 sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
1197 {
1198 	sclp_deactivate();
1199 	return NOTIFY_DONE;
1200 }
1201 
1202 static struct notifier_block sclp_reboot_notifier = {
1203 	.notifier_call = sclp_reboot_event
1204 };
1205 
con_pages_show(struct device_driver * dev,char * buf)1206 static ssize_t con_pages_show(struct device_driver *dev, char *buf)
1207 {
1208 	return sprintf(buf, "%i\n", sclp_console_pages);
1209 }
1210 
1211 static DRIVER_ATTR_RO(con_pages);
1212 
con_drop_show(struct device_driver * dev,char * buf)1213 static ssize_t con_drop_show(struct device_driver *dev, char *buf)
1214 {
1215 	return sprintf(buf, "%i\n", sclp_console_drop);
1216 }
1217 
1218 static DRIVER_ATTR_RO(con_drop);
1219 
con_full_show(struct device_driver * dev,char * buf)1220 static ssize_t con_full_show(struct device_driver *dev, char *buf)
1221 {
1222 	return sprintf(buf, "%lu\n", sclp_console_full);
1223 }
1224 
1225 static DRIVER_ATTR_RO(con_full);
1226 
1227 static struct attribute *sclp_drv_attrs[] = {
1228 	&driver_attr_con_pages.attr,
1229 	&driver_attr_con_drop.attr,
1230 	&driver_attr_con_full.attr,
1231 	NULL,
1232 };
1233 static struct attribute_group sclp_drv_attr_group = {
1234 	.attrs = sclp_drv_attrs,
1235 };
1236 static const struct attribute_group *sclp_drv_attr_groups[] = {
1237 	&sclp_drv_attr_group,
1238 	NULL,
1239 };
1240 
1241 static struct platform_driver sclp_pdrv = {
1242 	.driver = {
1243 		.name	= "sclp",
1244 		.groups = sclp_drv_attr_groups,
1245 	},
1246 };
1247 
1248 /* Initialize SCLP driver. Return zero if driver is operational, non-zero
1249  * otherwise. */
1250 static int
sclp_init(void)1251 sclp_init(void)
1252 {
1253 	unsigned long flags;
1254 	int rc = 0;
1255 
1256 	spin_lock_irqsave(&sclp_lock, flags);
1257 	/* Check for previous or running initialization */
1258 	if (sclp_init_state != sclp_init_state_uninitialized)
1259 		goto fail_unlock;
1260 	sclp_init_state = sclp_init_state_initializing;
1261 	sclp_read_sccb = (void *) __get_free_page(GFP_ATOMIC | GFP_DMA);
1262 	sclp_init_sccb = (void *) __get_free_page(GFP_ATOMIC | GFP_DMA);
1263 	BUG_ON(!sclp_read_sccb || !sclp_init_sccb);
1264 	/* Set up variables */
1265 	list_add(&sclp_state_change_event.list, &sclp_reg_list);
1266 	timer_setup(&sclp_request_timer, NULL, 0);
1267 	timer_setup(&sclp_queue_timer, sclp_req_queue_timeout, 0);
1268 	/* Check interface */
1269 	spin_unlock_irqrestore(&sclp_lock, flags);
1270 	rc = sclp_check_interface();
1271 	spin_lock_irqsave(&sclp_lock, flags);
1272 	if (rc)
1273 		goto fail_init_state_uninitialized;
1274 	/* Register reboot handler */
1275 	rc = register_reboot_notifier(&sclp_reboot_notifier);
1276 	if (rc)
1277 		goto fail_init_state_uninitialized;
1278 	/* Register interrupt handler */
1279 	rc = register_external_irq(EXT_IRQ_SERVICE_SIG, sclp_interrupt_handler);
1280 	if (rc)
1281 		goto fail_unregister_reboot_notifier;
1282 	sclp_init_state = sclp_init_state_initialized;
1283 	spin_unlock_irqrestore(&sclp_lock, flags);
1284 	/* Enable service-signal external interruption - needs to happen with
1285 	 * IRQs enabled. */
1286 	irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
1287 	sclp_init_mask(1);
1288 	return 0;
1289 
1290 fail_unregister_reboot_notifier:
1291 	unregister_reboot_notifier(&sclp_reboot_notifier);
1292 fail_init_state_uninitialized:
1293 	sclp_init_state = sclp_init_state_uninitialized;
1294 	free_page((unsigned long) sclp_read_sccb);
1295 	free_page((unsigned long) sclp_init_sccb);
1296 fail_unlock:
1297 	spin_unlock_irqrestore(&sclp_lock, flags);
1298 	return rc;
1299 }
1300 
sclp_initcall(void)1301 static __init int sclp_initcall(void)
1302 {
1303 	int rc;
1304 
1305 	rc = platform_driver_register(&sclp_pdrv);
1306 	if (rc)
1307 		return rc;
1308 
1309 	return sclp_init();
1310 }
1311 
1312 arch_initcall(sclp_initcall);
1313