sclp.c

   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/export.h>
  13#include <linux/module.h>
  14#include <linux/err.h>
  15#include <linux/panic_notifier.h>
  16#include <linux/spinlock.h>
  17#include <linux/interrupt.h>
  18#include <linux/timer.h>
  19#include <linux/reboot.h>
  20#include <linux/jiffies.h>
  21#include <linux/init.h>
  22#include <linux/platform_device.h>
  23#include <asm/types.h>
  24#include <asm/irq.h>
  25#include <asm/debug.h>
  26
  27#include "sclp.h"
  28
  29#define SCLP_HEADER		"sclp: "
  30
  31struct sclp_trace_entry {
  32	char id[4] __nonstring;
  33	u32 a;
  34	u64 b;
  35};
  36
  37#define SCLP_TRACE_ENTRY_SIZE		sizeof(struct sclp_trace_entry)
  38#define SCLP_TRACE_MAX_SIZE		128
  39#define SCLP_TRACE_EVENT_MAX_SIZE	64
  40
  41/* Debug trace area intended for all entries in abbreviated form. */
  42DEFINE_STATIC_DEBUG_INFO(sclp_debug, "sclp", 8, 1, SCLP_TRACE_ENTRY_SIZE,
  43			 &debug_hex_ascii_view);
  44
  45/* Error trace area intended for full entries relating to failed requests. */
  46DEFINE_STATIC_DEBUG_INFO(sclp_debug_err, "sclp_err", 4, 1,
  47			 SCLP_TRACE_ENTRY_SIZE, &debug_hex_ascii_view);
  48
  49/* Lock to protect internal data consistency. */
  50static DEFINE_SPINLOCK(sclp_lock);
  51
  52/* Mask of events that we can send to the sclp interface. */
  53static sccb_mask_t sclp_receive_mask;
  54
  55/* Mask of events that we can receive from the sclp interface. */
  56static sccb_mask_t sclp_send_mask;
  57
  58/* List of registered event listeners and senders. */
  59static LIST_HEAD(sclp_reg_list);
  60
  61/* List of queued requests. */
  62static LIST_HEAD(sclp_req_queue);
  63
  64/* Data for read and init requests. */
  65static struct sclp_req sclp_read_req;
  66static struct sclp_req sclp_init_req;
  67static void *sclp_read_sccb;
  68static struct init_sccb *sclp_init_sccb;
  69
  70/* Number of console pages to allocate, used by sclp_con.c and sclp_vt220.c */
  71int sclp_console_pages = SCLP_CONSOLE_PAGES;
  72/* Flag to indicate if buffer pages are dropped on buffer full condition */
  73bool sclp_console_drop = true;
  74/* Number of times the console dropped buffer pages */
  75unsigned long sclp_console_full;
  76
  77/* The currently active SCLP command word. */
  78static sclp_cmdw_t active_cmd;
  79
  80static inline struct sccb_header *sclpint_to_sccb(u32 sccb_int)
  81{
  82	if (sccb_int)
  83		return __va(sccb_int);
  84	return NULL;
  85}
  86
  87static inline void sclp_trace(int prio, char *id, u32 a, u64 b, bool err)
  88{
  89	struct sclp_trace_entry e;
  90
  91	memset(&e, 0, sizeof(e));
  92	strtomem(e.id, id);
  93	e.a = a;
  94	e.b = b;
  95	debug_event(&sclp_debug, prio, &e, sizeof(e));
  96	if (err)
  97		debug_event(&sclp_debug_err, 0, &e, sizeof(e));
  98}
  99
 100static inline int no_zeroes_len(void *data, int len)
 101{
 102	char *d = data;
 103
 104	/* Minimize trace area usage by not tracing trailing zeroes. */
 105	while (len > SCLP_TRACE_ENTRY_SIZE && d[len - 1] == 0)
 106		len--;
 107
 108	return len;
 109}
 110
 111static inline void sclp_trace_bin(int prio, void *d, int len, int errlen)
 112{
 113	debug_event(&sclp_debug, prio, d, no_zeroes_len(d, len));
 114	if (errlen)
 115		debug_event(&sclp_debug_err, 0, d, no_zeroes_len(d, errlen));
 116}
 117
 118static inline int abbrev_len(sclp_cmdw_t cmd, struct sccb_header *sccb)
 119{
 120	struct evbuf_header *evbuf = (struct evbuf_header *)(sccb + 1);
 121	int len = sccb->length, limit = SCLP_TRACE_MAX_SIZE;
 122
 123	/* Full SCCB tracing if debug level is set to max. */
 124	if (sclp_debug.level == DEBUG_MAX_LEVEL)
 125		return len;
 126
 127	/* Minimal tracing for console writes. */
 128	if (cmd == SCLP_CMDW_WRITE_EVENT_DATA &&
 129	    (evbuf->type == EVTYP_MSG  || evbuf->type == EVTYP_VT220MSG))
 130		limit = SCLP_TRACE_ENTRY_SIZE;
 131
 132	return min(len, limit);
 133}
 134
 135static inline void sclp_trace_sccb(int prio, char *id, u32 a, u64 b,
 136				   sclp_cmdw_t cmd, struct sccb_header *sccb,
 137				   bool err)
 138{
 139	sclp_trace(prio, id, a, b, err);
 140	if (sccb) {
 141		sclp_trace_bin(prio + 1, sccb, abbrev_len(cmd, sccb),
 142			       err ? sccb->length : 0);
 143	}
 144}
 145
 146static inline void sclp_trace_evbuf(int prio, char *id, u32 a, u64 b,
 147				    struct evbuf_header *evbuf, bool err)
 148{
 149	sclp_trace(prio, id, a, b, err);
 150	sclp_trace_bin(prio + 1, evbuf,
 151		       min((int)evbuf->length, (int)SCLP_TRACE_EVENT_MAX_SIZE),
 152		       err ? evbuf->length : 0);
 153}
 154
 155static inline void sclp_trace_req(int prio, char *id, struct sclp_req *req,
 156				  bool err)
 157{
 158	struct sccb_header *sccb = req->sccb;
 159	union {
 160		struct {
 161			u16 status;
 162			u16 response;
 163			u16 timeout;
 164			u16 start_count;
 165		};
 166		u64 b;
 167	} summary;
 168
 169	summary.status = req->status;
 170	summary.response = sccb ? sccb->response_code : 0;
 171	summary.timeout = (u16)req->queue_timeout;
 172	summary.start_count = (u16)req->start_count;
 173
 174	sclp_trace(prio, id, __pa(sccb), summary.b, err);
 175}
 176
 177static inline void sclp_trace_register(int prio, char *id, u32 a, u64 b,
 178				       struct sclp_register *reg)
 179{
 180	struct {
 181		u64 receive;
 182		u64 send;
 183	} d;
 184
 185	d.receive = reg->receive_mask;
 186	d.send = reg->send_mask;
 187
 188	sclp_trace(prio, id, a, b, false);
 189	sclp_trace_bin(prio, &d, sizeof(d), 0);
 190}
 191
 192static int __init sclp_setup_console_pages(char *str)
 193{
 194	int pages, rc;
 195
 196	rc = kstrtoint(str, 0, &pages);
 197	if (!rc && pages >= SCLP_CONSOLE_PAGES)
 198		sclp_console_pages = pages;
 199	return 1;
 200}
 201
 202__setup("sclp_con_pages=", sclp_setup_console_pages);
 203
 204static int __init sclp_setup_console_drop(char *str)
 205{
 206	return kstrtobool(str, &sclp_console_drop) == 0;
 207}
 208
 209__setup("sclp_con_drop=", sclp_setup_console_drop);
 210
 211/* Timer for request retries. */
 212static struct timer_list sclp_request_timer;
 213
 214/* Timer for queued requests. */
 215static struct timer_list sclp_queue_timer;
 216
 217/* Internal state: is a request active at the sclp? */
 218static volatile enum sclp_running_state_t {
 219	sclp_running_state_idle,
 220	sclp_running_state_running,
 221	sclp_running_state_reset_pending
 222} sclp_running_state = sclp_running_state_idle;
 223
 224/* Internal state: is a read request pending? */
 225static volatile enum sclp_reading_state_t {
 226	sclp_reading_state_idle,
 227	sclp_reading_state_reading
 228} sclp_reading_state = sclp_reading_state_idle;
 229
 230/* Internal state: is the driver currently serving requests? */
 231static volatile enum sclp_activation_state_t {
 232	sclp_activation_state_active,
 233	sclp_activation_state_deactivating,
 234	sclp_activation_state_inactive,
 235	sclp_activation_state_activating
 236} sclp_activation_state = sclp_activation_state_active;
 237
 238/* Internal state: is an init mask request pending? */
 239static volatile enum sclp_mask_state_t {
 240	sclp_mask_state_idle,
 241	sclp_mask_state_initializing
 242} sclp_mask_state = sclp_mask_state_idle;
 243
 244/* Maximum retry counts */
 245#define SCLP_INIT_RETRY		3
 246#define SCLP_MASK_RETRY		3
 247
 248/* Timeout intervals in seconds.*/
 249#define SCLP_BUSY_INTERVAL	10
 250#define SCLP_RETRY_INTERVAL	30
 251
 252static void sclp_request_timeout(bool force_restart);
 253static void sclp_process_queue(void);
 254static void __sclp_make_read_req(void);
 255static int sclp_init_mask(int calculate);
 256
 257static void
 258__sclp_queue_read_req(void)
 259{
 260	if (sclp_reading_state == sclp_reading_state_idle) {
 261		sclp_reading_state = sclp_reading_state_reading;
 262		__sclp_make_read_req();
 263		/* Add request to head of queue */
 264		list_add(&sclp_read_req.list, &sclp_req_queue);
 265	}
 266}
 267
 268/* Set up request retry timer. Called while sclp_lock is locked. */
 269static inline void
 270__sclp_set_request_timer(unsigned long time, void (*cb)(struct timer_list *))
 271{
 272	timer_delete(&sclp_request_timer);
 273	sclp_request_timer.function = cb;
 274	sclp_request_timer.expires = jiffies + time;
 275	add_timer(&sclp_request_timer);
 276}
 277
 278static void sclp_request_timeout_restart(struct timer_list *unused)
 279{
 280	sclp_request_timeout(true);
 281}
 282
 283static void sclp_request_timeout_normal(struct timer_list *unused)
 284{
 285	sclp_request_timeout(false);
 286}
 287
 288/* Request timeout handler. Restart the request queue. If force_restart,
 289 * force restart of running request. */
 290static void sclp_request_timeout(bool force_restart)
 291{
 292	unsigned long flags;
 293
 294	/* TMO: A timeout occurred (a=force_restart) */
 295	sclp_trace(2, "TMO", force_restart, 0, true);
 296
 297	spin_lock_irqsave(&sclp_lock, flags);
 298	if (force_restart) {
 299		if (sclp_running_state == sclp_running_state_running) {
 300			/* Break running state and queue NOP read event request
 301			 * to get a defined interface state. */
 302			__sclp_queue_read_req();
 303			sclp_running_state = sclp_running_state_idle;
 304		}
 305	} else {
 306		__sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 307					 sclp_request_timeout_normal);
 308	}
 309	spin_unlock_irqrestore(&sclp_lock, flags);
 310	sclp_process_queue();
 311}
 312
 313/*
 314 * Returns the expire value in jiffies of the next pending request timeout,
 315 * if any. Needs to be called with sclp_lock.
 316 */
 317static unsigned long __sclp_req_queue_find_next_timeout(void)
 318{
 319	unsigned long expires_next = 0;
 320	struct sclp_req *req;
 321
 322	list_for_each_entry(req, &sclp_req_queue, list) {
 323		if (!req->queue_expires)
 324			continue;
 325		if (!expires_next ||
 326		   (time_before(req->queue_expires, expires_next)))
 327				expires_next = req->queue_expires;
 328	}
 329	return expires_next;
 330}
 331
 332/*
 333 * Returns expired request, if any, and removes it from the list.
 334 */
 335static struct sclp_req *__sclp_req_queue_remove_expired_req(void)
 336{
 337	unsigned long flags, now;
 338	struct sclp_req *req;
 339
 340	spin_lock_irqsave(&sclp_lock, flags);
 341	now = jiffies;
 342	/* Don't need list_for_each_safe because we break out after list_del */
 343	list_for_each_entry(req, &sclp_req_queue, list) {
 344		if (!req->queue_expires)
 345			continue;
 346		if (time_before_eq(req->queue_expires, now)) {
 347			if (req->status == SCLP_REQ_QUEUED) {
 348				req->status = SCLP_REQ_QUEUED_TIMEOUT;
 349				list_del(&req->list);
 350				goto out;
 351			}
 352		}
 353	}
 354	req = NULL;
 355out:
 356	spin_unlock_irqrestore(&sclp_lock, flags);
 357	return req;
 358}
 359
 360/*
 361 * Timeout handler for queued requests. Removes request from list and
 362 * invokes callback. This timer can be set per request in situations where
 363 * waiting too long would be harmful to the system, e.g. during SE reboot.
 364 */
 365static void sclp_req_queue_timeout(struct timer_list *unused)
 366{
 367	unsigned long flags, expires_next;
 368	struct sclp_req *req;
 369
 370	do {
 371		req = __sclp_req_queue_remove_expired_req();
 372
 373		if (req) {
 374			/* RQTM: Request timed out (a=sccb, b=summary) */
 375			sclp_trace_req(2, "RQTM", req, true);
 376		}
 377
 378		if (req && req->callback)
 379			req->callback(req, req->callback_data);
 380	} while (req);
 381
 382	spin_lock_irqsave(&sclp_lock, flags);
 383	expires_next = __sclp_req_queue_find_next_timeout();
 384	if (expires_next)
 385		mod_timer(&sclp_queue_timer, expires_next);
 386	spin_unlock_irqrestore(&sclp_lock, flags);
 387}
 388
 389static int sclp_service_call_trace(sclp_cmdw_t command, void *sccb)
 390{
 391	static u64 srvc_count;
 392	int rc;
 393
 394	/* SRV1: Service call about to be issued (a=command, b=sccb address) */
 395	sclp_trace_sccb(0, "SRV1", command, (u64)sccb, command, sccb, false);
 396
 397	rc = sclp_service_call(command, sccb);
 398
 399	/* SRV2: Service call was issued (a=rc, b=SRVC sequence number) */
 400	sclp_trace(0, "SRV2", -rc, ++srvc_count, rc != 0);
 401
 402	if (rc == 0)
 403		active_cmd = command;
 404
 405	return rc;
 406}
 407
 408/* Try to start a request. Return zero if the request was successfully
 409 * started or if it will be started at a later time. Return non-zero otherwise.
 410 * Called while sclp_lock is locked. */
 411static int
 412__sclp_start_request(struct sclp_req *req)
 413{
 414	int rc;
 415
 416	if (sclp_running_state != sclp_running_state_idle)
 417		return 0;
 418	timer_delete(&sclp_request_timer);
 419	rc = sclp_service_call_trace(req->command, req->sccb);
 420	req->start_count++;
 421
 422	if (rc == 0) {
 423		/* Successfully started request */
 424		req->status = SCLP_REQ_RUNNING;
 425		sclp_running_state = sclp_running_state_running;
 426		__sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
 427					 sclp_request_timeout_restart);
 428		return 0;
 429	} else if (rc == -EBUSY) {
 430		/* Try again later */
 431		__sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 432					 sclp_request_timeout_normal);
 433		return 0;
 434	}
 435	/* Request failed */
 436	req->status = SCLP_REQ_FAILED;
 437	return rc;
 438}
 439
 440/* Try to start queued requests. */
 441static void
 442sclp_process_queue(void)
 443{
 444	struct sclp_req *req;
 445	int rc;
 446	unsigned long flags;
 447
 448	spin_lock_irqsave(&sclp_lock, flags);
 449	if (sclp_running_state != sclp_running_state_idle) {
 450		spin_unlock_irqrestore(&sclp_lock, flags);
 451		return;
 452	}
 453	timer_delete(&sclp_request_timer);
 454	while (!list_empty(&sclp_req_queue)) {
 455		req = list_entry(sclp_req_queue.next, struct sclp_req, list);
 456		rc = __sclp_start_request(req);
 457		if (rc == 0)
 458			break;
 459		/* Request failed */
 460		if (req->start_count > 1) {
 461			/* Cannot abort already submitted request - could still
 462			 * be active at the SCLP */
 463			__sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
 464						 sclp_request_timeout_normal);
 465			break;
 466		}
 467		/* Post-processing for aborted request */
 468		list_del(&req->list);
 469
 470		/* RQAB: Request aborted (a=sccb, b=summary) */
 471		sclp_trace_req(2, "RQAB", req, true);
 472
 473		if (req->callback) {
 474			spin_unlock_irqrestore(&sclp_lock, flags);
 475			req->callback(req, req->callback_data);
 476			spin_lock_irqsave(&sclp_lock, flags);
 477		}
 478	}
 479	spin_unlock_irqrestore(&sclp_lock, flags);
 480}
 481
 482static int __sclp_can_add_request(struct sclp_req *req)
 483{
 484	if (req == &sclp_init_req)
 485		return 1;
 486	if (sclp_init_state != sclp_init_state_initialized)
 487		return 0;
 488	if (sclp_activation_state != sclp_activation_state_active)
 489		return 0;
 490	return 1;
 491}
 492
 493/* Queue a new request. Return zero on success, non-zero otherwise. */
 494int
 495sclp_add_request(struct sclp_req *req)
 496{
 497	unsigned long flags;
 498	int rc;
 499
 500	spin_lock_irqsave(&sclp_lock, flags);
 501	if (!__sclp_can_add_request(req)) {
 502		spin_unlock_irqrestore(&sclp_lock, flags);
 503		return -EIO;
 504	}
 505
 506	/* RQAD: Request was added (a=sccb, b=caller) */
 507	sclp_trace(2, "RQAD", __pa(req->sccb), _RET_IP_, false);
 508
 509	req->status = SCLP_REQ_QUEUED;
 510	req->start_count = 0;
 511	list_add_tail(&req->list, &sclp_req_queue);
 512	rc = 0;
 513	if (req->queue_timeout) {
 514		req->queue_expires = jiffies + req->queue_timeout * HZ;
 515		if (!timer_pending(&sclp_queue_timer) ||
 516		    time_after(sclp_queue_timer.expires, req->queue_expires))
 517			mod_timer(&sclp_queue_timer, req->queue_expires);
 518	} else
 519		req->queue_expires = 0;
 520	/* Start if request is first in list */
 521	if (sclp_running_state == sclp_running_state_idle &&
 522	    req->list.prev == &sclp_req_queue) {
 523		rc = __sclp_start_request(req);
 524		if (rc)
 525			list_del(&req->list);
 526	}
 527	spin_unlock_irqrestore(&sclp_lock, flags);
 528	return rc;
 529}
 530
 531EXPORT_SYMBOL(sclp_add_request);
 532
 533/* Dispatch events found in request buffer to registered listeners. Return 0
 534 * if all events were dispatched, non-zero otherwise. */
 535static int
 536sclp_dispatch_evbufs(struct sccb_header *sccb)
 537{
 538	unsigned long flags;
 539	struct evbuf_header *evbuf;
 540	struct list_head *l;
 541	struct sclp_register *reg;
 542	int offset;
 543	int rc;
 544
 545	spin_lock_irqsave(&sclp_lock, flags);
 546	rc = 0;
 547	for (offset = sizeof(struct sccb_header); offset < sccb->length;
 548	     offset += evbuf->length) {
 549		evbuf = (struct evbuf_header *) ((addr_t) sccb + offset);
 550		/* Check for malformed hardware response */
 551		if (evbuf->length == 0)
 552			break;
 553		/* Search for event handler */
 554		reg = NULL;
 555		list_for_each(l, &sclp_reg_list) {
 556			reg = list_entry(l, struct sclp_register, list);
 557			if (reg->receive_mask & SCLP_EVTYP_MASK(evbuf->type))
 558				break;
 559			else
 560				reg = NULL;
 561		}
 562
 563		/* EVNT: Event callback (b=receiver) */
 564		sclp_trace_evbuf(2, "EVNT", 0, reg ? (u64)reg->receiver_fn : 0,
 565				 evbuf, !reg);
 566
 567		if (reg && reg->receiver_fn) {
 568			spin_unlock_irqrestore(&sclp_lock, flags);
 569			reg->receiver_fn(evbuf);
 570			spin_lock_irqsave(&sclp_lock, flags);
 571		} else if (reg == NULL)
 572			rc = -EOPNOTSUPP;
 573	}
 574	spin_unlock_irqrestore(&sclp_lock, flags);
 575	return rc;
 576}
 577
 578/* Read event data request callback. */
 579static void
 580sclp_read_cb(struct sclp_req *req, void *data)
 581{
 582	unsigned long flags;
 583	struct sccb_header *sccb;
 584
 585	sccb = (struct sccb_header *) req->sccb;
 586	if (req->status == SCLP_REQ_DONE && (sccb->response_code == 0x20 ||
 587	    sccb->response_code == 0x220))
 588		sclp_dispatch_evbufs(sccb);
 589	spin_lock_irqsave(&sclp_lock, flags);
 590	sclp_reading_state = sclp_reading_state_idle;
 591	spin_unlock_irqrestore(&sclp_lock, flags);
 592}
 593
 594/* Prepare read event data request. Called while sclp_lock is locked. */
 595static void __sclp_make_read_req(void)
 596{
 597	struct sccb_header *sccb;
 598
 599	sccb = (struct sccb_header *) sclp_read_sccb;
 600	clear_page(sccb);
 601	memset(&sclp_read_req, 0, sizeof(struct sclp_req));
 602	sclp_read_req.command = SCLP_CMDW_READ_EVENT_DATA;
 603	sclp_read_req.status = SCLP_REQ_QUEUED;
 604	sclp_read_req.start_count = 0;
 605	sclp_read_req.callback = sclp_read_cb;
 606	sclp_read_req.sccb = sccb;
 607	sccb->length = PAGE_SIZE;
 608	sccb->function_code = 0;
 609	sccb->control_mask[2] = 0x80;
 610}
 611
 612/* Search request list for request with matching sccb. Return request if found,
 613 * NULL otherwise. Called while sclp_lock is locked. */
 614static inline struct sclp_req *
 615__sclp_find_req(u32 sccb)
 616{
 617	struct list_head *l;
 618	struct sclp_req *req;
 619
 620	list_for_each(l, &sclp_req_queue) {
 621		req = list_entry(l, struct sclp_req, list);
 622		if (sccb == __pa(req->sccb))
 623			return req;
 624	}
 625	return NULL;
 626}
 627
 628static bool ok_response(u32 sccb_int, sclp_cmdw_t cmd)
 629{
 630	struct sccb_header *sccb = sclpint_to_sccb(sccb_int);
 631	struct evbuf_header *evbuf;
 632	u16 response;
 633
 634	if (!sccb)
 635		return true;
 636
 637	/* Check SCCB response. */
 638	response = sccb->response_code & 0xff;
 639	if (response != 0x10 && response != 0x20)
 640		return false;
 641
 642	/* Check event-processed flag on outgoing events. */
 643	if (cmd == SCLP_CMDW_WRITE_EVENT_DATA) {
 644		evbuf = (struct evbuf_header *)(sccb + 1);
 645		if (!(evbuf->flags & 0x80))
 646			return false;
 647	}
 648
 649	return true;
 650}
 651
 652/* Handler for external interruption. Perform request post-processing.
 653 * Prepare read event data request if necessary. Start processing of next
 654 * request on queue. */
 655static void sclp_interrupt_handler(struct ext_code ext_code,
 656				   unsigned int param32, unsigned long param64)
 657{
 658	struct sclp_req *req;
 659	u32 finished_sccb;
 660	u32 evbuf_pending;
 661
 662	inc_irq_stat(IRQEXT_SCP);
 663	spin_lock(&sclp_lock);
 664	finished_sccb = param32 & 0xfffffff8;
 665	evbuf_pending = param32 & 0x3;
 666
 667	/* INT: Interrupt received (a=intparm, b=cmd) */
 668	sclp_trace_sccb(0, "INT", param32, active_cmd, active_cmd,
 669			sclpint_to_sccb(finished_sccb),
 670			!ok_response(finished_sccb, active_cmd));
 671
 672	if (finished_sccb) {
 673		timer_delete(&sclp_request_timer);
 674		sclp_running_state = sclp_running_state_reset_pending;
 675		req = __sclp_find_req(finished_sccb);
 676		if (req) {
 677			/* Request post-processing */
 678			list_del(&req->list);
 679			req->status = SCLP_REQ_DONE;
 680
 681			/* RQOK: Request success (a=sccb, b=summary) */
 682			sclp_trace_req(2, "RQOK", req, false);
 683
 684			if (req->callback) {
 685				spin_unlock(&sclp_lock);
 686				req->callback(req, req->callback_data);
 687				spin_lock(&sclp_lock);
 688			}
 689		} else {
 690			/* UNEX: Unexpected SCCB completion (a=sccb address) */
 691			sclp_trace(0, "UNEX", finished_sccb, 0, true);
 692		}
 693		sclp_running_state = sclp_running_state_idle;
 694		active_cmd = 0;
 695	}
 696	if (evbuf_pending &&
 697	    sclp_activation_state == sclp_activation_state_active)
 698		__sclp_queue_read_req();
 699	spin_unlock(&sclp_lock);
 700	sclp_process_queue();
 701}
 702
 703/* Convert interval in jiffies to TOD ticks. */
 704static inline u64
 705sclp_tod_from_jiffies(unsigned long jiffies)
 706{
 707	return (u64) (jiffies / HZ) << 32;
 708}
 709
 710/* Wait until a currently running request finished. Note: while this function
 711 * is running, no timers are served on the calling CPU. */
 712void
 713sclp_sync_wait(void)
 714{
 715	unsigned long long old_tick;
 716	struct ctlreg cr0, cr0_sync;
 717	unsigned long flags;
 718	static u64 sync_count;
 719	u64 timeout;
 720	int irq_context;
 721
 722	/* SYN1: Synchronous wait start (a=runstate, b=sync count) */
 723	sclp_trace(4, "SYN1", sclp_running_state, ++sync_count, false);
 724
 725	/* We'll be disabling timer interrupts, so we need a custom timeout
 726	 * mechanism */
 727	timeout = 0;
 728	if (timer_pending(&sclp_request_timer)) {
 729		/* Get timeout TOD value */
 730		timeout = get_tod_clock_monotonic() +
 731			  sclp_tod_from_jiffies(sclp_request_timer.expires -
 732						jiffies);
 733	}
 734	local_irq_save(flags);
 735	/* Prevent bottom half from executing once we force interrupts open */
 736	irq_context = in_interrupt();
 737	if (!irq_context)
 738		local_bh_disable();
 739	/* Enable service-signal interruption, disable timer interrupts */
 740	old_tick = local_tick_disable();
 741	trace_hardirqs_on();
 742	local_ctl_store(0, &cr0);
 743	cr0_sync.val = cr0.val & ~CR0_IRQ_SUBCLASS_MASK;
 744	cr0_sync.val |= 1UL << (63 - 54);
 745	local_ctl_load(0, &cr0_sync);
 746	arch_local_irq_enable_external();
 747	/* Loop until driver state indicates finished request */
 748	while (sclp_running_state != sclp_running_state_idle) {
 749		/* Check for expired request timer */
 750		if (get_tod_clock_monotonic() > timeout && timer_delete(&sclp_request_timer))
 751			sclp_request_timer.function(&sclp_request_timer);
 752		cpu_relax();
 753	}
 754	local_irq_disable();
 755	local_ctl_load(0, &cr0);
 756	if (!irq_context)
 757		_local_bh_enable();
 758	local_tick_enable(old_tick);
 759	local_irq_restore(flags);
 760
 761	/* SYN2: Synchronous wait end (a=runstate, b=sync_count) */
 762	sclp_trace(4, "SYN2", sclp_running_state, sync_count, false);
 763}
 764EXPORT_SYMBOL(sclp_sync_wait);
 765
 766/* Dispatch changes in send and receive mask to registered listeners. */
 767static void
 768sclp_dispatch_state_change(void)
 769{
 770	struct list_head *l;
 771	struct sclp_register *reg;
 772	unsigned long flags;
 773	sccb_mask_t receive_mask;
 774	sccb_mask_t send_mask;
 775
 776	do {
 777		spin_lock_irqsave(&sclp_lock, flags);
 778		reg = NULL;
 779		list_for_each(l, &sclp_reg_list) {
 780			reg = list_entry(l, struct sclp_register, list);
 781			receive_mask = reg->send_mask & sclp_receive_mask;
 782			send_mask = reg->receive_mask & sclp_send_mask;
 783			if (reg->sclp_receive_mask != receive_mask ||
 784			    reg->sclp_send_mask != send_mask) {
 785				reg->sclp_receive_mask = receive_mask;
 786				reg->sclp_send_mask = send_mask;
 787				break;
 788			} else
 789				reg = NULL;
 790		}
 791		spin_unlock_irqrestore(&sclp_lock, flags);
 792		if (reg && reg->state_change_fn) {
 793			/* STCG: State-change callback (b=callback) */
 794			sclp_trace(2, "STCG", 0, (u64)reg->state_change_fn,
 795				   false);
 796
 797			reg->state_change_fn(reg);
 798		}
 799	} while (reg);
 800}
 801
 802struct sclp_statechangebuf {
 803	struct evbuf_header	header;
 804	u8		validity_sclp_active_facility_mask : 1;
 805	u8		validity_sclp_receive_mask : 1;
 806	u8		validity_sclp_send_mask : 1;
 807	u8		validity_read_data_function_mask : 1;
 808	u16		_zeros : 12;
 809	u16		mask_length;
 810	u64		sclp_active_facility_mask;
 811	u8		masks[2 * 1021 + 4];	/* variable length */
 812	/*
 813	 * u8		sclp_receive_mask[mask_length];
 814	 * u8		sclp_send_mask[mask_length];
 815	 * u32		read_data_function_mask;
 816	 */
 817} __attribute__((packed));
 818
 819
 820/* State change event callback. Inform listeners of changes. */
 821static void
 822sclp_state_change_cb(struct evbuf_header *evbuf)
 823{
 824	unsigned long flags;
 825	struct sclp_statechangebuf *scbuf;
 826
 827	BUILD_BUG_ON(sizeof(struct sclp_statechangebuf) > PAGE_SIZE);
 828
 829	scbuf = (struct sclp_statechangebuf *) evbuf;
 830	spin_lock_irqsave(&sclp_lock, flags);
 831	if (scbuf->validity_sclp_receive_mask)
 832		sclp_receive_mask = sccb_get_recv_mask(scbuf);
 833	if (scbuf->validity_sclp_send_mask)
 834		sclp_send_mask = sccb_get_send_mask(scbuf);
 835	spin_unlock_irqrestore(&sclp_lock, flags);
 836	if (scbuf->validity_sclp_active_facility_mask)
 837		sclp.facilities = scbuf->sclp_active_facility_mask;
 838	sclp_dispatch_state_change();
 839}
 840
 841static struct sclp_register sclp_state_change_event = {
 842	.receive_mask = EVTYP_STATECHANGE_MASK,
 843	.receiver_fn = sclp_state_change_cb
 844};
 845
 846/* Calculate receive and send mask of currently registered listeners.
 847 * Called while sclp_lock is locked. */
 848static inline void
 849__sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask)
 850{
 851	struct list_head *l;
 852	struct sclp_register *t;
 853
 854	*receive_mask = 0;
 855	*send_mask = 0;
 856	list_for_each(l, &sclp_reg_list) {
 857		t = list_entry(l, struct sclp_register, list);
 858		*receive_mask |= t->receive_mask;
 859		*send_mask |= t->send_mask;
 860	}
 861}
 862
 863/* Register event listener. Return 0 on success, non-zero otherwise. */
 864int
 865sclp_register(struct sclp_register *reg)
 866{
 867	unsigned long flags;
 868	sccb_mask_t receive_mask;
 869	sccb_mask_t send_mask;
 870	int rc;
 871
 872	/* REG: Event listener registered (b=caller) */
 873	sclp_trace_register(2, "REG", 0, _RET_IP_, reg);
 874
 875	rc = sclp_init();
 876	if (rc)
 877		return rc;
 878	spin_lock_irqsave(&sclp_lock, flags);
 879	/* Check event mask for collisions */
 880	__sclp_get_mask(&receive_mask, &send_mask);
 881	if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) {
 882		spin_unlock_irqrestore(&sclp_lock, flags);
 883		return -EBUSY;
 884	}
 885	/* Trigger initial state change callback */
 886	reg->sclp_receive_mask = 0;
 887	reg->sclp_send_mask = 0;
 888	list_add(&reg->list, &sclp_reg_list);
 889	spin_unlock_irqrestore(&sclp_lock, flags);
 890	rc = sclp_init_mask(1);
 891	if (rc) {
 892		spin_lock_irqsave(&sclp_lock, flags);
 893		list_del(&reg->list);
 894		spin_unlock_irqrestore(&sclp_lock, flags);
 895	}
 896	return rc;
 897}
 898
 899EXPORT_SYMBOL(sclp_register);
 900
 901/* Unregister event listener. */
 902void
 903sclp_unregister(struct sclp_register *reg)
 904{
 905	unsigned long flags;
 906
 907	/* UREG: Event listener unregistered (b=caller) */
 908	sclp_trace_register(2, "UREG", 0, _RET_IP_, reg);
 909
 910	spin_lock_irqsave(&sclp_lock, flags);
 911	list_del(&reg->list);
 912	spin_unlock_irqrestore(&sclp_lock, flags);
 913	sclp_init_mask(1);
 914}
 915
 916EXPORT_SYMBOL(sclp_unregister);
 917
 918/* Remove event buffers which are marked processed. Return the number of
 919 * remaining event buffers. */
 920int
 921sclp_remove_processed(struct sccb_header *sccb)
 922{
 923	struct evbuf_header *evbuf;
 924	int unprocessed;
 925	u16 remaining;
 926
 927	evbuf = (struct evbuf_header *) (sccb + 1);
 928	unprocessed = 0;
 929	remaining = sccb->length - sizeof(struct sccb_header);
 930	while (remaining > 0) {
 931		remaining -= evbuf->length;
 932		if (evbuf->flags & 0x80) {
 933			sccb->length -= evbuf->length;
 934			memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length),
 935			       remaining);
 936		} else {
 937			unprocessed++;
 938			evbuf = (struct evbuf_header *)
 939					((addr_t) evbuf + evbuf->length);
 940		}
 941	}
 942	return unprocessed;
 943}
 944
 945EXPORT_SYMBOL(sclp_remove_processed);
 946
 947/* Prepare init mask request. Called while sclp_lock is locked. */
 948static inline void
 949__sclp_make_init_req(sccb_mask_t receive_mask, sccb_mask_t send_mask)
 950{
 951	struct init_sccb *sccb = sclp_init_sccb;
 952
 953	clear_page(sccb);
 954	memset(&sclp_init_req, 0, sizeof(struct sclp_req));
 955	sclp_init_req.command = SCLP_CMDW_WRITE_EVENT_MASK;
 956	sclp_init_req.status = SCLP_REQ_FILLED;
 957	sclp_init_req.start_count = 0;
 958	sclp_init_req.callback = NULL;
 959	sclp_init_req.callback_data = NULL;
 960	sclp_init_req.sccb = sccb;
 961	sccb->header.length = sizeof(*sccb);
 962	if (sclp_mask_compat_mode)
 963		sccb->mask_length = SCLP_MASK_SIZE_COMPAT;
 964	else
 965		sccb->mask_length = sizeof(sccb_mask_t);
 966	sccb_set_recv_mask(sccb, receive_mask);
 967	sccb_set_send_mask(sccb, send_mask);
 968	sccb_set_sclp_recv_mask(sccb, 0);
 969	sccb_set_sclp_send_mask(sccb, 0);
 970}
 971
 972/* Start init mask request. If calculate is non-zero, calculate the mask as
 973 * requested by registered listeners. Use zero mask otherwise. Return 0 on
 974 * success, non-zero otherwise. */
 975static int
 976sclp_init_mask(int calculate)
 977{
 978	unsigned long flags;
 979	struct init_sccb *sccb = sclp_init_sccb;
 980	sccb_mask_t receive_mask;
 981	sccb_mask_t send_mask;
 982	int retry;
 983	int rc;
 984	unsigned long wait;
 985
 986	spin_lock_irqsave(&sclp_lock, flags);
 987	/* Check if interface is in appropriate state */
 988	if (sclp_mask_state != sclp_mask_state_idle) {
 989		spin_unlock_irqrestore(&sclp_lock, flags);
 990		return -EBUSY;
 991	}
 992	if (sclp_activation_state == sclp_activation_state_inactive) {
 993		spin_unlock_irqrestore(&sclp_lock, flags);
 994		return -EINVAL;
 995	}
 996	sclp_mask_state = sclp_mask_state_initializing;
 997	/* Determine mask */
 998	if (calculate)
 999		__sclp_get_mask(&receive_mask, &send_mask);
1000	else {
1001		receive_mask = 0;
1002		send_mask = 0;
1003	}
1004	rc = -EIO;
1005	for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) {
1006		/* Prepare request */
1007		__sclp_make_init_req(receive_mask, send_mask);
1008		spin_unlock_irqrestore(&sclp_lock, flags);
1009		if (sclp_add_request(&sclp_init_req)) {
1010			/* Try again later */
1011			wait = jiffies + SCLP_BUSY_INTERVAL * HZ;
1012			while (time_before(jiffies, wait))
1013				sclp_sync_wait();
1014			spin_lock_irqsave(&sclp_lock, flags);
1015			continue;
1016		}
1017		while (sclp_init_req.status != SCLP_REQ_DONE &&
1018		       sclp_init_req.status != SCLP_REQ_FAILED)
1019			sclp_sync_wait();
1020		spin_lock_irqsave(&sclp_lock, flags);
1021		if (sclp_init_req.status == SCLP_REQ_DONE &&
1022		    sccb->header.response_code == 0x20) {
1023			/* Successful request */
1024			if (calculate) {
1025				sclp_receive_mask = sccb_get_sclp_recv_mask(sccb);
1026				sclp_send_mask = sccb_get_sclp_send_mask(sccb);
1027			} else {
1028				sclp_receive_mask = 0;
1029				sclp_send_mask = 0;
1030			}
1031			spin_unlock_irqrestore(&sclp_lock, flags);
1032			sclp_dispatch_state_change();
1033			spin_lock_irqsave(&sclp_lock, flags);
1034			rc = 0;
1035			break;
1036		}
1037	}
1038	sclp_mask_state = sclp_mask_state_idle;
1039	spin_unlock_irqrestore(&sclp_lock, flags);
1040	return rc;
1041}
1042
1043/* Deactivate SCLP interface. On success, new requests will be rejected,
1044 * events will no longer be dispatched. Return 0 on success, non-zero
1045 * otherwise. */
1046int
1047sclp_deactivate(void)
1048{
1049	unsigned long flags;
1050	int rc;
1051
1052	spin_lock_irqsave(&sclp_lock, flags);
1053	/* Deactivate can only be called when active */
1054	if (sclp_activation_state != sclp_activation_state_active) {
1055		spin_unlock_irqrestore(&sclp_lock, flags);
1056		return -EINVAL;
1057	}
1058	sclp_activation_state = sclp_activation_state_deactivating;
1059	spin_unlock_irqrestore(&sclp_lock, flags);
1060	rc = sclp_init_mask(0);
1061	spin_lock_irqsave(&sclp_lock, flags);
1062	if (rc == 0)
1063		sclp_activation_state = sclp_activation_state_inactive;
1064	else
1065		sclp_activation_state = sclp_activation_state_active;
1066	spin_unlock_irqrestore(&sclp_lock, flags);
1067	return rc;
1068}
1069
1070EXPORT_SYMBOL(sclp_deactivate);
1071
1072/* Reactivate SCLP interface after sclp_deactivate. On success, new
1073 * requests will be accepted, events will be dispatched again. Return 0 on
1074 * success, non-zero otherwise. */
1075int
1076sclp_reactivate(void)
1077{
1078	unsigned long flags;
1079	int rc;
1080
1081	spin_lock_irqsave(&sclp_lock, flags);
1082	/* Reactivate can only be called when inactive */
1083	if (sclp_activation_state != sclp_activation_state_inactive) {
1084		spin_unlock_irqrestore(&sclp_lock, flags);
1085		return -EINVAL;
1086	}
1087	sclp_activation_state = sclp_activation_state_activating;
1088	spin_unlock_irqrestore(&sclp_lock, flags);
1089	rc = sclp_init_mask(1);
1090	spin_lock_irqsave(&sclp_lock, flags);
1091	if (rc == 0)
1092		sclp_activation_state = sclp_activation_state_active;
1093	else
1094		sclp_activation_state = sclp_activation_state_inactive;
1095	spin_unlock_irqrestore(&sclp_lock, flags);
1096	return rc;
1097}
1098
1099EXPORT_SYMBOL(sclp_reactivate);
1100
1101/* Handler for external interruption used during initialization. Modify
1102 * request state to done. */
1103static void sclp_check_handler(struct ext_code ext_code,
1104			       unsigned int param32, unsigned long param64)
1105{
1106	u32 finished_sccb;
1107
1108	inc_irq_stat(IRQEXT_SCP);
1109	finished_sccb = param32 & 0xfffffff8;
1110	/* Is this the interrupt we are waiting for? */
1111	if (finished_sccb == 0)
1112		return;
1113	if (finished_sccb != __pa(sclp_init_sccb))
1114		panic("sclp: unsolicited interrupt for buffer at 0x%x\n",
1115		      finished_sccb);
1116	spin_lock(&sclp_lock);
1117	if (sclp_running_state == sclp_running_state_running) {
1118		sclp_init_req.status = SCLP_REQ_DONE;
1119		sclp_running_state = sclp_running_state_idle;
1120	}
1121	spin_unlock(&sclp_lock);
1122}
1123
1124/* Initial init mask request timed out. Modify request state to failed. */
1125static void
1126sclp_check_timeout(struct timer_list *unused)
1127{
1128	unsigned long flags;
1129
1130	spin_lock_irqsave(&sclp_lock, flags);
1131	if (sclp_running_state == sclp_running_state_running) {
1132		sclp_init_req.status = SCLP_REQ_FAILED;
1133		sclp_running_state = sclp_running_state_idle;
1134	}
1135	spin_unlock_irqrestore(&sclp_lock, flags);
1136}
1137
1138/* Perform a check of the SCLP interface. Return zero if the interface is
1139 * available and there are no pending requests from a previous instance.
1140 * Return non-zero otherwise. */
1141static int
1142sclp_check_interface(void)
1143{
1144	struct init_sccb *sccb;
1145	unsigned long flags;
1146	int retry;
1147	int rc;
1148
1149	spin_lock_irqsave(&sclp_lock, flags);
1150	/* Prepare init mask command */
1151	rc = register_external_irq(EXT_IRQ_SERVICE_SIG, sclp_check_handler);
1152	if (rc) {
1153		spin_unlock_irqrestore(&sclp_lock, flags);
1154		return rc;
1155	}
1156	for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) {
1157		__sclp_make_init_req(0, 0);
1158		sccb = (struct init_sccb *) sclp_init_req.sccb;
1159		rc = sclp_service_call_trace(sclp_init_req.command, sccb);
1160		if (rc == -EIO)
1161			break;
1162		sclp_init_req.status = SCLP_REQ_RUNNING;
1163		sclp_running_state = sclp_running_state_running;
1164		__sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
1165					 sclp_check_timeout);
1166		spin_unlock_irqrestore(&sclp_lock, flags);
1167		/* Enable service-signal interruption - needs to happen
1168		 * with IRQs enabled. */
1169		irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
1170		/* Wait for signal from interrupt or timeout */
1171		sclp_sync_wait();
1172		/* Disable service-signal interruption - needs to happen
1173		 * with IRQs enabled. */
1174		irq_subclass_unregister(IRQ_SUBCLASS_SERVICE_SIGNAL);
1175		spin_lock_irqsave(&sclp_lock, flags);
1176		timer_delete(&sclp_request_timer);
1177		rc = -EBUSY;
1178		if (sclp_init_req.status == SCLP_REQ_DONE) {
1179			if (sccb->header.response_code == 0x20) {
1180				rc = 0;
1181				break;
1182			} else if (sccb->header.response_code == 0x74f0) {
1183				if (!sclp_mask_compat_mode) {
1184					sclp_mask_compat_mode = true;
1185					retry = 0;
1186				}
1187			}
1188		}
1189	}
1190	unregister_external_irq(EXT_IRQ_SERVICE_SIG, sclp_check_handler);
1191	spin_unlock_irqrestore(&sclp_lock, flags);
1192	return rc;
1193}
1194
1195/* Reboot event handler. Reset send and receive mask to prevent pending SCLP
1196 * events from interfering with rebooted system. */
1197static int
1198sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
1199{
1200	sclp_deactivate();
1201	return NOTIFY_DONE;
1202}
1203
1204static struct notifier_block sclp_reboot_notifier = {
1205	.notifier_call = sclp_reboot_event,
1206	.priority      = INT_MIN,
1207};
1208
1209static ssize_t con_pages_show(struct device_driver *dev, char *buf)
1210{
1211	return sysfs_emit(buf, "%i\n", sclp_console_pages);
1212}
1213
1214static DRIVER_ATTR_RO(con_pages);
1215
1216static ssize_t con_drop_store(struct device_driver *dev, const char *buf, size_t count)
1217{
1218	int rc;
1219
1220	rc = kstrtobool(buf, &sclp_console_drop);
1221	return rc ?: count;
1222}
1223
1224static ssize_t con_drop_show(struct device_driver *dev, char *buf)
1225{
1226	return sysfs_emit(buf, "%i\n", sclp_console_drop);
1227}
1228
1229static DRIVER_ATTR_RW(con_drop);
1230
1231static ssize_t con_full_show(struct device_driver *dev, char *buf)
1232{
1233	return sysfs_emit(buf, "%lu\n", sclp_console_full);
1234}
1235
1236static DRIVER_ATTR_RO(con_full);
1237
1238static struct attribute *sclp_drv_attrs[] = {
1239	&driver_attr_con_pages.attr,
1240	&driver_attr_con_drop.attr,
1241	&driver_attr_con_full.attr,
1242	NULL,
1243};
1244static struct attribute_group sclp_drv_attr_group = {
1245	.attrs = sclp_drv_attrs,
1246};
1247static const struct attribute_group *sclp_drv_attr_groups[] = {
1248	&sclp_drv_attr_group,
1249	NULL,
1250};
1251
1252static struct platform_driver sclp_pdrv = {
1253	.driver = {
1254		.name	= "sclp",
1255		.groups = sclp_drv_attr_groups,
1256	},
1257};
1258
1259/* Initialize SCLP driver. Return zero if driver is operational, non-zero
1260 * otherwise. */
1261int sclp_init(void)
1262{
1263	unsigned long flags;
1264	int rc = 0;
1265
1266	spin_lock_irqsave(&sclp_lock, flags);
1267	/* Check for previous or running initialization */
1268	if (sclp_init_state != sclp_init_state_uninitialized)
1269		goto fail_unlock;
1270	sclp_init_state = sclp_init_state_initializing;
1271	sclp_read_sccb = (void *) __get_free_page(GFP_ATOMIC | GFP_DMA);
1272	sclp_init_sccb = (void *) __get_free_page(GFP_ATOMIC | GFP_DMA);
1273	BUG_ON(!sclp_read_sccb || !sclp_init_sccb);
1274	/* Set up variables */
1275	list_add(&sclp_state_change_event.list, &sclp_reg_list);
1276	timer_setup(&sclp_request_timer, NULL, 0);
1277	timer_setup(&sclp_queue_timer, sclp_req_queue_timeout, 0);
1278	/* Check interface */
1279	spin_unlock_irqrestore(&sclp_lock, flags);
1280	rc = sclp_check_interface();
1281	spin_lock_irqsave(&sclp_lock, flags);
1282	if (rc)
1283		goto fail_init_state_uninitialized;
1284	/* Register reboot handler */
1285	rc = register_reboot_notifier(&sclp_reboot_notifier);
1286	if (rc)
1287		goto fail_init_state_uninitialized;
1288	/* Register interrupt handler */
1289	rc = register_external_irq(EXT_IRQ_SERVICE_SIG, sclp_interrupt_handler);
1290	if (rc)
1291		goto fail_unregister_reboot_notifier;
1292	sclp_init_state = sclp_init_state_initialized;
1293	spin_unlock_irqrestore(&sclp_lock, flags);
1294	/* Enable service-signal external interruption - needs to happen with
1295	 * IRQs enabled. */
1296	irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
1297	sclp_init_mask(1);
1298	return 0;
1299
1300fail_unregister_reboot_notifier:
1301	unregister_reboot_notifier(&sclp_reboot_notifier);
1302fail_init_state_uninitialized:
1303	list_del(&sclp_state_change_event.list);
1304	sclp_init_state = sclp_init_state_uninitialized;
1305	free_page((unsigned long) sclp_read_sccb);
1306	free_page((unsigned long) sclp_init_sccb);
1307fail_unlock:
1308	spin_unlock_irqrestore(&sclp_lock, flags);
1309	return rc;
1310}
1311
1312static __init int sclp_initcall(void)
1313{
1314	return platform_driver_register(&sclp_pdrv);
1315}
1316
1317arch_initcall(sclp_initcall);