device.c

   1// SPDX-License-Identifier: GPL-1.0+
   2/*
   3 *  bus driver for ccw devices
   4 *
   5 *    Copyright IBM Corp. 2002, 2008
   6 *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
   7 *		 Cornelia Huck (cornelia.huck@de.ibm.com)
   8 *		 Martin Schwidefsky (schwidefsky@de.ibm.com)
   9 */
  10
  11#define pr_fmt(fmt) "cio: " fmt
  12
  13#include <linux/export.h>
  14#include <linux/init.h>
  15#include <linux/spinlock.h>
  16#include <linux/errno.h>
  17#include <linux/err.h>
  18#include <linux/slab.h>
  19#include <linux/list.h>
  20#include <linux/device.h>
  21#include <linux/workqueue.h>
  22#include <linux/delay.h>
  23#include <linux/timer.h>
  24#include <linux/kernel_stat.h>
  25#include <linux/sched/signal.h>
  26#include <linux/dma-mapping.h>
  27
  28#include <asm/ccwdev.h>
  29#include <asm/cio.h>
  30#include <asm/param.h>		/* HZ */
  31#include <asm/cmb.h>
  32#include <asm/isc.h>
  33
  34#include "chp.h"
  35#include "cio.h"
  36#include "cio_debug.h"
  37#include "css.h"
  38#include "device.h"
  39#include "ioasm.h"
  40#include "io_sch.h"
  41#include "blacklist.h"
  42#include "chsc.h"
  43
  44static struct timer_list recovery_timer;
  45static DEFINE_SPINLOCK(recovery_lock);
  46static int recovery_phase;
  47static const unsigned long recovery_delay[] = { 3, 30, 300 };
  48
  49static atomic_t ccw_device_init_count = ATOMIC_INIT(0);
  50static DECLARE_WAIT_QUEUE_HEAD(ccw_device_init_wq);
  51static const struct bus_type ccw_bus_type;
  52
  53/******************* bus type handling ***********************/
  54
  55/* The Linux driver model distinguishes between a bus type and
  56 * the bus itself. Of course we only have one channel
  57 * subsystem driver and one channel system per machine, but
  58 * we still use the abstraction. T.R. says it's a good idea. */
  59static int
  60ccw_bus_match (struct device * dev, const struct device_driver * drv)
  61{
  62	struct ccw_device *cdev = to_ccwdev(dev);
  63	const struct ccw_driver *cdrv = to_ccwdrv(drv);
  64	const struct ccw_device_id *ids = cdrv->ids, *found;
  65
  66	if (!ids)
  67		return 0;
  68
  69	found = ccw_device_id_match(ids, &cdev->id);
  70	if (!found)
  71		return 0;
  72
  73	cdev->id.driver_info = found->driver_info;
  74
  75	return 1;
  76}
  77
  78/* Store modalias string delimited by prefix/suffix string into buffer with
  79 * specified size. Return length of resulting string (excluding trailing '\0')
  80 * even if string doesn't fit buffer (snprintf semantics). */
  81static int snprint_alias(char *buf, size_t size,
  82			 const struct ccw_device_id *id, const char *suffix)
  83{
  84	int len;
  85
  86	len = snprintf(buf, size, "ccw:t%04Xm%02X", id->cu_type, id->cu_model);
  87	if (len > size)
  88		return len;
  89	buf += len;
  90	size -= len;
  91
  92	if (id->dev_type != 0)
  93		len += snprintf(buf, size, "dt%04Xdm%02X%s", id->dev_type,
  94				id->dev_model, suffix);
  95	else
  96		len += snprintf(buf, size, "dtdm%s", suffix);
  97
  98	return len;
  99}
 100
 101/* Set up environment variables for ccw device uevent. Return 0 on success,
 102 * non-zero otherwise. */
 103static int ccw_uevent(const struct device *dev, struct kobj_uevent_env *env)
 104{
 105	const struct ccw_device *cdev = to_ccwdev(dev);
 106	const struct ccw_device_id *id = &(cdev->id);
 107	int ret;
 108	char modalias_buf[30];
 109
 110	/* CU_TYPE= */
 111	ret = add_uevent_var(env, "CU_TYPE=%04X", id->cu_type);
 112	if (ret)
 113		return ret;
 114
 115	/* CU_MODEL= */
 116	ret = add_uevent_var(env, "CU_MODEL=%02X", id->cu_model);
 117	if (ret)
 118		return ret;
 119
 120	/* The next two can be zero, that's ok for us */
 121	/* DEV_TYPE= */
 122	ret = add_uevent_var(env, "DEV_TYPE=%04X", id->dev_type);
 123	if (ret)
 124		return ret;
 125
 126	/* DEV_MODEL= */
 127	ret = add_uevent_var(env, "DEV_MODEL=%02X", id->dev_model);
 128	if (ret)
 129		return ret;
 130
 131	/* MODALIAS=  */
 132	snprint_alias(modalias_buf, sizeof(modalias_buf), id, "");
 133	ret = add_uevent_var(env, "MODALIAS=%s", modalias_buf);
 134	return ret;
 135}
 136
 137static void io_subchannel_irq(struct subchannel *);
 138static int io_subchannel_probe(struct subchannel *);
 139static void io_subchannel_remove(struct subchannel *);
 140static void io_subchannel_shutdown(struct subchannel *);
 141static int io_subchannel_sch_event(struct subchannel *, int);
 142static int io_subchannel_chp_event(struct subchannel *, struct chp_link *,
 143				   int);
 144static void recovery_func(struct timer_list *unused);
 145
 146static struct css_device_id io_subchannel_ids[] = {
 147	{ .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
 148	{ /* end of list */ },
 149};
 150
 151static int io_subchannel_settle(void)
 152{
 153	int ret;
 154
 155	ret = wait_event_interruptible(ccw_device_init_wq,
 156				atomic_read(&ccw_device_init_count) == 0);
 157	if (ret)
 158		return -EINTR;
 159	flush_workqueue(cio_work_q);
 160	return 0;
 161}
 162
 163static struct css_driver io_subchannel_driver = {
 164	.drv = {
 165		.owner = THIS_MODULE,
 166		.name = "io_subchannel",
 167	},
 168	.subchannel_type = io_subchannel_ids,
 169	.irq = io_subchannel_irq,
 170	.sch_event = io_subchannel_sch_event,
 171	.chp_event = io_subchannel_chp_event,
 172	.probe = io_subchannel_probe,
 173	.remove = io_subchannel_remove,
 174	.shutdown = io_subchannel_shutdown,
 175	.settle = io_subchannel_settle,
 176};
 177
 178int __init io_subchannel_init(void)
 179{
 180	int ret;
 181
 182	timer_setup(&recovery_timer, recovery_func, 0);
 183	ret = bus_register(&ccw_bus_type);
 184	if (ret)
 185		return ret;
 186	ret = css_driver_register(&io_subchannel_driver);
 187	if (ret)
 188		bus_unregister(&ccw_bus_type);
 189
 190	return ret;
 191}
 192
 193
 194/************************ device handling **************************/
 195
 196static ssize_t
 197devtype_show (struct device *dev, struct device_attribute *attr, char *buf)
 198{
 199	struct ccw_device *cdev = to_ccwdev(dev);
 200	struct ccw_device_id *id = &(cdev->id);
 201
 202	if (id->dev_type != 0)
 203		return sysfs_emit(buf, "%04x/%02x\n", id->dev_type, id->dev_model);
 204	else
 205		return sysfs_emit(buf, "n/a\n");
 206}
 207
 208static ssize_t
 209cutype_show (struct device *dev, struct device_attribute *attr, char *buf)
 210{
 211	struct ccw_device *cdev = to_ccwdev(dev);
 212	struct ccw_device_id *id = &(cdev->id);
 213
 214	return sysfs_emit(buf, "%04x/%02x\n", id->cu_type, id->cu_model);
 215}
 216
 217static ssize_t
 218modalias_show (struct device *dev, struct device_attribute *attr, char *buf)
 219{
 220	struct ccw_device *cdev = to_ccwdev(dev);
 221	struct ccw_device_id *id = &(cdev->id);
 222	int len;
 223
 224	len = snprint_alias(buf, PAGE_SIZE, id, "\n");
 225
 226	return len > PAGE_SIZE ? PAGE_SIZE : len;
 227}
 228
 229static ssize_t
 230online_show (struct device *dev, struct device_attribute *attr, char *buf)
 231{
 232	struct ccw_device *cdev = to_ccwdev(dev);
 233
 234	return sysfs_emit(buf, cdev->online ? "1\n" : "0\n");
 235}
 236
 237int ccw_device_is_orphan(struct ccw_device *cdev)
 238{
 239	return sch_is_pseudo_sch(to_subchannel(cdev->dev.parent));
 240}
 241
 242static void ccw_device_unregister(struct ccw_device *cdev)
 243{
 244	mutex_lock(&cdev->reg_mutex);
 245	if (device_is_registered(&cdev->dev)) {
 246		/* Undo device_add(). */
 247		device_del(&cdev->dev);
 248	}
 249	mutex_unlock(&cdev->reg_mutex);
 250
 251	if (cdev->private->flags.initialized) {
 252		cdev->private->flags.initialized = 0;
 253		/* Release reference from device_initialize(). */
 254		put_device(&cdev->dev);
 255	}
 256}
 257
 258static void io_subchannel_quiesce(struct subchannel *);
 259
 260/**
 261 * ccw_device_set_offline() - disable a ccw device for I/O
 262 * @cdev: target ccw device
 263 *
 264 * This function calls the driver's set_offline() function for @cdev, if
 265 * given, and then disables @cdev.
 266 * Returns:
 267 *   %0 on success and a negative error value on failure.
 268 * Context:
 269 *  enabled, ccw device lock not held
 270 */
 271int ccw_device_set_offline(struct ccw_device *cdev)
 272{
 273	struct subchannel *sch;
 274	int ret, state;
 275
 276	if (!cdev)
 277		return -ENODEV;
 278	if (!cdev->online || !cdev->drv)
 279		return -EINVAL;
 280
 281	if (cdev->drv->set_offline) {
 282		ret = cdev->drv->set_offline(cdev);
 283		if (ret != 0)
 284			return ret;
 285	}
 286	spin_lock_irq(cdev->ccwlock);
 287	sch = to_subchannel(cdev->dev.parent);
 288	cdev->online = 0;
 289	/* Wait until a final state or DISCONNECTED is reached */
 290	while (!dev_fsm_final_state(cdev) &&
 291	       cdev->private->state != DEV_STATE_DISCONNECTED) {
 292		spin_unlock_irq(cdev->ccwlock);
 293		wait_event(cdev->private->wait_q, (dev_fsm_final_state(cdev) ||
 294			   cdev->private->state == DEV_STATE_DISCONNECTED));
 295		spin_lock_irq(cdev->ccwlock);
 296	}
 297	do {
 298		ret = ccw_device_offline(cdev);
 299		if (!ret)
 300			break;
 301		CIO_MSG_EVENT(0, "ccw_device_offline returned %d, device "
 302			      "0.%x.%04x\n", ret, cdev->private->dev_id.ssid,
 303			      cdev->private->dev_id.devno);
 304		if (ret != -EBUSY)
 305			goto error;
 306		state = cdev->private->state;
 307		spin_unlock_irq(cdev->ccwlock);
 308		io_subchannel_quiesce(sch);
 309		spin_lock_irq(cdev->ccwlock);
 310		cdev->private->state = state;
 311	} while (ret == -EBUSY);
 312	spin_unlock_irq(cdev->ccwlock);
 313	wait_event(cdev->private->wait_q, (dev_fsm_final_state(cdev) ||
 314		   cdev->private->state == DEV_STATE_DISCONNECTED));
 315	/* Inform the user if set offline failed. */
 316	if (cdev->private->state == DEV_STATE_BOXED) {
 317		pr_warn("%s: The device entered boxed state while being set offline\n",
 318			dev_name(&cdev->dev));
 319	} else if (cdev->private->state == DEV_STATE_NOT_OPER) {
 320		pr_warn("%s: The device stopped operating while being set offline\n",
 321			dev_name(&cdev->dev));
 322	}
 323	/* Give up reference from ccw_device_set_online(). */
 324	put_device(&cdev->dev);
 325	return 0;
 326
 327error:
 328	cdev->private->state = DEV_STATE_OFFLINE;
 329	dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
 330	spin_unlock_irq(cdev->ccwlock);
 331	/* Give up reference from ccw_device_set_online(). */
 332	put_device(&cdev->dev);
 333	return -ENODEV;
 334}
 335
 336/**
 337 * ccw_device_set_online() - enable a ccw device for I/O
 338 * @cdev: target ccw device
 339 *
 340 * This function first enables @cdev and then calls the driver's set_online()
 341 * function for @cdev, if given. If set_online() returns an error, @cdev is
 342 * disabled again.
 343 * Returns:
 344 *   %0 on success and a negative error value on failure.
 345 * Context:
 346 *  enabled, ccw device lock not held
 347 */
 348int ccw_device_set_online(struct ccw_device *cdev)
 349{
 350	int ret;
 351	int ret2;
 352
 353	if (!cdev)
 354		return -ENODEV;
 355	if (cdev->online || !cdev->drv)
 356		return -EINVAL;
 357	/* Hold on to an extra reference while device is online. */
 358	if (!get_device(&cdev->dev))
 359		return -ENODEV;
 360
 361	spin_lock_irq(cdev->ccwlock);
 362	ret = ccw_device_online(cdev);
 363	if (ret) {
 364		spin_unlock_irq(cdev->ccwlock);
 365		CIO_MSG_EVENT(0, "ccw_device_online returned %d, "
 366			      "device 0.%x.%04x\n",
 367			      ret, cdev->private->dev_id.ssid,
 368			      cdev->private->dev_id.devno);
 369		/* Give up online reference since onlining failed. */
 370		put_device(&cdev->dev);
 371		return ret;
 372	}
 373	/* Wait until a final state is reached */
 374	while (!dev_fsm_final_state(cdev)) {
 375		spin_unlock_irq(cdev->ccwlock);
 376		wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev));
 377		spin_lock_irq(cdev->ccwlock);
 378	}
 379	/* Check if online processing was successful */
 380	if ((cdev->private->state != DEV_STATE_ONLINE) &&
 381	    (cdev->private->state != DEV_STATE_W4SENSE)) {
 382		spin_unlock_irq(cdev->ccwlock);
 383		/* Inform the user that set online failed. */
 384		if (cdev->private->state == DEV_STATE_BOXED) {
 385			pr_warn("%s: Setting the device online failed because it is boxed\n",
 386				dev_name(&cdev->dev));
 387		} else if (cdev->private->state == DEV_STATE_NOT_OPER) {
 388			pr_warn("%s: Setting the device online failed because it is not operational\n",
 389				dev_name(&cdev->dev));
 390		}
 391		/* Give up online reference since onlining failed. */
 392		put_device(&cdev->dev);
 393		return -ENODEV;
 394	}
 395	spin_unlock_irq(cdev->ccwlock);
 396	if (cdev->drv->set_online)
 397		ret = cdev->drv->set_online(cdev);
 398	if (ret)
 399		goto rollback;
 400
 401	spin_lock_irq(cdev->ccwlock);
 402	cdev->online = 1;
 403	spin_unlock_irq(cdev->ccwlock);
 404	return 0;
 405
 406rollback:
 407	spin_lock_irq(cdev->ccwlock);
 408	/* Wait until a final state or DISCONNECTED is reached */
 409	while (!dev_fsm_final_state(cdev) &&
 410	       cdev->private->state != DEV_STATE_DISCONNECTED) {
 411		spin_unlock_irq(cdev->ccwlock);
 412		wait_event(cdev->private->wait_q, (dev_fsm_final_state(cdev) ||
 413			   cdev->private->state == DEV_STATE_DISCONNECTED));
 414		spin_lock_irq(cdev->ccwlock);
 415	}
 416	ret2 = ccw_device_offline(cdev);
 417	if (ret2)
 418		goto error;
 419	spin_unlock_irq(cdev->ccwlock);
 420	wait_event(cdev->private->wait_q, (dev_fsm_final_state(cdev) ||
 421		   cdev->private->state == DEV_STATE_DISCONNECTED));
 422	/* Give up online reference since onlining failed. */
 423	put_device(&cdev->dev);
 424	return ret;
 425
 426error:
 427	CIO_MSG_EVENT(0, "rollback ccw_device_offline returned %d, "
 428		      "device 0.%x.%04x\n",
 429		      ret2, cdev->private->dev_id.ssid,
 430		      cdev->private->dev_id.devno);
 431	cdev->private->state = DEV_STATE_OFFLINE;
 432	spin_unlock_irq(cdev->ccwlock);
 433	/* Give up online reference since onlining failed. */
 434	put_device(&cdev->dev);
 435	return ret;
 436}
 437
 438static int online_store_handle_offline(struct ccw_device *cdev)
 439{
 440	if (cdev->private->state == DEV_STATE_DISCONNECTED) {
 441		spin_lock_irq(cdev->ccwlock);
 442		ccw_device_sched_todo(cdev, CDEV_TODO_UNREG_EVAL);
 443		spin_unlock_irq(cdev->ccwlock);
 444		return 0;
 445	}
 446	if (cdev->drv && cdev->drv->set_offline)
 447		return ccw_device_set_offline(cdev);
 448	return -EINVAL;
 449}
 450
 451static int online_store_recog_and_online(struct ccw_device *cdev)
 452{
 453	/* Do device recognition, if needed. */
 454	if (cdev->private->state == DEV_STATE_BOXED) {
 455		spin_lock_irq(cdev->ccwlock);
 456		ccw_device_recognition(cdev);
 457		spin_unlock_irq(cdev->ccwlock);
 458		wait_event(cdev->private->wait_q,
 459			   cdev->private->flags.recog_done);
 460		if (cdev->private->state != DEV_STATE_OFFLINE)
 461			/* recognition failed */
 462			return -EAGAIN;
 463	}
 464	if (cdev->drv && cdev->drv->set_online)
 465		return ccw_device_set_online(cdev);
 466	return -EINVAL;
 467}
 468
 469static int online_store_handle_online(struct ccw_device *cdev, int force)
 470{
 471	int ret;
 472
 473	ret = online_store_recog_and_online(cdev);
 474	if (ret && !force)
 475		return ret;
 476	if (force && cdev->private->state == DEV_STATE_BOXED) {
 477		ret = ccw_device_stlck(cdev);
 478		if (ret)
 479			return ret;
 480		if (cdev->id.cu_type == 0)
 481			cdev->private->state = DEV_STATE_NOT_OPER;
 482		ret = online_store_recog_and_online(cdev);
 483		if (ret)
 484			return ret;
 485	}
 486	return 0;
 487}
 488
 489static ssize_t online_store (struct device *dev, struct device_attribute *attr,
 490			     const char *buf, size_t count)
 491{
 492	struct ccw_device *cdev = to_ccwdev(dev);
 493	int force, ret;
 494	unsigned long i;
 495
 496	/* Prevent conflict between multiple on-/offline processing requests. */
 497	if (atomic_cmpxchg(&cdev->private->onoff, 0, 1) != 0)
 498		return -EAGAIN;
 499	/* Prevent conflict between internal I/Os and on-/offline processing. */
 500	if (!dev_fsm_final_state(cdev) &&
 501	    cdev->private->state != DEV_STATE_DISCONNECTED) {
 502		ret = -EAGAIN;
 503		goto out;
 504	}
 505	/* Prevent conflict between pending work and on-/offline processing.*/
 506	if (work_pending(&cdev->private->todo_work)) {
 507		ret = -EAGAIN;
 508		goto out;
 509	}
 510	if (!strncmp(buf, "force\n", count)) {
 511		force = 1;
 512		i = 1;
 513		ret = 0;
 514	} else {
 515		force = 0;
 516		ret = kstrtoul(buf, 16, &i);
 517	}
 518	if (ret)
 519		goto out;
 520
 521	device_lock(dev);
 522	switch (i) {
 523	case 0:
 524		ret = online_store_handle_offline(cdev);
 525		break;
 526	case 1:
 527		ret = online_store_handle_online(cdev, force);
 528		break;
 529	default:
 530		ret = -EINVAL;
 531	}
 532	device_unlock(dev);
 533
 534out:
 535	atomic_set(&cdev->private->onoff, 0);
 536	return (ret < 0) ? ret : count;
 537}
 538
 539static ssize_t
 540available_show (struct device *dev, struct device_attribute *attr, char *buf)
 541{
 542	struct ccw_device *cdev = to_ccwdev(dev);
 543	struct subchannel *sch;
 544
 545	if (ccw_device_is_orphan(cdev))
 546		return sysfs_emit(buf, "no device\n");
 547	switch (cdev->private->state) {
 548	case DEV_STATE_BOXED:
 549		return sysfs_emit(buf, "boxed\n");
 550	case DEV_STATE_DISCONNECTED:
 551	case DEV_STATE_DISCONNECTED_SENSE_ID:
 552	case DEV_STATE_NOT_OPER:
 553		sch = to_subchannel(dev->parent);
 554		if (!sch->lpm)
 555			return sysfs_emit(buf, "no path\n");
 556		else
 557			return sysfs_emit(buf, "no device\n");
 558	default:
 559		/* All other states considered fine. */
 560		return sysfs_emit(buf, "good\n");
 561	}
 562}
 563
 564static ssize_t
 565initiate_logging(struct device *dev, struct device_attribute *attr,
 566		 const char *buf, size_t count)
 567{
 568	struct subchannel *sch = to_subchannel(dev);
 569	int rc;
 570
 571	rc = chsc_siosl(sch->schid);
 572	if (rc < 0) {
 573		pr_warn("Logging for subchannel 0.%x.%04x failed with errno=%d\n",
 574			sch->schid.ssid, sch->schid.sch_no, rc);
 575		return rc;
 576	}
 577	pr_notice("Logging for subchannel 0.%x.%04x was triggered\n",
 578		  sch->schid.ssid, sch->schid.sch_no);
 579	return count;
 580}
 581
 582static ssize_t vpm_show(struct device *dev, struct device_attribute *attr,
 583			char *buf)
 584{
 585	struct subchannel *sch = to_subchannel(dev);
 586
 587	return sysfs_emit(buf, "%02x\n", sch->vpm);
 588}
 589
 590static DEVICE_ATTR_RO(devtype);
 591static DEVICE_ATTR_RO(cutype);
 592static DEVICE_ATTR_RO(modalias);
 593static DEVICE_ATTR_RW(online);
 594static DEVICE_ATTR(availability, 0444, available_show, NULL);
 595static DEVICE_ATTR(logging, 0200, NULL, initiate_logging);
 596static DEVICE_ATTR_RO(vpm);
 597
 598static struct attribute *io_subchannel_attrs[] = {
 599	&dev_attr_logging.attr,
 600	&dev_attr_vpm.attr,
 601	NULL,
 602};
 603
 604static const struct attribute_group io_subchannel_attr_group = {
 605	.attrs = io_subchannel_attrs,
 606};
 607
 608static struct attribute * ccwdev_attrs[] = {
 609	&dev_attr_devtype.attr,
 610	&dev_attr_cutype.attr,
 611	&dev_attr_modalias.attr,
 612	&dev_attr_online.attr,
 613	&dev_attr_cmb_enable.attr,
 614	&dev_attr_availability.attr,
 615	NULL,
 616};
 617
 618static const struct attribute_group ccwdev_attr_group = {
 619	.attrs = ccwdev_attrs,
 620};
 621
 622static const struct attribute_group *ccwdev_attr_groups[] = {
 623	&ccwdev_attr_group,
 624	NULL,
 625};
 626
 627static int match_dev_id(struct device *dev, const void *data)
 628{
 629	struct ccw_device *cdev = to_ccwdev(dev);
 630	struct ccw_dev_id *dev_id = (void *)data;
 631
 632	return ccw_dev_id_is_equal(&cdev->private->dev_id, dev_id);
 633}
 634
 635/**
 636 * get_ccwdev_by_dev_id() - obtain device from a ccw device id
 637 * @dev_id: id of the device to be searched
 638 *
 639 * This function searches all devices attached to the ccw bus for a device
 640 * matching @dev_id.
 641 * Returns:
 642 *  If a device is found its reference count is increased and returned;
 643 *  else %NULL is returned.
 644 */
 645struct ccw_device *get_ccwdev_by_dev_id(struct ccw_dev_id *dev_id)
 646{
 647	struct device *dev;
 648
 649	dev = bus_find_device(&ccw_bus_type, NULL, dev_id, match_dev_id);
 650
 651	return dev ? to_ccwdev(dev) : NULL;
 652}
 653EXPORT_SYMBOL_GPL(get_ccwdev_by_dev_id);
 654
 655static void ccw_device_do_unbind_bind(struct ccw_device *cdev)
 656{
 657	int ret;
 658
 659	mutex_lock(&cdev->reg_mutex);
 660	if (device_is_registered(&cdev->dev)) {
 661		device_release_driver(&cdev->dev);
 662		ret = device_attach(&cdev->dev);
 663		WARN_ON(ret == -ENODEV);
 664	}
 665	mutex_unlock(&cdev->reg_mutex);
 666}
 667
 668static void
 669ccw_device_release(struct device *dev)
 670{
 671	struct ccw_device *cdev;
 672
 673	cdev = to_ccwdev(dev);
 674	cio_gp_dma_free(cdev->private->dma_pool, cdev->private->dma_area,
 675			sizeof(*cdev->private->dma_area));
 676	cio_gp_dma_destroy(cdev->private->dma_pool, &cdev->dev);
 677	/* Release reference of parent subchannel. */
 678	put_device(cdev->dev.parent);
 679	kfree(cdev->private);
 680	kfree(cdev);
 681}
 682
 683static struct ccw_device * io_subchannel_allocate_dev(struct subchannel *sch)
 684{
 685	struct ccw_device *cdev;
 686	struct gen_pool *dma_pool;
 687	int ret;
 688
 689	cdev  = kzalloc(sizeof(*cdev), GFP_KERNEL);
 690	if (!cdev) {
 691		ret = -ENOMEM;
 692		goto err_cdev;
 693	}
 694	cdev->private = kzalloc(sizeof(struct ccw_device_private),
 695				GFP_KERNEL | GFP_DMA);
 696	if (!cdev->private) {
 697		ret = -ENOMEM;
 698		goto err_priv;
 699	}
 700
 701	cdev->dev.dma_mask = sch->dev.dma_mask;
 702	ret = dma_set_coherent_mask(&cdev->dev, sch->dev.coherent_dma_mask);
 703	if (ret)
 704		goto err_coherent_mask;
 705
 706	dma_pool = cio_gp_dma_create(&cdev->dev, 1);
 707	if (!dma_pool) {
 708		ret = -ENOMEM;
 709		goto err_dma_pool;
 710	}
 711	cdev->private->dma_pool = dma_pool;
 712	cdev->private->dma_area = cio_gp_dma_zalloc(dma_pool, &cdev->dev,
 713					sizeof(*cdev->private->dma_area));
 714	if (!cdev->private->dma_area) {
 715		ret = -ENOMEM;
 716		goto err_dma_area;
 717	}
 718	return cdev;
 719err_dma_area:
 720	cio_gp_dma_destroy(dma_pool, &cdev->dev);
 721err_dma_pool:
 722err_coherent_mask:
 723	kfree(cdev->private);
 724err_priv:
 725	kfree(cdev);
 726err_cdev:
 727	return ERR_PTR(ret);
 728}
 729
 730static void ccw_device_todo(struct work_struct *work);
 731
 732static int io_subchannel_initialize_dev(struct subchannel *sch,
 733					struct ccw_device *cdev)
 734{
 735	struct ccw_device_private *priv = cdev->private;
 736	int ret;
 737
 738	priv->cdev = cdev;
 739	priv->int_class = IRQIO_CIO;
 740	priv->state = DEV_STATE_NOT_OPER;
 741	priv->dev_id.devno = sch->schib.pmcw.dev;
 742	priv->dev_id.ssid = sch->schid.ssid;
 743
 744	INIT_WORK(&priv->todo_work, ccw_device_todo);
 745	INIT_LIST_HEAD(&priv->cmb_list);
 746	init_waitqueue_head(&priv->wait_q);
 747	timer_setup(&priv->timer, ccw_device_timeout, 0);
 748	mutex_init(&cdev->reg_mutex);
 749
 750	atomic_set(&priv->onoff, 0);
 751	cdev->ccwlock = &sch->lock;
 752	cdev->dev.parent = &sch->dev;
 753	cdev->dev.release = ccw_device_release;
 754	cdev->dev.bus = &ccw_bus_type;
 755	cdev->dev.groups = ccwdev_attr_groups;
 756	/* Do first half of device_register. */
 757	device_initialize(&cdev->dev);
 758	ret = dev_set_name(&cdev->dev, "0.%x.%04x", cdev->private->dev_id.ssid,
 759			   cdev->private->dev_id.devno);
 760	if (ret)
 761		goto out_put;
 762	if (!get_device(&sch->dev)) {
 763		ret = -ENODEV;
 764		goto out_put;
 765	}
 766	priv->flags.initialized = 1;
 767	spin_lock_irq(&sch->lock);
 768	sch_set_cdev(sch, cdev);
 769	spin_unlock_irq(&sch->lock);
 770	return 0;
 771
 772out_put:
 773	/* Release reference from device_initialize(). */
 774	put_device(&cdev->dev);
 775	return ret;
 776}
 777
 778static struct ccw_device * io_subchannel_create_ccwdev(struct subchannel *sch)
 779{
 780	struct ccw_device *cdev;
 781	int ret;
 782
 783	cdev = io_subchannel_allocate_dev(sch);
 784	if (!IS_ERR(cdev)) {
 785		ret = io_subchannel_initialize_dev(sch, cdev);
 786		if (ret)
 787			cdev = ERR_PTR(ret);
 788	}
 789	return cdev;
 790}
 791
 792static void io_subchannel_recog(struct ccw_device *, struct subchannel *);
 793
 794static void sch_create_and_recog_new_device(struct subchannel *sch)
 795{
 796	struct ccw_device *cdev;
 797
 798	/* Need to allocate a new ccw device. */
 799	cdev = io_subchannel_create_ccwdev(sch);
 800	if (IS_ERR(cdev)) {
 801		/* OK, we did everything we could... */
 802		css_sch_device_unregister(sch);
 803		return;
 804	}
 805	/* Start recognition for the new ccw device. */
 806	io_subchannel_recog(cdev, sch);
 807}
 808
 809/*
 810 * Register recognized device.
 811 */
 812static void io_subchannel_register(struct ccw_device *cdev)
 813{
 814	struct subchannel *sch;
 815	int ret, adjust_init_count = 1;
 816	unsigned long flags;
 817
 818	sch = to_subchannel(cdev->dev.parent);
 819	/*
 820	 * Check if subchannel is still registered. It may have become
 821	 * unregistered if a machine check hit us after finishing
 822	 * device recognition but before the register work could be
 823	 * queued.
 824	 */
 825	if (!device_is_registered(&sch->dev))
 826		goto out_err;
 827	css_update_ssd_info(sch);
 828	/*
 829	 * io_subchannel_register() will also be called after device
 830	 * recognition has been done for a boxed device (which will already
 831	 * be registered). We need to reprobe since we may now have sense id
 832	 * information.
 833	 */
 834	mutex_lock(&cdev->reg_mutex);
 835	if (device_is_registered(&cdev->dev)) {
 836		if (!cdev->drv) {
 837			ret = device_reprobe(&cdev->dev);
 838			if (ret)
 839				/* We can't do much here. */
 840				CIO_MSG_EVENT(0, "device_reprobe() returned"
 841					      " %d for 0.%x.%04x\n", ret,
 842					      cdev->private->dev_id.ssid,
 843					      cdev->private->dev_id.devno);
 844		}
 845		adjust_init_count = 0;
 846		goto out;
 847	}
 848	/* make it known to the system */
 849	ret = device_add(&cdev->dev);
 850	if (ret) {
 851		CIO_MSG_EVENT(0, "Could not register ccw dev 0.%x.%04x: %d\n",
 852			      cdev->private->dev_id.ssid,
 853			      cdev->private->dev_id.devno, ret);
 854		spin_lock_irqsave(&sch->lock, flags);
 855		sch_set_cdev(sch, NULL);
 856		spin_unlock_irqrestore(&sch->lock, flags);
 857		mutex_unlock(&cdev->reg_mutex);
 858		/* Release initial device reference. */
 859		put_device(&cdev->dev);
 860		goto out_err;
 861	}
 862out:
 863	cdev->private->flags.recog_done = 1;
 864	mutex_unlock(&cdev->reg_mutex);
 865	wake_up(&cdev->private->wait_q);
 866out_err:
 867	if (adjust_init_count && atomic_dec_and_test(&ccw_device_init_count))
 868		wake_up(&ccw_device_init_wq);
 869}
 870
 871/*
 872 * subchannel recognition done. Called from the state machine.
 873 */
 874void
 875io_subchannel_recog_done(struct ccw_device *cdev)
 876{
 877	if (css_init_done == 0) {
 878		cdev->private->flags.recog_done = 1;
 879		return;
 880	}
 881	switch (cdev->private->state) {
 882	case DEV_STATE_BOXED:
 883		/* Device did not respond in time. */
 884	case DEV_STATE_NOT_OPER:
 885		cdev->private->flags.recog_done = 1;
 886		/* Remove device found not operational. */
 887		ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
 888		if (atomic_dec_and_test(&ccw_device_init_count))
 889			wake_up(&ccw_device_init_wq);
 890		break;
 891	case DEV_STATE_OFFLINE:
 892		/*
 893		 * We can't register the device in interrupt context so
 894		 * we schedule a work item.
 895		 */
 896		ccw_device_sched_todo(cdev, CDEV_TODO_REGISTER);
 897		break;
 898	}
 899}
 900
 901static void io_subchannel_recog(struct ccw_device *cdev, struct subchannel *sch)
 902{
 903	/* Increase counter of devices currently in recognition. */
 904	atomic_inc(&ccw_device_init_count);
 905
 906	/* Start async. device sensing. */
 907	spin_lock_irq(&sch->lock);
 908	ccw_device_recognition(cdev);
 909	spin_unlock_irq(&sch->lock);
 910}
 911
 912static int ccw_device_move_to_sch(struct ccw_device *cdev,
 913				  struct subchannel *sch)
 914{
 915	struct subchannel *old_sch;
 916	int rc, old_enabled = 0;
 917
 918	old_sch = to_subchannel(cdev->dev.parent);
 919	/* Obtain child reference for new parent. */
 920	if (!get_device(&sch->dev))
 921		return -ENODEV;
 922
 923	if (!sch_is_pseudo_sch(old_sch)) {
 924		spin_lock_irq(&old_sch->lock);
 925		old_enabled = old_sch->schib.pmcw.ena;
 926		rc = 0;
 927		if (old_enabled)
 928			rc = cio_disable_subchannel(old_sch);
 929		spin_unlock_irq(&old_sch->lock);
 930		if (rc == -EBUSY) {
 931			/* Release child reference for new parent. */
 932			put_device(&sch->dev);
 933			return rc;
 934		}
 935	}
 936
 937	mutex_lock(&sch->reg_mutex);
 938	rc = device_move(&cdev->dev, &sch->dev, DPM_ORDER_PARENT_BEFORE_DEV);
 939	mutex_unlock(&sch->reg_mutex);
 940	if (rc) {
 941		CIO_MSG_EVENT(0, "device_move(0.%x.%04x,0.%x.%04x)=%d\n",
 942			      cdev->private->dev_id.ssid,
 943			      cdev->private->dev_id.devno, sch->schid.ssid,
 944			      sch->schib.pmcw.dev, rc);
 945		if (old_enabled) {
 946			/* Try to re-enable the old subchannel. */
 947			spin_lock_irq(&old_sch->lock);
 948			cio_enable_subchannel(old_sch, (u32)virt_to_phys(old_sch));
 949			spin_unlock_irq(&old_sch->lock);
 950		}
 951		/* Release child reference for new parent. */
 952		put_device(&sch->dev);
 953		return rc;
 954	}
 955	/* Clean up old subchannel. */
 956	if (!sch_is_pseudo_sch(old_sch)) {
 957		spin_lock_irq(&old_sch->lock);
 958		sch_set_cdev(old_sch, NULL);
 959		spin_unlock_irq(&old_sch->lock);
 960		css_schedule_eval(old_sch->schid);
 961	}
 962	/* Release child reference for old parent. */
 963	put_device(&old_sch->dev);
 964	/* Initialize new subchannel. */
 965	spin_lock_irq(&sch->lock);
 966	cdev->ccwlock = &sch->lock;
 967	if (!sch_is_pseudo_sch(sch))
 968		sch_set_cdev(sch, cdev);
 969	spin_unlock_irq(&sch->lock);
 970	if (!sch_is_pseudo_sch(sch))
 971		css_update_ssd_info(sch);
 972	return 0;
 973}
 974
 975static int ccw_device_move_to_orph(struct ccw_device *cdev)
 976{
 977	struct subchannel *sch = to_subchannel(cdev->dev.parent);
 978	struct channel_subsystem *css = to_css(sch->dev.parent);
 979
 980	return ccw_device_move_to_sch(cdev, css->pseudo_subchannel);
 981}
 982
 983static void io_subchannel_irq(struct subchannel *sch)
 984{
 985	struct ccw_device *cdev;
 986
 987	cdev = sch_get_cdev(sch);
 988
 989	CIO_TRACE_EVENT(6, "IRQ");
 990	CIO_TRACE_EVENT(6, dev_name(&sch->dev));
 991	if (cdev)
 992		dev_fsm_event(cdev, DEV_EVENT_INTERRUPT);
 993	else
 994		inc_irq_stat(IRQIO_CIO);
 995}
 996
 997void io_subchannel_init_config(struct subchannel *sch)
 998{
 999	memset(&sch->config, 0, sizeof(sch->config));
1000	sch->config.csense = 1;
1001}
1002
1003static void io_subchannel_init_fields(struct subchannel *sch)
1004{
1005	if (cio_is_console(sch->schid))
1006		sch->opm = 0xff;
1007	else
1008		sch->opm = chp_get_sch_opm(sch);
1009	sch->lpm = sch->schib.pmcw.pam & sch->opm;
1010	sch->isc = cio_is_console(sch->schid) ? CONSOLE_ISC : IO_SCH_ISC;
1011
1012	CIO_MSG_EVENT(6, "Detected device %04x on subchannel 0.%x.%04X"
1013		      " - PIM = %02X, PAM = %02X, POM = %02X\n",
1014		      sch->schib.pmcw.dev, sch->schid.ssid,
1015		      sch->schid.sch_no, sch->schib.pmcw.pim,
1016		      sch->schib.pmcw.pam, sch->schib.pmcw.pom);
1017
1018	io_subchannel_init_config(sch);
1019}
1020
1021/*
1022 * Note: We always return 0 so that we bind to the device even on error.
1023 * This is needed so that our remove function is called on unregister.
1024 */
1025static int io_subchannel_probe(struct subchannel *sch)
1026{
1027	struct io_subchannel_private *io_priv;
1028	struct ccw_device *cdev;
1029	int rc;
1030
1031	if (cio_is_console(sch->schid)) {
1032		rc = sysfs_create_group(&sch->dev.kobj,
1033					&io_subchannel_attr_group);
1034		if (rc)
1035			CIO_MSG_EVENT(0, "Failed to create io subchannel "
1036				      "attributes for subchannel "
1037				      "0.%x.%04x (rc=%d)\n",
1038				      sch->schid.ssid, sch->schid.sch_no, rc);
1039		/*
1040		* The console subchannel already has an associated ccw_device.
1041		* Register it and exit.
1042		*/
1043		cdev = sch_get_cdev(sch);
1044		rc = device_add(&cdev->dev);
1045		if (rc) {
1046			/* Release online reference. */
1047			put_device(&cdev->dev);
1048			goto out_schedule;
1049		}
1050		if (atomic_dec_and_test(&ccw_device_init_count))
1051			wake_up(&ccw_device_init_wq);
1052		return 0;
1053	}
1054	io_subchannel_init_fields(sch);
1055	rc = cio_commit_config(sch);
1056	if (rc)
1057		goto out_schedule;
1058	rc = sysfs_create_group(&sch->dev.kobj,
1059				&io_subchannel_attr_group);
1060	if (rc)
1061		goto out_schedule;
1062	/* Allocate I/O subchannel private data. */
1063	io_priv = kzalloc(sizeof(*io_priv), GFP_KERNEL | GFP_DMA);
1064	if (!io_priv)
1065		goto out_schedule;
1066
1067	io_priv->dma_area = dma_alloc_coherent(&sch->dev,
1068				sizeof(*io_priv->dma_area),
1069				&io_priv->dma_area_dma, GFP_KERNEL);
1070	if (!io_priv->dma_area) {
1071		kfree(io_priv);
1072		goto out_schedule;
1073	}
1074
1075	set_io_private(sch, io_priv);
1076	css_schedule_eval(sch->schid);
1077	return 0;
1078
1079out_schedule:
1080	spin_lock_irq(&sch->lock);
1081	css_sched_sch_todo(sch, SCH_TODO_UNREG);
1082	spin_unlock_irq(&sch->lock);
1083	return 0;
1084}
1085
1086static void io_subchannel_remove(struct subchannel *sch)
1087{
1088	struct io_subchannel_private *io_priv = to_io_private(sch);
1089	struct ccw_device *cdev;
1090
1091	cdev = sch_get_cdev(sch);
1092	if (!cdev)
1093		goto out_free;
1094
1095	ccw_device_unregister(cdev);
1096	spin_lock_irq(&sch->lock);
1097	sch_set_cdev(sch, NULL);
1098	set_io_private(sch, NULL);
1099	spin_unlock_irq(&sch->lock);
1100out_free:
1101	dma_free_coherent(&sch->dev, sizeof(*io_priv->dma_area),
1102			  io_priv->dma_area, io_priv->dma_area_dma);
1103	kfree(io_priv);
1104	sysfs_remove_group(&sch->dev.kobj, &io_subchannel_attr_group);
1105}
1106
1107static void io_subchannel_verify(struct subchannel *sch)
1108{
1109	struct ccw_device *cdev;
1110
1111	cdev = sch_get_cdev(sch);
1112	if (cdev)
1113		dev_fsm_event(cdev, DEV_EVENT_VERIFY);
1114	else
1115		css_schedule_eval(sch->schid);
1116}
1117
1118static void io_subchannel_terminate_path(struct subchannel *sch, u8 mask)
1119{
1120	struct ccw_device *cdev;
1121
1122	cdev = sch_get_cdev(sch);
1123	if (!cdev)
1124		return;
1125	if (cio_update_schib(sch))
1126		goto err;
1127	/* Check for I/O on path. */
1128	if (scsw_actl(&sch->schib.scsw) == 0 || sch->schib.pmcw.lpum != mask)
1129		goto out;
1130	if (cdev->private->state == DEV_STATE_ONLINE) {
1131		ccw_device_kill_io(cdev);
1132		goto out;
1133	}
1134	if (cio_clear(sch))
1135		goto err;
1136out:
1137	/* Trigger path verification. */
1138	dev_fsm_event(cdev, DEV_EVENT_VERIFY);
1139	return;
1140
1141err:
1142	dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
1143}
1144
1145static int io_subchannel_chp_event(struct subchannel *sch,
1146				   struct chp_link *link, int event)
1147{
1148	struct ccw_device *cdev = sch_get_cdev(sch);
1149	int mask, chpid, valid_bit;
1150	int path_event[8];
1151
1152	mask = chp_ssd_get_mask(&sch->ssd_info, link);
1153	if (!mask)
1154		return 0;
1155	switch (event) {
1156	case CHP_VARY_OFF:
1157		sch->opm &= ~mask;
1158		sch->lpm &= ~mask;
1159		if (cdev)
1160			cdev->private->path_gone_mask |= mask;
1161		io_subchannel_terminate_path(sch, mask);
1162		break;
1163	case CHP_VARY_ON:
1164		sch->opm |= mask;
1165		sch->lpm |= mask;
1166		if (cdev)
1167			cdev->private->path_new_mask |= mask;
1168		io_subchannel_verify(sch);
1169		break;
1170	case CHP_OFFLINE:
1171		if (cio_update_schib(sch))
1172			return -ENODEV;
1173		if (cdev)
1174			cdev->private->path_gone_mask |= mask;
1175		io_subchannel_terminate_path(sch, mask);
1176		break;
1177	case CHP_ONLINE:
1178		if (cio_update_schib(sch))
1179			return -ENODEV;
1180		sch->lpm |= mask & sch->opm;
1181		if (cdev)
1182			cdev->private->path_new_mask |= mask;
1183		io_subchannel_verify(sch);
1184		break;
1185	case CHP_FCES_EVENT:
1186		/* Forward Endpoint Security event */
1187		for (chpid = 0, valid_bit = 0x80; chpid < 8; chpid++,
1188				valid_bit >>= 1) {
1189			if (mask & valid_bit)
1190				path_event[chpid] = PE_PATH_FCES_EVENT;
1191			else
1192				path_event[chpid] = PE_NONE;
1193		}
1194		if (cdev && cdev->drv && cdev->drv->path_event)
1195			cdev->drv->path_event(cdev, path_event);
1196		break;
1197	}
1198	return 0;
1199}
1200
1201static void io_subchannel_quiesce(struct subchannel *sch)
1202{
1203	struct ccw_device *cdev;
1204	int ret;
1205
1206	spin_lock_irq(&sch->lock);
1207	cdev = sch_get_cdev(sch);
1208	if (cio_is_console(sch->schid))
1209		goto out_unlock;
1210	if (!sch->schib.pmcw.ena)
1211		goto out_unlock;
1212	ret = cio_disable_subchannel(sch);
1213	if (ret != -EBUSY)
1214		goto out_unlock;
1215	if (cdev->handler)
1216		cdev->handler(cdev, cdev->private->intparm, ERR_PTR(-EIO));
1217	while (ret == -EBUSY) {
1218		cdev->private->state = DEV_STATE_QUIESCE;
1219		cdev->private->iretry = 255;
1220		ret = ccw_device_cancel_halt_clear(cdev);
1221		if (ret == -EBUSY) {
1222			ccw_device_set_timeout(cdev, HZ/10);
1223			spin_unlock_irq(&sch->lock);
1224			wait_event(cdev->private->wait_q,
1225				   cdev->private->state != DEV_STATE_QUIESCE);
1226			spin_lock_irq(&sch->lock);
1227		}
1228		ret = cio_disable_subchannel(sch);
1229	}
1230out_unlock:
1231	spin_unlock_irq(&sch->lock);
1232}
1233
1234static void io_subchannel_shutdown(struct subchannel *sch)
1235{
1236	io_subchannel_quiesce(sch);
1237}
1238
1239static int device_is_disconnected(struct ccw_device *cdev)
1240{
1241	if (!cdev)
1242		return 0;
1243	return (cdev->private->state == DEV_STATE_DISCONNECTED ||
1244		cdev->private->state == DEV_STATE_DISCONNECTED_SENSE_ID);
1245}
1246
1247static int recovery_check(struct device *dev, void *data)
1248{
1249	struct ccw_device *cdev = to_ccwdev(dev);
1250	struct subchannel *sch;
1251	int *redo = data;
1252
1253	spin_lock_irq(cdev->ccwlock);
1254	switch (cdev->private->state) {
1255	case DEV_STATE_ONLINE:
1256		sch = to_subchannel(cdev->dev.parent);
1257		if ((sch->schib.pmcw.pam & sch->opm) == sch->vpm)
1258			break;
1259		fallthrough;
1260	case DEV_STATE_DISCONNECTED:
1261		CIO_MSG_EVENT(3, "recovery: trigger 0.%x.%04x\n",
1262			      cdev->private->dev_id.ssid,
1263			      cdev->private->dev_id.devno);
1264		dev_fsm_event(cdev, DEV_EVENT_VERIFY);
1265		*redo = 1;
1266		break;
1267	case DEV_STATE_DISCONNECTED_SENSE_ID:
1268		*redo = 1;
1269		break;
1270	}
1271	spin_unlock_irq(cdev->ccwlock);
1272
1273	return 0;
1274}
1275
1276static void recovery_work_func(struct work_struct *unused)
1277{
1278	int redo = 0;
1279
1280	bus_for_each_dev(&ccw_bus_type, NULL, &redo, recovery_check);
1281	if (redo) {
1282		spin_lock_irq(&recovery_lock);
1283		if (!timer_pending(&recovery_timer)) {
1284			if (recovery_phase < ARRAY_SIZE(recovery_delay) - 1)
1285				recovery_phase++;
1286			mod_timer(&recovery_timer, jiffies +
1287				  recovery_delay[recovery_phase] * HZ);
1288		}
1289		spin_unlock_irq(&recovery_lock);
1290	} else
1291		CIO_MSG_EVENT(3, "recovery: end\n");
1292}
1293
1294static DECLARE_WORK(recovery_work, recovery_work_func);
1295
1296static void recovery_func(struct timer_list *unused)
1297{
1298	/*
1299	 * We can't do our recovery in softirq context and it's not
1300	 * performance critical, so we schedule it.
1301	 */
1302	schedule_work(&recovery_work);
1303}
1304
1305void ccw_device_schedule_recovery(void)
1306{
1307	unsigned long flags;
1308
1309	CIO_MSG_EVENT(3, "recovery: schedule\n");
1310	spin_lock_irqsave(&recovery_lock, flags);
1311	if (!timer_pending(&recovery_timer) || (recovery_phase != 0)) {
1312		recovery_phase = 0;
1313		mod_timer(&recovery_timer, jiffies + recovery_delay[0] * HZ);
1314	}
1315	spin_unlock_irqrestore(&recovery_lock, flags);
1316}
1317
1318static int purge_fn(struct subchannel *sch, void *data)
1319{
1320	struct ccw_device *cdev;
1321
1322	spin_lock_irq(&sch->lock);
1323	if (sch->st != SUBCHANNEL_TYPE_IO || !sch->schib.pmcw.dnv)
1324		goto unlock;
1325
1326	if (!is_blacklisted(sch->schid.ssid, sch->schib.pmcw.dev))
1327		goto unlock;
1328
1329	cdev = sch_get_cdev(sch);
1330	if (cdev) {
1331		if (cdev->private->state != DEV_STATE_OFFLINE)
1332			goto unlock;
1333
1334		if (atomic_cmpxchg(&cdev->private->onoff, 0, 1) != 0)
1335			goto unlock;
1336		ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
1337		atomic_set(&cdev->private->onoff, 0);
1338	}
1339
1340	css_sched_sch_todo(sch, SCH_TODO_UNREG);
1341	CIO_MSG_EVENT(3, "ccw: purging 0.%x.%04x%s\n", sch->schid.ssid,
1342		      sch->schib.pmcw.dev, cdev ? "" : " (no cdev)");
1343
1344unlock:
1345	spin_unlock_irq(&sch->lock);
1346	/* Abort loop in case of pending signal. */
1347	if (signal_pending(current))
1348		return -EINTR;
1349
1350	return 0;
1351}
1352
1353/**
1354 * ccw_purge_blacklisted - purge unused, blacklisted devices
1355 *
1356 * Unregister all ccw devices that are offline and on the blacklist.
1357 */
1358int ccw_purge_blacklisted(void)
1359{
1360	CIO_MSG_EVENT(2, "ccw: purging blacklisted devices\n");
1361	for_each_subchannel_staged(purge_fn, NULL, NULL);
1362	return 0;
1363}
1364
1365void ccw_device_set_disconnected(struct ccw_device *cdev)
1366{
1367	if (!cdev)
1368		return;
1369	ccw_device_set_timeout(cdev, 0);
1370	cdev->private->flags.fake_irb = 0;
1371	cdev->private->state = DEV_STATE_DISCONNECTED;
1372	if (cdev->online)
1373		ccw_device_schedule_recovery();
1374}
1375
1376void ccw_device_set_notoper(struct ccw_device *cdev)
1377{
1378	struct subchannel *sch = to_subchannel(cdev->dev.parent);
1379
1380	CIO_TRACE_EVENT(2, "notoper");
1381	CIO_TRACE_EVENT(2, dev_name(&sch->dev));
1382	ccw_device_set_timeout(cdev, 0);
1383	cio_disable_subchannel(sch);
1384	cdev->private->state = DEV_STATE_NOT_OPER;
1385}
1386
1387enum io_sch_action {
1388	IO_SCH_UNREG,
1389	IO_SCH_ORPH_UNREG,
1390	IO_SCH_UNREG_CDEV,
1391	IO_SCH_ATTACH,
1392	IO_SCH_UNREG_ATTACH,
1393	IO_SCH_ORPH_ATTACH,
1394	IO_SCH_REPROBE,
1395	IO_SCH_VERIFY,
1396	IO_SCH_DISC,
1397	IO_SCH_NOP,
1398	IO_SCH_ORPH_CDEV,
1399};
1400
1401static enum io_sch_action sch_get_action(struct subchannel *sch)
1402{
1403	struct ccw_device *cdev;
1404	int rc;
1405
1406	cdev = sch_get_cdev(sch);
1407	rc = cio_update_schib(sch);
1408
1409	if (rc == -ENODEV) {
1410		/* Not operational. */
1411		if (!cdev)
1412			return IO_SCH_UNREG;
1413		if (ccw_device_notify(cdev, CIO_GONE) != NOTIFY_OK)
1414			return IO_SCH_UNREG;
1415		return IO_SCH_ORPH_UNREG;
1416	}
1417
1418	/* Avoid unregistering subchannels without working device. */
1419	if (rc == -EACCES) {
1420		if (!cdev)
1421			return IO_SCH_NOP;
1422		if (ccw_device_notify(cdev, CIO_GONE) != NOTIFY_OK)
1423			return IO_SCH_UNREG_CDEV;
1424		return IO_SCH_ORPH_CDEV;
1425	}
1426
1427	/* Operational. */
1428	if (!cdev)
1429		return IO_SCH_ATTACH;
1430	if (sch->schib.pmcw.dev != cdev->private->dev_id.devno) {
1431		if (ccw_device_notify(cdev, CIO_GONE) != NOTIFY_OK)
1432			return IO_SCH_UNREG_ATTACH;
1433		return IO_SCH_ORPH_ATTACH;
1434	}
1435	if ((sch->schib.pmcw.pam & sch->opm) == 0) {
1436		if (ccw_device_notify(cdev, CIO_NO_PATH) != NOTIFY_OK)
1437			return IO_SCH_UNREG_CDEV;
1438		return IO_SCH_DISC;
1439	}
1440	if (device_is_disconnected(cdev))
1441		return IO_SCH_REPROBE;
1442	if (cdev->online)
1443		return IO_SCH_VERIFY;
1444	if (cdev->private->state == DEV_STATE_NOT_OPER)
1445		return IO_SCH_UNREG_ATTACH;
1446	return IO_SCH_NOP;
1447}
1448
1449/**
1450 * io_subchannel_sch_event - process subchannel event
1451 * @sch: subchannel
1452 * @process: non-zero if function is called in process context
1453 *
1454 * An unspecified event occurred for this subchannel. Adjust data according
1455 * to the current operational state of the subchannel and device. Return
1456 * zero when the event has been handled sufficiently or -EAGAIN when this
1457 * function should be called again in process context.
1458 */
1459static int io_subchannel_sch_event(struct subchannel *sch, int process)
1460{
1461	unsigned long flags;
1462	struct ccw_device *cdev;
1463	struct ccw_dev_id dev_id;
1464	enum io_sch_action action;
1465	int rc = -EAGAIN;
1466
1467	spin_lock_irqsave(&sch->lock, flags);
1468	if (!device_is_registered(&sch->dev))
1469		goto out_unlock;
1470	if (work_pending(&sch->todo_work))
1471		goto out_unlock;
1472	cdev = sch_get_cdev(sch);
1473	if (cdev && work_pending(&cdev->private->todo_work))
1474		goto out_unlock;
1475	action = sch_get_action(sch);
1476	CIO_MSG_EVENT(2, "event: sch 0.%x.%04x, process=%d, action=%d\n",
1477		      sch->schid.ssid, sch->schid.sch_no, process,
1478		      action);
1479	/* Perform immediate actions while holding the lock. */
1480	switch (action) {
1481	case IO_SCH_REPROBE:
1482		/* Trigger device recognition. */
1483		ccw_device_trigger_reprobe(cdev);
1484		rc = 0;
1485		goto out_unlock;
1486	case IO_SCH_VERIFY:
1487		/* Trigger path verification. */
1488		io_subchannel_verify(sch);
1489		rc = 0;
1490		goto out_unlock;
1491	case IO_SCH_DISC:
1492		ccw_device_set_disconnected(cdev);
1493		rc = 0;
1494		goto out_unlock;
1495	case IO_SCH_ORPH_UNREG:
1496	case IO_SCH_ORPH_CDEV:
1497	case IO_SCH_ORPH_ATTACH:
1498		ccw_device_set_disconnected(cdev);
1499		break;
1500	case IO_SCH_UNREG_CDEV:
1501	case IO_SCH_UNREG_ATTACH:
1502	case IO_SCH_UNREG:
1503		if (!cdev)
1504			break;
1505		if (cdev->private->state == DEV_STATE_SENSE_ID) {
1506			/*
1507			 * Note: delayed work triggered by this event
1508			 * and repeated calls to sch_event are synchronized
1509			 * by the above check for work_pending(cdev).
1510			 */
1511			dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
1512		} else
1513			ccw_device_set_notoper(cdev);
1514		break;
1515	case IO_SCH_NOP:
1516		rc = 0;
1517		goto out_unlock;
1518	default:
1519		break;
1520	}
1521	spin_unlock_irqrestore(&sch->lock, flags);
1522	/* All other actions require process context. */
1523	if (!process)
1524		goto out;
1525	/* Handle attached ccw device. */
1526	switch (action) {
1527	case IO_SCH_ORPH_UNREG:
1528	case IO_SCH_ORPH_CDEV:
1529	case IO_SCH_ORPH_ATTACH:
1530		/* Move ccw device to orphanage. */
1531		rc = ccw_device_move_to_orph(cdev);
1532		if (rc)
1533			goto out;
1534		break;
1535	case IO_SCH_UNREG_CDEV:
1536	case IO_SCH_UNREG_ATTACH:
1537		spin_lock_irqsave(&sch->lock, flags);
1538		sch_set_cdev(sch, NULL);
1539		spin_unlock_irqrestore(&sch->lock, flags);
1540		/* Unregister ccw device. */
1541		ccw_device_unregister(cdev);
1542		break;
1543	default:
1544		break;
1545	}
1546	/* Handle subchannel. */
1547	switch (action) {
1548	case IO_SCH_ORPH_UNREG:
1549	case IO_SCH_UNREG:
1550		css_sch_device_unregister(sch);
1551		break;
1552	case IO_SCH_ORPH_ATTACH:
1553	case IO_SCH_UNREG_ATTACH:
1554	case IO_SCH_ATTACH:
1555		dev_id.ssid = sch->schid.ssid;
1556		dev_id.devno = sch->schib.pmcw.dev;
1557		cdev = get_ccwdev_by_dev_id(&dev_id);
1558		if (!cdev) {
1559			sch_create_and_recog_new_device(sch);
1560			break;
1561		}
1562		rc = ccw_device_move_to_sch(cdev, sch);
1563		if (rc) {
1564			/* Release reference from get_ccwdev_by_dev_id() */
1565			put_device(&cdev->dev);
1566			goto out;
1567		}
1568		spin_lock_irqsave(&sch->lock, flags);
1569		ccw_device_trigger_reprobe(cdev);
1570		spin_unlock_irqrestore(&sch->lock, flags);
1571		/* Release reference from get_ccwdev_by_dev_id() */
1572		put_device(&cdev->dev);
1573		break;
1574	default:
1575		break;
1576	}
1577	return 0;
1578
1579out_unlock:
1580	spin_unlock_irqrestore(&sch->lock, flags);
1581out:
1582	return rc;
1583}
1584
1585static void ccw_device_set_int_class(struct ccw_device *cdev)
1586{
1587	struct ccw_driver *cdrv = cdev->drv;
1588
1589	/* Note: we interpret class 0 in this context as an uninitialized
1590	 * field since it translates to a non-I/O interrupt class. */
1591	if (cdrv->int_class != 0)
1592		cdev->private->int_class = cdrv->int_class;
1593	else
1594		cdev->private->int_class = IRQIO_CIO;
1595}
1596
1597#ifdef CONFIG_CCW_CONSOLE
1598int __init ccw_device_enable_console(struct ccw_device *cdev)
1599{
1600	struct subchannel *sch = to_subchannel(cdev->dev.parent);
1601	int rc;
1602
1603	if (!cdev->drv || !cdev->handler)
1604		return -EINVAL;
1605
1606	io_subchannel_init_fields(sch);
1607	rc = cio_commit_config(sch);
1608	if (rc)
1609		return rc;
1610	sch->driver = &io_subchannel_driver;
1611	io_subchannel_recog(cdev, sch);
1612	/* Now wait for the async. recognition to come to an end. */
1613	spin_lock_irq(cdev->ccwlock);
1614	while (!dev_fsm_final_state(cdev))
1615		ccw_device_wait_idle(cdev);
1616
1617	/* Hold on to an extra reference while device is online. */
1618	get_device(&cdev->dev);
1619	rc = ccw_device_online(cdev);
1620	if (rc)
1621		goto out_unlock;
1622
1623	while (!dev_fsm_final_state(cdev))
1624		ccw_device_wait_idle(cdev);
1625
1626	if (cdev->private->state == DEV_STATE_ONLINE)
1627		cdev->online = 1;
1628	else
1629		rc = -EIO;
1630out_unlock:
1631	spin_unlock_irq(cdev->ccwlock);
1632	if (rc) /* Give up online reference since onlining failed. */
1633		put_device(&cdev->dev);
1634	return rc;
1635}
1636
1637struct ccw_device * __init ccw_device_create_console(struct ccw_driver *drv)
1638{
1639	struct io_subchannel_private *io_priv;
1640	struct ccw_device *cdev;
1641	struct subchannel *sch;
1642
1643	sch = cio_probe_console();
1644	if (IS_ERR(sch))
1645		return ERR_CAST(sch);
1646
1647	io_priv = kzalloc(sizeof(*io_priv), GFP_KERNEL | GFP_DMA);
1648	if (!io_priv)
1649		goto err_priv;
1650	io_priv->dma_area = dma_alloc_coherent(&sch->dev,
1651				sizeof(*io_priv->dma_area),
1652				&io_priv->dma_area_dma, GFP_KERNEL);
1653	if (!io_priv->dma_area)
1654		goto err_dma_area;
1655	set_io_private(sch, io_priv);
1656	cdev = io_subchannel_create_ccwdev(sch);
1657	if (IS_ERR(cdev)) {
1658		dma_free_coherent(&sch->dev, sizeof(*io_priv->dma_area),
1659				  io_priv->dma_area, io_priv->dma_area_dma);
1660		set_io_private(sch, NULL);
1661		put_device(&sch->dev);
1662		kfree(io_priv);
1663		return cdev;
1664	}
1665	cdev->drv = drv;
1666	ccw_device_set_int_class(cdev);
1667	return cdev;
1668
1669err_dma_area:
1670	kfree(io_priv);
1671err_priv:
1672	put_device(&sch->dev);
1673	return ERR_PTR(-ENOMEM);
1674}
1675
1676void __init ccw_device_destroy_console(struct ccw_device *cdev)
1677{
1678	struct subchannel *sch = to_subchannel(cdev->dev.parent);
1679	struct io_subchannel_private *io_priv = to_io_private(sch);
1680
1681	set_io_private(sch, NULL);
1682	dma_free_coherent(&sch->dev, sizeof(*io_priv->dma_area),
1683			  io_priv->dma_area, io_priv->dma_area_dma);
1684	put_device(&sch->dev);
1685	put_device(&cdev->dev);
1686	kfree(io_priv);
1687}
1688
1689/**
1690 * ccw_device_wait_idle() - busy wait for device to become idle
1691 * @cdev: ccw device
1692 *
1693 * Poll until activity control is zero, that is, no function or data
1694 * transfer is pending/active.
1695 * Called with device lock being held.
1696 */
1697void ccw_device_wait_idle(struct ccw_device *cdev)
1698{
1699	struct subchannel *sch = to_subchannel(cdev->dev.parent);
1700
1701	while (1) {
1702		cio_tsch(sch);
1703		if (sch->schib.scsw.cmd.actl == 0)
1704			break;
1705		udelay(100);
1706	}
1707}
1708#endif
1709
1710/**
1711 * get_ccwdev_by_busid() - obtain device from a bus id
1712 * @cdrv: driver the device is owned by
1713 * @bus_id: bus id of the device to be searched
1714 *
1715 * This function searches all devices owned by @cdrv for a device with a bus
1716 * id matching @bus_id.
1717 * Returns:
1718 *  If a match is found, its reference count of the found device is increased
1719 *  and it is returned; else %NULL is returned.
1720 */
1721struct ccw_device *get_ccwdev_by_busid(struct ccw_driver *cdrv,
1722				       const char *bus_id)
1723{
1724	struct device *dev;
1725
1726	dev = driver_find_device_by_name(&cdrv->driver, bus_id);
1727
1728	return dev ? to_ccwdev(dev) : NULL;
1729}
1730
1731/************************** device driver handling ************************/
1732
1733/* This is the implementation of the ccw_driver class. The probe, remove
1734 * and release methods are initially very similar to the device_driver
1735 * implementations, with the difference that they have ccw_device
1736 * arguments.
1737 *
1738 * A ccw driver also contains the information that is needed for
1739 * device matching.
1740 */
1741static int
1742ccw_device_probe (struct device *dev)
1743{
1744	struct ccw_device *cdev = to_ccwdev(dev);
1745	struct ccw_driver *cdrv = to_ccwdrv(dev->driver);
1746	int ret;
1747
1748	cdev->drv = cdrv; /* to let the driver call _set_online */
1749	ccw_device_set_int_class(cdev);
1750	ret = cdrv->probe ? cdrv->probe(cdev) : -ENODEV;
1751	if (ret) {
1752		cdev->drv = NULL;
1753		cdev->private->int_class = IRQIO_CIO;
1754		return ret;
1755	}
1756
1757	return 0;
1758}
1759
1760static void ccw_device_remove(struct device *dev)
1761{
1762	struct ccw_device *cdev = to_ccwdev(dev);
1763	struct ccw_driver *cdrv = cdev->drv;
1764	struct subchannel *sch;
1765	int ret;
1766
1767	if (cdrv->remove)
1768		cdrv->remove(cdev);
1769
1770	spin_lock_irq(cdev->ccwlock);
1771	if (cdev->online) {
1772		cdev->online = 0;
1773		ret = ccw_device_offline(cdev);
1774		spin_unlock_irq(cdev->ccwlock);
1775		if (ret == 0)
1776			wait_event(cdev->private->wait_q,
1777				   dev_fsm_final_state(cdev));
1778		else
1779			CIO_MSG_EVENT(0, "ccw_device_offline returned %d, "
1780				      "device 0.%x.%04x\n",
1781				      ret, cdev->private->dev_id.ssid,
1782				      cdev->private->dev_id.devno);
1783		/* Give up reference obtained in ccw_device_set_online(). */
1784		put_device(&cdev->dev);
1785		spin_lock_irq(cdev->ccwlock);
1786	}
1787	ccw_device_set_timeout(cdev, 0);
1788	cdev->drv = NULL;
1789	cdev->private->int_class = IRQIO_CIO;
1790	sch = to_subchannel(cdev->dev.parent);
1791	spin_unlock_irq(cdev->ccwlock);
1792	io_subchannel_quiesce(sch);
1793	__disable_cmf(cdev);
1794}
1795
1796static void ccw_device_shutdown(struct device *dev)
1797{
1798	struct ccw_device *cdev;
1799
1800	cdev = to_ccwdev(dev);
1801	if (cdev->drv && cdev->drv->shutdown)
1802		cdev->drv->shutdown(cdev);
1803	__disable_cmf(cdev);
1804}
1805
1806static const struct bus_type ccw_bus_type = {
1807	.name   = "ccw",
1808	.match  = ccw_bus_match,
1809	.uevent = ccw_uevent,
1810	.probe  = ccw_device_probe,
1811	.remove = ccw_device_remove,
1812	.shutdown = ccw_device_shutdown,
1813};
1814
1815/**
1816 * ccw_driver_register() - register a ccw driver
1817 * @cdriver: driver to be registered
1818 *
1819 * This function is mainly a wrapper around driver_register().
1820 * Returns:
1821 *   %0 on success and a negative error value on failure.
1822 */
1823int ccw_driver_register(struct ccw_driver *cdriver)
1824{
1825	struct device_driver *drv = &cdriver->driver;
1826
1827	drv->bus = &ccw_bus_type;
1828
1829	return driver_register(drv);
1830}
1831
1832/**
1833 * ccw_driver_unregister() - deregister a ccw driver
1834 * @cdriver: driver to be deregistered
1835 *
1836 * This function is mainly a wrapper around driver_unregister().
1837 */
1838void ccw_driver_unregister(struct ccw_driver *cdriver)
1839{
1840	driver_unregister(&cdriver->driver);
1841}
1842
1843static void ccw_device_todo(struct work_struct *work)
1844{
1845	struct ccw_device_private *priv;
1846	struct ccw_device *cdev;
1847	struct subchannel *sch;
1848	enum cdev_todo todo;
1849
1850	priv = container_of(work, struct ccw_device_private, todo_work);
1851	cdev = priv->cdev;
1852	sch = to_subchannel(cdev->dev.parent);
1853	/* Find out todo. */
1854	spin_lock_irq(cdev->ccwlock);
1855	todo = priv->todo;
1856	priv->todo = CDEV_TODO_NOTHING;
1857	CIO_MSG_EVENT(4, "cdev_todo: cdev=0.%x.%04x todo=%d\n",
1858		      priv->dev_id.ssid, priv->dev_id.devno, todo);
1859	spin_unlock_irq(cdev->ccwlock);
1860	/* Perform todo. */
1861	switch (todo) {
1862	case CDEV_TODO_ENABLE_CMF:
1863		cmf_reenable(cdev);
1864		break;
1865	case CDEV_TODO_REBIND:
1866		ccw_device_do_unbind_bind(cdev);
1867		break;
1868	case CDEV_TODO_REGISTER:
1869		io_subchannel_register(cdev);
1870		break;
1871	case CDEV_TODO_UNREG_EVAL:
1872		if (!sch_is_pseudo_sch(sch))
1873			css_schedule_eval(sch->schid);
1874		fallthrough;
1875	case CDEV_TODO_UNREG:
1876		spin_lock_irq(&sch->lock);
1877		sch_set_cdev(sch, NULL);
1878		spin_unlock_irq(&sch->lock);
1879		ccw_device_unregister(cdev);
1880		break;
1881	default:
1882		break;
1883	}
1884	/* Release workqueue ref. */
1885	put_device(&cdev->dev);
1886}
1887
1888/**
1889 * ccw_device_sched_todo - schedule ccw device operation
1890 * @cdev: ccw device
1891 * @todo: todo
1892 *
1893 * Schedule the operation identified by @todo to be performed on the slow path
1894 * workqueue. Do nothing if another operation with higher priority is already
1895 * scheduled. Needs to be called with ccwdev lock held.
1896 */
1897void ccw_device_sched_todo(struct ccw_device *cdev, enum cdev_todo todo)
1898{
1899	CIO_MSG_EVENT(4, "cdev_todo: sched cdev=0.%x.%04x todo=%d\n",
1900		      cdev->private->dev_id.ssid, cdev->private->dev_id.devno,
1901		      todo);
1902	if (cdev->private->todo >= todo)
1903		return;
1904	cdev->private->todo = todo;
1905	/* Get workqueue ref. */
1906	if (!get_device(&cdev->dev))
1907		return;
1908	if (!queue_work(cio_work_q, &cdev->private->todo_work)) {
1909		/* Already queued, release workqueue ref. */
1910		put_device(&cdev->dev);
1911	}
1912}
1913
1914/**
1915 * ccw_device_siosl() - initiate logging
1916 * @cdev: ccw device
1917 *
1918 * This function is used to invoke model-dependent logging within the channel
1919 * subsystem.
1920 */
1921int ccw_device_siosl(struct ccw_device *cdev)
1922{
1923	struct subchannel *sch = to_subchannel(cdev->dev.parent);
1924
1925	return chsc_siosl(sch->schid);
1926}
1927EXPORT_SYMBOL_GPL(ccw_device_siosl);
1928
1929EXPORT_SYMBOL(ccw_device_set_online);
1930EXPORT_SYMBOL(ccw_device_set_offline);
1931EXPORT_SYMBOL(ccw_driver_register);
1932EXPORT_SYMBOL(ccw_driver_unregister);
1933EXPORT_SYMBOL(get_ccwdev_by_busid);