/*
   *    Copyright IBM Corp. 1999, 2010
   *    Author(s): Cornelia Huck (cornelia.huck@de.ibm.com)
   *		 Arnd Bergmann (arndb@de.ibm.com)
   *		 Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
   */
  
  #include <linux/bug.h>
  #include <linux/workqueue.h>
  #include <linux/spinlock.h>
  #include <linux/export.h>
  #include <linux/sched.h>
  #include <linux/init.h>
  #include <linux/jiffies.h>
  #include <linux/wait.h>
  #include <linux/mutex.h>
  #include <linux/errno.h>
  #include <linux/slab.h>
  #include <asm/chpid.h>
  #include <asm/sclp.h>
  #include <asm/crw.h>
  
  #include "cio.h"
  #include "css.h"
  #include "ioasm.h"
  #include "cio_debug.h"
  #include "chp.h"
  
  #define to_channelpath(device) container_of(device, struct channel_path, dev)
  #define CHP_INFO_UPDATE_INTERVAL	1*HZ
  
  enum cfg_task_t {
  	cfg_none,
  	cfg_configure,
  	cfg_deconfigure
  };
  
  /* Map for pending configure tasks. */
  static enum cfg_task_t chp_cfg_task[__MAX_CSSID + 1][__MAX_CHPID + 1];
  static DEFINE_MUTEX(cfg_lock);
  static int cfg_busy;
  
  /* Map for channel-path status. */
  static struct sclp_chp_info chp_info;
  static DEFINE_MUTEX(info_lock);
  
  /* Time after which channel-path status may be outdated. */
  static unsigned long chp_info_expires;
  
  /* Workqueue to perform pending configure tasks. */
  static struct workqueue_struct *chp_wq;
  static struct work_struct cfg_work;
  
  /* Wait queue for configure completion events. */
  static wait_queue_head_t cfg_wait_queue;
  
  /* Set vary state for given chpid. */
  static void set_chp_logically_online(struct chp_id chpid, int onoff)
  {
  	chpid_to_chp(chpid)->state = onoff;
  }
  
  /* On success return 0 if channel-path is varied offline, 1 if it is varied
   * online. Return -ENODEV if channel-path is not registered. */
  int chp_get_status(struct chp_id chpid)
  {
  	return (chpid_to_chp(chpid) ? chpid_to_chp(chpid)->state : -ENODEV);
  }
  
  /**
   * chp_get_sch_opm - return opm for subchannel
   * @sch: subchannel
   *
   * Calculate and return the operational path mask (opm) based on the chpids
   * used by the subchannel and the status of the associated channel-paths.
   */
  u8 chp_get_sch_opm(struct subchannel *sch)
  {
  	struct chp_id chpid;
  	int opm;
  	int i;
  
  	opm = 0;
  	chp_id_init(&chpid);
  	for (i = 0; i < 8; i++) {
  		opm <<= 1;
  		chpid.id = sch->schib.pmcw.chpid[i];
  		if (chp_get_status(chpid) != 0)
  			opm |= 1;
  	}
  	return opm;
  }
  EXPORT_SYMBOL_GPL(chp_get_sch_opm);
  
  /**
   * chp_is_registered - check if a channel-path is registered
   * @chpid: channel-path ID
   *
   * Return non-zero if a channel-path with the given chpid is registered,
   * zero otherwise.
   */
  int chp_is_registered(struct chp_id chpid)
  {
  	return chpid_to_chp(chpid) != NULL;
  }
  
  /*
   * Function: s390_vary_chpid
   * Varies the specified chpid online or offline
   */
  static int s390_vary_chpid(struct chp_id chpid, int on)
  {
  	char dbf_text[15];
  	int status;
  
  	sprintf(dbf_text, on?"varyon%x.%02x":"varyoff%x.%02x", chpid.cssid,
  		chpid.id);
  	CIO_TRACE_EVENT(2, dbf_text);
  
  	status = chp_get_status(chpid);
  	if (!on && !status)
  		return 0;
  
  	set_chp_logically_online(chpid, on);
  	chsc_chp_vary(chpid, on);
  	return 0;
  }
  
  /*
   * Channel measurement related functions
   */
  static ssize_t chp_measurement_chars_read(struct file *filp,
  					  struct kobject *kobj,
  					  struct bin_attribute *bin_attr,
  					  char *buf, loff_t off, size_t count)
  {
  	struct channel_path *chp;
  	struct device *device;
  
  	device = container_of(kobj, struct device, kobj);
  	chp = to_channelpath(device);
  	if (!chp->cmg_chars)
  		return 0;
  
  	return memory_read_from_buffer(buf, count, &off,
  				chp->cmg_chars, sizeof(struct cmg_chars));
  }
  
  static struct bin_attribute chp_measurement_chars_attr = {
  	.attr = {
  		.name = "measurement_chars",
  		.mode = S_IRUSR,
  	},
  	.size = sizeof(struct cmg_chars),
  	.read = chp_measurement_chars_read,
  };
  
  static void chp_measurement_copy_block(struct cmg_entry *buf,
  				       struct channel_subsystem *css,
  				       struct chp_id chpid)
  {
  	void *area;
  	struct cmg_entry *entry, reference_buf;
  	int idx;
  
  	if (chpid.id < 128) {
  		area = css->cub_addr1;
  		idx = chpid.id;
  	} else {
  		area = css->cub_addr2;
  		idx = chpid.id - 128;
  	}
  	entry = area + (idx * sizeof(struct cmg_entry));
  	do {
  		memcpy(buf, entry, sizeof(*entry));
  		memcpy(&reference_buf, entry, sizeof(*entry));
  	} while (reference_buf.values[0] != buf->values[0]);
  }
  
  static ssize_t chp_measurement_read(struct file *filp, struct kobject *kobj,
  				    struct bin_attribute *bin_attr,
  				    char *buf, loff_t off, size_t count)
  {
  	struct channel_path *chp;
  	struct channel_subsystem *css;
  	struct device *device;
  	unsigned int size;
  
  	device = container_of(kobj, struct device, kobj);
  	chp = to_channelpath(device);
  	css = to_css(chp->dev.parent);
  
  	size = sizeof(struct cmg_entry);
  
  	/* Only allow single reads. */
  	if (off || count < size)
  		return 0;
  	chp_measurement_copy_block((struct cmg_entry *)buf, css, chp->chpid);
  	count = size;
  	return count;
  }
  
  static struct bin_attribute chp_measurement_attr = {
  	.attr = {
  		.name = "measurement",
  		.mode = S_IRUSR,
  	},
  	.size = sizeof(struct cmg_entry),
  	.read = chp_measurement_read,
  };
  
  void chp_remove_cmg_attr(struct channel_path *chp)
  {
  	device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
  	device_remove_bin_file(&chp->dev, &chp_measurement_attr);
  }
  
  int chp_add_cmg_attr(struct channel_path *chp)
  {
  	int ret;
  
  	ret = device_create_bin_file(&chp->dev, &chp_measurement_chars_attr);
  	if (ret)
  		return ret;
  	ret = device_create_bin_file(&chp->dev, &chp_measurement_attr);
  	if (ret)
  		device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
  	return ret;
  }
  
  /*
   * Files for the channel path entries.
   */
  static ssize_t chp_status_show(struct device *dev,
  			       struct device_attribute *attr, char *buf)
  {
  	struct channel_path *chp = to_channelpath(dev);
  	int status;
  
  	mutex_lock(&chp->lock);
  	status = chp->state;
  	mutex_unlock(&chp->lock);
  
  	return status ? sprintf(buf, "online
  ") : sprintf(buf, "offline
  ");
  }
  
  static ssize_t chp_status_write(struct device *dev,
  				struct device_attribute *attr,
  				const char *buf, size_t count)
  {
  	struct channel_path *cp = to_channelpath(dev);
  	char cmd[10];
  	int num_args;
  	int error;
  
  	num_args = sscanf(buf, "%5s", cmd);
  	if (!num_args)
  		return count;
  
  	if (!strnicmp(cmd, "on", 2) || !strcmp(cmd, "1")) {
  		mutex_lock(&cp->lock);
  		error = s390_vary_chpid(cp->chpid, 1);
  		mutex_unlock(&cp->lock);
  	} else if (!strnicmp(cmd, "off", 3) || !strcmp(cmd, "0")) {
  		mutex_lock(&cp->lock);
  		error = s390_vary_chpid(cp->chpid, 0);
  		mutex_unlock(&cp->lock);
  	} else
  		error = -EINVAL;
  
  	return error < 0 ? error : count;
  }
  
  static DEVICE_ATTR(status, 0644, chp_status_show, chp_status_write);
  
  static ssize_t chp_configure_show(struct device *dev,
  				  struct device_attribute *attr, char *buf)
  {
  	struct channel_path *cp;
  	int status;
  
  	cp = to_channelpath(dev);
  	status = chp_info_get_status(cp->chpid);
  	if (status < 0)
  		return status;
  
  	return snprintf(buf, PAGE_SIZE, "%d
  ", status);
  }
  
  static int cfg_wait_idle(void);
  
  static ssize_t chp_configure_write(struct device *dev,
  				   struct device_attribute *attr,
  				   const char *buf, size_t count)
  {
  	struct channel_path *cp;
  	int val;
  	char delim;
  
  	if (sscanf(buf, "%d %c", &val, &delim) != 1)
  		return -EINVAL;
  	if (val != 0 && val != 1)
  		return -EINVAL;
  	cp = to_channelpath(dev);
  	chp_cfg_schedule(cp->chpid, val);
  	cfg_wait_idle();
  
  	return count;
  }
  
  static DEVICE_ATTR(configure, 0644, chp_configure_show, chp_configure_write);
  
  static ssize_t chp_type_show(struct device *dev, struct device_attribute *attr,
  			     char *buf)
  {
  	struct channel_path *chp = to_channelpath(dev);
  	u8 type;
  
  	mutex_lock(&chp->lock);
  	type = chp->desc.desc;
  	mutex_unlock(&chp->lock);
  	return sprintf(buf, "%x
  ", type);
  }
  
  static DEVICE_ATTR(type, 0444, chp_type_show, NULL);
  
  static ssize_t chp_cmg_show(struct device *dev, struct device_attribute *attr,
  			    char *buf)
  {
  	struct channel_path *chp = to_channelpath(dev);
  
  	if (!chp)
  		return 0;
  	if (chp->cmg == -1) /* channel measurements not available */
  		return sprintf(buf, "unknown
  ");
  	return sprintf(buf, "%x
  ", chp->cmg);
  }
  
  static DEVICE_ATTR(cmg, 0444, chp_cmg_show, NULL);
  
  static ssize_t chp_shared_show(struct device *dev,
  			       struct device_attribute *attr, char *buf)
  {
  	struct channel_path *chp = to_channelpath(dev);
  
  	if (!chp)
  		return 0;
  	if (chp->shared == -1) /* channel measurements not available */
  		return sprintf(buf, "unknown
  ");
  	return sprintf(buf, "%x
  ", chp->shared);
  }
  
  static DEVICE_ATTR(shared, 0444, chp_shared_show, NULL);
  
  static ssize_t chp_chid_show(struct device *dev, struct device_attribute *attr,
  			     char *buf)
  {
  	struct channel_path *chp = to_channelpath(dev);
  	ssize_t rc;
  
  	mutex_lock(&chp->lock);
  	if (chp->desc_fmt1.flags & 0x10)
  		rc = sprintf(buf, "%04x
  ", chp->desc_fmt1.chid);
  	else
  		rc = 0;
  	mutex_unlock(&chp->lock);
  
  	return rc;
  }
  static DEVICE_ATTR(chid, 0444, chp_chid_show, NULL);
  
  static ssize_t chp_chid_external_show(struct device *dev,
  				      struct device_attribute *attr, char *buf)
  {
  	struct channel_path *chp = to_channelpath(dev);
  	ssize_t rc;
  
  	mutex_lock(&chp->lock);
  	if (chp->desc_fmt1.flags & 0x10)
  		rc = sprintf(buf, "%x
  ", chp->desc_fmt1.flags & 0x8 ? 1 : 0);
  	else
  		rc = 0;
  	mutex_unlock(&chp->lock);
  
  	return rc;
  }
  static DEVICE_ATTR(chid_external, 0444, chp_chid_external_show, NULL);
  
  static struct attribute *chp_attrs[] = {
  	&dev_attr_status.attr,
  	&dev_attr_configure.attr,
  	&dev_attr_type.attr,
  	&dev_attr_cmg.attr,
  	&dev_attr_shared.attr,
  	&dev_attr_chid.attr,
  	&dev_attr_chid_external.attr,
  	NULL,
  };
  static struct attribute_group chp_attr_group = {
  	.attrs = chp_attrs,
  };
  static const struct attribute_group *chp_attr_groups[] = {
  	&chp_attr_group,
  	NULL,
  };
  
  static void chp_release(struct device *dev)
  {
  	struct channel_path *cp;
  
  	cp = to_channelpath(dev);
  	kfree(cp);
  }
  
  /**
   * chp_update_desc - update channel-path description
   * @chp - channel-path
   *
   * Update the channel-path description of the specified channel-path.
   * Return zero on success, non-zero otherwise.
   */
  int chp_update_desc(struct channel_path *chp)
  {
  	int rc;
  
  	rc = chsc_determine_base_channel_path_desc(chp->chpid, &chp->desc);
  	if (rc)
  		return rc;
  
  	rc = chsc_determine_fmt1_channel_path_desc(chp->chpid, &chp->desc_fmt1);
  
  	return rc;
  }
  
  /**
   * chp_new - register a new channel-path
   * @chpid - channel-path ID
   *
   * Create and register data structure representing new channel-path. Return
   * zero on success, non-zero otherwise.
   */
  int chp_new(struct chp_id chpid)
  {
  	struct channel_path *chp;
  	int ret;
  
  	if (chp_is_registered(chpid))
  		return 0;
  	chp = kzalloc(sizeof(struct channel_path), GFP_KERNEL);
  	if (!chp)
  		return -ENOMEM;
  
  	/* fill in status, etc. */
  	chp->chpid = chpid;
  	chp->state = 1;
  	chp->dev.parent = &channel_subsystems[chpid.cssid]->device;
  	chp->dev.groups = chp_attr_groups;
  	chp->dev.release = chp_release;
  	mutex_init(&chp->lock);
  
  	/* Obtain channel path description and fill it in. */
  	ret = chp_update_desc(chp);
  	if (ret)
  		goto out_free;
  	if ((chp->desc.flags & 0x80) == 0) {
  		ret = -ENODEV;
  		goto out_free;
  	}
  	/* Get channel-measurement characteristics. */
  	if (css_chsc_characteristics.scmc && css_chsc_characteristics.secm) {
  		ret = chsc_get_channel_measurement_chars(chp);
  		if (ret)
  			goto out_free;
  	} else {
  		chp->cmg = -1;
  	}
  	dev_set_name(&chp->dev, "chp%x.%02x", chpid.cssid, chpid.id);
  
  	/* make it known to the system */
  	ret = device_register(&chp->dev);
  	if (ret) {
  		CIO_MSG_EVENT(0, "Could not register chp%x.%02x: %d
  ",
  			      chpid.cssid, chpid.id, ret);
  		put_device(&chp->dev);
  		goto out;
  	}
  	mutex_lock(&channel_subsystems[chpid.cssid]->mutex);
  	if (channel_subsystems[chpid.cssid]->cm_enabled) {
  		ret = chp_add_cmg_attr(chp);
  		if (ret) {
  			device_unregister(&chp->dev);
  			mutex_unlock(&channel_subsystems[chpid.cssid]->mutex);
  			goto out;
  		}
  	}
  	channel_subsystems[chpid.cssid]->chps[chpid.id] = chp;
  	mutex_unlock(&channel_subsystems[chpid.cssid]->mutex);
  	goto out;
  out_free:
  	kfree(chp);
  out:
  	return ret;
  }
  
  /**
   * chp_get_chp_desc - return newly allocated channel-path description
   * @chpid: channel-path ID
   *
   * On success return a newly allocated copy of the channel-path description
   * data associated with the given channel-path ID. Return %NULL on error.
   */
  void *chp_get_chp_desc(struct chp_id chpid)
  {
  	struct channel_path *chp;
  	struct channel_path_desc *desc;
  
  	chp = chpid_to_chp(chpid);
  	if (!chp)
  		return NULL;
  	desc = kmalloc(sizeof(struct channel_path_desc), GFP_KERNEL);
  	if (!desc)
  		return NULL;
  
  	mutex_lock(&chp->lock);
  	memcpy(desc, &chp->desc, sizeof(struct channel_path_desc));
  	mutex_unlock(&chp->lock);
  	return desc;
  }
  
  /**
   * chp_process_crw - process channel-path status change
   * @crw0: channel report-word to handler
   * @crw1: second channel-report word (always NULL)
   * @overflow: crw overflow indication
   *
   * Handle channel-report-words indicating that the status of a channel-path
   * has changed.
   */
  static void chp_process_crw(struct crw *crw0, struct crw *crw1,
  			    int overflow)
  {
  	struct chp_id chpid;
  
  	if (overflow) {
  		css_schedule_eval_all();
  		return;
  	}
  	CIO_CRW_EVENT(2, "CRW reports slct=%d, oflw=%d, "
  		      "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X
  ",
  		      crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
  		      crw0->erc, crw0->rsid);
  	/*
  	 * Check for solicited machine checks. These are
  	 * created by reset channel path and need not be
  	 * handled here.
  	 */
  	if (crw0->slct) {
  		CIO_CRW_EVENT(2, "solicited machine check for "
  			      "channel path %02X
  ", crw0->rsid);
  		return;
  	}
  	chp_id_init(&chpid);
  	chpid.id = crw0->rsid;
  	switch (crw0->erc) {
  	case CRW_ERC_IPARM: /* Path has come. */
  		if (!chp_is_registered(chpid))
  			chp_new(chpid);
  		chsc_chp_online(chpid);
  		break;
  	case CRW_ERC_PERRI: /* Path has gone. */
  	case CRW_ERC_PERRN:
  		chsc_chp_offline(chpid);
  		break;
  	default:
  		CIO_CRW_EVENT(2, "Don't know how to handle erc=%x
  ",
  			      crw0->erc);
  	}
  }
  
  int chp_ssd_get_mask(struct chsc_ssd_info *ssd, struct chp_link *link)
  {
  	int i;
  	int mask;
  
  	for (i = 0; i < 8; i++) {
  		mask = 0x80 >> i;
  		if (!(ssd->path_mask & mask))
  			continue;
  		if (!chp_id_is_equal(&ssd->chpid[i], &link->chpid))
  			continue;
  		if ((ssd->fla_valid_mask & mask) &&
  		    ((ssd->fla[i] & link->fla_mask) != link->fla))
  			continue;
  		return mask;
  	}
  	return 0;
  }
  EXPORT_SYMBOL_GPL(chp_ssd_get_mask);
  
  static inline int info_bit_num(struct chp_id id)
  {
  	return id.id + id.cssid * (__MAX_CHPID + 1);
  }
  
  /* Force chp_info refresh on next call to info_validate(). */
  static void info_expire(void)
  {
  	mutex_lock(&info_lock);
  	chp_info_expires = jiffies - 1;
  	mutex_unlock(&info_lock);
  }
  
  /* Ensure that chp_info is up-to-date. */
  static int info_update(void)
  {
  	int rc;
  
  	mutex_lock(&info_lock);
  	rc = 0;
  	if (time_after(jiffies, chp_info_expires)) {
  		/* Data is too old, update. */
  		rc = sclp_chp_read_info(&chp_info);
  		chp_info_expires = jiffies + CHP_INFO_UPDATE_INTERVAL ;
  	}
  	mutex_unlock(&info_lock);
  
  	return rc;
  }
  
  /**
   * chp_info_get_status - retrieve configure status of a channel-path
   * @chpid: channel-path ID
   *
   * On success, return 0 for standby, 1 for configured, 2 for reserved,
   * 3 for not recognized. Return negative error code on error.
   */
  int chp_info_get_status(struct chp_id chpid)
  {
  	int rc;
  	int bit;
  
  	rc = info_update();
  	if (rc)
  		return rc;
  
  	bit = info_bit_num(chpid);
  	mutex_lock(&info_lock);
  	if (!chp_test_bit(chp_info.recognized, bit))
  		rc = CHP_STATUS_NOT_RECOGNIZED;
  	else if (chp_test_bit(chp_info.configured, bit))
  		rc = CHP_STATUS_CONFIGURED;
  	else if (chp_test_bit(chp_info.standby, bit))
  		rc = CHP_STATUS_STANDBY;
  	else
  		rc = CHP_STATUS_RESERVED;
  	mutex_unlock(&info_lock);
  
  	return rc;
  }
  
  /* Return configure task for chpid. */
  static enum cfg_task_t cfg_get_task(struct chp_id chpid)
  {
  	return chp_cfg_task[chpid.cssid][chpid.id];
  }
  
  /* Set configure task for chpid. */
  static void cfg_set_task(struct chp_id chpid, enum cfg_task_t cfg)
  {
  	chp_cfg_task[chpid.cssid][chpid.id] = cfg;
  }
  
  /* Perform one configure/deconfigure request. Reschedule work function until
   * last request. */
  static void cfg_func(struct work_struct *work)
  {
  	struct chp_id chpid;
  	enum cfg_task_t t;
  	int rc;
  
  	mutex_lock(&cfg_lock);
  	t = cfg_none;
  	chp_id_for_each(&chpid) {
  		t = cfg_get_task(chpid);
  		if (t != cfg_none) {
  			cfg_set_task(chpid, cfg_none);
  			break;
  		}
  	}
  	mutex_unlock(&cfg_lock);
  
  	switch (t) {
  	case cfg_configure:
  		rc = sclp_chp_configure(chpid);
  		if (rc)
  			CIO_MSG_EVENT(2, "chp: sclp_chp_configure(%x.%02x)="
  				      "%d
  ", chpid.cssid, chpid.id, rc);
  		else {
  			info_expire();
  			chsc_chp_online(chpid);
  		}
  		break;
  	case cfg_deconfigure:
  		rc = sclp_chp_deconfigure(chpid);
  		if (rc)
  			CIO_MSG_EVENT(2, "chp: sclp_chp_deconfigure(%x.%02x)="
  				      "%d
  ", chpid.cssid, chpid.id, rc);
  		else {
  			info_expire();
  			chsc_chp_offline(chpid);
  		}
  		break;
  	case cfg_none:
  		/* Get updated information after last change. */
  		info_update();
  		mutex_lock(&cfg_lock);
  		cfg_busy = 0;
  		mutex_unlock(&cfg_lock);
  		wake_up_interruptible(&cfg_wait_queue);
  		return;
  	}
  	queue_work(chp_wq, &cfg_work);
  }
  
  /**
   * chp_cfg_schedule - schedule chpid configuration request
   * @chpid - channel-path ID
   * @configure - Non-zero for configure, zero for deconfigure
   *
   * Schedule a channel-path configuration/deconfiguration request.
   */
  void chp_cfg_schedule(struct chp_id chpid, int configure)
  {
  	CIO_MSG_EVENT(2, "chp_cfg_sched%x.%02x=%d
  ", chpid.cssid, chpid.id,
  		      configure);
  	mutex_lock(&cfg_lock);
  	cfg_set_task(chpid, configure ? cfg_configure : cfg_deconfigure);
  	cfg_busy = 1;
  	mutex_unlock(&cfg_lock);
  	queue_work(chp_wq, &cfg_work);
  }
  
  /**
   * chp_cfg_cancel_deconfigure - cancel chpid deconfiguration request
   * @chpid - channel-path ID
   *
   * Cancel an active channel-path deconfiguration request if it has not yet
   * been performed.
   */
  void chp_cfg_cancel_deconfigure(struct chp_id chpid)
  {
  	CIO_MSG_EVENT(2, "chp_cfg_cancel:%x.%02x
  ", chpid.cssid, chpid.id);
  	mutex_lock(&cfg_lock);
  	if (cfg_get_task(chpid) == cfg_deconfigure)
  		cfg_set_task(chpid, cfg_none);
  	mutex_unlock(&cfg_lock);
  }
  
  static int cfg_wait_idle(void)
  {
  	if (wait_event_interruptible(cfg_wait_queue, !cfg_busy))
  		return -ERESTARTSYS;
  	return 0;
  }
  
  static int __init chp_init(void)
  {
  	struct chp_id chpid;
  	int ret;
  
  	ret = crw_register_handler(CRW_RSC_CPATH, chp_process_crw);
  	if (ret)
  		return ret;
  	chp_wq = create_singlethread_workqueue("cio_chp");
  	if (!chp_wq) {
  		crw_unregister_handler(CRW_RSC_CPATH);
  		return -ENOMEM;
  	}
  	INIT_WORK(&cfg_work, cfg_func);
  	init_waitqueue_head(&cfg_wait_queue);
  	if (info_update())
  		return 0;
  	/* Register available channel-paths. */
  	chp_id_for_each(&chpid) {
  		if (chp_info_get_status(chpid) != CHP_STATUS_NOT_RECOGNIZED)
  			chp_new(chpid);
  	}
  
  	return 0;
  }
  
  subsys_initcall(chp_init);