1 files changed, 792 insertions, 0 deletions

diff --git a/drivers/s390/cio/chp.c b/drivers/s390/cio/chp.c
new file mode 100644
index 000000000..c692dfebd
--- /dev/null
+++ b/drivers/s390/cio/chp.c
@@ -0,0 +1,792 @@
+/*
+ *    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+/* Time after which channel-path status may be outdated.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\n") : sprintf(buf, "offline\n");
+}
+
+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 (!strncasecmp(cmd, "on", 2) || !strcmp(cmd, "1")) {
+		mutex_lock(&cp->lock);
+		error = s390_vary_chpid(cp->chpid, 1);
+		mutex_unlock(&cp->lock);
+	} else if (!strncasecmp(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\n", 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\n", 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\n");
+	return sprintf(buf, "%x\n", 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\n");
+	return sprintf(buf, "%x\n", 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\n", 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\n", 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\n",
+			      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.
+ */
+struct channel_path_desc *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\n",
+		      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\n", 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\n",
+			      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\n", 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\n", 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\n", 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\n", 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);