From: Hans-Joachim Picht <hpicht@redhat.com>
Date: Tue, 30 Oct 2007 17:03:07 +0100
Subject: [s390] cio: Dynamic CHPID reconfiguration via SCLP
Message-id: 20071030160307.GD6604@redhat.com
O-Subject: [RHEL5.2 PATCH 4/5] s390 cio: Dynamic CHPID reconfiguration via SCLP
Bugzilla: 253120

Problem:
=========

This patch enables the common I/O layer to:
- configure/deconfigure channel paths via SCLP by providing a 'configure'
  attribute per channel path object
- handle channel path configure events by triggering the requested channel
  path configure/deconfigure

Bugzilla
=========

BZ 253120
https://bugzilla.redhat.com/show_bug.cgi?id=253120

Upstream status of the patch:
=============================
Fix included in git as commit e5854a5839fa426a7873f038080f63587de5f1f1

Test status:
============
Kernel with patch was built and successfully tested

Please ACK.

With best regards,

Hans

diff --git a/drivers/s390/Kconfig b/drivers/s390/Kconfig
index bc4261e..080d64e 100644
--- a/drivers/s390/Kconfig
+++ b/drivers/s390/Kconfig
@@ -104,9 +104,8 @@ config CCW_CONSOLE
  	default y
  
 config SCLP
-	bool "Support for SCLP"
-	help
-	  Include support for the SCLP interface to the service element.
+	bool
+	default y
 
 config SCLP_TTY
 	bool "Support for SCLP line mode terminal"
diff --git a/drivers/s390/char/Makefile b/drivers/s390/char/Makefile
index 0c0162f..99d16d6 100644
--- a/drivers/s390/char/Makefile
+++ b/drivers/s390/char/Makefile
@@ -11,7 +11,7 @@ obj-$(CONFIG_TN3270_FS) += fs3270.o
 
 obj-$(CONFIG_TN3215) += con3215.o
 
-obj-$(CONFIG_SCLP) += sclp.o sclp_rw.o sclp_quiesce.o
+obj-$(CONFIG_SCLP) += sclp.o sclp_rw.o sclp_quiesce.o sclp_chp.o
 obj-$(CONFIG_SCLP_TTY) += sclp_tty.o
 obj-$(CONFIG_SCLP_CONSOLE) += sclp_con.o
 obj-$(CONFIG_SCLP_VT220_TTY) += sclp_vt220.o
diff --git a/drivers/s390/char/sclp.h b/drivers/s390/char/sclp.h
index 2c71d6e..1b38f75 100644
--- a/drivers/s390/char/sclp.h
+++ b/drivers/s390/char/sclp.h
@@ -14,6 +14,7 @@
 #include <linux/list.h>
 
 #include <asm/ebcdic.h>
+#include <asm/chpid.h>
 
 /* maximum number of pages concerning our own memory management */
 #define MAX_KMEM_PAGES (sizeof(unsigned long) << 3)
@@ -123,6 +124,18 @@ struct sclp_register {
 	void (*receiver_fn)(struct evbuf_header *);
 };
 
+#define SCLP_CHP_INFO_MASK_SIZE		32
+
+struct sclp_chp_info {
+	u8 recognized[SCLP_CHP_INFO_MASK_SIZE];
+	u8 standby[SCLP_CHP_INFO_MASK_SIZE];
+	u8 configured[SCLP_CHP_INFO_MASK_SIZE];
+};
+
+extern int sclp_chp_configure(struct chp_id chpid);
+extern int sclp_chp_deconfigure(struct chp_id chpid);
+extern int sclp_chp_read_info(struct sclp_chp_info *info);
+
 /* externals from sclp.c */
 int sclp_add_request(struct sclp_req *req);
 void sclp_sync_wait(void);
diff --git a/drivers/s390/char/sclp_chp.c b/drivers/s390/char/sclp_chp.c
new file mode 100644
index 0000000..eba3679
--- /dev/null
+++ b/drivers/s390/char/sclp_chp.c
@@ -0,0 +1,195 @@
+/*
+ *  drivers/s390/char/sclp_chp.c
+ *
+ *    Copyright IBM Corp. 2007
+ *    Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
+ */
+
+#include <linux/types.h>
+#include <linux/gfp.h>
+#include <linux/errno.h>
+#include <linux/completion.h>
+#include <asm/chpid.h>
+
+#include "sclp.h"
+
+#define TAG	"sclp_chp: "
+
+#define SCLP_CMDW_CONFIGURE_CHANNEL_PATH	0x000f0001
+#define SCLP_CMDW_DECONFIGURE_CHANNEL_PATH	0x000e0001
+#define SCLP_CMDW_READ_CHANNEL_PATH_INFORMATION	0x00030001
+
+static inline sclp_cmdw_t get_configure_cmdw(struct chp_id chpid)
+{
+	return SCLP_CMDW_CONFIGURE_CHANNEL_PATH | chpid.id << 8;
+}
+
+static inline sclp_cmdw_t get_deconfigure_cmdw(struct chp_id chpid)
+{
+	return SCLP_CMDW_DECONFIGURE_CHANNEL_PATH | chpid.id << 8;
+}
+
+static void chp_callback(struct sclp_req *req, void *data)
+{
+	struct completion *completion = data;
+
+	complete(completion);
+}
+
+struct chp_cfg_sccb {
+	struct sccb_header header;
+	u8 ccm;
+	u8 reserved[6];
+	u8 cssid;
+} __attribute__((packed));
+
+struct chp_cfg_data {
+	struct chp_cfg_sccb sccb;
+	struct sclp_req req;
+	struct completion completion;
+} __attribute__((packed));
+
+static int do_configure(sclp_cmdw_t cmd)
+{
+	struct chp_cfg_data *data;
+	int rc;
+
+	/* Prepare sccb. */
+	data = (struct chp_cfg_data *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
+	if (!data)
+		return -ENOMEM;
+	data->sccb.header.length = sizeof(struct chp_cfg_sccb);
+	data->req.command = cmd;
+	data->req.sccb = &(data->sccb);
+	data->req.status = SCLP_REQ_FILLED;
+	data->req.callback = chp_callback;
+	data->req.callback_data = &(data->completion);
+	init_completion(&data->completion);
+
+	/* Perform sclp request. */
+	rc = sclp_add_request(&(data->req));
+	if (rc)
+		goto out;
+	wait_for_completion(&data->completion);
+
+	/* Check response .*/
+	if (data->req.status != SCLP_REQ_DONE) {
+		printk(KERN_WARNING TAG "configure channel-path request failed "
+		       "(status=0x%02x)\n", data->req.status);
+		rc = -EIO;
+		goto out;
+	}
+	switch (data->sccb.header.response_code) {
+	case 0x0020:
+	case 0x0120:
+	case 0x0440:
+	case 0x0450:
+		break;
+	default:
+		printk(KERN_WARNING TAG "configure channel-path failed "
+		       "(cmd=0x%08x, response=0x%04x)\n", cmd,
+		       data->sccb.header.response_code);
+		rc = -EIO;
+		break;
+	}
+out:
+	free_page((unsigned long) data);
+
+	return rc;
+}
+
+/**
+ * sclp_chp_configure - perform configure channel-path sclp command
+ * @chpid: channel-path ID
+ *
+ * Perform configure channel-path command sclp command for specified chpid.
+ * Return 0 after command successfully finished, non-zero otherwise.
+ */
+int sclp_chp_configure(struct chp_id chpid)
+{
+	return do_configure(get_configure_cmdw(chpid));
+}
+
+/**
+ * sclp_chp_deconfigure - perform deconfigure channel-path sclp command
+ * @chpid: channel-path ID
+ *
+ * Perform deconfigure channel-path command sclp command for specified chpid
+ * and wait for completion. On success return 0. Return non-zero otherwise.
+ */
+int sclp_chp_deconfigure(struct chp_id chpid)
+{
+	return do_configure(get_deconfigure_cmdw(chpid));
+}
+
+struct chp_info_sccb {
+	struct sccb_header header;
+	u8 recognized[SCLP_CHP_INFO_MASK_SIZE];
+	u8 standby[SCLP_CHP_INFO_MASK_SIZE];
+	u8 configured[SCLP_CHP_INFO_MASK_SIZE];
+	u8 ccm;
+	u8 reserved[6];
+	u8 cssid;
+} __attribute__((packed));
+
+struct chp_info_data {
+	struct chp_info_sccb sccb;
+	struct sclp_req req;
+	struct completion completion;
+} __attribute__((packed));
+
+/**
+ * sclp_chp_read_info - perform read channel-path information sclp command
+ * @info: resulting channel-path information data
+ *
+ * Perform read channel-path information sclp command and wait for completion.
+ * On success, store channel-path information in @info and return 0. Return
+ * non-zero otherwise.
+ */
+int sclp_chp_read_info(struct sclp_chp_info *info)
+{
+	struct chp_info_data *data;
+	int rc;
+
+	/* Prepare sccb. */
+	data = (struct chp_info_data *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
+	if (!data)
+		return -ENOMEM;
+	data->sccb.header.length = sizeof(struct chp_info_sccb);
+	data->req.command = SCLP_CMDW_READ_CHANNEL_PATH_INFORMATION;
+	data->req.sccb = &(data->sccb);
+	data->req.status = SCLP_REQ_FILLED;
+	data->req.callback = chp_callback;
+	data->req.callback_data = &(data->completion);
+	init_completion(&data->completion);
+
+	/* Perform sclp request. */
+	rc = sclp_add_request(&(data->req));
+	if (rc)
+		goto out;
+	wait_for_completion(&data->completion);
+
+	/* Check response .*/
+	if (data->req.status != SCLP_REQ_DONE) {
+		printk(KERN_WARNING TAG "read channel-path info request failed "
+		       "(status=0x%02x)\n", data->req.status);
+		rc = -EIO;
+		goto out;
+	}
+	if (data->sccb.header.response_code != 0x0010) {
+		printk(KERN_WARNING TAG "read channel-path info failed "
+		       "(response=0x%04x)\n", data->sccb.header.response_code);
+		rc = -EIO;
+		goto out;
+	}
+	memcpy(info->recognized, data->sccb.recognized,
+	       SCLP_CHP_INFO_MASK_SIZE);
+	memcpy(info->standby, data->sccb.standby,
+	       SCLP_CHP_INFO_MASK_SIZE);
+	memcpy(info->configured, data->sccb.configured,
+	       SCLP_CHP_INFO_MASK_SIZE);
+out:
+	free_page((unsigned long) data);
+
+	return rc;
+}
diff --git a/drivers/s390/cio/Makefile b/drivers/s390/cio/Makefile
index c490c2a..fe7b3ff 100644
--- a/drivers/s390/cio/Makefile
+++ b/drivers/s390/cio/Makefile
@@ -2,7 +2,7 @@
 # Makefile for the S/390 common i/o drivers
 #
 
-obj-y += airq.o blacklist.o chsc.o cio.o css.o
+obj-y += airq.o blacklist.o chsc.o cio.o css.o chp.o
 ccw_device-objs += device.o device_fsm.o device_ops.o
 ccw_device-objs += device_id.o device_pgid.o device_status.o
 obj-y += ccw_device.o cmf.o
diff --git a/drivers/s390/cio/chp.c b/drivers/s390/cio/chp.c
new file mode 100644
index 0000000..b56e9d8
--- /dev/null
+++ b/drivers/s390/cio/chp.c
@@ -0,0 +1,687 @@
+/*
+ *  drivers/s390/cio/chp.c
+ *
+ *    Copyright IBM Corp. 1999,2007
+ *    Author(s): Cornelia Huck (cornelia.huck@de.ibm.com)
+ *		 Arnd Bergmann (arndb@de.ibm.com)
+ *		 Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
+ */
+
+#include <linux/workqueue.h>
+#include <linux/spinlock.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/wait.h>
+#include <linux/mutex.h>
+#include <linux/errno.h>
+#include <asm/chpid.h>
+
+#include "cio.h"
+#include "css.h"
+#include "ioasm.h"
+#include "cio_debug.h"
+#include "chp.h"
+
+#include "../char/sclp.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;
+
+/* Return channel_path struct for given chpid. */
+static inline struct channel_path *chpid_to_chp(struct chp_id chpid)
+{
+	return css[chpid.cssid]->chps[chpid.id];
+}
+
+/* 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 succes 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;
+}
+
+/**
+ * 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 (status < 0) {
+		printk(KERN_ERR "Can't vary unknown chpid %x.%02x\n",
+		       chpid.cssid, chpid.id);
+		return -EINVAL;
+	}
+
+	if (!on && !status) {
+		printk(KERN_ERR "chpid %x.%02x is already offline\n",
+		       chpid.cssid, chpid.id);
+		return -EINVAL;
+	}
+
+	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 kobject *kobj, char *buf,
+					  loff_t off, size_t count)
+{
+	struct channel_path *chp;
+	unsigned int size;
+
+	chp = to_channelpath(container_of(kobj, struct device, kobj));
+	if (!chp->cmg_chars)
+		return 0;
+
+	size = sizeof(struct cmg_chars);
+
+	if (off > size)
+		return 0;
+	if (off + count > size)
+		count = size - off;
+	memcpy(buf, chp->cmg_chars + off, count);
+	return count;
+}
+
+static struct bin_attribute chp_measurement_chars_attr = {
+	.attr = {
+		.name = "measurement_chars",
+		.mode = S_IRUSR,
+		.owner = THIS_MODULE,
+	},
+	.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 kobject *kobj, char *buf,
+				    loff_t off, size_t count)
+{
+	struct channel_path *chp;
+	struct channel_subsystem *css;
+	unsigned int size;
+
+	chp = to_channelpath(container_of(kobj, struct device, kobj));
+	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,
+		.owner = THIS_MODULE,
+	},
+	.size = sizeof(struct cmg_entry),
+	.read = chp_measurement_read,
+};
+
+void chp_remove_cmg_attr(struct channel_path *chp)
+{
+	sysfs_remove_bin_file(&chp->dev.kobj, &chp_measurement_chars_attr);
+	sysfs_remove_bin_file(&chp->dev.kobj, &chp_measurement_attr);
+}
+
+int chp_add_cmg_attr(struct channel_path *chp)
+{
+	int ret;
+
+	ret = sysfs_create_bin_file(&chp->dev.kobj,
+				    &chp_measurement_chars_attr);
+	if (ret)
+		return ret;
+	ret = sysfs_create_bin_file(&chp->dev.kobj, &chp_measurement_attr);
+	if (ret)
+		sysfs_remove_bin_file(&chp->dev.kobj,
+				      &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 = container_of(dev, struct channel_path, dev);
+
+	if (!chp)
+		return 0;
+	return (chp_get_status(chp->chpid) ? 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 = container_of(dev, struct channel_path, 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"))
+		error = s390_vary_chpid(cp->chpid, 1);
+	else if (!strnicmp(cmd, "off", 3) || !strcmp(cmd, "0"))
+		error = s390_vary_chpid(cp->chpid, 0);
+	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 = container_of(dev, struct channel_path, 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 = container_of(dev, struct channel_path, 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 = container_of(dev, struct channel_path, dev);
+
+	if (!chp)
+		return 0;
+	return sprintf(buf, "%x\n", chp->desc.desc);
+}
+
+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 struct attribute *chp_attrs[] = {
+	&dev_attr_status.attr,
+	&dev_attr_configure.attr,
+	&dev_attr_type.attr,
+	&dev_attr_cmg.attr,
+	&dev_attr_shared.attr,
+	NULL,
+};
+
+static struct attribute_group chp_attr_group = {
+	.attrs = chp_attrs,
+};
+
+static void chp_release(struct device *dev)
+{
+	struct channel_path *cp;
+
+	cp = container_of(dev, struct channel_path, dev);
+	kfree(cp);
+}
+
+/**
+ * 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 = &css[chpid.cssid]->device;
+	chp->dev.release = chp_release;
+	snprintf(chp->dev.bus_id, BUS_ID_SIZE, "chp%x.%02x", chpid.cssid,
+		 chpid.id);
+
+	/* Obtain channel path description and fill it in. */
+	ret = chsc_determine_channel_path_description(chpid, &chp->desc);
+	if (ret)
+		goto out_free;
+	if ((chp->desc.flags & 0x80) == 0) {
+		ret = -ENODEV;
+		goto out_free;
+	}
+	/* Get channel-measurement characteristics. */
+	if (css_characteristics_avail && css_chsc_characteristics.scmc
+	    && css_chsc_characteristics.secm) {
+		ret = chsc_get_channel_measurement_chars(chp);
+		if (ret)
+			goto out_free;
+	} else {
+		static int msg_done;
+
+		if (!msg_done) {
+			printk(KERN_WARNING "cio: Channel measurements not "
+			       "available, continuing.\n");
+			msg_done = 1;
+		}
+		chp->cmg = -1;
+	}
+
+	/* make it known to the system */
+	ret = device_register(&chp->dev);
+	if (ret) {
+		printk(KERN_WARNING "%s: could not register %x.%02x\n",
+		       __func__, chpid.cssid, chpid.id);
+		goto out_free;
+	}
+	ret = sysfs_create_group(&chp->dev.kobj, &chp_attr_group);
+	if (ret) {
+		device_unregister(&chp->dev);
+		goto out_free;
+	}
+	mutex_lock(&css[chpid.cssid]->mutex);
+	if (css[chpid.cssid]->cm_enabled) {
+		ret = chp_add_cmg_attr(chp);
+		if (ret) {
+			sysfs_remove_group(&chp->dev.kobj, &chp_attr_group);
+			device_unregister(&chp->dev);
+			mutex_unlock(&css[chpid.cssid]->mutex);
+			goto out_free;
+		}
+	}
+	css[chpid.cssid]->chps[chpid.id] = chp;
+	mutex_unlock(&css[chpid.cssid]->mutex);
+	return ret;
+out_free:
+	kfree(chp);
+	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;
+	memcpy(desc, &chp->desc, sizeof(struct channel_path_desc));
+	return desc;
+}
+
+/**
+ * chp_process_crw - process channel-path status change
+ * @id: channel-path ID number
+ * @status: non-zero if channel-path has become available, zero otherwise
+ *
+ * Handle channel-report-words indicating that the status of a channel-path
+ * has changed.
+ */
+int chp_process_crw(int id, int status)
+{
+	struct chp_id chpid;
+
+	chp_id_init(&chpid);
+	chpid.id = id;
+	if (status) {
+		if (!chp_is_registered(chpid))
+			chp_new(chpid);
+		return chsc_chp_online(chpid);
+	} else {
+		chsc_chp_offline(chpid);
+		return 0;
+	}
+}
+
+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(void *data)
+{
+	struct chp_id chpid;
+	enum cfg_task_t t;
+
+	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:
+		sclp_chp_configure(chpid);
+		info_expire();
+		chsc_chp_online(chpid);
+		break;
+	case cfg_deconfigure:
+		sclp_chp_deconfigure(chpid);
+		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;
+
+	chp_wq = create_singlethread_workqueue("cio_chp");
+	if (!chp_wq)
+		return -ENOMEM;
+	INIT_WORK(&cfg_work, cfg_func, NULL);
+	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);
diff --git a/drivers/s390/cio/chp.h b/drivers/s390/cio/chp.h
new file mode 100644
index 0000000..862af69
--- /dev/null
+++ b/drivers/s390/cio/chp.h
@@ -0,0 +1,53 @@
+/*
+ *  drivers/s390/cio/chp.h
+ *
+ *    Copyright IBM Corp. 2007
+ *    Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
+ */
+
+#ifndef S390_CHP_H
+#define S390_CHP_H S390_CHP_H
+
+#include <linux/types.h>
+#include <linux/device.h>
+#include <asm/chpid.h>
+#include "chsc.h"
+
+#define CHP_STATUS_STANDBY		0
+#define CHP_STATUS_CONFIGURED		1
+#define CHP_STATUS_RESERVED		2
+#define CHP_STATUS_NOT_RECOGNIZED	3
+
+static inline int chp_test_bit(u8 *bitmap, int num)
+{
+	int byte = num >> 3;
+	int mask = 128 >> (num & 7);
+
+	return (bitmap[byte] & mask) ? 1 : 0;
+}
+
+
+struct channel_path {
+	struct chp_id chpid;
+	int state;
+	struct channel_path_desc desc;
+	/* Channel-measurement related stuff: */
+	int cmg;
+	int shared;
+	void *cmg_chars;
+	struct device dev;
+};
+
+int chp_get_status(struct chp_id chpid);
+u8 chp_get_sch_opm(struct subchannel *sch);
+int chp_is_registered(struct chp_id chpid);
+void *chp_get_chp_desc(struct chp_id chpid);
+int chp_process_crw(int id, int available);
+void chp_remove_cmg_attr(struct channel_path *chp);
+int chp_add_cmg_attr(struct channel_path *chp);
+int chp_new(struct chp_id chpid);
+void chp_cfg_schedule(struct chp_id chpid, int configure);
+void chp_cfg_cancel_deconfigure(struct chp_id chpid);
+int chp_info_get_status(struct chp_id chpid);
+
+#endif /* S390_CHP_H */
diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c
index 9b58c5d..1310dbf 100644
--- a/drivers/s390/cio/chsc.c
+++ b/drivers/s390/cio/chsc.c
@@ -17,56 +17,18 @@
 #include <asm/cio.h>
 #include <asm/lowcore.h>
 #include <asm/ptrace.h>
+#include <asm/chpid.h>
 
 #include "css.h"
 #include "cio.h"
 #include "cio_debug.h"
 #include "ioasm.h"
+#include "chp.h"
 #include "chsc.h"
 #include "../s390mach.h"
 
 static void *sei_page;
 
-static int new_channel_path(int chpid);
-
-static inline void
-set_chp_logically_online(int chp, int onoff)
-{
-	css[0]->chps[chp]->state = onoff;
-}
-
-static int
-get_chp_status(int chp)
-{
-	return (css[0]->chps[chp] ? css[0]->chps[chp]->state : -ENODEV);
-}
-
-void
-chsc_validate_chpids(struct subchannel *sch)
-{
-	int mask, chp;
-
-	for (chp = 0; chp <= 7; chp++) {
-		mask = 0x80 >> chp;
-		if (!get_chp_status(sch->schib.pmcw.chpid[chp]))
-			/* disable using this path */
-			sch->opm &= ~mask;
-	}
-}
-
-void
-chpid_is_actually_online(int chp)
-{
-	int state;
-
-	state = get_chp_status(chp);
-	if (state < 0) {
-		need_rescan = 1;
-		queue_work(slow_path_wq, &slow_path_work);
-	} else
-		WARN_ON(!state);
-}
-
 /* FIXME: this is _always_ called for every subchannel. shouldn't we
  *	  process more than one at a time? */
 static int
@@ -203,14 +165,17 @@ css_get_ssd_info(struct subchannel *sch)
 	spin_unlock_irq(&sch->lock);
 	free_page((unsigned long)page);
 	if (!ret) {
-		int j, chpid, mask;
+		int j, mask;
+		struct chp_id chpid;
+
+		chp_id_init(&chpid);
 		/* Allocate channel path structures, if needed. */
 		for (j = 0; j < 8; j++) {
 			mask = 0x80 >> j;
-			chpid = sch->ssd_info.chpid[j];
+			chpid.id = sch->ssd_info.chpid[j];
 			if ((sch->schib.pmcw.pim & mask) &&
-			    (get_chp_status(chpid) < 0))
-			    new_channel_path(chpid);
+			    !chp_is_registered(chpid))
+				chp_new(chpid);
 		}
 	}
 	return ret;
@@ -222,7 +187,7 @@ s390_subchannel_remove_chpid(struct device *dev, void *data)
 	int j;
 	int mask;
 	struct subchannel *sch;
-	struct channel_path *chpid;
+	struct chp_id *chpid;
 	struct schib schib;
 
 	sch = to_subchannel(dev);
@@ -280,52 +245,48 @@ out_unreg:
 	return 0;
 }
 
-static inline void
-s390_set_chpid_offline( __u8 chpid)
+void chsc_chp_offline(struct chp_id chpid)
 {
 	char dbf_txt[15];
-	struct device *dev;
 
-	sprintf(dbf_txt, "chpr%x", chpid);
+	sprintf(dbf_txt, "chpr%x.%02x", chpid.cssid, chpid.id);
 	CIO_TRACE_EVENT(2, dbf_txt);
 
-	if (get_chp_status(chpid) <= 0)
+	if (chp_get_status(chpid) <= 0)
 		return;
-	dev = get_device(&css[0]->chps[chpid]->dev);
-	bus_for_each_dev(&css_bus_type, NULL, to_channelpath(dev),
+	bus_for_each_dev(&css_bus_type, NULL, &chpid,
 			 s390_subchannel_remove_chpid);
 
 	if (need_rescan || css_slow_subchannels_exist())
 		queue_work(slow_path_wq, &slow_path_work);
-	put_device(dev);
 }
 
 struct res_acc_data {
-	struct channel_path *chp;
+	struct chp_id chpid;
 	u32 fla_mask;
 	u16 fla;
 };
 
-static int
-s390_process_res_acc_sch(struct res_acc_data *res_data, struct subchannel *sch)
+static int s390_process_res_acc_sch(struct res_acc_data *res_data,
+				    struct subchannel *sch)
 {
 	int found;
 	int chp;
 	int ccode;
-	
+
 	found = 0;
 	for (chp = 0; chp <= 7; chp++)
 		/*
 		 * check if chpid is in information updated by ssd
 		 */
 		if (sch->ssd_info.valid &&
-		    sch->ssd_info.chpid[chp] == res_data->chp->id &&
+		    sch->ssd_info.chpid[chp] == res_data->chpid.id &&
 		    (sch->ssd_info.fla[chp] & res_data->fla_mask)
 		    == res_data->fla) {
 			found = 1;
 			break;
 		}
-	
+
 	if (found == 0)
 		return 0;
 
@@ -412,7 +373,8 @@ s390_process_res_acc (struct res_acc_data *res_data)
 	int rc;
 	char dbf_txt[15];
 
-	sprintf(dbf_txt, "accpr%x", res_data->chp->id);
+	sprintf(dbf_txt, "accpr%x.%02x", res_data->chpid.cssid,
+		res_data->chpid.id);
 	CIO_TRACE_EVENT( 2, dbf_txt);
 	if (res_data->fla != 0) {
 		sprintf(dbf_txt, "fla%x", res_data->fla);
@@ -464,29 +426,71 @@ __get_chpid_from_lir(void *data)
 	return (u16) (lir->indesc[0]&0x000000ff);
 }
 
+struct chp_config_data {
+	u8 map[32];
+	u8 op;
+	u8 pc;
+};
+
+struct chsc_sei_area {
+	struct chsc_header request;
+	u32 reserved1;
+	u32 reserved2;
+	u32 reserved3;
+	struct chsc_header response;
+	u32 reserved4;
+	u8  flags;
+	u8  vf;		/* validity flags */
+	u8  rs;		/* reporting source */
+	u8  cc;		/* content code */
+	u16 fla;	/* full link address */
+	u16 rsid;	/* reporting source id */
+	u32 reserved5;
+	u32 reserved6;
+	u32 ccdf[96];	/* content-code dependent field */
+	/* ccdf has to be big enough for a link-incident record */
+};
+
+static int chsc_process_sei_chp_config(struct chsc_sei_area *sei_area)
+{
+	struct chp_config_data *data;
+	struct chp_id chpid;
+	int num;
+
+	CIO_CRW_EVENT(4, "chsc: channel-path-configuration notification\n");
+	if (sei_area->rs != 0)
+		return 0;
+	data = (struct chp_config_data *) &(sei_area->ccdf);
+	chp_id_init(&chpid);
+	for (num = 0; num <= __MAX_CHPID; num++) {
+		if (!chp_test_bit(data->map, num))
+			continue;
+		chpid.id = num;
+		printk(KERN_WARNING "cio: processing configure event %d for "
+		       "chpid %x.%02x\n", data->op, chpid.cssid, chpid.id);
+		switch (data->op) {
+		case 0:
+			chp_cfg_schedule(chpid, 1);
+			break;
+		case 1:
+			chp_cfg_schedule(chpid, 0);
+			break;
+		case 2:
+			chp_cfg_cancel_deconfigure(chpid);
+			break;
+		}
+	}
+
+	return 0;
+}
+
 int
 chsc_process_crw(void)
 {
-	int chpid, ret;
+	struct chp_id chpid;
+	int id, ret;
 	struct res_acc_data res_data;
-	struct {
-		struct chsc_header request;
-		u32 reserved1;
-		u32 reserved2;
-		u32 reserved3;
-		struct chsc_header response;
-		u32 reserved4;
-		u8  flags;
-		u8  vf;		/* validity flags */
-		u8  rs;		/* reporting source */
-		u8  cc;		/* content code */
-		u16 fla;	/* full link address */
-		u16 rsid;	/* reporting source id */
-		u32 reserved5;
-		u32 reserved6;
-		u32 ccdf[96];	/* content-code dependent field */
-		/* ccdf has to be big enough for a link-incident record */
-	} *sei_area;
+	struct chsc_sei_area *sei_area;
 
 	if (!sei_page)
 		return 0;
@@ -502,7 +506,6 @@ chsc_process_crw(void)
 	ret = 0;
 	do {
 		int ccode, status;
-		struct device *dev;
 		memset(sei_area, 0, sizeof(*sei_area));
 		memset(&res_data, 0, sizeof(struct res_acc_data));
 		sei_area->request.length = 0x0010;
@@ -555,29 +558,32 @@ chsc_process_crw(void)
 				      "channel subsystem reports link incident,"
 				      " reporting source is chpid %x\n",
 				      sei_area->rsid);
-			chpid = __get_chpid_from_lir(sei_area->ccdf);
-			if (chpid < 0)
+			id = __get_chpid_from_lir(sei_area->ccdf);
+			if (id < 0)
 				CIO_CRW_EVENT(4, "%s: Invalid LIR, skipping\n",
 					      __FUNCTION__);
-			else
-				s390_set_chpid_offline(chpid);
+			else {
+				chp_id_init(&chpid);
+				chpid.id = id;
+				chsc_chp_offline(chpid);
+			}
 			break;
-			
+
 		case 2: /* i/o resource accessibiliy */
 			CIO_CRW_EVENT(4, "chsc_process_crw: "
 				      "channel subsystem reports some I/O "
 				      "devices may have become accessible\n");
 			pr_debug("Data received after sei: \n");
 			pr_debug("Validity flags: %x\n", sei_area->vf);
-			
+			chp_id_init(&chpid);
+			chpid.id = sei_area->rsid;
 			/* allocate a new channel path structure, if needed */
-			status = get_chp_status(sei_area->rsid);
+			status = chp_get_status(chpid);
 			if (status < 0)
-				new_channel_path(sei_area->rsid);
+				chp_new(chpid);
 			else if (!status)
 				break;
-			dev = get_device(&css[0]->chps[sei_area->rsid]->dev);
-			res_data.chp = to_channelpath(dev);
+			res_data.chpid = chpid;
 			pr_debug("chpid: %x", sei_area->rsid);
 			if ((sei_area->vf & 0xc0) != 0) {
 				res_data.fla = sei_area->fla;
@@ -593,9 +599,10 @@ chsc_process_crw(void)
 			}
 			ret = s390_process_res_acc(&res_data);
 			pr_debug("\n\n");
-			put_device(dev);
 			break;
-			
+		case 8: /* channel-path-configuration notification */
+			ret = chsc_process_sei_chp_config(sei_area);
+			break;
 		default: /* other stuff */
 			CIO_CRW_EVENT(4, "chsc_process_crw: event %d\n",
 				      sei_area->cc);
@@ -630,10 +637,10 @@ static int
 __chp_add(struct subchannel_id schid, void *data)
 {
 	int i, mask;
-	struct channel_path *chp;
+	struct chp_id *chpid;
 	struct subchannel *sch;
 
-	chp = (struct channel_path *)data;
+	chpid = data;
 	sch = get_subchannel_by_schid(schid);
 	if (!sch)
 		/* Check if the subchannel is now available. */
@@ -642,7 +649,7 @@ __chp_add(struct subchannel_id schid, void *data)
 	for (i=0; i<8; i++) {
 		mask = 0x80 >> i;
 		if ((sch->schib.pmcw.pim & mask) &&
-		    (sch->schib.pmcw.chpid[i] == chp->id)) {
+		    (sch->schib.pmcw.chpid[i] == chpid->id)) {
 			if (stsch(sch->schid, &sch->schib) != 0) {
 				/* Endgame. */
 				spin_unlock_irq(&sch->lock);
@@ -668,50 +675,24 @@ __chp_add(struct subchannel_id schid, void *data)
 	return 0;
 }
 
-static int
-chp_add(int chpid)
+int chsc_chp_online(struct chp_id chpid)
 {
 	int rc;
 	char dbf_txt[15];
-	struct device *dev;
 
-	if (!get_chp_status(chpid))
-		return 0; /* no need to do the rest */
-	
-	sprintf(dbf_txt, "cadd%x", chpid);
+	sprintf(dbf_txt, "cadd%x.%02x", chpid.cssid, chpid.id);
 	CIO_TRACE_EVENT(2, dbf_txt);
 
-	dev = get_device(&css[0]->chps[chpid]->dev);
-	rc = for_each_subchannel(__chp_add, to_channelpath(dev));
+	if (chp_get_status(chpid) == 0)
+		return 0;
+	rc = for_each_subchannel(__chp_add, &chpid);
 	if (css_slow_subchannels_exist())
 		rc = -EAGAIN;
 	if (rc != -EAGAIN)
 		rc = 0;
-	put_device(dev);
 	return rc;
 }
 
-/* 
- * Handling of crw machine checks with channel path source.
- */
-int
-chp_process_crw(int chpid, int on)
-{
-	if (on == 0) {
-		/* Path has gone. We use the link incident routine.*/
-		s390_set_chpid_offline(chpid);
-		return 0; /* De-register is async anyway. */
-	}
-	/*
-	 * Path has come. Allocate a new channel path structure,
-	 * if needed.
-	 */
-	if (get_chp_status(chpid) < 0)
-		new_channel_path(chpid);
-	/* Avoid the extra overhead in process_rec_acc. */
-	return chp_add(chpid);
-}
-
 static inline int
 check_for_io_on_path(struct subchannel *sch, int index)
 {
@@ -744,8 +725,8 @@ terminate_internal_io(struct subchannel *sch)
 		sch->driver->termination(&sch->dev);
 }
 
-static inline void
-__s390_subchannel_vary_chpid(struct subchannel *sch, __u8 chpid, int on)
+static void __s390_subchannel_vary_chpid(struct subchannel *sch,
+					 struct chp_id chpid, int on)
 {
 	int chp, old_lpm;
 	unsigned long flags;
@@ -756,7 +737,7 @@ __s390_subchannel_vary_chpid(struct subchannel *sch, __u8 chpid, int on)
 	spin_lock_irqsave(&sch->lock, flags);
 	old_lpm = sch->lpm;
 	for (chp = 0; chp < 8; chp++) {
-		if (sch->ssd_info.chpid[chp] != chpid)
+		if (sch->ssd_info.chpid[chp] != chpid.id)
 			continue;
 
 		if (on) {
@@ -794,11 +775,10 @@ __s390_subchannel_vary_chpid(struct subchannel *sch, __u8 chpid, int on)
 	spin_unlock_irqrestore(&sch->lock, flags);
 }
 
-static int
-s390_subchannel_vary_chpid_off(struct device *dev, void *data)
+static int s390_subchannel_vary_chpid_off(struct device *dev, void *data)
 {
 	struct subchannel *sch;
-	__u8 *chpid;
+	struct chp_id *chpid;
 
 	sch = to_subchannel(dev);
 	chpid = data;
@@ -807,11 +787,10 @@ s390_subchannel_vary_chpid_off(struct device *dev, void *data)
 	return 0;
 }
 
-static int
-s390_subchannel_vary_chpid_on(struct device *dev, void *data)
+static int s390_subchannel_vary_chpid_on(struct device *dev, void *data)
 {
 	struct subchannel *sch;
-	__u8 *chpid;
+	struct chp_id *chpid;
 
 	sch = to_subchannel(dev);
 	chpid = data;
@@ -843,32 +822,13 @@ __s390_vary_chpid_on(struct subchannel_id schid, void *data)
 	return 0;
 }
 
-/*
- * Function: s390_vary_chpid
- * Varies the specified chpid online or offline
+/**
+ * chsc_chp_vary - propagate channel-path vary operation to subchannels
+ * @chpid: channl-path ID
+ * @on: non-zero for vary online, zero for vary offline
  */
-static int
-s390_vary_chpid( __u8 chpid, int on)
+int chsc_chp_vary(struct chp_id chpid, int on)
 {
-	char dbf_text[15];
-	int status;
-
-	sprintf(dbf_text, on?"varyon%x":"varyoff%x", chpid);
-	CIO_TRACE_EVENT( 2, dbf_text);
-
-	status = get_chp_status(chpid);
-	if (status < 0) {
-		printk(KERN_ERR "Can't vary unknown chpid %02X\n", chpid);
-		return -EINVAL;
-	}
-
-	if (!on && !status) {
-		printk(KERN_ERR "chpid %x is already offline\n", chpid);
-		return -EINVAL;
-	}
-
-	set_chp_logically_online(chpid, on);
-
 	/*
 	 * Redo PathVerification on the devices the chpid connects to
 	 */
@@ -884,115 +844,6 @@ s390_vary_chpid( __u8 chpid, int on)
 	return 0;
 }
 
-/*
- * Channel measurement related functions
- */
-static ssize_t
-chp_measurement_chars_read(struct kobject *kobj, char *buf, loff_t off,
-			   size_t count)
-{
-	struct channel_path *chp;
-	unsigned int size;
-
-	chp = to_channelpath(container_of(kobj, struct device, kobj));
-	if (!chp->cmg_chars)
-		return 0;
-
-	size = sizeof(struct cmg_chars);
-
-	if (off > size)
-		return 0;
-	if (off + count > size)
-		count = size - off;
-	memcpy(buf, chp->cmg_chars + off, count);
-	return count;
-}
-
-static struct bin_attribute chp_measurement_chars_attr = {
-	.attr = {
-		.name = "measurement_chars",
-		.mode = S_IRUSR,
-		.owner = THIS_MODULE,
-	},
-	.size = sizeof(struct cmg_chars),
-	.read = chp_measurement_chars_read,
-};
-
-static void
-chp_measurement_copy_block(struct cmg_entry *buf,
-			   struct channel_subsystem *css, int chpid)
-{
-	void *area;
-	struct cmg_entry *entry, reference_buf;
-	int idx;
-
-	if (chpid < 128) {
-		area = css->cub_addr1;
-		idx = chpid;
-	} else {
-		area = css->cub_addr2;
-		idx = chpid - 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 kobject *kobj, char *buf, loff_t off, size_t count)
-{
-	struct channel_path *chp;
-	struct channel_subsystem *css;
-	unsigned int size;
-
-	chp = to_channelpath(container_of(kobj, struct device, kobj));
-	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->id);
-	count = size;
-	return count;
-}
-
-static struct bin_attribute chp_measurement_attr = {
-	.attr = {
-		.name = "measurement",
-		.mode = S_IRUSR,
-		.owner = THIS_MODULE,
-	},
-	.size = sizeof(struct cmg_entry),
-	.read = chp_measurement_read,
-};
-
-static void
-chsc_remove_chp_cmg_attr(struct channel_path *chp)
-{
-	sysfs_remove_bin_file(&chp->dev.kobj, &chp_measurement_chars_attr);
-	sysfs_remove_bin_file(&chp->dev.kobj, &chp_measurement_attr);
-}
-
-static int
-chsc_add_chp_cmg_attr(struct channel_path *chp)
-{
-	int ret;
-
-	ret = sysfs_create_bin_file(&chp->dev.kobj,
-				    &chp_measurement_chars_attr);
-	if (ret)
-		return ret;
-	ret = sysfs_create_bin_file(&chp->dev.kobj, &chp_measurement_attr);
-	if (ret)
-		sysfs_remove_bin_file(&chp->dev.kobj,
-				      &chp_measurement_chars_attr);
-	return ret;
-}
-
 static void
 chsc_remove_cmg_attr(struct channel_subsystem *css)
 {
@@ -1001,7 +852,7 @@ chsc_remove_cmg_attr(struct channel_subsystem *css)
 	for (i = 0; i <= __MAX_CHPID; i++) {
 		if (!css->chps[i])
 			continue;
-		chsc_remove_chp_cmg_attr(css->chps[i]);
+		chp_remove_cmg_attr(css->chps[i]);
 	}
 }
 
@@ -1014,7 +865,7 @@ chsc_add_cmg_attr(struct channel_subsystem *css)
 	for (i = 0; i <= __MAX_CHPID; i++) {
 		if (!css->chps[i])
 			continue;
-		ret = chsc_add_chp_cmg_attr(css->chps[i]);
+		ret = chp_add_cmg_attr(css->chps[i]);
 		if (ret)
 			goto cleanup;
 	}
@@ -1023,12 +874,11 @@ cleanup:
 	for (--i; i >= 0; i--) {
 		if (!css->chps[i])
 			continue;
-		chsc_remove_chp_cmg_attr(css->chps[i]);
+		chp_remove_cmg_attr(css->chps[i]);
 	}
 	return ret;
 }
 
-
 static int
 __chsc_do_secm(struct channel_subsystem *css, int enable, void *page)
 {
@@ -1143,109 +993,8 @@ chsc_secm(struct channel_subsystem *css, int enable)
 	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 = container_of(dev, struct channel_path, dev);
-
-	if (!chp)
-		return 0;
-	return (get_chp_status(chp->id) ? 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 = container_of(dev, struct channel_path, 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))
-		error = s390_vary_chpid(cp->id, 1);
-	else if (!strnicmp(cmd, "off", 3))
-		error = s390_vary_chpid(cp->id, 0);
-	else
-		error = -EINVAL;
-
-	return error < 0 ? error : count;
-
-}
-
-static DEVICE_ATTR(status, 0644, chp_status_show, chp_status_write);
-
-static ssize_t
-chp_type_show(struct device *dev, struct device_attribute *attr, char *buf)
-{
-	struct channel_path *chp = container_of(dev, struct channel_path, dev);
-
-	if (!chp)
-		return 0;
-	return sprintf(buf, "%x\n", chp->desc.desc);
-}
-
-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 struct attribute * chp_attrs[] = {
-	&dev_attr_status.attr,
-	&dev_attr_type.attr,
-	&dev_attr_cmg.attr,
-	&dev_attr_shared.attr,
-	NULL,
-};
-
-static struct attribute_group chp_attr_group = {
-	.attrs = chp_attrs,
-};
-
-static void
-chp_release(struct device *dev)
-{
-	struct channel_path *cp;
-	
-	cp = container_of(dev, struct channel_path, dev);
-	kfree(cp);
-}
-
-static int
-chsc_determine_channel_path_description(int chpid,
-					struct channel_path_desc *desc)
+int chsc_determine_channel_path_description(struct chp_id chpid,
+					    struct channel_path_desc *desc)
 {
 	int ccode, ret;
 
@@ -1268,8 +1017,8 @@ chsc_determine_channel_path_description(int chpid,
 	scpd_area->request.length = 0x0010;
 	scpd_area->request.code = 0x0002;
 
-	scpd_area->first_chpid = chpid;
-	scpd_area->last_chpid = chpid;
+	scpd_area->first_chpid = chpid.id;
+	scpd_area->last_chpid = chpid.id;
 
 	ccode = chsc(scpd_area);
 	if (ccode > 0) {
@@ -1332,8 +1081,7 @@ chsc_initialize_cmg_chars(struct channel_path *chp, u8 cmcv,
 	}
 }
 
-static int
-chsc_get_channel_measurement_chars(struct channel_path *chp)
+int chsc_get_channel_measurement_chars(struct channel_path *chp)
 {
 	int ccode, ret;
 
@@ -1365,8 +1113,8 @@ chsc_get_channel_measurement_chars(struct channel_path *chp)
 	scmc_area->request.length = 0x0010;
 	scmc_area->request.code = 0x0022;
 
-	scmc_area->first_chpid = chp->id;
-	scmc_area->last_chpid = chp->id;
+	scmc_area->first_chpid = chp->chpid.id;
+	scmc_area->last_chpid = chp->chpid.id;
 
 	ccode = chsc(scmc_area);
 	if (ccode > 0) {
@@ -1408,99 +1156,11 @@ out:
 	return ret;
 }
 
-/*
- * Entries for chpids on the system bus.
- * This replaces /proc/chpids.
- */
-static int
-new_channel_path(int chpid)
-{
-	struct channel_path *chp;
-	int ret;
-
-	chp = kzalloc(sizeof(struct channel_path), GFP_KERNEL);
-	if (!chp)
-		return -ENOMEM;
-
-	/* fill in status, etc. */
-	chp->id = chpid;
-	chp->state = 1;
-	chp->dev.parent = &css[0]->device;
-	chp->dev.release = chp_release;
-	snprintf(chp->dev.bus_id, BUS_ID_SIZE, "chp0.%x", chpid);
-
-	/* Obtain channel path description and fill it in. */
-	ret = chsc_determine_channel_path_description(chpid, &chp->desc);
-	if (ret)
-		goto out_free;
-	/* Get channel-measurement characteristics. */
-	if (css_characteristics_avail && css_chsc_characteristics.scmc
-	    && css_chsc_characteristics.secm) {
-		ret = chsc_get_channel_measurement_chars(chp);
-		if (ret)
-			goto out_free;
-	} else {
-		static int msg_done;
-
-		if (!msg_done) {
-			printk(KERN_WARNING "cio: Channel measurements not "
-			       "available, continuing.\n");
-			msg_done = 1;
-		}
-		chp->cmg = -1;
-	}
-
-	/* make it known to the system */
-	ret = device_register(&chp->dev);
-	if (ret) {
-		printk(KERN_WARNING "%s: could not register %02x\n",
-		       __func__, chpid);
-		goto out_free;
-	}
-	ret = sysfs_create_group(&chp->dev.kobj, &chp_attr_group);
-	if (ret) {
-		device_unregister(&chp->dev);
-		goto out_free;
-	}
-	mutex_lock(&css[0]->mutex);
-	if (css[0]->cm_enabled) {
-		ret = chsc_add_chp_cmg_attr(chp);
-		if (ret) {
-			sysfs_remove_group(&chp->dev.kobj, &chp_attr_group);
-			device_unregister(&chp->dev);
-			mutex_unlock(&css[0]->mutex);
-			goto out_free;
-		}
-	}
-	css[0]->chps[chpid] = chp;
-	mutex_unlock(&css[0]->mutex);
-	return ret;
-out_free:
-	kfree(chp);
-	return ret;
-}
-
-void *
-chsc_get_chp_desc(struct subchannel *sch, int chp_no)
-{
-	struct channel_path *chp;
-	struct channel_path_desc *desc;
-
-	chp = css[0]->chps[sch->schib.pmcw.chpid[chp_no]];
-	if (!chp)
-		return NULL;
-	desc = kmalloc(sizeof(struct channel_path_desc), GFP_KERNEL);
-	if (!desc)
-		return NULL;
-	memcpy(desc, &chp->desc, sizeof(struct channel_path_desc));
-	return desc;
-}
-
 static int reset_channel_path(struct channel_path *chp)
 {
 	int cc;
 
-	cc = rchp(chp->id);
+	cc = rchp(chp->chpid);
 	switch (cc) {
 	case 0:
 		return 0;
diff --git a/drivers/s390/cio/chsc.h b/drivers/s390/cio/chsc.h
index a259245..662e16d 100644
--- a/drivers/s390/cio/chsc.h
+++ b/drivers/s390/cio/chsc.h
@@ -1,9 +1,9 @@
 #ifndef S390_CHSC_H
 #define S390_CHSC_H
 
-#define CHSC_SEI_ACC_CHPID        1
-#define CHSC_SEI_ACC_LINKADDR     2
-#define CHSC_SEI_ACC_FULLLINKADDR 3
+#include <linux/types.h>
+#include <linux/device.h>
+#include <asm/chpid.h>
 
 #define CHSC_SDA_OC_MSS   0x2
 
@@ -33,20 +33,9 @@ struct channel_path_desc {
 	u8 chpp;
 };
 
-struct channel_path {
-	int id;
-	int state;
-	struct channel_path_desc desc;
-	/* Channel-measurement related stuff: */
-	int cmg;
-	int shared;
-	void *cmg_chars;
-	struct device dev;
-};
+struct channel_path;
 
 extern void s390_process_css( void );
-extern void chsc_validate_chpids(struct subchannel *);
-extern void chpid_is_actually_online(int);
 
 struct css_general_char {
 	u64 : 41;
@@ -82,12 +71,15 @@ extern struct css_chsc_char css_chsc_characteristics;
 extern int chsc_determine_css_characteristics(void);
 extern int css_characteristics_avail;
 
-extern void *chsc_get_chp_desc(struct subchannel*, int);
-
 extern int chsc_enable_facility(int);
 struct channel_subsystem;
 extern int chsc_secm(struct channel_subsystem *, int);
 
-#define to_channelpath(device) container_of(device, struct channel_path, dev)
+int chsc_chp_vary(struct chp_id chpid, int on);
+int chsc_determine_channel_path_description(struct chp_id chpid,
+					    struct channel_path_desc *desc);
+int chsc_chp_online(struct chp_id chpid);
+void chsc_chp_offline(struct chp_id chpid);
+int chsc_get_channel_measurement_chars(struct channel_path *chp);
 
 #endif
diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c
index 75f44c7..78a8b34 100644
--- a/drivers/s390/cio/cio.c
+++ b/drivers/s390/cio/cio.c
@@ -20,6 +20,7 @@
 #include <asm/cio.h>
 #include <asm/delay.h>
 #include <asm/irq.h>
+#include <asm/chpid.h>
 
 #include "airq.h"
 #include "cio.h"
@@ -28,6 +29,7 @@
 #include "ioasm.h"
 #include "blacklist.h"
 #include "cio_debug.h"
+#include "chp.h"
 
 debug_info_t *cio_debug_msg_id;
 debug_info_t *cio_debug_trace_id;
@@ -567,9 +569,10 @@ cio_validate_subchannel (struct subchannel *sch, struct subchannel_id schid)
 			      sch->schib.pmcw.dev, sch->schid.ssid);
 		return -ENODEV;
 	}
-	sch->opm = 0xff;
-	if (!cio_is_console(sch->schid))
-		chsc_validate_chpids(sch);
+	if (cio_is_console(sch->schid))
+		sch->opm = 0xff;
+	else
+		sch->opm = chp_get_sch_opm(sch);
 	sch->lpm = sch->schib.pmcw.pam & sch->opm;
 
 	CIO_DEBUG(KERN_INFO, 0,
diff --git a/drivers/s390/cio/cio.h b/drivers/s390/cio/cio.h
index 4541c1a..adb1dce 100644
--- a/drivers/s390/cio/cio.h
+++ b/drivers/s390/cio/cio.h
@@ -3,6 +3,7 @@
 
 #include "schid.h"
 #include <linux/mutex.h>
+#include <linux/device.h>
 
 /*
  * where we put the ssd info
diff --git a/drivers/s390/cio/css.h b/drivers/s390/cio/css.h
index db9ff50..ced4216 100644
--- a/drivers/s390/cio/css.h
+++ b/drivers/s390/cio/css.h
@@ -4,8 +4,11 @@
 #include <linux/mutex.h>
 #include <linux/wait.h>
 #include <linux/workqueue.h>
+#include <linux/device.h>
+#include <linux/types.h>
 
 #include <asm/cio.h>
+#include <asm/chpid.h>
 
 #include "schid.h"
 
@@ -145,8 +148,6 @@ extern int for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *);
 
 #define __MAX_SUBCHANNEL 65535
 #define __MAX_SSID 3
-#define __MAX_CHPID 255
-#define __MAX_CSSID 0
 
 struct channel_subsystem {
 	u8 cssid;
diff --git a/drivers/s390/cio/device_fsm.c b/drivers/s390/cio/device_fsm.c
index 9b1e1ff..8872ac7 100644
--- a/drivers/s390/cio/device_fsm.c
+++ b/drivers/s390/cio/device_fsm.c
@@ -15,6 +15,7 @@
 
 #include <asm/ccwdev.h>
 #include <asm/cio.h>
+#include <asm/chpid.h>
 
 #include "cio.h"
 #include "cio_debug.h"
@@ -22,6 +23,7 @@
 #include "device.h"
 #include "chsc.h"
 #include "ioasm.h"
+#include "chp.h"
 
 int
 device_is_online(struct subchannel *sch)
@@ -214,14 +216,20 @@ static inline void
 __recover_lost_chpids(struct subchannel *sch, int old_lpm)
 {
 	int mask, i;
+	struct chp_id chpid;
 
+	chp_id_init(&chpid);
 	for (i = 0; i<8; i++) {
 		mask = 0x80 >> i;
 		if (!(sch->lpm & mask))
 			continue;
 		if (old_lpm & mask)
 			continue;
-		chpid_is_actually_online(sch->schib.pmcw.chpid[i]);
+		chpid.id = sch->schib.pmcw.chpid[i];
+		if (!chp_is_registered(chpid)) {
+			need_rescan = 1;
+			queue_work(slow_path_wq, &slow_path_work);
+		}
 	}
 }
 
diff --git a/drivers/s390/cio/device_ops.c b/drivers/s390/cio/device_ops.c
index e8f33da..61fc5da 100644
--- a/drivers/s390/cio/device_ops.c
+++ b/drivers/s390/cio/device_ops.c
@@ -16,12 +16,14 @@
 
 #include <asm/ccwdev.h>
 #include <asm/idals.h>
+#include <asm/chpid.h>
 
 #include "cio.h"
 #include "cio_debug.h"
 #include "css.h"
 #include "chsc.h"
 #include "device.h"
+#include "chp.h"
 
 int
 ccw_device_set_options(struct ccw_device *cdev, unsigned long flags)
@@ -582,9 +584,12 @@ void *
 ccw_device_get_chp_desc(struct ccw_device *cdev, int chp_no)
 {
 	struct subchannel *sch;
+	struct chp_id chpid;
 
 	sch = to_subchannel(cdev->dev.parent);
-	return chsc_get_chp_desc(sch, chp_no);
+	chp_id_init(&chpid);
+	chpid.id = sch->schib.pmcw.chpid[chp_no];
+	return chp_get_chp_desc(chpid);
 }
 
 // FIXME: these have to go:
diff --git a/drivers/s390/cio/ioasm.h b/drivers/s390/cio/ioasm.h
index 95a9462..27475a1 100644
--- a/drivers/s390/cio/ioasm.h
+++ b/drivers/s390/cio/ioasm.h
@@ -1,6 +1,7 @@
 #ifndef S390_CIO_IOASM_H
 #define S390_CIO_IOASM_H
 
+#include <asm/chpid.h>
 #include "schid.h"
 
 /*
@@ -246,7 +247,7 @@ static inline int iac( void)
 	return ccode;
 }
 
-static inline int rchp(int chpid)
+static inline int rchp(struct chp_id chpid)
 {
 	int ccode;
 
diff --git a/include/asm-s390/chpid.h b/include/asm-s390/chpid.h
new file mode 100644
index 0000000..b203336
--- /dev/null
+++ b/include/asm-s390/chpid.h
@@ -0,0 +1,53 @@
+/*
+ *  drivers/s390/cio/chpid.h
+ *
+ *    Copyright IBM Corp. 2007
+ *    Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
+ */
+
+#ifndef _ASM_S390_CHPID_H
+#define _ASM_S390_CHPID_H _ASM_S390_CHPID_H
+
+#include <linux/string.h>
+#include <asm/types.h>
+#include <asm/cio.h>
+
+#define __MAX_CHPID 255
+
+struct chp_id {
+	u8 reserved1;
+	u8 cssid;
+	u8 reserved2;
+	u8 id;
+} __attribute__((packed));
+
+static inline void chp_id_init(struct chp_id *chpid)
+{
+	memset(chpid, 0, sizeof(struct chp_id));
+}
+
+static inline int chp_id_is_equal(struct chp_id *a, struct chp_id *b)
+{
+	return (a->id == b->id) && (a->cssid == b->cssid);
+}
+
+static inline void chp_id_next(struct chp_id *chpid)
+{
+	if (chpid->id < __MAX_CHPID)
+		chpid->id++;
+	else {
+		chpid->id = 0;
+		chpid->cssid++;
+	}
+}
+
+static inline int chp_id_is_valid(struct chp_id *chpid)
+{
+	return (chpid->cssid <= __MAX_CSSID);
+}
+
+
+#define chp_id_for_each(c) \
+	for (chp_id_init(c); chp_id_is_valid(c); chp_id_next(c))
+
+#endif /* _ASM_S390_CHPID_H */
diff --git a/include/asm-s390/cio.h b/include/asm-s390/cio.h
index 2802435..0f6a09b 100644
--- a/include/asm-s390/cio.h
+++ b/include/asm-s390/cio.h
@@ -13,6 +13,7 @@
 #ifdef __KERNEL__
 
 #define LPM_ANYPATH 0xff
+#define __MAX_CSSID 0
 
 /*
  * subchannel status word