Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1906 insertions, 0 deletions

diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
new file mode 100644
index 0000000000..4ca5adce91
--- /dev/null
+++ b/drivers/s390/cio/device.c
@@ -0,0 +1,1906 @@
+// SPDX-License-Identifier: GPL-1.0+
+/*
+ *  bus driver for ccw devices
+ *
+ *    Copyright IBM Corp. 2002, 2008
+ *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
+ *		 Cornelia Huck (cornelia.huck@de.ibm.com)
+ *		 Martin Schwidefsky (schwidefsky@de.ibm.com)
+ */
+
+#define KMSG_COMPONENT "cio"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/device.h>
+#include <linux/workqueue.h>
+#include <linux/delay.h>
+#include <linux/timer.h>
+#include <linux/kernel_stat.h>
+#include <linux/sched/signal.h>
+#include <linux/dma-mapping.h>
+
+#include <asm/ccwdev.h>
+#include <asm/cio.h>
+#include <asm/param.h>		/* HZ */
+#include <asm/cmb.h>
+#include <asm/isc.h>
+
+#include "chp.h"
+#include "cio.h"
+#include "cio_debug.h"
+#include "css.h"
+#include "device.h"
+#include "ioasm.h"
+#include "io_sch.h"
+#include "blacklist.h"
+#include "chsc.h"
+
+static struct timer_list recovery_timer;
+static DEFINE_SPINLOCK(recovery_lock);
+static int recovery_phase;
+static const unsigned long recovery_delay[] = { 3, 30, 300 };
+
+static atomic_t ccw_device_init_count = ATOMIC_INIT(0);
+static DECLARE_WAIT_QUEUE_HEAD(ccw_device_init_wq);
+static struct bus_type ccw_bus_type;
+
+/******************* bus type handling ***********************/
+
+/* The Linux driver model distinguishes between a bus type and
+ * the bus itself. Of course we only have one channel
+ * subsystem driver and one channel system per machine, but
+ * we still use the abstraction. T.R. says it's a good idea. */
+static int
+ccw_bus_match (struct device * dev, struct device_driver * drv)
+{
+	struct ccw_device *cdev = to_ccwdev(dev);
+	struct ccw_driver *cdrv = to_ccwdrv(drv);
+	const struct ccw_device_id *ids = cdrv->ids, *found;
+
+	if (!ids)
+		return 0;
+
+	found = ccw_device_id_match(ids, &cdev->id);
+	if (!found)
+		return 0;
+
+	cdev->id.driver_info = found->driver_info;
+
+	return 1;
+}
+
+/* Store modalias string delimited by prefix/suffix string into buffer with
+ * specified size. Return length of resulting string (excluding trailing '\0')
+ * even if string doesn't fit buffer (snprintf semantics). */
+static int snprint_alias(char *buf, size_t size,
+			 const struct ccw_device_id *id, const char *suffix)
+{
+	int len;
+
+	len = snprintf(buf, size, "ccw:t%04Xm%02X", id->cu_type, id->cu_model);
+	if (len > size)
+		return len;
+	buf += len;
+	size -= len;
+
+	if (id->dev_type != 0)
+		len += snprintf(buf, size, "dt%04Xdm%02X%s", id->dev_type,
+				id->dev_model, suffix);
+	else
+		len += snprintf(buf, size, "dtdm%s", suffix);
+
+	return len;
+}
+
+/* Set up environment variables for ccw device uevent. Return 0 on success,
+ * non-zero otherwise. */
+static int ccw_uevent(const struct device *dev, struct kobj_uevent_env *env)
+{
+	const struct ccw_device *cdev = to_ccwdev(dev);
+	const struct ccw_device_id *id = &(cdev->id);
+	int ret;
+	char modalias_buf[30];
+
+	/* CU_TYPE= */
+	ret = add_uevent_var(env, "CU_TYPE=%04X", id->cu_type);
+	if (ret)
+		return ret;
+
+	/* CU_MODEL= */
+	ret = add_uevent_var(env, "CU_MODEL=%02X", id->cu_model);
+	if (ret)
+		return ret;
+
+	/* The next two can be zero, that's ok for us */
+	/* DEV_TYPE= */
+	ret = add_uevent_var(env, "DEV_TYPE=%04X", id->dev_type);
+	if (ret)
+		return ret;
+
+	/* DEV_MODEL= */
+	ret = add_uevent_var(env, "DEV_MODEL=%02X", id->dev_model);
+	if (ret)
+		return ret;
+
+	/* MODALIAS=  */
+	snprint_alias(modalias_buf, sizeof(modalias_buf), id, "");
+	ret = add_uevent_var(env, "MODALIAS=%s", modalias_buf);
+	return ret;
+}
+
+static void io_subchannel_irq(struct subchannel *);
+static int io_subchannel_probe(struct subchannel *);
+static void io_subchannel_remove(struct subchannel *);
+static void io_subchannel_shutdown(struct subchannel *);
+static int io_subchannel_sch_event(struct subchannel *, int);
+static int io_subchannel_chp_event(struct subchannel *, struct chp_link *,
+				   int);
+static void recovery_func(struct timer_list *unused);
+
+static struct css_device_id io_subchannel_ids[] = {
+	{ .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
+	{ /* end of list */ },
+};
+
+static int io_subchannel_settle(void)
+{
+	int ret;
+
+	ret = wait_event_interruptible(ccw_device_init_wq,
+				atomic_read(&ccw_device_init_count) == 0);
+	if (ret)
+		return -EINTR;
+	flush_workqueue(cio_work_q);
+	return 0;
+}
+
+static struct css_driver io_subchannel_driver = {
+	.drv = {
+		.owner = THIS_MODULE,
+		.name = "io_subchannel",
+	},
+	.subchannel_type = io_subchannel_ids,
+	.irq = io_subchannel_irq,
+	.sch_event = io_subchannel_sch_event,
+	.chp_event = io_subchannel_chp_event,
+	.probe = io_subchannel_probe,
+	.remove = io_subchannel_remove,
+	.shutdown = io_subchannel_shutdown,
+	.settle = io_subchannel_settle,
+};
+
+int __init io_subchannel_init(void)
+{
+	int ret;
+
+	timer_setup(&recovery_timer, recovery_func, 0);
+	ret = bus_register(&ccw_bus_type);
+	if (ret)
+		return ret;
+	ret = css_driver_register(&io_subchannel_driver);
+	if (ret)
+		bus_unregister(&ccw_bus_type);
+
+	return ret;
+}
+
+
+/************************ device handling **************************/
+
+static ssize_t
+devtype_show (struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct ccw_device *cdev = to_ccwdev(dev);
+	struct ccw_device_id *id = &(cdev->id);
+
+	if (id->dev_type != 0)
+		return sprintf(buf, "%04x/%02x\n",
+				id->dev_type, id->dev_model);
+	else
+		return sprintf(buf, "n/a\n");
+}
+
+static ssize_t
+cutype_show (struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct ccw_device *cdev = to_ccwdev(dev);
+	struct ccw_device_id *id = &(cdev->id);
+
+	return sprintf(buf, "%04x/%02x\n",
+		       id->cu_type, id->cu_model);
+}
+
+static ssize_t
+modalias_show (struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct ccw_device *cdev = to_ccwdev(dev);
+	struct ccw_device_id *id = &(cdev->id);
+	int len;
+
+	len = snprint_alias(buf, PAGE_SIZE, id, "\n");
+
+	return len > PAGE_SIZE ? PAGE_SIZE : len;
+}
+
+static ssize_t
+online_show (struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct ccw_device *cdev = to_ccwdev(dev);
+
+	return sprintf(buf, cdev->online ? "1\n" : "0\n");
+}
+
+int ccw_device_is_orphan(struct ccw_device *cdev)
+{
+	return sch_is_pseudo_sch(to_subchannel(cdev->dev.parent));
+}
+
+static void ccw_device_unregister(struct ccw_device *cdev)
+{
+	mutex_lock(&cdev->reg_mutex);
+	if (device_is_registered(&cdev->dev)) {
+		/* Undo device_add(). */
+		device_del(&cdev->dev);
+	}
+	mutex_unlock(&cdev->reg_mutex);
+
+	if (cdev->private->flags.initialized) {
+		cdev->private->flags.initialized = 0;
+		/* Release reference from device_initialize(). */
+		put_device(&cdev->dev);
+	}
+}
+
+static void io_subchannel_quiesce(struct subchannel *);
+
+/**
+ * ccw_device_set_offline() - disable a ccw device for I/O
+ * @cdev: target ccw device
+ *
+ * This function calls the driver's set_offline() function for @cdev, if
+ * given, and then disables @cdev.
+ * Returns:
+ *   %0 on success and a negative error value on failure.
+ * Context:
+ *  enabled, ccw device lock not held
+ */
+int ccw_device_set_offline(struct ccw_device *cdev)
+{
+	struct subchannel *sch;
+	int ret, state;
+
+	if (!cdev)
+		return -ENODEV;
+	if (!cdev->online || !cdev->drv)
+		return -EINVAL;
+
+	if (cdev->drv->set_offline) {
+		ret = cdev->drv->set_offline(cdev);
+		if (ret != 0)
+			return ret;
+	}
+	spin_lock_irq(cdev->ccwlock);
+	sch = to_subchannel(cdev->dev.parent);
+	cdev->online = 0;
+	/* Wait until a final state or DISCONNECTED is reached */
+	while (!dev_fsm_final_state(cdev) &&
+	       cdev->private->state != DEV_STATE_DISCONNECTED) {
+		spin_unlock_irq(cdev->ccwlock);
+		wait_event(cdev->private->wait_q, (dev_fsm_final_state(cdev) ||
+			   cdev->private->state == DEV_STATE_DISCONNECTED));
+		spin_lock_irq(cdev->ccwlock);
+	}
+	do {
+		ret = ccw_device_offline(cdev);
+		if (!ret)
+			break;
+		CIO_MSG_EVENT(0, "ccw_device_offline returned %d, device "
+			      "0.%x.%04x\n", ret, cdev->private->dev_id.ssid,
+			      cdev->private->dev_id.devno);
+		if (ret != -EBUSY)
+			goto error;
+		state = cdev->private->state;
+		spin_unlock_irq(cdev->ccwlock);
+		io_subchannel_quiesce(sch);
+		spin_lock_irq(cdev->ccwlock);
+		cdev->private->state = state;
+	} while (ret == -EBUSY);
+	spin_unlock_irq(cdev->ccwlock);
+	wait_event(cdev->private->wait_q, (dev_fsm_final_state(cdev) ||
+		   cdev->private->state == DEV_STATE_DISCONNECTED));
+	/* Inform the user if set offline failed. */
+	if (cdev->private->state == DEV_STATE_BOXED) {
+		pr_warn("%s: The device entered boxed state while being set offline\n",
+			dev_name(&cdev->dev));
+	} else if (cdev->private->state == DEV_STATE_NOT_OPER) {
+		pr_warn("%s: The device stopped operating while being set offline\n",
+			dev_name(&cdev->dev));
+	}
+	/* Give up reference from ccw_device_set_online(). */
+	put_device(&cdev->dev);
+	return 0;
+
+error:
+	cdev->private->state = DEV_STATE_OFFLINE;
+	dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
+	spin_unlock_irq(cdev->ccwlock);
+	/* Give up reference from ccw_device_set_online(). */
+	put_device(&cdev->dev);
+	return -ENODEV;
+}
+
+/**
+ * ccw_device_set_online() - enable a ccw device for I/O
+ * @cdev: target ccw device
+ *
+ * This function first enables @cdev and then calls the driver's set_online()
+ * function for @cdev, if given. If set_online() returns an error, @cdev is
+ * disabled again.
+ * Returns:
+ *   %0 on success and a negative error value on failure.
+ * Context:
+ *  enabled, ccw device lock not held
+ */
+int ccw_device_set_online(struct ccw_device *cdev)
+{
+	int ret;
+	int ret2;
+
+	if (!cdev)
+		return -ENODEV;
+	if (cdev->online || !cdev->drv)
+		return -EINVAL;
+	/* Hold on to an extra reference while device is online. */
+	if (!get_device(&cdev->dev))
+		return -ENODEV;
+
+	spin_lock_irq(cdev->ccwlock);
+	ret = ccw_device_online(cdev);
+	spin_unlock_irq(cdev->ccwlock);
+	if (ret == 0)
+		wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev));
+	else {
+		CIO_MSG_EVENT(0, "ccw_device_online returned %d, "
+			      "device 0.%x.%04x\n",
+			      ret, cdev->private->dev_id.ssid,
+			      cdev->private->dev_id.devno);
+		/* Give up online reference since onlining failed. */
+		put_device(&cdev->dev);
+		return ret;
+	}
+	spin_lock_irq(cdev->ccwlock);
+	/* Check if online processing was successful */
+	if ((cdev->private->state != DEV_STATE_ONLINE) &&
+	    (cdev->private->state != DEV_STATE_W4SENSE)) {
+		spin_unlock_irq(cdev->ccwlock);
+		/* Inform the user that set online failed. */
+		if (cdev->private->state == DEV_STATE_BOXED) {
+			pr_warn("%s: Setting the device online failed because it is boxed\n",
+				dev_name(&cdev->dev));
+		} else if (cdev->private->state == DEV_STATE_NOT_OPER) {
+			pr_warn("%s: Setting the device online failed because it is not operational\n",
+				dev_name(&cdev->dev));
+		}
+		/* Give up online reference since onlining failed. */
+		put_device(&cdev->dev);
+		return -ENODEV;
+	}
+	spin_unlock_irq(cdev->ccwlock);
+	if (cdev->drv->set_online)
+		ret = cdev->drv->set_online(cdev);
+	if (ret)
+		goto rollback;
+
+	spin_lock_irq(cdev->ccwlock);
+	cdev->online = 1;
+	spin_unlock_irq(cdev->ccwlock);
+	return 0;
+
+rollback:
+	spin_lock_irq(cdev->ccwlock);
+	/* Wait until a final state or DISCONNECTED is reached */
+	while (!dev_fsm_final_state(cdev) &&
+	       cdev->private->state != DEV_STATE_DISCONNECTED) {
+		spin_unlock_irq(cdev->ccwlock);
+		wait_event(cdev->private->wait_q, (dev_fsm_final_state(cdev) ||
+			   cdev->private->state == DEV_STATE_DISCONNECTED));
+		spin_lock_irq(cdev->ccwlock);
+	}
+	ret2 = ccw_device_offline(cdev);
+	if (ret2)
+		goto error;
+	spin_unlock_irq(cdev->ccwlock);
+	wait_event(cdev->private->wait_q, (dev_fsm_final_state(cdev) ||
+		   cdev->private->state == DEV_STATE_DISCONNECTED));
+	/* Give up online reference since onlining failed. */
+	put_device(&cdev->dev);
+	return ret;
+
+error:
+	CIO_MSG_EVENT(0, "rollback ccw_device_offline returned %d, "
+		      "device 0.%x.%04x\n",
+		      ret2, cdev->private->dev_id.ssid,
+		      cdev->private->dev_id.devno);
+	cdev->private->state = DEV_STATE_OFFLINE;
+	spin_unlock_irq(cdev->ccwlock);
+	/* Give up online reference since onlining failed. */
+	put_device(&cdev->dev);
+	return ret;
+}
+
+static int online_store_handle_offline(struct ccw_device *cdev)
+{
+	if (cdev->private->state == DEV_STATE_DISCONNECTED) {
+		spin_lock_irq(cdev->ccwlock);
+		ccw_device_sched_todo(cdev, CDEV_TODO_UNREG_EVAL);
+		spin_unlock_irq(cdev->ccwlock);
+		return 0;
+	}
+	if (cdev->drv && cdev->drv->set_offline)
+		return ccw_device_set_offline(cdev);
+	return -EINVAL;
+}
+
+static int online_store_recog_and_online(struct ccw_device *cdev)
+{
+	/* Do device recognition, if needed. */
+	if (cdev->private->state == DEV_STATE_BOXED) {
+		spin_lock_irq(cdev->ccwlock);
+		ccw_device_recognition(cdev);
+		spin_unlock_irq(cdev->ccwlock);
+		wait_event(cdev->private->wait_q,
+			   cdev->private->flags.recog_done);
+		if (cdev->private->state != DEV_STATE_OFFLINE)
+			/* recognition failed */
+			return -EAGAIN;
+	}
+	if (cdev->drv && cdev->drv->set_online)
+		return ccw_device_set_online(cdev);
+	return -EINVAL;
+}
+
+static int online_store_handle_online(struct ccw_device *cdev, int force)
+{
+	int ret;
+
+	ret = online_store_recog_and_online(cdev);
+	if (ret && !force)
+		return ret;
+	if (force && cdev->private->state == DEV_STATE_BOXED) {
+		ret = ccw_device_stlck(cdev);
+		if (ret)
+			return ret;
+		if (cdev->id.cu_type == 0)
+			cdev->private->state = DEV_STATE_NOT_OPER;
+		ret = online_store_recog_and_online(cdev);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+static ssize_t online_store (struct device *dev, struct device_attribute *attr,
+			     const char *buf, size_t count)
+{
+	struct ccw_device *cdev = to_ccwdev(dev);
+	int force, ret;
+	unsigned long i;
+
+	/* Prevent conflict between multiple on-/offline processing requests. */
+	if (atomic_cmpxchg(&cdev->private->onoff, 0, 1) != 0)
+		return -EAGAIN;
+	/* Prevent conflict between internal I/Os and on-/offline processing. */
+	if (!dev_fsm_final_state(cdev) &&
+	    cdev->private->state != DEV_STATE_DISCONNECTED) {
+		ret = -EAGAIN;
+		goto out;
+	}
+	/* Prevent conflict between pending work and on-/offline processing.*/
+	if (work_pending(&cdev->private->todo_work)) {
+		ret = -EAGAIN;
+		goto out;
+	}
+	if (!strncmp(buf, "force\n", count)) {
+		force = 1;
+		i = 1;
+		ret = 0;
+	} else {
+		force = 0;
+		ret = kstrtoul(buf, 16, &i);
+	}
+	if (ret)
+		goto out;
+
+	device_lock(dev);
+	switch (i) {
+	case 0:
+		ret = online_store_handle_offline(cdev);
+		break;
+	case 1:
+		ret = online_store_handle_online(cdev, force);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+	device_unlock(dev);
+
+out:
+	atomic_set(&cdev->private->onoff, 0);
+	return (ret < 0) ? ret : count;
+}
+
+static ssize_t
+available_show (struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct ccw_device *cdev = to_ccwdev(dev);
+	struct subchannel *sch;
+
+	if (ccw_device_is_orphan(cdev))
+		return sprintf(buf, "no device\n");
+	switch (cdev->private->state) {
+	case DEV_STATE_BOXED:
+		return sprintf(buf, "boxed\n");
+	case DEV_STATE_DISCONNECTED:
+	case DEV_STATE_DISCONNECTED_SENSE_ID:
+	case DEV_STATE_NOT_OPER:
+		sch = to_subchannel(dev->parent);
+		if (!sch->lpm)
+			return sprintf(buf, "no path\n");
+		else
+			return sprintf(buf, "no device\n");
+	default:
+		/* All other states considered fine. */
+		return sprintf(buf, "good\n");
+	}
+}
+
+static ssize_t
+initiate_logging(struct device *dev, struct device_attribute *attr,
+		 const char *buf, size_t count)
+{
+	struct subchannel *sch = to_subchannel(dev);
+	int rc;
+
+	rc = chsc_siosl(sch->schid);
+	if (rc < 0) {
+		pr_warn("Logging for subchannel 0.%x.%04x failed with errno=%d\n",
+			sch->schid.ssid, sch->schid.sch_no, rc);
+		return rc;
+	}
+	pr_notice("Logging for subchannel 0.%x.%04x was triggered\n",
+		  sch->schid.ssid, sch->schid.sch_no);
+	return count;
+}
+
+static ssize_t vpm_show(struct device *dev, struct device_attribute *attr,
+			char *buf)
+{
+	struct subchannel *sch = to_subchannel(dev);
+
+	return sprintf(buf, "%02x\n", sch->vpm);
+}
+
+static DEVICE_ATTR_RO(devtype);
+static DEVICE_ATTR_RO(cutype);
+static DEVICE_ATTR_RO(modalias);
+static DEVICE_ATTR_RW(online);
+static DEVICE_ATTR(availability, 0444, available_show, NULL);
+static DEVICE_ATTR(logging, 0200, NULL, initiate_logging);
+static DEVICE_ATTR_RO(vpm);
+
+static struct attribute *io_subchannel_attrs[] = {
+	&dev_attr_logging.attr,
+	&dev_attr_vpm.attr,
+	NULL,
+};
+
+static const struct attribute_group io_subchannel_attr_group = {
+	.attrs = io_subchannel_attrs,
+};
+
+static struct attribute * ccwdev_attrs[] = {
+	&dev_attr_devtype.attr,
+	&dev_attr_cutype.attr,
+	&dev_attr_modalias.attr,
+	&dev_attr_online.attr,
+	&dev_attr_cmb_enable.attr,
+	&dev_attr_availability.attr,
+	NULL,
+};
+
+static const struct attribute_group ccwdev_attr_group = {
+	.attrs = ccwdev_attrs,
+};
+
+static const struct attribute_group *ccwdev_attr_groups[] = {
+	&ccwdev_attr_group,
+	NULL,
+};
+
+static int match_dev_id(struct device *dev, const void *data)
+{
+	struct ccw_device *cdev = to_ccwdev(dev);
+	struct ccw_dev_id *dev_id = (void *)data;
+
+	return ccw_dev_id_is_equal(&cdev->private->dev_id, dev_id);
+}
+
+/**
+ * get_ccwdev_by_dev_id() - obtain device from a ccw device id
+ * @dev_id: id of the device to be searched
+ *
+ * This function searches all devices attached to the ccw bus for a device
+ * matching @dev_id.
+ * Returns:
+ *  If a device is found its reference count is increased and returned;
+ *  else %NULL is returned.
+ */
+struct ccw_device *get_ccwdev_by_dev_id(struct ccw_dev_id *dev_id)
+{
+	struct device *dev;
+
+	dev = bus_find_device(&ccw_bus_type, NULL, dev_id, match_dev_id);
+
+	return dev ? to_ccwdev(dev) : NULL;
+}
+EXPORT_SYMBOL_GPL(get_ccwdev_by_dev_id);
+
+static void ccw_device_do_unbind_bind(struct ccw_device *cdev)
+{
+	int ret;
+
+	mutex_lock(&cdev->reg_mutex);
+	if (device_is_registered(&cdev->dev)) {
+		device_release_driver(&cdev->dev);
+		ret = device_attach(&cdev->dev);
+		WARN_ON(ret == -ENODEV);
+	}
+	mutex_unlock(&cdev->reg_mutex);
+}
+
+static void
+ccw_device_release(struct device *dev)
+{
+	struct ccw_device *cdev;
+
+	cdev = to_ccwdev(dev);
+	cio_gp_dma_free(cdev->private->dma_pool, cdev->private->dma_area,
+			sizeof(*cdev->private->dma_area));
+	cio_gp_dma_destroy(cdev->private->dma_pool, &cdev->dev);
+	/* Release reference of parent subchannel. */
+	put_device(cdev->dev.parent);
+	kfree(cdev->private);
+	kfree(cdev);
+}
+
+static struct ccw_device * io_subchannel_allocate_dev(struct subchannel *sch)
+{
+	struct ccw_device *cdev;
+	struct gen_pool *dma_pool;
+	int ret;
+
+	cdev  = kzalloc(sizeof(*cdev), GFP_KERNEL);
+	if (!cdev) {
+		ret = -ENOMEM;
+		goto err_cdev;
+	}
+	cdev->private = kzalloc(sizeof(struct ccw_device_private),
+				GFP_KERNEL | GFP_DMA);
+	if (!cdev->private) {
+		ret = -ENOMEM;
+		goto err_priv;
+	}
+
+	cdev->dev.dma_mask = sch->dev.dma_mask;
+	ret = dma_set_coherent_mask(&cdev->dev, sch->dev.coherent_dma_mask);
+	if (ret)
+		goto err_coherent_mask;
+
+	dma_pool = cio_gp_dma_create(&cdev->dev, 1);
+	if (!dma_pool) {
+		ret = -ENOMEM;
+		goto err_dma_pool;
+	}
+	cdev->private->dma_pool = dma_pool;
+	cdev->private->dma_area = cio_gp_dma_zalloc(dma_pool, &cdev->dev,
+					sizeof(*cdev->private->dma_area));
+	if (!cdev->private->dma_area) {
+		ret = -ENOMEM;
+		goto err_dma_area;
+	}
+	return cdev;
+err_dma_area:
+	cio_gp_dma_destroy(dma_pool, &cdev->dev);
+err_dma_pool:
+err_coherent_mask:
+	kfree(cdev->private);
+err_priv:
+	kfree(cdev);
+err_cdev:
+	return ERR_PTR(ret);
+}
+
+static void ccw_device_todo(struct work_struct *work);
+
+static int io_subchannel_initialize_dev(struct subchannel *sch,
+					struct ccw_device *cdev)
+{
+	struct ccw_device_private *priv = cdev->private;
+	int ret;
+
+	priv->cdev = cdev;
+	priv->int_class = IRQIO_CIO;
+	priv->state = DEV_STATE_NOT_OPER;
+	priv->dev_id.devno = sch->schib.pmcw.dev;
+	priv->dev_id.ssid = sch->schid.ssid;
+
+	INIT_WORK(&priv->todo_work, ccw_device_todo);
+	INIT_LIST_HEAD(&priv->cmb_list);
+	init_waitqueue_head(&priv->wait_q);
+	timer_setup(&priv->timer, ccw_device_timeout, 0);
+	mutex_init(&cdev->reg_mutex);
+
+	atomic_set(&priv->onoff, 0);
+	cdev->ccwlock = sch->lock;
+	cdev->dev.parent = &sch->dev;
+	cdev->dev.release = ccw_device_release;
+	cdev->dev.bus = &ccw_bus_type;
+	cdev->dev.groups = ccwdev_attr_groups;
+	/* Do first half of device_register. */
+	device_initialize(&cdev->dev);
+	ret = dev_set_name(&cdev->dev, "0.%x.%04x", cdev->private->dev_id.ssid,
+			   cdev->private->dev_id.devno);
+	if (ret)
+		goto out_put;
+	if (!get_device(&sch->dev)) {
+		ret = -ENODEV;
+		goto out_put;
+	}
+	priv->flags.initialized = 1;
+	spin_lock_irq(sch->lock);
+	sch_set_cdev(sch, cdev);
+	spin_unlock_irq(sch->lock);
+	return 0;
+
+out_put:
+	/* Release reference from device_initialize(). */
+	put_device(&cdev->dev);
+	return ret;
+}
+
+static struct ccw_device * io_subchannel_create_ccwdev(struct subchannel *sch)
+{
+	struct ccw_device *cdev;
+	int ret;
+
+	cdev = io_subchannel_allocate_dev(sch);
+	if (!IS_ERR(cdev)) {
+		ret = io_subchannel_initialize_dev(sch, cdev);
+		if (ret)
+			cdev = ERR_PTR(ret);
+	}
+	return cdev;
+}
+
+static void io_subchannel_recog(struct ccw_device *, struct subchannel *);
+
+static void sch_create_and_recog_new_device(struct subchannel *sch)
+{
+	struct ccw_device *cdev;
+
+	/* Need to allocate a new ccw device. */
+	cdev = io_subchannel_create_ccwdev(sch);
+	if (IS_ERR(cdev)) {
+		/* OK, we did everything we could... */
+		css_sch_device_unregister(sch);
+		return;
+	}
+	/* Start recognition for the new ccw device. */
+	io_subchannel_recog(cdev, sch);
+}
+
+/*
+ * Register recognized device.
+ */
+static void io_subchannel_register(struct ccw_device *cdev)
+{
+	struct subchannel *sch;
+	int ret, adjust_init_count = 1;
+	unsigned long flags;
+
+	sch = to_subchannel(cdev->dev.parent);
+	/*
+	 * Check if subchannel is still registered. It may have become
+	 * unregistered if a machine check hit us after finishing
+	 * device recognition but before the register work could be
+	 * queued.
+	 */
+	if (!device_is_registered(&sch->dev))
+		goto out_err;
+	css_update_ssd_info(sch);
+	/*
+	 * io_subchannel_register() will also be called after device
+	 * recognition has been done for a boxed device (which will already
+	 * be registered). We need to reprobe since we may now have sense id
+	 * information.
+	 */
+	mutex_lock(&cdev->reg_mutex);
+	if (device_is_registered(&cdev->dev)) {
+		if (!cdev->drv) {
+			ret = device_reprobe(&cdev->dev);
+			if (ret)
+				/* We can't do much here. */
+				CIO_MSG_EVENT(0, "device_reprobe() returned"
+					      " %d for 0.%x.%04x\n", ret,
+					      cdev->private->dev_id.ssid,
+					      cdev->private->dev_id.devno);
+		}
+		adjust_init_count = 0;
+		goto out;
+	}
+	/* make it known to the system */
+	ret = device_add(&cdev->dev);
+	if (ret) {
+		CIO_MSG_EVENT(0, "Could not register ccw dev 0.%x.%04x: %d\n",
+			      cdev->private->dev_id.ssid,
+			      cdev->private->dev_id.devno, ret);
+		spin_lock_irqsave(sch->lock, flags);
+		sch_set_cdev(sch, NULL);
+		spin_unlock_irqrestore(sch->lock, flags);
+		mutex_unlock(&cdev->reg_mutex);
+		/* Release initial device reference. */
+		put_device(&cdev->dev);
+		goto out_err;
+	}
+out:
+	cdev->private->flags.recog_done = 1;
+	mutex_unlock(&cdev->reg_mutex);
+	wake_up(&cdev->private->wait_q);
+out_err:
+	if (adjust_init_count && atomic_dec_and_test(&ccw_device_init_count))
+		wake_up(&ccw_device_init_wq);
+}
+
+/*
+ * subchannel recognition done. Called from the state machine.
+ */
+void
+io_subchannel_recog_done(struct ccw_device *cdev)
+{
+	if (css_init_done == 0) {
+		cdev->private->flags.recog_done = 1;
+		return;
+	}
+	switch (cdev->private->state) {
+	case DEV_STATE_BOXED:
+		/* Device did not respond in time. */
+	case DEV_STATE_NOT_OPER:
+		cdev->private->flags.recog_done = 1;
+		/* Remove device found not operational. */
+		ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
+		if (atomic_dec_and_test(&ccw_device_init_count))
+			wake_up(&ccw_device_init_wq);
+		break;
+	case DEV_STATE_OFFLINE:
+		/*
+		 * We can't register the device in interrupt context so
+		 * we schedule a work item.
+		 */
+		ccw_device_sched_todo(cdev, CDEV_TODO_REGISTER);
+		break;
+	}
+}
+
+static void io_subchannel_recog(struct ccw_device *cdev, struct subchannel *sch)
+{
+	/* Increase counter of devices currently in recognition. */
+	atomic_inc(&ccw_device_init_count);
+
+	/* Start async. device sensing. */
+	spin_lock_irq(sch->lock);
+	ccw_device_recognition(cdev);
+	spin_unlock_irq(sch->lock);
+}
+
+static int ccw_device_move_to_sch(struct ccw_device *cdev,
+				  struct subchannel *sch)
+{
+	struct subchannel *old_sch;
+	int rc, old_enabled = 0;
+
+	old_sch = to_subchannel(cdev->dev.parent);
+	/* Obtain child reference for new parent. */
+	if (!get_device(&sch->dev))
+		return -ENODEV;
+
+	if (!sch_is_pseudo_sch(old_sch)) {
+		spin_lock_irq(old_sch->lock);
+		old_enabled = old_sch->schib.pmcw.ena;
+		rc = 0;
+		if (old_enabled)
+			rc = cio_disable_subchannel(old_sch);
+		spin_unlock_irq(old_sch->lock);
+		if (rc == -EBUSY) {
+			/* Release child reference for new parent. */
+			put_device(&sch->dev);
+			return rc;
+		}
+	}
+
+	mutex_lock(&sch->reg_mutex);
+	rc = device_move(&cdev->dev, &sch->dev, DPM_ORDER_PARENT_BEFORE_DEV);
+	mutex_unlock(&sch->reg_mutex);
+	if (rc) {
+		CIO_MSG_EVENT(0, "device_move(0.%x.%04x,0.%x.%04x)=%d\n",
+			      cdev->private->dev_id.ssid,
+			      cdev->private->dev_id.devno, sch->schid.ssid,
+			      sch->schib.pmcw.dev, rc);
+		if (old_enabled) {
+			/* Try to re-enable the old subchannel. */
+			spin_lock_irq(old_sch->lock);
+			cio_enable_subchannel(old_sch, (u32)virt_to_phys(old_sch));
+			spin_unlock_irq(old_sch->lock);
+		}
+		/* Release child reference for new parent. */
+		put_device(&sch->dev);
+		return rc;
+	}
+	/* Clean up old subchannel. */
+	if (!sch_is_pseudo_sch(old_sch)) {
+		spin_lock_irq(old_sch->lock);
+		sch_set_cdev(old_sch, NULL);
+		spin_unlock_irq(old_sch->lock);
+		css_schedule_eval(old_sch->schid);
+	}
+	/* Release child reference for old parent. */
+	put_device(&old_sch->dev);
+	/* Initialize new subchannel. */
+	spin_lock_irq(sch->lock);
+	cdev->ccwlock = sch->lock;
+	if (!sch_is_pseudo_sch(sch))
+		sch_set_cdev(sch, cdev);
+	spin_unlock_irq(sch->lock);
+	if (!sch_is_pseudo_sch(sch))
+		css_update_ssd_info(sch);
+	return 0;
+}
+
+static int ccw_device_move_to_orph(struct ccw_device *cdev)
+{
+	struct subchannel *sch = to_subchannel(cdev->dev.parent);
+	struct channel_subsystem *css = to_css(sch->dev.parent);
+
+	return ccw_device_move_to_sch(cdev, css->pseudo_subchannel);
+}
+
+static void io_subchannel_irq(struct subchannel *sch)
+{
+	struct ccw_device *cdev;
+
+	cdev = sch_get_cdev(sch);
+
+	CIO_TRACE_EVENT(6, "IRQ");
+	CIO_TRACE_EVENT(6, dev_name(&sch->dev));
+	if (cdev)
+		dev_fsm_event(cdev, DEV_EVENT_INTERRUPT);
+	else
+		inc_irq_stat(IRQIO_CIO);
+}
+
+void io_subchannel_init_config(struct subchannel *sch)
+{
+	memset(&sch->config, 0, sizeof(sch->config));
+	sch->config.csense = 1;
+}
+
+static void io_subchannel_init_fields(struct subchannel *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;
+	sch->isc = cio_is_console(sch->schid) ? CONSOLE_ISC : IO_SCH_ISC;
+
+	CIO_MSG_EVENT(6, "Detected device %04x on subchannel 0.%x.%04X"
+		      " - PIM = %02X, PAM = %02X, POM = %02X\n",
+		      sch->schib.pmcw.dev, sch->schid.ssid,
+		      sch->schid.sch_no, sch->schib.pmcw.pim,
+		      sch->schib.pmcw.pam, sch->schib.pmcw.pom);
+
+	io_subchannel_init_config(sch);
+}
+
+/*
+ * Note: We always return 0 so that we bind to the device even on error.
+ * This is needed so that our remove function is called on unregister.
+ */
+static int io_subchannel_probe(struct subchannel *sch)
+{
+	struct io_subchannel_private *io_priv;
+	struct ccw_device *cdev;
+	int rc;
+
+	if (cio_is_console(sch->schid)) {
+		rc = sysfs_create_group(&sch->dev.kobj,
+					&io_subchannel_attr_group);
+		if (rc)
+			CIO_MSG_EVENT(0, "Failed to create io subchannel "
+				      "attributes for subchannel "
+				      "0.%x.%04x (rc=%d)\n",
+				      sch->schid.ssid, sch->schid.sch_no, rc);
+		/*
+		* The console subchannel already has an associated ccw_device.
+		* Register it and exit.
+		*/
+		cdev = sch_get_cdev(sch);
+		rc = device_add(&cdev->dev);
+		if (rc) {
+			/* Release online reference. */
+			put_device(&cdev->dev);
+			goto out_schedule;
+		}
+		if (atomic_dec_and_test(&ccw_device_init_count))
+			wake_up(&ccw_device_init_wq);
+		return 0;
+	}
+	io_subchannel_init_fields(sch);
+	rc = cio_commit_config(sch);
+	if (rc)
+		goto out_schedule;
+	rc = sysfs_create_group(&sch->dev.kobj,
+				&io_subchannel_attr_group);
+	if (rc)
+		goto out_schedule;
+	/* Allocate I/O subchannel private data. */
+	io_priv = kzalloc(sizeof(*io_priv), GFP_KERNEL | GFP_DMA);
+	if (!io_priv)
+		goto out_schedule;
+
+	io_priv->dma_area = dma_alloc_coherent(&sch->dev,
+				sizeof(*io_priv->dma_area),
+				&io_priv->dma_area_dma, GFP_KERNEL);
+	if (!io_priv->dma_area) {
+		kfree(io_priv);
+		goto out_schedule;
+	}
+
+	set_io_private(sch, io_priv);
+	css_schedule_eval(sch->schid);
+	return 0;
+
+out_schedule:
+	spin_lock_irq(sch->lock);
+	css_sched_sch_todo(sch, SCH_TODO_UNREG);
+	spin_unlock_irq(sch->lock);
+	return 0;
+}
+
+static void io_subchannel_remove(struct subchannel *sch)
+{
+	struct io_subchannel_private *io_priv = to_io_private(sch);
+	struct ccw_device *cdev;
+
+	cdev = sch_get_cdev(sch);
+	if (!cdev)
+		goto out_free;
+
+	ccw_device_unregister(cdev);
+	spin_lock_irq(sch->lock);
+	sch_set_cdev(sch, NULL);
+	set_io_private(sch, NULL);
+	spin_unlock_irq(sch->lock);
+out_free:
+	dma_free_coherent(&sch->dev, sizeof(*io_priv->dma_area),
+			  io_priv->dma_area, io_priv->dma_area_dma);
+	kfree(io_priv);
+	sysfs_remove_group(&sch->dev.kobj, &io_subchannel_attr_group);
+}
+
+static void io_subchannel_verify(struct subchannel *sch)
+{
+	struct ccw_device *cdev;
+
+	cdev = sch_get_cdev(sch);
+	if (cdev)
+		dev_fsm_event(cdev, DEV_EVENT_VERIFY);
+	else
+		css_schedule_eval(sch->schid);
+}
+
+static void io_subchannel_terminate_path(struct subchannel *sch, u8 mask)
+{
+	struct ccw_device *cdev;
+
+	cdev = sch_get_cdev(sch);
+	if (!cdev)
+		return;
+	if (cio_update_schib(sch))
+		goto err;
+	/* Check for I/O on path. */
+	if (scsw_actl(&sch->schib.scsw) == 0 || sch->schib.pmcw.lpum != mask)
+		goto out;
+	if (cdev->private->state == DEV_STATE_ONLINE) {
+		ccw_device_kill_io(cdev);
+		goto out;
+	}
+	if (cio_clear(sch))
+		goto err;
+out:
+	/* Trigger path verification. */
+	dev_fsm_event(cdev, DEV_EVENT_VERIFY);
+	return;
+
+err:
+	dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
+}
+
+static int io_subchannel_chp_event(struct subchannel *sch,
+				   struct chp_link *link, int event)
+{
+	struct ccw_device *cdev = sch_get_cdev(sch);
+	int mask, chpid, valid_bit;
+	int path_event[8];
+
+	mask = chp_ssd_get_mask(&sch->ssd_info, link);
+	if (!mask)
+		return 0;
+	switch (event) {
+	case CHP_VARY_OFF:
+		sch->opm &= ~mask;
+		sch->lpm &= ~mask;
+		if (cdev)
+			cdev->private->path_gone_mask |= mask;
+		io_subchannel_terminate_path(sch, mask);
+		break;
+	case CHP_VARY_ON:
+		sch->opm |= mask;
+		sch->lpm |= mask;
+		if (cdev)
+			cdev->private->path_new_mask |= mask;
+		io_subchannel_verify(sch);
+		break;
+	case CHP_OFFLINE:
+		if (cio_update_schib(sch))
+			return -ENODEV;
+		if (cdev)
+			cdev->private->path_gone_mask |= mask;
+		io_subchannel_terminate_path(sch, mask);
+		break;
+	case CHP_ONLINE:
+		if (cio_update_schib(sch))
+			return -ENODEV;
+		sch->lpm |= mask & sch->opm;
+		if (cdev)
+			cdev->private->path_new_mask |= mask;
+		io_subchannel_verify(sch);
+		break;
+	case CHP_FCES_EVENT:
+		/* Forward Endpoint Security event */
+		for (chpid = 0, valid_bit = 0x80; chpid < 8; chpid++,
+				valid_bit >>= 1) {
+			if (mask & valid_bit)
+				path_event[chpid] = PE_PATH_FCES_EVENT;
+			else
+				path_event[chpid] = PE_NONE;
+		}
+		if (cdev && cdev->drv && cdev->drv->path_event)
+			cdev->drv->path_event(cdev, path_event);
+		break;
+	}
+	return 0;
+}
+
+static void io_subchannel_quiesce(struct subchannel *sch)
+{
+	struct ccw_device *cdev;
+	int ret;
+
+	spin_lock_irq(sch->lock);
+	cdev = sch_get_cdev(sch);
+	if (cio_is_console(sch->schid))
+		goto out_unlock;
+	if (!sch->schib.pmcw.ena)
+		goto out_unlock;
+	ret = cio_disable_subchannel(sch);
+	if (ret != -EBUSY)
+		goto out_unlock;
+	if (cdev->handler)
+		cdev->handler(cdev, cdev->private->intparm, ERR_PTR(-EIO));
+	while (ret == -EBUSY) {
+		cdev->private->state = DEV_STATE_QUIESCE;
+		cdev->private->iretry = 255;
+		ret = ccw_device_cancel_halt_clear(cdev);
+		if (ret == -EBUSY) {
+			ccw_device_set_timeout(cdev, HZ/10);
+			spin_unlock_irq(sch->lock);
+			wait_event(cdev->private->wait_q,
+				   cdev->private->state != DEV_STATE_QUIESCE);
+			spin_lock_irq(sch->lock);
+		}
+		ret = cio_disable_subchannel(sch);
+	}
+out_unlock:
+	spin_unlock_irq(sch->lock);
+}
+
+static void io_subchannel_shutdown(struct subchannel *sch)
+{
+	io_subchannel_quiesce(sch);
+}
+
+static int device_is_disconnected(struct ccw_device *cdev)
+{
+	if (!cdev)
+		return 0;
+	return (cdev->private->state == DEV_STATE_DISCONNECTED ||
+		cdev->private->state == DEV_STATE_DISCONNECTED_SENSE_ID);
+}
+
+static int recovery_check(struct device *dev, void *data)
+{
+	struct ccw_device *cdev = to_ccwdev(dev);
+	struct subchannel *sch;
+	int *redo = data;
+
+	spin_lock_irq(cdev->ccwlock);
+	switch (cdev->private->state) {
+	case DEV_STATE_ONLINE:
+		sch = to_subchannel(cdev->dev.parent);
+		if ((sch->schib.pmcw.pam & sch->opm) == sch->vpm)
+			break;
+		fallthrough;
+	case DEV_STATE_DISCONNECTED:
+		CIO_MSG_EVENT(3, "recovery: trigger 0.%x.%04x\n",
+			      cdev->private->dev_id.ssid,
+			      cdev->private->dev_id.devno);
+		dev_fsm_event(cdev, DEV_EVENT_VERIFY);
+		*redo = 1;
+		break;
+	case DEV_STATE_DISCONNECTED_SENSE_ID:
+		*redo = 1;
+		break;
+	}
+	spin_unlock_irq(cdev->ccwlock);
+
+	return 0;
+}
+
+static void recovery_work_func(struct work_struct *unused)
+{
+	int redo = 0;
+
+	bus_for_each_dev(&ccw_bus_type, NULL, &redo, recovery_check);
+	if (redo) {
+		spin_lock_irq(&recovery_lock);
+		if (!timer_pending(&recovery_timer)) {
+			if (recovery_phase < ARRAY_SIZE(recovery_delay) - 1)
+				recovery_phase++;
+			mod_timer(&recovery_timer, jiffies +
+				  recovery_delay[recovery_phase] * HZ);
+		}
+		spin_unlock_irq(&recovery_lock);
+	} else
+		CIO_MSG_EVENT(3, "recovery: end\n");
+}
+
+static DECLARE_WORK(recovery_work, recovery_work_func);
+
+static void recovery_func(struct timer_list *unused)
+{
+	/*
+	 * We can't do our recovery in softirq context and it's not
+	 * performance critical, so we schedule it.
+	 */
+	schedule_work(&recovery_work);
+}
+
+void ccw_device_schedule_recovery(void)
+{
+	unsigned long flags;
+
+	CIO_MSG_EVENT(3, "recovery: schedule\n");
+	spin_lock_irqsave(&recovery_lock, flags);
+	if (!timer_pending(&recovery_timer) || (recovery_phase != 0)) {
+		recovery_phase = 0;
+		mod_timer(&recovery_timer, jiffies + recovery_delay[0] * HZ);
+	}
+	spin_unlock_irqrestore(&recovery_lock, flags);
+}
+
+static int purge_fn(struct device *dev, void *data)
+{
+	struct ccw_device *cdev = to_ccwdev(dev);
+	struct ccw_dev_id *id = &cdev->private->dev_id;
+	struct subchannel *sch = to_subchannel(cdev->dev.parent);
+
+	spin_lock_irq(cdev->ccwlock);
+	if (is_blacklisted(id->ssid, id->devno) &&
+	    (cdev->private->state == DEV_STATE_OFFLINE) &&
+	    (atomic_cmpxchg(&cdev->private->onoff, 0, 1) == 0)) {
+		CIO_MSG_EVENT(3, "ccw: purging 0.%x.%04x\n", id->ssid,
+			      id->devno);
+		ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
+		css_sched_sch_todo(sch, SCH_TODO_UNREG);
+		atomic_set(&cdev->private->onoff, 0);
+	}
+	spin_unlock_irq(cdev->ccwlock);
+	/* Abort loop in case of pending signal. */
+	if (signal_pending(current))
+		return -EINTR;
+
+	return 0;
+}
+
+/**
+ * ccw_purge_blacklisted - purge unused, blacklisted devices
+ *
+ * Unregister all ccw devices that are offline and on the blacklist.
+ */
+int ccw_purge_blacklisted(void)
+{
+	CIO_MSG_EVENT(2, "ccw: purging blacklisted devices\n");
+	bus_for_each_dev(&ccw_bus_type, NULL, NULL, purge_fn);
+	return 0;
+}
+
+void ccw_device_set_disconnected(struct ccw_device *cdev)
+{
+	if (!cdev)
+		return;
+	ccw_device_set_timeout(cdev, 0);
+	cdev->private->flags.fake_irb = 0;
+	cdev->private->state = DEV_STATE_DISCONNECTED;
+	if (cdev->online)
+		ccw_device_schedule_recovery();
+}
+
+void ccw_device_set_notoper(struct ccw_device *cdev)
+{
+	struct subchannel *sch = to_subchannel(cdev->dev.parent);
+
+	CIO_TRACE_EVENT(2, "notoper");
+	CIO_TRACE_EVENT(2, dev_name(&sch->dev));
+	ccw_device_set_timeout(cdev, 0);
+	cio_disable_subchannel(sch);
+	cdev->private->state = DEV_STATE_NOT_OPER;
+}
+
+enum io_sch_action {
+	IO_SCH_UNREG,
+	IO_SCH_ORPH_UNREG,
+	IO_SCH_UNREG_CDEV,
+	IO_SCH_ATTACH,
+	IO_SCH_UNREG_ATTACH,
+	IO_SCH_ORPH_ATTACH,
+	IO_SCH_REPROBE,
+	IO_SCH_VERIFY,
+	IO_SCH_DISC,
+	IO_SCH_NOP,
+};
+
+static enum io_sch_action sch_get_action(struct subchannel *sch)
+{
+	struct ccw_device *cdev;
+
+	cdev = sch_get_cdev(sch);
+	if (cio_update_schib(sch)) {
+		/* Not operational. */
+		if (!cdev)
+			return IO_SCH_UNREG;
+		if (ccw_device_notify(cdev, CIO_GONE) != NOTIFY_OK)
+			return IO_SCH_UNREG;
+		return IO_SCH_ORPH_UNREG;
+	}
+	/* Operational. */
+	if (!cdev)
+		return IO_SCH_ATTACH;
+	if (sch->schib.pmcw.dev != cdev->private->dev_id.devno) {
+		if (ccw_device_notify(cdev, CIO_GONE) != NOTIFY_OK)
+			return IO_SCH_UNREG_ATTACH;
+		return IO_SCH_ORPH_ATTACH;
+	}
+	if ((sch->schib.pmcw.pam & sch->opm) == 0) {
+		if (ccw_device_notify(cdev, CIO_NO_PATH) != NOTIFY_OK)
+			return IO_SCH_UNREG_CDEV;
+		return IO_SCH_DISC;
+	}
+	if (device_is_disconnected(cdev))
+		return IO_SCH_REPROBE;
+	if (cdev->online)
+		return IO_SCH_VERIFY;
+	if (cdev->private->state == DEV_STATE_NOT_OPER)
+		return IO_SCH_UNREG_ATTACH;
+	return IO_SCH_NOP;
+}
+
+/**
+ * io_subchannel_sch_event - process subchannel event
+ * @sch: subchannel
+ * @process: non-zero if function is called in process context
+ *
+ * An unspecified event occurred for this subchannel. Adjust data according
+ * to the current operational state of the subchannel and device. Return
+ * zero when the event has been handled sufficiently or -EAGAIN when this
+ * function should be called again in process context.
+ */
+static int io_subchannel_sch_event(struct subchannel *sch, int process)
+{
+	unsigned long flags;
+	struct ccw_device *cdev;
+	struct ccw_dev_id dev_id;
+	enum io_sch_action action;
+	int rc = -EAGAIN;
+
+	spin_lock_irqsave(sch->lock, flags);
+	if (!device_is_registered(&sch->dev))
+		goto out_unlock;
+	if (work_pending(&sch->todo_work))
+		goto out_unlock;
+	cdev = sch_get_cdev(sch);
+	if (cdev && work_pending(&cdev->private->todo_work))
+		goto out_unlock;
+	action = sch_get_action(sch);
+	CIO_MSG_EVENT(2, "event: sch 0.%x.%04x, process=%d, action=%d\n",
+		      sch->schid.ssid, sch->schid.sch_no, process,
+		      action);
+	/* Perform immediate actions while holding the lock. */
+	switch (action) {
+	case IO_SCH_REPROBE:
+		/* Trigger device recognition. */
+		ccw_device_trigger_reprobe(cdev);
+		rc = 0;
+		goto out_unlock;
+	case IO_SCH_VERIFY:
+		/* Trigger path verification. */
+		io_subchannel_verify(sch);
+		rc = 0;
+		goto out_unlock;
+	case IO_SCH_DISC:
+		ccw_device_set_disconnected(cdev);
+		rc = 0;
+		goto out_unlock;
+	case IO_SCH_ORPH_UNREG:
+	case IO_SCH_ORPH_ATTACH:
+		ccw_device_set_disconnected(cdev);
+		break;
+	case IO_SCH_UNREG_CDEV:
+	case IO_SCH_UNREG_ATTACH:
+	case IO_SCH_UNREG:
+		if (!cdev)
+			break;
+		if (cdev->private->state == DEV_STATE_SENSE_ID) {
+			/*
+			 * Note: delayed work triggered by this event
+			 * and repeated calls to sch_event are synchronized
+			 * by the above check for work_pending(cdev).
+			 */
+			dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
+		} else
+			ccw_device_set_notoper(cdev);
+		break;
+	case IO_SCH_NOP:
+		rc = 0;
+		goto out_unlock;
+	default:
+		break;
+	}
+	spin_unlock_irqrestore(sch->lock, flags);
+	/* All other actions require process context. */
+	if (!process)
+		goto out;
+	/* Handle attached ccw device. */
+	switch (action) {
+	case IO_SCH_ORPH_UNREG:
+	case IO_SCH_ORPH_ATTACH:
+		/* Move ccw device to orphanage. */
+		rc = ccw_device_move_to_orph(cdev);
+		if (rc)
+			goto out;
+		break;
+	case IO_SCH_UNREG_CDEV:
+	case IO_SCH_UNREG_ATTACH:
+		spin_lock_irqsave(sch->lock, flags);
+		sch_set_cdev(sch, NULL);
+		spin_unlock_irqrestore(sch->lock, flags);
+		/* Unregister ccw device. */
+		ccw_device_unregister(cdev);
+		break;
+	default:
+		break;
+	}
+	/* Handle subchannel. */
+	switch (action) {
+	case IO_SCH_ORPH_UNREG:
+	case IO_SCH_UNREG:
+		css_sch_device_unregister(sch);
+		break;
+	case IO_SCH_ORPH_ATTACH:
+	case IO_SCH_UNREG_ATTACH:
+	case IO_SCH_ATTACH:
+		dev_id.ssid = sch->schid.ssid;
+		dev_id.devno = sch->schib.pmcw.dev;
+		cdev = get_ccwdev_by_dev_id(&dev_id);
+		if (!cdev) {
+			sch_create_and_recog_new_device(sch);
+			break;
+		}
+		rc = ccw_device_move_to_sch(cdev, sch);
+		if (rc) {
+			/* Release reference from get_ccwdev_by_dev_id() */
+			put_device(&cdev->dev);
+			goto out;
+		}
+		spin_lock_irqsave(sch->lock, flags);
+		ccw_device_trigger_reprobe(cdev);
+		spin_unlock_irqrestore(sch->lock, flags);
+		/* Release reference from get_ccwdev_by_dev_id() */
+		put_device(&cdev->dev);
+		break;
+	default:
+		break;
+	}
+	return 0;
+
+out_unlock:
+	spin_unlock_irqrestore(sch->lock, flags);
+out:
+	return rc;
+}
+
+static void ccw_device_set_int_class(struct ccw_device *cdev)
+{
+	struct ccw_driver *cdrv = cdev->drv;
+
+	/* Note: we interpret class 0 in this context as an uninitialized
+	 * field since it translates to a non-I/O interrupt class. */
+	if (cdrv->int_class != 0)
+		cdev->private->int_class = cdrv->int_class;
+	else
+		cdev->private->int_class = IRQIO_CIO;
+}
+
+#ifdef CONFIG_CCW_CONSOLE
+int __init ccw_device_enable_console(struct ccw_device *cdev)
+{
+	struct subchannel *sch = to_subchannel(cdev->dev.parent);
+	int rc;
+
+	if (!cdev->drv || !cdev->handler)
+		return -EINVAL;
+
+	io_subchannel_init_fields(sch);
+	rc = cio_commit_config(sch);
+	if (rc)
+		return rc;
+	sch->driver = &io_subchannel_driver;
+	io_subchannel_recog(cdev, sch);
+	/* Now wait for the async. recognition to come to an end. */
+	spin_lock_irq(cdev->ccwlock);
+	while (!dev_fsm_final_state(cdev))
+		ccw_device_wait_idle(cdev);
+
+	/* Hold on to an extra reference while device is online. */
+	get_device(&cdev->dev);
+	rc = ccw_device_online(cdev);
+	if (rc)
+		goto out_unlock;
+
+	while (!dev_fsm_final_state(cdev))
+		ccw_device_wait_idle(cdev);
+
+	if (cdev->private->state == DEV_STATE_ONLINE)
+		cdev->online = 1;
+	else
+		rc = -EIO;
+out_unlock:
+	spin_unlock_irq(cdev->ccwlock);
+	if (rc) /* Give up online reference since onlining failed. */
+		put_device(&cdev->dev);
+	return rc;
+}
+
+struct ccw_device * __init ccw_device_create_console(struct ccw_driver *drv)
+{
+	struct io_subchannel_private *io_priv;
+	struct ccw_device *cdev;
+	struct subchannel *sch;
+
+	sch = cio_probe_console();
+	if (IS_ERR(sch))
+		return ERR_CAST(sch);
+
+	io_priv = kzalloc(sizeof(*io_priv), GFP_KERNEL | GFP_DMA);
+	if (!io_priv)
+		goto err_priv;
+	io_priv->dma_area = dma_alloc_coherent(&sch->dev,
+				sizeof(*io_priv->dma_area),
+				&io_priv->dma_area_dma, GFP_KERNEL);
+	if (!io_priv->dma_area)
+		goto err_dma_area;
+	set_io_private(sch, io_priv);
+	cdev = io_subchannel_create_ccwdev(sch);
+	if (IS_ERR(cdev)) {
+		dma_free_coherent(&sch->dev, sizeof(*io_priv->dma_area),
+				  io_priv->dma_area, io_priv->dma_area_dma);
+		set_io_private(sch, NULL);
+		put_device(&sch->dev);
+		kfree(io_priv);
+		return cdev;
+	}
+	cdev->drv = drv;
+	ccw_device_set_int_class(cdev);
+	return cdev;
+
+err_dma_area:
+	kfree(io_priv);
+err_priv:
+	put_device(&sch->dev);
+	return ERR_PTR(-ENOMEM);
+}
+
+void __init ccw_device_destroy_console(struct ccw_device *cdev)
+{
+	struct subchannel *sch = to_subchannel(cdev->dev.parent);
+	struct io_subchannel_private *io_priv = to_io_private(sch);
+
+	set_io_private(sch, NULL);
+	dma_free_coherent(&sch->dev, sizeof(*io_priv->dma_area),
+			  io_priv->dma_area, io_priv->dma_area_dma);
+	put_device(&sch->dev);
+	put_device(&cdev->dev);
+	kfree(io_priv);
+}
+
+/**
+ * ccw_device_wait_idle() - busy wait for device to become idle
+ * @cdev: ccw device
+ *
+ * Poll until activity control is zero, that is, no function or data
+ * transfer is pending/active.
+ * Called with device lock being held.
+ */
+void ccw_device_wait_idle(struct ccw_device *cdev)
+{
+	struct subchannel *sch = to_subchannel(cdev->dev.parent);
+
+	while (1) {
+		cio_tsch(sch);
+		if (sch->schib.scsw.cmd.actl == 0)
+			break;
+		udelay(100);
+	}
+}
+#endif
+
+/**
+ * get_ccwdev_by_busid() - obtain device from a bus id
+ * @cdrv: driver the device is owned by
+ * @bus_id: bus id of the device to be searched
+ *
+ * This function searches all devices owned by @cdrv for a device with a bus
+ * id matching @bus_id.
+ * Returns:
+ *  If a match is found, its reference count of the found device is increased
+ *  and it is returned; else %NULL is returned.
+ */
+struct ccw_device *get_ccwdev_by_busid(struct ccw_driver *cdrv,
+				       const char *bus_id)
+{
+	struct device *dev;
+
+	dev = driver_find_device_by_name(&cdrv->driver, bus_id);
+
+	return dev ? to_ccwdev(dev) : NULL;
+}
+
+/************************** device driver handling ************************/
+
+/* This is the implementation of the ccw_driver class. The probe, remove
+ * and release methods are initially very similar to the device_driver
+ * implementations, with the difference that they have ccw_device
+ * arguments.
+ *
+ * A ccw driver also contains the information that is needed for
+ * device matching.
+ */
+static int
+ccw_device_probe (struct device *dev)
+{
+	struct ccw_device *cdev = to_ccwdev(dev);
+	struct ccw_driver *cdrv = to_ccwdrv(dev->driver);
+	int ret;
+
+	cdev->drv = cdrv; /* to let the driver call _set_online */
+	ccw_device_set_int_class(cdev);
+	ret = cdrv->probe ? cdrv->probe(cdev) : -ENODEV;
+	if (ret) {
+		cdev->drv = NULL;
+		cdev->private->int_class = IRQIO_CIO;
+		return ret;
+	}
+
+	return 0;
+}
+
+static void ccw_device_remove(struct device *dev)
+{
+	struct ccw_device *cdev = to_ccwdev(dev);
+	struct ccw_driver *cdrv = cdev->drv;
+	struct subchannel *sch;
+	int ret;
+
+	if (cdrv->remove)
+		cdrv->remove(cdev);
+
+	spin_lock_irq(cdev->ccwlock);
+	if (cdev->online) {
+		cdev->online = 0;
+		ret = ccw_device_offline(cdev);
+		spin_unlock_irq(cdev->ccwlock);
+		if (ret == 0)
+			wait_event(cdev->private->wait_q,
+				   dev_fsm_final_state(cdev));
+		else
+			CIO_MSG_EVENT(0, "ccw_device_offline returned %d, "
+				      "device 0.%x.%04x\n",
+				      ret, cdev->private->dev_id.ssid,
+				      cdev->private->dev_id.devno);
+		/* Give up reference obtained in ccw_device_set_online(). */
+		put_device(&cdev->dev);
+		spin_lock_irq(cdev->ccwlock);
+	}
+	ccw_device_set_timeout(cdev, 0);
+	cdev->drv = NULL;
+	cdev->private->int_class = IRQIO_CIO;
+	sch = to_subchannel(cdev->dev.parent);
+	spin_unlock_irq(cdev->ccwlock);
+	io_subchannel_quiesce(sch);
+	__disable_cmf(cdev);
+}
+
+static void ccw_device_shutdown(struct device *dev)
+{
+	struct ccw_device *cdev;
+
+	cdev = to_ccwdev(dev);
+	if (cdev->drv && cdev->drv->shutdown)
+		cdev->drv->shutdown(cdev);
+	__disable_cmf(cdev);
+}
+
+static struct bus_type ccw_bus_type = {
+	.name   = "ccw",
+	.match  = ccw_bus_match,
+	.uevent = ccw_uevent,
+	.probe  = ccw_device_probe,
+	.remove = ccw_device_remove,
+	.shutdown = ccw_device_shutdown,
+};
+
+/**
+ * ccw_driver_register() - register a ccw driver
+ * @cdriver: driver to be registered
+ *
+ * This function is mainly a wrapper around driver_register().
+ * Returns:
+ *   %0 on success and a negative error value on failure.
+ */
+int ccw_driver_register(struct ccw_driver *cdriver)
+{
+	struct device_driver *drv = &cdriver->driver;
+
+	drv->bus = &ccw_bus_type;
+
+	return driver_register(drv);
+}
+
+/**
+ * ccw_driver_unregister() - deregister a ccw driver
+ * @cdriver: driver to be deregistered
+ *
+ * This function is mainly a wrapper around driver_unregister().
+ */
+void ccw_driver_unregister(struct ccw_driver *cdriver)
+{
+	driver_unregister(&cdriver->driver);
+}
+
+static void ccw_device_todo(struct work_struct *work)
+{
+	struct ccw_device_private *priv;
+	struct ccw_device *cdev;
+	struct subchannel *sch;
+	enum cdev_todo todo;
+
+	priv = container_of(work, struct ccw_device_private, todo_work);
+	cdev = priv->cdev;
+	sch = to_subchannel(cdev->dev.parent);
+	/* Find out todo. */
+	spin_lock_irq(cdev->ccwlock);
+	todo = priv->todo;
+	priv->todo = CDEV_TODO_NOTHING;
+	CIO_MSG_EVENT(4, "cdev_todo: cdev=0.%x.%04x todo=%d\n",
+		      priv->dev_id.ssid, priv->dev_id.devno, todo);
+	spin_unlock_irq(cdev->ccwlock);
+	/* Perform todo. */
+	switch (todo) {
+	case CDEV_TODO_ENABLE_CMF:
+		cmf_reenable(cdev);
+		break;
+	case CDEV_TODO_REBIND:
+		ccw_device_do_unbind_bind(cdev);
+		break;
+	case CDEV_TODO_REGISTER:
+		io_subchannel_register(cdev);
+		break;
+	case CDEV_TODO_UNREG_EVAL:
+		if (!sch_is_pseudo_sch(sch))
+			css_schedule_eval(sch->schid);
+		fallthrough;
+	case CDEV_TODO_UNREG:
+		spin_lock_irq(sch->lock);
+		sch_set_cdev(sch, NULL);
+		spin_unlock_irq(sch->lock);
+		ccw_device_unregister(cdev);
+		break;
+	default:
+		break;
+	}
+	/* Release workqueue ref. */
+	put_device(&cdev->dev);
+}
+
+/**
+ * ccw_device_sched_todo - schedule ccw device operation
+ * @cdev: ccw device
+ * @todo: todo
+ *
+ * Schedule the operation identified by @todo to be performed on the slow path
+ * workqueue. Do nothing if another operation with higher priority is already
+ * scheduled. Needs to be called with ccwdev lock held.
+ */
+void ccw_device_sched_todo(struct ccw_device *cdev, enum cdev_todo todo)
+{
+	CIO_MSG_EVENT(4, "cdev_todo: sched cdev=0.%x.%04x todo=%d\n",
+		      cdev->private->dev_id.ssid, cdev->private->dev_id.devno,
+		      todo);
+	if (cdev->private->todo >= todo)
+		return;
+	cdev->private->todo = todo;
+	/* Get workqueue ref. */
+	if (!get_device(&cdev->dev))
+		return;
+	if (!queue_work(cio_work_q, &cdev->private->todo_work)) {
+		/* Already queued, release workqueue ref. */
+		put_device(&cdev->dev);
+	}
+}
+
+/**
+ * ccw_device_siosl() - initiate logging
+ * @cdev: ccw device
+ *
+ * This function is used to invoke model-dependent logging within the channel
+ * subsystem.
+ */
+int ccw_device_siosl(struct ccw_device *cdev)
+{
+	struct subchannel *sch = to_subchannel(cdev->dev.parent);
+
+	return chsc_siosl(sch->schid);
+}
+EXPORT_SYMBOL_GPL(ccw_device_siosl);
+
+EXPORT_SYMBOL(ccw_device_set_online);
+EXPORT_SYMBOL(ccw_device_set_offline);
+EXPORT_SYMBOL(ccw_driver_register);
+EXPORT_SYMBOL(ccw_driver_unregister);
+EXPORT_SYMBOL(get_ccwdev_by_busid);