1 files changed, 649 insertions, 0 deletions

diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c
new file mode 100644
index 00000000..5f1dc6fb
--- /dev/null
+++ b/drivers/s390/cio/ccwgroup.c
@@ -0,0 +1,649 @@
+/*
+ *  bus driver for ccwgroup
+ *
+ *  Copyright IBM Corp. 2002, 2009
+ *
+ *  Author(s): Arnd Bergmann (arndb@de.ibm.com)
+ *	       Cornelia Huck (cornelia.huck@de.ibm.com)
+ */
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/ctype.h>
+#include <linux/dcache.h>
+
+#include <asm/ccwdev.h>
+#include <asm/ccwgroup.h>
+
+#define CCW_BUS_ID_SIZE		20
+
+/* In Linux 2.4, we had a channel device layer called "chandev"
+ * that did all sorts of obscure stuff for networking devices.
+ * This is another driver that serves as a replacement for just
+ * one of its functions, namely the translation of single subchannels
+ * to devices that use multiple subchannels.
+ */
+
+/* a device matches a driver if all its slave devices match the same
+ * entry of the driver */
+static int ccwgroup_bus_match(struct device *dev, struct device_driver * drv)
+{
+	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
+	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(drv);
+
+	if (gdev->creator_id == gdrv->driver_id)
+		return 1;
+
+	return 0;
+}
+
+static struct bus_type ccwgroup_bus_type;
+
+static void __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev)
+{
+	int i;
+	char str[8];
+
+	for (i = 0; i < gdev->count; i++) {
+		sprintf(str, "cdev%d", i);
+		sysfs_remove_link(&gdev->dev.kobj, str);
+		sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device");
+	}
+}
+
+/*
+ * Remove references from ccw devices to ccw group device and from
+ * ccw group device to ccw devices.
+ */
+static void __ccwgroup_remove_cdev_refs(struct ccwgroup_device *gdev)
+{
+	struct ccw_device *cdev;
+	int i;
+
+	for (i = 0; i < gdev->count; i++) {
+		cdev = gdev->cdev[i];
+		if (!cdev)
+			continue;
+		spin_lock_irq(cdev->ccwlock);
+		dev_set_drvdata(&cdev->dev, NULL);
+		spin_unlock_irq(cdev->ccwlock);
+		gdev->cdev[i] = NULL;
+		put_device(&cdev->dev);
+	}
+}
+
+static int ccwgroup_set_online(struct ccwgroup_device *gdev)
+{
+	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
+	int ret = 0;
+
+	if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
+		return -EAGAIN;
+	if (gdev->state == CCWGROUP_ONLINE)
+		goto out;
+	if (gdrv->set_online)
+		ret = gdrv->set_online(gdev);
+	if (ret)
+		goto out;
+
+	gdev->state = CCWGROUP_ONLINE;
+out:
+	atomic_set(&gdev->onoff, 0);
+	return ret;
+}
+
+static int ccwgroup_set_offline(struct ccwgroup_device *gdev)
+{
+	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
+	int ret = 0;
+
+	if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
+		return -EAGAIN;
+	if (gdev->state == CCWGROUP_OFFLINE)
+		goto out;
+	if (gdrv->set_offline)
+		ret = gdrv->set_offline(gdev);
+	if (ret)
+		goto out;
+
+	gdev->state = CCWGROUP_OFFLINE;
+out:
+	atomic_set(&gdev->onoff, 0);
+	return ret;
+}
+
+static ssize_t ccwgroup_online_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
+	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
+	unsigned long value;
+	int ret;
+
+	if (!dev->driver)
+		return -EINVAL;
+	if (!try_module_get(gdrv->driver.owner))
+		return -EINVAL;
+
+	ret = strict_strtoul(buf, 0, &value);
+	if (ret)
+		goto out;
+
+	if (value == 1)
+		ret = ccwgroup_set_online(gdev);
+	else if (value == 0)
+		ret = ccwgroup_set_offline(gdev);
+	else
+		ret = -EINVAL;
+out:
+	module_put(gdrv->driver.owner);
+	return (ret == 0) ? count : ret;
+}
+
+static ssize_t ccwgroup_online_show(struct device *dev,
+				    struct device_attribute *attr,
+				    char *buf)
+{
+	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
+	int online;
+
+	online = (gdev->state == CCWGROUP_ONLINE) ? 1 : 0;
+
+	return scnprintf(buf, PAGE_SIZE, "%d\n", online);
+}
+
+/*
+ * Provide an 'ungroup' attribute so the user can remove group devices no
+ * longer needed or accidentially created. Saves memory :)
+ */
+static void ccwgroup_ungroup_callback(struct device *dev)
+{
+	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
+
+	mutex_lock(&gdev->reg_mutex);
+	if (device_is_registered(&gdev->dev)) {
+		__ccwgroup_remove_symlinks(gdev);
+		device_unregister(dev);
+		__ccwgroup_remove_cdev_refs(gdev);
+	}
+	mutex_unlock(&gdev->reg_mutex);
+}
+
+static ssize_t ccwgroup_ungroup_store(struct device *dev,
+				      struct device_attribute *attr,
+				      const char *buf, size_t count)
+{
+	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
+	int rc;
+
+	/* Prevent concurrent online/offline processing and ungrouping. */
+	if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
+		return -EAGAIN;
+	if (gdev->state != CCWGROUP_OFFLINE) {
+		rc = -EINVAL;
+		goto out;
+	}
+	/* Note that we cannot unregister the device from one of its
+	 * attribute methods, so we have to use this roundabout approach.
+	 */
+	rc = device_schedule_callback(dev, ccwgroup_ungroup_callback);
+out:
+	if (rc) {
+		if (rc != -EAGAIN)
+			/* Release onoff "lock" when ungrouping failed. */
+			atomic_set(&gdev->onoff, 0);
+		return rc;
+	}
+	return count;
+}
+static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
+static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
+
+static struct attribute *ccwgroup_attrs[] = {
+	&dev_attr_online.attr,
+	&dev_attr_ungroup.attr,
+	NULL,
+};
+static struct attribute_group ccwgroup_attr_group = {
+	.attrs = ccwgroup_attrs,
+};
+static const struct attribute_group *ccwgroup_attr_groups[] = {
+	&ccwgroup_attr_group,
+	NULL,
+};
+
+static void ccwgroup_release(struct device *dev)
+{
+	kfree(to_ccwgroupdev(dev));
+}
+
+static int __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
+{
+	char str[8];
+	int i, rc;
+
+	for (i = 0; i < gdev->count; i++) {
+		rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj,
+				       &gdev->dev.kobj, "group_device");
+		if (rc) {
+			for (--i; i >= 0; i--)
+				sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
+						  "group_device");
+			return rc;
+		}
+	}
+	for (i = 0; i < gdev->count; i++) {
+		sprintf(str, "cdev%d", i);
+		rc = sysfs_create_link(&gdev->dev.kobj,
+				       &gdev->cdev[i]->dev.kobj, str);
+		if (rc) {
+			for (--i; i >= 0; i--) {
+				sprintf(str, "cdev%d", i);
+				sysfs_remove_link(&gdev->dev.kobj, str);
+			}
+			for (i = 0; i < gdev->count; i++)
+				sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
+						  "group_device");
+			return rc;
+		}
+	}
+	return 0;
+}
+
+static int __get_next_bus_id(const char **buf, char *bus_id)
+{
+	int rc, len;
+	char *start, *end;
+
+	start = (char *)*buf;
+	end = strchr(start, ',');
+	if (!end) {
+		/* Last entry. Strip trailing newline, if applicable. */
+		end = strchr(start, '\n');
+		if (end)
+			*end = '\0';
+		len = strlen(start) + 1;
+	} else {
+		len = end - start + 1;
+		end++;
+	}
+	if (len < CCW_BUS_ID_SIZE) {
+		strlcpy(bus_id, start, len);
+		rc = 0;
+	} else
+		rc = -EINVAL;
+	*buf = end;
+	return rc;
+}
+
+static int __is_valid_bus_id(char bus_id[CCW_BUS_ID_SIZE])
+{
+	int cssid, ssid, devno;
+
+	/* Must be of form %x.%x.%04x */
+	if (sscanf(bus_id, "%x.%1x.%04x", &cssid, &ssid, &devno) != 3)
+		return 0;
+	return 1;
+}
+
+/**
+ * ccwgroup_create_from_string() - create and register a ccw group device
+ * @root: parent device for the new device
+ * @creator_id: identifier of creating driver
+ * @cdrv: ccw driver of slave devices
+ * @num_devices: number of slave devices
+ * @buf: buffer containing comma separated bus ids of slave devices
+ *
+ * Create and register a new ccw group device as a child of @root. Slave
+ * devices are obtained from the list of bus ids given in @buf and must all
+ * belong to @cdrv.
+ * Returns:
+ *  %0 on success and an error code on failure.
+ * Context:
+ *  non-atomic
+ */
+int ccwgroup_create_from_string(struct device *root, unsigned int creator_id,
+				struct ccw_driver *cdrv, int num_devices,
+				const char *buf)
+{
+	struct ccwgroup_device *gdev;
+	int rc, i;
+	char tmp_bus_id[CCW_BUS_ID_SIZE];
+	const char *curr_buf;
+
+	gdev = kzalloc(sizeof(*gdev) + num_devices * sizeof(gdev->cdev[0]),
+		       GFP_KERNEL);
+	if (!gdev)
+		return -ENOMEM;
+
+	atomic_set(&gdev->onoff, 0);
+	mutex_init(&gdev->reg_mutex);
+	mutex_lock(&gdev->reg_mutex);
+	gdev->creator_id = creator_id;
+	gdev->count = num_devices;
+	gdev->dev.bus = &ccwgroup_bus_type;
+	gdev->dev.parent = root;
+	gdev->dev.release = ccwgroup_release;
+	device_initialize(&gdev->dev);
+
+	curr_buf = buf;
+	for (i = 0; i < num_devices && curr_buf; i++) {
+		rc = __get_next_bus_id(&curr_buf, tmp_bus_id);
+		if (rc != 0)
+			goto error;
+		if (!__is_valid_bus_id(tmp_bus_id)) {
+			rc = -EINVAL;
+			goto error;
+		}
+		gdev->cdev[i] = get_ccwdev_by_busid(cdrv, tmp_bus_id);
+		/*
+		 * All devices have to be of the same type in
+		 * order to be grouped.
+		 */
+		if (!gdev->cdev[i]
+		    || gdev->cdev[i]->id.driver_info !=
+		    gdev->cdev[0]->id.driver_info) {
+			rc = -EINVAL;
+			goto error;
+		}
+		/* Don't allow a device to belong to more than one group. */
+		spin_lock_irq(gdev->cdev[i]->ccwlock);
+		if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
+			spin_unlock_irq(gdev->cdev[i]->ccwlock);
+			rc = -EINVAL;
+			goto error;
+		}
+		dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
+		spin_unlock_irq(gdev->cdev[i]->ccwlock);
+	}
+	/* Check for sufficient number of bus ids. */
+	if (i < num_devices && !curr_buf) {
+		rc = -EINVAL;
+		goto error;
+	}
+	/* Check for trailing stuff. */
+	if (i == num_devices && strlen(curr_buf) > 0) {
+		rc = -EINVAL;
+		goto error;
+	}
+
+	dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev));
+	gdev->dev.groups = ccwgroup_attr_groups;
+	rc = device_add(&gdev->dev);
+	if (rc)
+		goto error;
+	rc = __ccwgroup_create_symlinks(gdev);
+	if (rc) {
+		device_del(&gdev->dev);
+		goto error;
+	}
+	mutex_unlock(&gdev->reg_mutex);
+	return 0;
+error:
+	for (i = 0; i < num_devices; i++)
+		if (gdev->cdev[i]) {
+			spin_lock_irq(gdev->cdev[i]->ccwlock);
+			if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
+				dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
+			spin_unlock_irq(gdev->cdev[i]->ccwlock);
+			put_device(&gdev->cdev[i]->dev);
+			gdev->cdev[i] = NULL;
+		}
+	mutex_unlock(&gdev->reg_mutex);
+	put_device(&gdev->dev);
+	return rc;
+}
+EXPORT_SYMBOL(ccwgroup_create_from_string);
+
+static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action,
+			     void *data)
+{
+	struct device *dev = data;
+
+	if (action == BUS_NOTIFY_UNBIND_DRIVER)
+		device_schedule_callback(dev, ccwgroup_ungroup_callback);
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block ccwgroup_nb = {
+	.notifier_call = ccwgroup_notifier
+};
+
+static int __init init_ccwgroup(void)
+{
+	int ret;
+
+	ret = bus_register(&ccwgroup_bus_type);
+	if (ret)
+		return ret;
+
+	ret = bus_register_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
+	if (ret)
+		bus_unregister(&ccwgroup_bus_type);
+
+	return ret;
+}
+
+static void __exit cleanup_ccwgroup(void)
+{
+	bus_unregister_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
+	bus_unregister(&ccwgroup_bus_type);
+}
+
+module_init(init_ccwgroup);
+module_exit(cleanup_ccwgroup);
+
+/************************** driver stuff ******************************/
+
+static int ccwgroup_probe(struct device *dev)
+{
+	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
+	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
+
+	return gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
+}
+
+static int ccwgroup_remove(struct device *dev)
+{
+	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
+	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
+
+	if (!dev->driver)
+		return 0;
+	if (gdrv->remove)
+		gdrv->remove(gdev);
+
+	return 0;
+}
+
+static void ccwgroup_shutdown(struct device *dev)
+{
+	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
+	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
+
+	if (!dev->driver)
+		return;
+	if (gdrv->shutdown)
+		gdrv->shutdown(gdev);
+}
+
+static int ccwgroup_pm_prepare(struct device *dev)
+{
+	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
+	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
+
+	/* Fail while device is being set online/offline. */
+	if (atomic_read(&gdev->onoff))
+		return -EAGAIN;
+
+	if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
+		return 0;
+
+	return gdrv->prepare ? gdrv->prepare(gdev) : 0;
+}
+
+static void ccwgroup_pm_complete(struct device *dev)
+{
+	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
+	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
+
+	if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
+		return;
+
+	if (gdrv->complete)
+		gdrv->complete(gdev);
+}
+
+static int ccwgroup_pm_freeze(struct device *dev)
+{
+	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
+	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
+
+	if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
+		return 0;
+
+	return gdrv->freeze ? gdrv->freeze(gdev) : 0;
+}
+
+static int ccwgroup_pm_thaw(struct device *dev)
+{
+	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
+	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
+
+	if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
+		return 0;
+
+	return gdrv->thaw ? gdrv->thaw(gdev) : 0;
+}
+
+static int ccwgroup_pm_restore(struct device *dev)
+{
+	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
+	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
+
+	if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
+		return 0;
+
+	return gdrv->restore ? gdrv->restore(gdev) : 0;
+}
+
+static const struct dev_pm_ops ccwgroup_pm_ops = {
+	.prepare = ccwgroup_pm_prepare,
+	.complete = ccwgroup_pm_complete,
+	.freeze = ccwgroup_pm_freeze,
+	.thaw = ccwgroup_pm_thaw,
+	.restore = ccwgroup_pm_restore,
+};
+
+static struct bus_type ccwgroup_bus_type = {
+	.name   = "ccwgroup",
+	.match  = ccwgroup_bus_match,
+	.probe  = ccwgroup_probe,
+	.remove = ccwgroup_remove,
+	.shutdown = ccwgroup_shutdown,
+	.pm = &ccwgroup_pm_ops,
+};
+
+/**
+ * ccwgroup_driver_register() - register a ccw group driver
+ * @cdriver: driver to be registered
+ *
+ * This function is mainly a wrapper around driver_register().
+ */
+int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
+{
+	/* register our new driver with the core */
+	cdriver->driver.bus = &ccwgroup_bus_type;
+
+	return driver_register(&cdriver->driver);
+}
+EXPORT_SYMBOL(ccwgroup_driver_register);
+
+static int __ccwgroup_match_all(struct device *dev, void *data)
+{
+	return 1;
+}
+
+/**
+ * ccwgroup_driver_unregister() - deregister a ccw group driver
+ * @cdriver: driver to be deregistered
+ *
+ * This function is mainly a wrapper around driver_unregister().
+ */
+void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
+{
+	struct device *dev;
+
+	/* We don't want ccwgroup devices to live longer than their driver. */
+	while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
+					 __ccwgroup_match_all))) {
+		struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
+
+		mutex_lock(&gdev->reg_mutex);
+		__ccwgroup_remove_symlinks(gdev);
+		device_unregister(dev);
+		__ccwgroup_remove_cdev_refs(gdev);
+		mutex_unlock(&gdev->reg_mutex);
+		put_device(dev);
+	}
+	driver_unregister(&cdriver->driver);
+}
+EXPORT_SYMBOL(ccwgroup_driver_unregister);
+
+/**
+ * ccwgroup_probe_ccwdev() - probe function for slave devices
+ * @cdev: ccw device to be probed
+ *
+ * This is a dummy probe function for ccw devices that are slave devices in
+ * a ccw group device.
+ * Returns:
+ *  always %0
+ */
+int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
+{
+	return 0;
+}
+EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
+
+/**
+ * ccwgroup_remove_ccwdev() - remove function for slave devices
+ * @cdev: ccw device to be removed
+ *
+ * This is a remove function for ccw devices that are slave devices in a ccw
+ * group device. It sets the ccw device offline and also deregisters the
+ * embedding ccw group device.
+ */
+void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
+{
+	struct ccwgroup_device *gdev;
+
+	/* Ignore offlining errors, device is gone anyway. */
+	ccw_device_set_offline(cdev);
+	/* If one of its devices is gone, the whole group is done for. */
+	spin_lock_irq(cdev->ccwlock);
+	gdev = dev_get_drvdata(&cdev->dev);
+	if (!gdev) {
+		spin_unlock_irq(cdev->ccwlock);
+		return;
+	}
+	/* Get ccwgroup device reference for local processing. */
+	get_device(&gdev->dev);
+	spin_unlock_irq(cdev->ccwlock);
+	/* Unregister group device. */
+	mutex_lock(&gdev->reg_mutex);
+	if (device_is_registered(&gdev->dev)) {
+		__ccwgroup_remove_symlinks(gdev);
+		device_unregister(&gdev->dev);
+		__ccwgroup_remove_cdev_refs(gdev);
+	}
+	mutex_unlock(&gdev->reg_mutex);
+	/* Release ccwgroup device reference for local processing. */
+	put_device(&gdev->dev);
+}
+EXPORT_SYMBOL(ccwgroup_remove_ccwdev);
+MODULE_LICENSE("GPL");