1 files changed, 553 insertions, 0 deletions

diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c
new file mode 100644
index 000000000..f0538609d
--- /dev/null
+++ b/drivers/s390/cio/ccwgroup.c
@@ -0,0 +1,553 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  bus driver for ccwgroup
+ *
+ *  Copyright IBM Corp. 2002, 2012
+ *
+ *  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/cio.h>
+#include <asm/ccwdev.h>
+#include <asm/ccwgroup.h>
+
+#include "device.h"
+
+#define CCW_BUS_ID_SIZE		10
+
+/* 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.
+ */
+
+static struct bus_type ccwgroup_bus_type;
+
+static void __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev)
+{
+	int i;
+	char str[16];
+
+	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");
+	}
+}
+
+/**
+ * ccwgroup_set_online() - enable a ccwgroup device
+ * @gdev: target ccwgroup device
+ *
+ * This function attempts to put the ccwgroup device into the online state.
+ * Returns:
+ *  %0 on success and a negative error value on failure.
+ */
+int ccwgroup_set_online(struct ccwgroup_device *gdev)
+{
+	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
+	int ret = -EINVAL;
+
+	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;
+}
+EXPORT_SYMBOL(ccwgroup_set_online);
+
+/**
+ * ccwgroup_set_offline() - disable a ccwgroup device
+ * @gdev: target ccwgroup device
+ * @call_gdrv: Call the registered gdrv set_offline function
+ *
+ * This function attempts to put the ccwgroup device into the offline state.
+ * Returns:
+ *  %0 on success and a negative error value on failure.
+ */
+int ccwgroup_set_offline(struct ccwgroup_device *gdev, bool call_gdrv)
+{
+	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
+	int ret = -EINVAL;
+
+	if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
+		return -EAGAIN;
+	if (gdev->state == CCWGROUP_OFFLINE)
+		goto out;
+	if (!call_gdrv) {
+		ret = 0;
+		goto offline;
+	}
+	if (gdrv->set_offline)
+		ret = gdrv->set_offline(gdev);
+	if (ret)
+		goto out;
+
+offline:
+	gdev->state = CCWGROUP_OFFLINE;
+out:
+	atomic_set(&gdev->onoff, 0);
+	return ret;
+}
+EXPORT_SYMBOL(ccwgroup_set_offline);
+
+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);
+	unsigned long value;
+	int ret;
+
+	device_lock(dev);
+	if (!dev->driver) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = kstrtoul(buf, 0, &value);
+	if (ret)
+		goto out;
+
+	if (value == 1)
+		ret = ccwgroup_set_online(gdev);
+	else if (value == 0)
+		ret = ccwgroup_set_offline(gdev, true);
+	else
+		ret = -EINVAL;
+out:
+	device_unlock(dev);
+	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(struct ccwgroup_device *gdev)
+{
+	mutex_lock(&gdev->reg_mutex);
+	if (device_is_registered(&gdev->dev)) {
+		__ccwgroup_remove_symlinks(gdev);
+		device_unregister(&gdev->dev);
+	}
+	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 = 0;
+
+	/* 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;
+	}
+
+	if (device_remove_file_self(dev, attr))
+		ccwgroup_ungroup(gdev);
+	else
+		rc = -ENODEV;
+out:
+	if (rc) {
+		/* 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_dev_attrs[] = {
+	&dev_attr_online.attr,
+	&dev_attr_ungroup.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(ccwgroup_dev);
+
+static void ccwgroup_ungroup_workfn(struct work_struct *work)
+{
+	struct ccwgroup_device *gdev =
+		container_of(work, struct ccwgroup_device, ungroup_work);
+
+	ccwgroup_ungroup(gdev);
+	put_device(&gdev->dev);
+}
+
+static void ccwgroup_release(struct device *dev)
+{
+	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
+	unsigned int i;
+
+	for (i = 0; i < gdev->count; i++) {
+		struct ccw_device *cdev = gdev->cdev[i];
+		unsigned long flags;
+
+		if (cdev) {
+			spin_lock_irqsave(cdev->ccwlock, flags);
+			if (dev_get_drvdata(&cdev->dev) == gdev)
+				dev_set_drvdata(&cdev->dev, NULL);
+			spin_unlock_irqrestore(cdev->ccwlock, flags);
+			put_device(&cdev->dev);
+		}
+	}
+
+	kfree(gdev);
+}
+
+static int __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
+{
+	char str[16];
+	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_id(const char **buf, struct ccw_dev_id *id)
+{
+	unsigned int cssid, ssid, devno;
+	int ret = 0, 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) {
+		if (sscanf(start, "%2x.%1x.%04x", &cssid, &ssid, &devno) != 3)
+			ret = -EINVAL;
+	} else
+		ret = -EINVAL;
+
+	if (!ret) {
+		id->ssid = ssid;
+		id->devno = devno;
+	}
+	*buf = end;
+	return ret;
+}
+
+/**
+ * ccwgroup_create_dev() - create and register a ccw group device
+ * @parent: parent device for the new device
+ * @gdrv: driver for the new group device
+ * @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 @parent. Slave
+ * devices are obtained from the list of bus ids given in @buf.
+ * Returns:
+ *  %0 on success and an error code on failure.
+ * Context:
+ *  non-atomic
+ */
+int ccwgroup_create_dev(struct device *parent, struct ccwgroup_driver *gdrv,
+			int num_devices, const char *buf)
+{
+	struct ccwgroup_device *gdev;
+	struct ccw_dev_id dev_id;
+	int rc, i;
+
+	if (num_devices < 1)
+		return -EINVAL;
+
+	gdev = kzalloc(struct_size(gdev, cdev, num_devices), GFP_KERNEL);
+	if (!gdev)
+		return -ENOMEM;
+
+	atomic_set(&gdev->onoff, 0);
+	mutex_init(&gdev->reg_mutex);
+	mutex_lock(&gdev->reg_mutex);
+	INIT_WORK(&gdev->ungroup_work, ccwgroup_ungroup_workfn);
+	gdev->count = num_devices;
+	gdev->dev.bus = &ccwgroup_bus_type;
+	gdev->dev.parent = parent;
+	gdev->dev.release = ccwgroup_release;
+	device_initialize(&gdev->dev);
+
+	for (i = 0; i < num_devices && buf; i++) {
+		rc = __get_next_id(&buf, &dev_id);
+		if (rc != 0)
+			goto error;
+		gdev->cdev[i] = get_ccwdev_by_dev_id(&dev_id);
+		/*
+		 * All devices have to be of the same type in
+		 * order to be grouped.
+		 */
+		if (!gdev->cdev[i] || !gdev->cdev[i]->drv ||
+		    gdev->cdev[i]->drv != gdev->cdev[0]->drv ||
+		    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) {
+		rc = -EINVAL;
+		goto error;
+	}
+	/* Check for trailing stuff. */
+	if (i == num_devices && buf && strlen(buf) > 0) {
+		rc = -EINVAL;
+		goto error;
+	}
+	/* Check if the devices are bound to the required ccw driver. */
+	if (gdrv && gdrv->ccw_driver &&
+	    gdev->cdev[0]->drv != gdrv->ccw_driver) {
+		rc = -EINVAL;
+		goto error;
+	}
+
+	dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev));
+
+	if (gdrv) {
+		gdev->dev.driver = &gdrv->driver;
+		rc = gdrv->setup ? gdrv->setup(gdev) : 0;
+		if (rc)
+			goto error;
+	}
+	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:
+	mutex_unlock(&gdev->reg_mutex);
+	put_device(&gdev->dev);
+	return rc;
+}
+EXPORT_SYMBOL(ccwgroup_create_dev);
+
+static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action,
+			     void *data)
+{
+	struct ccwgroup_device *gdev = to_ccwgroupdev(data);
+
+	if (action == BUS_NOTIFY_UNBOUND_DRIVER) {
+		get_device(&gdev->dev);
+		schedule_work(&gdev->ungroup_work);
+	}
+
+	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 void ccwgroup_remove(struct device *dev)
+{
+	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
+	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
+
+	if (gdrv->remove)
+		gdrv->remove(gdev);
+}
+
+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 struct bus_type ccwgroup_bus_type = {
+	.name   = "ccwgroup",
+	.dev_groups = ccwgroup_dev_groups,
+	.remove = ccwgroup_remove,
+	.shutdown = ccwgroup_shutdown,
+};
+
+bool dev_is_ccwgroup(struct device *dev)
+{
+	return dev->bus == &ccwgroup_bus_type;
+}
+EXPORT_SYMBOL(dev_is_ccwgroup);
+
+/**
+ * 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);
+
+/**
+ * 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)
+{
+	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. */
+	ccwgroup_ungroup(gdev);
+	/* Release ccwgroup device reference for local processing. */
+	put_device(&gdev->dev);
+}
+EXPORT_SYMBOL(ccwgroup_remove_ccwdev);
+MODULE_LICENSE("GPL");