1 files changed, 132 insertions, 0 deletions
diff --git a/drivers/s390/char/tape_class.c b/drivers/s390/char/tape_class.c
new file mode 100644
index 000000000..b58df0dd0
--- /dev/null
+++ b/drivers/s390/char/tape_class.c
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright IBM Corp. 2004
+ *
+ * Tape class device support
+ *
+ * Author: Stefan Bader <shbader@de.ibm.com>
+ * Based on simple class device code by Greg K-H
+ */
+
+#define KMSG_COMPONENT "tape"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/slab.h>
+
+#include "tape_class.h"
+
+MODULE_AUTHOR("Stefan Bader <shbader@de.ibm.com>");
+MODULE_DESCRIPTION(
+	"Copyright IBM Corp. 2004   All Rights Reserved.\n"
+	"tape_class.c"
+);
+MODULE_LICENSE("GPL");
+
+static struct class *tape_class;
+
+/*
+ * Register a tape device and return a pointer to the cdev structure.
+ *
+ * device
+ *	The pointer to the struct device of the physical (base) device.
+ * drivername
+ *	The pointer to the drivers name for it's character devices.
+ * dev
+ *	The intended major/minor number. The major number may be 0 to
+ *	get a dynamic major number.
+ * fops
+ *	The pointer to the drivers file operations for the tape device.
+ * devname
+ *	The pointer to the name of the character device.
+ */
+struct tape_class_device *register_tape_dev(
+	struct device *		device,
+	dev_t			dev,
+	const struct file_operations *fops,
+	char *			device_name,
+	char *			mode_name)
+{
+	struct tape_class_device *	tcd;
+	int		rc;
+	char *		s;
+
+	tcd = kzalloc(sizeof(struct tape_class_device), GFP_KERNEL);
+	if (!tcd)
+		return ERR_PTR(-ENOMEM);
+
+	strlcpy(tcd->device_name, device_name, TAPECLASS_NAME_LEN);
+	for (s = strchr(tcd->device_name, '/'); s; s = strchr(s, '/'))
+		*s = '!';
+	strlcpy(tcd->mode_name, mode_name, TAPECLASS_NAME_LEN);
+	for (s = strchr(tcd->mode_name, '/'); s; s = strchr(s, '/'))
+		*s = '!';
+
+	tcd->char_device = cdev_alloc();
+	if (!tcd->char_device) {
+		rc = -ENOMEM;
+		goto fail_with_tcd;
+	}
+
+	tcd->char_device->owner = fops->owner;
+	tcd->char_device->ops   = fops;
+
+	rc = cdev_add(tcd->char_device, dev, 1);
+	if (rc)
+		goto fail_with_cdev;
+
+	tcd->class_device = device_create(tape_class, device,
+					  tcd->char_device->dev, NULL,
+					  "%s", tcd->device_name);
+	rc = PTR_ERR_OR_ZERO(tcd->class_device);
+	if (rc)
+		goto fail_with_cdev;
+	rc = sysfs_create_link(
+		&device->kobj,
+		&tcd->class_device->kobj,
+		tcd->mode_name
+	);
+	if (rc)
+		goto fail_with_class_device;
+
+	return tcd;
+
+fail_with_class_device:
+	device_destroy(tape_class, tcd->char_device->dev);
+
+fail_with_cdev:
+	cdev_del(tcd->char_device);
+
+fail_with_tcd:
+	kfree(tcd);
+
+	return ERR_PTR(rc);
+}
+EXPORT_SYMBOL(register_tape_dev);
+
+void unregister_tape_dev(struct device *device, struct tape_class_device *tcd)
+{
+	if (tcd != NULL && !IS_ERR(tcd)) {
+		sysfs_remove_link(&device->kobj, tcd->mode_name);
+		device_destroy(tape_class, tcd->char_device->dev);
+		cdev_del(tcd->char_device);
+		kfree(tcd);
+	}
+}
+EXPORT_SYMBOL(unregister_tape_dev);
+
+
+static int __init tape_init(void)
+{
+	tape_class = class_create(THIS_MODULE, "tape390");
+
+	return 0;
+}
+
+static void __exit tape_exit(void)
+{
+	class_destroy(tape_class);
+	tape_class = NULL;
+}
+
+postcore_initcall(tape_init);
+module_exit(tape_exit);