1 files changed, 260 insertions, 0 deletions
diff --git a/drivers/char/xillybus/xillybus_class.c b/drivers/char/xillybus/xillybus_class.c
new file mode 100644
index 000000000..0f238648d
--- /dev/null
+++ b/drivers/char/xillybus/xillybus_class.c
@@ -0,0 +1,260 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2021 Xillybus Ltd, http://xillybus.com
+ *
+ * Driver for the Xillybus class
+ */
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/cdev.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+
+#include "xillybus_class.h"
+
+MODULE_DESCRIPTION("Driver for Xillybus class");
+MODULE_AUTHOR("Eli Billauer, Xillybus Ltd.");
+MODULE_ALIAS("xillybus_class");
+MODULE_LICENSE("GPL v2");
+
+static DEFINE_MUTEX(unit_mutex);
+static LIST_HEAD(unit_list);
+static struct class *xillybus_class;
+
+#define UNITNAMELEN 16
+
+struct xilly_unit {
+	struct list_head list_entry;
+	void *private_data;
+
+	struct cdev *cdev;
+	char name[UNITNAMELEN];
+	int major;
+	int lowest_minor;
+	int num_nodes;
+};
+
+int xillybus_init_chrdev(struct device *dev,
+			 const struct file_operations *fops,
+			 struct module *owner,
+			 void *private_data,
+			 unsigned char *idt, unsigned int len,
+			 int num_nodes,
+			 const char *prefix, bool enumerate)
+{
+	int rc;
+	dev_t mdev;
+	int i;
+	char devname[48];
+
+	struct device *device;
+	size_t namelen;
+	struct xilly_unit *unit, *u;
+
+	unit = kzalloc(sizeof(*unit), GFP_KERNEL);
+
+	if (!unit)
+		return -ENOMEM;
+
+	mutex_lock(&unit_mutex);
+
+	if (!enumerate)
+		snprintf(unit->name, UNITNAMELEN, "%s", prefix);
+
+	for (i = 0; enumerate; i++) {
+		snprintf(unit->name, UNITNAMELEN, "%s_%02d",
+			 prefix, i);
+
+		enumerate = false;
+		list_for_each_entry(u, &unit_list, list_entry)
+			if (!strcmp(unit->name, u->name)) {
+				enumerate = true;
+				break;
+			}
+	}
+
+	rc = alloc_chrdev_region(&mdev, 0, num_nodes, unit->name);
+
+	if (rc) {
+		dev_warn(dev, "Failed to obtain major/minors");
+		goto fail_obtain;
+	}
+
+	unit->major = MAJOR(mdev);
+	unit->lowest_minor = MINOR(mdev);
+	unit->num_nodes = num_nodes;
+	unit->private_data = private_data;
+
+	unit->cdev = cdev_alloc();
+	if (!unit->cdev) {
+		rc = -ENOMEM;
+		goto unregister_chrdev;
+	}
+	unit->cdev->ops = fops;
+	unit->cdev->owner = owner;
+
+	rc = cdev_add(unit->cdev, MKDEV(unit->major, unit->lowest_minor),
+		      unit->num_nodes);
+	if (rc) {
+		dev_err(dev, "Failed to add cdev.\n");
+		/* kobject_put() is normally done by cdev_del() */
+		kobject_put(&unit->cdev->kobj);
+		goto unregister_chrdev;
+	}
+
+	for (i = 0; i < num_nodes; i++) {
+		namelen = strnlen(idt, len);
+
+		if (namelen == len) {
+			dev_err(dev, "IDT's list of names is too short. This is exceptionally weird, because its CRC is OK\n");
+			rc = -ENODEV;
+			goto unroll_device_create;
+		}
+
+		snprintf(devname, sizeof(devname), "%s_%s",
+			 unit->name, idt);
+
+		len -= namelen + 1;
+		idt += namelen + 1;
+
+		device = device_create(xillybus_class,
+				       NULL,
+				       MKDEV(unit->major,
+					     i + unit->lowest_minor),
+				       NULL,
+				       "%s", devname);
+
+		if (IS_ERR(device)) {
+			dev_err(dev, "Failed to create %s device. Aborting.\n",
+				devname);
+			rc = -ENODEV;
+			goto unroll_device_create;
+		}
+	}
+
+	if (len) {
+		dev_err(dev, "IDT's list of names is too long. This is exceptionally weird, because its CRC is OK\n");
+		rc = -ENODEV;
+		goto unroll_device_create;
+	}
+
+	list_add_tail(&unit->list_entry, &unit_list);
+
+	dev_info(dev, "Created %d device files.\n", num_nodes);
+
+	mutex_unlock(&unit_mutex);
+
+	return 0;
+
+unroll_device_create:
+	for (i--; i >= 0; i--)
+		device_destroy(xillybus_class, MKDEV(unit->major,
+						     i + unit->lowest_minor));
+
+	cdev_del(unit->cdev);
+
+unregister_chrdev:
+	unregister_chrdev_region(MKDEV(unit->major, unit->lowest_minor),
+				 unit->num_nodes);
+
+fail_obtain:
+	mutex_unlock(&unit_mutex);
+
+	kfree(unit);
+
+	return rc;
+}
+EXPORT_SYMBOL(xillybus_init_chrdev);
+
+void xillybus_cleanup_chrdev(void *private_data,
+			     struct device *dev)
+{
+	int minor;
+	struct xilly_unit *unit = NULL, *iter;
+
+	mutex_lock(&unit_mutex);
+
+	list_for_each_entry(iter, &unit_list, list_entry)
+		if (iter->private_data == private_data) {
+			unit = iter;
+			break;
+		}
+
+	if (!unit) {
+		dev_err(dev, "Weird bug: Failed to find unit\n");
+		mutex_unlock(&unit_mutex);
+		return;
+	}
+
+	for (minor = unit->lowest_minor;
+	     minor < (unit->lowest_minor + unit->num_nodes);
+	     minor++)
+		device_destroy(xillybus_class, MKDEV(unit->major, minor));
+
+	cdev_del(unit->cdev);
+
+	unregister_chrdev_region(MKDEV(unit->major, unit->lowest_minor),
+				 unit->num_nodes);
+
+	dev_info(dev, "Removed %d device files.\n",
+		 unit->num_nodes);
+
+	list_del(&unit->list_entry);
+	kfree(unit);
+
+	mutex_unlock(&unit_mutex);
+}
+EXPORT_SYMBOL(xillybus_cleanup_chrdev);
+
+int xillybus_find_inode(struct inode *inode,
+			void **private_data, int *index)
+{
+	int minor = iminor(inode);
+	int major = imajor(inode);
+	struct xilly_unit *unit = NULL, *iter;
+
+	mutex_lock(&unit_mutex);
+
+	list_for_each_entry(iter, &unit_list, list_entry)
+		if (iter->major == major &&
+		    minor >= iter->lowest_minor &&
+		    minor < (iter->lowest_minor + iter->num_nodes)) {
+			unit = iter;
+			break;
+		}
+
+	mutex_unlock(&unit_mutex);
+
+	if (!unit)
+		return -ENODEV;
+
+	*private_data = unit->private_data;
+	*index = minor - unit->lowest_minor;
+
+	return 0;
+}
+EXPORT_SYMBOL(xillybus_find_inode);
+
+static int __init xillybus_class_init(void)
+{
+	xillybus_class = class_create(THIS_MODULE, "xillybus");
+
+	if (IS_ERR(xillybus_class)) {
+		pr_warn("Failed to register xillybus class\n");
+
+		return PTR_ERR(xillybus_class);
+	}
+	return 0;
+}
+
+static void __exit xillybus_class_exit(void)
+{
+	class_destroy(xillybus_class);
+}
+
+module_init(xillybus_class_init);
+module_exit(xillybus_class_exit);