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path: root/drivers/char/xillybus/xillybus_class.c
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Diffstat (limited to 'drivers/char/xillybus/xillybus_class.c')
-rw-r--r--drivers/char/xillybus/xillybus_class.c256
1 files changed, 256 insertions, 0 deletions
diff --git a/drivers/char/xillybus/xillybus_class.c b/drivers/char/xillybus/xillybus_class.c
new file mode 100644
index 0000000000..c92a628e38
--- /dev/null
+++ b/drivers/char/xillybus/xillybus_class.c
@@ -0,0 +1,256 @@
+// 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 const struct class xillybus_class = {
+ .name = "xillybus",
+};
+
+#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;
+ }
+
+ if (!unit) {
+ mutex_unlock(&unit_mutex);
+ return -ENODEV;
+ }
+
+ *private_data = unit->private_data;
+ *index = minor - unit->lowest_minor;
+
+ mutex_unlock(&unit_mutex);
+ return 0;
+}
+EXPORT_SYMBOL(xillybus_find_inode);
+
+static int __init xillybus_class_init(void)
+{
+ return class_register(&xillybus_class);
+}
+
+static void __exit xillybus_class_exit(void)
+{
+ class_unregister(&xillybus_class);
+}
+
+module_init(xillybus_class_init);
+module_exit(xillybus_class_exit);