1 // SPDX-License-Identifier: GPL-2.0-only
3 * Mediated device Core Driver
5 * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
6 * Author: Neo Jia <cjia@nvidia.com>
7 * Kirti Wankhede <kwankhede@nvidia.com>
10 #include <linux/module.h>
11 #include <linux/device.h>
12 #include <linux/slab.h>
13 #include <linux/uuid.h>
14 #include <linux/sysfs.h>
15 #include <linux/mdev.h>
17 #include "mdev_private.h"
19 #define DRIVER_VERSION "0.1"
20 #define DRIVER_AUTHOR "NVIDIA Corporation"
21 #define DRIVER_DESC "Mediated device Core Driver"
23 static LIST_HEAD(parent_list);
24 static DEFINE_MUTEX(parent_list_lock);
25 static struct class_compat *mdev_bus_compat_class;
27 static LIST_HEAD(mdev_list);
28 static DEFINE_MUTEX(mdev_list_lock);
30 struct device *mdev_parent_dev(struct mdev_device *mdev)
32 return mdev->type->parent->dev;
34 EXPORT_SYMBOL(mdev_parent_dev);
37 * Return the index in supported_type_groups that this mdev_device was created
40 unsigned int mdev_get_type_group_id(struct mdev_device *mdev)
42 return mdev->type->type_group_id;
44 EXPORT_SYMBOL(mdev_get_type_group_id);
47 * Used in mdev_type_attribute sysfs functions to return the index in the
48 * supported_type_groups that the sysfs is called from.
50 unsigned int mtype_get_type_group_id(struct mdev_type *mtype)
52 return mtype->type_group_id;
54 EXPORT_SYMBOL(mtype_get_type_group_id);
57 * Used in mdev_type_attribute sysfs functions to return the parent struct
60 struct device *mtype_get_parent_dev(struct mdev_type *mtype)
62 return mtype->parent->dev;
64 EXPORT_SYMBOL(mtype_get_parent_dev);
66 /* Should be called holding parent_list_lock */
67 static struct mdev_parent *__find_parent_device(struct device *dev)
69 struct mdev_parent *parent;
71 list_for_each_entry(parent, &parent_list, next) {
72 if (parent->dev == dev)
78 void mdev_release_parent(struct kref *kref)
80 struct mdev_parent *parent = container_of(kref, struct mdev_parent,
82 struct device *dev = parent->dev;
88 /* Caller must hold parent unreg_sem read or write lock */
89 static void mdev_device_remove_common(struct mdev_device *mdev)
91 struct mdev_parent *parent = mdev->type->parent;
94 mdev_remove_sysfs_files(mdev);
95 device_del(&mdev->dev);
96 lockdep_assert_held(&parent->unreg_sem);
97 ret = parent->ops->remove(mdev);
99 dev_err(&mdev->dev, "Remove failed: err=%d\n", ret);
101 /* Balances with device_initialize() */
102 put_device(&mdev->dev);
105 static int mdev_device_remove_cb(struct device *dev, void *data)
107 struct mdev_device *mdev = mdev_from_dev(dev);
110 mdev_device_remove_common(mdev);
115 * mdev_register_device : Register a device
116 * @dev: device structure representing parent device.
117 * @ops: Parent device operation structure to be registered.
119 * Add device to list of registered parent devices.
120 * Returns a negative value on error, otherwise 0.
122 int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
125 struct mdev_parent *parent;
126 char *env_string = "MDEV_STATE=registered";
127 char *envp[] = { env_string, NULL };
129 /* check for mandatory ops */
130 if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups)
133 dev = get_device(dev);
137 /* Not mandatory, but its absence could be a problem */
139 dev_info(dev, "Driver cannot be asked to release device\n");
141 mutex_lock(&parent_list_lock);
143 /* Check for duplicate */
144 parent = __find_parent_device(dev);
151 parent = kzalloc(sizeof(*parent), GFP_KERNEL);
157 kref_init(&parent->ref);
158 init_rwsem(&parent->unreg_sem);
163 if (!mdev_bus_compat_class) {
164 mdev_bus_compat_class = class_compat_register("mdev_bus");
165 if (!mdev_bus_compat_class) {
171 ret = parent_create_sysfs_files(parent);
175 ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
177 dev_warn(dev, "Failed to create compatibility class link\n");
179 list_add(&parent->next, &parent_list);
180 mutex_unlock(&parent_list_lock);
182 dev_info(dev, "MDEV: Registered\n");
183 kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
188 mutex_unlock(&parent_list_lock);
190 mdev_put_parent(parent);
195 EXPORT_SYMBOL(mdev_register_device);
198 * mdev_unregister_device : Unregister a parent device
199 * @dev: device structure representing parent device.
201 * Remove device from list of registered parent devices. Give a chance to free
202 * existing mediated devices for given device.
205 void mdev_unregister_device(struct device *dev)
207 struct mdev_parent *parent;
208 char *env_string = "MDEV_STATE=unregistered";
209 char *envp[] = { env_string, NULL };
211 mutex_lock(&parent_list_lock);
212 parent = __find_parent_device(dev);
215 mutex_unlock(&parent_list_lock);
218 dev_info(dev, "MDEV: Unregistering\n");
220 list_del(&parent->next);
221 mutex_unlock(&parent_list_lock);
223 down_write(&parent->unreg_sem);
225 class_compat_remove_link(mdev_bus_compat_class, dev, NULL);
227 device_for_each_child(dev, NULL, mdev_device_remove_cb);
229 parent_remove_sysfs_files(parent);
230 up_write(&parent->unreg_sem);
232 mdev_put_parent(parent);
234 /* We still have the caller's reference to use for the uevent */
235 kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
237 EXPORT_SYMBOL(mdev_unregister_device);
239 static void mdev_device_release(struct device *dev)
241 struct mdev_device *mdev = to_mdev_device(dev);
243 /* Pairs with the get in mdev_device_create() */
244 kobject_put(&mdev->type->kobj);
246 mutex_lock(&mdev_list_lock);
247 list_del(&mdev->next);
248 mutex_unlock(&mdev_list_lock);
250 dev_dbg(&mdev->dev, "MDEV: destroying\n");
254 int mdev_device_create(struct mdev_type *type, const guid_t *uuid)
257 struct mdev_device *mdev, *tmp;
258 struct mdev_parent *parent = type->parent;
260 mutex_lock(&mdev_list_lock);
262 /* Check for duplicate */
263 list_for_each_entry(tmp, &mdev_list, next) {
264 if (guid_equal(&tmp->uuid, uuid)) {
265 mutex_unlock(&mdev_list_lock);
270 mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
272 mutex_unlock(&mdev_list_lock);
276 device_initialize(&mdev->dev);
277 mdev->dev.parent = parent->dev;
278 mdev->dev.bus = &mdev_bus_type;
279 mdev->dev.release = mdev_device_release;
280 mdev->dev.groups = parent->ops->mdev_attr_groups;
282 /* Pairs with the put in mdev_device_release() */
283 kobject_get(&type->kobj);
285 guid_copy(&mdev->uuid, uuid);
286 list_add(&mdev->next, &mdev_list);
287 mutex_unlock(&mdev_list_lock);
289 ret = dev_set_name(&mdev->dev, "%pUl", uuid);
293 /* Check if parent unregistration has started */
294 if (!down_read_trylock(&parent->unreg_sem)) {
299 ret = parent->ops->create(mdev);
303 ret = device_add(&mdev->dev);
307 ret = mdev_create_sysfs_files(mdev);
312 dev_dbg(&mdev->dev, "MDEV: created\n");
313 up_read(&parent->unreg_sem);
318 device_del(&mdev->dev);
320 parent->ops->remove(mdev);
322 up_read(&parent->unreg_sem);
324 put_device(&mdev->dev);
328 int mdev_device_remove(struct mdev_device *mdev)
330 struct mdev_device *tmp;
331 struct mdev_parent *parent = mdev->type->parent;
333 mutex_lock(&mdev_list_lock);
334 list_for_each_entry(tmp, &mdev_list, next) {
340 mutex_unlock(&mdev_list_lock);
345 mutex_unlock(&mdev_list_lock);
349 mdev->active = false;
350 mutex_unlock(&mdev_list_lock);
352 /* Check if parent unregistration has started */
353 if (!down_read_trylock(&parent->unreg_sem))
356 mdev_device_remove_common(mdev);
357 up_read(&parent->unreg_sem);
361 static int __init mdev_init(void)
363 return mdev_bus_register();
366 static void __exit mdev_exit(void)
368 if (mdev_bus_compat_class)
369 class_compat_unregister(mdev_bus_compat_class);
371 mdev_bus_unregister();
374 module_init(mdev_init)
375 module_exit(mdev_exit)
377 MODULE_VERSION(DRIVER_VERSION);
378 MODULE_LICENSE("GPL v2");
379 MODULE_AUTHOR(DRIVER_AUTHOR);
380 MODULE_DESCRIPTION(DRIVER_DESC);
381 MODULE_SOFTDEP("post: vfio_mdev");