1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Mediated device Core Driver
4 *
5 * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
6 * Author: Neo Jia <cjia@nvidia.com>
7 * Kirti Wankhede <kwankhede@nvidia.com>
8 */
9
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>
16
17 #include "mdev_private.h"
18
19 #define DRIVER_VERSION "0.1"
20 #define DRIVER_AUTHOR "NVIDIA Corporation"
21 #define DRIVER_DESC "Mediated device Core Driver"
22
23 static LIST_HEAD(parent_list);
24 static DEFINE_MUTEX(parent_list_lock);
25 static struct class_compat *mdev_bus_compat_class;
26
27 static LIST_HEAD(mdev_list);
28 static DEFINE_MUTEX(mdev_list_lock);
29
mdev_parent_dev(struct mdev_device * mdev)30 struct device *mdev_parent_dev(struct mdev_device *mdev)
31 {
32 return mdev->type->parent->dev;
33 }
34 EXPORT_SYMBOL(mdev_parent_dev);
35
36 /*
37 * Return the index in supported_type_groups that this mdev_device was created
38 * from.
39 */
mdev_get_type_group_id(struct mdev_device * mdev)40 unsigned int mdev_get_type_group_id(struct mdev_device *mdev)
41 {
42 return mdev->type->type_group_id;
43 }
44 EXPORT_SYMBOL(mdev_get_type_group_id);
45
46 /*
47 * Used in mdev_type_attribute sysfs functions to return the index in the
48 * supported_type_groups that the sysfs is called from.
49 */
mtype_get_type_group_id(struct mdev_type * mtype)50 unsigned int mtype_get_type_group_id(struct mdev_type *mtype)
51 {
52 return mtype->type_group_id;
53 }
54 EXPORT_SYMBOL(mtype_get_type_group_id);
55
56 /*
57 * Used in mdev_type_attribute sysfs functions to return the parent struct
58 * device
59 */
mtype_get_parent_dev(struct mdev_type * mtype)60 struct device *mtype_get_parent_dev(struct mdev_type *mtype)
61 {
62 return mtype->parent->dev;
63 }
64 EXPORT_SYMBOL(mtype_get_parent_dev);
65
66 /* Should be called holding parent_list_lock */
__find_parent_device(struct device * dev)67 static struct mdev_parent *__find_parent_device(struct device *dev)
68 {
69 struct mdev_parent *parent;
70
71 list_for_each_entry(parent, &parent_list, next) {
72 if (parent->dev == dev)
73 return parent;
74 }
75 return NULL;
76 }
77
mdev_release_parent(struct kref * kref)78 void mdev_release_parent(struct kref *kref)
79 {
80 struct mdev_parent *parent = container_of(kref, struct mdev_parent,
81 ref);
82 struct device *dev = parent->dev;
83
84 kfree(parent);
85 put_device(dev);
86 }
87
88 /* Caller must hold parent unreg_sem read or write lock */
mdev_device_remove_common(struct mdev_device * mdev)89 static void mdev_device_remove_common(struct mdev_device *mdev)
90 {
91 struct mdev_parent *parent = mdev->type->parent;
92
93 mdev_remove_sysfs_files(mdev);
94 device_del(&mdev->dev);
95 lockdep_assert_held(&parent->unreg_sem);
96 /* Balances with device_initialize() */
97 put_device(&mdev->dev);
98 }
99
mdev_device_remove_cb(struct device * dev,void * data)100 static int mdev_device_remove_cb(struct device *dev, void *data)
101 {
102 struct mdev_device *mdev = mdev_from_dev(dev);
103
104 if (mdev)
105 mdev_device_remove_common(mdev);
106 return 0;
107 }
108
109 /*
110 * mdev_register_device : Register a device
111 * @dev: device structure representing parent device.
112 * @mdev_driver: Device driver to bind to the newly created mdev
113 *
114 * Add device to list of registered parent devices.
115 * Returns a negative value on error, otherwise 0.
116 */
mdev_register_device(struct device * dev,struct mdev_driver * mdev_driver)117 int mdev_register_device(struct device *dev, struct mdev_driver *mdev_driver)
118 {
119 int ret;
120 struct mdev_parent *parent;
121 char *env_string = "MDEV_STATE=registered";
122 char *envp[] = { env_string, NULL };
123
124 /* check for mandatory ops */
125 if (!mdev_driver->supported_type_groups)
126 return -EINVAL;
127
128 dev = get_device(dev);
129 if (!dev)
130 return -EINVAL;
131
132 mutex_lock(&parent_list_lock);
133
134 /* Check for duplicate */
135 parent = __find_parent_device(dev);
136 if (parent) {
137 parent = NULL;
138 ret = -EEXIST;
139 goto add_dev_err;
140 }
141
142 parent = kzalloc(sizeof(*parent), GFP_KERNEL);
143 if (!parent) {
144 ret = -ENOMEM;
145 goto add_dev_err;
146 }
147
148 kref_init(&parent->ref);
149 init_rwsem(&parent->unreg_sem);
150
151 parent->dev = dev;
152 parent->mdev_driver = mdev_driver;
153
154 if (!mdev_bus_compat_class) {
155 mdev_bus_compat_class = class_compat_register("mdev_bus");
156 if (!mdev_bus_compat_class) {
157 ret = -ENOMEM;
158 goto add_dev_err;
159 }
160 }
161
162 ret = parent_create_sysfs_files(parent);
163 if (ret)
164 goto add_dev_err;
165
166 ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
167 if (ret)
168 dev_warn(dev, "Failed to create compatibility class link\n");
169
170 list_add(&parent->next, &parent_list);
171 mutex_unlock(&parent_list_lock);
172
173 dev_info(dev, "MDEV: Registered\n");
174 kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
175
176 return 0;
177
178 add_dev_err:
179 mutex_unlock(&parent_list_lock);
180 if (parent)
181 mdev_put_parent(parent);
182 else
183 put_device(dev);
184 return ret;
185 }
186 EXPORT_SYMBOL(mdev_register_device);
187
188 /*
189 * mdev_unregister_device : Unregister a parent device
190 * @dev: device structure representing parent device.
191 *
192 * Remove device from list of registered parent devices. Give a chance to free
193 * existing mediated devices for given device.
194 */
195
mdev_unregister_device(struct device * dev)196 void mdev_unregister_device(struct device *dev)
197 {
198 struct mdev_parent *parent;
199 char *env_string = "MDEV_STATE=unregistered";
200 char *envp[] = { env_string, NULL };
201
202 mutex_lock(&parent_list_lock);
203 parent = __find_parent_device(dev);
204
205 if (!parent) {
206 mutex_unlock(&parent_list_lock);
207 return;
208 }
209 dev_info(dev, "MDEV: Unregistering\n");
210
211 list_del(&parent->next);
212 mutex_unlock(&parent_list_lock);
213
214 down_write(&parent->unreg_sem);
215
216 class_compat_remove_link(mdev_bus_compat_class, dev, NULL);
217
218 device_for_each_child(dev, NULL, mdev_device_remove_cb);
219
220 parent_remove_sysfs_files(parent);
221 up_write(&parent->unreg_sem);
222
223 mdev_put_parent(parent);
224
225 /* We still have the caller's reference to use for the uevent */
226 kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
227 }
228 EXPORT_SYMBOL(mdev_unregister_device);
229
mdev_device_release(struct device * dev)230 static void mdev_device_release(struct device *dev)
231 {
232 struct mdev_device *mdev = to_mdev_device(dev);
233
234 /* Pairs with the get in mdev_device_create() */
235 kobject_put(&mdev->type->kobj);
236
237 mutex_lock(&mdev_list_lock);
238 list_del(&mdev->next);
239 mutex_unlock(&mdev_list_lock);
240
241 dev_dbg(&mdev->dev, "MDEV: destroying\n");
242 kfree(mdev);
243 }
244
mdev_device_create(struct mdev_type * type,const guid_t * uuid)245 int mdev_device_create(struct mdev_type *type, const guid_t *uuid)
246 {
247 int ret;
248 struct mdev_device *mdev, *tmp;
249 struct mdev_parent *parent = type->parent;
250 struct mdev_driver *drv = parent->mdev_driver;
251
252 mutex_lock(&mdev_list_lock);
253
254 /* Check for duplicate */
255 list_for_each_entry(tmp, &mdev_list, next) {
256 if (guid_equal(&tmp->uuid, uuid)) {
257 mutex_unlock(&mdev_list_lock);
258 return -EEXIST;
259 }
260 }
261
262 mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
263 if (!mdev) {
264 mutex_unlock(&mdev_list_lock);
265 return -ENOMEM;
266 }
267
268 device_initialize(&mdev->dev);
269 mdev->dev.parent = parent->dev;
270 mdev->dev.bus = &mdev_bus_type;
271 mdev->dev.release = mdev_device_release;
272 mdev->dev.groups = mdev_device_groups;
273 mdev->type = type;
274 /* Pairs with the put in mdev_device_release() */
275 kobject_get(&type->kobj);
276
277 guid_copy(&mdev->uuid, uuid);
278 list_add(&mdev->next, &mdev_list);
279 mutex_unlock(&mdev_list_lock);
280
281 ret = dev_set_name(&mdev->dev, "%pUl", uuid);
282 if (ret)
283 goto out_put_device;
284
285 /* Check if parent unregistration has started */
286 if (!down_read_trylock(&parent->unreg_sem)) {
287 ret = -ENODEV;
288 goto out_put_device;
289 }
290
291 ret = device_add(&mdev->dev);
292 if (ret)
293 goto out_unlock;
294
295 ret = device_driver_attach(&drv->driver, &mdev->dev);
296 if (ret)
297 goto out_del;
298
299 ret = mdev_create_sysfs_files(mdev);
300 if (ret)
301 goto out_del;
302
303 mdev->active = true;
304 dev_dbg(&mdev->dev, "MDEV: created\n");
305 up_read(&parent->unreg_sem);
306
307 return 0;
308
309 out_del:
310 device_del(&mdev->dev);
311 out_unlock:
312 up_read(&parent->unreg_sem);
313 out_put_device:
314 put_device(&mdev->dev);
315 return ret;
316 }
317
mdev_device_remove(struct mdev_device * mdev)318 int mdev_device_remove(struct mdev_device *mdev)
319 {
320 struct mdev_device *tmp;
321 struct mdev_parent *parent = mdev->type->parent;
322
323 mutex_lock(&mdev_list_lock);
324 list_for_each_entry(tmp, &mdev_list, next) {
325 if (tmp == mdev)
326 break;
327 }
328
329 if (tmp != mdev) {
330 mutex_unlock(&mdev_list_lock);
331 return -ENODEV;
332 }
333
334 if (!mdev->active) {
335 mutex_unlock(&mdev_list_lock);
336 return -EAGAIN;
337 }
338
339 mdev->active = false;
340 mutex_unlock(&mdev_list_lock);
341
342 /* Check if parent unregistration has started */
343 if (!down_read_trylock(&parent->unreg_sem))
344 return -ENODEV;
345
346 mdev_device_remove_common(mdev);
347 up_read(&parent->unreg_sem);
348 return 0;
349 }
350
mdev_init(void)351 static int __init mdev_init(void)
352 {
353 return bus_register(&mdev_bus_type);
354 }
355
mdev_exit(void)356 static void __exit mdev_exit(void)
357 {
358 if (mdev_bus_compat_class)
359 class_compat_unregister(mdev_bus_compat_class);
360 bus_unregister(&mdev_bus_type);
361 }
362
363 subsys_initcall(mdev_init)
364 module_exit(mdev_exit)
365
366 MODULE_VERSION(DRIVER_VERSION);
367 MODULE_LICENSE("GPL v2");
368 MODULE_AUTHOR(DRIVER_AUTHOR);
369 MODULE_DESCRIPTION(DRIVER_DESC);
370