xref: /openbmc/linux/include/linux/mdev.h (revision 9c799c22)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Mediated device definition
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 #ifndef MDEV_H
11 #define MDEV_H
12 
13 #include <linux/device.h>
14 #include <linux/uuid.h>
15 
16 struct mdev_type;
17 
18 struct mdev_device {
19 	struct device dev;
20 	guid_t uuid;
21 	struct list_head next;
22 	struct mdev_type *type;
23 	bool active;
24 };
25 
26 struct mdev_type {
27 	/* set by the driver before calling mdev_register parent: */
28 	const char *sysfs_name;
29 	const char *pretty_name;
30 
31 	/* set by the core, can be used drivers */
32 	struct mdev_parent *parent;
33 
34 	/* internal only */
35 	struct kobject kobj;
36 	struct kobject *devices_kobj;
37 };
38 
39 /* embedded into the struct device that the mdev devices hang off */
40 struct mdev_parent {
41 	struct device *dev;
42 	struct mdev_driver *mdev_driver;
43 	struct kset *mdev_types_kset;
44 	/* Synchronize device creation/removal with parent unregistration */
45 	struct rw_semaphore unreg_sem;
46 	struct mdev_type **types;
47 	unsigned int nr_types;
48 	atomic_t available_instances;
49 };
50 
to_mdev_device(struct device * dev)51 static inline struct mdev_device *to_mdev_device(struct device *dev)
52 {
53 	return container_of(dev, struct mdev_device, dev);
54 }
55 
56 /**
57  * struct mdev_driver - Mediated device driver
58  * @device_api: string to return for the device_api sysfs
59  * @max_instances: maximum number of instances supported (optional)
60  * @probe: called when new device created
61  * @remove: called when device removed
62  * @get_available: Return the max number of instances that can be created
63  * @show_description: Print a description of the mtype
64  * @driver: device driver structure
65  **/
66 struct mdev_driver {
67 	const char *device_api;
68 	unsigned int max_instances;
69 	int (*probe)(struct mdev_device *dev);
70 	void (*remove)(struct mdev_device *dev);
71 	unsigned int (*get_available)(struct mdev_type *mtype);
72 	ssize_t (*show_description)(struct mdev_type *mtype, char *buf);
73 	struct device_driver driver;
74 };
75 
76 int mdev_register_parent(struct mdev_parent *parent, struct device *dev,
77 		struct mdev_driver *mdev_driver, struct mdev_type **types,
78 		unsigned int nr_types);
79 void mdev_unregister_parent(struct mdev_parent *parent);
80 
81 int mdev_register_driver(struct mdev_driver *drv);
82 void mdev_unregister_driver(struct mdev_driver *drv);
83 
mdev_dev(struct mdev_device * mdev)84 static inline struct device *mdev_dev(struct mdev_device *mdev)
85 {
86 	return &mdev->dev;
87 }
88 
89 #endif /* MDEV_H */
90