1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Kernel/userspace transport abstraction for Hyper-V util driver.
4  *
5  * Copyright (C) 2015, Vitaly Kuznetsov <vkuznets@redhat.com>
6  */
7 
8 #ifndef _HV_UTILS_TRANSPORT_H
9 #define _HV_UTILS_TRANSPORT_H
10 
11 #include <linux/connector.h>
12 #include <linux/miscdevice.h>
13 
14 enum hvutil_transport_mode {
15 	HVUTIL_TRANSPORT_INIT = 0,
16 	HVUTIL_TRANSPORT_NETLINK,
17 	HVUTIL_TRANSPORT_CHARDEV,
18 	HVUTIL_TRANSPORT_DESTROY,
19 };
20 
21 struct hvutil_transport {
22 	int mode;                           /* hvutil_transport_mode */
23 	struct file_operations fops;        /* file operations */
24 	struct miscdevice mdev;             /* misc device */
25 	struct cb_id cn_id;                 /* CN_*_IDX/CN_*_VAL */
26 	struct list_head list;              /* hvt_list */
27 	int (*on_msg)(void *, int);         /* callback on new user message */
28 	void (*on_reset)(void);             /* callback when userspace drops */
29 	void (*on_read)(void);              /* callback on message read */
30 	u8 *outmsg;                         /* message to the userspace */
31 	int outmsg_len;                     /* its length */
32 	wait_queue_head_t outmsg_q;         /* poll/read wait queue */
33 	struct mutex lock;                  /* protects struct members */
34 	struct completion release;          /* synchronize with fd release */
35 };
36 
37 struct hvutil_transport *hvutil_transport_init(const char *name,
38 					       u32 cn_idx, u32 cn_val,
39 					       int (*on_msg)(void *, int),
40 					       void (*on_reset)(void));
41 int hvutil_transport_send(struct hvutil_transport *hvt, void *msg, int len,
42 			  void (*on_read_cb)(void));
43 void hvutil_transport_destroy(struct hvutil_transport *hvt);
44 
45 #endif /* _HV_UTILS_TRANSPORT_H */
46