1 /* SPDX-License-Identifier: BSD-3-Clause */
2 /*
3  * Remote processor messaging
4  *
5  * Copyright (C) 2011 Texas Instruments, Inc.
6  * Copyright (C) 2011 Google, Inc.
7  * All rights reserved.
8  */
9 
10 #ifndef _LINUX_RPMSG_H
11 #define _LINUX_RPMSG_H
12 
13 #include <linux/types.h>
14 #include <linux/device.h>
15 #include <linux/err.h>
16 #include <linux/mod_devicetable.h>
17 #include <linux/kref.h>
18 #include <linux/mutex.h>
19 #include <linux/poll.h>
20 
21 #define RPMSG_ADDR_ANY		0xFFFFFFFF
22 
23 struct rpmsg_device;
24 struct rpmsg_endpoint;
25 struct rpmsg_device_ops;
26 struct rpmsg_endpoint_ops;
27 
28 /**
29  * struct rpmsg_channel_info - channel info representation
30  * @name: name of service
31  * @src: local address
32  * @dst: destination address
33  */
34 struct rpmsg_channel_info {
35 	char name[RPMSG_NAME_SIZE];
36 	u32 src;
37 	u32 dst;
38 };
39 
40 /**
41  * rpmsg_device - device that belong to the rpmsg bus
42  * @dev: the device struct
43  * @id: device id (used to match between rpmsg drivers and devices)
44  * @driver_override: driver name to force a match
45  * @src: local address
46  * @dst: destination address
47  * @ept: the rpmsg endpoint of this channel
48  * @announce: if set, rpmsg will announce the creation/removal of this channel
49  */
50 struct rpmsg_device {
51 	struct device dev;
52 	struct rpmsg_device_id id;
53 	char *driver_override;
54 	u32 src;
55 	u32 dst;
56 	struct rpmsg_endpoint *ept;
57 	bool announce;
58 
59 	const struct rpmsg_device_ops *ops;
60 };
61 
62 typedef int (*rpmsg_rx_cb_t)(struct rpmsg_device *, void *, int, void *, u32);
63 
64 /**
65  * struct rpmsg_endpoint - binds a local rpmsg address to its user
66  * @rpdev: rpmsg channel device
67  * @refcount: when this drops to zero, the ept is deallocated
68  * @cb: rx callback handler
69  * @cb_lock: must be taken before accessing/changing @cb
70  * @addr: local rpmsg address
71  * @priv: private data for the driver's use
72  *
73  * In essence, an rpmsg endpoint represents a listener on the rpmsg bus, as
74  * it binds an rpmsg address with an rx callback handler.
75  *
76  * Simple rpmsg drivers shouldn't use this struct directly, because
77  * things just work: every rpmsg driver provides an rx callback upon
78  * registering to the bus, and that callback is then bound to its rpmsg
79  * address when the driver is probed. When relevant inbound messages arrive
80  * (i.e. messages which their dst address equals to the src address of
81  * the rpmsg channel), the driver's handler is invoked to process it.
82  *
83  * More complicated drivers though, that do need to allocate additional rpmsg
84  * addresses, and bind them to different rx callbacks, must explicitly
85  * create additional endpoints by themselves (see rpmsg_create_ept()).
86  */
87 struct rpmsg_endpoint {
88 	struct rpmsg_device *rpdev;
89 	struct kref refcount;
90 	rpmsg_rx_cb_t cb;
91 	struct mutex cb_lock;
92 	u32 addr;
93 	void *priv;
94 
95 	const struct rpmsg_endpoint_ops *ops;
96 };
97 
98 /**
99  * struct rpmsg_driver - rpmsg driver struct
100  * @drv: underlying device driver
101  * @id_table: rpmsg ids serviced by this driver
102  * @probe: invoked when a matching rpmsg channel (i.e. device) is found
103  * @remove: invoked when the rpmsg channel is removed
104  * @callback: invoked when an inbound message is received on the channel
105  */
106 struct rpmsg_driver {
107 	struct device_driver drv;
108 	const struct rpmsg_device_id *id_table;
109 	int (*probe)(struct rpmsg_device *dev);
110 	void (*remove)(struct rpmsg_device *dev);
111 	int (*callback)(struct rpmsg_device *, void *, int, void *, u32);
112 };
113 
114 #if IS_ENABLED(CONFIG_RPMSG)
115 
116 int register_rpmsg_device(struct rpmsg_device *dev);
117 void unregister_rpmsg_device(struct rpmsg_device *dev);
118 int __register_rpmsg_driver(struct rpmsg_driver *drv, struct module *owner);
119 void unregister_rpmsg_driver(struct rpmsg_driver *drv);
120 void rpmsg_destroy_ept(struct rpmsg_endpoint *);
121 struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *,
122 					rpmsg_rx_cb_t cb, void *priv,
123 					struct rpmsg_channel_info chinfo);
124 
125 int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len);
126 int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
127 int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
128 			  void *data, int len);
129 
130 int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len);
131 int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
132 int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
133 			     void *data, int len);
134 
135 __poll_t rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
136 			poll_table *wait);
137 
138 #else
139 
register_rpmsg_device(struct rpmsg_device * dev)140 static inline int register_rpmsg_device(struct rpmsg_device *dev)
141 {
142 	return -ENXIO;
143 }
144 
unregister_rpmsg_device(struct rpmsg_device * dev)145 static inline void unregister_rpmsg_device(struct rpmsg_device *dev)
146 {
147 	/* This shouldn't be possible */
148 	WARN_ON(1);
149 }
150 
__register_rpmsg_driver(struct rpmsg_driver * drv,struct module * owner)151 static inline int __register_rpmsg_driver(struct rpmsg_driver *drv,
152 					  struct module *owner)
153 {
154 	/* This shouldn't be possible */
155 	WARN_ON(1);
156 
157 	return -ENXIO;
158 }
159 
unregister_rpmsg_driver(struct rpmsg_driver * drv)160 static inline void unregister_rpmsg_driver(struct rpmsg_driver *drv)
161 {
162 	/* This shouldn't be possible */
163 	WARN_ON(1);
164 }
165 
rpmsg_destroy_ept(struct rpmsg_endpoint * ept)166 static inline void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
167 {
168 	/* This shouldn't be possible */
169 	WARN_ON(1);
170 }
171 
rpmsg_create_ept(struct rpmsg_device * rpdev,rpmsg_rx_cb_t cb,void * priv,struct rpmsg_channel_info chinfo)172 static inline struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *rpdev,
173 						      rpmsg_rx_cb_t cb,
174 						      void *priv,
175 						      struct rpmsg_channel_info chinfo)
176 {
177 	/* This shouldn't be possible */
178 	WARN_ON(1);
179 
180 	return NULL;
181 }
182 
rpmsg_send(struct rpmsg_endpoint * ept,void * data,int len)183 static inline int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
184 {
185 	/* This shouldn't be possible */
186 	WARN_ON(1);
187 
188 	return -ENXIO;
189 }
190 
rpmsg_sendto(struct rpmsg_endpoint * ept,void * data,int len,u32 dst)191 static inline int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len,
192 			       u32 dst)
193 {
194 	/* This shouldn't be possible */
195 	WARN_ON(1);
196 
197 	return -ENXIO;
198 
199 }
200 
rpmsg_send_offchannel(struct rpmsg_endpoint * ept,u32 src,u32 dst,void * data,int len)201 static inline int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src,
202 					u32 dst, void *data, int len)
203 {
204 	/* This shouldn't be possible */
205 	WARN_ON(1);
206 
207 	return -ENXIO;
208 }
209 
rpmsg_trysend(struct rpmsg_endpoint * ept,void * data,int len)210 static inline int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
211 {
212 	/* This shouldn't be possible */
213 	WARN_ON(1);
214 
215 	return -ENXIO;
216 }
217 
rpmsg_trysendto(struct rpmsg_endpoint * ept,void * data,int len,u32 dst)218 static inline int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
219 				  int len, u32 dst)
220 {
221 	/* This shouldn't be possible */
222 	WARN_ON(1);
223 
224 	return -ENXIO;
225 }
226 
rpmsg_trysend_offchannel(struct rpmsg_endpoint * ept,u32 src,u32 dst,void * data,int len)227 static inline int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
228 					   u32 dst, void *data, int len)
229 {
230 	/* This shouldn't be possible */
231 	WARN_ON(1);
232 
233 	return -ENXIO;
234 }
235 
rpmsg_poll(struct rpmsg_endpoint * ept,struct file * filp,poll_table * wait)236 static inline __poll_t rpmsg_poll(struct rpmsg_endpoint *ept,
237 				      struct file *filp, poll_table *wait)
238 {
239 	/* This shouldn't be possible */
240 	WARN_ON(1);
241 
242 	return 0;
243 }
244 
245 #endif /* IS_ENABLED(CONFIG_RPMSG) */
246 
247 /* use a macro to avoid include chaining to get THIS_MODULE */
248 #define register_rpmsg_driver(drv) \
249 	__register_rpmsg_driver(drv, THIS_MODULE)
250 
251 /**
252  * module_rpmsg_driver() - Helper macro for registering an rpmsg driver
253  * @__rpmsg_driver: rpmsg_driver struct
254  *
255  * Helper macro for rpmsg drivers which do not do anything special in module
256  * init/exit. This eliminates a lot of boilerplate.  Each module may only
257  * use this macro once, and calling it replaces module_init() and module_exit()
258  */
259 #define module_rpmsg_driver(__rpmsg_driver) \
260 	module_driver(__rpmsg_driver, register_rpmsg_driver, \
261 			unregister_rpmsg_driver)
262 
263 #endif /* _LINUX_RPMSG_H */
264