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