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 #include <linux/rpmsg/byteorder.h>
21 #include <uapi/linux/rpmsg.h>
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; do not set directly,
45 * because core frees it; use driver_set_override() to
46 * set or clear it.
47 * @src: local address
48 * @dst: destination address
49 * @ept: the rpmsg endpoint of this channel
50 * @announce: if set, rpmsg will announce the creation/removal of this channel
51 * @little_endian: True if transport is using little endian byte representation
52 */
53 struct rpmsg_device {
54 struct device dev;
55 struct rpmsg_device_id id;
56 const char *driver_override;
57 u32 src;
58 u32 dst;
59 struct rpmsg_endpoint *ept;
60 bool announce;
61 bool little_endian;
62
63 const struct rpmsg_device_ops *ops;
64 };
65
66 typedef int (*rpmsg_rx_cb_t)(struct rpmsg_device *, void *, int, void *, u32);
67 typedef int (*rpmsg_flowcontrol_cb_t)(struct rpmsg_device *, void *, bool);
68
69 /**
70 * struct rpmsg_endpoint - binds a local rpmsg address to its user
71 * @rpdev: rpmsg channel device
72 * @refcount: when this drops to zero, the ept is deallocated
73 * @cb: rx callback handler
74 * @flow_cb: remote flow control callback handler
75 * @cb_lock: must be taken before accessing/changing @cb
76 * @addr: local rpmsg address
77 * @priv: private data for the driver's use
78 *
79 * In essence, an rpmsg endpoint represents a listener on the rpmsg bus, as
80 * it binds an rpmsg address with an rx callback handler.
81 *
82 * Simple rpmsg drivers shouldn't use this struct directly, because
83 * things just work: every rpmsg driver provides an rx callback upon
84 * registering to the bus, and that callback is then bound to its rpmsg
85 * address when the driver is probed. When relevant inbound messages arrive
86 * (i.e. messages which their dst address equals to the src address of
87 * the rpmsg channel), the driver's handler is invoked to process it.
88 *
89 * More complicated drivers though, that do need to allocate additional rpmsg
90 * addresses, and bind them to different rx callbacks, must explicitly
91 * create additional endpoints by themselves (see rpmsg_create_ept()).
92 */
93 struct rpmsg_endpoint {
94 struct rpmsg_device *rpdev;
95 struct kref refcount;
96 rpmsg_rx_cb_t cb;
97 rpmsg_flowcontrol_cb_t flow_cb;
98 struct mutex cb_lock;
99 u32 addr;
100 void *priv;
101
102 const struct rpmsg_endpoint_ops *ops;
103 };
104
105 /**
106 * struct rpmsg_driver - rpmsg driver struct
107 * @drv: underlying device driver
108 * @id_table: rpmsg ids serviced by this driver
109 * @probe: invoked when a matching rpmsg channel (i.e. device) is found
110 * @remove: invoked when the rpmsg channel is removed
111 * @callback: invoked when an inbound message is received on the channel
112 * @flowcontrol: invoked when remote side flow control request is received
113 */
114 struct rpmsg_driver {
115 struct device_driver drv;
116 const struct rpmsg_device_id *id_table;
117 int (*probe)(struct rpmsg_device *dev);
118 void (*remove)(struct rpmsg_device *dev);
119 int (*callback)(struct rpmsg_device *, void *, int, void *, u32);
120 int (*flowcontrol)(struct rpmsg_device *, void *, bool);
121 };
122
123 static inline u16 rpmsg16_to_cpu(struct rpmsg_device *rpdev, __rpmsg16 val)
124 {
125 if (!rpdev)
126 return __rpmsg16_to_cpu(rpmsg_is_little_endian(), val);
127 else
128 return __rpmsg16_to_cpu(rpdev->little_endian, val);
129 }
130
131 static inline __rpmsg16 cpu_to_rpmsg16(struct rpmsg_device *rpdev, u16 val)
132 {
133 if (!rpdev)
134 return __cpu_to_rpmsg16(rpmsg_is_little_endian(), val);
135 else
136 return __cpu_to_rpmsg16(rpdev->little_endian, val);
137 }
138
139 static inline u32 rpmsg32_to_cpu(struct rpmsg_device *rpdev, __rpmsg32 val)
140 {
141 if (!rpdev)
142 return __rpmsg32_to_cpu(rpmsg_is_little_endian(), val);
143 else
144 return __rpmsg32_to_cpu(rpdev->little_endian, val);
145 }
146
147 static inline __rpmsg32 cpu_to_rpmsg32(struct rpmsg_device *rpdev, u32 val)
148 {
149 if (!rpdev)
150 return __cpu_to_rpmsg32(rpmsg_is_little_endian(), val);
151 else
152 return __cpu_to_rpmsg32(rpdev->little_endian, val);
153 }
154
155 static inline u64 rpmsg64_to_cpu(struct rpmsg_device *rpdev, __rpmsg64 val)
156 {
157 if (!rpdev)
158 return __rpmsg64_to_cpu(rpmsg_is_little_endian(), val);
159 else
160 return __rpmsg64_to_cpu(rpdev->little_endian, val);
161 }
162
163 static inline __rpmsg64 cpu_to_rpmsg64(struct rpmsg_device *rpdev, u64 val)
164 {
165 if (!rpdev)
166 return __cpu_to_rpmsg64(rpmsg_is_little_endian(), val);
167 else
168 return __cpu_to_rpmsg64(rpdev->little_endian, val);
169 }
170
171 #if IS_ENABLED(CONFIG_RPMSG)
172
173 int rpmsg_register_device_override(struct rpmsg_device *rpdev,
174 const char *driver_override);
175 int rpmsg_register_device(struct rpmsg_device *rpdev);
176 int rpmsg_unregister_device(struct device *parent,
177 struct rpmsg_channel_info *chinfo);
178 int __register_rpmsg_driver(struct rpmsg_driver *drv, struct module *owner);
179 void unregister_rpmsg_driver(struct rpmsg_driver *drv);
180 void rpmsg_destroy_ept(struct rpmsg_endpoint *);
181 struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *,
182 rpmsg_rx_cb_t cb, void *priv,
183 struct rpmsg_channel_info chinfo);
184
185 int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len);
186 int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
187 int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
188 void *data, int len);
189
190 int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len);
191 int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
192 int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
193 void *data, int len);
194
195 __poll_t rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
196 poll_table *wait);
197
198 ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept);
199
200 int rpmsg_set_flow_control(struct rpmsg_endpoint *ept, bool pause, u32 dst);
201
202 #else
203
204 static inline int rpmsg_register_device_override(struct rpmsg_device *rpdev,
205 const char *driver_override)
206 {
207 return -ENXIO;
208 }
209
210 static inline int rpmsg_register_device(struct rpmsg_device *rpdev)
211 {
212 return -ENXIO;
213 }
214
215 static inline int rpmsg_unregister_device(struct device *parent,
216 struct rpmsg_channel_info *chinfo)
217 {
218 /* This shouldn't be possible */
219 WARN_ON(1);
220
221 return -ENXIO;
222 }
223
224 static inline int __register_rpmsg_driver(struct rpmsg_driver *drv,
225 struct module *owner)
226 {
227 /* This shouldn't be possible */
228 WARN_ON(1);
229
230 return -ENXIO;
231 }
232
233 static inline void unregister_rpmsg_driver(struct rpmsg_driver *drv)
234 {
235 /* This shouldn't be possible */
236 WARN_ON(1);
237 }
238
239 static inline void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
240 {
241 /* This shouldn't be possible */
242 WARN_ON(1);
243 }
244
245 static inline struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *rpdev,
246 rpmsg_rx_cb_t cb,
247 void *priv,
248 struct rpmsg_channel_info chinfo)
249 {
250 /* This shouldn't be possible */
251 WARN_ON(1);
252
253 return NULL;
254 }
255
256 static inline int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
257 {
258 /* This shouldn't be possible */
259 WARN_ON(1);
260
261 return -ENXIO;
262 }
263
264 static inline int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len,
265 u32 dst)
266 {
267 /* This shouldn't be possible */
268 WARN_ON(1);
269
270 return -ENXIO;
271
272 }
273
274 static inline int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src,
275 u32 dst, void *data, int len)
276 {
277 /* This shouldn't be possible */
278 WARN_ON(1);
279
280 return -ENXIO;
281 }
282
283 static inline int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
284 {
285 /* This shouldn't be possible */
286 WARN_ON(1);
287
288 return -ENXIO;
289 }
290
291 static inline int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
292 int len, u32 dst)
293 {
294 /* This shouldn't be possible */
295 WARN_ON(1);
296
297 return -ENXIO;
298 }
299
300 static inline int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
301 u32 dst, void *data, int len)
302 {
303 /* This shouldn't be possible */
304 WARN_ON(1);
305
306 return -ENXIO;
307 }
308
309 static inline __poll_t rpmsg_poll(struct rpmsg_endpoint *ept,
310 struct file *filp, poll_table *wait)
311 {
312 /* This shouldn't be possible */
313 WARN_ON(1);
314
315 return 0;
316 }
317
318 static inline ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept)
319 {
320 /* This shouldn't be possible */
321 WARN_ON(1);
322
323 return -ENXIO;
324 }
325
326 static inline int rpmsg_set_flow_control(struct rpmsg_endpoint *ept, bool pause, u32 dst)
327 {
328 /* This shouldn't be possible */
329 WARN_ON(1);
330
331 return -ENXIO;
332 }
333
334 #endif /* IS_ENABLED(CONFIG_RPMSG) */
335
336 /* use a macro to avoid include chaining to get THIS_MODULE */
337 #define register_rpmsg_driver(drv) \
338 __register_rpmsg_driver(drv, THIS_MODULE)
339
340 /**
341 * module_rpmsg_driver() - Helper macro for registering an rpmsg driver
342 * @__rpmsg_driver: rpmsg_driver struct
343 *
344 * Helper macro for rpmsg drivers which do not do anything special in module
345 * init/exit. This eliminates a lot of boilerplate. Each module may only
346 * use this macro once, and calling it replaces module_init() and module_exit()
347 */
348 #define module_rpmsg_driver(__rpmsg_driver) \
349 module_driver(__rpmsg_driver, register_rpmsg_driver, \
350 unregister_rpmsg_driver)
351
352 #endif /* _LINUX_RPMSG_H */
353
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