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