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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
23struct rpmsg_device;
24struct rpmsg_endpoint;
25struct rpmsg_device_ops;
26struct 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 */
34struct 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 * @little_endian: True if transport is using little endian byte representation
50 */
51struct rpmsg_device {
52 struct device dev;
53 struct rpmsg_device_id id;
54 char *driver_override;
55 u32 src;
56 u32 dst;
57 struct rpmsg_endpoint *ept;
58 bool announce;
59 bool little_endian;
60
61 const struct rpmsg_device_ops *ops;
62};
63
64typedef int (*rpmsg_rx_cb_t)(struct rpmsg_device *, void *, int, void *, u32);
65
66/**
67 * struct rpmsg_endpoint - binds a local rpmsg address to its user
68 * @rpdev: rpmsg channel device
69 * @refcount: when this drops to zero, the ept is deallocated
70 * @cb: rx callback handler
71 * @cb_lock: must be taken before accessing/changing @cb
72 * @addr: local rpmsg address
73 * @priv: private data for the driver's use
74 *
75 * In essence, an rpmsg endpoint represents a listener on the rpmsg bus, as
76 * it binds an rpmsg address with an rx callback handler.
77 *
78 * Simple rpmsg drivers shouldn't use this struct directly, because
79 * things just work: every rpmsg driver provides an rx callback upon
80 * registering to the bus, and that callback is then bound to its rpmsg
81 * address when the driver is probed. When relevant inbound messages arrive
82 * (i.e. messages which their dst address equals to the src address of
83 * the rpmsg channel), the driver's handler is invoked to process it.
84 *
85 * More complicated drivers though, that do need to allocate additional rpmsg
86 * addresses, and bind them to different rx callbacks, must explicitly
87 * create additional endpoints by themselves (see rpmsg_create_ept()).
88 */
89struct rpmsg_endpoint {
90 struct rpmsg_device *rpdev;
91 struct kref refcount;
92 rpmsg_rx_cb_t cb;
93 struct mutex cb_lock;
94 u32 addr;
95 void *priv;
96
97 const struct rpmsg_endpoint_ops *ops;
98};
99
100/**
101 * struct rpmsg_driver - rpmsg driver struct
102 * @drv: underlying device driver
103 * @id_table: rpmsg ids serviced by this driver
104 * @probe: invoked when a matching rpmsg channel (i.e. device) is found
105 * @remove: invoked when the rpmsg channel is removed
106 * @callback: invoked when an inbound message is received on the channel
107 */
108struct rpmsg_driver {
109 struct device_driver drv;
110 const struct rpmsg_device_id *id_table;
111 int (*probe)(struct rpmsg_device *dev);
112 void (*remove)(struct rpmsg_device *dev);
113 int (*callback)(struct rpmsg_device *, void *, int, void *, u32);
114};
115
116static inline u16 rpmsg16_to_cpu(struct rpmsg_device *rpdev, __rpmsg16 val)
117{
118 if (!rpdev)
119 return __rpmsg16_to_cpu(rpmsg_is_little_endian(), val);
120 else
121 return __rpmsg16_to_cpu(rpdev->little_endian, val);
122}
123
124static inline __rpmsg16 cpu_to_rpmsg16(struct rpmsg_device *rpdev, u16 val)
125{
126 if (!rpdev)
127 return __cpu_to_rpmsg16(rpmsg_is_little_endian(), val);
128 else
129 return __cpu_to_rpmsg16(rpdev->little_endian, val);
130}
131
132static inline u32 rpmsg32_to_cpu(struct rpmsg_device *rpdev, __rpmsg32 val)
133{
134 if (!rpdev)
135 return __rpmsg32_to_cpu(rpmsg_is_little_endian(), val);
136 else
137 return __rpmsg32_to_cpu(rpdev->little_endian, val);
138}
139
140static inline __rpmsg32 cpu_to_rpmsg32(struct rpmsg_device *rpdev, u32 val)
141{
142 if (!rpdev)
143 return __cpu_to_rpmsg32(rpmsg_is_little_endian(), val);
144 else
145 return __cpu_to_rpmsg32(rpdev->little_endian, val);
146}
147
148static inline u64 rpmsg64_to_cpu(struct rpmsg_device *rpdev, __rpmsg64 val)
149{
150 if (!rpdev)
151 return __rpmsg64_to_cpu(rpmsg_is_little_endian(), val);
152 else
153 return __rpmsg64_to_cpu(rpdev->little_endian, val);
154}
155
156static inline __rpmsg64 cpu_to_rpmsg64(struct rpmsg_device *rpdev, u64 val)
157{
158 if (!rpdev)
159 return __cpu_to_rpmsg64(rpmsg_is_little_endian(), val);
160 else
161 return __cpu_to_rpmsg64(rpdev->little_endian, val);
162}
163
164#if IS_ENABLED(CONFIG_RPMSG)
165
166int rpmsg_register_device(struct rpmsg_device *rpdev);
167int rpmsg_unregister_device(struct device *parent,
168 struct rpmsg_channel_info *chinfo);
169int __register_rpmsg_driver(struct rpmsg_driver *drv, struct module *owner);
170void unregister_rpmsg_driver(struct rpmsg_driver *drv);
171void rpmsg_destroy_ept(struct rpmsg_endpoint *);
172struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *,
173 rpmsg_rx_cb_t cb, void *priv,
174 struct rpmsg_channel_info chinfo);
175
176int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len);
177int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
178int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
179 void *data, int len);
180
181int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len);
182int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
183int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
184 void *data, int len);
185
186__poll_t rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
187 poll_table *wait);
188
189ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept);
190
191#else
192
193static inline int rpmsg_register_device(struct rpmsg_device *rpdev)
194{
195 return -ENXIO;
196}
197
198static inline int rpmsg_unregister_device(struct device *parent,
199 struct rpmsg_channel_info *chinfo)
200{
201 /* This shouldn't be possible */
202 WARN_ON(1);
203
204 return -ENXIO;
205}
206
207static inline int __register_rpmsg_driver(struct rpmsg_driver *drv,
208 struct module *owner)
209{
210 /* This shouldn't be possible */
211 WARN_ON(1);
212
213 return -ENXIO;
214}
215
216static inline void unregister_rpmsg_driver(struct rpmsg_driver *drv)
217{
218 /* This shouldn't be possible */
219 WARN_ON(1);
220}
221
222static inline void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
223{
224 /* This shouldn't be possible */
225 WARN_ON(1);
226}
227
228static inline struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *rpdev,
229 rpmsg_rx_cb_t cb,
230 void *priv,
231 struct rpmsg_channel_info chinfo)
232{
233 /* This shouldn't be possible */
234 WARN_ON(1);
235
236 return NULL;
237}
238
239static inline int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
240{
241 /* This shouldn't be possible */
242 WARN_ON(1);
243
244 return -ENXIO;
245}
246
247static inline int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len,
248 u32 dst)
249{
250 /* This shouldn't be possible */
251 WARN_ON(1);
252
253 return -ENXIO;
254
255}
256
257static inline int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src,
258 u32 dst, void *data, int len)
259{
260 /* This shouldn't be possible */
261 WARN_ON(1);
262
263 return -ENXIO;
264}
265
266static inline int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
267{
268 /* This shouldn't be possible */
269 WARN_ON(1);
270
271 return -ENXIO;
272}
273
274static inline int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
275 int len, u32 dst)
276{
277 /* This shouldn't be possible */
278 WARN_ON(1);
279
280 return -ENXIO;
281}
282
283static inline int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
284 u32 dst, void *data, int len)
285{
286 /* This shouldn't be possible */
287 WARN_ON(1);
288
289 return -ENXIO;
290}
291
292static inline __poll_t rpmsg_poll(struct rpmsg_endpoint *ept,
293 struct file *filp, poll_table *wait)
294{
295 /* This shouldn't be possible */
296 WARN_ON(1);
297
298 return 0;
299}
300
301static inline ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept)
302{
303 /* This shouldn't be possible */
304 WARN_ON(1);
305
306 return -ENXIO;
307}
308
309#endif /* IS_ENABLED(CONFIG_RPMSG) */
310
311/* use a macro to avoid include chaining to get THIS_MODULE */
312#define register_rpmsg_driver(drv) \
313 __register_rpmsg_driver(drv, THIS_MODULE)
314
315/**
316 * module_rpmsg_driver() - Helper macro for registering an rpmsg driver
317 * @__rpmsg_driver: rpmsg_driver struct
318 *
319 * Helper macro for rpmsg drivers which do not do anything special in module
320 * init/exit. This eliminates a lot of boilerplate. Each module may only
321 * use this macro once, and calling it replaces module_init() and module_exit()
322 */
323#define module_rpmsg_driver(__rpmsg_driver) \
324 module_driver(__rpmsg_driver, register_rpmsg_driver, \
325 unregister_rpmsg_driver)
326
327#endif /* _LINUX_RPMSG_H */