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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; 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 */
53struct 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
66typedef int (*rpmsg_rx_cb_t)(struct rpmsg_device *, void *, int, void *, u32);
67typedef 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 */
93struct 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 */
114struct 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
123static 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
131static 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
139static 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
147static 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
155static 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
163static 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
173int rpmsg_register_device_override(struct rpmsg_device *rpdev,
174 const char *driver_override);
175int rpmsg_register_device(struct rpmsg_device *rpdev);
176int rpmsg_unregister_device(struct device *parent,
177 struct rpmsg_channel_info *chinfo);
178int __register_rpmsg_driver(struct rpmsg_driver *drv, struct module *owner);
179void unregister_rpmsg_driver(struct rpmsg_driver *drv);
180void rpmsg_destroy_ept(struct rpmsg_endpoint *);
181struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *,
182 rpmsg_rx_cb_t cb, void *priv,
183 struct rpmsg_channel_info chinfo);
184
185int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len);
186int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
187
188int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len);
189int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
190
191__poll_t rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
192 poll_table *wait);
193
194ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept);
195
196int rpmsg_set_flow_control(struct rpmsg_endpoint *ept, bool pause, u32 dst);
197
198#else
199
200static inline int rpmsg_register_device_override(struct rpmsg_device *rpdev,
201 const char *driver_override)
202{
203 return -ENXIO;
204}
205
206static inline int rpmsg_register_device(struct rpmsg_device *rpdev)
207{
208 return -ENXIO;
209}
210
211static inline int rpmsg_unregister_device(struct device *parent,
212 struct rpmsg_channel_info *chinfo)
213{
214 /* This shouldn't be possible */
215 WARN_ON(1);
216
217 return -ENXIO;
218}
219
220static inline int __register_rpmsg_driver(struct rpmsg_driver *drv,
221 struct module *owner)
222{
223 /* This shouldn't be possible */
224 WARN_ON(1);
225
226 return -ENXIO;
227}
228
229static inline void unregister_rpmsg_driver(struct rpmsg_driver *drv)
230{
231 /* This shouldn't be possible */
232 WARN_ON(1);
233}
234
235static inline void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
236{
237 /* This shouldn't be possible */
238 WARN_ON(1);
239}
240
241static inline struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *rpdev,
242 rpmsg_rx_cb_t cb,
243 void *priv,
244 struct rpmsg_channel_info chinfo)
245{
246 /* This shouldn't be possible */
247 WARN_ON(1);
248
249 return NULL;
250}
251
252static inline int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
253{
254 /* This shouldn't be possible */
255 WARN_ON(1);
256
257 return -ENXIO;
258}
259
260static inline int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len,
261 u32 dst)
262{
263 /* This shouldn't be possible */
264 WARN_ON(1);
265
266 return -ENXIO;
267
268}
269
270static inline int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
271{
272 /* This shouldn't be possible */
273 WARN_ON(1);
274
275 return -ENXIO;
276}
277
278static inline int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
279 int len, u32 dst)
280{
281 /* This shouldn't be possible */
282 WARN_ON(1);
283
284 return -ENXIO;
285}
286
287static inline __poll_t rpmsg_poll(struct rpmsg_endpoint *ept,
288 struct file *filp, poll_table *wait)
289{
290 /* This shouldn't be possible */
291 WARN_ON(1);
292
293 return 0;
294}
295
296static inline ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept)
297{
298 /* This shouldn't be possible */
299 WARN_ON(1);
300
301 return -ENXIO;
302}
303
304static inline int rpmsg_set_flow_control(struct rpmsg_endpoint *ept, bool pause, u32 dst)
305{
306 /* This shouldn't be possible */
307 WARN_ON(1);
308
309 return -ENXIO;
310}
311
312#endif /* IS_ENABLED(CONFIG_RPMSG) */
313
314/* use a macro to avoid include chaining to get THIS_MODULE */
315#define register_rpmsg_driver(drv) \
316 __register_rpmsg_driver(drv, THIS_MODULE)
317
318/**
319 * module_rpmsg_driver() - Helper macro for registering an rpmsg driver
320 * @__rpmsg_driver: rpmsg_driver struct
321 *
322 * Helper macro for rpmsg drivers which do not do anything special in module
323 * init/exit. This eliminates a lot of boilerplate. Each module may only
324 * use this macro once, and calling it replaces module_init() and module_exit()
325 */
326#define module_rpmsg_driver(__rpmsg_driver) \
327 module_driver(__rpmsg_driver, register_rpmsg_driver, \
328 unregister_rpmsg_driver)
329
330#endif /* _LINUX_RPMSG_H */