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1/*
2 * Remote processor messaging
3 *
4 * Copyright (C) 2011 Texas Instruments, Inc.
5 * Copyright (C) 2011 Google, Inc.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * * Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * * Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in
16 * the documentation and/or other materials provided with the
17 * distribution.
18 * * Neither the name Texas Instruments nor the names of its
19 * contributors may be used to endorse or promote products derived
20 * from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
25 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
26 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
27 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
28 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
32 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 */
34
35#ifndef _LINUX_RPMSG_H
36#define _LINUX_RPMSG_H
37
38#include <linux/types.h>
39#include <linux/device.h>
40#include <linux/mod_devicetable.h>
41#include <linux/kref.h>
42#include <linux/mutex.h>
43
44/* The feature bitmap for virtio rpmsg */
45#define VIRTIO_RPMSG_F_NS 0 /* RP supports name service notifications */
46
47/**
48 * struct rpmsg_hdr - common header for all rpmsg messages
49 * @src: source address
50 * @dst: destination address
51 * @reserved: reserved for future use
52 * @len: length of payload (in bytes)
53 * @flags: message flags
54 * @data: @len bytes of message payload data
55 *
56 * Every message sent(/received) on the rpmsg bus begins with this header.
57 */
58struct rpmsg_hdr {
59 u32 src;
60 u32 dst;
61 u32 reserved;
62 u16 len;
63 u16 flags;
64 u8 data[0];
65} __packed;
66
67/**
68 * struct rpmsg_ns_msg - dynamic name service announcement message
69 * @name: name of remote service that is published
70 * @addr: address of remote service that is published
71 * @flags: indicates whether service is created or destroyed
72 *
73 * This message is sent across to publish a new service, or announce
74 * about its removal. When we receive these messages, an appropriate
75 * rpmsg channel (i.e device) is created/destroyed. In turn, the ->probe()
76 * or ->remove() handler of the appropriate rpmsg driver will be invoked
77 * (if/as-soon-as one is registered).
78 */
79struct rpmsg_ns_msg {
80 char name[RPMSG_NAME_SIZE];
81 u32 addr;
82 u32 flags;
83} __packed;
84
85/**
86 * enum rpmsg_ns_flags - dynamic name service announcement flags
87 *
88 * @RPMSG_NS_CREATE: a new remote service was just created
89 * @RPMSG_NS_DESTROY: a known remote service was just destroyed
90 */
91enum rpmsg_ns_flags {
92 RPMSG_NS_CREATE = 0,
93 RPMSG_NS_DESTROY = 1,
94};
95
96#define RPMSG_ADDR_ANY 0xFFFFFFFF
97
98struct virtproc_info;
99
100/**
101 * rpmsg_channel - devices that belong to the rpmsg bus are called channels
102 * @vrp: the remote processor this channel belongs to
103 * @dev: the device struct
104 * @id: device id (used to match between rpmsg drivers and devices)
105 * @src: local address
106 * @dst: destination address
107 * @ept: the rpmsg endpoint of this channel
108 * @announce: if set, rpmsg will announce the creation/removal of this channel
109 */
110struct rpmsg_channel {
111 struct virtproc_info *vrp;
112 struct device dev;
113 struct rpmsg_device_id id;
114 u32 src;
115 u32 dst;
116 struct rpmsg_endpoint *ept;
117 bool announce;
118};
119
120typedef void (*rpmsg_rx_cb_t)(struct rpmsg_channel *, void *, int, void *, u32);
121
122/**
123 * struct rpmsg_endpoint - binds a local rpmsg address to its user
124 * @rpdev: rpmsg channel device
125 * @refcount: when this drops to zero, the ept is deallocated
126 * @cb: rx callback handler
127 * @cb_lock: must be taken before accessing/changing @cb
128 * @addr: local rpmsg address
129 * @priv: private data for the driver's use
130 *
131 * In essence, an rpmsg endpoint represents a listener on the rpmsg bus, as
132 * it binds an rpmsg address with an rx callback handler.
133 *
134 * Simple rpmsg drivers shouldn't use this struct directly, because
135 * things just work: every rpmsg driver provides an rx callback upon
136 * registering to the bus, and that callback is then bound to its rpmsg
137 * address when the driver is probed. When relevant inbound messages arrive
138 * (i.e. messages which their dst address equals to the src address of
139 * the rpmsg channel), the driver's handler is invoked to process it.
140 *
141 * More complicated drivers though, that do need to allocate additional rpmsg
142 * addresses, and bind them to different rx callbacks, must explicitly
143 * create additional endpoints by themselves (see rpmsg_create_ept()).
144 */
145struct rpmsg_endpoint {
146 struct rpmsg_channel *rpdev;
147 struct kref refcount;
148 rpmsg_rx_cb_t cb;
149 struct mutex cb_lock;
150 u32 addr;
151 void *priv;
152};
153
154/**
155 * struct rpmsg_driver - rpmsg driver struct
156 * @drv: underlying device driver
157 * @id_table: rpmsg ids serviced by this driver
158 * @probe: invoked when a matching rpmsg channel (i.e. device) is found
159 * @remove: invoked when the rpmsg channel is removed
160 * @callback: invoked when an inbound message is received on the channel
161 */
162struct rpmsg_driver {
163 struct device_driver drv;
164 const struct rpmsg_device_id *id_table;
165 int (*probe)(struct rpmsg_channel *dev);
166 void (*remove)(struct rpmsg_channel *dev);
167 void (*callback)(struct rpmsg_channel *, void *, int, void *, u32);
168};
169
170int register_rpmsg_device(struct rpmsg_channel *dev);
171void unregister_rpmsg_device(struct rpmsg_channel *dev);
172int __register_rpmsg_driver(struct rpmsg_driver *drv, struct module *owner);
173void unregister_rpmsg_driver(struct rpmsg_driver *drv);
174void rpmsg_destroy_ept(struct rpmsg_endpoint *);
175struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_channel *,
176 rpmsg_rx_cb_t cb, void *priv, u32 addr);
177int
178rpmsg_send_offchannel_raw(struct rpmsg_channel *, u32, u32, void *, int, bool);
179
180/* use a macro to avoid include chaining to get THIS_MODULE */
181#define register_rpmsg_driver(drv) \
182 __register_rpmsg_driver(drv, THIS_MODULE)
183
184/**
185 * module_rpmsg_driver() - Helper macro for registering an rpmsg driver
186 * @__rpmsg_driver: rpmsg_driver struct
187 *
188 * Helper macro for rpmsg drivers which do not do anything special in module
189 * init/exit. This eliminates a lot of boilerplate. Each module may only
190 * use this macro once, and calling it replaces module_init() and module_exit()
191 */
192#define module_rpmsg_driver(__rpmsg_driver) \
193 module_driver(__rpmsg_driver, register_rpmsg_driver, \
194 unregister_rpmsg_driver)
195
196/**
197 * rpmsg_send() - send a message across to the remote processor
198 * @rpdev: the rpmsg channel
199 * @data: payload of message
200 * @len: length of payload
201 *
202 * This function sends @data of length @len on the @rpdev channel.
203 * The message will be sent to the remote processor which the @rpdev
204 * channel belongs to, using @rpdev's source and destination addresses.
205 * In case there are no TX buffers available, the function will block until
206 * one becomes available, or a timeout of 15 seconds elapses. When the latter
207 * happens, -ERESTARTSYS is returned.
208 *
209 * Can only be called from process context (for now).
210 *
211 * Returns 0 on success and an appropriate error value on failure.
212 */
213static inline int rpmsg_send(struct rpmsg_channel *rpdev, void *data, int len)
214{
215 u32 src = rpdev->src, dst = rpdev->dst;
216
217 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
218}
219
220/**
221 * rpmsg_sendto() - send a message across to the remote processor, specify dst
222 * @rpdev: the rpmsg channel
223 * @data: payload of message
224 * @len: length of payload
225 * @dst: destination address
226 *
227 * This function sends @data of length @len to the remote @dst address.
228 * The message will be sent to the remote processor which the @rpdev
229 * channel belongs to, using @rpdev's source address.
230 * In case there are no TX buffers available, the function will block until
231 * one becomes available, or a timeout of 15 seconds elapses. When the latter
232 * happens, -ERESTARTSYS is returned.
233 *
234 * Can only be called from process context (for now).
235 *
236 * Returns 0 on success and an appropriate error value on failure.
237 */
238static inline
239int rpmsg_sendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst)
240{
241 u32 src = rpdev->src;
242
243 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
244}
245
246/**
247 * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
248 * @rpdev: the rpmsg channel
249 * @src: source address
250 * @dst: destination address
251 * @data: payload of message
252 * @len: length of payload
253 *
254 * This function sends @data of length @len to the remote @dst address,
255 * and uses @src as the source address.
256 * The message will be sent to the remote processor which the @rpdev
257 * channel belongs to.
258 * In case there are no TX buffers available, the function will block until
259 * one becomes available, or a timeout of 15 seconds elapses. When the latter
260 * happens, -ERESTARTSYS is returned.
261 *
262 * Can only be called from process context (for now).
263 *
264 * Returns 0 on success and an appropriate error value on failure.
265 */
266static inline
267int rpmsg_send_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst,
268 void *data, int len)
269{
270 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
271}
272
273/**
274 * rpmsg_send() - send a message across to the remote processor
275 * @rpdev: the rpmsg channel
276 * @data: payload of message
277 * @len: length of payload
278 *
279 * This function sends @data of length @len on the @rpdev channel.
280 * The message will be sent to the remote processor which the @rpdev
281 * channel belongs to, using @rpdev's source and destination addresses.
282 * In case there are no TX buffers available, the function will immediately
283 * return -ENOMEM without waiting until one becomes available.
284 *
285 * Can only be called from process context (for now).
286 *
287 * Returns 0 on success and an appropriate error value on failure.
288 */
289static inline
290int rpmsg_trysend(struct rpmsg_channel *rpdev, void *data, int len)
291{
292 u32 src = rpdev->src, dst = rpdev->dst;
293
294 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
295}
296
297/**
298 * rpmsg_sendto() - send a message across to the remote processor, specify dst
299 * @rpdev: the rpmsg channel
300 * @data: payload of message
301 * @len: length of payload
302 * @dst: destination address
303 *
304 * This function sends @data of length @len to the remote @dst address.
305 * The message will be sent to the remote processor which the @rpdev
306 * channel belongs to, using @rpdev's source address.
307 * In case there are no TX buffers available, the function will immediately
308 * return -ENOMEM without waiting until one becomes available.
309 *
310 * Can only be called from process context (for now).
311 *
312 * Returns 0 on success and an appropriate error value on failure.
313 */
314static inline
315int rpmsg_trysendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst)
316{
317 u32 src = rpdev->src;
318
319 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
320}
321
322/**
323 * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
324 * @rpdev: the rpmsg channel
325 * @src: source address
326 * @dst: destination address
327 * @data: payload of message
328 * @len: length of payload
329 *
330 * This function sends @data of length @len to the remote @dst address,
331 * and uses @src as the source address.
332 * The message will be sent to the remote processor which the @rpdev
333 * channel belongs to.
334 * In case there are no TX buffers available, the function will immediately
335 * return -ENOMEM without waiting until one becomes available.
336 *
337 * Can only be called from process context (for now).
338 *
339 * Returns 0 on success and an appropriate error value on failure.
340 */
341static inline
342int rpmsg_trysend_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst,
343 void *data, int len)
344{
345 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
346}
347
348#endif /* _LINUX_RPMSG_H */