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 */
58 struct 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 */
79 struct 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 */
91 enum rpmsg_ns_flags {
92 RPMSG_NS_CREATE = 0,
93 RPMSG_NS_DESTROY = 1,
94 };
95
96 #define RPMSG_ADDR_ANY 0xFFFFFFFF
97
98 struct 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 */
110 struct 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
120 typedef 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 */
145 struct 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 */
162 struct 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
170 int register_rpmsg_device(struct rpmsg_channel *dev);
171 void unregister_rpmsg_device(struct rpmsg_channel *dev);
172 int register_rpmsg_driver(struct rpmsg_driver *drv);
173 void unregister_rpmsg_driver(struct rpmsg_driver *drv);
174 void rpmsg_destroy_ept(struct rpmsg_endpoint *);
175 struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_channel *,
176 rpmsg_rx_cb_t cb, void *priv, u32 addr);
177 int
178 rpmsg_send_offchannel_raw(struct rpmsg_channel *, u32, u32, void *, int, bool);
179
180 /**
181 * rpmsg_send() - send a message across to the remote processor
182 * @rpdev: the rpmsg channel
183 * @data: payload of message
184 * @len: length of payload
185 *
186 * This function sends @data of length @len on the @rpdev channel.
187 * The message will be sent to the remote processor which the @rpdev
188 * channel belongs to, using @rpdev's source and destination addresses.
189 * In case there are no TX buffers available, the function will block until
190 * one becomes available, or a timeout of 15 seconds elapses. When the latter
191 * happens, -ERESTARTSYS is returned.
192 *
193 * Can only be called from process context (for now).
194 *
195 * Returns 0 on success and an appropriate error value on failure.
196 */
rpmsg_send(struct rpmsg_channel * rpdev,void * data,int len)197 static inline int rpmsg_send(struct rpmsg_channel *rpdev, void *data, int len)
198 {
199 u32 src = rpdev->src, dst = rpdev->dst;
200
201 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
202 }
203
204 /**
205 * rpmsg_sendto() - send a message across to the remote processor, specify dst
206 * @rpdev: the rpmsg channel
207 * @data: payload of message
208 * @len: length of payload
209 * @dst: destination address
210 *
211 * This function sends @data of length @len to the remote @dst address.
212 * The message will be sent to the remote processor which the @rpdev
213 * channel belongs to, using @rpdev's source address.
214 * In case there are no TX buffers available, the function will block until
215 * one becomes available, or a timeout of 15 seconds elapses. When the latter
216 * happens, -ERESTARTSYS is returned.
217 *
218 * Can only be called from process context (for now).
219 *
220 * Returns 0 on success and an appropriate error value on failure.
221 */
222 static inline
rpmsg_sendto(struct rpmsg_channel * rpdev,void * data,int len,u32 dst)223 int rpmsg_sendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst)
224 {
225 u32 src = rpdev->src;
226
227 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
228 }
229
230 /**
231 * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
232 * @rpdev: the rpmsg channel
233 * @src: source address
234 * @dst: destination address
235 * @data: payload of message
236 * @len: length of payload
237 *
238 * This function sends @data of length @len to the remote @dst address,
239 * and uses @src as the source address.
240 * The message will be sent to the remote processor which the @rpdev
241 * channel belongs to.
242 * In case there are no TX buffers available, the function will block until
243 * one becomes available, or a timeout of 15 seconds elapses. When the latter
244 * happens, -ERESTARTSYS is returned.
245 *
246 * Can only be called from process context (for now).
247 *
248 * Returns 0 on success and an appropriate error value on failure.
249 */
250 static inline
rpmsg_send_offchannel(struct rpmsg_channel * rpdev,u32 src,u32 dst,void * data,int len)251 int rpmsg_send_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst,
252 void *data, int len)
253 {
254 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
255 }
256
257 /**
258 * rpmsg_send() - send a message across to the remote processor
259 * @rpdev: the rpmsg channel
260 * @data: payload of message
261 * @len: length of payload
262 *
263 * This function sends @data of length @len on the @rpdev channel.
264 * The message will be sent to the remote processor which the @rpdev
265 * channel belongs to, using @rpdev's source and destination addresses.
266 * In case there are no TX buffers available, the function will immediately
267 * return -ENOMEM without waiting until one becomes available.
268 *
269 * Can only be called from process context (for now).
270 *
271 * Returns 0 on success and an appropriate error value on failure.
272 */
273 static inline
rpmsg_trysend(struct rpmsg_channel * rpdev,void * data,int len)274 int rpmsg_trysend(struct rpmsg_channel *rpdev, void *data, int len)
275 {
276 u32 src = rpdev->src, dst = rpdev->dst;
277
278 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
279 }
280
281 /**
282 * rpmsg_sendto() - send a message across to the remote processor, specify dst
283 * @rpdev: the rpmsg channel
284 * @data: payload of message
285 * @len: length of payload
286 * @dst: destination address
287 *
288 * This function sends @data of length @len to the remote @dst address.
289 * The message will be sent to the remote processor which the @rpdev
290 * channel belongs to, using @rpdev's source address.
291 * In case there are no TX buffers available, the function will immediately
292 * return -ENOMEM without waiting until one becomes available.
293 *
294 * Can only be called from process context (for now).
295 *
296 * Returns 0 on success and an appropriate error value on failure.
297 */
298 static inline
rpmsg_trysendto(struct rpmsg_channel * rpdev,void * data,int len,u32 dst)299 int rpmsg_trysendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst)
300 {
301 u32 src = rpdev->src;
302
303 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
304 }
305
306 /**
307 * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
308 * @rpdev: the rpmsg channel
309 * @src: source address
310 * @dst: destination address
311 * @data: payload of message
312 * @len: length of payload
313 *
314 * This function sends @data of length @len to the remote @dst address,
315 * and uses @src as the source address.
316 * The message will be sent to the remote processor which the @rpdev
317 * channel belongs to.
318 * In case there are no TX buffers available, the function will immediately
319 * return -ENOMEM without waiting until one becomes available.
320 *
321 * Can only be called from process context (for now).
322 *
323 * Returns 0 on success and an appropriate error value on failure.
324 */
325 static inline
rpmsg_trysend_offchannel(struct rpmsg_channel * rpdev,u32 src,u32 dst,void * data,int len)326 int rpmsg_trysend_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst,
327 void *data, int len)
328 {
329 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
330 }
331
332 #endif /* _LINUX_RPMSG_H */
333