include/linux/rpmsg.h

   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 #define RPMSG_ADDR_ANY          0xFFFFFFFF
  45
  46 struct rpmsg_device;
  47 struct rpmsg_endpoint;
  48 struct rpmsg_device_ops;
  49 struct rpmsg_endpoint_ops;
  50
  51 /**
  52  * struct rpmsg_channel_info - channel info representation
  53  * @name: name of service
  54  * @src: local address
  55  * @dst: destination address
  56  */
  57 struct rpmsg_channel_info {
  58         char name[RPMSG_NAME_SIZE];
  59         u32 src;
  60         u32 dst;
  61 };
  62
  63 /**
  64  * rpmsg_device - device that belong to the rpmsg bus
  65  * @dev: the device struct
  66  * @id: device id (used to match between rpmsg drivers and devices)
  67  * @src: local address
  68  * @dst: destination address
  69  * @ept: the rpmsg endpoint of this channel
  70  * @announce: if set, rpmsg will announce the creation/removal of this channel
  71  */
  72 struct rpmsg_device {
  73         struct device dev;
  74         struct rpmsg_device_id id;
  75         u32 src;
  76         u32 dst;
  77         struct rpmsg_endpoint *ept;
  78         bool announce;
  79
  80         const struct rpmsg_device_ops *ops;
  81 };
  82
  83 typedef int (*rpmsg_rx_cb_t)(struct rpmsg_device *, void *, int, void *, u32);
  84
  85 /**
  86  * struct rpmsg_endpoint - binds a local rpmsg address to its user
  87  * @rpdev: rpmsg channel device
  88  * @refcount: when this drops to zero, the ept is deallocated
  89  * @cb: rx callback handler
  90  * @cb_lock: must be taken before accessing/changing @cb
  91  * @addr: local rpmsg address
  92  * @priv: private data for the driver's use
  93  *
  94  * In essence, an rpmsg endpoint represents a listener on the rpmsg bus, as
  95  * it binds an rpmsg address with an rx callback handler.
  96  *
  97  * Simple rpmsg drivers shouldn't use this struct directly, because
  98  * things just work: every rpmsg driver provides an rx callback upon
  99  * registering to the bus, and that callback is then bound to its rpmsg
 100  * address when the driver is probed. When relevant inbound messages arrive
 101  * (i.e. messages which their dst address equals to the src address of
 102  * the rpmsg channel), the driver's handler is invoked to process it.
 103  *
 104  * More complicated drivers though, that do need to allocate additional rpmsg
 105  * addresses, and bind them to different rx callbacks, must explicitly
 106  * create additional endpoints by themselves (see rpmsg_create_ept()).
 107  */
 108 struct rpmsg_endpoint {
 109         struct rpmsg_device *rpdev;
 110         struct kref refcount;
 111         rpmsg_rx_cb_t cb;
 112         struct mutex cb_lock;
 113         u32 addr;
 114         void *priv;
 115
 116         const struct rpmsg_endpoint_ops *ops;
 117 };
 118
 119 /**
 120  * struct rpmsg_driver - rpmsg driver struct
 121  * @drv: underlying device driver
 122  * @id_table: rpmsg ids serviced by this driver
 123  * @probe: invoked when a matching rpmsg channel (i.e. device) is found
 124  * @remove: invoked when the rpmsg channel is removed
 125  * @callback: invoked when an inbound message is received on the channel
 126  */
 127 struct rpmsg_driver {
 128         struct device_driver drv;
 129         const struct rpmsg_device_id *id_table;
 130         int (*probe)(struct rpmsg_device *dev);
 131         void (*remove)(struct rpmsg_device *dev);
 132         int (*callback)(struct rpmsg_device *, void *, int, void *, u32);
 133 };
 134
 135 int register_rpmsg_device(struct rpmsg_device *dev);
 136 void unregister_rpmsg_device(struct rpmsg_device *dev);
 137 int __register_rpmsg_driver(struct rpmsg_driver *drv, struct module *owner);
 138 void unregister_rpmsg_driver(struct rpmsg_driver *drv);
 139 void rpmsg_destroy_ept(struct rpmsg_endpoint *);
 140 struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *,
 141                                         rpmsg_rx_cb_t cb, void *priv,
 142                                         struct rpmsg_channel_info chinfo);
 143
 144 /* use a macro to avoid include chaining to get THIS_MODULE */
 145 #define register_rpmsg_driver(drv) \
 146         __register_rpmsg_driver(drv, THIS_MODULE)
 147
 148 /**
 149  * module_rpmsg_driver() - Helper macro for registering an rpmsg driver
 150  * @__rpmsg_driver: rpmsg_driver struct
 151  *
 152  * Helper macro for rpmsg drivers which do not do anything special in module
 153  * init/exit. This eliminates a lot of boilerplate.  Each module may only
 154  * use this macro once, and calling it replaces module_init() and module_exit()
 155  */
 156 #define module_rpmsg_driver(__rpmsg_driver) \
 157         module_driver(__rpmsg_driver, register_rpmsg_driver, \
 158                         unregister_rpmsg_driver)
 159
 160 int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len);
 161 int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
 162 int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 163                           void *data, int len);
 164
 165 int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len);
 166 int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
 167 int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 168                              void *data, int len);
 169
 170 #endif /* _LINUX_RPMSG_H */