rpmsg: add api for creating and deleting rpmsg channels

The rpmsg channels are currently created and deleted only through
the device announcements from a remote processor. Two new exported
functions, rpmsg_create_channel and rpmsg_destroy_channel, are added
to be able to create and delete a rpmsg channel on a particular
virtual processor.

This is required for creating/deleting a channel from the HLOS-side
(needed by the rpmsg socket driver).

Signed-off-by: Robert Tivy <rtivy@ti.com>
[s-anna@ti.com: add delete channel api and documentation]
Signed-off-by: Suman Anna <s-anna@ti.com>

2 files changed, 70 insertions, 6 deletions

diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
index b142a0e5e4f..4ce5f43a54a 100644
--- a/drivers/rpmsg/virtio_rpmsg_bus.c
+++ b/drivers/rpmsg/virtio_rpmsg_bus.c
@@ -502,7 +502,7 @@ static int rpmsg_channel_match(struct device *dev, void *data)
  * this function will be used to create both static and dynamic
  * channels.
  */
-static struct rpmsg_channel *rpmsg_create_channel(struct virtproc_info *vrp,
+static struct rpmsg_channel *__rpmsg_create_channel(struct virtproc_info *vrp,
                                 struct rpmsg_channel_info *chinfo)
 {
         struct rpmsg_channel *rpdev;
@@ -556,11 +556,42 @@ static struct rpmsg_channel *rpmsg_create_channel(struct virtproc_info *vrp,
         return rpdev;
 }
 
+/**
+ * rpmsg_create_channel - create a rpmsg channel using its name, desc, id and
+ *                        address
+ * @vrp: the virtual processor on which this channel is being created
+ * @name: name of the rpmsg channel
+ * @desc: description of the rpmsg channel
+ * @src: source end-point address for the channel
+ * @dst: destination end-point address for the channel
+ *
+ * This function provides a means to create new rpmsg channels on a particular
+ * virtual processor. The caller supplies the address info, name and descriptor
+ * for the channel. This is useful when creating channels from the host side.
+ *
+ * Return: a pointer to a newly created rpmsg channel device on success,
+ *         or NULL on failure
+ */
+struct rpmsg_channel *rpmsg_create_channel(struct virtproc_info *vrp,
+                                           const char *name, const char *desc,
+                                           int src, int dst)
+{
+        struct rpmsg_channel_info chinfo;
+
+        strncpy(chinfo.name, name, sizeof(chinfo.name));
+        strncpy(chinfo.desc, desc, sizeof(chinfo.desc));
+        chinfo.src = src;
+        chinfo.dst = dst;
+
+        return __rpmsg_create_channel(vrp, &chinfo);
+}
+EXPORT_SYMBOL(rpmsg_create_channel);
+
 /*
  * find an existing channel using its name + address properties,
  * and destroy it
  */
-static int rpmsg_destroy_channel(struct virtproc_info *vrp,
+static int __rpmsg_destroy_channel(struct virtproc_info *vrp,
                                         struct rpmsg_channel_info *chinfo)
 {
         struct virtio_device *vdev = vrp->vdev;
@@ -577,6 +608,34 @@ static int rpmsg_destroy_channel(struct virtproc_info *vrp,
         return 0;
 }
 
+/**
+ * rpmsg_destroy_channel - destroy a rpmsg channel
+ * @rpdev: rpmsg channel to be destroyed
+ *
+ * This function is the primary means to destroy a rpmsg channel that was
+ * created from the host-side. This API is strictly intended to be used only
+ * for channels created using the rpmsg_create_channel API.
+ *
+ * Return: 0 on success, or a failure code otherwise
+ */
+int rpmsg_destroy_channel(struct rpmsg_channel *rpdev)
+{
+        struct device *dev;
+        struct virtio_device *vdev = rpmsg_get_virtio_dev(rpdev);
+
+        if (!rpdev || !vdev)
+                return -EINVAL;
+
+        dev = &rpdev->dev;
+        if (dev->bus != &rpmsg_bus || dev->parent != &vdev->dev)
+                return -EINVAL;
+
+        device_unregister(dev);
+
+        return 0;
+}
+EXPORT_SYMBOL(rpmsg_destroy_channel);
+
 /* super simple buffer "allocator" that is just enough for now */
 static void *get_a_tx_buf(struct virtproc_info *vrp)
 {
@@ -964,13 +1023,14 @@ static void rpmsg_ns_cb(struct rpmsg_channel *rpdev, void *data, int len,
         chinfo.dst = msg->addr;
 
         if (msg->flags & RPMSG_NS_DESTROY) {
-                ret = rpmsg_destroy_channel(vrp, &chinfo);
+                ret = __rpmsg_destroy_channel(vrp, &chinfo);
                 if (ret)
-                        dev_err(dev, "rpmsg_destroy_channel failed: %d\n", ret);
+                        dev_err(dev, "__rpmsg_destroy_channel failed: %d\n",
+                                ret);
         } else {
-                newch = rpmsg_create_channel(vrp, &chinfo);
+                newch = __rpmsg_create_channel(vrp, &chinfo);
                 if (!newch)
-                        dev_err(dev, "rpmsg_create_channel failed\n");
+                        dev_err(dev, "__rpmsg_create_channel failed\n");
         }
 }
 
diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h
index 97aa98ccbfd..fe00b06536f 100644
--- a/include/linux/rpmsg.h
+++ b/include/linux/rpmsg.h
@@ -181,6 +181,10 @@ struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_channel *,
 int
 rpmsg_send_offchannel_raw(struct rpmsg_channel *, u32, u32, void *, int, bool);
 struct virtio_device *rpmsg_get_virtio_dev(struct rpmsg_channel *rpdev);
+struct rpmsg_channel *rpmsg_create_channel(struct virtproc_info *vrp,
+                                           const char *name, const char *desc,
+                                           int src, int dst);
+int rpmsg_destroy_channel(struct rpmsg_channel *rpdev);
 
 /**
  * rpmsg_send() - send a message across to the remote processor