rpmsg: rpmsg_send() operations takes rpmsg_endpoint

The rpmsg_send() operations has been taking a rpmsg_device, but this
forces users of secondary rpmsg_endpoints to use the rpmsg_sendto()
interface - by extracting source and destination from the given data
structures. If we instead pass the rpmsg_endpoint to these functions a
service can use rpmsg_sendto() to respond to messages, even on secondary
endpoints.

In addition this would allow us to support operations on multiple
channels in future backends that does not support off-channel
operations.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h
index 2b97c71..a901a33 100644
--- a/include/linux/rpmsg.h
+++ b/include/linux/rpmsg.h
@@ -193,13 +193,14 @@
 
 /**
  * rpmsg_send() - send a message across to the remote processor
- * @rpdev: the rpmsg channel
+ * @ept: the rpmsg endpoint
  * @data: payload of message
  * @len: length of payload
  *
- * This function sends @data of length @len on the @rpdev channel.
- * The message will be sent to the remote processor which the @rpdev
- * channel belongs to, using @rpdev's source and destination addresses.
+ * This function sends @data of length @len on the @ept endpoint.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to, using @ept's address and its associated rpmsg
+ * device destination addresses.
  * In case there are no TX buffers available, the function will block until
  * one becomes available, or a timeout of 15 seconds elapses. When the latter
  * happens, -ERESTARTSYS is returned.
@@ -208,23 +209,24 @@
  *
  * Returns 0 on success and an appropriate error value on failure.
  */
-static inline int rpmsg_send(struct rpmsg_channel *rpdev, void *data, int len)
+static inline int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
 {
-	u32 src = rpdev->src, dst = rpdev->dst;
+	struct rpmsg_channel *rpdev = ept->rpdev;
+	u32 src = ept->addr, dst = rpdev->dst;
 
 	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
 }
 
 /**
  * rpmsg_sendto() - send a message across to the remote processor, specify dst
- * @rpdev: the rpmsg channel
+ * @ept: the rpmsg endpoint
  * @data: payload of message
  * @len: length of payload
  * @dst: destination address
  *
  * This function sends @data of length @len to the remote @dst address.
- * The message will be sent to the remote processor which the @rpdev
- * channel belongs to, using @rpdev's source address.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to, using @ept's address as source.
  * In case there are no TX buffers available, the function will block until
  * one becomes available, or a timeout of 15 seconds elapses. When the latter
  * happens, -ERESTARTSYS is returned.
@@ -234,16 +236,17 @@
  * Returns 0 on success and an appropriate error value on failure.
  */
 static inline
-int rpmsg_sendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst)
+int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
 {
-	u32 src = rpdev->src;
+	struct rpmsg_channel *rpdev = ept->rpdev;
+	u32 src = ept->addr;
 
 	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
 }
 
 /**
  * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
- * @rpdev: the rpmsg channel
+ * @ept: the rpmsg endpoint
  * @src: source address
  * @dst: destination address
  * @data: payload of message
@@ -251,8 +254,8 @@
  *
  * This function sends @data of length @len to the remote @dst address,
  * and uses @src as the source address.
- * The message will be sent to the remote processor which the @rpdev
- * channel belongs to.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to.
  * In case there are no TX buffers available, the function will block until
  * one becomes available, or a timeout of 15 seconds elapses. When the latter
  * happens, -ERESTARTSYS is returned.
@@ -262,21 +265,24 @@
  * Returns 0 on success and an appropriate error value on failure.
  */
 static inline
-int rpmsg_send_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst,
+int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 			  void *data, int len)
 {
+	struct rpmsg_channel *rpdev = ept->rpdev;
+
 	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
 }
 
 /**
  * rpmsg_send() - send a message across to the remote processor
- * @rpdev: the rpmsg channel
+ * @ept: the rpmsg endpoint
  * @data: payload of message
  * @len: length of payload
  *
- * This function sends @data of length @len on the @rpdev channel.
- * The message will be sent to the remote processor which the @rpdev
- * channel belongs to, using @rpdev's source and destination addresses.
+ * This function sends @data of length @len on the @ept endpoint.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to, using @ept's address as source and its associated
+ * rpdev's address as destination.
  * In case there are no TX buffers available, the function will immediately
  * return -ENOMEM without waiting until one becomes available.
  *
@@ -285,23 +291,24 @@
  * Returns 0 on success and an appropriate error value on failure.
  */
 static inline
-int rpmsg_trysend(struct rpmsg_channel *rpdev, void *data, int len)
+int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
 {
-	u32 src = rpdev->src, dst = rpdev->dst;
+	struct rpmsg_channel *rpdev = ept->rpdev;
+	u32 src = ept->addr, dst = rpdev->dst;
 
 	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
 }
 
 /**
  * rpmsg_sendto() - send a message across to the remote processor, specify dst
- * @rpdev: the rpmsg channel
+ * @ept: the rpmsg endpoint
  * @data: payload of message
  * @len: length of payload
  * @dst: destination address
  *
  * This function sends @data of length @len to the remote @dst address.
- * The message will be sent to the remote processor which the @rpdev
- * channel belongs to, using @rpdev's source address.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to, using @ept's address as source.
  * In case there are no TX buffers available, the function will immediately
  * return -ENOMEM without waiting until one becomes available.
  *
@@ -310,16 +317,17 @@
  * Returns 0 on success and an appropriate error value on failure.
  */
 static inline
-int rpmsg_trysendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst)
+int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
 {
-	u32 src = rpdev->src;
+	struct rpmsg_channel *rpdev = ept->rpdev;
+	u32 src = ept->addr;
 
 	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
 }
 
 /**
  * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
- * @rpdev: the rpmsg channel
+ * @ept: the rpmsg endpoint
  * @src: source address
  * @dst: destination address
  * @data: payload of message
@@ -327,8 +335,8 @@
  *
  * This function sends @data of length @len to the remote @dst address,
  * and uses @src as the source address.
- * The message will be sent to the remote processor which the @rpdev
- * channel belongs to.
+ * The message will be sent to the remote processor which the @ept
+ * endpoint belongs to.
  * In case there are no TX buffers available, the function will immediately
  * return -ENOMEM without waiting until one becomes available.
  *
@@ -337,9 +345,11 @@
  * Returns 0 on success and an appropriate error value on failure.
  */
 static inline
-int rpmsg_trysend_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst,
+int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 			     void *data, int len)
 {
+	struct rpmsg_channel *rpdev = ept->rpdev;
+
 	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
 }