docs: add no-copy user API description

Add short description of the no-copy user interface. Add some sub-chapters to increase the readability. Signed-off-by: Arnaud Pouliquen <[email protected]>
noisesignal · Oct 18, 2022 · 753a203 · 753a203
1 parent 4e1fa03
commit 753a203
Showing 1 changed file with 39 additions and 0 deletions.
diff --git a/docs/rpmsg-design.md b/docs/rpmsg-design.md
@@ -36,6 +36,7 @@ running on two processors.
   ```
   struct rpmsg_device *rpmsg_virtio_get_rpmsg_device(struct rpmsg_virtio_device *rvdev)
   ```
+### RPMsg virtio endpoint APIs
 * Create RPMsg endpoint:
   ```
   int rpmsg_create_ept(struct rpmsg_endpoint *ept,
@@ -52,6 +53,7 @@ running on two processors.
   ```
   int is_rpmsg_ept_ready(struct rpmsg_endpoint *ept)
   ```
+### RPMsg messaging APIs
 * Send message with RPMsg endpoint default binding:
   ```
   int rpmsg_send(struct rpmsg_endpoint *ept, const void *data, int len)
@@ -88,6 +90,43 @@ running on two processors.
 			       const void *data, int len)`
   ```
 
+* Hold the rx buffer for usage outside the receive callback:
+  ```
+  void rpmsg_hold_rx_buffer(struct rpmsg_endpoint *ept, void *rxbuf)
+  ```
+
+* Release the rx buffer held thanks to the rpmsg_hold_rx_buffer() function:
+  ```
+  void rpmsg_release_rx_buffer(struct rpmsg_endpoint *ept, void *rxbuf)
+
+  ```
+* Gets the tx buffer for message payload.
+  ```
+  void *rpmsg_get_tx_payload_buffer(struct rpmsg_endpoint *ept,
+          uint32_t *len, int wait)
+  ```
+
+* Using a buffer obtained by calling the rpmsg_get_tx_payload_buffer() function,
+    Send a message with the RPMsg endpoint default binding:
+  ```
+  int rpmsg_send_nocopy(struct rpmsg_endpoint *ept,
+            const void *data, int len)
+  ```
+
+* Using a buffer obtained by calling the rpmsg_get_tx_payload_buffer() function,
+    send a message with RPMsg endpoint, specifying the destination address:
+  ```
+  int rpmsg_sendto_nocopy(struct rpmsg_endpoint *ept,
+              const void *data, int len, uint32_t dst)
+  ```
+
+* Using a buffer obtained by calling the rpmsg_get_tx_payload_buffer() function,
+    send a message with RPMsg endpoint using explicit source and destination addresses:
+  ```
+  int rpmsg_send_offchannel_nocopy(struct rpmsg_endpoint *ept, uint32_t src,
+          uint32_t dst, const void *data, int len)
+  ```
+
 * Releases unused Tx buffer reserved by rpmsg_get_tx_payload_buffer() function:
   ```
   int rpmsg_release_tx_buffer(struct rpmsg_endpoint *ept, void *txbuf)