[DeviceDriver][rbb] Add some comments and rt_rbb_blk_size/rt_rbb_blk_buf API.

Signed-off-by: armink <armink.ztl@gmail.com>

components/drivers/include/ipc/ringblk_buf.h

@@ -84,6 +84,8 @@ rt_size_t rt_rbb_get_buf_size(rt_rbb_t rbb);
 rt_rbb_blk_t rt_rbb_blk_alloc(rt_rbb_t rbb, rt_size_t blk_size);
 void rt_rbb_blk_put(rt_rbb_blk_t block);
 rt_rbb_blk_t rt_rbb_blk_get(rt_rbb_t rbb);
+rt_size_t rt_rbb_blk_size(rt_rbb_blk_t block);
+rt_uint8_t *rt_rbb_blk_buf(rt_rbb_blk_t block);
 void rt_rbb_blk_free(rt_rbb_t rbb, rt_rbb_blk_t block);
 
 /* rbb block queue API */

components/drivers/src/ringblk_buf.c

@@ -18,8 +18,10 @@
  * @param rbb ring block buffer object
  * @param buf buffer
  * @param buf_size buffer size
- * @param block_set
- * @param blk_max_num
+ * @param block_set block set
+ * @param blk_max_num max block number
+ *
+ * @note When your application need align access, please make the buffer address is aligned.
  */
 void rt_rbb_init(rt_rbb_t rbb, rt_uint8_t *buf, rt_size_t buf_size, rt_rbb_blk_t block_set, rt_size_t blk_max_num)
 {
@@ -123,6 +125,8 @@ static rt_rbb_blk_t find_empty_blk_in_set(rt_rbb_t rbb)
  * @param rbb ring block buffer object
  * @param blk_size block size
  *
+ * @note When your application need align access, please make the blk_szie is aligned.
+ *
  * @return != NULL: allocated block
  *            NULL: allocate failed
  */
@@ -133,7 +137,7 @@ rt_rbb_blk_t rt_rbb_blk_alloc(rt_rbb_t rbb, rt_size_t blk_size)
     rt_rbb_blk_t head, tail, new = NULL;
 
     RT_ASSERT(rbb);
-    RT_ASSERT(blk_size < 1L << 24);
+    RT_ASSERT(blk_size < (1L << 24));
 
     level = rt_hw_interrupt_disable();
 
@@ -277,6 +281,36 @@ __exit:
 }
 RTM_EXPORT(rt_rbb_blk_get);
 
+/**
+ * return the block size
+ *
+ * @param block the block
+ *
+ * @return block size
+ */
+rt_size_t rt_rbb_blk_size(rt_rbb_blk_t block)
+{
+    RT_ASSERT(block);
+
+    return block->size;
+}
+RTM_EXPORT(rt_rbb_blk_size);
+
+/**
+ * return the block buffer
+ *
+ * @param block the block
+ *
+ * @return block buffer
+ */
+rt_uint8_t *rt_rbb_blk_buf(rt_rbb_blk_t block)
+{
+    RT_ASSERT(block);
+
+    return block->buf;
+}
+RTM_EXPORT(rt_rbb_blk_buf);
+
 /**
  * free the block
  *