unified: Tweak msgq API parameters

- Reorders parameters where necessary
 - Adds alignment parameter to K_MSGQ_DEFINE() for buffer alignment
 - Renames parameters where necessary so they are more intuitive

Change-Id: I0b53105c04109127897bf4790e6908082f82da4e
Signed-off-by: Peter Mitsis <peter.mitsis@windriver.com>

doc/kernel_v2/data_passing/message_queues.rst

@@ -73,10 +73,10 @@ that is capable of holding 10 items.
         ...
     };
 
-    char my_msgq_buffer[10 * sizeof(data_item_type)];
+    char __aligned(4) my_msgq_buffer[10 * sizeof(data_item_type)];
     struct k_msgq my_msgq;
 
-    k_msgq_init(&my_msgq, 10, sizeof(data_item_type), my_msgq_buffer);
+    k_msgq_init(&my_msgq, my_msgq_buffer, sizeof(data_item_type), 10);
 
 Alternatively, a message queue can be defined and initialized at compile time
 by calling :c:macro:`K_MSGQ_DEFINE()`.
@@ -86,7 +86,7 @@ that the macro defines both the message queue and its buffer.
 
 .. code-block:: c
 
-    K_MSGQ_DEFINE(my_msgq, 10, sizeof(data_item_type));
+    K_MSGQ_DEFINE(my_msgq, sizeof(data_item_type), 10, 4);
 
 Writing to a Message Queue
 ==========================

include/kernel.h

@@ -856,26 +856,43 @@ struct k_msgq {
 	_DEBUG_TRACING_KERNEL_OBJECTS_NEXT_PTR(k_msgq);
 };
 
-#define K_MSGQ_INITIALIZER(obj, q_depth, q_width, q_buffer) \
+#define K_MSGQ_INITIALIZER(obj, q_buffer, q_msg_size, q_max_msgs) \
 	{ \
 	.wait_q = SYS_DLIST_STATIC_INIT(&obj.wait_q), \
-	.max_msgs = q_depth, \
-	.msg_size = q_width, \
+	.max_msgs = q_max_msgs, \
+	.msg_size = q_msg_size, \
 	.buffer_start = q_buffer, \
-	.buffer_end = q_buffer + (q_depth * q_width), \
+	.buffer_end = q_buffer + (q_max_msgs * q_msg_size), \
 	.read_ptr = q_buffer, \
 	.write_ptr = q_buffer, \
 	.used_msgs = 0, \
 	_DEBUG_TRACING_KERNEL_OBJECTS_INIT \
 	}
 
-#define K_MSGQ_DEFINE(name, q_depth, q_width) \
-	static char __noinit _k_fifo_buf_##name[(q_depth) * (q_width)]; \
-	struct k_msgq name = \
-	       K_MSGQ_INITIALIZER(name, q_depth, q_width, _k_fifo_buf_##name)
+/**
+ * @brief Define a message queue
+ *
+ * This declares and initializes a message queue whose buffer is aligned to
+ * a @a q_align -byte boundary. The new message queue can be passed to the
+ * kernel's message queue functions.
+ *
+ * Note that for each of the mesages in the message queue to be aligned to
+ * @a q_align bytes, then @a q_msg_size must be a multiple of @a q_align.
+ *
+ * @param q_name Name of the message queue
+ * @param q_msg_size The size in bytes of each message
+ * @param q_max_msgs Maximum number of messages the queue can hold
+ * @param q_align Alignment of the message queue's buffer (power of 2)
+ */
+#define K_MSGQ_DEFINE(q_name, q_msg_size, q_max_msgs, q_align)      \
+	static char __noinit __aligned(q_align)                     \
+		_k_fifo_buf_##q_name[(q_max_msgs) * (q_msg_size)];  \
+	struct k_msgq q_name =                                      \
+	       K_MSGQ_INITIALIZER(q_name, _k_fifo_buf_##q_name,     \
+				  q_msg_size, q_max_msgs)
 
-extern void k_msgq_init(struct k_msgq *q, uint32_t msg_size,
-			uint32_t max_msgs, char *buffer);
+extern void k_msgq_init(struct k_msgq *q, char *buffer,
+			uint32_t msg_size, uint32_t max_msgs);
 extern int k_msgq_put(struct k_msgq *q, void *data, int32_t timeout);
 extern int k_msgq_get(struct k_msgq *q, void *data, int32_t timeout);
 extern void k_msgq_purge(struct k_msgq *q);

include/legacy.h

@@ -445,7 +445,7 @@ static inline int task_fifo_size_get(kfifo_t queue)
 }
 
 #define DEFINE_FIFO(name, q_depth, q_width) \
-	K_MSGQ_DEFINE(_k_fifo_obj_##name, q_depth, q_width); \
+	K_MSGQ_DEFINE(_k_fifo_obj_##name, q_width, q_depth, 4); \
 	struct k_msgq * const name = &_k_fifo_obj_##name
 
 /* mailboxes */

kernel/unified/msg_q.c

@@ -33,14 +33,14 @@
  * @brief Initialize a message queue.
  *
  * @param q Pointer to the message queue object.
+ * @param buffer Pointer to memory area that holds queued messages.
  * @param msg_size Message size, in bytes.
  * @param max_msgs Maximum number of messages that can be queued.
- * @param buffer Pointer to memory area that holds queued messages.
  *
  * @return N/A
  */
-void k_msgq_init(struct k_msgq *q, uint32_t msg_size, uint32_t max_msgs,
-		 char *buffer)
+void k_msgq_init(struct k_msgq *q, char *buffer,
+		 uint32_t msg_size, uint32_t max_msgs)
 {
 	q->msg_size = msg_size;
 	q->max_msgs = max_msgs;

scripts/sysgen

@@ -684,8 +684,8 @@ def kernel_main_c_fifos():
             name = fifo[0]
             depth = fifo[1]
             width = fifo[2]
-            kernel_main_c_out("K_MSGQ_DEFINE(_k_fifo_obj_%s, %s, %s);\n" %
-                              (name, depth, width))
+            kernel_main_c_out("K_MSGQ_DEFINE(_k_fifo_obj_%s, %s, %s, 4);\n" %
+                              (name, width, depth))
 
 
 def kernel_main_c_pipes():