microkernel: introduce support for private pipes

This enable defining pipes in source code in addition to
defining in MDEF files. This introduces the macro
DEFINE_PIPE(pipe_name, ...). The pipes created this
way are the same, in functionality, as those defined in MDEF
files. They can be manipulated by the standard microkernel
pipe APIs.

Define the pipe using:

  DEFINE_PIPE(pipe1, size);

and "pipe1" can be used, for example:

  task_pipe_put(pipe1, ...);

or,

  task_pipe_get(pipe1, ...);

etc.

To use the pipe defined in another source file, simply add:

extern const kpipe_t pipe1;

to the desired C or header file.

Change-Id: Iae8e04706359bc18aae51acc75df3e3d26388882
Signed-off-by: Daniel Leung <daniel.leung@intel.com>

doc/object/microkernel_pipes.rst

@@ -40,8 +40,8 @@ and receiver identities.
 Usage
 =====
 
-Defining a pipe
----------------
+Defining a pipe in MDEF file
+----------------------------
 
 The following parameters must be defined:
 
@@ -67,6 +67,35 @@ For example, the file :file:`projName.mdef` defines a pipe as follows:
    % ===============================
      PIPE   DATA_PIPE        1024
 
+
+Defining pipes in source code
+-----------------------------
+
+In addition to defining pipes in MDEF file, it is also possible to
+define pipes inside code. The macro ``DEFINE_PIPE(...)`` can be
+used for this purpose.
+
+For example, the following code can be used to define a global pipe
+``PRIV_PIPE``.
+
+.. code-block:: c
+
+   DEFINE_PIPE(PRIV_PIPE, size);
+
+where the parameters are the same as pipes defined in MDEF file.
+The task ``PRIV_PIPE`` can be used in the same style as those
+defined in MDEF file.
+
+It is possible to utilize this pipe in another source file, simply
+add:
+
+.. code-block:: c
+
+   extern const kpipe_t PRIV_PIPE;
+
+to that file. The pipe ``PRIV_PIPE`` can be then used there.
+
+
 Example: Writing Fixed-Size Data Items to a Pipe
 ------------------------------------------------
 

include/arch/arm/CortexM/scripts/linker.cmd

@@ -207,6 +207,7 @@ SECTIONS
 	{
 		_k_pipe_ptr_start = .;
 			*(._k_pipe_ptr.public.*)
+			*(._k_pipe_ptr.private.*)
 		KEEP(*(SORT_BY_NAME("._k_pipe_ptr*")))
 		_k_pipe_ptr_end = .;
 	} GROUP_LINK_IN(RAMABLE_REGION)

include/arch/x86/linker-common-sections.h

@@ -178,6 +178,7 @@ SECTIONS
 	{
 		_k_pipe_ptr_start = .;
 			*(._k_pipe_ptr.public.*)
+			*(._k_pipe_ptr.private.*)
 		KEEP(*(SORT_BY_NAME("._k_pipe_ptr*")))
 		_k_pipe_ptr_end = .;
 	} GROUP_LINK_IN(RAM)

include/microkernel/pipe.h

@@ -37,6 +37,8 @@
 extern "C" {
 #endif
 
+#include <sections.h>
+
 extern int _task_pipe_put(kpipe_t id,
 						  void *pBuffer,
 						  int iNbrBytesToWrite,
@@ -75,6 +77,31 @@ extern int _task_pipe_put_async(kpipe_t id,
 #define task_pipe_put_async(id, block, size, sema) \
 			_task_pipe_put_async(id, block, size, sema)
 
+/**
+ * @brief Initialize a pipe struct.
+ *
+ * @param size Size of pipe buffer.
+ * @param buffer Pointer to the buffer.
+ */
+#define __K_PIPE_INITIALIZER(size, buffer) \
+	{ \
+	  .iBufferSize = size, \
+	  .Buffer = buffer, \
+	}
+
+/**
+ * @brief Define a private microkernel pipe.
+ *
+ * @param name Name of the pipe.
+ * @param size Size of the pipe buffer, in bytes.
+ */
+#define DEFINE_PIPE(name, size) \
+	char __noinit __pipe_buffer_##name[size]; \
+	struct _k_pipe_struct _k_pipe_obj_##name = \
+		__K_PIPE_INITIALIZER(size, __pipe_buffer_##name); \
+	const kpipe_t name \
+		__section(_k_pipe_ptr, private, pipe) = \
+		(kpipe_t)&_k_pipe_obj_##name;
 
 #ifdef __cplusplus
 }

scripts/sysgen

@@ -592,7 +592,7 @@ def kernel_main_c_pipes():
         size = pipe[1]
         buffer = "__" + pipe[0] + "_buffer"
         kernel_main_c_out("struct _k_pipe_struct _k_pipe_obj_%s = " % (name) +
-            "    {%d, %s};\n" % (size, buffer) +
+            "    __K_PIPE_INITIALIZER(%d, %s);\n" % (size, buffer) +
             "kpipe_t _k_pipe_ptr_%s " % (name) +
             "    __section(_k_pipe_ptr, public, pipe) =\n" +
             "    (kpipe_t)&_k_pipe_obj_%s;\n" % (name))
@@ -744,8 +744,7 @@ def kernel_main_c_node_init():
 
     kernel_main_c_out("\n" +
         "void _k_init_node(void)\n{\n")
-    if (len(pipe_list) > 0):
-        kernel_main_c_out("    _k_pipe_init();\n")
+    kernel_main_c_out("    _k_pipe_init();\n")
     if (len(map_list) > 0):
         kernel_main_c_out("    _k_mem_map_init();\n")
     if (len(pool_list) > 0):