Doc: Add Bluetooth basic documentation

Add basic Bluetooth documentation with sample.

Change-Id: I46077c8ee7e0ef464cda2374056fe061caaaee8b
Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>

doc/doxygen.config

@@ -102,6 +102,7 @@ INPUT                  = \
                        include/nanokernel/ \
                        kernel/microkernel/ \
                        kernel/nanokernel/ \
+                       include/bluetooth/ \
 INPUT_ENCODING         = UTF-8
 FILE_PATTERNS          = "*.c" "*.h" "*.s"
 RECURSIVE              = YES

doc/index.rst

@@ -16,6 +16,7 @@
    collaboration/collaboration.rst
    development/index.rst
    object/object.rst
+   net/network.rst
    doxygen/doxygen.rst
 
 

doc/net/network.rst

@@ -0,0 +1,13 @@
+Network Documentation
+#####################
+
+The network documentation contains information regarding the network stack
+of the Zephyr Operating System. Use the information to understand the
+principles behind the operation of the stacks and how they were implemented.
+The following network stacks have been implemented:
+
+
+.. toctree::
+   :maxdepth: 2
+
+   network_bluetooth.rst

doc/net/network_bluetooth.rst

@@ -0,0 +1,75 @@
+.. _bluetooth:
+
+Bluetooth Implementation
+########################
+
+Initialization
+**************
+
+Initialize the Bluetooth subsystem using :c:func:`bt_init()`. Caller shall be
+either task or a fiber. Caller must ensure that function succeeds by checking
+return code for errors.
+
+Application Program Interfaces
+******************************
+
++------------------------------------------+------------------------------------------------------------+
+| Call                                     | Description                                                |
++==========================================+============================================================+
+| :c:func:`bt_init()`                      | Initializes the Bluetooth subsystem                        |
++------------------------------------------+------------------------------------------------------------+
+| :c:func:`bt_start_advertising()`         | Set advertisement and scan data and start advertising      |
++------------------------------------------+------------------------------------------------------------+
+
+TODO: Describe all API
+
+Bluetooth Application Example
+*****************************
+
+A simple Bluetooth beacon application is shown below. The application
+initializes a Bluetooth Subsystem and enables non-connectable advertising.
+It acts as a Bluetooth Low Energy broadcaster.
+
+.. literalinclude:: ../../samples/bluetooth/beacon/src/main.c
+   :language: c
+   :lines: 33-
+   :linenos:
+
+Testing with QEMU
+*****************
+
+A Bluetooth application might be tested with QEMU. In order to do so,
+a Bluetooth controller needs to be connected to the emulator.
+
+Using Host System Bluetooth Controller in QEMU
+==============================================
+
+The host system's Bluetooth controller is connected to the second QEMU
+serial line through a UNIX socket
+(QEMU option :literal:`-serial unix:/tmp/bt-server-bredr`).
+This option is already added to QEMU through :makevar:`QEMU_EXTRA_FLAGS`
+in the Makefile.
+
+On the Host side, BlueZ allows to "connect" Bluetooth controller through
+a so-called user channel.
+
+#. Use the btproxy tool to open the listening UNIX socket, type:
+
+    .. code-block:: console
+
+        $ sudo tools/btproxy -u
+        Listening on /tmp/bt-server-bredr
+
+    .. note:: Ensure that the Bluetooth controller is down before using the
+              btproxy command.
+
+
+#. To run application in the QEMU, type:
+
+    .. code-block:: console
+
+        $ make qemu
+
+Running QEMU now results in a connection with the second serial line to
+:literal:`bt-server-bredr` UNIX socket.
+Now, an application can use the Bluetooth device.