139 lines
3.6 KiB
ReStructuredText
139 lines
3.6 KiB
ReStructuredText
.. _application_porting_guide:
|
|
|
|
Legacy Applications Porting Guide
|
|
##################################
|
|
|
|
|
|
.. note::
|
|
|
|
This document is still work in progress.
|
|
|
|
This guide will help you move your applications from the nanokernel/microkernel
|
|
model to the unified kernel. The unified kernel was introduced with
|
|
:ref:`zephyr_1.6` which was released late 2016.
|
|
|
|
A list of the major changes that came with the unified kernel can be found in
|
|
the section :ref:`changes_v2`.
|
|
|
|
|
|
API Changes
|
|
***********
|
|
|
|
As described in the section :ref:`kernel_api_changes` the kernel now has one
|
|
unified and consistent API with new naming.
|
|
|
|
An application using the old APIs can still be compiled using a legacy interface
|
|
that translates old APIs to the new APIs. This legacy interface maintained in
|
|
:file:`include/legacy.h` can be used as a guide when porting a legacy
|
|
application to the new kernel.
|
|
|
|
Same Arguments
|
|
==============
|
|
|
|
In many cases, a simple search and replace is enough to move from the legacy to
|
|
the new APIs, for example:
|
|
|
|
* :cpp:func:`task_abort()` -> :cpp:func:`k_thread_abort()`
|
|
* :cpp:func:`task_sem_count_get()` -> :cpp:func:`k_sem_count_get()`
|
|
|
|
Additional Arguments
|
|
====================
|
|
The number of arguments to some APIs have changed,
|
|
|
|
* :cpp:func:`nano_sem_init()` -> :cpp:func:`k_sem_init()`
|
|
|
|
This function now accepts 2 additional arguments:
|
|
|
|
- Initial semaphore count
|
|
- Permitted semaphore count
|
|
|
|
When porting your application, make sure you have set the right arguments. For
|
|
example, calls to the old API:
|
|
|
|
.. code-block:: c
|
|
|
|
nano_sem_init(sem)
|
|
|
|
depending on the usage becomes in most cases:
|
|
|
|
.. code-block:: c
|
|
|
|
k_sem_init(sem, 0, UINT_MAX);
|
|
|
|
Return Codes
|
|
============
|
|
|
|
Many kernel APIs now return 0 to indicate success and a non-zero error code
|
|
to indicate the reason for failure. You should pay special attention to this
|
|
change when checking for return codes from kernel APIs, for example:
|
|
|
|
* :cpp:func:`k_sem_take()` now returns 0 on on success, in the legacy API
|
|
:cpp:func:`nano_sem_take()` returned 1 when a semaphore is available.
|
|
|
|
|
|
Application Porting
|
|
*******************
|
|
|
|
The existing :ref:`synchronization_sample` from the Zephyr tree will be used to
|
|
guide you with porting a legacy application to the new kernel.
|
|
|
|
The code has been ported to the new kernel and is shown below:
|
|
|
|
.. literalinclude:: sync_v2.c
|
|
:linenos:
|
|
:language: c
|
|
:lines: 9-
|
|
|
|
Porting a Nanokernel Application
|
|
=================================
|
|
|
|
Below is the code for the application using the legacy kernel:
|
|
|
|
.. literalinclude:: sync_v1_nano.c
|
|
:linenos:
|
|
:language: c
|
|
:lines: 9-
|
|
|
|
Porting a Microkernel Application
|
|
=================================
|
|
|
|
The MDEF feature of the legacy kernel has been eliminated. Consequently, all
|
|
kernel objects are now defined directly in code.
|
|
|
|
Below is the code for the application using the legacy kernel:
|
|
|
|
.. literalinclude:: sync_v1.c
|
|
:linenos:
|
|
:language: c
|
|
:lines: 9-
|
|
|
|
|
|
A microkernel application defines the used objects in an MDEF file, for this
|
|
porting sample using the :ref:`synchronization_sample`, the file is shown below:
|
|
|
|
.. literalinclude:: v1.mdef
|
|
:linenos:
|
|
|
|
In the unified kernel the semaphore will be defined in the code as follows:
|
|
|
|
.. literalinclude:: sync_v2.c
|
|
:linenos:
|
|
:language: c
|
|
:lines: 51-54
|
|
|
|
The threads (previously named tasks) are defined in the code as follows, for
|
|
thread A:
|
|
|
|
.. literalinclude:: sync_v2.c
|
|
:linenos:
|
|
:language: c
|
|
:lines: 88-89
|
|
|
|
Thread B (taskB in the microkernel) will be spawned dynamically from thread A
|
|
(See :ref:`spawning_thread` section):
|
|
|
|
.. literalinclude:: sync_v2.c
|
|
:linenos:
|
|
:language: c
|
|
:lines: 80-82
|