MLBEDSW-2063: Add contributions guidelines

 - Create new CONTRIBUTIONS.md
 - Rearrange README.md to reference new documentation

Signed-off-by: Tim Hall <tim.hall@arm.com>
Change-Id: I502b1606a3fe829a9e242a5de7391bf769203b8c

1 files changed, 89 insertions, 131 deletions

diff --git a/README.md b/README.md
index 3df86dc8..19496398 100644
--- a/README.md
+++ b/README.md
@@ -1,179 +1,137 @@
 # Vela
-This tool is used to compile a [TensorFlow Lite for Microcontrollers](https://www.tensorflow.org/lite/microcontrollers) neural network model into an optimised version that can run on an embedded system containing an [Ethos-U55 NPU](https://www.arm.com/products/silicon-ip-cpu/ethos/ethos-u55).
 
-The optimised model will contain TensorFlow Lite Custom operators for those parts of the model that can be accelerated by the Ethos-U55. Parts of the model that cannot be accelerated are left unchanged and will instead run on the Cortex-M series CPU using an appropriate kernel (such as the [Arm](https://www.arm.com) optimised [CMSIS-NN](https://github.com/ARM-software/CMSIS_5/tree/develop/CMSIS/NN) kernels).
+This tool is used to compile a
+[TensorFlow Lite for Microcontrollers](https://www.tensorflow.org/lite/microcontrollers)
+neural network model into an optimised version that can run on an embedded
+system containing an
+[Ethos-U55 NPU](https://www.arm.com/products/silicon-ip-cpu/ethos/ethos-u55).
 
-After compilation the optimised model can only be run on an Ethos-U55 NPU embedded system.
+The optimised model will contain TensorFlow Lite Custom operators for those
+parts of the model that can be accelerated by the Ethos-U55.  Parts of the model
+that cannot be accelerated are left unchanged and will instead run on the
+Cortex-M series CPU using an appropriate kernel (such as the
+[Arm](https://www.arm.com) optimised
+[CMSIS-NN](https://github.com/ARM-software/CMSIS_5/tree/develop/CMSIS/NN)
+kernels).
 
-The tool will also generate performance estimates (EXPERIMENTAL) for the compiled model.
+After compilation the optimised model can only be run on an Ethos-U55 NPU
+embedded system.
+
+The tool will also generate performance estimates (EXPERIMENTAL) for the
+compiled model.
+
+## TensorFlow Support
+
+Vela supports TensorFlow 2.1.0.
 
 ## Environment
+
 Vela runs on the Linux operating system.
 
 ## Prerequisites
+
 The following should be installed prior to the installation of Vela:
- - Python >= 3.6
- - GNU toolchain (GCC, Binutils and libraries) or alternative C compiler/linker toolchain
+
+* Python >= 3.6
+* Pip3
+* GNU toolchain (GCC, Binutils and libraries) or alternative C compiler/linker
+toolchain
+
+And optionally:
+
+* Pipenv virtual environment tool
 
 ## Installation
-Before running, the Vela package must be installed along with all its dependencies. To do this, first change to the directory that contains this README.md file. Then use the command:
-```
+
+Before running, the Vela package must be installed along with all its
+dependencies.  To do this, first change to the directory that contains this
+README.md file. Then use the command:
+
+```bash
 pip3 install -U setuptools>=40.1.0
 pip3 install .
 ```
 
-Or, if you use the `pipenv` virtual environment tool:
-```
+Or, if you use `pipenv`:
+
+```bash
 pipenv install .
 ```
 
 ## Running
-Vela is run with an input `.tflite` file passed on the command line. This file contains the neural network to be compiled. The tool then outputs an optimised version with a `_vela.tflite` file prefix, along with the performance estimate (EXPERIMENTAL) CSV files, all to the output directory.
 
-If you use the `pipenv` virtual environment tool then first start by spawning a shell in the virtual environment.:
-```
+Vela is run with an input `.tflite` file passed on the command line.  This file
+contains the neural network to be compiled. The tool then outputs an optimised
+version with a `_vela.tflite` file prefix, along with the performance estimate
+(EXPERIMENTAL) CSV files, all to the output directory.
+
+If you use the `pipenv` virtual environment tool then first start by spawning a
+shell in the virtual environment.:
+
+```bash
 pipenv shell
 ```
-After which running Vela is the same regardless of whether you are in a virtual environment or not.
+
+After which running Vela is the same regardless of whether you are in a virtual
+environment or not.
 
 Example usage:
-1) Compile the network `my_model.tflite`. The optimised version will be output to `./output/my_network_vela.tflite`.
-```
-vela my_model.tflite
-```
-2) Compile the network `/path/to/my_model.tflite` and specify the output to go in the directory `./results_dir/`.
-```
-vela --output-dir ./results_dir /path/to/my_model.tflite
-```
-3) To get a list of all available options:
-```
-vela --help
-```
-4) To specifiy information about the embedded system's configuration use Vela's system configuration file. The following command selects the `MySysConfig` settings that are described in the `sys_cfg_vela.ini` system configuration file. More details can be found in the next section.
-```
-vela --config sys_cfg_vela.ini --system-config MySysConfig my_model.tflite
-```
 
-### Vela's System Configuration file
-This is used to describe various properties of the embedded system that the network will run in.
+1) Compile the network `my_model.tflite`. The optimised version will be output
+to `./output/my_network_vela.tflite`.
 
-Example of a Vela system configuration file.
-```
-; File: sys_cfg_vela.ini
-; The file contains two parts; a system config part and a CPU operator
-; performance part.
-
-; System config
-; Specifies properties such as the core clock speed, the size and speed of the
-; four potential memory areas, and for various types of data which memory area
-; is used to store them. The cpu property is used to link with the CPU operator
-; performance.
-; The four potential memory areas are: Sram, Dram, OnChipFlash, OffChipFlash.
-
-[SysConfig.MySysConfig]
-npu_freq=500e6
-cpu=MyCpu
-Sram_clock_scale=1
-Sram_port_width=64
-Dram_clock_scale=1
-Dram_port_width=64
-OnChipFlash_clock_scale=1
-OnChipFlash_port_width=64
-OffChipFlash_clock_scale=0.25
-OffChipFlash_port_width=32
-permanent_storage_mem_area=OffChipFlash
-feature_map_storage_mem_area=Sram
-fast_storage_mem_area=Sram
-
-; CPU operator performance
-; Specifies properties that are used by a linear model to estimate the
-; performance for any operations that will be run on the CPU (such as those not
-; supported by the NPU). Setting the intercept and slope to 0 will result in
-; the operator being excluded from the performance estimation. This is the same
-; as not specifying the operator. If an explicit cpu is specified rather than
-; using the default then the cpu name must match the cpu specified in the
-; SysConfig.<system config name> section.
-
-[CpuPerformance.MyCpuOperator]
-default.intercept=0.0
-default.slope=1.0
-
-MyCpu.intercept=0.0
-MyCpu.slope=1.0
+```bash
+vela my_model.tflite
 ```
 
-## Contribution Guidlines and Pull Requests
-Contributions are accepted under [Apache License 2.0](LICENSE.txt). Only submit contributions where you have authored all of the code.
+1) Compile the network `/path/to/my_model.tflite` and specify the output to go
+in the directory `./results_dir/`.
 
-## Resources
-* [Ethos-U55](https://www.arm.com/products/silicon-ip-cpu/ethos/ethos-u55)
+```bash
+vela --output-dir ./results_dir /path/to/my_model.tflite
+```
 
-## License
-Vela is licensed under [Apache License 2.0](LICENSE.txt)
+1) To specify information about the embedded system's configuration use Vela's
+system configuration file. The following command selects the `MySysConfig`
+settings that are described in the `sys_cfg_vela.ini` system configuration file.
+More details can be found in the next section.
 
-## Contributions and Pull Requests
+```bash
+vela --config sys_cfg_vela.ini --system-config MySysConfig my_model.tflite
+```
 
-Contributions are accepted under Apache-2.0. Only submit contributions where you have authored all of the code.
+1) To get a list of all available options:
 
-### Sanity checks and tests
+```bash
+vela --help
+```
 
-The Python codebase is PEP8 compliant with the exception of 120 characters line length.
-We run reorder-python-import, black and flake8 against the code base excluding "ethosu/vela/tflite/" and "ethosu/vela/ethos\_u55\_regs" directories because they are auto-generated by third party tools.
-Those tools are run using [pre-commit framework](https://pre-commit.com/). The configuration file is .pre-commit-config.yaml
+Information about all of Vela's CLI options as well as the system configuration
+file format can be found in [Vela Options](OPTIONS.md)
 
-#### Install tools
+## Testing
 
-To install pre-commit, run the following:
+Please see [Vela Testing](TESTING.md)
 
-```
-pipenv install -e . --dev
-```
-
-After the installation, pre-commit is available in the virtual environment.
-Besides pre-commit, we install also:
-* pytest: testing framework
-* pytest-cov: code coverage plugin for pytest
+## Contributions
 
-#### Install the pre-commit hook
+Please see [Vela Contributions](CONTRIBUTIONS.md).
 
-To ease the development, we can run those sanity checks before committing the code.
-To install the git hook, run:
+## Security
 
-```
-$ pre-commit install
-pre-commit installed at .git/hooks/pre-commit
-```
+Please see [Vela Security](SECURITY.md).
 
-The checks will be run before the commit: if one of them fails, you need to fix the code to make the checks pass.
+## Releases
 
-#### Run the tests
+Please see [Vela Releases](RELEASES.md).
 
-Tests and test coverage can be run using pre-commit framework.
+## Resources
 
-```
-$ pre-commit run pytest
-...
-$ pre-commit run pytest-cov
-```
+Additional useful information:
 
-#### Run the sanity checks
+* [Arm Products: Ethos-U55](https://www.arm.com/products/silicon-ip-cpu/ethos/ethos-u55)
+* [Arm Developer: Ethos-U55](https://developer.arm.com/ip-products/processors/machine-learning/ethos-u55)
 
-Those checks can be run manually. This can be achievied running the following
-```
-$ pre-commit run reorder-python-imports --all-files
-...
-$ pre-commit run flake8 --all-files
-...
-$ pre-commit run black --all-files
-```
+## License
 
-If you don't specify anything after run, it will execute all the checks.
-```
-$ pre-commit run --all-files
-Reorder python imports...................................................Passed
-black....................................................................Passed
-flake8...................................................................Passed
-pytest...................................................................Passed
-...
-...
-```
+Vela is licensed under [Apache License 2.0](LICENSE.txt)