Add a README file for Coverity Static analysis

MISRA.md

@@ -6,7 +6,7 @@ Since the FreeRTOS-Plus-TCP library is designed for small-embedded devices, it n
 be efficient. To achieve that and to increase the performace of the IP-stack, it deviates from some MISRA rules.
 The specific deviations, suppressed inline, are listed below.
 
-Additionally, [MISRA configuration file](https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/blob/main/tools/coverity_misra.config) contains the project wide deviations.
+Additionally, [MISRA configuration file](https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/blob/main/test/Coverity/coverity_misra.config) contains the project wide deviations.
 
 ### Suppressed with Coverity Comments
 To find the violation references in the source files run grep on the source code

test/Coverity/README.md

@@ -0,0 +1,62 @@
+# Static code analysis for FreeRTOS-Plus-TCP library
+This directory is made for the purpose of statically testing the MISRA C:2012 compliance of FreeRTOS+TCP using
+[Synopsys Coverity](https://www.synopsys.com/software-integrity/security-testing/static-analysis-sast.html) static analysis tool.
+To that end, this directory provides a [CMake](https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/blob/main/test/Coverity/CMakeLists.txt)
+file and [configuration files](https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/tree/main/test/Coverity/ConfigFiles) required to build
+an application for the tool to analyze.
+
+> **Note**
+For generating the report as outlined below, we have used Coverity version 2018.09.
+
+For details regarding the suppressed violations in the report (which can be generated using the instructions described below), please
+see the [MISRA.md](https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/blob/main/MISRA.md) file.
+
+## Getting Started
+### Prerequisites
+You can run this on a platform supported by Coverity. The list and other details can be found [here](https://sig-docs.synopsys.com/polaris/topics/c_coverity-compatible-platforms.html).
+To compile and run the Coverity target successfully, you must have the following:
+
+1. CMake version > 3.13.0 (You can check whether you have this by typing `cmake --version`)
+2. GCC compiler
+    - You can see the downloading and installation instructions [here](https://gcc.gnu.org/install/).
+3. Download the repo and include the submodules using the following commands.
+    - `git clone --recurse-submodules https://github.com/FreeRTOS/FreeRTOS-Plus-TCP.git ./FreeRTOS_TCP`
+    - `cd ./FreeRTOS_TCP`
+    - `git submodule update --checkout --init --recursive`
+
+### To build and run coverity:
+Go to the root directory of the FreeRTOS-Plus-TCP repo and run the following commands in terminal:
+1. Update the compiler configuration in Coverity
+  ~~~
+  cov-configure --force --compiler cc --comptype gcc
+  ~~~
+2. Create the build files using CMake in a `build` directory
+  ~~~
+  cmake -B build -S test/Coverity
+  ~~~
+3. Go to the build directory and copy the coverity configuration file
+  ~~~
+  cd build/
+  cp ../test/Coverity/coverity_misra.config .
+  ~~~
+4. Build the (pseudo) application
+  ~~~
+  cov-build --emit-complementary-info --dir cov-out make
+  ~~~
+5. Go to the Coverity output directory (`cov-out`) and begin Coverity static analysis
+  ~~~
+  cd cov-out/
+  cov-analyze --dir . --coding-standard-config ../coverity_misra.config --tu-pattern "file('.*/FreeRTOS-Plus-TCP/source/.*')"
+  ~~~
+6. Format the errors in HTML format so that it is more readable while removing the FreeRTOS-Kernel directory from the report
+  ~~~
+  cov-format-errors --dir . --exclude-files '(.*/FreeRTOS-Kernel/.*)' --html-output html-output
+  ~~~
+
+You should now have the HTML formatted violations list in a directory named `html-output`.
+With the current configuration and the provided project, you should see only one deviation from advisory rule 8.13 in file 
+FreeRTOS_IP.c [here](https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/blob/4ac10c84a384f0414f4aec0d4be0ee7c345f2f8b/source/FreeRTOS_IP.c#L236).
+This deviation has a justification outlined [here](https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/blob/main/MISRA.md#rule-813). With
+that justification in place, a coverity suppression statement has been added to the code. However, even with that suppression in
+place, the coverity tool continues to report the deviation. Thus, as an exception, we have allowed the deviation to be reported in
+the HTML formatted report. If you find a way around it, please help us fix this by creating a pull-request in this repository.