Improve documentation and beatify pieces of code

doc/source/firmware/safety/index.rst

@@ -21,4 +21,5 @@ which are used to retain boot information across resets, for example to communic
 	flags
 	backup-ram
 	error-handling
+	startup-tests
 	stack-checking

doc/source/firmware/safety/startup-tests.rst

@@ -0,0 +1,23 @@
+.. _safety_startup_tests:
+
+Startup Tests
+=============
+
+The following tests will be performed after each reset / power cycle of the controller.
+
+Internal Memory Test
+--------------------
+Directly after startup and after setting up the system clocks, the controller performs memory checks on the internal SRAM and the core coupled memory.
+
+RAM checking is performed by testing the following sequences:
+
+- Alternating 0x55AA55AA / 0xAA55AA55 pattern
+- Alternating 0xAA55AA55 / 0x55AA55AA pattern
+- 0xFFFFFFFF constant value
+- 0x00000000 constant value
+
+The following functions implement the RAM checking:
+
+.. doxygenfunction:: startup_test_perform_ccm_ram_check
+
+.. doxygenfunction:: startup_test_perform_system_ram_check