[dts] [PATCH v2] test_plans: add crc generation and computation

[Peng Yuan]

Signed-off-by: Peng Yuan <yuan.peng at intel.com>

diff --git a/test_plans/unit_tests_crc_test_plan.rst b/test_plans/unit_tests_crc_test_plan.rst
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+.. Copyright (c) <2017>, Intel Corporation
+      All rights reserved.
+
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+
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+
+=====================
+Algorithm Description
+=====================
+
+In some applications, CRC (Cyclic Redundancy Check) needs to be computed
+or updated during packet processing operations. This patchset adds software
+implementation of some common standard CRCs (32-bit Ethernet CRC as per
+Ethernet/[ISO/IEC 8802-3] and 16-bit CCITT-CRC [ITU-T X.25]).
+Two versions of each 32-bit and 16-bit CRC calculation are proposed.
+
+The first version presents a fast and efficient CRC generation on
+IA processors by using the carry-less multiplication instruction PCLMULQDQ
+(i.e SSE4.2 instrinsics). In this implementation, a parallelized folding
+approach has been used to first reduce an arbitrary length buffer to a small
+fixed size length buffer (16 bytes) with the help of precomputed constants.
+The resultant single 16-bytes chunk is further reduced by Barrett reduction
+method to generate final CRC value. For more details on the implementation,
+see reference [1].
+
+The second version presents the fallback solution to support the
+CRC generation without needing any specific support from CPU (for examples-
+SSE4.2 intrinsics). It is based on generic Look-Up Table(LUT) algorithm
+that uses precomputed 256 element table as explained in reference[2].
+
+During intialisation, all the data structures required for CRC computation
+are initialised. Also, x86 specific crc implementation
+(if supported by the platform) or scalar version is enabled.
+
+References:
+[1] Fast CRC Computation for Generic Polynomials Using PCLMULQDQ Instruction
+http://www.intel.com/content/dam/www/public/us/en/documents/white-papers
+/fast-crc-computation-generic-polynomials-pclmulqdq-paper.pdf
+[2] A PAINLESS GUIDE TO CRC ERROR DETECTION ALGORITHMS
+http://www.ross.net/crc/download/crc_v3.txt
+
+============
+CRC Autotest
+============
+
+the unit test compare the results of scalar and sse4.2 versions individually
+with the known crc results. Some of these crc results and corresponding test
+vecotrs are based on the test string mentioned in ethernet specification doc
+and x.25 doc
+
+This section explains how to run the unit tests for crc computation. The test
+can be launched independently using the command line interface.
+This test is implemented as a linuxapp environment application.
+
+The complete test suite is launched automatically using a python-expect
+script (launched using ``make test``) that sends commands to
+the application and checks the results. A test report is displayed on
+stdout.
+The steps to run the unit test manually are as follow::
+
+  # cd ~/dpdk
+  # make config T=x86_64-native-linuxapp-gcc 
+  # make test
+  # ./build/build/test/test/test -n 1 -c ffff
+  RTE>> crc_autotest
+
+The final output of the test will has to be "Test OK".
-- 
2.5.0