[PATCH V3 5/5] selftests/powerpc: Add README for GZIP engine tests

[Raphael Moreira Zinsly <rzinsly@linux.ibm.com>]

Include a README file with the instructions to use the
testcases at selftests/powerpc/nx-gzip.

Signed-off-by: Bulent Abali <abali@us.ibm.com>
Signed-off-by: Raphael Moreira Zinsly <rzinsly@linux.ibm.com>
---
 .../powerpc/nx-gzip/99-nx-gzip.rules          |  1 +
 .../testing/selftests/powerpc/nx-gzip/README  | 46 +++++++++++++++++++
 2 files changed, 47 insertions(+)
 create mode 100644 tools/testing/selftests/powerpc/nx-gzip/99-nx-gzip.rules
 create mode 100644 tools/testing/selftests/powerpc/nx-gzip/README

diff --git a/tools/testing/selftests/powerpc/nx-gzip/99-nx-gzip.rules b/tools/testing/selftests/powerpc/nx-gzip/99-nx-gzip.rules
new file mode 100644
index 000000000000..5a7118495cb3
--- /dev/null
+++ b/tools/testing/selftests/powerpc/nx-gzip/99-nx-gzip.rules
@@ -0,0 +1 @@
+SUBSYSTEM=="nxgzip", KERNEL=="nx-gzip", MODE="0666"
diff --git a/tools/testing/selftests/powerpc/nx-gzip/README b/tools/testing/selftests/powerpc/nx-gzip/README
new file mode 100644
index 000000000000..9a491daaef4d
--- /dev/null
+++ b/tools/testing/selftests/powerpc/nx-gzip/README
@@ -0,0 +1,46 @@
+Test the nx-gzip function:
+=========================
+
+Verify that following device exists:
+  /dev/crypto/nx-gzip
+If you get a permission error run as sudo or set the device permissions:
+   sudo chmod go+rw /dev/crypto/nx-gzip
+However, chmod may not survive across boots. You may create a udev file such
+as:
+   /etc/udev/rules.d/99-nx-gzip.rules
+
+
+Then make and run:
+$ make
+gcc -O3 -I./inc -o gzfht_test gzfht_test.c gzip_vas.c
+gcc -O3 -I./inc -o gunz_test gunz_test.c gzip_vas.c
+
+
+Compress any file using Fixed Huffman mode. Output will have a .nx.gz suffix:
+$ ./gzfht_test gzip_vas.c
+file gzip_vas.c read, 6418 bytes
+compressed 6418 to 3131 bytes total, crc32 checksum = 96b9717d
+
+
+Uncompress the previous output. Output will have a .nx.gunzip suffix:
+./gunz_test gzip_vas.c.nx.gz
+gzHeader FLG 0
+00 00 00 00 04 03
+gzHeader MTIME, XFL, OS ignored
+computed checksum 96b9717d isize 00001912
+stored   checksum 96b9717d isize 00001912
+decomp is complete: fclose
+
+
+Compare two files:
+$ sha1sum gzip_vas.c.nx.gz.nx.gunzip gzip_vas.c
+4c0b494f657c0c89a7d9f87dd3da8597be9a887a  gzip_vas.c.nx.gz.nx.gunzip
+4c0b494f657c0c89a7d9f87dd3da8597be9a887a  gzip_vas.c
+
+
+Note that the code here are intended for testing the nx-gzip hardware function.
+They are not intended for demonstrating performance or compression ratio.
+By being simplistic these selftests expect to allocate the entire set of source
+and target pages in the memory so it needs enough memory to work.
+For more information and source code consider using:
+https://github.com/libnxz/power-gzip
-- 
2.21.0