doc: add zlib PMD guide

Add zlib pmd feature support and user guide with
build and run instructions

Signed-off-by: Sunila Sahu <sunila.sahu@caviumnetworks.com>
Signed-off-by: Shally Verma <shally.verma@caviumnetworks.com>
Signed-off-by: Ashish Gupta <ashish.gupta@caviumnetworks.com>

MAINTAINERS

@@ -875,6 +875,8 @@ F: doc/guides/compressdevs/features/isal.ini
 ZLIB
 M: Sunila Sahu <sunila.sahu@caviumnetworks.com>
 F: drivers/compress/zlib/
+F: doc/guides/compressdevs/zlib.rst
+F: doc/guides/compressdevs/features/zlib.ini
 
 
 Eventdev Drivers

doc/guides/compressdevs/features/zlib.ini

@@ -0,0 +1,10 @@
+;
+; Refer to default.ini for the full list of available PMD features.
+;
+; Supported features of 'ZLIB' compression driver.
+;
+[Features]
+Pass-through   = Y
+Deflate        = Y
+Fixed          = Y
+Dynamic        = Y

doc/guides/compressdevs/index.rst

@@ -12,3 +12,4 @@ Compression Device Drivers
     overview
     isal
     qat_comp
+    zlib

doc/guides/compressdevs/zlib.rst

@@ -0,0 +1,69 @@
+..  SPDX-License-Identifier: BSD-3-Clause
+    Copyright(c) 2018 Cavium Networks.
+
+ZLIB Compression Poll Mode Driver
+==================================
+
+The ZLIB PMD (**librte_pmd_zlib**) provides poll mode compression &
+decompression driver based on SW zlib library,
+
+Features
+--------
+
+ZLIB PMD has support for:
+
+Compression/Decompression algorithm:
+
+* DEFLATE
+
+Huffman code type:
+
+* FIXED
+* DYNAMIC
+
+Window size support:
+
+* Min - 256 bytes
+* Max - 32K
+
+Limitations
+-----------
+
+* Scatter-Gather and Stateful not supported.
+
+Installation
+------------
+
+* To build DPDK with ZLIB library, the user is required to download the ``libz`` library.
+* Use following command for installation.
+
+* For Fedora users::
+     sudo yum install zlib-devel
+* For Ubuntu users::
+     sudo apt-get install zlib1g-dev
+
+* Once downloaded, the user needs to build the library.
+
+* To build from sources
+  download zlib sources from http://zlib.net/ and do following before building DPDK::
+
+    make
+    sudo make install
+
+Initialization
+--------------
+
+In order to enable this virtual compression PMD, user must:
+
+* Set ``CONFIG_RTE_LIBRTE_PMD_ZLIB=y`` in config/common_base.
+
+To use the PMD in an application, user must:
+
+* Call ``rte_vdev_init("compress_zlib")`` within the application.
+
+* Use ``--vdev="compress_zlib"`` in the EAL options, which will call ``rte_vdev_init()`` internally.
+
+The following parameter (optional) can be provided in the previous two calls:
+
+* ``socket_id:`` Specify the socket where the memory for the device is going to be allocated
+  (by default, socket_id will be the socket where the core that is creating the PMD is running on).