[dpdk-dev] [PATCH v2 3/3] doc: update ISA-L guide to reflect checksum support

[Lee Daly <lee.daly@intel.com>]

This updates the ISA-L compression driver guide on how to enable and use
checksums.

This also updates the compression drivers features matrix.
Will add to release notes once the 19.02.rst file is added.

Signed-off-by: Lee Daly <lee.daly@intel.com>
---
 doc/guides/compressdevs/features/isal.ini |  2 ++
 doc/guides/compressdevs/isal.rst          | 30 ++++++++++++++++++++++++++++--
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/doc/guides/compressdevs/features/isal.ini b/doc/guides/compressdevs/features/isal.ini
index 919cf70..e705031 100644
--- a/doc/guides/compressdevs/features/isal.ini
+++ b/doc/guides/compressdevs/features/isal.ini
@@ -12,5 +12,7 @@ OOP SGL In SGL Out = Y
 OOP SGL In LB  Out = Y
 OOP LB  In SGL Out = Y
 Deflate            = Y
+Adler32            = Y
+Crc32              = Y
 Fixed              = Y
 Dynamic            = Y
diff --git a/doc/guides/compressdevs/isal.rst b/doc/guides/compressdevs/isal.rst
index 3bc3022..af1f41f 100644
--- a/doc/guides/compressdevs/isal.rst
+++ b/doc/guides/compressdevs/isal.rst
@@ -27,6 +27,33 @@ Window size support:
 
     * 32K
 
+Checksum:
+
+    * CRC32
+    * ADLER32
+
+To enable a checksum in the driver, the compression and/or decompression xform
+structure, rte_comp_xform, must be filled with either of the CompressDev
+checksum flags supported. ::
+
+ compress_xform->compress.chksum = RTE_COMP_CHECKSUM_CRC32
+
+ decompress_xform->decompress.chksum = RTE_COMP_CHECKSUM_CRC32
+
+::
+
+ compress_xform->compress.chksum = RTE_COMP_CHECKSUM_ADLER32
+
+ decompress_xform->decompress.chksum = RTE_COMP_CHECKSUM_ADLER32
+
+If you request a checksum for compression or decompression,
+the checksum field in the operation structure,  ``op->output_chksum``,
+will be filled with the checksum.
+
+.. Note::
+
+ For the compression case above, your output buffer will need to be large enough to hold the compressed data plus a scratchpad for the checksum at the end, the scratchpad is 8 bytes for CRC32 and 4 bytes for Adler32.
+
 Level guide:
 
 The ISA-L levels have been mapped to somewhat correspond to the same ZLIB level,
@@ -75,13 +102,12 @@ As a result the level mappings from the API to the PMD are shown below.
  The above table only shows mapping when API calls for dynamic compression.
  For fixed compression, regardless of API level, internally ISA-L level 0 is always used.
 
+
 Limitations
 -----------
 
 * Compressdev level 0, no compression, is not supported.
 
-* Checksums will not be supported until future release.
-
 Installation
 ------------
 
-- 
2.7.4