doc: add IDXD docs and changelog entry

The IOAT docs are pretty limited so what's here just mirrors those.
More documentation on the library as well as the module will be
provided as an ongoing activity.

Signed-off-by: paul luse <paul.e.luse@intel.com>
Change-Id: I28b13733f034fe117a4ea21983ce0418a427dd51
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/1925
Community-CI: Mellanox Build Bot
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>

CHANGELOG.md

@@ -8,6 +8,23 @@ Legacy INI style configuration for SPDK applications has been deprecated and wil
 removed in future release.
 Please switch to JSON-RPC configuration files and/or RPC driven run-time configuration.
 
+### idxd
+
+IDXD support was added in the form of a low level library that can directly
+utilize the IDXD offload engine as well as an accel plug-in module allowing for use
+with the generic accel framework API. IDXD is the first in a family of offload
+engines that share the same interface, specifically DSA is added here. More info
+can be found here: https://01.org/blogs/2019/introducing-intel-data-streaming-accelerator
+
+Much of the implementation models IOAT, however their low level interfaces are very
+different. The RPC to enable IDXD requires a configuration number as well. The
+code includes 2 pre-defined configurations of IDXD groups/work queues/engines. A future
+version will provide an interface to allow for setting of individual configuration
+parameters.
+
+IDXD is not yet available so this feature should be considered experimental. It will
+be built up with additional documentation as an ongoing activity.
+
 ### ocf
 
 Update OCF submodule to OCF v20.03

doc/Doxyfile

@@ -814,6 +814,7 @@ INPUT                  += \
                          ftl.md \
                          gdb_macros.md \
                          getting_started.md \
+                         idxd.md \
                          ioat.md \
                          iscsi.md \
                          jsonrpc.md \

doc/driver_modules.md

@@ -2,5 +2,6 @@
 
 - @subpage nvme
 - @subpage ioat
+- @subpage idxd
 - @subpage virtio
 - @subpage vmd

doc/idxd.md

@@ -0,0 +1,21 @@
+# IDXD Driver {#idxd}
+
+# Public Interface {#idxd_interface}
+
+- spdk/idxd.h
+
+# Key Functions {#idxd_key_functions}
+
+Function                                | Description
+--------------------------------------- | -----------
+spdk_idxd_probe()                       | @copybrief spdk_idxd_probe()
+spdk_idxd_submit_copy()                 | @copybrief spdk_idxd_submit_copy()
+spdk_idxd_submit_fill()                 | @copybrief spdk_idxd_submit_fill()
+
+# Pre-defined configurations {#idxd_configs}
+
+The RPC `idxd_scan_accel_engine` is used to both enable IDXD and set it's
+configuration to one of two pre-defined configs:
+
+Config #0: 4 groups, 1 work queue per group, 1 engine per group.
+Config #1: 2 groups, 2 work queues per group, 2 engines per group.

doc/jsonrpc.md

@@ -280,6 +280,7 @@ Example response:
     "framework_monitor_context_switch",
     "spdk_kill_instance",
     "ioat_scan_accel_engine",
+    "idxd_scan_accel_engine",
     "bdev_virtio_attach_controller",
     "bdev_virtio_scsi_get_devices",
     "bdev_virtio_detach_controller",