[dpdk-dev] [PATCH] doc: update Marvell OCTEON TX2 LBK support

[<jerinj@marvell.com>]

From: Jerin Jacob <jerinj@marvell.com>

Add LBK HW block abstraction details and the application
usage models.

This patch also updates missing DPI HW block to DPDK
subsystem mapping as well.

Signed-off-by: Jerin Jacob <jerinj@marvell.com>
---
 doc/guides/platform/octeontx2.rst | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/doc/guides/platform/octeontx2.rst b/doc/guides/platform/octeontx2.rst
index f5be973a5..4194a4358 100644
--- a/doc/guides/platform/octeontx2.rst
+++ b/doc/guides/platform/octeontx2.rst
@@ -61,6 +61,10 @@ DPDK subsystem.
    +---+-----+--------------------------------------------------------------+
    | 6 | TIM | rte_event_timer_adapter                                      |
    +---+-----+--------------------------------------------------------------+
+   | 7 | LBK | rte_ethdev                                                   |
+   +---+-----+--------------------------------------------------------------+
+   | 8 | DPI | rte_rawdev                                                   |
+   +---+-----+--------------------------------------------------------------+
 
 PF0 is called the administrative / admin function (AF) and has exclusive
 privileges to provision RVU functional block's LFs to each of the PF/VF.
@@ -82,6 +86,23 @@ resource provisioning example where,
 2. PFx-VF1 ethdev driver bound to the first DPDK application.
 3. PFy ethdev driver, PFy-VF0 ethdev driver, PFz eventdev driver, PFm-VF0 cryptodev driver bound to the second DPDK application.
 
+LBK HW Access
+-------------
+
+Loopback HW Unit (LBK) receives packets from NIX-RX and sends packets back to NIX-TX.
+The loopback block has N channels and contains data buffering that is shared across
+all channels. The LBK HW Unit is abstracted using ethdev subsystem, Where PF0's
+VFs are exposed as ethdev device and odd-even pairs of VFs are tied together,
+that is, packets sent on odd VF end up received on even VF and vice versa.
+This would enable HW accelerated means of communication between two domains
+where even VF bound to the first domain and odd VF bound to the second domain.
+
+Typical application usage models are,
+
+#. Communication between the Linux kernel and DPDK application.
+#. Exception path to Linux kernel from DPDK application as SW ``KNI`` replacement.
+#. Communication between two different DPDK applications.
+
 OCTEON TX2 packet flow
 ----------------------
 
-- 
2.22.0