[dts] [DTS][PATCH 2/2] scatter: add scatter test plan

[Jingguo Fu <jingguox.fu@intel.com>]

Signed-off-by: Jingguo Fu <jingguox.fu@intel.com>
---
 test_plans/scatter_test_plan.rst | 119 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 119 insertions(+)
 create mode 100644 test_plans/scatter_test_plan.rst

diff --git a/test_plans/scatter_test_plan.rst b/test_plans/scatter_test_plan.rst
new file mode 100644
index 0000000..b1f1299
--- /dev/null
+++ b/test_plans/scatter_test_plan.rst
@@ -0,0 +1,119 @@
+.. Copyright (c) <2010, 2011>, Intel Corporation
+   All rights reserved.
+   
+   Redistribution and use in source and binary forms, with or without
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+   OF THE POSSIBILITY OF SUCH DAMAGE.
+
+=================================================
+Support of Scattered Packets by Poll Mode Drivers
+=================================================
+
+The support of scattered packets by Poll Mode Drivers consists in making
+it possible to receive and to transmit scattered multi-segments packets
+composed of multiple non-contiguous memory buffers.
+To enforce the receipt of scattered packets, the DMA rings of port RX queues
+must be configured with mbuf data buffers whose size is lower than the maximum
+frame length.
+The forwarding of scattered input packets naturally enforces the transmission
+of scattered packets by PMD transmit functions.
+
+Configuring the size of mbuf data buffers
+=========================================
+
+The size of mbuf data buffers is configured with the parameter ``--mbuf-size``
+that is supplied in the set of parameters when launching the ``testpmd``
+application.
+The default size of the mbuf data buffer is 2048 so that a full 1518-byte
+(CRC included) Ethernet frame can be stored in a mono-segment packet.
+
+Functional Tests of Scattered Packets
+=====================================
+
+Testing the support of scattered packets in Poll Mode Drivers consists in
+sending to the test machine packets whose length is greater than the size
+of mbuf data buffers used to populate the DMA rings of port RX queues.
+
+First, the receipt and the transmission of scattered packets must be tested
+with the ``CRC stripping`` option enabled, which guarantees that scattered
+packets only contain packet data.
+
+In addition, the support of scattered packets must also be performed with
+the ``CRC stripping`` option disabled, to check the special cases of scattered
+input packets whose last buffer only contains the whole CRC or part of it.
+In such cases, PMD receive functions must free the last buffer when removing
+the CRC from the packet before returning it.
+
+As a whole, the following packet lengths (CRC included) must be tested to
+check all packet memory configurations:
+
+#. packet length < mbuf data buffer size
+
+#. packet length = mbuf data buffer size
+
+#. packet length = mbuf data buffer size + 1
+
+#. packet length = mbuf data buffer size + 4
+
+#. packet length = mbuf data buffer size + 5
+
+In cases 1) and 2), the hardware RX engine stores the packet data and the CRC
+in a single buffer.
+In case 3), the hardware RX engine stores the packet data and the 3 first bytes
+of the CRC in the first buffer, and the last byte of the CRC in a second buffer.
+In case 4), the hardware RX engine stores all the packet data in the first
+buffer, and the CRC in a second buffer.
+In case 5), the hardware RX engine stores part of the packet data in the first
+buffer, and the last data byte plus the CRC in a second buffer.
+
+Prerequisites
+=============
+
+Assuming that ports ``0`` and ``1`` of the test target are directly connected
+to a Traffic Generator, launch the ``testpmd`` application with the following
+arguments::
+  
+  ./build/app/testpmd -cffffff -n 3 -- -i --rxd=1024 --txd=1024 \
+  --burst=144 --txpt=32 --txht=8 --txwt=8 --txfreet=0 --rxfreet=64 \
+  --mbcache=200 --portmask=0x3 --mbuf-size=1024
+
+The -n command is used to select the number of memory channels. It should match 
+the number of memory channels on that setup.
+
+Setting the size of the mbuf data buffer to 1024 makes 1025-bytes input packets
+(CRC included) and larger packets to be stored in two buffers by the hardware
+RX engine.
+
+Test Case: Mbuf 1024 traffic
+============================
+
+Start packet forwarding in the ``testpmd`` application with the ``start`` command.
+Send 5 packets of lengths (CRC included) 1023, 1024, 1025, 1028, and 1029.
+Check that the same amount of frames and bytes are received back by the Traffic 
+Generator from its port connected to the target's port 1.
+
-- 
2.1.0