xc7: lite sata add third party code for VexRiscV and improve docs

Signed-off-by: Alessandro Comodi <acomodi@antmicro.com>

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "third_party/projf-explore"]
 	path = third_party/projf-explore
 	url = https://github.com/projf/projf-explore.git
+[submodule "third_party/vexriscv-verilog"]
+	path = third_party/vexriscv-verilog
+	url = https://github.com/m-labs/VexRiscv-verilog

third_party/vexriscv-verilog

@@ -0,0 +1 @@
+Subproject commit 2e4f43d72404a986c9d7251d9d543cf7aef077bc

xc7/linux_litex_demo/Makefile

@@ -1,7 +1,7 @@
 current_dir := ${CURDIR}
 TOP := top
 SOURCES := ${current_dir}/baselitex_arty.v \
-           ${current_dir}/VexRiscv_Linux.v
+           ${current_dir}/../../third_party/vexriscv-verilog/VexRiscv_Linux.v
 
 PCF := ${current_dir}/arty.pcf
 SDC := ${current_dir}/arty.sdc

xc7/litex_sata_demo/Makefile

@@ -1,7 +1,7 @@
 current_dir := ${CURDIR}
 TOP := top
 SOURCES := ${current_dir}/litesata.v \
-           ${current_dir}/VexRiscv.v
+           ${current_dir}/../../third_party/vexriscv-verilog/VexRiscv.v
 
 XDC := ${current_dir}/nexys_video.xdc
 

xc7/litex_sata_demo/README.rst

@@ -2,8 +2,10 @@ LiteX SATA demo
 ~~~~~~~~~~~~~~~
 
 This example design features a Litex SoC based around VexRiscv soft
-CPU. It also includes a DDR controller and a SATA core . To build the litex SATA example,
-run the following commands:
+CPU. It also includes a DDR controller and a SATA core.
+
+The design targets the `Nexys Video <https://digilent.com/reference/programmable-logic/nexys-video/start>`_ board, mounting an Artix-7 200T FPGA,
+and the `FMC adapter board <https://github.com/antmicro/fmc-sata-adapter>`_, mounting an M.2 SSD.
 
 To build the litex SATA demo example, first re-navigate to the directory that contains examples for Xilinx 7-Series FPGAs. Then depending on your hardware, run:
 
@@ -19,3 +21,18 @@ At completion, the bitstreams are located in the build directory:
 
    litex_sata_demo/build/<board>
 
+To generate the source files for this test, the following packages were used:
+
+===========================================================  ========================================
+Repo URL                                                     SHA
+===========================================================  ========================================
+`LiteX <https://github.com/enjoy-digital/litex>`_            95b310ee0f0d9e78e00eb32b71324b25265da4f4
+`LiteSATA <https://github.com/enjoy-digital/litesata>`_      fae9f8d5b7b6d4c6a0a93b496bd15db5201d14f7
+`LiteDRAM <https://github.com/enjoy-digital/litedram>`_      2c60861929a317af697267d6219da43d10dcf1fa
+`LiteICLink <https://github.com/enjoy-digital/liteiclink>`_  0980a7cf4ffcb0b69a84fa0343a66180408b2a91
+`LiteX Boards <https://github.com/litex-hub/litex-boards>`_  ea58ef94a784308ae024a1d201d603bc8459a590
+`migen <https://github.com/m-labs/migen>`_                   c50ecdebd0e93c90ff44ca2e13d9f55fa97947d5
+===========================================================  ========================================
+
+The generated verilog design file (litesata.v) contains a couple of fixes to properly work with the Yosys+VPR flow.
+The fixes are around the GTP high speed transceivers hard blocks.