tcl/board: Add Arty-S7 Spartan 7 FPGA Development Board

Change-Id: I8bfe780cb67a1777d5112a68e8a9781bfe4f2038
Signed-off-by: William D. Jones <wjones@wdj-consulting.com>
Reviewed-on: http://openocd.zylin.com/4525
Reviewed-by: Robert Jordens <jordens@gmail.com>
Tested-by: jenkins
Reviewed-by: Rohit Singh <rohit91.2008@gmail.com>
Reviewed-by: Matthias Welwarsky <matthias@welwarsky.de>

tcl/board/arty_s7.cfg

@@ -0,0 +1,35 @@
+#
+# Arty S7: Spartan7 25/50 FPGA Board for Makers and Hobbyists
+#
+# https://www.xilinx.com/products/boards-and-kits/1-pnziih.html
+# https://store.digilentinc.com/arty-s7-spartan-7-fpga-board-for-makers-and-hobbyists/
+
+source [find interface/ftdi/digilent-hs1.cfg]
+
+# Xilinx Spartan7-25/50 FPGA (XC7S{25,50}-CSGA324)
+source [find cpld/xilinx-xc7.cfg]
+source [find cpld/jtagspi.cfg]
+
+adapter_khz 25000
+
+# Usage:
+#
+# Load Bitstream into FPGA:
+#    openocd -f board/arty_s7.cfg -c "init;\
+#    pld load 0 bitstream.bit;\
+#    shutdown"
+#
+# Write Bitstream to Flash:
+#    openocd -f board/arty_s7.cfg -c "init;\
+#    jtagspi_init 0 bscan_spi_xc7s??.bit;\
+#    jtagspi_program bitstream.bin 0;\
+#    xc7s_program xc7s.tap;\
+#    shutdown"
+#
+# jtagspi flash proxies can be found at:
+# https://github.com/quartiq/bscan_spi_bitstreams
+#
+# For the Spartan 50 variant, use
+#  - https://github.com/quartiq/bscan_spi_bitstreams/raw/master/bscan_spi_xc7s50.bit
+# For the Spartan 25 variant, use
+#  - https://github.com/quartiq/bscan_spi_bitstreams/raw/master/bscan_spi_xc7s25.bit