tcl: add hi3798 target and Tocoding Poplar board config

This config covers the 4x Cortex A53 CPUs. A custom connector
is required from J14 to standard ARM JTAG on v1 boards. However
v2 hardware should have a standard FTSH-105-01-L-DV connector.

Pinmuxing code to enable JTAG pins is included in l-loader-poplar
repository, so board is flashed with open source code, JTAG
is available at very early boot. Alternatively the following
pokes can be issued from U-Boot to enable JTAG (e.g. to debug
hisilicon SDK).

mw 0xf8a210ec 0x130;
mw 0xf8a210f0 0x130;
mw 0xf8a210f4 0x130;
mw 0xf8a210f8 0x130;
mw 0xf8a210fc 0x130;
mw 0xf8a21100 0x130;

Change-Id: I2b83dfcb3dc5461c1620f94dd99aa7b31fdda59b
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Reviewed-on: http://openocd.zylin.com/4161
Tested-by: jenkins
Reviewed-by: Jiri Kastner <cz172638@gmail.com>
Reviewed-by: Paul Fertser <fercerpav@gmail.com>

tcl/board/tocoding_poplar.cfg

@@ -0,0 +1,28 @@
+#
+# board configuration for Tocoding Poplar
+#
+
+# board does not feature anything but JTAG
+transport select jtag
+
+adapter_khz 10000
+
+# SRST-only reset configuration
+reset_config srst_only srst_push_pull
+
+source [find tcl/target/hi3798.cfg]
+
+# halt the cores when gdb attaches
+${_TARGETNAME}0 configure -event gdb-attach "halt"
+
+# make sure the default target is the boot core
+targets ${_TARGETNAME}0
+
+proc core_up { args } {
+	global _TARGETNAME
+
+	# examine remaining cores
+	foreach _core [set args] {
+		${_TARGETNAME}$_core arp_examine
+	}
+}