cfg: add TI am43xx devices

This adds support for the am43xx SoC and the AM437x GP EVM and AM438x
ePOS EVM.

Change-Id: I09cbb09072f38e0e08fdd520dedb6e67d45056be
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Tom Rini <trini@ti.com>
Reviewed-on: http://openocd.zylin.com/2047


Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>

tcl/board/ti_am43xx_evm.cfg

+# Works on both AM437x GP EVM and AM438x ePOS EVM
+
+# The JTAG interface is built directly on the board.
+source [find interface/ftdi/xds100v2.cfg]
+
+adapter_khz 16000
+
+source [find target/am437x.cfg]
+
+reset_config trst_and_srst

tcl/target/am437x.cfg

+source [find target/icepick.cfg]
+
+if { [info exists CHIPNAME] } {
+   set _CHIPNAME $CHIPNAME
+} else {
+   set _CHIPNAME am437x
+}
+
+#
+# M3 DAP
+#
+if { [info exists M3_DAP_TAPID] } {
+	set _M3_DAP_TAPID $M3_DAP_TAPID
+} else {
+	set _M3_DAP_TAPID 0x4b6b902f
+}
+jtag newtap $_CHIPNAME m3_dap -irlen 4 -ircapture 0x1 -irmask 0xf -expected-id $_M3_DAP_TAPID -disable
+jtag configure $_CHIPNAME.m3_dap -event tap-enable "icepick_d_tapenable $_CHIPNAME.jrc 11"
+
+#
+# Cortex A9 DAP
+#
+if { [info exists DAP_TAPID] } {
+   set _DAP_TAPID $DAP_TAPID
+} else {
+   set _DAP_TAPID 0x4b6b902f
+}
+jtag newtap $_CHIPNAME dap -irlen 4 -ircapture 0x1 -irmask 0xf -expected-id $_DAP_TAPID -disable
+jtag configure $_CHIPNAME.dap -event tap-enable "icepick_d_tapenable $_CHIPNAME.jrc 12"
+
+#
+# ICEpick-D (JTAG route controller)
+#
+if { [info exists JRC_TAPID] } {
+   set _JRC_TAPID $JRC_TAPID
+} else {
+   set _JRC_TAPID 0x0b98c02f
+}
+jtag newtap $_CHIPNAME jrc -irlen 6 -ircapture 0x1 -irmask 0x3f -expected-id $_JRC_TAPID -ignore-version
+jtag configure $_CHIPNAME.jrc -event setup "jtag tapenable $_CHIPNAME.dap"
+# some TCK tycles are required to activate the DEBUG power domain
+jtag configure $_CHIPNAME.jrc -event post-reset "runtest 100"
+
+#
+# Cortex A9 target
+#
+set _TARGETNAME $_CHIPNAME.cpu
+target create $_TARGETNAME cortex_a -chain-position $_CHIPNAME.dap
+
+# SRAM: 64K at 0x4030.0000; use the first 16K
+$_TARGETNAME configure -work-area-phys 0x40300000 -work-area-size 0x4000