bcm281xx: Add bcm281xx SoC and bcm28155_ap board

Add support for Broadcom's dual A9 mobile SoC and its reference board.

Change-Id: Ia145b120043bddc89c44726066023154ae390788
Signed-off-by: Tim Kryger <tim.kryger@linaro.org>
Reviewed-on: http://openocd.zylin.com/1926
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>

tcl/board/bcm28155_ap.cfg

@@ -0,0 +1,9 @@
+# BCM28155_AP
+
+adapter_khz 20000
+
+set CHIPNAME bcm28155
+source [find target/bcm281xx.cfg]
+
+reset_config trst_and_srst
+

tcl/target/bcm281xx.cfg

@@ -0,0 +1,33 @@
+# BCM281xx
+
+if { [info exists CHIPNAME] } {
+	set  _CHIPNAME $CHIPNAME
+} else {
+	set  _CHIPNAME bcm281xx
+}
+
+
+# Main CPU DAP
+if { [info exists DAP_TAPID] } {
+	set _DAP_TAPID $DAP_TAPID
+} else {
+	set _DAP_TAPID 0x4ba00477
+}
+
+jtag newtap $_CHIPNAME dap -expected-id $_DAP_TAPID -irlen 4
+
+
+# Dual Cortex A9s
+set _TARGETNAME0 $_CHIPNAME.cpu0
+set _TARGETNAME1 $_CHIPNAME.cpu1
+
+target create $_TARGETNAME0 cortex_a -chain-position $_CHIPNAME.dap -coreid 0 -dbgbase 0x3fe10000
+target create $_TARGETNAME1 cortex_a -chain-position $_CHIPNAME.dap -coreid 1 -dbgbase 0x3fe12000
+target smp $_TARGETNAME0 $_TARGETNAME1
+
+$_TARGETNAME0 configure -event gdb-attach {
+	cortex_a dbginit
+}
+$_TARGETNAME1 configure -event gdb-attach {
+	cortex_a dbginit
+}