efm32: Add JTAG definitions to EFM32 target file

This makes it possible to program newer EFM32 and EFR32 chips with
JTAG, as opposed to SWD.

Change-Id: Ia3e8c1bbc66fc1f33e8cf2087ccf0d1b4dfd74e1
Signed-off-by: Jonas Norling <jonas.norling@cyanconnode.com>
Reviewed-on: http://openocd.zylin.com/4262
Tested-by: jenkins
Reviewed-by: Fredrik Hederstierna <fredrik@hederstierna.com>
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>

tcl/target/efm32.cfg

@@ -1,5 +1,8 @@
 #
-# efm32 target
+# Silicon Labs (formerly Energy Micro) EFM32 target
+#
+# Note: All EFM32 chips have SWD support, but only newer series 1
+# chips have JTAG support.
 #
 
 source [find target/swj-dp.tcl]
@@ -21,10 +24,14 @@ if { [info exists WORKAREASIZE] } {
 if { [info exists CPUTAPID] } {
    set _CPUTAPID $CPUTAPID
 } else {
-   set _CPUTAPID 0x2ba01477
+   if { [using_jtag] } {
+      set _CPUTAPID 0x4ba00477
+   } {
+      set _CPUTAPID 0x2ba01477
+   }
 }
 
-swj_newdap $_CHIPNAME cpu -expected-id $_CPUTAPID
+swj_newdap $_CHIPNAME cpu -irlen 4 -ircapture 0x1 -irmask 0xf -expected-id $_CPUTAPID
 
 adapter_khz 1000