Add JTAG configuration for ARM926 with XIO2001.

Boards like the cifX 50E have a XIO2001 PCIE to PCI bridge chip in the
scan chain together with the ARM926 CPU.

Please note that the adapter speed is set to 50kHz. This is very slow and
results in long transfer times. The hardware setup used to develop this
patch included an FTDI JTAG adapter, a "Papa Schlumpf" PCIE tester board,
a PCIE adapter board and finally a CIFX 50E. This is quite a long way for
a JTAG signal. In this setup 100kHz was already too fast.

plugins/romloader/jtag/openocd/tcl/jtag_detect_init.tcl

@@ -279,12 +279,13 @@ proc probe_interface {} {
 # ###################################################################
 
 set KNOWN_CPUS {
-	{ "netX_ARM966"    probe_cpu_netx_arm966 }
-	{ "netX_ARM926"    probe_cpu_netx_arm926 }
-	{ "netX4000_R7"    probe_cpu_netx4000_r7 }
-	{ "netX90_MPW_COM" probe_cpu_netx90_mpw_com }
-	{ "netX90_COM"     probe_cpu_netx90_com }
-	{ "netIOL"         probe_cpu_netiol }
+	{ "netX_ARM966"        probe_cpu_netx_arm966 }
+	{ "XIO2001_netXARM926" probe_cpu_xio2001_netx_arm926 }
+	{ "netX_ARM926"        probe_cpu_netx_arm926 }
+	{ "netX4000_R7"        probe_cpu_netx4000_r7 }
+	{ "netX90_MPW_COM"     probe_cpu_netx90_mpw_com }
+	{ "netX90_COM"         probe_cpu_netx90_com }
+	{ "netIOL"             probe_cpu_netiol }
 }
 
 proc probe_cpu_netx_arm966 {} {
@@ -348,6 +349,36 @@ proc probe_cpu_netx_arm926 {} {
 	}
 }
 
+proc probe_cpu_xio2001_netx_arm926 {} {
+	echo "probe_cpu XIO2001 with netX_ARM926"
+
+	global SC_CFG_RESULT
+	global __JTAG_RESET__
+
+	jtag newtap netX_ARM926 cpu -irlen 4 -ircapture 1 -irmask 0xf -expected-id 0x07926021
+	jtag newtap XIO2001 tap -irlen 5 -expected-id 0x00000000
+	jtag configure netX_ARM926.cpu -event setup { global SC_CFG_RESULT ; echo {Yay} ; set SC_CFG_RESULT {OK} }
+	jtag init
+
+	if { $SC_CFG_RESULT=={OK} } {
+		target create netX_ARM926.cpu arm926ejs -endian little -chain-position netX_ARM926.cpu
+		if { $__JTAG_RESET__==1 } {
+			netX_ARM926.cpu configure -event reset-assert { reset_assert }
+			netX_ARM926.cpu configure -event reset-deassert-post { reset_deassert_post }
+		}
+		netX_ARM926.cpu configure -event reset-init { echo {netX_ARM926.cpu  reset-init event}; halt }
+		netX_ARM926.cpu configure -work-area-phys 0x0380 -work-area-size 0x0080 -work-area-backup 1
+
+		global strTarget
+		set strTarget XIO2001_ARM926
+
+		global ADAPTER_MAX_KHZ
+		set ADAPTER_MAX_KHZ 50
+	} else {
+		return -code error "Failed to probe XIO with netX_ARM926."
+	}
+}
+
 proc probe_cpu_netx4000_r7 {} {
 	echo "probe_cpu netX4000_R7"