From 3edb15784eca5bdd7981f7889909e273ad9775d1 Mon Sep 17 00:00:00 2001
From: Tim 'mithro' Ansell <mithro@mithis.com>
Date: Sun, 27 Sep 2015 20:09:38 +1000
Subject: [PATCH] tcl: Support for reading "Device DNA" from Spartan 6 devices.

Most Xilinx FPGA devices contain an embedded, unique device identifier
called the "Device DNA". The identifier is nonvolatile, permanently
programmed into the FPGA, and is unchangeable providing a great serial
/ tracking number.

Debugging was done in https://github.com/timvideos/HDMI2USB/issues/36

Change-Id: Iad03eafb40887f0321a4dc22858a7c3bf37a12b3
Signed-off-by: Tim 'mithro' Ansell <mithro@mithis.com>
Reviewed-on: http://openocd.zylin.com/2960
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>
---
 tcl/cpld/xilinx-xc6s.cfg | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/tcl/cpld/xilinx-xc6s.cfg b/tcl/cpld/xilinx-xc6s.cfg
index b705ea1fd..9ce7ad491 100644
--- a/tcl/cpld/xilinx-xc6s.cfg
+++ b/tcl/cpld/xilinx-xc6s.cfg
@@ -52,3 +52,39 @@ proc xc6s_program_iprog {tap} {
 	irscan $tap $XC6S_BYPASS
 	runtest 1
 }
+
+set XC6S_ISC_ENABLE 0x10
+set XC6S_ISC_DISABLE 0x16
+set XC6S_ISC_DNA 0x30
+
+# Get the "Device DNA" from the Spartan 6.
+# Most Xilinx FPGA devices contain an embedded, unique device identifier called
+# the "Device DNA". The identifier is nonvolatile, permanently programmed into
+# the FPGA, and is unchangeable providing a great serial / tracking number.
+proc xc6s_get_dna {tap} {
+	global XC6S_ISC_ENABLE XC6S_ISC_DISABLE XC6S_ISC_DNA
+	irscan $tap $XC6S_ISC_ENABLE
+	runtest 64
+	irscan $tap $XC6S_ISC_DNA
+	# Device DNA is 57 bits long, but we can only read 32bits at a time
+	# with OpenOCD.
+	set dna [drscan $tap 16 0 16 0 16 0 9 0]
+	runtest 64
+	irscan $tap $XC6S_ISC_DISABLE
+	runtest 64
+
+	# Convert the binary data into the order impact uses
+	scan $dna "%x %x %x %x" v1 v2 v3 v4
+	set bin_dna [string reverse [concat [format "%09b" $v4][format "%016b" $v3][format "%016b" $v2][format "%016b" $v1]]]
+
+	# Return a hex version of binary
+	scan [format "0b%s" $bin_dna] "%i" hex_dna
+	return $hex_dna
+}
+
+# Print out the "Device DNA" in the same format that impact uses.
+proc xc6s_print_dna {tap} {
+	set hex_dna [xc6s_get_dna $tap]
+
+	puts [format "DNA = %57b (0x%x)\n" $hex_dna $hex_dna]
+}