xilinx-dna.cfg: generic tools for reading Xilinx Device DNA

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

This commit adds generic support for reading the Xilinx Spartan 6 and 7
Series (Kintex, Artix, Ultrascale) Device DNA. The code is similar to
the function in fpga/xilinx-xc6s.cfg for Spartan 6 but the register
addresses are different and the logic has been simplified.

The code was not placed in xilinx-xc7.cfg. The approach of defining taps
in the same file as library code to use them is fundamentally broken on
boards that have more than one FPGA or other chips. This commit (like
the addition of support for Xilinx XADC) starts to remedy that by
splitting library code from board-specific fixed definitions.

The support code is sourced in the Kasli and KC705 board support files
as it was tested on these boards.

Change-Id: Iba559c7c1b7e93e1270535fd9e6650007f3794da
Signed-off-by: Robert Jordens <jordens@gmail.com>
Reviewed-on: http://openocd.zylin.com/4396
Tested-by: jenkins
Reviewed-by: Matthias Welwarsky <matthias@welwarsky.de>

tcl/board/kasli.cfg

@@ -12,3 +12,4 @@ adapter_khz 25000
 source [find cpld/xilinx-xc7.cfg]
 source [find cpld/jtagspi.cfg]
 source [find fpga/xilinx-xadc.cfg]
+source [find fpga/xilinx-dna.cfg]

tcl/board/kc705.cfg

@@ -4,6 +4,7 @@ source [find interface/ftdi/digilent-hs1.cfg]
 source [find cpld/xilinx-xc7.cfg]
 source [find cpld/jtagspi.cfg]
 source [find fpga/xilinx-xadc.cfg]
+source [find fpga/xilinx-dna.cfg]
 adapter_khz 25000
 
 # example command to write bitstream, soft-cpu bios and runtime:

tcl/fpga/xilinx-dna.cfg

@@ -0,0 +1,43 @@
+proc xilinx_dna_addr {chip} {
+	array set addrs {
+		Spartan6 0x30
+		Series7 0x17
+	}
+	return $addrs($chip)
+}
+
+# Get the "Device DNA".
+# Most Xilinx FPGA devices contain an embedded, unique device identifier.
+# The identifier is nonvolatile, permanently programmed into
+# the FPGA, and is unchangeable providing a great serial / tracking number.
+# This function returns the DNA as a 64 bit integer with the 7 LSBs zeroed.
+# This is compatible with the FUSE DNA which contains all 64 bits.
+proc xilinx_get_dna {tap chip} {
+	set XC7_ISC_ENABLE 0x10
+	set XC7_ISC_DISABLE 0x16
+	set XC7_ISC_DNA [xilinx_dna_addr $chip]
+
+	irscan $tap $XC7_ISC_ENABLE
+	runtest 64
+	irscan $tap $XC7_ISC_DNA
+	scan [drscan $tap 32 0 32 0] "%08x %08x" hi lo
+	runtest 64
+	irscan $tap $XC7_ISC_DISABLE
+	runtest 64
+	# openocd interprets DR scans as LSB first, bit-reverse it
+	return [scan [string reverse [format "%032b%032bb0" $lo $hi]] "%i"]
+}
+
+# Print out the "Device DNA" in the same format that impact uses.
+proc xilinx_print_dna {dna} {
+	set dna [expr $dna >> 64 - 57]
+	echo [format "DNA = %057b (0x%016x)" $dna $dna]
+}
+
+proc xc7_get_dna {tap} {
+	return [xilinx_get_dna $tap Series7]
+}
+
+proc xc6s_get_dna {tap} {
+	return [xilinx_get_dna $tap Spartan6]
+}