From 289234b1024c71d6e61230f5938c477b4c7f4e8c Mon Sep 17 00:00:00 2001
From: Florent Kermarrec <florent@enjoy-digital.fr>
Date: Sat, 28 Nov 2020 08:58:04 +0100
Subject: [PATCH] build/lattice: add bit_to_svf script from Project Trellis to
 allow using OpenOCD with Diamond.

---
 litex/build/lattice/bit_to_svf.py | 109 ++++++++++++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 litex/build/lattice/bit_to_svf.py

diff --git a/litex/build/lattice/bit_to_svf.py b/litex/build/lattice/bit_to_svf.py
new file mode 100644
index 000000000..f702751fc
--- /dev/null
+++ b/litex/build/lattice/bit_to_svf.py
@@ -0,0 +1,109 @@
+#!/usr/bin/env python3
+
+# Very basic bitstream to SVF converter
+# This file is Copyright (c) 2018 David Shah <dave@ds0.me>
+
+import sys
+import textwrap
+
+max_row_size = 100000
+
+def bitreverse(x):
+    y = 0
+    for i in range(8):
+        if (x >> (7 - i)) & 1 == 1:
+            y |= (1 << i)
+    return y
+
+def bit_to_svf(bit, svf):
+    with open(bit, 'rb') as bitf:
+        bs = bitf.read()
+        # Autodetect IDCODE from bitstream
+        idcode_cmd = bytes([0xE2, 0x00, 0x00, 0x00])
+        idcode = None
+        for i in range(len(bs) - 4):
+            if bs[i:i+4] == idcode_cmd:
+                idcode = bs[i+4] << 24
+                idcode |= bs[i+5] << 16
+                idcode |= bs[i+6] << 8
+                idcode |= bs[i+7]
+                break
+        if idcode is None:
+            print("Failed to find IDCODE in bitstream, check bitstream is valid")
+            sys.exit(1)
+        print("IDCODE in bitstream is 0x%08x" % idcode)
+        bitf.seek(0)
+        with open(svf, 'w') as svf:
+            print("""
+    HDR	0;
+    HIR	0;
+    TDR	0;
+    TIR	0;
+    ENDDR	DRPAUSE;
+    ENDIR	IRPAUSE;
+    STATE	IDLE;
+            """, file=svf)
+            print("""
+    SIR	8	TDI  (E0);
+    SDR	32	TDI  (00000000)
+            TDO  ({:08X})
+            MASK (FFFFFFFF);
+            """.format(idcode), file=svf)
+            print("""
+    SIR	8	TDI  (1C);
+    SDR	510	TDI  (3FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
+                 FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF);
+
+    SIR	8	TDI  (C6);
+    SDR	8	TDI  (00);
+    RUNTEST	IDLE	2 TCK	1.00E-02 SEC;
+
+    SIR	8	TDI  (3C);
+    SDR	32	TDI  (00000000)
+            TDO  (00000000)
+            MASK (0000B000);
+
+    SIR	8	TDI  (46);
+    SDR	8	TDI  (01);
+    RUNTEST	IDLE	2 TCK	1.00E-02 SEC;
+
+    SIR	8	TDI  (7A);
+    RUNTEST	IDLE	2 TCK	1.00E-02 SEC;
+
+            """, file=svf)
+            while True:
+                chunk = bitf.read(max_row_size//8)
+                if not chunk:
+                    break
+                # Convert chunk to bit-reversed hex
+                br_chunk = [bitreverse(x) for x in chunk]
+                hex_chunk = ["{:02X}".format(x) for x in reversed(br_chunk)]
+                print("\n".join(textwrap.wrap("SDR {} TDI ({});".format(8*len(chunk), "".join(hex_chunk)), 100)), file=svf)
+
+            print("""
+    SIR	8	TDI  (FF);
+    RUNTEST	IDLE	100 TCK	1.00E-02 SEC;
+
+
+    SIR	8	TDI  (C0);
+    RUNTEST	IDLE	2 TCK	1.00E-03 SEC;
+    SDR	32	TDI  (00000000)
+            TDO  (00000000)
+            MASK (FFFFFFFF);
+
+    ! Shift in ISC DISABLE(0x26) instruction
+    SIR	8	TDI  (26);
+    RUNTEST	IDLE	2 TCK	2.00E-01 SEC;
+    ! Shift in BYPASS(0xFF) instruction
+    SIR	8	TDI  (FF);
+    RUNTEST	IDLE	2 TCK	1.00E-03 SEC;
+
+    ! Shift in LSC_READ_STATUS(0x3C) instruction
+    SIR	8	TDI  (3C);
+    SDR	32	TDI  (00000000)
+            TDO  (00000100)
+            MASK (00002100);
+            """, file=svf)
+
+if __name__ == "__main__":
+    bit_to_svf(sys.argv[1], sys.argv[2])
\ No newline at end of file