Add ARM TPIU/ITM/ETMv3 decoders

2 files changed, 156 insertions, 0 deletions

diff --git a/decoders/arm_tpiu/__init__.py b/decoders/arm_tpiu/__init__.py
new file mode 100644
index 0000000..4958df8
--- /dev/null
+++ b/decoders/arm_tpiu/__init__.py
@@ -0,0 +1,28 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2015 Petteri Aimonen <jpa@sigrok.mail.kapsi.fi>
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 2 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, write to the Free Software
+## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+##
+
+'''
+This decoder stacks on top of the 'uart' decoder and decodes the frame format
+of ARMv7m Trace Port Interface Unit. It filters the data coming from various
+trace sources (such as ARMv7m ITM and ETM blocks) into separate streams that
+can be further decoded by other PDs.
+'''
+
+from .pd import Decoder
diff --git a/decoders/arm_tpiu/pd.py b/decoders/arm_tpiu/pd.py
new file mode 100644
index 0000000..0e07eb4
--- /dev/null
+++ b/decoders/arm_tpiu/pd.py
@@ -0,0 +1,128 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2015 Petteri Aimonen <jpa@sigrok.mail.kapsi.fi>
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 2 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, write to the Free Software
+## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+##
+
+import sigrokdecode as srd
+
+class Decoder(srd.Decoder):
+    api_version = 2
+    id = 'arm_tpiu'
+    name = 'ARM TPIU'
+    longname = 'ARM Trace Port Interface Unit'
+    desc = 'Filter TPIU formatted trace data into separate data streams.'
+    license = 'gplv2+'
+    inputs = ['uart']
+    outputs = ['uart'] # Emulate uart output so that arm_itm/arm_etm can stack.
+    options = (
+        {'id': 'stream', 'desc': 'Stream index', 'default': 1},
+        {'id': 'sync_offset', 'desc': 'Initial sync offset', 'default': 0},
+    )
+    annotations = (
+        ('stream', 'Current stream'),
+        ('data', 'Stream data'),
+    )
+    annotation_rows = (
+        ('stream', 'Current stream', (0,)),
+        ('data', 'Stream data', (1,)),
+    )
+
+    def __init__(self, **kwargs):
+        self.buf = []
+        self.syncbuf = []
+        self.prevsample = 0
+        self.stream = 0
+        self.stream_ss = None
+        self.bytenum = 0
+
+    def start(self):
+        self.out_ann = self.register(srd.OUTPUT_ANN)
+        self.out_python = self.register(srd.OUTPUT_PYTHON)
+
+    def stream_changed(self, ss, stream):
+        if self.stream != stream:
+            if self.stream != 0:
+                self.put(self.stream_ss, ss, self.out_ann,
+                         [0, ["Stream %d" % self.stream, "S%d" % self.stream]])
+            self.stream = stream
+            self.stream_ss = ss
+
+    def emit_byte(self, ss, es, byte):
+        if self.stream == self.options['stream']:
+            self.put(ss, es, self.out_ann, [1, ["0x%02x" % byte]])
+            self.put(ss, es, self.out_python, ['DATA', 0, (byte, [])])
+
+    def process_frame(self, buf):
+        # Byte 15 contains the lowest bits of bytes 0, 2, ... 14.
+        lowbits = buf[15][2]
+
+        for i in range(0, 15, 2):
+            # Odd bytes can be stream ID or data.
+            delayed_stream_change = None
+            lowbit = (lowbits >> (i // 2)) & 0x01
+            if buf[i][2] & 0x01 != 0:
+                if lowbit:
+                    delayed_stream_change = buf[i][2] >> 1
+                else:
+                    self.stream_changed(buf[i][0], buf[i][2] >> 1)
+            else:
+                byte = buf[i][2] | lowbit
+                self.emit_byte(buf[i][0], buf[i][1], byte)
+
+            # Even bytes are always data.
+            if i < 14:
+                self.emit_byte(buf[i+1][0], buf[i+1][1], buf[i+1][2])
+
+            # The stream change can be delayed to occur after the data byte.
+            if delayed_stream_change is not None:
+                self.stream_changed(buf[i+1][1], delayed_stream_change)
+
+    def decode(self, ss, es, data):
+        ptype, rxtx, pdata = data
+
+        if ptype != 'DATA':
+            return
+
+        # Reset packet if there is a long pause between bytes.
+        self.byte_len = es - ss
+        if ss - self.prevsample > self.byte_len:
+            self.buf = []
+        self.prevsample = es
+
+        self.buf.append((ss, es, pdata[0]))
+        self.bytenum += 1
+
+        # Allow skipping N first bytes of the data. By adjusting the sync
+        # value, one can get initial synchronization as soon as the trace
+        # starts.
+        if self.bytenum < self.options['sync_offset']:
+            self.buf = []
+            return
+
+        # Keep separate buffer for detection of sync packets.
+        # Sync packets override everything else, so that we can regain sync
+        # even if some packets are corrupted.
+        self.syncbuf = self.syncbuf[-3:] + [pdata[0]]
+        if self.syncbuf == [0xFF, 0xFF, 0xFF, 0x7F]:
+            self.buf = []
+            self.syncbuf = []
+            return
+
+        if len(self.buf) == 16:
+            self.process_frame(self.buf)
+            self.buf = []