Add an MDIO/SMI decoder.

2 files changed, 289 insertions, 0 deletions

diff --git a/decoders/mdio/__init__.py b/decoders/mdio/__init__.py
new file mode 100644
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+++ b/decoders/mdio/__init__.py
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+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2014 Aurelien Jacobs <aurel@gnuage.org>
+##
+## 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
+##
+
+'''
+The MDIO (Management Data Input/Output) protocol decoder supports the
+MII Management serial bus, with a clock line (MDC) and a bi-directional
+data line (MDIO).
+
+MDIO is also known as SMI (Serial Management Interface).
+'''
+
+from .pd import Decoder
diff --git a/decoders/mdio/pd.py b/decoders/mdio/pd.py
new file mode 100644
index 0000000..bb1f53f
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+++ b/decoders/mdio/pd.py
@@ -0,0 +1,260 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2014 Aurelien Jacobs <aurel@gnuage.org>
+##
+## 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 = 'mdio'
+    name = 'MDIO'
+    longname = 'Management Data Input/Output'
+    desc = 'Half-duplex sync serial bus for MII management between MAC and PHY.'
+    license = 'gplv2+'
+    inputs = ['logic']
+    outputs = ['mdio']
+    channels = (
+        {'id': 'mdc', 'name': 'MDC', 'desc': 'Clock'},
+        {'id': 'mdio', 'name': 'MDIO', 'desc': 'Data'},
+    )
+    annotations = (
+        ('mdio-data', 'MDIO data'),
+        ('mdio-bits', 'MDIO bits'),
+        ('errors', 'Human-readable errors'),
+    )
+    annotation_rows = (
+        ('mdio-data', 'MDIO data', (0,)),
+        ('mdio-bits', 'MDIO bits', (1,)),
+        ('other', 'Other', (2,)),
+    )
+
+    def __init__(self):
+        self.oldmdc = 0
+        self.ss_block = -1
+        self.samplenum = -1
+        self.oldpins = None
+        self.reset_decoder_state()
+
+    def start(self):
+        self.out_python = self.register(srd.OUTPUT_PYTHON)
+        self.out_ann = self.register(srd.OUTPUT_ANN)
+
+    def putw(self, data):
+        self.put(self.ss_block, self.samplenum, self.out_ann, data)
+
+    def putbit(self, mdio, start, stop):
+        # Bit annotations.
+        self.put(start, stop, self.out_ann, [1, ['%d' % mdio]])
+
+    def putdata(self):
+        # FIXME: Only pass data, no bits.
+        # Pass MDIO bits and then data to the next PD up the stack.
+        ss, es = self.mdiobits[-1][1], self.mdiobits[0][2]
+
+        # self.put(ss, es, self.out_python, ['BITS', self.mdiobits])
+        self.put(ss, es, self.out_python, ['DATA', self.mdiodata])
+
+        # Bit annotations.
+        for bit in self.mdiobits:
+            self.put(bit[1], bit[2], self.out_ann, [1, ['%d' % bit[0]]])
+
+        # Error annotation if an error happened.
+        if self.error:
+            self.put(self.ss_bit, self.es_error, self.out_ann, [2, [self.error]])
+            return
+
+        op = 'READ' if self.operation else 'WRITE'
+
+        # Dataword annotations.
+        if self.ss_preamble != -1:
+            self.put(self.ss_preamble, self.ss_start, self.out_ann, [0, ['PREAMBLE']])
+        self.put(self.ss_start, self.ss_operation, self.out_ann, [0, ['START']])
+        self.put(self.ss_operation, self.ss_phy, self.out_ann, [0, [op]])
+        self.put(self.ss_phy, self.ss_reg, self.out_ann, [0, ['PHY: %d' % self.phy]])
+        self.put(self.ss_reg, self.ss_turnaround, self.out_ann, [0, ['REG: %d' % self.reg]])
+        self.put(self.ss_turnaround, self.ss_data, self.out_ann, [0, ['TURNAROUND']])
+        self.put(self.ss_data, self.es_data, self.out_ann, [0, ['DATA: %04X' % self.data]])
+
+    def reset_decoder_state(self):
+        self.mdiodata = 0
+        self.mdiobits = []
+        self.bitcount = 0
+        self.ss_preamble = -1
+        self.ss_start = -1
+        self.ss_operation = -1
+        self.ss_phy = -1
+        self.ss_reg = -1
+        self.ss_turnaround = -1
+        self.ss_data = -1
+        self.phy = 0
+        self.phy_bits = 0
+        self.reg = 0
+        self.reg_bits = 0
+        self.data = 0
+        self.data_bits = 0
+        self.state = 'PREAMBLE'
+        self.error = None
+
+    def parse_preamble(self, mdio):
+        if self.ss_preamble == -1:
+            self.ss_preamble = self.samplenum
+        if mdio != 1:
+            self.error = 'Invalid preamble: could not find 32 consecutive bits set to 1'
+            self.state = 'ERROR'
+        elif self.bitcount == 31:
+            self.state = 'START'
+
+    def parse_start(self, mdio):
+        if self.ss_start == -1:
+            if mdio != 0:
+                self.error = 'Invalid start bits: should be 01'
+                self.state = 'ERROR'
+            else:
+                self.ss_start = self.samplenum
+        else:
+            if mdio != 1:
+                self.error = 'Invalid start bits: should be 01'
+                self.state = 'ERROR'
+            else:
+                self.state = 'OPERATION'
+
+    def parse_operation(self, mdio):
+        if self.ss_operation == -1:
+            self.ss_operation = self.samplenum
+            self.operation = mdio
+        else:
+            if mdio == self.operation:
+                self.error = 'Invalid operation bits'
+                self.state = 'ERROR'
+            else:
+                self.state = 'PHY'
+
+    def parse_phy(self, mdio):
+        if self.ss_phy == -1:
+            self.ss_phy = self.samplenum
+        self.phy_bits += 1
+        self.phy |= mdio << (5 - self.phy_bits)
+        if self.phy_bits == 5:
+            self.state = 'REG'
+
+    def parse_reg(self, mdio):
+        if self.ss_reg == -1:
+            self.ss_reg = self.samplenum
+        self.reg_bits += 1
+        self.reg |= mdio << (5 - self.reg_bits)
+        if self.reg_bits == 5:
+            self.state = 'TURNAROUND'
+
+    def parse_turnaround(self, mdio):
+        if self.ss_turnaround == -1:
+            if self.operation == 0 and mdio != 1:
+                self.error = 'Invalid turnaround bits'
+                self.state = 'ERROR'
+            else:
+                self.ss_turnaround = self.samplenum
+        else:
+            if mdio != 0:
+                self.error = 'Invalid turnaround bits'
+                self.state = 'ERROR'
+            else:
+                self.state = 'DATA'
+
+    def parse_data(self, mdio):
+        if self.ss_data == -1:
+            self.ss_data = self.samplenum
+        self.data_bits += 1
+        self.data |= mdio << (16 - self.data_bits)
+        if self.data_bits == 16:
+            self.es_data = self.samplenum + int((self.samplenum - self.ss_data) / 15)
+            self.state = 'DONE'
+
+    def parse_error(self, mdio):
+        if self.bitcount == 63:
+            self.es_error = self.samplenum + int((self.samplenum - self.ss_bit) / 63)
+            self.state = 'DONE'
+
+    def handle_bit(self, mdio):
+        # If this is the first bit of a command, save its sample number.
+        if self.bitcount == 0:
+            self.ss_bit = self.samplenum
+            # No preamble?
+            if mdio == 0:
+                self.state = 'START'
+
+        # Guesstimate the endsample for this bit (can be overridden below).
+        es = self.samplenum
+        if self.bitcount > 0:
+            es += self.samplenum - self.mdiobits[0][1]
+
+        self.mdiobits.insert(0, [mdio, self.samplenum, es])
+
+        if self.bitcount > 0:
+            self.bitsamples = (self.samplenum - self.ss_bit) / self.bitcount
+            self.mdiobits[1][2] = self.samplenum
+
+        if self.state == 'PREAMBLE':
+            self.parse_preamble(mdio)
+        elif self.state == 'START':
+            self.parse_start(mdio)
+        elif self.state == 'OPERATION':
+            self.parse_operation(mdio)
+        elif self.state == 'PHY':
+            self.parse_phy(mdio)
+        elif self.state == 'REG':
+            self.parse_reg(mdio)
+        elif self.state == 'TURNAROUND':
+            self.parse_turnaround(mdio)
+        elif self.state == 'DATA':
+            self.parse_data(mdio)
+        elif self.state == 'ERROR':
+            self.parse_error(mdio)
+
+        self.bitcount += 1
+        if self.state == 'DONE':
+            self.putdata()
+            self.reset_decoder_state()
+
+    def find_mdc_edge(self, mdc, mdio):
+        # Output the current error annotation if the clock stopped running
+        if self.state == 'ERROR' and self.samplenum - self.clocksample > (1.5 * self.bitsamples):
+            self.es_error = self.clocksample + int((self.clocksample - self.ss_bit) / self.bitcount)
+            self.putdata()
+            self.reset_decoder_state()
+
+        # Ignore sample if the clock pin hasn't changed.
+        if mdc == self.oldmdc:
+            return
+
+        self.oldmdc = mdc
+
+        if mdc == 0:   # Sample on rising clock edge.
+            return
+
+        # Found the correct clock edge, now get/handle the bit(s).
+        self.clocksample = self.samplenum
+        self.handle_bit(mdio)
+
+    def decode(self, ss, es, data):
+        for (self.samplenum, pins) in data:
+            # Ignore identical samples early on (for performance reasons).
+            if self.oldpins == pins:
+                continue
+            self.oldpins, (mdc, mdio) = pins, pins
+
+            self.find_mdc_edge(mdc, mdio)