usb_power_delivery: enforce check order for start-of-packet sequences

[libsigrokdecode.git] / decoders / usb_power_delivery / pd.py

diff --git a/decoders/usb_power_delivery/pd.py b/decoders/usb_power_delivery/pd.py
index e8d0afb90b6e97761539b12458b15f4eccad3c4c..c182498c025f5535cf758013699d35694485e2ab 100644 (file)
--- a/decoders/usb_power_delivery/pd.py
+++ b/decoders/usb_power_delivery/pd.py
@@ -14,8 +14,7 @@
 ## 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
+## along with this program; if not, see <http://www.gnu.org/licenses/>.
 ##
 
 import sigrokdecode as srd
@@ -102,14 +101,23 @@ EOP = 0x16
 SYNC_CODES = [SYNC1, SYNC2, SYNC3]
 HRST_CODES = [RST1, RST1, RST1, RST2]
 
+SOP_SEQUENCES = [
+    (SYNC1, SYNC1, SYNC1, SYNC2),
+    (SYNC1, SYNC1, SYNC3, SYNC3),
+    (SYNC1, SYNC3, SYNC1, SYNC3),
+    (SYNC1, RST2,  RST2,  SYNC3),
+    (SYNC1, RST2,  SYNC3, SYNC2),
+    (RST1,  SYNC1, RST1,  SYNC3),
+    (RST1,  RST1,  RST1,   RST2),
+]
 START_OF_PACKETS = {
-    (SYNC1, SYNC1, SYNC1, SYNC2): 'SOP',
-    (SYNC1, SYNC1, SYNC3, SYNC3): "SOP'",
-    (SYNC1, SYNC3, SYNC1, SYNC3): 'SOP"',
-    (SYNC1, RST2,  RST2,  SYNC3): "SOP' Debug",
-    (SYNC1, RST2,  SYNC3, SYNC2): 'SOP" Debug',
-    (RST1,  SYNC1, RST1,  SYNC3): 'Cable Reset',
-    (RST1,  RST1,  RST1,   RST2): 'Hard Reset',
+    SOP_SEQUENCES[0]: 'SOP',
+    SOP_SEQUENCES[1]: "SOP'",
+    SOP_SEQUENCES[2]: 'SOP"',
+    SOP_SEQUENCES[3]: "SOP' Debug",
+    SOP_SEQUENCES[4]: 'SOP" Debug',
+    SOP_SEQUENCES[5]: 'Cable Reset',
+    SOP_SEQUENCES[6]: 'Hard Reset',
 }
 
 SYM_NAME = [
@@ -178,8 +186,11 @@ VDM_CMDS = {
 }
 VDM_ACK = ['REQ', 'ACK', 'NAK', 'BSY']
 
+class SamplerateError(Exception):
+    pass
+
 class Decoder(srd.Decoder):
-    api_version = 2
+    api_version = 3
     id = 'usb_power_delivery'
     name = 'USB PD'
     longname = 'USB Power Delivery'
@@ -226,7 +237,7 @@ class Decoder(srd.Decoder):
         op_ma = ((rdo >> 10) & 0x3ff) * 10
         max_ma = (rdo & 0x3ff) * 10
         flags = ''
-        for f in RDO_FLAGS.keys():
+        for f in sorted(RDO_FLAGS.keys(), reverse = True):
             if rdo & f:
                 flags += ' ' + RDO_FLAGS[f]
         return '[%d]%d/%d mA%s' % (pos, op_ma, max_ma, flags)
@@ -250,7 +261,7 @@ class Decoder(srd.Decoder):
         else:
             p = ''
         flags = ''
-        for f in PDO_FLAGS.keys():
+        for f in sorted(PDO_FLAGS.keys(), reverse = True):
             if pdo & f:
                 flags += ' ' + PDO_FLAGS[f]
         return '%s%s%s' % (PDO_TYPE[t], p, flags)
@@ -274,7 +285,7 @@ class Decoder(srd.Decoder):
         else:
             p = ''
         flags = ''
-        for f in PDO_FLAGS.keys():
+        for f in sorted(PDO_FLAGS.keys(), reverse = True):
             if pdo & f:
                 flags += ' ' + PDO_FLAGS[f]
         return '%s%s%s' % (PDO_TYPE[t], p, flags)
@@ -401,7 +412,7 @@ class Decoder(srd.Decoder):
     def find_corrupted_sop(self, k):
         # Start of packet are valid even if they have only 3 correct symbols
         # out of 4.
-        for seq in START_OF_PACKETS.keys():
+        for seq in SOP_SEQUENCES:
             if [k[i] == seq[i] for i in range(len(k))].count(True) >= 3:
                 return START_OF_PACKETS[seq]
         return None
@@ -410,7 +421,7 @@ class Decoder(srd.Decoder):
         for i in range(len(self.bits) - 19):
             k = (self.get_sym(i, rec=False), self.get_sym(i+5, rec=False),
                  self.get_sym(i+10, rec=False), self.get_sym(i+15, rec=False))
-            sym = START_OF_PACKETS[k] if k in START_OF_PACKETS else None
+            sym = START_OF_PACKETS.get(k, None)
             if not sym:
                 sym = self.find_corrupted_sop(k)
             # We have an interesting symbol sequence
@@ -436,13 +447,14 @@ class Decoder(srd.Decoder):
         self.putwarn('No start of packet found', 'XXX')
         return -1   # No Start Of Packet
 
-    def __init__(self, **kwargs):
+    def __init__(self):
+        self.reset()
+
+    def reset(self):
         self.samplerate = None
         self.idx = 0
         self.packet_seq = 0
-        self.samplenum = 0
         self.previous = 0
-        self.oldpins = [0]
         self.startsample = None
         self.bits = []
         self.edges = []
@@ -468,8 +480,6 @@ class Decoder(srd.Decoder):
         )
 
     def us2samples(self, us):
-        if self.samplerate is None:
-            raise Exception('Need the samplerate.')
         return int(us * self.samplerate / 1000000)
 
     def decode_packet(self):
@@ -524,17 +534,13 @@ class Decoder(srd.Decoder):
         bitrate = self.samplerate*len(self.bits) / float(es - ss)
         self.put(es, ss, self.out_bitrate, int(bitrate))
         # Raw binary data (BMC decoded)
-        self.put(es, ss, self.out_binary, (0, bytes(self.bits)))
-
-    def decode(self, ss, es, data):
-        if self.samplerate is None:
-            raise Exception('Cannot decode without samplerate.')
-        for (self.samplenum, pins) in data:
-            # find edges ...
-            if self.oldpins == pins:
-                continue
+        self.put(es, ss, self.out_binary, [0, bytes(self.bits)])
 
-            self.oldpins, (cc, ) = pins, pins
+    def decode(self):
+        if not self.samplerate:
+            raise SamplerateError('Cannot decode without samplerate.')
+        while True:
+            self.wait({0: 'e'})
 
             # First sample of the packet, just record the start date
             if not self.startsample: