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

##
## This file is part of the libsigrokdecode project.
##
## Copyright (C) 2018 Jorge Solla Rubiales <jorgesolla@gmail.com>
##
## 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, see <http://www.gnu.org/licenses/>.
##

import sigrokdecode as srd
from .protocoldata import *

# Pulse types
class Pulse:
    INVALID, START, ZERO, ONE = range(4)

# Protocol stats
class Stat:
    WAIT_START, GET_BITS, WAIT_EOM, WAIT_ACK = range(4)

# Pulse times in milliseconds
timing = {
    Pulse.START: {
        'low': { 'min': 3.5, 'max': 3.9 },
        'total': { 'min': 4.3, 'max': 4.7 }
    },
    Pulse.ZERO: {
        'low': { 'min': 1.3, 'max': 1.7 },
        'total': { 'min': 2.05, 'max': 2.75 }
    },
    Pulse.ONE: {
        'low': { 'min': 0.4, 'max': 0.8 },
        'total': { 'min': 2.05, 'max': 2.75 }
    }
}

class ChannelError(Exception):
    pass

class Decoder(srd.Decoder):
    api_version = 3
    id = 'cec'
    name = 'CEC'
    longname = 'HDMI-CEC'
    desc = 'HDMI Consumer Electronics Control (CEC) protocol.'
    license = 'gplv2+'
    inputs = ['logic']
    outputs = ['cec']
    channels = (
        {'id': 'cec', 'name': 'CEC', 'desc': 'CEC bus data'},
    )
    annotations = (
        ('st', 'Start'),
        ('eom-0', 'End of message'),
        ('eom-1', 'Message continued'),
        ('nack', 'ACK not set'),
        ('ack', 'ACK set'),
        ('bits', 'Bits'),
        ('bytes', 'Bytes'),
        ('frames', 'Frames'),
        ('sections', 'Sections'),
        ('warnings', 'Warnings')
    )
    annotation_rows = (
        ('bits', 'Bits', (0, 1, 2, 3, 4, 5)),
        ('bytes', 'Bytes', (6,)),
        ('frames', 'Frames', (7,)),
        ('sections', 'Sections', (8,)),
        ('warnings', 'Warnings', (9,))
    )

    def __init__(self):
        self.reset()

    def precalculate(self):
        # Restrict max length of ACK/NACK labels to 2 BIT pulses.
        bit_time = timing[Pulse.ZERO]['total']['min'] * 2
        self.max_ack_len_samples = round((bit_time / 1000) * self.samplerate)

    def reset(self):
        self.stat = Stat.WAIT_START
        self.samplerate = None
        self.fall_start = None
        self.fall_end = None
        self.rise = None
        self.reset_frame_vars()

    def reset_frame_vars(self):
        self.eom = None
        self.bit_count = 0
        self.byte_count = 0
        self.byte = 0
        self.byte_start = None
        self.frame_start = None
        self.frame_end = None
        self.is_nack = 0
        self.cmd_bytes = []

    def metadata(self, key, value):
        if key == srd.SRD_CONF_SAMPLERATE:
            self.samplerate = value
            self.precalculate()

    def handle_frame(self, is_nack):
        if self.fall_start is None or self.fall_end is None:
            return

        i = 0
        str = ''
        while i < len(self.cmd_bytes):
            str += '{:02x}'.format(self.cmd_bytes[i]['val'])
            if i != (len(self.cmd_bytes) - 1):
                str += ':'
            i += 1

        self.put(self.frame_start, self.frame_end, self.out_ann, [7, [str]])

        i = 0
        operands = 0
        str = ''
        while i < len(self.cmd_bytes):
            if i == 0: # Parse header
                (src, dst) = decode_header(self.cmd_bytes[i]['val'])
                str = 'HDR: ' + src + ', ' + dst
            elif i == 1: # Parse opcode
                str += ' | OPC: ' + opcodes.get(self.cmd_bytes[i]['val'], 'Invalid')
            else: # Parse operands
                if operands == 0:
                    str += ' | OPS: '
                operands += 1
                str += '0x{:02x}'.format(self.cmd_bytes[i]['val'])
                if i != len(self.cmd_bytes) - 1:
                    str += ', '
            i += 1

        # Header only commands are PINGS
        if i == 1:
            str += ' | OPC: PING' if self.eom else ' | OPC: NONE. Aborted cmd'

        # Add extra information (ack of the command from the destination)
        str += ' | R: NACK' if is_nack else ' | R: ACK'

        self.put(self.frame_start, self.frame_end, self.out_ann, [8, [str]])

    def process(self):
        zero_time = ((self.rise - self.fall_start) / self.samplerate) * 1000.0
        total_time = ((self.fall_end - self.fall_start) / self.samplerate) * 1000.0
        pulse = Pulse.INVALID

        # VALIDATION: Identify pulse based on length of the low period
        for key in timing:
            if zero_time >= timing[key]['low']['min'] and zero_time <= timing[key]['low']['max']:
                pulse = key
                break

        # VALIDATION: Invalid pulse
        if pulse == Pulse.INVALID:
            self.stat = Stat.WAIT_START
            self.put(self.fall_start, self.fall_end, self.out_ann, [9, ['Invalid pulse: Wrong timing']])
            return

        # VALIDATION: If waiting for start, discard everything else
        if self.stat == Stat.WAIT_START and pulse != Pulse.START:
            self.put(self.fall_start, self.fall_end, self.out_ann, [9, ['Expected START: BIT found']])
            return

        # VALIDATION: If waiting for ACK or EOM, only BIT pulses (0/1) are expected
        if (self.stat == Stat.WAIT_ACK or self.stat == Stat.WAIT_EOM) and pulse == Pulse.START:
            self.put(self.fall_start, self.fall_end, self.out_ann, [9, ['Expected BIT: START received)']])
            self.stat = Stat.WAIT_START

        # VALIDATION: ACK bit pulse remains high till the next frame (if any): Validate only min time of the low period
        if self.stat == Stat.WAIT_ACK and pulse != Pulse.START:
            if total_time < timing[pulse]['total']['min']:
                pulse = Pulse.INVALID
                self.put(self.fall_start, self.fall_end, self.out_ann, [9, ['ACK pulse below minimun time']])
                self.stat = Stat.WAIT_START
                return

        # VALIDATION / PING FRAME DETECTION: Initiator doesn't sets the EOM = 1 but stops sending when ack doesn't arrive
        if self.stat == Stat.GET_BITS and pulse == Pulse.START:
            # Make sure we received a complete byte to consider it a valid ping
            if self.bit_count == 0:
                self.handle_frame(self.is_nack)
            else:
                self.put(self.frame_start, self.samplenum, self.out_ann, [9, ['ERROR: Incomplete byte received']])

            # Set wait start so we receive next frame
            self.stat = Stat.WAIT_START

        # VALIDATION: Check timing of the BIT (0/1) pulse in any other case (not waiting for ACK)
        if self.stat != Stat.WAIT_ACK and pulse != Pulse.START:
            if total_time < timing[pulse]['total']['min'] or total_time > timing[pulse]['total']['max']:
                self.put(self.fall_start, self.fall_end, self.out_ann, [9, ['Bit pulse exceeds total pulse timespan']])
                pulse = Pulse.INVALID
                self.stat = Stat.WAIT_START
                return

        if pulse == Pulse.ZERO:
            bit = 0
        elif pulse == Pulse.ONE:
            bit = 1

        # STATE: WAIT START
        if self.stat == Stat.WAIT_START:
            self.stat = Stat.GET_BITS
            self.reset_frame_vars()
            self.put(self.fall_start, self.fall_end, self.out_ann, [0, ['ST']])

        # STATE: GET BITS
        elif self.stat == Stat.GET_BITS:
            # Reset stats on first bit
            if self.bit_count == 0:
                self.byte_start = self.fall_start
                self.byte = 0

                # If 1st byte of the datagram save its sample num
                if len(self.cmd_bytes) == 0:
                    self.frame_start = self.fall_start

            self.byte += (bit << (7 - self.bit_count))
            self.bit_count += 1
            self.put(self.fall_start, self.fall_end, self.out_ann, [5, [str(bit)]])

            if self.bit_count == 8:
                self.bit_count = 0
                self.byte_count += 1
                self.stat = Stat.WAIT_EOM
                self.put(self.byte_start, self.samplenum, self.out_ann, [6, ['0x{:02x}'.format(self.byte)]])
                self.cmd_bytes.append({'st': self.byte_start, 'ed': self.samplenum, 'val': self.byte})

        # STATE: WAIT EOM
        elif self.stat == Stat.WAIT_EOM:
            self.eom = bit
            self.frame_end = self.fall_end

            a = [2, ['EOM=Y']] if self.eom else [1, ['EOM=N']]
            self.put(self.fall_start, self.fall_end, self.out_ann, a)

            self.stat = Stat.WAIT_ACK

        # STATE: WAIT ACK
        elif self.stat == Stat.WAIT_ACK:
            # If a frame with broadcast destination is being sent, the ACK is
            # inverted: a 0 is considered a NACK, therefore we invert the value
            # of the bit here, so we match the real meaning of it.
            if (self.cmd_bytes[0]['val'] & 0x0F) == 0x0F:
                bit = ~bit & 0x01

            if (self.fall_end - self.fall_start) > self.max_ack_len_samples:
                ann_end = self.fall_start + self.max_ack_len_samples
            else:
                ann_end = self.fall_end

            if bit:
                # Any NACK detected in the frame is enough to consider the
                # whole frame NACK'd.
                self.is_nack = 1
                self.put(self.fall_start, ann_end, self.out_ann, [3, ['NACK']])
            else:
                self.put(self.fall_start, ann_end, self.out_ann, [4, ['ACK']])

            # After ACK bit, wait for new datagram or continue reading current
            # one based on EOM value.
            if self.eom or self.is_nack:
                self.stat = Stat.WAIT_START
                self.handle_frame(self.is_nack)
            else:
                self.stat = Stat.GET_BITS

    def start(self):
        self.out_ann = self.register(srd.OUTPUT_ANN)

    def decode(self):
        if not self.samplerate:
            raise SamplerateError('Cannot decode without samplerate.')

        # Wait for first falling edge.
        self.wait({0: 'f'})
        self.fall_end = self.samplenum

        while True:
            self.wait({0: 'r'})
            self.rise = self.samplenum

            if self.stat == Stat.WAIT_ACK:
                self.wait([{0: 'f'}, {'skip': self.max_ack_len_samples}])
            else:
                self.wait([{0: 'f'}])

            self.fall_start = self.fall_end
            self.fall_end = self.samplenum
            self.process()

            # If there was a timeout while waiting for ACK: RESYNC.
            # Note: This is an expected situation as no new falling edge will
            # happen until next frame is transmitted.
            if self.matched == (False, True):
                self.wait({0: 'f'})
                self.fall_end = self.samplenum
Commit	Line	Data
fb248c04 JS	1	##
	2	## This file is part of the libsigrokdecode project.
	3	##
	4	## Copyright (C) 2018 Jorge Solla Rubiales <jorgesolla@gmail.com>
	5	##
	6	## This program is free software; you can redistribute it and/or modify
	7	## it under the terms of the GNU General Public License as published by
	8	## the Free Software Foundation; either version 2 of the License, or
	9	## (at your option) any later version.
	10	##
	11	## This program is distributed in the hope that it will be useful,
	12	## but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	## GNU General Public License for more details.
	15	##
	16	## You should have received a copy of the GNU General Public License
	17	## along with this program. If not, see <http://www.gnu.org/licenses/>.
	18	##
	19
	20	import sigrokdecode as srd
	21	from .protocoldata import *
	22
	23	# Pulse types
	24	class Pulse:
	25	INVALID, START, ZERO, ONE = range(4)
	26
	27	# Protocol stats
	28	class Stat:
	29	WAIT_START, GET_BITS, WAIT_EOM, WAIT_ACK = range(4)
	30
	31	# Pulse times in milliseconds
	32	timing = {
	33	Pulse.START: {
	34	'low': { 'min': 3.5, 'max': 3.9 },
	35	'total': { 'min': 4.3, 'max': 4.7 }
	36	},
	37	Pulse.ZERO: {
	38	'low': { 'min': 1.3, 'max': 1.7 },
	39	'total': { 'min': 2.05, 'max': 2.75 }
	40	},
	41	Pulse.ONE: {
	42	'low': { 'min': 0.4, 'max': 0.8 },
	43	'total': { 'min': 2.05, 'max': 2.75 }
	44	}
	45	}
	46
	47	class ChannelError(Exception):
	48	pass
	49
	50	class Decoder(srd.Decoder):
	51	api_version = 3
	52	id = 'cec'
	53	name = 'CEC'
	54	longname = 'HDMI-CEC'
	55	desc = 'HDMI Consumer Electronics Control (CEC) protocol.'
	56	license = 'gplv2+'
	57	inputs = ['logic']
	58	outputs = ['cec']
	59	channels = (
	60	{'id': 'cec', 'name': 'CEC', 'desc': 'CEC bus data'},
	61	)
	62	annotations = (
	63	('st', 'Start'),
	64	('eom-0', 'End of message'),
65	('eom-1', 'Message continued'),
66	('nack', 'ACK not set'),
67	('ack', 'ACK set'),
68	('bits', 'Bits'),
69	('bytes', 'Bytes'),
70	('frames', 'Frames'),
71	('sections', 'Sections'),
72	('warnings', 'Warnings')
73	)
74	annotation_rows = (
75	('bits', 'Bits', (0, 1, 2, 3, 4, 5)),
76	('bytes', 'Bytes', (6,)),
77	('frames', 'Frames', (7,)),
78	('sections', 'Sections', (8,)),
79	('warnings', 'Warnings', (9,))
80	)
81
82	def __init__(self):
83	self.reset()
84
85	def precalculate(self):
86	# Restrict max length of ACK/NACK labels to 2 BIT pulses.
8a8b516a	87	bit_time = timing[Pulse.ZERO]['total']['min'] * 2
fb248c04 JS	88	self.max_ack_len_samples = round((bit_time / 1000) * self.samplerate)
	89
	90	def reset(self):
	91	self.stat = Stat.WAIT_START
	92	self.samplerate = None
	93	self.fall_start = None
	94	self.fall_end = None
	95	self.rise = None
	96	self.reset_frame_vars()
	97
	98	def reset_frame_vars(self):
	99	self.eom = None
	100	self.bit_count = 0
	101	self.byte_count = 0
	102	self.byte = 0
	103	self.byte_start = None
	104	self.frame_start = None
	105	self.frame_end = None
	106	self.is_nack = 0
	107	self.cmd_bytes = []
	108
	109	def metadata(self, key, value):
	110	if key == srd.SRD_CONF_SAMPLERATE:
	111	self.samplerate = value
	112	self.precalculate()
	113
fb248c04 JS	114	def handle_frame(self, is_nack):
	115	if self.fall_start is None or self.fall_end is None:
	116	return
	117
	118	i = 0
	119	str = ''
	120	while i < len(self.cmd_bytes):
	121	str += '{:02x}'.format(self.cmd_bytes[i]['val'])
	122	if i != (len(self.cmd_bytes) - 1):
	123	str += ':'
	124	i += 1
	125
	126	self.put(self.frame_start, self.frame_end, self.out_ann, [7, [str]])
	127
	128	i = 0
	129	operands = 0
	130	str = ''
	131	while i < len(self.cmd_bytes):
	132	if i == 0: # Parse header
	133	(src, dst) = decode_header(self.cmd_bytes[i]['val'])
	134	str = 'HDR: ' + src + ', ' + dst
	135	elif i == 1: # Parse opcode
89e636c4	136	str += ' \| OPC: ' + opcodes.get(self.cmd_bytes[i]['val'], 'Invalid')
fb248c04 JS	137	else: # Parse operands
	138	if operands == 0:
	139	str += ' \| OPS: '
	140	operands += 1
	141	str += '0x{:02x}'.format(self.cmd_bytes[i]['val'])
	142	if i != len(self.cmd_bytes) - 1:
	143	str += ', '
	144	i += 1
	145
	146	# Header only commands are PINGS
	147	if i == 1:
8a8b516a	148	str += ' \| OPC: PING' if self.eom else ' \| OPC: NONE. Aborted cmd'
fb248c04 JS	149
fb248c04 JS	150	# Add extra information (ack of the command from the destination)
8a8b516a	151	str += ' \| R: NACK' if is_nack else ' \| R: ACK'
fb248c04 JS	152
	153	self.put(self.frame_start, self.frame_end, self.out_ann, [8, [str]])
	154
	155	def process(self):
	156	zero_time = ((self.rise - self.fall_start) / self.samplerate) * 1000.0
	157	total_time = ((self.fall_end - self.fall_start) / self.samplerate) * 1000.0
	158	pulse = Pulse.INVALID
	159
	160	# VALIDATION: Identify pulse based on length of the low period
	161	for key in timing:
	162	if zero_time >= timing[key]['low']['min'] and zero_time <= timing[key]['low']['max']:
	163	pulse = key
	164	break
	165
	166	# VALIDATION: Invalid pulse
	167	if pulse == Pulse.INVALID:
e8c1209d	168	self.stat = Stat.WAIT_START
fb248c04 JS	169	self.put(self.fall_start, self.fall_end, self.out_ann, [9, ['Invalid pulse: Wrong timing']])
	170	return
	171
	172	# VALIDATION: If waiting for start, discard everything else
	173	if self.stat == Stat.WAIT_START and pulse != Pulse.START:
	174	self.put(self.fall_start, self.fall_end, self.out_ann, [9, ['Expected START: BIT found']])
	175	return
	176
	177	# VALIDATION: If waiting for ACK or EOM, only BIT pulses (0/1) are expected
	178	if (self.stat == Stat.WAIT_ACK or self.stat == Stat.WAIT_EOM) and pulse == Pulse.START:
	179	self.put(self.fall_start, self.fall_end, self.out_ann, [9, ['Expected BIT: START received)']])
e8c1209d	180	self.stat = Stat.WAIT_START
fb248c04 JS	181
	182	# VALIDATION: ACK bit pulse remains high till the next frame (if any): Validate only min time of the low period
	183	if self.stat == Stat.WAIT_ACK and pulse != Pulse.START:
	184	if total_time < timing[pulse]['total']['min']:
	185	pulse = Pulse.INVALID
	186	self.put(self.fall_start, self.fall_end, self.out_ann, [9, ['ACK pulse below minimun time']])
e8c1209d	187	self.stat = Stat.WAIT_START
fb248c04 JS	188	return
	189
	190	# VALIDATION / PING FRAME DETECTION: Initiator doesn't sets the EOM = 1 but stops sending when ack doesn't arrive
	191	if self.stat == Stat.GET_BITS and pulse == Pulse.START:
	192	# Make sure we received a complete byte to consider it a valid ping
	193	if self.bit_count == 0:
	194	self.handle_frame(self.is_nack)
	195	else:
	196	self.put(self.frame_start, self.samplenum, self.out_ann, [9, ['ERROR: Incomplete byte received']])
	197
	198	# Set wait start so we receive next frame
e8c1209d	199	self.stat = Stat.WAIT_START
fb248c04 JS	200
	201	# VALIDATION: Check timing of the BIT (0/1) pulse in any other case (not waiting for ACK)
	202	if self.stat != Stat.WAIT_ACK and pulse != Pulse.START:
	203	if total_time < timing[pulse]['total']['min'] or total_time > timing[pulse]['total']['max']:
	204	self.put(self.fall_start, self.fall_end, self.out_ann, [9, ['Bit pulse exceeds total pulse timespan']])
	205	pulse = Pulse.INVALID
e8c1209d	206	self.stat = Stat.WAIT_START
fb248c04 JS	207	return
	208
	209	if pulse == Pulse.ZERO:
	210	bit = 0
	211	elif pulse == Pulse.ONE:
	212	bit = 1
	213
	214	# STATE: WAIT START
	215	if self.stat == Stat.WAIT_START:
e8c1209d	216	self.stat = Stat.GET_BITS
fb248c04 JS	217	self.reset_frame_vars()
	218	self.put(self.fall_start, self.fall_end, self.out_ann, [0, ['ST']])
	219
	220	# STATE: GET BITS
	221	elif self.stat == Stat.GET_BITS:
	222	# Reset stats on first bit
	223	if self.bit_count == 0:
	224	self.byte_start = self.fall_start
	225	self.byte = 0
	226
	227	# If 1st byte of the datagram save its sample num
	228	if len(self.cmd_bytes) == 0:
	229	self.frame_start = self.fall_start
	230
	231	self.byte += (bit << (7 - self.bit_count))
	232	self.bit_count += 1
	233	self.put(self.fall_start, self.fall_end, self.out_ann, [5, [str(bit)]])
	234
	235	if self.bit_count == 8:
	236	self.bit_count = 0
	237	self.byte_count += 1
e8c1209d	238	self.stat = Stat.WAIT_EOM
fb248c04 JS	239	self.put(self.byte_start, self.samplenum, self.out_ann, [6, ['0x{:02x}'.format(self.byte)]])
	240	self.cmd_bytes.append({'st': self.byte_start, 'ed': self.samplenum, 'val': self.byte})
	241
	242	# STATE: WAIT EOM
	243	elif self.stat == Stat.WAIT_EOM:
	244	self.eom = bit
	245	self.frame_end = self.fall_end
	246
8a8b516a UH	247	a = [2, ['EOM=Y']] if self.eom else [1, ['EOM=N']]
8a8b516a UH	248	self.put(self.fall_start, self.fall_end, self.out_ann, a)
fb248c04	249
e8c1209d	250	self.stat = Stat.WAIT_ACK
fb248c04 JS	251
	252	# STATE: WAIT ACK
	253	elif self.stat == Stat.WAIT_ACK:
	254	# If a frame with broadcast destination is being sent, the ACK is
	255	# inverted: a 0 is considered a NACK, therefore we invert the value
	256	# of the bit here, so we match the real meaning of it.
	257	if (self.cmd_bytes[0]['val'] & 0x0F) == 0x0F:
	258	bit = ~bit & 0x01
	259
	260	if (self.fall_end - self.fall_start) > self.max_ack_len_samples:
	261	ann_end = self.fall_start + self.max_ack_len_samples
	262	else:
	263	ann_end = self.fall_end
	264
	265	if bit:
	266	# Any NACK detected in the frame is enough to consider the
	267	# whole frame NACK'd.
	268	self.is_nack = 1
	269	self.put(self.fall_start, ann_end, self.out_ann, [3, ['NACK']])
	270	else:
	271	self.put(self.fall_start, ann_end, self.out_ann, [4, ['ACK']])
	272
	273	# After ACK bit, wait for new datagram or continue reading current
	274	# one based on EOM value.
	275	if self.eom or self.is_nack:
e8c1209d	276	self.stat = Stat.WAIT_START
fb248c04 JS	277	self.handle_frame(self.is_nack)
fb248c04 JS	278	else:
e8c1209d	279	self.stat = Stat.GET_BITS
fb248c04 JS	280
	281	def start(self):
	282	self.out_ann = self.register(srd.OUTPUT_ANN)
	283
	284	def decode(self):
	285	if not self.samplerate:
	286	raise SamplerateError('Cannot decode without samplerate.')
	287
	288	# Wait for first falling edge.
	289	self.wait({0: 'f'})
	290	self.fall_end = self.samplenum
	291
	292	while True:
	293	self.wait({0: 'r'})
	294	self.rise = self.samplenum
	295
	296	if self.stat == Stat.WAIT_ACK:
	297	self.wait([{0: 'f'}, {'skip': self.max_ack_len_samples}])
	298	else:
	299	self.wait([{0: 'f'}])
	300
	301	self.fall_start = self.fall_end
	302	self.fall_end = self.samplenum
	303	self.process()
	304
	305	# If there was a timeout while waiting for ACK: RESYNC.
	306	# Note: This is an expected situation as no new falling edge will
	307	# happen until next frame is transmitted.
	308	if self.matched == (False, True):
	309	self.wait({0: 'f'})
	310	self.fall_end = self.samplenum