In callback function of isochronous context, u32 variable is passed for cycle count. The value of this variable comes from DMA descriptors of 1394 Open Host Controller Interface (1394 OHCI). In the specification, DMA descriptors transport lower 3 bits for second field and full cycle field in 16 bits field, therefore 16 bits of the u32 variable are available. The value for second is modulo 8, and the value for cycle is modulo 8,000.

Currently, ALSA firewire-lib module don't use the value of the second field, because the value is useless to calculate presentation timestamp in IEC 61883-6. However, the value may be useful for debugging. In later commit, it will be printed with the other parameters for debugging.

This commit makes this module to handle the whole cycle count including second. The value is calculated by cycle unit. The existed code is already written with ignoring the value of second, thus this commit causes no issues.

Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp --- sound/firewire/amdtp-stream.c | 42 ++++++++++++++++++++++++++++++------------ 1 file changed, 30 insertions(+), 12 deletions(-)

diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c index 4484242..46f1167 100644 --- a/sound/firewire/amdtp-stream.c +++ b/sound/firewire/amdtp-stream.c @@ -548,26 +548,44 @@ end: return 0; }

-static void out_stream_callback(struct fw_iso_context *context, u32 cycle, +/* + * In CYCLE_TIMER register of IEEE 1394, 7 bits are used to represent second. On + * the other hand, in DMA descriptors of 1394 OHCI, 3 bits are used to represent + * it. Thus, via Linux firewire subsystem, we can get the 3 bits for second. + */ +static inline u32 compute_cycle_count(u32 tstamp) +{ + return (((tstamp >> 13) & 0x07) * 8000) + (tstamp & 0x1fff); +} + +static inline u32 increment_cycle_count(u32 cycle, unsigned int addend) +{ + cycle += addend; + if (cycle >= 8 * CYCLES_PER_SECOND) + cycle -= 8 * CYCLES_PER_SECOND; + return cycle; +} + +static void out_stream_callback(struct fw_iso_context *context, u32 tstamp, size_t header_length, void *header, void *private_data) { struct amdtp_stream *s = private_data; unsigned int i, syt, packets = header_length / 4; unsigned int data_blocks; + u32 cycle;

if (s->packet_index < 0) return;

- /* - * Compute the cycle of the last queued packet. - * (We need only the four lowest bits for the SYT, so we can ignore - * that bits 0-11 must wrap around at 3072.) - */ - cycle += QUEUE_LENGTH - packets; + cycle = compute_cycle_count(tstamp); + + /* Align to actual cycle count for the last packet. */ + cycle = increment_cycle_count(cycle, QUEUE_LENGTH - packets);

for (i = 0; i < packets; ++i) { - syt = calculate_syt(s, ++cycle); + cycle = increment_cycle_count(cycle, 1); + syt = calculate_syt(s, cycle); data_blocks = calculate_data_blocks(s, syt);

if (handle_out_packet(s, data_blocks, syt) < 0) { @@ -580,7 +598,7 @@ static void out_stream_callback(struct fw_iso_context *context, u32 cycle, fw_iso_context_queue_flush(s->context); }

-static void in_stream_callback(struct fw_iso_context *context, u32 cycle, +static void in_stream_callback(struct fw_iso_context *context, u32 tstamp, size_t header_length, void *header, void *private_data) { @@ -650,7 +668,7 @@ static void in_stream_callback(struct fw_iso_context *context, u32 cycle, }

/* processing is done by master callback */ -static void slave_stream_callback(struct fw_iso_context *context, u32 cycle, +static void slave_stream_callback(struct fw_iso_context *context, u32 tstamp, size_t header_length, void *header, void *private_data) { @@ -659,7 +677,7 @@ static void slave_stream_callback(struct fw_iso_context *context, u32 cycle,

/* this is executed one time */ static void amdtp_stream_first_callback(struct fw_iso_context *context, - u32 cycle, size_t header_length, + u32 tstamp, size_t header_length, void *header, void *private_data) { struct amdtp_stream *s = private_data; @@ -678,7 +696,7 @@ static void amdtp_stream_first_callback(struct fw_iso_context *context, else context->callback.sc = out_stream_callback;

- context->callback.sc(context, cycle, header_length, header, s); + context->callback.sc(context, tstamp, header_length, header, s); }

/**

When audio and music units have some quirks in their sequence of packet, it's really hard for non-owners to identify the quirks. Although developers need dumps for sequence of packets, it's difficult for users who have no knowledges and no equipments for this purpose.

This commit adds tracepoints for this situation. When users encounter the issue, they can dump a part of packet data via Linux tracing framework as long as using drivers in ALSA firewire stack.

Additionally, tracepoints for outgoing packets will be our help to check and debug packet processing of ALSA firewire stack.

This commit newly adds 'snd_firewire_lib' subsystem with 'in_packet' and 'out_packet' events. In the events, some attributes of packets and the index of packet managed by this module are recorded per packet.

This is an usage:

$ trace-cmd record -e snd_firewire_lib:out_packet \ -e snd_firewire_lib:in_packet /sys/kernel/tracing/events/snd_firewire_lib/out_packet/filter /sys/kernel/tracing/events/snd_firewire_lib/in_packet/filter Hit Ctrl^C to stop recording ^C $ trace-cmd report trace.dat ... 23647.033934: in_packet: 01 4073 ffc0 ffc1 00 000f0040 9001b2d1 122 44 23647.033936: in_packet: 01 4074 ffc0 ffc1 00 000f0048 9001c83b 122 45 23647.033937: in_packet: 01 4075 ffc0 ffc1 00 000f0050 9001ffff 002 46 23647.033938: in_packet: 01 4076 ffc0 ffc1 00 000f0050 9001e1a6 122 47 23647.035426: out_packet: 01 4123 ffc1 ffc0 01 010f00d0 9001fb40 122 17 23647.035428: out_packet: 01 4124 ffc1 ffc0 01 010f00d8 9001ffff 002 18 23647.035429: out_packet: 01 4125 ffc1 ffc0 01 010f00d8 900114aa 122 19 23647.035430: out_packet: 01 4126 ffc1 ffc0 01 010f00e0 90012a15 122 20 (Here, some common fields are omitted so that a line to be within 80 characters.) ...

One line represent one packet. The legend for the last nine fields is: - The second of cycle scheduled for the packet - The count of cycle scheduled for the packet - The ID of node as source (hex) - Some devices transfer packets with invalid source node ID in their CIP header. - The ID of node as destination (hex) - The value is not in CIP header of packets. - The value of isochronous channel - The first quadlet of CIP header (hex) - The second quadlet of CIP header (hex) - The number of included quadlets - The index of packet in a buffer maintained by this module

This is an example to parse these lines from text file by Python3 script:

#!/usr/bin/env python3 import sys

def parse_ts(second, cycle, syt): offset = syt & 0xfff syt >>= 12 if cycle & 0x0f > syt: cycle += 0x10 cycle &= 0x1ff0 cycle |= syt second += cycle // 8000 cycle %= 8000 # In CYCLE_TIMER of 1394 OHCI, second is represented in 8 bit. second %= 128 return (second, cycle, offset)

def calc_ts(second, cycle, offset): ts = offset ts += cycle * 3072 # In DMA descriptor of 1394 OHCI, second is represented in 3 bit. ts += (second % 8) * 8000 * 3072 return ts

def subtract_ts(minuend, subtrahend): # In DMA descriptor of 1394 OHCI, second is represented in 3 bit. if minuend < subtrahend: minuend += 8 * 8000 * 3072 return minuend - subtrahend

if len(sys.argv) != 2: print('At least, one argument is required for packet dump.') sys.exit()

filename = sys.argv[1]

data = []

prev = 0 with open(filename, 'r') as f: for line in f: pos = line.find('packet:') if pos < 0: continue

pos += len('packet:') line = line[pos:].strip() fields = line.split(' ')

datum = []

datum.append(fields[8])

syt = int(fields[6][4:], 16)

# Empty packet in IEC 61883-1, or NODATA in IEC 61883-6 if syt == 0xffff: data_blocks = 0 else: payload_size = int(fields[7], 10) data_block_size = int(fields[5][2:4], 16) data_blocks = (payload_size - 2) / data_block_size datum.append(data_blocks)

second = int(fields[0], 10) cycle = int(fields[1], 10) start = (second << 25) | (cycle << 12) datum.append('0x{0:08x}'.format(start)) start = calc_ts(second, cycle, 0)

datum.append("0x" + fields[5]) datum.append("0x" + fields[6])

if syt == 0xffff: second = 0 cycle = 0 tick = 0 else: second, cycle, tick = parse_ts(second, cycle, syt) ts = calc_ts(second, cycle, tick) datum.append(start) datum.append(ts) if ts == 0: datum.append(0) datum.append(0) else: # Usual case, or a case over 8 seconds. if ts > start or start > 7 * 8000 * 3072: datum.append(subtract_ts(ts, start)) if ts > prev or start > 7 * 8000 * 3072: gap = subtract_ts(ts, prev) datum.append(gap) else: datum.append('backward') else: datum.append('invalid') prev = ts

data.append(datum)

sys.exit()

The data variable includes array with these elements: - The index of the packet - The number of data blocks in the packet - The value of cycle count (hex) - The value of CIP header 1 (hex) - The value of CIP header 2 (hex) - The value of cycle count (tick) - The value of calculated presentation timestamp (tick) - The offset between the cycle count and presentation timestamp - The elapsed ticks from the previous presentation timestamp

Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp --- sound/firewire/Makefile | 3 ++ sound/firewire/amdtp-stream-trace.h | 98 +++++++++++++++++++++++++++++++++++++ sound/firewire/amdtp-stream.c | 21 +++++--- 3 files changed, 116 insertions(+), 6 deletions(-) create mode 100644 sound/firewire/amdtp-stream-trace.h

diff --git a/sound/firewire/Makefile b/sound/firewire/Makefile index 003c090..0ee1fb1 100644 --- a/sound/firewire/Makefile +++ b/sound/firewire/Makefile @@ -1,3 +1,6 @@ +# To find a header included by define_trace.h. +CFLAGS_amdtp-stream.o := -I$(src) + snd-firewire-lib-objs := lib.o iso-resources.o packets-buffer.o \ fcp.o cmp.o amdtp-stream.o amdtp-am824.o snd-isight-objs := isight.o diff --git a/sound/firewire/amdtp-stream-trace.h b/sound/firewire/amdtp-stream-trace.h new file mode 100644 index 0000000..425d1d7 --- /dev/null +++ b/sound/firewire/amdtp-stream-trace.h @@ -0,0 +1,98 @@ +/* + * amdtp-stream-trace.h - tracepoint definitions to dump a part of packet data + * + * Copyright (c) 2016 Takashi Sakamoto + * Licensed under the terms of the GNU General Public License, version 2. + */ + +#undef TRACE_SYSTEM +#define TRACE_SYSTEM snd_firewire_lib + +#if !defined(_AMDTP_STREAM_TRACE_H) || defined(TRACE_HEADER_MULTI_READ) +#define _AMDTP_STREAM_TRACE_H + +#include <linux/tracepoint.h> + +TRACE_EVENT(in_packet, + TP_PROTO(const struct amdtp_stream *s, u32 cycles, u32 cip_header[2], unsigned int payload_quadlets), + TP_ARGS(s, cycles, cip_header, payload_quadlets), + TP_STRUCT__entry( + __field(unsigned int, second) + __field(unsigned int, cycle) + __field(int, channel) + __field(int, src) + __field(int, dest) + __field(u32, cip_header0) + __field(u32, cip_header1) + __field(unsigned int, payload_quadlets) + __field(unsigned int, index) + ), + TP_fast_assign( + __entry->second = cycles / CYCLES_PER_SECOND; + __entry->cycle = cycles % CYCLES_PER_SECOND; + __entry->channel = s->context->channel; + __entry->src = fw_parent_device(s->unit)->node_id; + __entry->dest = fw_parent_device(s->unit)->card->node_id; + __entry->cip_header0 = cip_header[0]; + __entry->cip_header1 = cip_header[1]; + __entry->payload_quadlets = payload_quadlets; + __entry->index = s->packet_index; + ), + TP_printk( + "%02u %04u %04x %04x %02d %08x %08x %03u %02u", + __entry->second, + __entry->cycle, + __entry->src, + __entry->dest, + __entry->channel, + __entry->cip_header0, + __entry->cip_header1, + __entry->payload_quadlets, + __entry->index) +); + +TRACE_EVENT(out_packet, + TP_PROTO(const struct amdtp_stream *s, u32 cycles, __be32 *cip_header, unsigned int payload_length), + TP_ARGS(s, cycles, cip_header, payload_length), + TP_STRUCT__entry( + __field(unsigned int, second) + __field(unsigned int, cycle) + __field(int, channel) + __field(int, src) + __field(int, dest) + __field(u32, cip_header0) + __field(u32, cip_header1) + __field(unsigned int, payload_quadlets) + __field(unsigned int, index) + ), + TP_fast_assign( + __entry->second = cycles / CYCLES_PER_SECOND; + __entry->cycle = cycles % CYCLES_PER_SECOND; + __entry->channel = s->context->channel; + __entry->src = fw_parent_device(s->unit)->card->node_id; + __entry->dest = fw_parent_device(s->unit)->node_id; + __entry->cip_header0 = be32_to_cpu(cip_header[0]); + __entry->cip_header1 = be32_to_cpu(cip_header[1]); + __entry->payload_quadlets = payload_length / 4; + __entry->index = s->packet_index; + ), + TP_printk( + "%02u %04u %04x %04x %02d %08x %08x %03u %02u", + __entry->second, + __entry->cycle, + __entry->src, + __entry->dest, + __entry->channel, + __entry->cip_header0, + __entry->cip_header1, + __entry->payload_quadlets, + __entry->index) +); + +#endif + +#undef TRACE_INCLUDE_PATH +#define TRACE_INCLUDE_PATH . +#undef TRACE_INCLUDE_FILE +#define TRACE_INCLUDE_FILE amdtp-stream-trace +#include <trace/define_trace.h> diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c index 4d86da0..a22e559 100644 --- a/sound/firewire/amdtp-stream.c +++ b/sound/firewire/amdtp-stream.c @@ -19,6 +19,10 @@ #define CYCLES_PER_SECOND 8000 #define TICKS_PER_SECOND (TICKS_PER_CYCLE * CYCLES_PER_SECOND)

+/* Always support Linux tracing subsystem. */ +#define CREATE_TRACE_POINTS +#include "amdtp-stream-trace.h" + #define TRANSFER_DELAY_TICKS 0x2e00 /* 479.17 microseconds */

/* isochronous header parameters */ @@ -409,7 +413,7 @@ static inline int queue_in_packet(struct amdtp_stream *s) }

static int handle_out_packet(struct amdtp_stream *s, unsigned int data_blocks, - unsigned int syt) + unsigned int cycle, unsigned int syt) { __be32 *buffer; unsigned int payload_length; @@ -428,8 +432,10 @@ static int handle_out_packet(struct amdtp_stream *s, unsigned int data_blocks, (syt & CIP_SYT_MASK));

s->data_block_counter = (s->data_block_counter + data_blocks) & 0xff; - payload_length = 8 + data_blocks * 4 * s->data_block_quadlets; + + trace_out_packet(s, cycle, buffer, payload_length); + if (queue_out_packet(s, payload_length, false) < 0) return -EIO;

@@ -443,7 +449,8 @@ static int handle_out_packet(struct amdtp_stream *s, unsigned int data_blocks,

static int handle_in_packet(struct amdtp_stream *s, unsigned int payload_quadlets, __be32 *buffer, - unsigned int *data_blocks, unsigned int syt) + unsigned int *data_blocks, unsigned int cycle, + unsigned int syt) { u32 cip_header[2]; unsigned int fmt, fdf; @@ -455,6 +462,8 @@ static int handle_in_packet(struct amdtp_stream *s, cip_header[0] = be32_to_cpu(buffer[0]); cip_header[1] = be32_to_cpu(buffer[1]);

+ trace_in_packet(s, cycle, cip_header, payload_quadlets); + /* * This module supports 'Two-quadlet CIP header with SYT field'. * For convenience, also check FMT field is AM824 or not. @@ -595,7 +604,7 @@ static void out_stream_callback(struct fw_iso_context *context, u32 tstamp, syt = calculate_syt(s, cycle); data_blocks = calculate_data_blocks(s, syt);

- if (handle_out_packet(s, data_blocks, syt) < 0) { + if (handle_out_packet(s, data_blocks, cycle, syt) < 0) { s->packet_index = -1; amdtp_stream_pcm_abort(s); return; @@ -647,7 +656,7 @@ static void in_stream_callback(struct fw_iso_context *context, u32 tstamp,

syt = be32_to_cpu(buffer[1]) & CIP_SYT_MASK; if (handle_in_packet(s, payload_quadlets, buffer, - &data_blocks, syt) < 0) { + &data_blocks, cycle, syt) < 0) { s->packet_index = -1; break; } @@ -655,7 +664,7 @@ static void in_stream_callback(struct fw_iso_context *context, u32 tstamp, /* Process sync slave stream */ if (s->sync_slave && s->sync_slave->callbacked) { if (handle_out_packet(s->sync_slave, - data_blocks, syt) < 0) { + data_blocks, cycle, syt) < 0) { s->packet_index = -1; break; }