ALSA: firewire-lib: handle quirk to calculate payload quadlets as data block counter

Miglia Harmony Audio (OXFW970) has a quirk to put the number of
accumulated quadlets in CIP payload into the dbc field of CIP header.

This commit handles the quirk in the packet processing layer.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20240218074128.95210-4-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: obsolete return value from context payload processing layer

This commit obsoletes return value from the context payload processing layer
since the multiplier between the data block count and PCM frame count was
moved to the packet streaming processing layer.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20230110134933.322794-3-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: move parameter for pcm frame multiplier from context payload processing layer

The current implementation delegates the task to calculate the number of
processed PCM frames into the context payload processing layer. It looks
good as long as frame calculation is done for a single purpose.
Nevertheless, another purpose, the computation of extra delay for the
runtime of PCM substream, requires frame calculation, too.

This commit refactors the current implementation so that the packet stream
processing layer is responsible for the calculation of PCM frame, too. The
member is moved to stream structure for multiplier between data block
count and PCM frame count.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20230110134933.322794-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: keep history to process isochronous packet

The history to process isochronous packets is useful when computing gap
between current isochronous cycle and the latest isochronous cycle in
which packet is processed (in IR context) and scheduled (in IT context).

This commit stores the most recent packet descriptors to keep the history.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20230109021738.75543-4-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: use circular linked list for context payload processing layer

The list of packet descriptor is passed to context payload processing
layer so that each driver can copy PCM frames, MIDI messages, and device
specific data between packet payload buffer and intermediate buffer for
user space application.

The list of packet descriptor was replaced by circular linked list in a
previous commit. This commit uses circular linked in context payload
processing layer as well.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20230109021738.75543-3-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: use circular linked list to enumerate packet descriptors

Current implementation uses list of packet descriptor as template to
schedule isochronous packet. The packet descriptors are operated by
position and size, while circular linked list is convenient to enumerate
the packet descriptors.

This commit utilizes circular linked list for the purpose.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20230109021738.75543-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: code refactoring for cache position in sequence replay

When sequence replay is enabled for media clock recovery, current
implementation refers to cache of sequence descriptors in tx packets, then
fulfil sequence descriptors for rx packets. The initialization for rx
packets is done before starting packet streaming, while it can be postponed
till the cache has enough entries for the replay.

This commit refactors for the purpose as well as minor code change for
renaming of structure member.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20230107023214.29132-5-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: code refactoring for cache position in tx packets

When sequence replay is enabled for media clock recovery, current
implementation caches sequence descriptors from packet descriptors in tx
packets. Helper function for the purpose do not necessarily have good
readability.

This commit refactors relevant functions by renaming structure members,
function name, and function local variables.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20230107023214.29132-4-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: code refactoring for pool position in rx packets

When scheduling transmission of rx packets, current implementation
fulfils packet descriptors after pooling sequence descriptors. It is for
packet queueing. Besides the implementations do not necessarily have
good readability.

This commit refactors them by adding function local variables and
function arguments.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20230107023214.29132-3-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: code refactoring for helper functions to pool sequence in rx packets

When scheduling transmission of rx packets, current implementation pools
sequence descriptors at first for media clock. Two methods are used for
the purpose depending on four cases, while the implementations do not
necessarily have good readability.

This commit refactors them by adding function pointers and functions
arguments.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20230107023214.29132-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: obsolete workqueue for period update

The workqueue to notify PCM period elapse is not used anymore.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210610031733.56297-4-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: transfer rx packets on-the-fly when replaying

Models in below series start transmission of packet after receiving the
sequence of packets:

* Digidesign Digi00x family
* RME Fireface series

Additionally, models in Tascam FireWire series start multiplexing PCM
frames into packets enough after receiving packets. It's required to
transfer packets on-the-fly for the above models according to nominal
sampling transfer frequency before starting sequence replay.

This commit allows drivers to decide whether the engine transfers packet
on-the-fly or not.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210527122611.173711-4-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: replay sequence of incoming packets for outgoing packets

ALSA IEC 61883-1/6 packet streaming engine uses pre-computed parameters
ideal for nominal sampling transfer frequency (STF) to transfer packets
to device since it was added 2011. As a result of user experience for a
decade, it is clear that the sequence is not suitable to some actual
devices. It takes the devices to generate noise, and causes any type of
discontinuity in the series of packet transferred from the device. It's
required for the engine to transfer packets according to effective STF.

The effective STF is given by media clock recovered by the sequence of
packet transferred from the target device. In the previous commit, the
sequence is already cached. The media clock recovery can be achieved by
analyzing the sequence.

In technological world, many ideas are proposed for media clock recovery.
However, the small part of them could be actually adopted in our case
since floating point arithmetic is not mostly available in Linux kernel
land.

This commit adopts the simple way from them; sequence replay, which means
that the sequence of parameters from incoming packet is used as is to
transfer outgoing packets. The media clock is not computed internally,
but the sequence of outgoing packet superficially looks to be generated by
the media clock.

The association between source and destination is decided when starting
AMDTP domain. When the target device supports a pair of isochronous packet
streams, the tx stream is source and the rx stream is destination. When it
supports two pair of streams, each of tx stream is associated to
corresponding rx stream in its order. When it supports less number of tx
streams than rx streams, the fist tx stream is selected for all of rx
streams. When it supports more tx streams than rx streams, the first tx
packet is associated to the rx stream.

As I noted in previous commit, the sequence of parameters from incoming
packet is different between devices, time to time. It is worse idea to
replay the sequence of parameters from a device for the sequence of
packet to the other devices even if they are in the same category of
device.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210527122611.173711-3-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: add replay target to cache sequence of packet

In design of audio and music unit in IEEE 1394 bus, feedback of
effective sampling transfer frequency (STF) is delivered by packets
transferred from device. The devices supported by ALSA firewire stack
are categorized to three groups regarding to it.

* Group 1:
* Echo Audio Fireworks board module
* Oxford Semiconductor OXFW971 ASIC
* Digidesign Digi00x family
* Tascam FireWire series
* RME Fireface series

* Group 2:
* BridgeCo. DM1000/DM1100/DM1500 ASICs for BeBoB solution
* TC Applied Technologies DICE ASICs

* Group 3:
* Mark of the Unicord FireWire series

In group 1, the effective STF is determined by the sequence of the number
of events per packet. In group 2, the sequence of presentation timestamp
expressed in syt field of CIP header is interpreted as well. In group 3,
the presentation timestamp is expressed in source packet header (SPH) of
each data block.

I note that some models doesn't take care of effective STF with large
internal buffer. It's reasonable to name it as group 0:

* Group 0
* Oxford Semiconductor OXFW970 ASIC

The effective STF is known to be slightly different from nominal STF for
all of devices, and to be different between the devices. Furthermore, the
effective STF is known to be shifted for long-period transmission. This
makes it hard for software to satisfy the effective STF when processing
packets to the device.

The effective STF is deterministic as a result of analyzing the batch of
packet transferred from the device. For the analysis, caching the sequence
of parameter in the packet is required.

This commit adds an option so that AMDTP domain structure takes AMDTP
stream structure to cache the sequence of parameters in packet transferred
from the device. The parameters are offset ticks of syt field against the
cycle to receive the packet and the number of data blocks per packet.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210527122611.173711-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: obsolete callbacked member

The member of callbacked in AMDTP stream structure is not used anymore.
Instead, ready_processing member is used to wake up yielding task of user
process.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210524031346.50539-3-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: drop initial NODATA or empty packet

The devices based on BeBoB ASICs or the devices in Tascam FireWire
series transfer a batch of NODATA packet or empty packet in the beginning
of packet streaming. To avoid processing them, current implementation uses
an option to skip processing content of tx packet during some initial
cycles. However, the hard-coded number is not enough useful.

This commit drops content of packets till the packet includes any event
firstly. The function of option is to skip processing content of tx packet
with any event after dropping.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210524031346.50539-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: code refactoring for transfer delay

In later commit, transfer delay is used in both IR and IT contexts. This
commit refactors regardless of transfer delay.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210522013303.49596-7-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: pool sequence of packet in IT context independently

Current implementation pools the sequence in AMDTP domain. This is convenient
regarding to memory usage and computation time, however inconvenient for the
devices such that several rx streams are expected to transfer timing
information independently.

This commit refactors to pool the sequence per rx packet stream.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210522013303.49596-3-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: add flag to unaware of syt in CIP header

Many devices are unaware of syt field in rx CIP for playback timing.

This commit adds a flag to cancel processing syt field. Actually,
syt calculation is required to decide the number of events per rx packet.
The flag put 0xffff to CIP header of rx packet. On the other hand,
The value of syt field in CIP header of tx packet is unavailable. The
sequence of packet descriptor for tx packet includes 0 for the offset
of syt field to avoid computation.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210522013303.49596-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: change waking up timing to process packets

When starting AMDTP domain, tasks in process context yields running CPU
till all of isochronous context get callback, with an assumption that
it's OK to process content of packet.

However several isochronous cycles are skipped to transfer rx packets, or
the content of rx packets are dropped, to manage the timing to start
processing the packets.

This commit changes the timing for tasks in process context to wake up
when processing content of packet is actually ready.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210520040154.80450-9-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: start processing content of packet at the same cycle in several IT contexts

DICE ASICs support several pairs of isochronous packet streaming and
expect software to queue packets with the same timing information into
the same isochronous cycle.

This commit adds structure member to manage the cycle to start
processing packet in several IT contexts. The cycle is decided when
batch of isochronous cycle is skipped in callback to isochronous context
for IRQ target.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210520040154.80450-8-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: skip initial packets instead of scheduling IR context

Current implementation of ALSA IEC 61883-1/6 packet streaming engine
allows drivers to decide isochronous cycle to start IR context. This
option is mainly used to avoid processing the sequence of packet with
some quirks; e.g. discontinuity of counter. However, it's inconvenient
to fail to continue packet processing when the target device doesn't
start transmission of packet till the decided cycle.

This commit changes the behaviour. As an alternative to the start cycle
for IR context, the cycle count to drop content of packet in the beginning
of IR context.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210520040154.80450-6-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: start processing content of packet at the same cycle in several IR contexts

DICE ASICs support several pairs of isochronous packet streaming. It's
convenient for drivers to process content of the packet in the same cycle
timing.

This commit adds structure member to manage the cycle to start
processing packet in several IR contexts. The cycle is decided in the
first callback of the IR contexts. The content of packet is dropped
till the cycle.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210520040154.80450-5-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: check cycle continuity

Within devices supported by drivers in ALSA firewire stack, OXFW-based
devices and Fireface devices are known to skip isochronous cycle for
packet transmission. The former is due to the jumbo payload quirk. The
latter is due to vendor protocol in which empty packet is not
transferred in blocking mode.

Although nothing to do just for handling events of the packet, packet
continuity is necessarily for media clock recovery. This commit checks
whether any cycle is continue or not.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210518130048.146596-8-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: code refactoring for sequence descriptor'

A internal structure is used to gather parameters relevant to sequence
descriptor.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210518130048.146596-4-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: code refactoring to refer the same frame count per period in domain structure

The number of PCM frame per period is common between PCM substreams
handled in AMDTP stream in AMDTP domain.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210518130048.146596-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib/motu: use int type for the value of bitwise OR with enumerator-constant

It brings some inconvenience in practice to use enumerated type for
variable to which bitwise OR with enumerator constant is assigned.

This commit replaces declarations of enumerated type with int type.

Suggested-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210518084557.102681-3-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire: fix comparison to bool warning

Fix the following coccicheck warning:

./sound/firewire/amdtp-stream.h:273:6-19: WARNING: Comparison to bool

Reported-by: Tosk Robot <tencent_os_robot@tencent.com>
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Link: https://lore.kernel.org/r/1604765611-8209-1-git-send-email-kaixuxia@tencent.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire: Replace tasklet with work

The tasklet is an old API that should be deprecated, usually can be
converted to another decent API. In FireWire driver, a tasklet is
still used for offloading the AMDTP PCM stream handling. It can be
achieved gracefully with a work queued, too.

This patch replaces the tasklet usage in firewire-lib driver with a
simple work. The conversion is fairly straightforward but for the
in_interrupt() checks that are replaced with the check using the
current_work().

Note that in_interrupt() in amdtp_packet tracepoint is still kept as
is. This is the place that is probed by both softirq of 1394 OHCI and
a user task of a PCM application, and the work handling is already
filtered in amdtp_domain_stream_pcm_pointer().

Tested-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Acked-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20200909163659.21708-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: use sequence of syt offset and data block on pool in AMDTP domain

In previous commit, the sequence of syt offset and the number of data
blocks per packet is calculated for pool in AMDTP domain structure in
advance of processing outgoing packets.

This commit uses the sequence for outgoing packet processing to obsolete
per-stream processing of the sequence.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20200508043635.349339-11-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: pool ideal sequence of syt offset and data block

In current implementation, sequence of syt offset and the number of data
blocks is generated when packets for outgoing stream are going to be
queued.

This commit generates and pools the sequence independently of the
processing of outgoing packets for future extension.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20200508043635.349339-10-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: add cache for packet sequence to AMDTP domain structure

For future extension, storage is required to store packet sequence in
incoming AMDTP stream to recover media clock for outgoing AMDTP stream.

This commit adds the storage to AMDTP domain for this purpose. The
packet sequence is represented by 'struct seq_desc' which has two
members; syt_offset and the number of data blocks. The size of storage
is decided according to the size of packet queue.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20200508043635.349339-9-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: add reference to domain structure from stream structure

In current implementation, AMDTP domain structure and AMDTP stream
structure has one way of reference from the former to the latter. For
future extension, bidirectional reference is needed.

This commit adds a member into stream structure to refer to domain
structure to which the stream belongs.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20200508043635.349339-4-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: postpone to start IR context

Some devices have a quirk to postpone transmission of isoc packet for
several dozen or hundred isoc cycles since configured to transmit.
Furthermore, some devices have a quirk to transmit isoc packet with
discontinued data of its header.

In 1394 OHCI specification, software allows to start isoc context with
certain isoc cycle. Linux firewire subsystem has kernel API to use it
as well.

This commit uses the functionality of 1394 OHCI controller to handle
the quirks. At present, this feature is convenient to ALSA bebob and
fireface driver. As a result, some devices can be safely handled, as
long as I know:
- MAudio FireWire solo
- MAudio ProFire Lightbridge
- MAudio FireWire 410
- Roland FA-66

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20191018061911.24909-7-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: handle several AMDTP streams in callback handler of IRQ target

This commit changes AMDTP domain to run on an IT context of 1394 OHCI as
IRQ target. No hardware interrupt is scheduled for the other isoc
contexts. All of the isoc context are processed in a callback for an isoc
context of IRQ target.

The IRQ target is automatically selected from a list of AMDTP streams,
thus users of AMDTP domain should add an AMDTP stream for IT context
at least.

The reason to select IT context as IRQ target is that the IT context
runs on local 1394 OHCI controller and it can be used as reliable,
constant IRQ generator. On the other hand, IR context can include skip
cycle according to isoc packet transferred by device.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20191018061911.24909-6-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: replace ack callback to flush isoc contexts in AMDTP domain

An isoc context for AMDTP stream is flushed to queue packet
by a call of pcm.ack. This commit extends this for AMDTP
domain.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20191018061911.24909-4-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: replace pointer callback to flush isoc contexts in AMDTP domain

An isoc context for AMDTP stream is flushed to queue packet
by a call of pcm.pointer. This commit extends this for AMDTP
domain.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20191018061911.24909-3-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: add irq_target member into amdtp_domain struct

This commit is a preparation to handle several IR/IT contexts in the same
domain by tasklet context for one of the IT context. Such IT context is
stored to AMDTP domain structure as 'irq_target'.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20191018061911.24909-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: schedule hardware IRQ according to the size of PCM period

ALSA IEC 61883-1/6 packet streaming engine controls 1394 OHCI controller
to generate hardware IRQ for fixed number of isochronous packets (=16)
since its first commit.

This commit allow the engine to generate it for variable period according
to the number of event to handle. For outgoing stream, internal
calculator is used to check the accumulated events. For incoming stream,
the number of data block in the packet of stream is used to check the
accumulated events. When it's unavailable, fixed number of packet
roughly calculated in advance is used instead of event counting.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20191017155424.885-11-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: use variable size of queue for isoc packets instead of fixed size

The number of packets in packet buffer has been fixed number (=48) since
first commit of ALSA IEC 61883-1/6 packet streaming engine.

This commit allows the engine to use variable number of packets in the
buffer. The size is calculated by a parameter in AMDTP domain structure
surely to store the number of events in the packets of buffer. Although
the value of parameter is expected to come from 'period size' parameter
of PCM substream, at present 48 is still used.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20191017155424.885-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: add a member into AMDTP domain for events per period

In IEC 61883-6, it's called as 'event' what has presentation time
represented by timestamp in CIP header. Although the ratio of the number
of event against the number of data block is different depending on
event data type represented by the specific field in CIP header, it's
just one in the most cases supported by ALSA IEC 61883-1/6 engine.

In 1394 OHCI specification, applications can schedule hardware IRQ
by configuring descriptor with IRQ flag for packet against each
isochronous cycle. For future commit, I use the hardware IRQ for
isoc IT context to acknowledge the elapse of PCM period for both
playback/capture directions on AMDTP streams in the same domain.

This commit is a preparation for the above idea. This commit adds
a member into AMDTP domain structure to record the number of PCM frames.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20191007110532.30270-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: localize kernel APIs to start/stop each AMDTP stream

As a result to support AMDTP domain, no drivers call kernel APIs to
start/stop each AMDTP stream. This commit localize these APIs.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: add a kernel API to start AMDTP streams in AMDTP domain

This commit adds a kernel API to start a couple of isochronous contexts
for some AMDTP streams.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: add a kernel API to add AMDTP stream into AMDTP domain

This commit adds a kernel API to insert AMDTP stream to list in AMDTP
domain.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: add a kernel API to stop a couple of AMDTP streams in AMDTP domain

This commit adds a kernel API to stop a couple of isochronous contexts
for AMDTP streams. The API is not protected with any lock primitive.
Callers should use this with enough lock against concurrent access.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: add AMDTP domain structure to handle several isoc contexts

This commit adds 'struct amdtp_domain' structure. This structure
has list of instance of AMDTP stream to handle a couple of
isochronous contexts.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: process payload of isoc context according to packet descriptors

This commit changes each of data block processing layer so that it
receives list of packet descriptor.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: pass packet descriptor to data block processing layer

This commit changes signature of callback function to call data block
processing layer with packet descriptor. At present, the layer is called
per packet.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: add list of packet descriptor

In current implementation of ALSA IEC 61883-1/6 packet streaming engine,
16 packets are handled in one interrupt of isochronous context of OHCI
1394.

Overall packet processing runs for each. However, this is not better in
a point to split the processing into several parts.

This commit is an attempt to add intermediate representation for
parameters required for the parts.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: pass no syt information to data block processing layer

In a previous commit, the variable passed from packet streaming layer
for syt variable is useless. This commit obsoletes it.

In my future work, the syt information is passed to data block processing
layer by another way.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: add syt_override member for some protocols

Some protocols don't use syt field of CIP header to represent
presentation timestamp. For such protocol, ALSA IEC 61883-1/6
packet streaming engine uses a pointer into local variable for
the value of syt to call data block processing layer. However,
it can decide the value when initializing packet streaming
layer.

This commit adds 'syt_override' member for packet streaming
layer.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: pass data block counter to data block processing layer

This is a preparation for future commit that 'struct
amdtp_stream.data_block_count' does not represent the value of
data block count for current data block.

However, data block count is required for calculation of sequence index
in sequence-multiplied data channel. Some of data block processing layer
require it; e.g. for AM824 data block.

This commit passes data block count to the processing layer.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: obsolete ctx_data.tx.first_dbc with CIP_UNALIGHED_DBC flag

Recent firmware for Fireworks board module have a quirk to start
transmission of CIP with non-zero value for its data block counter.
In current implementation of ALSA firewire stack, the quirk is handled
by 'struct amdtp_stream.ctx_data.tx.first_dbc' with value 0x02. However,
the value comes from reverse engineering. It's better to handle this
quirk without the explicit value.

In a process to parse CIP header, the quirk of data block counter
affects decision of sequence index in sequence-multiplexed data channel;
i.e. MIDI conformant data channel. In Fireworks, the index is decided
by the number of data blocks from top of the same CIP, thus the value
of data block counter is useless.

This commit adds CIP_UNALIGHED_DBC flag and obsoletes the explicit
value for this quirk.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: unify packet handler for IT context

The handlers for packet with CIP and without CIP include common codes.
This commit unifies them and remove an member for pointer to callback
function from data structure.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: use 16 bytes IR context header to separate CIP header

In IR context, some quadlets of packet payload can be included into
context header. This is good for packet with CIP header because the
context payload buffer can includes data blocks only for with-CIP and
without-CIP pakets.

This commit uses 16 bytes IR context header for this purpose.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: compute pointer to payload buffer in context handler

The value of pointer to payload buffer is computed in each packet
handler, however the pointer can be decided before call of packet
handler.

This commit adds an argument for the pointer to the packet handler to
reduce codes to compute for the pointer.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: calculate the length of packet payload in packet handler

In current packet handler, the length of payload is given as an argument
of callback function, however this value is just required to process
payload of transferred isoc packet, thus just for IR context.

This commit replaces the argument for payload of packet with the
argument of context header. As a result, the length of payload is
computed in packet handler for IR context.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: use union for directional parameters

Some parameters of struct amdtp_stream is dependent on direction.

This commit uses union for such parameters to distinguish from
common parameters.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE()

Please do not apply this to mainline directly, instead please re-run the
coccinelle script shown below and apply its output.

For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't harmful, and changing them results in
churn.

However, for some features, the read/write distinction is critical to
correct operation. To distinguish these cases, separate read/write
accessors must be used. This patch migrates (most) remaining
ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
coccinelle script:

----
// Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
// WRITE_ONCE()

// $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch

virtual patch

@ depends on patch @
expression E1, E2;
@@

- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)

@ depends on patch @
expression E;
@@

- ACCESS_ONCE(E)
+ READ_ONCE(E)
----

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

ALSA: firewire-lib: Fix stall of process context at packet error

At Linux v3.5, packet processing can be done in process context of ALSA
PCM application as well as software IRQ context for OHCI 1394. Below is
an example of the callgraph (some calls are omitted).

ioctl(2) with e.g. HWSYNC
(sound/core/pcm_native.c)
->snd_pcm_common_ioctl1()
->snd_pcm_hwsync()
->snd_pcm_stream_lock_irq
(sound/core/pcm_lib.c)
->snd_pcm_update_hw_ptr()
->snd_pcm_udpate_hw_ptr0()
->struct snd_pcm_ops.pointer()
(sound/firewire/*)
= Each handler on drivers in ALSA firewire stack
(sound/firewire/amdtp-stream.c)
->amdtp_stream_pcm_pointer()
(drivers/firewire/core-iso.c)
->fw_iso_context_flush_completions()
->struct fw_card_driver.flush_iso_completion()
(drivers/firewire/ohci.c)
= flush_iso_completions()
->struct fw_iso_context.callback.sc
(sound/firewire/amdtp-stream.c)
= in_stream_callback() or out_stream_callback()
->...
->snd_pcm_stream_unlock_irq

When packet queueing error occurs or detecting invalid packets in
'in_stream_callback()' or 'out_stream_callback()', 'snd_pcm_stop_xrun()'
is called on local CPU with disabled IRQ.

(sound/firewire/amdtp-stream.c)
in_stream_callback() or out_stream_callback()
->amdtp_stream_pcm_abort()
->snd_pcm_stop_xrun()
->snd_pcm_stream_lock_irqsave()
->snd_pcm_stop()
->snd_pcm_stream_unlock_irqrestore()

The process is stalled on the CPU due to attempt to acquire recursive lock.

[ 562.630853] INFO: rcu_sched detected stalls on CPUs/tasks:
[ 562.630861] 2-...: (1 GPs behind) idle=37d/140000000000000/0 softirq=38323/38323 fqs=7140
[ 562.630862] (detected by 3, t=15002 jiffies, g=21036, c=21035, q=5933)
[ 562.630866] Task dump for CPU 2:
[ 562.630867] alsa-source-OXF R running task 0 6619 1 0x00000008
[ 562.630870] Call Trace:
[ 562.630876] ? vt_console_print+0x79/0x3e0
[ 562.630880] ? msg_print_text+0x9d/0x100
[ 562.630883] ? up+0x32/0x50
[ 562.630885] ? irq_work_queue+0x8d/0xa0
[ 562.630886] ? console_unlock+0x2b6/0x4b0
[ 562.630888] ? vprintk_emit+0x312/0x4a0
[ 562.630892] ? dev_vprintk_emit+0xbf/0x230
[ 562.630895] ? do_sys_poll+0x37a/0x550
[ 562.630897] ? dev_printk_emit+0x4e/0x70
[ 562.630900] ? __dev_printk+0x3c/0x80
[ 562.630903] ? _raw_spin_lock+0x20/0x30
[ 562.630909] ? snd_pcm_stream_lock+0x31/0x50 [snd_pcm]
[ 562.630914] ? _snd_pcm_stream_lock_irqsave+0x2e/0x40 [snd_pcm]
[ 562.630918] ? snd_pcm_stop_xrun+0x16/0x70 [snd_pcm]
[ 562.630922] ? in_stream_callback+0x3e6/0x450 [snd_firewire_lib]
[ 562.630925] ? handle_ir_packet_per_buffer+0x8e/0x1a0 [firewire_ohci]
[ 562.630928] ? ohci_flush_iso_completions+0xa3/0x130 [firewire_ohci]
[ 562.630932] ? fw_iso_context_flush_completions+0x15/0x20 [firewire_core]
[ 562.630935] ? amdtp_stream_pcm_pointer+0x2d/0x40 [snd_firewire_lib]
[ 562.630938] ? pcm_capture_pointer+0x19/0x20 [snd_oxfw]
[ 562.630943] ? snd_pcm_update_hw_ptr0+0x47/0x3d0 [snd_pcm]
[ 562.630945] ? poll_select_copy_remaining+0x150/0x150
[ 562.630947] ? poll_select_copy_remaining+0x150/0x150
[ 562.630952] ? snd_pcm_update_hw_ptr+0x10/0x20 [snd_pcm]
[ 562.630956] ? snd_pcm_hwsync+0x45/0xb0 [snd_pcm]
[ 562.630960] ? snd_pcm_common_ioctl1+0x1ff/0xc90 [snd_pcm]
[ 562.630962] ? futex_wake+0x90/0x170
[ 562.630966] ? snd_pcm_capture_ioctl1+0x136/0x260 [snd_pcm]
[ 562.630970] ? snd_pcm_capture_ioctl+0x27/0x40 [snd_pcm]
[ 562.630972] ? do_vfs_ioctl+0xa3/0x610
[ 562.630974] ? vfs_read+0x11b/0x130
[ 562.630976] ? SyS_ioctl+0x79/0x90
[ 562.630978] ? entry_SYSCALL_64_fastpath+0x1e/0xad

This commit fixes the above bug. This assumes two cases:
1. Any error is detected in software IRQ context of OHCI 1394 context.
In this case, PCM substream should be aborted in packet handler. On the
other hand, it should not be done in any process context. TO distinguish
these two context, use 'in_interrupt()' macro.
2. Any error is detect in process context of ALSA PCM application.
In this case, PCM substream should not be aborted in packet handler
because PCM substream lock is acquired. The task to abort PCM substream
should be done in ALSA PCM core. For this purpose, SNDRV_PCM_POS_XRUN is
returned at 'struct snd_pcm_ops.pointer()'.

Suggested-by: Clemens Ladisch <clemens@ladisch.de>
Fixes: e9148dddc3c7("ALSA: firewire-lib: flush completed packets when reading PCM position")
Cc: <stable@vger.kernel.org> # 4.9+
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire: process packets in 'struct snd_pcm_ops.ack' callback

In recent commit for ALSA PCM core, some arrangement is done for
'struct snd_pcm_ops.ack' callback. This is called when appl_ptr is
explicitly moved in intermediate buffer for PCM frames, except for
some cases described later.

For drivers in ALSA firewire stack, usage of this callback has a merit to
reduce latency between time of PCM frame queueing and handling actual
packets in recent isochronous cycle, because no need to wait for software
IRQ context from isochronous context of OHCI 1394.

If this works well in a case that mapped page frame is used for the
intermediate buffer, user process should execute some commands for ioctl(2)
to tell the number of handled PCM frames in the intermediate buffer just
after handling them. Therefore, at present, with a combination of below
conditions, this doesn't work as expected and user process should wait for
the software IRQ context as usual:
- when ALSA PCM core judges page frame mapping is available for status
data (struct snd_pcm_mmap_status) and control data
(struct snd_pcm_mmap_control).
- user process handles PCM frames by loop just with 'snd_pcm_mmap_begin()'
and 'snd_pcm_mmap_commit()'.
- user process uses PCM hw plugin in alsa-lib to operate I/O without
'sync_ptr_ioctl' option.

Unfortunately, major use case include these three conditions.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: cache maximum length of payload to reduce function calls

During packet streaming, maximum length of payload for isochronous packet
is invariable, therefore no need to recalculate. Current ALSA IEC 61883-1/6
engine calls a function to calculate it 8,000 or more times per second
for incoming packet processing.

This commit adds a member to have maximum length of payload into 'struct
amdtp_stream', to reduces the function calls. At first callback from
isochronous context, the length is calculated and stored for later
processing.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: add no-header packet processing

As long as investigating Fireface 400, IEC 61883-1/6 is not applied to
its packet streaming protocol. Remarks of the specific protocol are:
* Each packet doesn't include CIP headers.
* 64,0 and 128,0 kHz are supported.
* The device doesn't necessarily transmit 8,000 packets per second.
* 0, 1, 2, 3 are used as tag for rx isochronous packets, however 0 is
used for tx isochronous packets.

On the other hand, there's a common feature. The number of data blocks
transferred in a second is the same as sampling transmission frequency.
Current ALSA IEC 61883-1/6 engine already has a method to calculate it and
this driver can utilize it for rx packets, as well as tx packets.

This commit adds support for the transferring protocol. CIP_NO_HEADERS
flag is newly added. When this flag is set:
* Both of 0 (without CIP header) and 1 (with CIP header) are used as tag
to handle incoming isochronous packet.
* 0 (without CIP header) is used as tag to transfer outgoing isochronous
packet.
* Skip CIP header evaluation.
* Use unique way to calculate the quadlets of isochronous packet payload.

In ALSA PCM interface, 128.0 kHz is not supported, and the ALSA
IEC 61883-1/6 engine doesn't support 64.0 kHz. These modes are dropped.

The sequence of rx packet has a remarkable quirk about tag. This will be
described in later commits.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: add a quirk of packet without valid EOH in CIP format

In IEC 61883-1, when two quadlets CIP header is used, the most significant
bit in second CIP header stands. However, packets from units with MOTU
protocol version 3 have a quirk without this flag. Current packet streaming
layer handles this as protocol error.

This commit adds a new enumeration constant for this quirk, to handle MOTU
protocol version 3.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: enable CIP_DBC_IS_END_EVENT for both directions of stream

Commit c8bdf49b9935("ALSA: fireworks/firewire-lib: Add a quirk for the
meaning of dbc") adds CIP_DBC_IS_END_EVENT flag just for tx packets.
However, MOTU FireWire series has this quirk for rx packets.

This commit allows both directions with the flag.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: add support for source packet header field in CIP header

In IEC 61883-1, CIP headers can have a SPH field. When a packet has 1 in
SPH field of its CIP header, the packet has a source packet headers. A
source packet header consists of 32 bit field (= 1 quadlet) and it
transfers time stamp, which is the same value as the lower 25 bits of the
IEEE 1394 CYCLE_TIMER register and the rest is zero.

This commit just supports source packet header field because IEC 61883-1
includes ambiguity the position of this header and its count. Each
protocol layer is allowed to have actual implementation according its
requirements.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: record cycle count for the first packet

Currently, packet streaming layer passes generated SYT value to data block
processing layer. However, this is not enough in a case that the data block
processing layer generates time stamps by its own ways.

For out-packet stream, the packet streaming layer guarantees 8,000 times
calls of data block processing layers per sec. Therefore, when cycle count
of the first packet is recorded, data block processing layers can calculate
own time stamps with the recorded value.

For the reason, this commit allows packet streaming layer to record the
first cycle count. Each data block processing layer can read the count by
accessing a member of structure for packet streaming layer.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Revert "ALSA: firewire-lib: change structure member with proper type"

This reverts commit 6b7e95d1336b9eb0d4c6db190ce756480496bd13. This commit
is based on a concern about value of the given parameter. It's expected
to be ORed value with some enumeration-constants, thus often it can not be
one of the enumeration-constants. I understood that this is out of
specification and causes implementation-dependent issues.

In C language specification, enumerated type can be interpreted as an
integer type, in which all of enumeration-constants in corresponding
enumerator-list can be stored. Implementations can select one of char,
signed int and unsigned int as its type, and this selection is
implementation-dependent.

In GCC, a signed integer is selected when at least one of
enumeration-constants has negative value, else an unsigned integer is
selected. This behaviour can be switched by -fshort-enums to short type.
Anyway, the type can be decided after scanning all of
enumeration-constants.

Totally, there's no rules to constrain the value of enumerated type to
be one of enumeration-constants. In short, in enumerated type, decision
of actual type for the type is the most important and
enumeration-constants are just used for the decision, thus it's permitted
to have an integer value in a range of enumeration-constants. In our case,
actual type for the type is currently deterministic to be either char or
unsigned int. Under GCC, it's unsigned int.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: change structure member with proper type

The 'amdtp_stream' structure is initialized by a call of
'amdtp_stream_init()'. Although a parameter of this function is for bit
flags of packet attributes, its type is enumerator.

This commit changes the type so that it's proper for a bit flags.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: permit to flush queued packets only in process context for better PCM period granularity

These three commits were merged to improve PCM pointer granularity.
commit 76fb87894828 ("ALSA: firewire-lib: taskletize the snd_pcm_period_elapsed() call")
commit e9148dddc3c7 ("ALSA: firewire-lib: flush completed packets when reading PCM position")
commit 92b862c7d685 ("ALSA: firewire-lib: optimize packet flushing")

The point of them is to handle queued packets not only in software IRQ
context of IR/IT contexts, but also in process context. As a result of
handling packets, period tasklet is scheduled when acrossing PCM period
boundary. This is to prevent recursive call of
'struct snd_pcm_ops.pointer()' in the same context.

When the pointer callback is executed in the process context, it's
better to avoid the second callback in the software IRQ context. The
software IRQ context runs immediately after scheduled in the process
context because few packets are queued yet.

For the aim, 'pointer_flush' is used, however it causes a race condition
between the process context and software IRQ context of IR/IT contexts.

Practically, this race is not so critical because it influences process
context to skip flushing queued packet and to get worse granularity of
PCM pointer. The race condition is quite rare but it should be improved
for stable service.

The similar effect can be achieved by using 'in_interrupt()' macro. This
commit obsoletes 'pointer_flush' with it.

Acked-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: enable the same feature as CIP_SKIP_INIT_DBC_CHECK flag

In former commit, drivers in ALSA firewire stack always starts IT context
before IR context. If IR context starts after packets are transmitted by
peer unit, packet discontinuity may be detected because the context starts
in the middle of packet streaming. This situation is rare because IT
context usually starts immediately. However, it's better to solve this
issue. This is suppressed with CIP_SKIP_INIT_DBC_CHECK flag.

This commit enables the same feature as CIP_SKIP_INIT_DBC_CHECK.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: handle IT/IR contexts in each software interrupt context

In clause 6.3 of IEC 61883-6:2000, there's an explanation about processing
of presentation timestamp. In the clause, we can see "If a function block
receives a CIP, processes it and subsequently re-transmits it, then the
SYT of the outgoing CIP shall be the sum of the incoming SYT and the
processing delay." ALSA firewire stack has an implementation to partly
satisfy this specification. Developers assumed the stack to perform as an
Audio function block[1].

Following to the assumption, current implementation of ALSA firewire stack
use one software interrupt context to handle both of in/out packets. In
most case, this is processed in 1394 OHCI IR context independently of the
opposite context. Thus, this implementation uses longer CPU time in the
software interrupt context. This is not better for whole system.

Against the assumption, I confirmed that each ASIC for IEC 61883-1/6
doesn't necessarily expect it to the stack. Thus, current implementation
of ALSA firewire stack includes over-engineering.

This commit purges the implementation. As a result, packets of one
direction are handled in one software interrupt context and spends
minimum CPU time.

[1] [alsa-devel] [PATCH 0/8] [RFC] new driver for Echo Audio's Fireworks based devices
http://mailman.alsa-project.org/pipermail/alsa-devel/2013-June/062660.html

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: complete AM824 data block processing layer

This commit moves the codes related to data block processing from packet
streaming layer to AM824 layer.

Each driver initializes amdtp stream structure for AM824 data block by
calling amdtp_am824_init(). Then, a memory block is allocated for AM824
specific structure. This memory block is released by calling
amdtp_stream_destroy().

When setting streaming parameters, it calls amdtp_am824_set_parameters().
When starting packet streaming, it calls amdtp_stream_start(). When
stopping packet streaming, it calls amdtp_stream_stop().

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: rename macros with AM824 prefix

This commit renames some macros just related to AM824 format. In later
commit, they're moved to AM824 layer.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: rename PCM format helper function

Setting the format of PCM substream to AMDTP stream structure is important
to set a handler to copy actual PCM samples between buffers. The
processing should be in data block processing layer because essentially
it has no relationship to packet streaming.

This commit renames PCM format setting function to prepare for integrating
AM824 layer.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: move MIDI trigger helper function to AM824 layer

In IEC 61883-6, MIDI messages are transferred in MIDI conformant data
channel. Essentially, packet streaming layer is not responsible for MIDI
functionality.

This commit moves MIDI trigger helper function from the layer to AM824
layer. The rest of codes related to MIDI functionality will be moved in
later commits.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: rename parameter setting function for AM824 with FDF field

The value of FDF field in CIP header is protocol-dependent. Thus, it's
better to allow data block processing layer to decide the value in any
timing.

In AM824 data format, the value of FDF field in CIP header indicates
N-flag and Nominal Sampling Frequency Code (sfc). The N-flag is for
switching 'Clock-based rate control mode' and 'Command-based rate control
mode'. In our implementation, 'Clock-based rate control mode' is just
supported. Therefore, When sampling transfer frequency is decided, then
the FDF can be set.

This commit replaces 'amdtp_stream_set_parameters' with
'amdtp_am824_set_parameters' to set the FDF. This is the same timing
to decide the ration between the number of data blocks and the number of
PCM frames.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: add data block processing layer for AM824 format

This commit adds data block processing layer for AM824 format. The new
layer initializes streaming layer with its value for fmt field.

Currently, most implementation of data block processing still remains
streaming layer. In later commits, these codes will be moved to the layer.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: firewire-lib: rename 'amdtp' to 'amdtp-stream' to prepare for functional separation

In later commit, data block processing layer will be newly added. This
layer will be named as 'amdtp-am824'.

This commit renames current amdtp file to amdtp-stream, to distinguish it
from the new layer.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>