In packet-per-buffer mode for isochronous context of 1394 OHCI, software
can schedule hardIRQ to the buffer in which the content of isochronous
packet is processed. The actual behaviour is different between isochronous
receive (IR) and transmit (IT) contexts in respect to isochronous cycle in
which the hardIRQ occurs.

In IR context, the hardIRQ occurs when the buffer is filled actually by
the content of received packet. If there are any isochronous cycles in
which the packet transmission is skipped, it is postponed to generate
the hardIRQ in respect to the isochronous cycle. In IT context, software
can schedule the content of packet every isochronous cycle including
skipping, therefore the hardIRQ occurs in the isochronous cycle to which
the software scheduled.

ALSA firewire stack uses the packet-per-buffer mode for both IR/IT
contexts. To process time stamp per packet (or per sample in some cases)
steadily for media clock recovery against unexpected transmission skips,
it uses an IT context to operate all of isochronous contexts by calls of
fw_iso_context_flush_completions() in the bottom-half of hardIRQ for the
IT context.

Although it looks well to handle all of isochronous contexts in a single
bottom-half context, it relatively takes longer time. In the future code
integration (not yet), it is possible to apply parallelism method to
process these context. In the case, it is useful to allow unit drivers to
schedule work items to process these isochronous contexts.

As a preparation, this commit exposes
fw_iso_context_schedule_flush_completions() as a kernel API available by
unit drivers. It is renamed from fw_iso_context_queue_work() since it is
a counter part of fw_iso_context_flush_completions().

Link: https://lore.kernel.org/r/20240908040549.75304-2-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

It is enough to notify programming mistakes to programmers just once.
Suggested-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20240905131029.6433-1-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

In the former commits, the callback of isochronous context runs on usual
work process. In the case, ALSA PCM device has a flag, nonatomic, to
acquire mutex lock instead of spin lock for PCM substream group.

This commit uses the flag. It has an advantage in the case that ALSA PCM
application uses the large size of intermediate buffer, since it takes
too long time even in tasklet softIRQ to process many of isochronous
packets, then result in the delay of system event due to disabled IRQ so
long. It is avertible to switch to nonatomic operation.
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Edmund Raile <edmund.raile@protonmail.com>
Link: https://lore.kernel.org/r/20240904125155.461886-6-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

In the former commits, the callback of isochronous context runs on work
process, thus no need to use atomic memory allocation.

This commit replaces GFP_ATOMIC with GCP_KERNEL in the callback for user
client.
Tested-by: Edmund Raile <edmund.raile@protonmail.com>
Link: https://lore.kernel.org/r/20240904125155.461886-5-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

This commit queues work item for IT/IR events at hardIRQ handler to operate
the corresponding isochronous context. The work item is queued to any of
worker-pools.

The callback for either the implementation of unit protocol and user space
clients is executed in sleepable work process context. The change could
results in any errors of concurrent processing as well as sleep at atomic
context. These errors are fixed by the following commits.
Tested-by: Edmund Raile <edmund.raile@protonmail.com>
Link: https://lore.kernel.org/r/20240904125155.461886-4-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

In the previous commit, the workqueue is added per the instance of fw_card
structure for isochronous contexts. The workqueue is designed to be used by
the implementation of fw_card_driver structure underlying the fw_card.

This commit adds some local APIs to be used by the implementation.
Tested-by: Edmund Raile <edmund.raile@protonmail.com>
Link: https://lore.kernel.org/r/20240904125155.461886-3-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

This commit adds a workqueue dedicated for isochronous context processing.

The workqueue is allocated per instance of fw_card structure to satisfy the
following characteristics descending from 1394 OHCI specification:

In 1394 OHCI specification, memory pages are reserved to each isochronous
context dedicated to DMA transmission. It allows to operate these
per-context pages concurrently. Software can schedule hardware interrupt
for several isochronous context to the same cycle, thus WQ_UNBOUND is
specified. Additionally, it is sleepable to operate the content of pages,
thus WQ_BH is not used.

The isochronous context delivers the packets with time stamp, thus
WQ_HIGHPRI is specified for semi real-time data such as IEC 61883-1/6
protocol implemented by ALSA firewire stack. The isochronous context is not
used by the implementation of SCSI over IEEE1394 protocol (sbp2), thus
WQ_MEM_RECLAIM is not specified.

It is useful for users to adjust cpu affinity of the workqueue depending
on their work loads, thus WQ_SYS is specified to expose the attributes to
user space.
Tested-by: Edmund Raile <edmund.raile@protonmail.com>
Link: https://lore.kernel.org/r/20240904125155.461886-2-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

A commit 77006a0a ("ratelimit: add comment warning people off
printk_ratelimit()") has already deprecated printk_ratelimit().

This commit uses alternative functions to obsolete its usage.

Link: https://lore.kernel.org/r/20240903101523.317110-1-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

Many tracepoints events have been added to 6.10 and 6.11 kernels. They are
available as an alternative of debug parameter in firewire-ohci module.

The logging messages enabled by the parameter require some cumbersomes in
a point of maintenance; e.g. the code to decode transaction frame.

This commit adds deprecation text to conduct users to them..

Link: https://lore.kernel.org/r/20240903101455.317067-1-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

When detecting updates of bus topology, the data of fw_device is newly
allocated and caches the content of configuration ROM from the
corresponding node. Then, the tree of device is sought to find the
previous data of fw_device corresponding to the node. If found, the
previous data is updated and reused and the data of fw_device newly
allocated is going to be released.

The above procedure is done in the call of device_find_child(), however it
is a bit abusing against the intention of the helper function, since it is
preferable to find only without updating.

This commit splits the update outside of the call.

Cc: Zijun Hu <zijun_hu@icloud.com>
Link: https://lore.kernel.org/r/20240820132132.28839-1-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

A commit 404957c1e207 ("firewire: ohci: use guard macro to serialize
accesses to phy registers") refactored initiated_reset() helper function,
while the error path was changed wrongly.

This commit fixes the bug.
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Fixes: 80f3401dfeb2 ("firewire: ohci: use guard macro to serialize accesses to phy registers")
Link: https://lore.kernel.org/r/20240817091128.180303-1-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The size of space for configuration ROM is defined by IEEE 1212. The start
and end offsets are available as some macros in UAPI header.

This commit uses these macros to compute the size.

Link: https://lore.kernel.org/r/20240814131222.69949-4-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The ohci_info() macro is a thin wrapper of dev_info(), while it is never
used.

Link: https://lore.kernel.org/r/20240814131222.69949-3-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The __aligned() macro has been available since v4.19 kernel by a commit
815f0ddb ("include/linux/compiler*.h: make compiler-*.h mutually
exclusive").

This commit replaces with the macro.

Link: https://lore.kernel.org/r/20240814131222.69949-2-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

In core function, the instances of some client resource structures are
maintained by IDR. As of kernel v6.0, IDR has been superseded by XArray
and deprecated.

This commit replaces the usage of IDR with XArray to maintain the
resource instances. The instance of XArray is allocated per client with
XA_FLAGS_ALLOC1 so that the index of allocated entry is greater than zero
and returns to user space client as handle of the resource.

Link: https://lore.kernel.org/r/20240812235210.28458-6-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

firewire: core: code refactoring to use idr_for_each_entry() macro instead of idr_for_each() function

This commit is a preparation to use xa_for_each() macro. Current
implementation uses idr_for_each() function and has a disadvantage to
replace with the macro. The IDR framework has idr_for_each_entry() macro
for the similar purpose. This commit replace the function with the
macro with minor code refactoring.

Link: https://lore.kernel.org/r/20240812235210.28458-5-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

It depends on the function assigned to release member to identify
resource structure.

This commit adds a helper function to identify iso_resource structure.

Link: https://lore.kernel.org/r/20240812235210.28458-4-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

All of local resource structure commonly have data of client_resource type
in its first member. This design sometimes requires usage of
container_of to retrieve parent structure by the first member.

This commit adds some helper functions for this purpose.

Link: https://lore.kernel.org/r/20240812235210.28458-3-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

Current implementation checks and validates the result to find resource
entry two times. It is redundant.

This commit refactors the redundancy.

Link: https://lore.kernel.org/r/20240812235210.28458-2-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The data of XArray structure includes spinlock and requires no external
lock, while the data is still under the critical section by
fw_device_rwsem.

This commit deletes the critical section.

Link: https://lore.kernel.org/r/20240812014251.165492-3-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

In core function, the instances of fw_device corresponding to firewire device
node in system are maintained by IDR. As of kernel v6.0, IDR has been
superseded by XArray and deprecated.

This commit replaces the usage of IDR with XArray to maintain the device
instances. The instance of XArray is allocated statically, and
initialized with XA_FLAGS_ALLOC so that the index of allocated entry starts
with zero and available as the minor identifier of device node.

Link: https://lore.kernel.org/r/20240812014251.165492-2-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

A commit d8527cab ("firewire: cdev: implement new event to notify
response subaction with time stamp") adds an additional case,
FW_CDEV_EVENT_RESPONSE2, into switch statement in complete_transaction().
However, the range of block is beyond to the case label and reaches
neibour default label.

This commit corrects the range of block. Fortunately, it has few impacts
in practice since the local variable in the scope under the label is not
used in codes under default label.

Fixes: d8527cab ("firewire: cdev: implement new event to notify response subaction with time stamp")
Link: https://lore.kernel.org/r/20240810070403.36801-1-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The 1394 OHCI driver uses spinlock to serialize operations for
isochronous contexts.

This commit uses guard macro to maintain the spinlock.

Link: https://lore.kernel.org/r/20240805085408.251763-18-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The 1394 OHCI driver uses spinlock for the process to update local
configuration ROM.

This commit uses guard macro to maintain the spinlock.

Link: https://lore.kernel.org/r/20240805085408.251763-17-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The 1394 OHCI driver maintains bus time to respond to querying request.
The concurrent access to the bus time is protected by spinlock.

This commit uses guard macro to maintain the spinlock.

Link: https://lore.kernel.org/r/20240805085408.251763-16-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The core functions uses spinlock in instance of fw_card structure to
protect concurrent access to properties in the instance.

This commit uses guard macro to maintain the spinlock.

Link: https://lore.kernel.org/r/20240805085408.251763-15-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The core function maintains pending asynchronous transactions by list in
the instance of fw_card. The concurrent access to the list is protected
by spinlock in the instance.

This commit uses guard macro to maintain the spinlock.

Link: https://lore.kernel.org/r/20240805085408.251763-14-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The core function maintains clients to receive phy configuration packets
by list in the instance of fw_card. The concurrent access to the list is
protected by spinlock in the instance.

This commit uses guard macro to maintain the list.

Link: https://lore.kernel.org/r/20240805085408.251763-13-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The core function allows one isochronous contexts per userspace client.
The concurrent access to the context is protected by spinlock in the
instance of client.

This commit uses guard macro to maintain the spinlock.

Link: https://lore.kernel.org/r/20240805085408.251763-12-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The core function provides UAPI to maintain isochronous resources allocated
by userspace clients across bus resets automatically. The resources are
maintained by IDR and the concurrent access to it is protected by spinlock
in the instance of client.

This commit uses guard macro to maintain the spinlock.

Link: https://lore.kernel.org/r/20240805085408.251763-11-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The core function maintains events to userspace by list in the instance of
client. The concurrent access to the list is protected by spinlock in
the instance.

This commit uses guard macro to maintain the spinlock.

Link: https://lore.kernel.org/r/20240805085408.251763-10-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The core function provides an operation for userspace application to
retrieve current value of CYCLE_TIMER register with several types of
system time. In the operation, local interrupt is disables so that the
access of the register and ktime are done atomically.

This commit uses guard macro to disable/enable local interrupts.

Link: https://lore.kernel.org/r/20240805085408.251763-9-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The core function maintains address handlers by list. It is protected by
spinlock to insert and remove entry to the list.

This commit uses guard macro to maintain the spinlock.

Link: https://lore.kernel.org/r/20240805085408.251763-8-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The core function maintains the instance of fw_device structure by IDR.
The concurrent access to IDR is protected by static read/write semaphore.
The semaphore is also utilized to protect concurrent access to the
content of configuration ROM cached to the instance so that the cache is
swapped to the latest one.

This commit uses guard macro to maintain the mutex.

Link: https://lore.kernel.org/r/20240805085408.251763-7-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The core function maintains address handlers by list. RCU is utilized
for efficient read access to any entries in the list.

This commit uses guard macro to maintain RCU locking and releasing.

Link: https://lore.kernel.org/r/20240805085408.251763-6-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The 1394 OHCI driver protects concurrent accesses to phy registers by
mutex object in fw_ohci structure.

This commit uses guard macro to maintain the mutex.

Link: https://lore.kernel.org/r/20240805085408.251763-5-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The core function maintains userspace clients by the list in fw_device
object associated to the operated character device. The concurrent
access to the list is protected by mutex in the object.

This commit uses guard macro to maintain the mutex.

Link: https://lore.kernel.org/r/20240805085408.251763-4-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The core function maintains registered cards by list. The concurrent
access to the list is protected by static mutex.

This commit uses guard macro to maintain the mutex.

Link: https://lore.kernel.org/r/20240805085408.251763-3-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

The core function provide a kernel API to send phy configuration packet.
Current implementation of the feature uses packet object allocated
statically. The concurrent access to the object is protected by static
mutex.

This commit uses guard macro to maintain the mutex.

Link: https://lore.kernel.org/r/20240805085408.251763-2-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

THis commit replaces current implementation with the helper functions added
in the former commit.

Link: https://lore.kernel.org/r/20240802003606.109402-5-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>