kernel/linux.git/drivers/firewire/ohci.c, branch v6.12.80

firewire: ohci: move self_id_complete tracepoint after validating register

2025-11-13T20:34:03+00:00

[ Upstream commit 696968262aeee51e1c0529c3c060ddd180702e02 ] The value of OHCI1394_SelfIDCount register includes an error-indicating bit. It is safer to place the tracepoint probe after validating the register value. Link: https://lore.kernel.org/r/20250823030954.268412-2-o-takashi@sakamocchi.jp Signed-off-by: Takashi Sakamoto Signed-off-by: Sasha Levin

firewire: core: rename cause flag of tracepoints event

2024-09-12T13:30:38+00:00

The flag of FW_ISO_CONTEXT_COMPLETIONS_CAUSE_IRQ directly causes hardIRQ request by 1394 OHCI hardware when the corresponding isochronous packet is transferred, however it is not so directly associated to hardIRQ processing itself. This commit renames the flag so that it relates to interrupt parameter of internal packet data. Link: https://lore.kernel.org/r/20240912133038.238786-6-o-takashi@sakamocchi.jp Signed-off-by: Takashi Sakamoto

firewire: core: add helper function to retire descriptors

2024-09-12T13:30:36+00:00

Both IR/IT contexts use the same code to retire completed descriptors as AT context uses. This commit adds a helper function to reduce the duplicated codes. Link: https://lore.kernel.org/r/20240912133038.238786-4-o-takashi@sakamocchi.jp Signed-off-by: Takashi Sakamoto

Revert "firewire: core: move workqueue handler from 1394 OHCI driver to core function"

2024-09-12T13:30:35+00:00

This reverts commit 767bfb9ef27ebf760290d9f8bc303828b018c312. It appears that the call of ohci_flush_iso_completions() in the work item scheduled by hardIRQ of 1394 OHCI for any isochronous context changes the timing to queue events in the view of user space application. Link: https://lore.kernel.org/r/20240912133038.238786-3-o-takashi@sakamocchi.jp Signed-off-by: Takashi Sakamoto

Revert "firewire: core: use mutex to coordinate concurrent calls to flush completions"

2024-09-12T13:30:34+00:00

This reverts commit d9605d67562505e27dcc0f71af418118d3db91e5, since this commit is on the following reverted changes. Link: https://lore.kernel.org/r/20240912133038.238786-2-o-takashi@sakamocchi.jp Signed-off-by: Takashi Sakamoto

firewire: core: use mutex to coordinate concurrent calls to flush completions

2024-09-09T14:00:18+00:00

In current implementation, test_and_set_bit_lock() is used to mediate concurrent calls of ohci_flush_iso_completions(). However, the ad-hoc usage of atomic operations is not preferable. This commit uses mutex_trylock() as the similar operations. The core function is responsible for the mediation, instead of 1394 OHCI driver. Link: https://lore.kernel.org/r/20240909140018.65289-3-o-takashi@sakamocchi.jp Signed-off-by: Takashi Sakamoto

firewire: core: move workqueue handler from 1394 OHCI driver to core function

2024-09-09T14:00:17+00:00

In current implementation, the work item for isochronous context executes the same procedure of fw_iso_context_flush_completions() internally. There is a space to refactor the implementation. This commit calls fw_iso_context_flush_completions() in the work item. It obsoletes fw_iso_context_init_work(). It also obsoletes a pair of disable_work_sync() and enable_work() since the usage of test_and_set_bit_lock() mediates concurrent call already. Link: https://lore.kernel.org/r/20240909140018.65289-2-o-takashi@sakamocchi.jp Signed-off-by: Takashi Sakamoto

firewire: core: expose kernel API to schedule work item to process isochronous context

2024-09-08T04:05:48+00:00

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.jp Signed-off-by: Takashi Sakamoto

firewire: ohci: operate IT/IR events in sleepable work process instead of tasklet softIRQ

2024-09-04T12:51:52+00:00

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 Link: https://lore.kernel.org/r/20240904125155.461886-4-o-takashi@sakamocchi.jp Signed-off-by: Takashi Sakamoto

firewire: core: allocate workqueue to handle isochronous contexts in card

2024-09-04T12:51:50+00:00

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 Link: https://lore.kernel.org/r/20240904125155.461886-2-o-takashi@sakamocchi.jp Signed-off-by: Takashi Sakamoto