diff options
| author |   Takashi Sakamoto <o-takashi@sakamocchi.jp> | 2024-09-04 21:51:50 +0900 |
|---|---|---|
| committer | Takashi Sakamoto <o-takashi@sakamocchi.jp> | 2024-09-04 21:51:50 +0900 |
| commit | c6fb88a5270f4ba24859f5ecb61cfc731ef16300 (patch) | |
| tree | 19f47ec8e4fc3fc44e7e8c7c853fa8b55bcc4894 /include/linux/firewire.h | |
| parent | firewire: ohci: obsolete direct usage of printk_ratelimit() (diff) | |
| download | wireguard-linux-c6fb88a5270f4ba24859f5ecb61cfc731ef16300.tar.xz wireguard-linux-c6fb88a5270f4ba24859f5ecb61cfc731ef16300.zip | |
firewire: core: allocate workqueue to handle isochronous contexts in card
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.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Diffstat (limited to '')
| -rw-r--r-- | include/linux/firewire.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/firewire.h b/include/linux/firewire.h index 1cca14cf5652..10e135d60824 100644 --- a/include/linux/firewire.h +++ b/include/linux/firewire.h @@ -134,6 +134,8 @@ struct fw_card { __be32 topology_map[(CSR_TOPOLOGY_MAP_END - CSR_TOPOLOGY_MAP) / 4]; __be32 maint_utility_register; + + struct workqueue_struct *isoc_wq; }; static inline struct fw_card *fw_card_get(struct fw_card *card) |