firewire: add kernel API to access packet structure in request structure for AR context

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In 1394 OHCI specification, descriptor of Asynchronous Receive DMA context
has timeStamp field in its trailer quadlet. The field is written by
the host controller for the time to receive asynchronous request
subaction in isochronous cycle time.

In Linux FireWire subsystem, the value of field is stored to fw_packet
structure and copied to fw_request structure as the part. The fw_request
structure is hidden from unit driver and passed as opaque pointer when
calling registered handler. It's inconvenient to the unit driver which
needs timestamp of packet.

This commit adds kernel API to pick up timestamp from opaque pointer to
fw_request structure.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20220405072221.226217-4-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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Takashi Sakamoto 2022-04-05 16:22:21 +09:00 • committed by Takashi Iwai

parent baa914cd81

commit b2405aa948

2 changed files with 19 additions and 0 deletions

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18

drivers/firewire/core-transaction.c

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1

include/linux/firewire.h

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