firewire: cdev: implement new event to notify request subaction with time stamp

In 1394 OHCI, the trailer quadlet of descriptor in Asynchronous Receive
(AR) request context has timeStamp field, in which the 1394 OHCI
controller record the isochronous cycle when the packet arrived.

Current implementation of 1394 OHCI controller driver stores the value
of field to internal structure as time stamp, while the implementation
of FireWire character device doesn't have a field for the time stamp,
thus it is not available in user space. The time stamp is convenient to
some kind of application in which data from several sources are compared
in isochronous cycle unit.

This commit implement the new event, fw_cdev_event_request3, with an
additional field, tstamp.

Link: https://lore.kernel.org/r/20230529113406.986289-5-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

1 files changed, 17 insertions, 1 deletions

diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c
index 88c8b5fac5e5..5a9446d30447 100644
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -178,6 +178,7 @@ struct inbound_transaction_event {
 	union {
 		struct fw_cdev_event_request request;
 		struct fw_cdev_event_request2 request2;
+		struct fw_cdev_event_request3 with_tstamp;
 	} req;
 };
 
@@ -709,7 +710,7 @@ static void handle_request(struct fw_card *card, struct fw_request *request,
 		req->handle	= r->resource.handle;
 		req->closure	= handler->closure;
 		event_size0	= sizeof(*req);
-	} else {
+	} else if (handler->client->version < FW_CDEV_VERSION_EVENT_ASYNC_TSTAMP) {
 		struct fw_cdev_event_request2 *req = &e->req.request2;
 
 		req->type	= FW_CDEV_EVENT_REQUEST2;
@@ -723,6 +724,21 @@ static void handle_request(struct fw_card *card, struct fw_request *request,
 		req->handle	= r->resource.handle;
 		req->closure	= handler->closure;
 		event_size0	= sizeof(*req);
+	} else {
+		struct fw_cdev_event_request3 *req = &e->req.with_tstamp;
+
+		req->type	= FW_CDEV_EVENT_REQUEST3;
+		req->tcode	= tcode;
+		req->offset	= offset;
+		req->source_node_id = source;
+		req->destination_node_id = destination;
+		req->card	= card->index;
+		req->generation	= generation;
+		req->length	= length;
+		req->handle	= r->resource.handle;
+		req->closure	= handler->closure;
+		req->tstamp	= fw_request_get_timestamp(request);
+		event_size0	= sizeof(*req);
 	}
 
 	queue_event(handler->client, &e->event,