From dcadfd7f7c74ef9ee415e072a19bdf6c085159eb Mon Sep 17 00:00:00 2001 From: Takashi Sakamoto Date: Tue, 30 May 2023 08:12:40 +0900 Subject: firewire: core: use union for callback of transaction completion In 1394 OHCI, the OUTPUT_LAST descriptor of Asynchronous Transmit (AT) request context has timeStamp field, in which 1394 OHCI controller record the isochronous cycle when the packet was sent for the request subaction. Additionally, for the case of split transaction in IEEE 1394, Asynchronous Receive (AT) request context is used for response subaction to finish the transaction. The trailer quadlet of descriptor in the context has timeStamp field, in which 1394 OHCI controller records the isochronous cycle when the packet arrived. Current implementation of 1394 OHCI controller driver stores values of both fields to internal structure as time stamp, while Linux FireWire subsystem provides no way to access to it. When using asynchronous transaction service provided by the subsystem, callback function is passed to kernel API. The prototype of callback function has the lack of argument for the values. This commit adds a new callback function for the purpose. It has an additional argument to point to the constant array with two elements. For backward compatibility to kernel space, a new union is also adds to wrap two different prototype of callback function. The fw_transaction structure has the union as a member and a boolean flag to express which function callback is available. The core function is changed to handle the two cases; with or without time stamp. For the error path to process transaction, the isochronous cycle is computed by current value of CYCLE_TIMER register in 1394 OHCI controller. Especially for the case of timeout of split transaction, the expected isochronous cycle is computed. Link: https://lore.kernel.org/r/20230529113406.986289-6-o-takashi@sakamocchi.jp Signed-off-by: Takashi Sakamoto --- drivers/firewire/ohci.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) (limited to 'drivers/firewire/ohci.c') diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c index 17c9d825188b..06386c3b7f03 100644 --- a/drivers/firewire/ohci.c +++ b/drivers/firewire/ohci.c @@ -1623,6 +1623,8 @@ static void handle_local_request(struct context *ctx, struct fw_packet *packet) } } +static u32 get_cycle_time(struct fw_ohci *ohci); + static void at_context_transmit(struct context *ctx, struct fw_packet *packet) { unsigned long flags; @@ -1633,6 +1635,10 @@ static void at_context_transmit(struct context *ctx, struct fw_packet *packet) if (HEADER_GET_DESTINATION(packet->header[0]) == ctx->ohci->node_id && ctx->ohci->generation == packet->generation) { spin_unlock_irqrestore(&ctx->ohci->lock, flags); + + // Timestamping on behalf of the hardware. + packet->timestamp = cycle_time_to_ohci_tstamp(get_cycle_time(ctx->ohci)); + handle_local_request(ctx, packet); return; } @@ -1640,9 +1646,12 @@ static void at_context_transmit(struct context *ctx, struct fw_packet *packet) ret = at_context_queue_packet(ctx, packet); spin_unlock_irqrestore(&ctx->ohci->lock, flags); - if (ret < 0) - packet->callback(packet, &ctx->ohci->card, packet->ack); + if (ret < 0) { + // Timestamping on behalf of the hardware. + packet->timestamp = cycle_time_to_ohci_tstamp(get_cycle_time(ctx->ohci)); + packet->callback(packet, &ctx->ohci->card, packet->ack); + } } static void detect_dead_context(struct fw_ohci *ohci, @@ -2557,6 +2566,10 @@ static int ohci_cancel_packet(struct fw_card *card, struct fw_packet *packet) log_ar_at_event(ohci, 'T', packet->speed, packet->header, 0x20); driver_data->packet = NULL; packet->ack = RCODE_CANCELLED; + + // Timestamping on behalf of the hardware. + packet->timestamp = cycle_time_to_ohci_tstamp(get_cycle_time(ohci)); + packet->callback(packet, &ohci->card, packet->ack); ret = 0; out: -- cgit v1.2.3