firewire: net: Use posted writes (a74477db) · Commits · 戴 / test

Change memory region to ohci "middle address space". This effectively reduces the number of packets by 50%. [Stefan R.:] This eliminates 1394 ack packets and improved throughput by a few percent in some tests with an S400a connection with and without gap count optimization. Since firewire-net taxes the AR-req DMA unit of a FireWire controller much more than firewire-sbp2 (which uses the middle address space with PCI posted writes too), this commit also changes a related error printk into a ratelimited one as a precaution. Side note: The IPv4-over-1394 drivers of Mac OS X 10.4, Windows XP SP3, and the Thesycon 1394 bus driver for Windows all use the middle address space too. Signed-off-by:

Stephan Gatzka <stephan@gatzka.org> Signed-off-by:

Stefan Richter <stefanr@s5r6.in-berlin.de>

drivers/firewire/net.c

+2 −7

Original line number	Diff line number	Diff line
		@@ -1121,17 +1121,12 @@ static int fwnet_broadcast_start(struct fwnet_device *dev)
		unsigned u;

		if (dev->local_fifo == FWNET_NO_FIFO_ADDR) {
		/* outside OHCI posted write area? */
		static const struct fw_address_region region = {
		.start = 0xffff00000000ULL,
		.end = CSR_REGISTER_BASE,
		};

		dev->handler.length = 4096;
		dev->handler.address_callback = fwnet_receive_packet;
		dev->handler.callback_data = dev;

		retval = fw_core_add_address_handler(&dev->handler, &region);
		retval = fw_core_add_address_handler(&dev->handler,
		&fw_high_memory_region);
		if (retval < 0)
		goto failed_initial;

drivers/firewire/ohci.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -2045,6 +2045,7 @@ static irqreturn_t irq_handler(int irq, void *data)
		reg_read(ohci, OHCI1394_PostedWriteAddressLo);
		reg_write(ohci, OHCI1394_IntEventClear,
		OHCI1394_postedWriteErr);
		if (printk_ratelimit())
		fw_error("PCI posted write error\n");
		}

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