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firewire: net: Use posted writes 

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>
This commit is contained in:
Stephan Gatzka 2011-09-26 21:44:30 +02:00 committed by Stefan Richter
parent 4ec4a67aa1
commit a74477db91
2 changed files with 4 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
drivers/firewire/net.c
View File

@ -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;

3
drivers/firewire/ohci.c
View File

@ -2045,7 +2045,8 @@ static irqreturn_t irq_handler(int irq, void *data)
reg_read(ohci, OHCI1394_PostedWriteAddressLo);
reg_write(ohci, OHCI1394_IntEventClear,
OHCI1394_postedWriteErr);
fw_error("PCI posted write error\n");
if (printk_ratelimit())
fw_error("PCI posted write error\n");
}
if (unlikely(event & OHCI1394_cycleTooLong)) {