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authorStefan Richter <stefanr@s5r6.in-berlin.de>2010-07-18 13:00:50 +0200
committerStefan Richter <stefanr@s5r6.in-berlin.de>2010-07-23 13:36:28 +0200
commitcc550216ae9a2993ef3973464714dc1a39ab1f86 (patch)
tree62ffde836c83fe44b7a9edc01d00bcb9ad4f4ad6 /include/linux/firewire-cdev.h
parentbf54e1462b9192fdef7ea9e2bc44fdc16a4b87bc (diff)
firewire: cdev: add PHY pinging
This extends the FW_CDEV_IOC_SEND_PHY_PACKET ioctl() for /dev/fw* to be useful for ping time measurements. One application for it would be gap count optimization in userspace that is based on ping times rather than hop count. (The latter is implemented in firewire-core itself but is not applicable to beta PHYs that act as repeater.) Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Diffstat (limited to 'include/linux/firewire-cdev.h')
-rw-r--r--include/linux/firewire-cdev.h5
1 files changed, 4 insertions, 1 deletions
diff --git a/include/linux/firewire-cdev.h b/include/linux/firewire-cdev.h
index b87409160794..da0fec7e8dc0 100644
--- a/include/linux/firewire-cdev.h
+++ b/include/linux/firewire-cdev.h
@@ -294,7 +294,10 @@ struct fw_cdev_event_iso_resource {
* @length: Data length in bytes
* @data: Incoming data
*
- * If @type is %FW_CDEV_EVENT_PHY_PACKET_SENT, @length is 0 and @data empty.
+ * If @type is %FW_CDEV_EVENT_PHY_PACKET_SENT, @length is 0 and @data empty,
+ * except in case of a ping packet: Then, @length is 4, and @data[0] is the
+ * ping time in 49.152MHz clocks if @rcode is %RCODE_COMPLETE.
+ *
* If @type is %FW_CDEV_EVENT_PHY_PACKET_RECEIVED, @length is 8 and @data
* consists of the two PHY packet quadlets, in host byte order.
*/