firewire: adopt read cycle timer ABI from raw1394

This duplicates the read cycle timer feature of raw1394 (added in Linux
2.6.21) in firewire-core's userspace ABI.  The argument to the ioctl is
reordered though to ensure 32/64 bit compatibility.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Kristian Høgsberg <krh@redhat.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/include/linux/firewire-cdev.h b/include/linux/firewire-cdev.h
index 1a45d6f41b09..0f0e271f97fa 100644
--- a/include/linux/firewire-cdev.h
+++ b/include/linux/firewire-cdev.h
@@ -178,6 +178,7 @@ union fw_cdev_event {
 #define FW_CDEV_IOC_QUEUE_ISO           _IOWR('#', 0x09, struct fw_cdev_queue_iso)
 #define FW_CDEV_IOC_START_ISO           _IOW('#', 0x0a, struct fw_cdev_start_iso)
 #define FW_CDEV_IOC_STOP_ISO            _IOW('#', 0x0b, struct fw_cdev_stop_iso)
+#define FW_CDEV_IOC_GET_CYCLE_TIMER     _IOR('#', 0x0c, struct fw_cdev_get_cycle_timer)
 
 /* FW_CDEV_VERSION History
  *
@@ -459,4 +460,18 @@ struct fw_cdev_stop_iso {
         __u32 handle;
 };
 
+/**
+ * struct fw_cdev_get_cycle_timer - read cycle timer register
+ * @local_time:   system time, in microseconds since the Epoch
+ * @cycle_timer:  isochronous cycle timer, as per OHCI 1.1 clause 5.13
+ *
+ * The %FW_CDEV_IOC_GET_CYCLE_TIMER ioctl reads the isochronous cycle timer
+ * and also the system clock.  This allows to express the receive time of an
+ * isochronous packet as a system time with microsecond accuracy.
+ */
+struct fw_cdev_get_cycle_timer {
+        __u64 local_time;
+        __u32 cycle_timer;
+};
+
 #endif /* _LINUX_FIREWIRE_CDEV_H */