1 files changed, 34 insertions, 5 deletions

diff --git a/include/linux/firewire-cdev.h b/include/linux/firewire-cdev.h
index 357dbfc2829e..d50036953497 100644
--- a/include/linux/firewire-cdev.h
+++ b/include/linux/firewire-cdev.h
@@ -207,12 +207,16 @@ struct fw_cdev_event_request2 {
  * @closure:    See &fw_cdev_event_common;
  *              set by %FW_CDEV_CREATE_ISO_CONTEXT ioctl
  * @type:       See &fw_cdev_event_common; always %FW_CDEV_EVENT_ISO_INTERRUPT
- * @cycle:      Cycle counter of the interrupt packet
+ * @cycle:      Cycle counter of the last completed packet
  * @header_length: Total length of following headers, in bytes
  * @header:     Stripped headers, if any
  *
  * This event is sent when the controller has completed an &fw_cdev_iso_packet
- * with the %FW_CDEV_ISO_INTERRUPT bit set.
+ * with the %FW_CDEV_ISO_INTERRUPT bit set, when explicitly requested with
+ * %FW_CDEV_IOC_FLUSH_ISO, or when there have been so many completed packets
+ * without the interrupt bit set that the kernel's internal buffer for @header
+ * is about to overflow.  (In the last case, kernels with ABI version < 5 drop
+ * header data up to the next interrupt packet.)
  *
  * Isochronous transmit events (context type %FW_CDEV_ISO_CONTEXT_TRANSMIT):
  *
@@ -267,9 +271,9 @@ struct fw_cdev_event_iso_interrupt {
  *
  * This event is sent in multichannel contexts (context type
  * %FW_CDEV_ISO_CONTEXT_RECEIVE_MULTICHANNEL) for &fw_cdev_iso_packet buffer
- * chunks that have the %FW_CDEV_ISO_INTERRUPT bit set.  Whether this happens
- * when a packet is completed and/or when a buffer chunk is completed depends
- * on the hardware implementation.
+ * chunks that have been completely filled and that have the
+ * %FW_CDEV_ISO_INTERRUPT bit set, or when explicitly requested with
+ * %FW_CDEV_IOC_FLUSH_ISO.
  *
  * The buffer is continuously filled with the following data, per packet:
  *  - the 1394 iso packet header as described at &fw_cdev_event_iso_interrupt,
@@ -419,6 +423,9 @@ union fw_cdev_event {
 #define FW_CDEV_IOC_RECEIVE_PHY_PACKETS _IOW('#', 0x16, struct fw_cdev_receive_phy_packets)
 #define FW_CDEV_IOC_SET_ISO_CHANNELS    _IOW('#', 0x17, struct fw_cdev_set_iso_channels)
 
+/* available since kernel version 3.4 */
+#define FW_CDEV_IOC_FLUSH_ISO           _IOW('#', 0x18, struct fw_cdev_flush_iso)
+
 /*
  * ABI version history
  *  1  (2.6.22)  - initial version
@@ -441,6 +448,9 @@ union fw_cdev_event {
  *               - added %FW_CDEV_EVENT_ISO_INTERRUPT_MULTICHANNEL,
  *                 %FW_CDEV_ISO_CONTEXT_RECEIVE_MULTICHANNEL, and
  *                 %FW_CDEV_IOC_SET_ISO_CHANNELS
+ *  5  (3.4)     - send %FW_CDEV_EVENT_ISO_INTERRUPT events when needed to
+ *                 avoid dropping data
+ *               - added %FW_CDEV_IOC_FLUSH_ISO
  */
 
 /**
@@ -851,6 +861,25 @@ struct fw_cdev_stop_iso {
 };
 
 /**
+ * struct fw_cdev_flush_iso - flush completed iso packets
+ * @handle:     handle of isochronous context to flush
+ *
+ * For %FW_CDEV_ISO_CONTEXT_TRANSMIT or %FW_CDEV_ISO_CONTEXT_RECEIVE contexts,
+ * report any completed packets.
+ *
+ * For %FW_CDEV_ISO_CONTEXT_RECEIVE_MULTICHANNEL contexts, report the current
+ * offset in the receive buffer, if it has changed; this is typically in the
+ * middle of some buffer chunk.
+ *
+ * Any %FW_CDEV_EVENT_ISO_INTERRUPT or %FW_CDEV_EVENT_ISO_INTERRUPT_MULTICHANNEL
+ * events generated by this ioctl are sent synchronously, i.e., are available
+ * for reading from the file descriptor when this ioctl returns.
+ */
+struct fw_cdev_flush_iso {
+        __u32 handle;
+};
+
+/**
  * struct fw_cdev_get_cycle_timer - read cycle timer register
  * @local_time:   system time, in microseconds since the Epoch
  * @cycle_timer:  Cycle Time register contents