diff options
| -rw-r--r-- | include/linux/firewire-cdev.h | 35 |
1 files changed, 30 insertions, 5 deletions
diff --git a/include/linux/firewire-cdev.h b/include/linux/firewire-cdev.h index 340a78502bca..6ed9127680fd 100644 --- a/include/linux/firewire-cdev.h +++ b/include/linux/firewire-cdev.h @@ -138,7 +138,24 @@ struct fw_cdev_event_request { * This event is sent when the controller has completed an &fw_cdev_iso_packet * with the %FW_CDEV_ISO_INTERRUPT bit set. In the receive case, the headers * stripped of all packets up until and including the interrupt packet are - * returned in the @header field. + * returned in the @header field. The amount of header data per packet is as + * specified at iso context creation by &fw_cdev_create_iso_context.header_size. + * + * In version 1 of this ABI, header data consisted of the 1394 isochronous + * packet header, followed by quadlets from the packet payload if + * &fw_cdev_create_iso_context.header_size > 4. + * + * In version 2 of this ABI, header data consist of the 1394 isochronous + * packet header, followed by a timestamp quadlet if + * &fw_cdev_create_iso_context.header_size > 4, followed by quadlets from the + * packet payload if &fw_cdev_create_iso_context.header_size > 8. + * + * Behaviour of ver. 1 of this ABI is no longer available since ABI ver. 2. + * + * Format of 1394 iso packet header: 16 bits len, 2 bits tag, 6 bits channel, + * 4 bits tcode, 4 bits sy, in big endian byte order. Format of timestamp: + * 16 bits invalid, 3 bits cycleSeconds, 13 bits cycleCount, in big endian byte + * order. */ struct fw_cdev_event_iso_interrupt { __u64 closure; @@ -232,11 +249,13 @@ union fw_cdev_event { #define FW_CDEV_IOC_GET_SPEED _IOR('#', 0x11, struct fw_cdev_get_speed) #define FW_CDEV_IOC_SEND_BROADCAST_REQUEST _IOW('#', 0x12, struct fw_cdev_send_request) -/* FW_CDEV_VERSION History - * - * 1 Feb 18, 2007: Initial version. +/* + * FW_CDEV_VERSION History + * 1 (2.6.22) - initial version + * 2 (2.6.30) - changed &fw_cdev_event_iso_interrupt.header if + * &fw_cdev_create_iso_context.header_size is 8 or more */ -#define FW_CDEV_VERSION 1 +#define FW_CDEV_VERSION 2 /** * struct fw_cdev_get_info - General purpose information ioctl @@ -417,6 +436,9 @@ struct fw_cdev_remove_descriptor { * * If a context was successfully created, the kernel writes back a handle to the * context, which must be passed in for subsequent operations on that context. + * + * Note that the effect of a @header_size > 4 depends on + * &fw_cdev_get_info.version, as documented at &fw_cdev_event_iso_interrupt. */ struct fw_cdev_create_iso_context { __u32 type; @@ -520,6 +542,9 @@ struct fw_cdev_stop_iso { * 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. + * + * @cycle_timer consists of 7 bits cycleSeconds, 13 bits cycleCount, and + * 12 bits cycleOffset, in host byte order. */ struct fw_cdev_get_cycle_timer { __u64 local_time; |