diff options
| -rw-r--r-- | Documentation/ABI/stable/firewire-cdev | 103 | ||||
| -rw-r--r-- | include/linux/firewire-cdev.h | 75 |
2 files changed, 137 insertions, 41 deletions
diff --git a/Documentation/ABI/stable/firewire-cdev b/Documentation/ABI/stable/firewire-cdev new file mode 100644 index 00000000000..16d03082736 --- /dev/null +++ b/Documentation/ABI/stable/firewire-cdev @@ -0,0 +1,103 @@ +What: /dev/fw[0-9]+ +Date: May 2007 +KernelVersion: 2.6.22 +Contact: linux1394-devel@lists.sourceforge.net +Description: + The character device files /dev/fw* are the interface between + firewire-core and IEEE 1394 device drivers implemented in + userspace. The ioctl(2)- and read(2)-based ABI is defined and + documented in <linux/firewire-cdev.h>. + + This ABI offers most of the features which firewire-core also + exposes to kernelspace IEEE 1394 drivers. + + Each /dev/fw* is associated with one IEEE 1394 node, which can + be remote or local nodes. Operations on a /dev/fw* file have + different scope: + - The 1394 node which is associated with the file: + - Asynchronous request transmission + - Get the Configuration ROM + - Query node ID + - Query maximum speed of the path between this node + and local node + - The 1394 bus (i.e. "card") to which the node is attached to: + - Isochronous stream transmission and reception + - Asynchronous stream transmission and reception + - Asynchronous broadcast request transmission + - PHY packet transmission and reception + - Allocate, reallocate, deallocate isochronous + resources (channels, bandwidth) at the bus's IRM + - Query node IDs of local node, root node, IRM, bus + manager + - Query cycle time + - Bus reset initiation, bus reset event reception + - All 1394 buses: + - Allocation of IEEE 1212 address ranges on the local + link layers, reception of inbound requests to such + an address range, asynchronous response transmission + to inbound requests + - Addition of descriptors or directories to the local + nodes' Configuration ROM + + Due to the different scope of operations and in order to let + userland implement different access permission models, some + operations are restricted to /dev/fw* files that are associated + with a local node: + - Addition of descriptors or directories to the local + nodes' Configuration ROM + - PHY packet transmission and reception + + A /dev/fw* file remains associated with one particular node + during its entire life time. Bus topology changes, and hence + node ID changes, are tracked by firewire-core. ABI users do not + need to be aware of topology. + + The following file operations are supported: + + open(2) + Currently the only useful flags are O_RDWR. + + ioctl(2) + Initiate various actions. Some take immediate effect, others + are performed asynchronously while or after the ioctl returns. + See the inline documentation in <linux/firewire-cdev.h> for + descriptions of all ioctls. + + poll(2), select(2), epoll_wait(2) etc. + Watch for events to become available to be read. + + read(2) + Receive various events. There are solicited events like + outbound asynchronous transaction completion or isochronous + buffer completion, and unsolicited events such as bus resets, + request reception, or PHY packet reception. Always use a read + buffer which is large enough to receive the largest event that + could ever arrive. See <linux/firewire-cdev.h> for descriptions + of all event types and for which ioctls affect reception of + events. + + mmap(2) + Allocate a DMA buffer for isochronous reception or transmission + and map it into the process address space. The arguments should + be used as follows: addr = NULL, length = the desired buffer + size, i.e. number of packets times size of largest packet, + prot = at least PROT_READ for reception and at least PROT_WRITE + for transmission, flags = MAP_SHARED, fd = the handle to the + /dev/fw*, offset = 0. + + Isochronous reception works in packet-per-buffer fashion except + for multichannel reception which works in buffer-fill mode. + + munmap(2) + Unmap the isochronous I/O buffer from the process address space. + + close(2) + Besides stopping and freeing I/O contexts that were associated + with the file descriptor, back out any changes to the local + nodes' Configuration ROM. Deallocate isochronous channels and + bandwidth at the IRM that were marked for kernel-assisted + re- and deallocation. + +Users: libraw1394 + libdc1394 + tools like jujuutils, fwhack, ... diff --git a/include/linux/firewire-cdev.h b/include/linux/firewire-cdev.h index 55814aa33be..357dbfc2829 100644 --- a/include/linux/firewire-cdev.h +++ b/include/linux/firewire-cdev.h @@ -30,10 +30,13 @@ #include <linux/types.h> #include <linux/firewire-constants.h> +/* available since kernel version 2.6.22 */ #define FW_CDEV_EVENT_BUS_RESET 0x00 #define FW_CDEV_EVENT_RESPONSE 0x01 #define FW_CDEV_EVENT_REQUEST 0x02 #define FW_CDEV_EVENT_ISO_INTERRUPT 0x03 + +/* available since kernel version 2.6.30 */ #define FW_CDEV_EVENT_ISO_RESOURCE_ALLOCATED 0x04 #define FW_CDEV_EVENT_ISO_RESOURCE_DEALLOCATED 0x05 @@ -120,24 +123,11 @@ struct fw_cdev_event_response { /** * struct fw_cdev_event_request - Old version of &fw_cdev_event_request2 - * @closure: See &fw_cdev_event_common; set by %FW_CDEV_IOC_ALLOCATE ioctl * @type: See &fw_cdev_event_common; always %FW_CDEV_EVENT_REQUEST - * @tcode: See &fw_cdev_event_request2 - * @offset: See &fw_cdev_event_request2 - * @handle: See &fw_cdev_event_request2 - * @length: See &fw_cdev_event_request2 - * @data: See &fw_cdev_event_request2 * * This event is sent instead of &fw_cdev_event_request2 if the kernel or - * the client implements ABI version <= 3. - * - * Unlike &fw_cdev_event_request2, the sender identity cannot be established, - * broadcast write requests cannot be distinguished from unicast writes, and - * @tcode of lock requests is %TCODE_LOCK_REQUEST. - * - * Requests to the FCP_REQUEST or FCP_RESPONSE register are responded to as - * with &fw_cdev_event_request2, except in kernel 2.6.32 and older which send - * the response packet of the client's %FW_CDEV_IOC_SEND_RESPONSE ioctl. + * the client implements ABI version <= 3. &fw_cdev_event_request lacks + * essential information; use &fw_cdev_event_request2 instead. */ struct fw_cdev_event_request { __u64 closure; @@ -452,30 +442,29 @@ union fw_cdev_event { * %FW_CDEV_ISO_CONTEXT_RECEIVE_MULTICHANNEL, and * %FW_CDEV_IOC_SET_ISO_CHANNELS */ -#define FW_CDEV_VERSION 3 /* Meaningless; don't use this macro. */ /** * struct fw_cdev_get_info - General purpose information ioctl * @version: The version field is just a running serial number. Both an * input parameter (ABI version implemented by the client) and * output parameter (ABI version implemented by the kernel). - * A client must not fill in an %FW_CDEV_VERSION defined from an - * included kernel header file but the actual version for which - * the client was implemented. This is necessary for forward - * compatibility. We never break backwards compatibility, but - * may add more structs, events, and ioctls in later revisions. - * @rom_length: If @rom is non-zero, at most rom_length bytes of configuration + * A client shall fill in the ABI @version for which the client + * was implemented. This is necessary for forward compatibility. + * @rom_length: If @rom is non-zero, up to @rom_length bytes of Configuration * ROM will be copied into that user space address. In either * case, @rom_length is updated with the actual length of the - * configuration ROM. + * Configuration ROM. * @rom: If non-zero, address of a buffer to be filled by a copy of the - * device's configuration ROM + * device's Configuration ROM * @bus_reset: If non-zero, address of a buffer to be filled by a * &struct fw_cdev_event_bus_reset with the current state * of the bus. This does not cause a bus reset to happen. * @bus_reset_closure: Value of &closure in this and subsequent bus reset events * @card: The index of the card this device belongs to * + * The %FW_CDEV_IOC_GET_INFO ioctl is usually the very first one which a client + * performs right after it opened a /dev/fw* file. + * * As a side effect, reception of %FW_CDEV_EVENT_BUS_RESET events to be read(2) * is started by this ioctl. */ @@ -615,7 +604,7 @@ struct fw_cdev_initiate_bus_reset { * @handle: Handle to the descriptor, written by the kernel * * Add a descriptor block and optionally a preceding immediate key to the local - * node's configuration ROM. + * node's Configuration ROM. * * The @key field specifies the upper 8 bits of the descriptor root directory * pointer and the @data and @length fields specify the contents. The @key @@ -630,9 +619,9 @@ struct fw_cdev_initiate_bus_reset { * If successful, the kernel adds the descriptor and writes back a @handle to * the kernel-side object to be used for later removal of the descriptor block * and immediate key. The kernel will also generate a bus reset to signal the - * change of the configuration ROM to other nodes. + * change of the Configuration ROM to other nodes. * - * This ioctl affects the configuration ROMs of all local nodes. + * This ioctl affects the Configuration ROMs of all local nodes. * The ioctl only succeeds on device files which represent a local node. */ struct fw_cdev_add_descriptor { @@ -644,13 +633,13 @@ struct fw_cdev_add_descriptor { }; /** - * struct fw_cdev_remove_descriptor - Remove contents from the configuration ROM + * struct fw_cdev_remove_descriptor - Remove contents from the Configuration ROM * @handle: Handle to the descriptor, as returned by the kernel when the * descriptor was added * * Remove a descriptor block and accompanying immediate key from the local - * nodes' configuration ROMs. The kernel will also generate a bus reset to - * signal the change of the configuration ROM to other nodes. + * nodes' Configuration ROMs. The kernel will also generate a bus reset to + * signal the change of the Configuration ROM to other nodes. */ struct fw_cdev_remove_descriptor { __u32 handle; @@ -866,13 +855,8 @@ struct fw_cdev_stop_iso { * @local_time: system time, in microseconds since the Epoch * @cycle_timer: Cycle Time register contents * - * The %FW_CDEV_IOC_GET_CYCLE_TIMER ioctl reads the isochronous cycle timer - * and also the system clock (%CLOCK_REALTIME). This allows to express the - * receive time of an isochronous packet as a system time. - * - * @cycle_timer consists of 7 bits cycleSeconds, 13 bits cycleCount, and - * 12 bits cycleOffset, in host byte order. Cf. the Cycle Time register - * per IEEE 1394 or Isochronous Cycle Timer register per OHCI-1394. + * Same as %FW_CDEV_IOC_GET_CYCLE_TIMER2, but fixed to use %CLOCK_REALTIME + * and only with microseconds resolution. * * In version 1 and 2 of the ABI, this ioctl returned unreliable (non- * monotonic) @cycle_timer values on certain controllers. @@ -889,10 +873,17 @@ struct fw_cdev_get_cycle_timer { * @clk_id: input parameter, clock from which to get the system time * @cycle_timer: Cycle Time register contents * - * The %FW_CDEV_IOC_GET_CYCLE_TIMER2 works like - * %FW_CDEV_IOC_GET_CYCLE_TIMER but lets you choose a clock like with POSIX' - * clock_gettime function. Supported @clk_id values are POSIX' %CLOCK_REALTIME - * and %CLOCK_MONOTONIC and Linux' %CLOCK_MONOTONIC_RAW. + * The %FW_CDEV_IOC_GET_CYCLE_TIMER2 ioctl reads the isochronous cycle timer + * and also the system clock. This allows to correlate reception time of + * isochronous packets with system time. + * + * @clk_id lets you choose a clock like with POSIX' clock_gettime function. + * Supported @clk_id values are POSIX' %CLOCK_REALTIME and %CLOCK_MONOTONIC + * and Linux' %CLOCK_MONOTONIC_RAW. + * + * @cycle_timer consists of 7 bits cycleSeconds, 13 bits cycleCount, and + * 12 bits cycleOffset, in host byte order. Cf. the Cycle Time register + * per IEEE 1394 or Isochronous Cycle Timer register per OHCI-1394. */ struct fw_cdev_get_cycle_timer2 { __s64 tv_sec; @@ -1014,4 +1005,6 @@ struct fw_cdev_receive_phy_packets { __u64 closure; }; +#define FW_CDEV_VERSION 3 /* Meaningless legacy macro; don't use it. */ + #endif /* _LINUX_FIREWIRE_CDEV_H */ |