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<book>
<bookinfo>
<title>libraw1394</title>
<subtitle>version 2.0.4</subtitle>
<copyright>
<year>2001-2009</year>
<holder>Andreas Bombe, Dan Maas, Manfred Weihs, and Christian Toegel</holder>
</copyright>
</bookinfo>
<toc></toc>
<chapter id="introduction">
<title>Introduction</title>
<para>
The Linux kernel's IEEE 1394 subsystem provides access to the raw 1394 bus
through the raw1394 module. This includes the standard 1394 transactions
(read, write, lock) on the active side, isochronous stream receiving and
sending and dumps of data written to the FCP_COMMAND and FCP_RESPONSE
registers. raw1394 uses a character device to communicate to user
programs using a special protocol.
</para>
<para>
libraw1394 was created with the intent to hide that protocol from
applications so that
<orderedlist numeration="arabic">
<listitem>
<para>
the protocol has to be implemented correctly only once.
</para>
</listitem>
<listitem>
<para>
all work can be done using easy to understand functions instead of
handling a complicated command structure.
</para>
</listitem>
<listitem>
<para>
only libraw1394 has to be changed when raw1394's interface changes.
</para>
</listitem>
</orderedlist>
</para>
<para>
To fully achieve the goals (especially 3) libraw1394 is distributed under
the LGPL (Lesser General Public License - see file COPYING.LIB for more
information.) to allow linking with any program, be it open source or
binary only. The requirements are that the libraw1394 part can be
replaced (relinked) with another version of the library and that changes
to libraw1394 itself fall under LGPL again. Refer to the LGPL text for
details.
</para>
</chapter>
<chapter id="intro1394">
<title>Short Introduction into IEEE 1394</title>
<para>
IEEE 1394 in fact defines two types of hardware implementations for this
bus system, cable and backplane. The only one described here and
supported by the Linux subsystem is the cable implementation. Most people
not familiar with the standard probably don't even know that there is
something else than the 1394 cable specification.
</para>
<para>
If you are familiar with CSR architectures (as defined in ISO/IEC 13213
(ANSI/IEEE 1212)), then you already know quite a bit of 1394, which is a
CSR implementation.
</para>
<sect1>
<title>Bus Structure</title>
<para>
The basic data structures defined in the standard and used in this
document are the quadlet (32 bit quantity) and the octlet (64 bit
quantity) and blocks (any quantity of bytes). The bus byte ordering is
big endian. A transmission can be sent at one of multiple possible
speeds, which are 100, 200 and 400 Mbit/s for the currently mostly used
IEEE 1394a spec and up to 3.2 Gbit/s in the recently finalized 1394.b
standard (these speeds are also referred to as S100, S200, ...).
</para>
<para>
A 1394 bus consists of up to 64 nodes (with multiple buses possibly
being connected, but that is outside of the scope of this document and
not completely standardized yet). Each node is addressed with a 16 bit
address, which is further divided into a 10 bit bus ID and a 6 bit local
node number, the so-called physical ID. The physical IDs are completely
dynamic and determined during the bus reset. The highest values for
both are special values. Bus ID equal to 1023 means "local bus" (the
bus the node is connected to), physical ID equal to 63 means "all nodes"
(broadcast).
</para>
<para>
The local bus ID 1023 is the only one that can be used unless IEEE
1394.1 bridge portals to more buses were available. Therefore the node
IDs have to be given as (1023&lt;&lt;6) | phy_ID. (This is also true
if libraw1394 runs at a host which contains multiple 1394 bus adapters.
The local ID 1023 is valid on each of these buses. The Linux host
itself is no IEEE 1394.1 bridge.)
</para>
<para>
Each node has a local address space with 48 bit wide addressing.
The whole bus can thus be seen as a linear 64 bit address space by
concatenating the node ID (most significant bits) and local
address (least significant bits). libraw1394 treats them separately in
function arguments to save the application some fiddling with the bits.
</para>
<para>
Unlike other buses there aren't many transactions or commands defined,
higher level commands are defined in terms of addresses accessed instead
of separate transaction types (comparable to memory mapped registers in
hardware). The 1394 transactions are:
<itemizedlist>
<listitem>
<para>read (quadlets and blocks)</para>
</listitem>
<listitem>
<para>write (quadlets and blocks)</para>
</listitem>
<listitem>
<para>lock (some atomic modifications)</para>
</listitem>
</itemizedlist>
There is also the isochronous transaction (the above three are called
asynchronous transactions), which is a broadcast stream with guaranteed
bandwidth. It doesn't contain any address but is distinguished by a 6
bit channel number.
</para>
<para>
The bus view is only logical, physically it consists of many
point-to-point connections between nodes with every node forwarding data
it receives to every other port which is capable of the speed the
transaction is sent at (thus a S200 node in the path between two S400
nodes would limit their communication speed to S200). It forms a tree
structure with all but one node having a parent and a number of
children. One node is the root node and has no parents.
</para>
</sect1>
<sect1>
<title>Bus Reset</title>
<para>
A bus reset occurs whenever the state of any node changes (including
addition and removal of nodes). At the beginning a root node is chosen,
then the tree identification determines for every node which port is
connected to a parent, child or nothing. Then the SelfID phase begins.
The root node sends a SelfID grant on its first port connected to a
child. If that is not a leaf node, it will itself forward the grant to
its first child. When a leaf node gets a grant, it will pick the lowest
physical ID not yet in use (starting with 0) and send out a SelfID packet
with its physical ID and more information, then acknowledge the SelfID
grant to its parent, which will send a grant to its next child until it
configured all its children, then pick a physical ID itself, send SelfID
packet and ack to parent.
</para>
<para>
After bus reset the used physical IDs are in a sequential range with no
holes starting from 0 up to the root node having the highest ID. This
also means that physical IDs can change for many or all nodes with the
insertion of a new node or moving the role of root to another node. In
libraw1394 all transactions are tagged automatically with a generation
number which is increased in every bus reset and transactions with an
obsolete generation will fail in order to avoid targetting the wrong
node. Nodes have to be identified in a different way than their
volatile physical IDs, namely by reading their globally unique ID (GUID)
contained in the configuration ROM.
</para>
</sect1>
<sect1>
<title>Transactions</title>
<para>
The packets transmitted on the bus are acknowledged by the receiving end
unless they are broadcast packets (broadcast writes and isochronous
packets). The acknowledge code contains an error code, which either
signifies error, success or packet pending. In the first two cases the
transaction completes, in the last a response packet will follow at a
later time from the targetted node to the source node (this is called a
split transaction). Only writes can succeed and complete in the ack
code, reads and locks require a response. Error and packet pending can
happen for every transaction. The response packets contain a response
code (rcode) which signifies success or type of error.
</para>
<para>
For read and write there are two different types, quadlet and block.
The quadlet types have all their payload (exactly one quadlet) in the
packet header, the block types have a variable length data block
appended to the header. Programs using libraw1394 don't have to care
about that, quadlet transactions are automatically used when the data
length is 4 bytes and block transactions otherwise.
</para>
<para>
The lock transaction has several extended transaction codes defined
which choose the atomic operation to perform, the most used being the
compare-and-swap (code 0x2). The transaction passes the data value and
(depending on the operation) the arg value to the target node and
returns the old value at the target address, but only when the
transaction does not have an error. All three values are of the same
size, either one quadlet or one octlet.
</para>
<para>
In the compare-and-swap case, the data value is written to the target
address if the old value is identical to the arg value. The old value
is returned in any case and can be used to find out whether the swap
succeeded by repeating the compare locally. Compare-and-swap
is useful for avoiding race conditions when accessing the same
address from multiple nodes. For example, isochronous resource
allocation is done using compare-and-swap, as described below. Since
the old value is always returned, it more efficient to do the first
attempt with the reset value of the target register as arg instead of
reading it first. Repeat with the returned old value as new arg value
if it didn't succeed.
</para>
</sect1>
<sect1>
<title>Bus Management</title>
<para>
There are three basic bus service nodes defined in IEEE 1394 (higher
level protocols may define more): cycle master, isochronous resource
manager and bus manager. These positions are contended for in and
shortly after the bus reset and may all be taken by a single node. A
node does not have to support being any of those but if it is bus
manager capable it also has to be iso manager capable, if it is iso
manager capable it also has to be cycle master capable.
</para>
<para>
The cycle master sends 8000 cycle start packets per second, which
initiate an iso cycle. Without that, no isochronous transmission is
possible. Only the root node is allowed to be cycle master, if it is
not capable then no iso transmissions can occur (and the iso or bus
manager have to select another node to become root and initiate a bus
reset).
</para>
<para>
The isochronous resource manager is the central point where channel and
bandwidth allocations are stored. A bit in the SelfID shows whether a
node is iso manager capable or not, the iso manager capable node with
the highest ID wins the position after a bus reset. Apart from
containing allocation registers, this one doesn't do much. Only if
there is no bus manager, it may determine a cycle master capable node to
become root and initiate a bus reset.
</para>
<para>
The bus manager has more responsibilities: power management (calculate
power provision and consumption on the bus and turn on disabled nodes if
enough power is available), bus optimization (calculate an effective gap
count, optimize the topology by selecting a better positioned node for
root) and some registers relevant to topology (topology map containing
the SelfIDs of the last reset and a speed map, which is obsoleted in
IEEE 1394a). The bus manager capable nodes contend for the role by
doing a lock transaction on the bus manager ID register in the iso
manager, the first to successfully complete the transaction wins the
role.
</para>
</sect1>
<sect1>
<title>Isochronous Transmissions</title>
<para>
Nodes can allocate a channel and bandwidth for isochronous transmissions
at the iso manager to broadcast timing critical data (e.g. multimedia
streams) on the bus. However these transmissions are unreliable, there
is no guarantee that every packet reaches the intended recipients (the
software and hardware involved also take iso packets a bit more
lightly). After a cycle start packet, the isochronous cycle begins and
every node can transmit iso packets, however only one packet per channel
is allowed. As soon as a gap of a certain length appears (i.e. no node
sends anymore), the iso cycle ends and the rest of the time until the
next cycle start is reserved for asynchronous packets.
</para>
<para>
The channel register on the iso manager consists of 64 bits, each of
which signifies one channel. A channel can be allocated by any node by
doing a compare-swap lock request with the new bitmask. Likewise the
bandwidth can be allocated by doing a lock request with the new value.
The bandwidth register contains the remaining time available for every
iso cycle. Since you allocate time, the maximum data you are allowed to
put into an iso packet depends on the speed you will send at.
</para>
<para>
On every bus reset, the resource registers are resetted to their initial
values (all channels free, all bandwidth minus some amount set aside for
asynchronous communication available), this has to happen since the
isochronous manager may have moved to another node. Isochronous
transmissions may continue with the old allocations for 1000ms. During
that time, the nodes have to reallocate their resources and no new
allocations are allowed to occur. Only after this period new
allocations may be done, this avoids nodes losing their allocations over
a bus reset.
</para>
<para>
libraw1394 does not provide special functions for allocating iso
resources nor does it clean up after programs when they exit. Protocols
exist that require the first node to use some resources to allocate it
and then leave it for the last node using it to deallocate it. This may
be different nodes, so automatic behaviour would be very undesirable in
these cases.
</para>
</sect1>
</chapter>
<chapter id="general">
<title>Data Structures and Program Flow</title>
<sect1>
<title>Overview</title>
<para>
The 1394 subsystem in Linux is divided into the classical
three layers, like most other interface subsystems in Linux.
The in-kernel subsystem consists of the ieee1394 core, which
provides basic services like handling of the 1394 protocol
(converting the abstract transactions into packets and back),
collecting information about bus and nodes and providing some
services to the bus that are required to be available for
standards conformant nodes (e.g. CSR registers). Below that
are the hardware drivers, which handle converting packets and
bus events to and from hardware accesses on specific 1394
chipsets.
</para>
<para>
Above the core are the highlevel drivers, which use the services
provided by the core to implement protocols for certain devices and act
as drivers to these. raw1394 is one such driver, however it is not
specialized to handle one kind of device but is designed to accept
commands from user space to do any transaction wanted (as far as
possible from current core design). Using raw1394, normal applications
can access 1394 nodes on the bus and it is not neccessary to write
kernel code just for that.
</para>
<para>
raw1394 communicates to user space like most device drivers do, through
device files in /dev. It uses a defined protocol on that device, but
applications don't have to and should not care about that. All of this
is taken care of by libraw1394, which provides a set of functions that
convert to and from raw1394 protocol packets and are a lot easier to
handle than that underlying protocol.
</para>
</sect1>
<sect1>
<title>Handles</title>
<para>
The handle presented to the application for using libraw1394 is the
raw1394handle_t, an opaque data structure (which means you don't need to
know its internals). The handle (and with it a connection to the kernel
side of raw1394) is obtained using
<function>raw1394_new_handle()</function>. Insufficient permissions to
access the kernel driver will result in failure of this function, among
other possibilities of failure.
</para>
<para>
While initializing the handle, a certain order of function calls have to
be obeyed or undefined results will occur. This order reflects the
various states of initialization to be done:
</para>
<para>
<orderedlist>
<listitem>
<para><function>raw1394_new_handle()</function></para>
</listitem>
<listitem>
<para><function>raw1394_get_port_info()</function></para>
</listitem>
<listitem>
<para><function>raw1394_set_port()</function></para>
</listitem>
</orderedlist>
</para>
</sect1>
<sect1>
<title>Ports</title>
<para>
A computer may have multiple 1394 buses connected by having multiple
1394 chips. Each of these is called a port, and the handle has to be
connected to one port before it can be used for anything. Even if no
nodes are connected to the chip in question, it forms a complete bus
(with just one node, itself).
</para>
<para>
A list of available ports together with some information about it (name
of the hardware, number of connected nodes) is available via
<function>raw1394_get_port_info()</function>, which is to be called
right after getting a fresh handle. The user should be presented with a
choice of available ports if there is more than one. It may be good
practice to do that even if there is only one port, since that may
result from a normally configured port just not being available, making
it confusing to be dropped right into the application attached to a port
without a choice and notion of anything going wrong.
</para>
<para>
The choice of port is then reported using
<function>raw1394_set_port()</function>. If this function fails and
<symbol>errno</symbol> is set to <symbol>ESTALE</symbol>, then
something has changed about the ports (port was added or removed)
between getting the port info and trying to set a port. It is
required that the current port list is fetched (presenting the user
with the choice again) and setting the port is retried with the new
data.
</para>
<para>
After a successful <function>raw1394_set_port()</function>, the get and
set port functions must not be used anymore on this handle. Undefined
results occur if you do so. To make up for this, all the other
functions are allowed now.
</para>
</sect1>
<sect1>
<title>The Event Loop</title>
<para>
All commands in libraw1394 are asynchronous, with some
synchronous wrapper functions for some types of transactions.
This means that there are two streams of data, one going into
raw1394 and one coming out. With this design you can send out
multiple transactions without having to wait for the response
before you can continue (sending out other transactions, for
example). The responses and other events (like bus resets and
received isochronous packets) are queued, and you can get them
with <function>raw1394_loop_iterate()</function> or
<function>raw1394_loop_iterate_timeout()</function> (which
always returns after a user-specified timeout if no
raw1394 event has occurred).
</para>
<para>
This forms an event loop you may already know from similar systems like
GUI toolkits. <function>raw1394_loop_iterate()</function> gets one
message from the event queue in raw1394, processes it with the
configured callback functions and returns the value returned by the
callback (so you can signal to the main loop from your callback; the
standard callbacks all return 0). It normally blocks when there are no
events and always processes only one event. If you are only receiving
broadcast events like isochronous packets you thus have to set up a loop
continuously calling the iterate function to get your callbacks called.
</para>
<para>
Often it is necessary to have multiple event loops and combine
them, e.g. if your application uses a GUI toolkit which also
has its own event loop. In that case you can use
<function>raw1394_get_fd()</function> to get the file
descriptor used for this handle by libraw1394. The fd can be
used to for <function>select()</function> or
<function>poll()</function> calls together with the other
loop's fd. (Most toolkits, like GTK and Qt, have special APIs
for integrating file descriptors into their own event loops).
</para>
<para>
If using <function>poll()</function>, you must test for
<symbol>POLLIN</symbol> and <symbol>POLLPRI</symbol>
events. If using <function>select()</function>, you must test
for both read and exception activity.
</para>
<para> If any of these conditions trigger, you should then call
<function>raw1394_loop_iterate()</function> to pick up the
event. <function>raw1394_loop_iterate()</function> is
guaranteed not to block when called immediately after select()
or poll() indicates activity. After the first call you
continue the main event loop. If more events wait, the
<function>select()</function>/<function>poll()</function> will
immediately return again.
</para>
<para>
You can also use the fd to set the <symbol>O_NONBLOCK</symbol> flag with
<function>fcntl()</function>. After that, the iterate function will not
block anymore but fail with <symbol>errno</symbol> set to
<symbol>EAGAIN</symbol> if no events wait. These are the only legal
uses for the fd returned by <function>raw1394_get_fd()</function>.
</para>
<para>
There are some functions which provide a synchronous wrapper for
transactions, note that these will call
<function>raw1394_loop_iterate()</function> continuously until their
transaction is completed, thus having implicit callback invocations
during their execution. The standard transaction functions have names
of the form <function>raw1394_start_xxx</function>, the synchronous
wrappers are called <function>raw1394_xxx</function>.
</para>
</sect1>
<sect1>
<title>Handlers</title>
<para>
There are a number of handlers which can be set using the appropriate
function as described in the function reference and which libraw1394
will call during a <function>raw1394_loop_iterate()</function>. These
are:
<itemizedlist>
<listitem>
<para>tag handler (called for completed commands)</para>
</listitem>
<listitem>
<para>bus reset handler (called when a bus reset happens)</para>
</listitem>
<listitem>
<para>iso handler (called when an iso packet is received)
</para>
</listitem>
<listitem>
<para>fcp handler (called when a FCP command or response is
received)</para>
</listitem>
</itemizedlist>
The bus reset handler is always called, the tag handler for every
command that completes, the iso handler and fcp handler are only called
when the application chooses to receive these packets. Handlers return
an integer value which is passed on by
<function>raw1394_loop_iterate()</function> (only one handler is called
per invocation), <constant>0</constant> is returned without a handler in
place.
</para>
<para>
The tag handler case is a bit special since the default handler is
actually doing something. Every command that you start can be given an
unsigned long tag which is passed untouched to the tag handler when the
event loop sees a completed command. The default handler expects this
value to be a pointer to a <structname>raw1394_reqhandle</structname>
structure, which contains a data pointer and its own callback function
pointer. The callback gets the untouched data pointer and error code as
arguments. If you want to use tags that are not
<structname>raw1394_reqhandle</structname> pointers you have to set up
your own tag handler.
</para>
</sect1>
<sect1>
<title>Generation Numbers</title>
<para>
libraw1394 and the kernel code use generation numbers to identify the
current bus configuration and increment those on every configuration
change. The most important generation number is stored per connected
1394 bus and incremented on every bus reset. There is another number
managed by raw1394 which identifies global changes (like a complete port
being added or removed), which is used for the
<function>raw1394_set_port()</function> function to make sure you don't
use stale port numbers. This is done transparently to you.
</para>
<para>
The bus generation number is more relevant for your work. Since nodes
can change IDs with every bus reset, it is very likely that you don't
want to send a packet you constructed with the old ID before you noticed
the bus reset. This does not apply to isochronous transmissions, since
they are broadcast and do not depend on bus configuration. Therefore
every packet is automatically tagged with the expected generation
number, and it will fail to send if that does not match the number
managed in the kernel for the port in question.
</para>
<para>
You get the current generation number through the bus reset handler. If
you don't set a custom bus reset handler, the default handler will
update the generation number automatically. If you set your own
handler, you can update the generation number to be used through
<function>raw1394_update_generation()</function> directly in the handler
or later.
</para>
</sect1>
<sect1>
<title>Error and Success Codes</title>
<para>
libraw1394 returns the ack/rcode pair in most transaction cases. The
rcode is undefined in cases where the ack code is not equal to
<symbol>ack_pending</symbol>. This is stored in a type
<type>raw1394_errcode_t</type>, from which the ack and rcode parts can
be extracted using two macros.
</para>
<para>
With the function <function>raw1394_errcode_to_errno()</function> it is
possible to convert this to an errno number that conveys roughly the
same meaning. Many developers will find that easier to handle. This is
done automatically for the synchronous read/write/lock wrapper
functions, i.e. they return 0 for success and a negative value for
failure, in which case they also set the <symbol>errno</symbol> variable
to the appropriate code. The raw ack/rcode pair can then still be
retrieved using <function>raw1394_get_errcode()</function>.
</para>
</sect1>
</chapter>
<chapter id="isochronous">
<title>Isochronous Transmission and Reception</title>
<sect1>
<title>Overview</title>
<para>
Isochronous operations involve sending or receiving a constant
stream of packets at a fixed rate of 8KHz. Unlike raw1394's
asynchronous API, where you "push" packets to raw1394
functions at your leisure, the isochronous API is based around
a "pull" model. During isochronous transmission or reception,
raw1394 informs your application when a packet must be sent or
received. You must fulfill these requests in a timely manner
to avoid breaking the constant stream of isochronous packets.
</para>
<para>
A raw1394 handle may be associated with one isochronous
stream, either transmitting or receiving (but not both at the
same time). To transmit or receive more than one stream
simultaneously, you must create more than one raw1394 handle.
</para>
</sect1>
<sect1>
<title>Initialization</title>
<para>
When a raw1394 handle is first created, no isochronous
stream is assocated with it. To begin isochronous
operations, call either
<function>raw1394_iso_xmit_init()</function> (transmission) or
<function>raw1394_iso_recv_init()</function>
(reception). The parameters to these functions are as follows:
</para>
<para>
<symbol>handler</symbol> is your function for queueing
packets to be sent (transmission) or processing received
packets (reception).
</para>
<para>
<symbol>buf_packets</symbol> is the number of packets that
will be buffered at the kernel level. A larger packet buffer
will be more forgiving of IRQ and application latency,
however it will consume more kernel memory. For most
applications, it is sufficient to buffer 2000-16000 packets
(0.25 seconds to 2.0 seconds maximum latency).
</para>
<para>
<symbol>max_packet_size</symbol> is the size, in bytes, of
the largest isochronous packet you intend to handle. This
size does not include the isochronous header but it does
include the CIP header specified by many isochronous
protocols.
</para>
<para>
<symbol>channel</symbol> is the isochronous channel on which
you wish to receive or transmit. (currently there is no
facility for multi-channel transmission or reception).
</para>
<para>
<symbol>speed</symbol> is the isochronous speed at which you
wish to operate. Possible values are
<symbol>RAW1394_ISO_SPEED_100</symbol>,
<symbol>RAW1394_ISO_SPEED_200</symbol>, and
<symbol>RAW1394_ISO_SPEED_400</symbol>.
</para>
<para>
<symbol>irq_interval</symbol> is the maximum latency of the
kernel buffer, in packets. (To avoid excessive IRQ rates, the
low-level drivers only trigger an interrupt every
irq_interval packets). Pass -1 to receive a default value
that should be suitable for most applications.
</para>
<para>
<symbol>mode</symbol> for <function>raw1394_iso_recv_init()</function>
sets whether to use packet-per-buffer or buffer-fill receive mode.
Possible values are <symbol>RAW1394_DMA_DEFAULT</symbol> (bufferfill
on ohci1394), <symbol>RAW1394_DMA_BUFFERFILL</symbol>, and
<symbol>RAW1394_DMA_PACKET_PER_BUFFER</symbol>.
</para>
<para>
If <function>raw1394_iso_xmit/recv_init()</function> retuns
successfully, then you may start isochronous operations. You
may not call
<function>raw1394_iso_xmit/recv_init()</function> again on
the same handle without first shutting down the isochronous
operation with <function>raw1394_iso_shutdown()</function>.
</para>
<para>
Note that <function>raw1394_iso_xmit_init()</function> and
<function>raw1394_iso_recv_init()</function> involve
potentially time-consuming operations like allocating kernel
and device resources. If you intend to transmit or receive
several isochronous streams simultaneously, it is advisable
to initialize all streams before starting any packet
transmission or reception.
</para>
</sect1>
<sect1>
<title>Stopping and Starting</title>
<para>
Once the isochronous operation has been initialized, you may
start and stop packet transmission with
<function>raw1394_iso_xmit/recv_start()</function> and
<function>raw1394_iso_stop()</function>. It is legal to call
these as many times as you want, and it is permissible to
start an already-started stream or stop an already-stopped
stream. Packets that have been queued for transmission or
reception will remain queued when the operation is stopped.
</para>
<para>
<function>raw1394_iso_xmit/recv_start()</function> allow you
to specify on which isochronous cycle number to start
transmitting or receiving packets. Pass -1 to start
immediately. This parameter is ignored if isochronous
transmission or reception is already in progress.
</para>
<para>
<function>raw1394_iso_xmit_start()</function> has an
additional parameter, <symbol>prebuffer_packets</symbol>,
which specifies how many packets to queue up before starting
transmission. Possible values range from zero (start
transmission immediately after the first packet is queued)
up to the total number of packets in the buffer.
</para>
<para>
Once the isochronous operation has started, you must
repeatedly call <function>raw1394_loop_iterate()</function>
as usual to drive packet processing.
</para>
</sect1>
<sect1>
<title>Receiving Packets</title>
<para>
Raw1394 maintains a fixed-size ringbuffer of packets in
kernel memory. The buffer is filled by the low-level driver
as it receives packets from the bus. It is your
application's job to process each packet, after which the
buffer space it occupied can be re-used for future packets.
</para>
<para>
The isochronous receive handler you provided will be called
from <function>raw1394_loop_iterate()</function> after each
packet is received. Your handler is passed a pointer to the
first byte of the packet's data payload, plus the packet's
length in bytes (not counting the isochronous header), the
cycle number at which it was received, the channel on which
it was received, and the "tag" and "sy" fields from the
isochronous header. Note that the packet is at this point
still in the kernel's receive buffer, so the data pointer is
only valid until the receive handler returns. You must make
a copy of the packet's data if you want to keep it.
</para>
<para>
The receive handler is also passed a "packet(s) dropped"
flag. If this flag is nonzero, it means that one or more
incoming packets have been dropped since the last call to
your handler (usually this is because the kernel buffer has
completely filled up with packets or a bus reset has
occurred).
</para>
</sect1>
<sect1>
<title>Transmitting Packets</title>
<para>
Similar to reception, raw1394 maintains a fixed-size
ringbuffer of packets in kernel memory. The buffer is filled
by your application as it queues packets to be sent. The
buffer is drained by the hardware driver as it transmits
packets on the 1394 bus.
</para>
<para>
The isochronous transmit handler you provided will be called
from <function>raw1394_loop_iterate()</function> whenever
there is space in the buffer to queue another packet. The
handler is passed a pointer to the first byte of the buffer
space for the packet's data payload, pointers to words
containing the data length in bytes (not counting the
isochronous header), "tag" and "sy" fields, and the
isochronous cycle number at which this packet will be
transmitted. The handler must write the packet's data
payload into the supplied buffer space, and set the values
pointed to by "len", "tag", and "sy" to the appropriate
values. The handler is permitted to write any number of data
bytes, up and including to the value of
<symbol>max_packet_size</symbol> passed to
<function>raw1394_iso_xmit_init()</function>.
</para>
<para>
Note: If you passed -1 as the starting cycle to
<function>raw1394_iso_xmit_init()</function>, the cycle
number provided to your handler will be incorrect until after
one buffer's worth of packets have been transmitted.
</para>
<para>
The transmit handler is also passed a "packet(s) dropped"
flag. If this flag is nonzero, it means that one or more
outgoing packets have been dropped since the last call to
your handler (usually this is because the kernel buffer has
gone completely empty or a bus reset has occurred).
</para>
</sect1>
<sect1>
<title>Shutting down</title>
<para>
When the isochronous operation has finished, call
<function>raw1394_iso_shutdown()</function> to release all
associated resources. If you don't call this function
explicitly, it will be called automatically when the raw1394
handle is destroyed.
</para>
</sect1>
</chapter>
<chapter id="functions">
<title>Function Reference</title>
<refentry id="API-raw1394-iso-xmit-init">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_iso_xmit_init</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_iso_xmit_init</refname>
<refpurpose>
initialize isochronous transmission
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_iso_xmit_init </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>raw1394_iso_xmit_handler_t <parameter>handler</parameter></paramdef>
<paramdef>unsigned int <parameter>buf_packets</parameter></paramdef>
<paramdef>unsigned int <parameter>max_packet_size</parameter></paramdef>
<paramdef>unsigned char <parameter>channel</parameter></paramdef>
<paramdef>enum raw1394_iso_speed <parameter>speed</parameter></paramdef>
<paramdef>int <parameter>irq_interval</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>handler</parameter></term>
<listitem>
<para>
handler function for queueing packets
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>buf_packets</parameter></term>
<listitem>
<para>
number of isochronous packets to buffer
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>max_packet_size</parameter></term>
<listitem>
<para>
largest packet you need to handle, in bytes
(not including the isochronous header)
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>channel</parameter></term>
<listitem>
<para>
isochronous channel on which to transmit
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>speed</parameter></term>
<listitem>
<para>
speed at which to transmit
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>irq_interval</parameter></term>
<listitem>
<para>
maximum latency of wake-ups, in packets (-1 if you don't care)
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Allocates all user and kernel resources necessary for isochronous transmission.
Channel and bandwidth allocation at the IRM is not performed.
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
0 on success or -1 on failure (sets errno)
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-iso-recv-init">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_iso_recv_init</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_iso_recv_init</refname>
<refpurpose>
initialize isochronous reception
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_iso_recv_init </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>raw1394_iso_recv_handler_t <parameter>handler</parameter></paramdef>
<paramdef>unsigned int <parameter>buf_packets</parameter></paramdef>
<paramdef>unsigned int <parameter>max_packet_size</parameter></paramdef>
<paramdef>unsigned char <parameter>channel</parameter></paramdef>
<paramdef>enum raw1394_iso_dma_recv_mode <parameter>mode</parameter></paramdef>
<paramdef>int <parameter>irq_interval</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>handler</parameter></term>
<listitem>
<para>
handler function for receiving packets
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>buf_packets</parameter></term>
<listitem>
<para>
number of isochronous packets to buffer
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>max_packet_size</parameter></term>
<listitem>
<para>
largest packet you need to handle, in bytes (not including
the isochronous header)
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>channel</parameter></term>
<listitem>
<para>
isochronous channel to receive
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>mode</parameter></term>
<listitem>
<para>
bufferfill or packet per buffer mode
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>irq_interval</parameter></term>
<listitem>
<para>
maximum latency of wake-ups, in packets
(-1 if you don't care)
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Allocates all user and kernel resources necessary for isochronous reception.
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
0 on success or -1 on failure (sets errno)
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-iso-multichannel-recv-init">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_iso_multichannel_recv_init</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_iso_multichannel_recv_init</refname>
<refpurpose>
initialize multi-channel iso reception
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_iso_multichannel_recv_init </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>raw1394_iso_recv_handler_t <parameter>handler</parameter></paramdef>
<paramdef>unsigned int <parameter>buf_packets</parameter></paramdef>
<paramdef>unsigned int <parameter>max_packet_size</parameter></paramdef>
<paramdef>int <parameter>irq_interval</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>handler</parameter></term>
<listitem>
<para>
handler function for receiving packets
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>buf_packets</parameter></term>
<listitem>
<para>
number of isochronous packets to buffer
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>max_packet_size</parameter></term>
<listitem>
<para>
largest packet you need to handle, in bytes (not including
the isochronous header)
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>irq_interval</parameter></term>
<listitem>
<para>
maximum latency of wake-ups, in packets (-1 if you don't care)
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Allocates all user and kernel resources necessary for isochronous reception.
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
0 on success or -1 on failure (sets errno)
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-iso-recv-listen-channel">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_iso_recv_listen_channel</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_iso_recv_listen_channel</refname>
<refpurpose>
listen to a specific channel in multi-channel mode
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_iso_recv_listen_channel </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>unsigned char <parameter>channel</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>channel</parameter></term>
<listitem>
<para>
the channel to start listening
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
listen/unlisten on a specific channel (multi-channel mode ONLY)
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
0 on success or -1 on failure (sets errno)
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-iso-recv-unlisten-channel">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_iso_recv_unlisten_channel</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_iso_recv_unlisten_channel</refname>
<refpurpose>
stop listening to a specific channel in multi-channel mode
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_iso_recv_unlisten_channel </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>unsigned char <parameter>channel</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>channel</parameter></term>
<listitem>
<para>
the channel to stop listening to
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
0 on success or -1 on failure (sets errno)
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-iso-recv-set-channel-mask">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_iso_recv_set_channel_mask</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_iso_recv_set_channel_mask</refname>
<refpurpose>
listen or unlisten to a whole bunch of channels at once
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_iso_recv_set_channel_mask </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>u_int64_t <parameter>mask</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>mask</parameter></term>
<listitem>
<para>
64-bit mask of channels, 1 means listen, 0 means unlisten,
channel 0 is LSB, channel 63 is MSB
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
for multi-channel reception mode only
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
0 on success, -1 on failure (sets errno)
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-iso-xmit-start">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_iso_xmit_start</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_iso_xmit_start</refname>
<refpurpose>
begin isochronous transmission
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_iso_xmit_start </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>int <parameter>start_on_cycle</parameter></paramdef>
<paramdef>int <parameter>prebuffer_packets</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>start_on_cycle</parameter></term>
<listitem>
<para>
isochronous cycle number on which to start
(-1 if you don't care)
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>prebuffer_packets</parameter></term>
<listitem>
<para>
number of packets to queue up before starting transmission
(-1 if you don't care)
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
0 on success or -1 on failure (sets errno)
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-iso-recv-start">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_iso_recv_start</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_iso_recv_start</refname>
<refpurpose>
begin isochronous reception
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_iso_recv_start </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>int <parameter>start_on_cycle</parameter></paramdef>
<paramdef>int <parameter>tag_mask</parameter></paramdef>
<paramdef>int <parameter>sync</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>start_on_cycle</parameter></term>
<listitem>
<para>
isochronous cycle number on which to start
(-1 if you don't care)
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>tag_mask</parameter></term>
<listitem>
<para>
mask of tag fields to match (-1 to receive all packets)
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>sync</parameter></term>
<listitem>
<para>
not used, reserved for future implementation
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
0 on success or -1 on failure (sets errno)
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-iso-xmit-write">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_iso_xmit_write</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_iso_xmit_write</refname>
<refpurpose>
alternative blocking-write API for ISO transmission
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_iso_xmit_write </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>unsigned char * <parameter>data</parameter></paramdef>
<paramdef>unsigned int <parameter>len</parameter></paramdef>
<paramdef>unsigned char <parameter>tag</parameter></paramdef>
<paramdef>unsigned char <parameter>sy</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>data</parameter></term>
<listitem>
<para>
pointer to packet data buffer
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>len</parameter></term>
<listitem>
<para>
length of packet, in bytes
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>tag</parameter></term>
<listitem>
<para>
tag field
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>sy</parameter></term>
<listitem>
<para>
sync field
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
<function>write</function> style API - do NOT use this if you have set an xmit_handler
if buffer is full, waits for more space UNLESS the file descriptor is
set to non-blocking, in which case <function>xmit_write</function> will return -1 with
errno = EAGAIN
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
0 on success or -1 on failure (sets errno)
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-iso-xmit-sync">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_iso_xmit_sync</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_iso_xmit_sync</refname>
<refpurpose>
wait until all queued packets have been sent
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_iso_xmit_sync </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
0 on success or -1 on failure (sets errno)
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-iso-recv-flush">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_iso_recv_flush</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_iso_recv_flush</refname>
<refpurpose>
flush all already received iso packets from kernel into user space
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_iso_recv_flush </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
If you specified an irq_interval &gt; 1 in
iso_recv_init, you won't be notified for every single iso packet, but
for groups of them. Now e.g. if irq_interval is 100, and you were just
notified about iso packets and after them only 20 more packets arrived,
no notification will be generated (20 &lt; 100). In the case that you know
that there should be more packets at this moment, you can call this
function and all iso packets which are already received by the kernel
will be flushed out to user space.
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
0 on success or -1 on failure (sets errno)
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-iso-stop">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_iso_stop</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_iso_stop</refname>
<refpurpose>
halt isochronous transmission or reception
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>raw1394_iso_stop </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>
<refentry id="API-raw1394-iso-shutdown">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_iso_shutdown</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_iso_shutdown</refname>
<refpurpose>
clean up and deallocate all resources for isochronous transmission or reception
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>raw1394_iso_shutdown </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>
<refentry id="API-raw1394-read-cycle-timer">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_read_cycle_timer</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_read_cycle_timer</refname>
<refpurpose>
get the current value of the cycle timer
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_read_cycle_timer </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>u_int32_t * <parameter>cycle_timer</parameter></paramdef>
<paramdef>u_int64_t * <parameter>local_time</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>cycle_timer</parameter></term>
<listitem>
<para>
buffer for Isochronous Cycle Timer
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>local_time</parameter></term>
<listitem>
<para>
buffer for local system time in microseconds since Epoch
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Simultaneously reads the cycle timer register together with the system clock.
</para><para>
Format of <parameter>cycle_timer</parameter>, from MSB to LSB: 7 bits cycleSeconds (seconds, or
number of cycleCount rollovers), 13 bits cycleCount (isochronous cycles, or
cycleOffset rollovers), 12 bits cycleOffset (24.576 MHz clock ticks, not
provided on some hardware). The union of cycleSeconds and cycleCount is the
current cycle number. The nominal duration of a cycle is 125 microseconds.
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
the error code of the ioctl, or 0 if successful.
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-get-errcode">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_get_errcode</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_get_errcode</refname>
<refpurpose>
return error code of async transaction
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>raw1394_errcode_t <function>raw1394_get_errcode </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Some macros are available to extract information from the error code,
<function>raw1394_errcode_to_errno</function> can be used to convert it to an errno number of
roughly the same meaning.
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
the error code of the last <function>raw1394_read</function>, <function>raw1394_write</function>,
<function>raw1394_lock</function>. The error code is either an internal
error (i.e. not a bus error) or a combination of acknowledge code and
response code, as appropriate.
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-errcode-to-errno">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_errcode_to_errno</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_errcode_to_errno</refname>
<refpurpose>
convert libraw1394 errcode to errno
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_errcode_to_errno </function></funcdef>
<paramdef>raw1394_errcode_t <parameter>errcode</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>errcode</parameter></term>
<listitem>
<para>
the error code to convert
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
The error code as retrieved by <function>raw1394_get_errcode</function> is converted into a
roughly equivalent errno number and returned. <constant>0xdead</constant> is returned for an
illegal errcode.
</para><para>
It is intended to be used to decide what to do (retry, give up, report error)
for those programs that aren't interested in details, since these get lost in
the conversion. However the returned errnos are equivalent in source code
meaning only, the associated text of e.g. <function>perror</function> is not necessarily
meaningful.
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
<constant>EAGAIN</constant> (retrying might succeed, also generation number
mismatch), <constant>EREMOTEIO</constant> (other node had internal problems), <constant>EPERM</constant> (operation
not allowed on this address, e.g. write on read-only location), <constant>EINVAL</constant>
(invalid argument) and <constant>EFAULT</constant> (invalid pointer).
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-new-handle">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_new_handle</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_new_handle</refname>
<refpurpose>
create new handle
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>raw1394handle_t <function>raw1394_new_handle </function></funcdef>
<paramdef> <parameter>void</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>void</parameter></term>
<listitem>
<para>
no arguments
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
</para><para>
Creates and returns a new handle which can (after being set up) control one
port. It is not allowed to use the same handle in multiple threads or forked
processes. It is allowed to create and use multiple handles, however. Use
one handle per thread which needs it in the multithreaded case.
</para><para>
The default device node is /dev/raw1394, but one can override the default
by setting environment variable RAW1394DEV. However, if RAW1394DEV points to
a non-existant or invalid device node, then it also attempts to open the
default device node.
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
the created handle or <constant>NULL</constant> when initialization fails. In the latter
case errno either contains some OS specific error code or EPROTO if
libraw1394 and raw1394 don't support each other's protocol versions.
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-destroy-handle">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_destroy_handle</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_destroy_handle</refname>
<refpurpose>
deallocate handle
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>raw1394_destroy_handle </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
handle to deallocate
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Closes connection with raw1394 on this handle and deallocates everything
associated with it. It is safe to pass <constant>NULL</constant> as handle, nothing is done in
this case.
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-new-handle-on-port">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_new_handle_on_port</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_new_handle_on_port</refname>
<refpurpose>
create a new handle and bind it to a port
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>raw1394handle_t <function>raw1394_new_handle_on_port </function></funcdef>
<paramdef>int <parameter>port</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>port</parameter></term>
<listitem>
<para>
port to connect to (same as argument to <function>raw1394_set_port</function>)
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Same as <function>raw1394_new_handle</function>, but also binds the handle to the
specified 1394 port. Equivalent to <function>raw1394_new_handle</function> followed by
<function>raw1394_get_port_info</function> and <function>raw1394_set_port</function>. Useful for
command-line programs that already know what port they want. If
<function>raw1394_set_port</function> returns ESTALE, retries automatically.
</para><para>
The default device node is /dev/raw1394, but one can override the default
by setting environment variable RAW1394DEV. However, if RAW1394DEV points to
a non-existant or invalid device node, then it also attempts to open the
default device node.
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
the new handle on success or NULL on failure
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-busreset-notify">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_busreset_notify</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_busreset_notify</refname>
<refpurpose>
Switch off/on busreset-notification for handle
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_busreset_notify </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>int <parameter>off_on_switch</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>off_on_switch</parameter></term>
<listitem>
<para>
RAW1394_NOTIFY_OFF or RAW1394_NOTIFY_ON
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
0 on success or -1 on failure (sets errno)
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-get-fd">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_get_fd</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_get_fd</refname>
<refpurpose>
get the communication file descriptor
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_get_fd </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
This can be used for <function>select</function>/<function>poll</function> calls if you wait on other fds or can be
integrated into another event loop (e.g. from a GUI application framework).
It can also be used to set/remove the O_NONBLOCK flag using <function>fcntl</function> to modify
the blocking behaviour in <function>raw1394_loop_iterate</function>. It must not be used for
anything else.
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
the fd used for communication with the raw1394 kernel module or -1
on failure (sets errno).
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-set-userdata">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_set_userdata</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_set_userdata</refname>
<refpurpose>
associate user data with a handle
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>raw1394_set_userdata </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>void * <parameter>data</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>data</parameter></term>
<listitem>
<para>
user data (pointer)
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Allows to associate one void pointer with a handle. libraw1394 does not care
about the data, it just stores it in the handle allowing it to be retrieved
at any time with <function>raw1394_get_userdata</function>. This can be useful when multiple
handles are used, so that callbacks can identify the handle.
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-get-userdata">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_get_userdata</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_get_userdata</refname>
<refpurpose>
retrieve user data from handle
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void * <function>raw1394_get_userdata </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
the user data pointer associated with the handle using
<function>raw1394_set_userdata</function>.
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-get-local-id">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_get_local_id</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_get_local_id</refname>
<refpurpose>
get node ID of the current port
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>nodeid_t <function>raw1394_get_local_id </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
the node ID of the local node connected to which the handle is
connected. This value can change with every bus reset.
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-get-irm-id">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_get_irm_id</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_get_irm_id</refname>
<refpurpose>
get node ID of isochronous resource manager
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>nodeid_t <function>raw1394_get_irm_id </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
the node ID of the isochronous resource manager of the bus the handle
is connected to. This value may change with every bus reset.
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-get-nodecount">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_get_nodecount</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_get_nodecount</refname>
<refpurpose>
get number of nodes on the bus
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_get_nodecount </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Since the root node always has
the highest node ID, this number can be used to determine that ID (it's
LOCAL_BUS|(count-1)).
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
the number of nodes on the bus to which the handle is connected.
This value can change with every bus reset.
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-get-port-info">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_get_port_info</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_get_port_info</refname>
<refpurpose>
get information about available ports
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_get_port_info </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>struct raw1394_portinfo * <parameter>pinf</parameter></paramdef>
<paramdef>int <parameter>maxports</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>pinf</parameter></term>
<listitem>
<para>
pointer to an array of struct raw1394_portinfo
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>maxports</parameter></term>
<listitem>
<para>
number of elements in <parameter>pinf</parameter>
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Before you can set which port to use, you have to use this function to find
out which ports exist.
</para><para>
If your program is interactive, you should present the user with this list to
let them decide which port to use if there is more than one. A
non-interactive program (and probably interactive ones, too) should provide a
command line option to choose the port. If <parameter>maxports</parameter> is <constant>0</constant>, <parameter>pinf</parameter> can be
<constant>NULL</constant>, too.
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
the number of ports and writes information about them into <parameter>pinf</parameter>, but
not into more than <parameter>maxports</parameter> elements.
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-set-port">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_set_port</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_set_port</refname>
<refpurpose>
choose port for handle
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_set_port </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>int <parameter>port</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>port</parameter></term>
<listitem>
<para>
port to connect to (corresponds to index of struct raw1394_portinfo)
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
This function connects the handle to the port given (as queried with
<function>raw1394_get_port_info</function>). If successful, <function>raw1394_get_port_info</function> and
<function>raw1394_set_port</function> are not allowed to be called afterwards on this handle.
To make up for this, all the other functions (those handling asynchronous and
isochronous transmissions) can now be called.
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
<constant>0</constant> for success or -1 for failure with errno set appropriately. A
possible failure mode is with errno = <constant>ESTALE</constant>, in this case the configuration
has changed since the call to <function>raw1394_get_port_info</function> and it has to be called
again to update your view of the available ports.
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-reset-bus">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_reset_bus</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_reset_bus</refname>
<refpurpose>
initiate bus reset
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_reset_bus </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
This function initiates a bus reset on the connected port. Usually this is
not necessary and should be avoided, this function is here for low level bus
control and debugging.
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
<constant>0</constant> for success or -1 for failure with errno set appropriately
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-reset-bus-new">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_reset_bus_new</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_reset_bus_new</refname>
<refpurpose>
Reset the connected bus (with certain type).
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_reset_bus_new </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>int <parameter>type</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>type</parameter></term>
<listitem>
<para>
RAW1394_SHORT_RESET or RAW1394_LONG_RESET
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
<constant>0</constant> for success or -1 for failure
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-loop-iterate">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_loop_iterate</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_loop_iterate</refname>
<refpurpose>
get and process one event message
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>raw1394_loop_iterate </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Get one new message through handle and process it with the registered message
handler. Note that some other library functions may call this function
multiple times to wait for their completion, some handler return values may
get lost if you use these.
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
<constant>-1</constant> for an error or the return value of
the handler which got executed. The default handlers always return zero.
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-set-bus-reset-handler">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_set_bus_reset_handler</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_set_bus_reset_handler</refname>
<refpurpose>
set bus reset handler
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>bus_reset_handler_t <function>raw1394_set_bus_reset_handler </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>bus_reset_handler_t <parameter>new_h</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>new_h</parameter></term>
<listitem>
<para>
pointer to new handler
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Sets the handler to be called on every bus reset to <parameter>new_h</parameter>.
The default handler just calls <function>raw1394_update_generation</function>.
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
the old handler or NULL on failure (sets errno)
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-get-generation">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_get_generation</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_get_generation</refname>
<refpurpose>
get generation number of handle
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>unsigned int <function>raw1394_get_generation </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
The generation number is incremented on every bus reset, and every transaction
started by raw1394 is tagged with the stored generation number. If these
don't match, the transaction will abort with an error.
The generation number of the handle is not automatically updated,
<function>raw1394_update_generation</function> has to be used for this.
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
the generation number associated with the handle or UINT_MAX on
failure.
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-update-generation">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_update_generation</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_update_generation</refname>
<refpurpose>
set generation number of handle
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>raw1394_update_generation </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>unsigned int <parameter>generation</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>generation</parameter></term>
<listitem>
<para>
new generation number
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
This function sets the generation number of the handle to <parameter>gen</parameter>. All requests
that apply to a single node ID are tagged with this number and abort with an
error if that is different from the generation number kept in the kernel.
This avoids acting on the wrong node which may have changed its ID in a bus
reset.
</para><para>
You should call this within your bus reset handler with an incremented value.
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-set-tag-handler">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_set_tag_handler</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_set_tag_handler</refname>
<refpurpose>
set request completion handler
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>tag_handler_t <function>raw1394_set_tag_handler </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>tag_handler_t <parameter>new_h</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>new_h</parameter></term>
<listitem>
<para>
pointer to new handler
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Sets the handler to be called whenever a request completes to <parameter>new_h</parameter>.
The default handler interprets the tag as a pointer
to a <structname>struct raw1394_reqhandle</structname> and calls the callback in there.
</para><para>
Care must be taken when replacing the tag handler and calling the synchronous
versions of the transaction functions (i.e. <function>raw1394_read</function>, <function>raw1394_write</function>,
<function>raw1394_lock</function>) since these do pass pointers to <structname>struct
raw1394_reqhandle</structname> as the tag and expect the callback to be invoked.
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
the old handler or NULL on failure (sets errno)
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-set-arm-tag-handler">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_set_arm_tag_handler</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_set_arm_tag_handler</refname>
<refpurpose>
set the async request handler
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>arm_tag_handler_t <function>raw1394_set_arm_tag_handler </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>arm_tag_handler_t <parameter>new_h</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>new_h</parameter></term>
<listitem>
<para>
pointer to new handler
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Set the handler that will be called when an async read/write/lock arm_request
arrived. The default action is to call the arm_callback in the
raw1394_arm_reqhandle pointed to by arm_tag.
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
old handler or NULL on failure (sets errno)
</para>
</refsect1>
</refentry>
<refentry id="API-raw1394-set-fcp-handler">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>raw1394_set_fcp_handler</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>raw1394_set_fcp_handler</refname>
<refpurpose>
set FCP handler
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>fcp_handler_t <function>raw1394_set_fcp_handler </function></funcdef>
<paramdef>raw1394handle_t <parameter>handle</parameter></paramdef>
<paramdef>fcp_handler_t <parameter>new_h</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>handle</parameter></term>
<listitem>
<para>
libraw1394 handle
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>new_h</parameter></term>
<listitem>
<para>
pointer to new handler
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Function Control Protocol is defined in IEC 61883-1.
</para><para>
Sets the handler to be called when either FCP command or FCP response
registers get written to <parameter>new_h</parameter>. The default handler does nothing.
In order to actually get FCP events, you have to enable it with
<function>raw1394_start_fcp_listen</function> and can stop it with <function>raw1394_stop_fcp_listen</function>.
</para>
</refsect1>
<refsect1>
<title>Returns</title>
<para>
the old handler or NULL on failure (sets errno)
</para>
</refsect1>
</refentry>
<refentry id="API-int">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>int</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>int</refname>
<refpurpose>
This is the general request handler
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>typedef <function>int </function></funcdef>
<paramdef> * <parameter>req_callback_t</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>req_callback_t</parameter></term>
<listitem>
<para>
This is the general request handler
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
It is used by the default tag handler
when a request completes, it calls the callback and passes it the data
pointer and the error code of the request.
</para>
</refsect1>
</refentry>
<refentry id="API-int">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>August 2009</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>int</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">unknown kernel version</refmiscinfo>
</refmeta>
<refnamediv>
<refname>int</refname>
<refpurpose>
This is the general arm-request handle
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>typedef <function>int </function></funcdef>
<paramdef> * <parameter>arm_req_callback_t</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>arm_req_callback_t</parameter></term>
<listitem>
<para>
This is the general arm-request handle
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
(arm = address range mapping)
It is used by the default arm-tag handler when a request has been
received, it calls the arm_callback.
</para>
</refsect1>
</refentry>