Because we might be in interrupt context, replace del_timer_sync() with
del_timer().  If the timer is already running, we know that it will
clean up the transaction, so we do not need to do any further processing
in the normal transaction handler.

Many thanks to Yong Zhang for diagnosing this.
Reported-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The incoming request hander fwnet_receive_packet() expects subsequent
datagram handling code to return non-zero on errors.  However, almost
none of the failure paths did so.  Fix them all.

(This error reporting is used to send and RCODE_CONFLICT_ERROR to the
sender node in such failure cases.  Two modes of failure exist:  Out of
memory, or firewire-net is unaware of any peer node to which a fragment
or an ARP packet belongs.  However, it is unclear whether a sender can
actually make use of such information.  A Linux peer apparently can't.
Maybe it should all be simplified to void functions.)
Reported-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Fix I/O stalls with some 4-bay RAID enclosures which are based on
OXUF936QSE:
  - Onnto dataTale RSM4QO, old firmware (not anymore with current
    firmware),
  - inXtron Hydra Super-S LCM, old as well as current firmware
when used in RAID-5 mode, perhaps also in other RAID modes.

The stalls happen during heavy or moderate disk traffic in periods that
are a multiple of 5 minutes, roughly twice per hour.  They are caused
by the target responding too late to an ORB_Pointer register write:
The target responds after Split_Timeout, hence firewire-core cancels
the transaction, and firewire-sbp2 fails the SCSI request.  The SCSI
core retries the request, that fails again (and again), hence SCSI core
calls firewire-sbp2's abort handler (and even the Management_Agent
register write in the abort handler has the transaction timeout
problem).

During all that, the process which issued the I/O is stalled in I/O
wait state.

Meanwhile, the target actually acts on the first failed SCSI request:
It responds to the ORB_Pointer write later (seen in the kernel log as
"firewire_core: Unsolicited response") and also finishes the SCSI
request with proper status (seen in the kernel log as "firewire_sbp2:
status write for unknown orb").

So let's just ignore RCODE_CANCELLED in the transaction callback and
wait for the target to complete the ORB nevertheless.  This requires
a small modification is sbp2_cancel_orbs(); it now needs to call
orb->callback() regardless whether fw_cancel_transaction() found the
transaction unfinished or finished.

A different solution is to increase Split_Timeout on the local node.
(Tested: 2000ms timeout; maybe 1000ms or something like that works too.
200ms is insufficient.  Standard is 100ms.)  However, I rather not do
this because any software on any node could change the Split_Timeout to
something unsuitable.  Or such a large Split_Timeout may be undesirable
for other purposes.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

When an ORB was canceled (Command ORB i.e. SCSI request timed out, or
Management ORB timed out), or there was a send error in the initial
transaction, we missed to drop one of the ORB's references and thus
leaked memory.

Background:
In total, we hold 3 references to each Operation Request Block:
  - 1 during sbp2_scsi_queuecommand() or sbp2_send_management_orb()
    respectively,
  - 1 for the duration of the write transaction to the ORB_Pointer or
    Management_Agent register of the target,
  - 1 for as long as the ORB stays within the lu->orb_list, until
    the ORB is unlinked from the list and the orb->callback was
    executed.

The latter one of these 3 references is finished
  - normally by sbp2_status_write() when the target wrote status
    for a pending ORB,
  - or by sbp2_cancel_orbs() in case of an ORB time-out,
  - or by complete_transaction() in case of a send error.
Of them, the latter two lacked the kref_put.

Add the missing kref_put()s.  Add comments to the gets and puts of
references for transaction callbacks and ORB callbacks so that it is
easier to see what is supposed to happen.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

There is an at least theoretic race condition in which .start_iso etc.
could still be called between when the dummy driver is bound to the card
and when the children devices are being shut down.  Add dummy_start_iso
and friends.

On the other hand, .enable, .set_config_rom, .read_csr, write_csr do not
need to be implemented by the dummy driver, as commented.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

This adds the DMA context programming and userspace ABI for multichannel
reception, i.e. for listening on multiple channel numbers by means of a
single DMA context.

The use case is reception of more streams than there are IR DMA units
offered by the link layer.  This is already implemented by the older
ohci1394 + ieee1394 + raw1394 stack.  And as discussed recently on
linux1394-devel, this feature is occasionally used in practice.

The big drawbacks of this mode are that buffer layout and interrupt
generation necessarily differ from single-channel reception:  Headers
and trailers are not stripped from packets, packets are not aligned with
buffer chunks, interrupts are per buffer chunk, not per packet.

These drawbacks also cause a rather hefty code footprint to support this
rarely used OHCI-1394 feature.  (367 lines added, among them 94 lines of
added userspace ABI documentation.)

This implementation enforces that a multichannel reception context may
only listen to channels to which no single-channel context on the same
link layer is presently listening to.  OHCI-1394 would allow to overlay
single-channel contexts by the multi-channel context, but this would be
a departure from the present first-come-first-served policy of IR
context creation.

The implementation is heavily based on an earlier one by Jay Fenlason.
Thanks Jay.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Make a note on the seemingly unused linux/sched.h.
Rename an irritatingly named variable.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

ioctl_create_iso_context enforces ctx->header_size >= 4.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

firewire-ohci keeps book of which isochronous channels are occupied by
IR DMA contexts, so that there cannot be more than one context listening
to a certain channel.

If IR context creation failed due to an out-of-memory condition, this
bookkeeping leaked a channel.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

When we append to a DMA program, we need to ensure that the order in
which initialization of the new descriptors and update of the
branch_address of the old tail descriptor, as seen by the PCI device,
happen as intended.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

This adds nosy-dump, the userspace part of nosy, the IEEE 1394 traffic
sniffer for Texas Instruments PCILynx/ PCILynx2 based cards.  Author is
Kristian Høgsberg.

The files added here are taken from
git://anongit.freedesktop.org/~krh/nosy commit ee29be97 (2009-11-10)
with the following changes by Stefan Richter:
  - Parts pertaining to the kernel module removed from Makefile.
  - dist target removed from the Makefile.
  - Mentioned nosy-dump in the Kconfig help to nosy's kernel component.
  - Add copyright notice to nosy-dump.c.  This is a duplicate of the
    respective notice in the kernel component nosy.c except for a time
    span of 2002 - 2006, according to Kristian's git log.

"git shortlog decode-fcp.c list.h nosy-dump.[ch]" from nosy's git
repository:

Jonathan Woithe (1):
      Save logs on Ctrl-C

Kristian Høgsberg (11):
      Pull over nosy from mercurial repo.
      Remove some fields from default view, add logging feature.
      Use infinite time out for poll(), mark more detail fields.
      Fix byte ordering macro.
      Add decoding of iso data and lock packets.
      Add flag to indicate data length field.
      Add cycle start packet decoding, add --iso and --cycle-start flags.
      Distinguish between phy-packets and 0-length iso data.
      Fix transaction and stats view.
      Add simple AV/C decoder.
      Don't break down on big payloads.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Acked-by: NKristian Høgsberg <krh@bitplanet.net>

Replace home-grown printk wrapper macros by ones from kernel.h and
device.h.

Also raise the log level in set_phy_reg() from debug to error because
these are really error conditions.  Could even be WARN_ON.  Lower the
log level in the device probe and driver shutdown from notice to info.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

1.)  The DMA programs (struct pcl) are PCI-endian = little endian data
(except for the 3rd quadlet in a PCL which the controller does not
touch).  Annotate them as such.

Fix all accesses of the PCL to work with big endian CPUs also.  Not
actually tested, I only have a little endian PC to test with.  This
includes replacement of a bitfield struct pcl_status by open-coded
shift and mask operations.

2.)  The two __attribute__ ((packed)) at struct pcl are not really
required since it consists of u32/__le32 only, i.e. there will be no
padding with or without the attribute.

3.)  The received IEEE 1394 data are byteswapped by the controller from
IEEE 1394 endian = big endian to PCI endian = little endian because the
PCL_BIGENDIAN control bit is set.  Therefore annotate the DMA buffer as
a __le32 array.

Fix the one access of the DMA buffer (the check of the transaction code
of link packets) to work with big endian CPUs.  Also fix the two
accesses of the client bounce buffer (the reading of packet length).

4.)  Add a comment to the userspace ABI header that all of the data gets
out as little endian data, except for the timestamp which is CPU endian.
(We could make it little endian too, but why?  Vice versa, an ioctl
could be added to dump packet data in big endian byte order...)
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Fix race between nosy_open() and remove_card() by replacing the
unprotected array of card pointers by a mutex-protected list of cards.

Make card instances reference-counted and let each client hold a
reference.

Notify clients about card removal via POLLHUP in poll()'s events
bitmap; also let read() fail with errno=ENODEV if the card was removed
and everything in the buffer was read.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

and add a missing pci_disable_device() to device shutdown.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Untested, I don't have a PCILynx CardBus card.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

nosy_start/stop_snoop() and nosy_add/remove_client() are simple enough
to be inlined into their callers.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

nosy_start/stop_snoop() are always only called by the ioctl method, i.e.
with IRQs enabled.  packet_handler() and bus_reset_handler() are always
only called by the IRQ handler.  Hence neither one needs to track IRQ
flags.

To underline the call context of packet_handler() and
bus_reset_handler(), rename these functions to *_irq_handler().
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

nosy_stop_snoop() would blow up the second time it was called without
nosy_start_snoop() in between.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The required serialization of NOSY_IOC_START and NOSY_IOC_STOP is
already provided by the client_list_lock.

NOSY_IOC_FILTER does not really require serialization since accesses
to tcode_mask are atomic on any sane CPU architecture.  Nevertheless,
make it explicit that we want this to be atomic by means of
client_list_lock (which also surrounds the other tcode_mask access in
the IRQ handler).  While we are at it, change the type of tcode_mask to
u32 for consistency with the user API.

NOSY_IOC_GET_STATS does not require serialization against itself.  But
there is a bug here regarding concurrent updates of the two counters
by the IRQ handler.  Fix it by taking the client_list_lock in this ioctl
too.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Extend copyright note to 2007, c.f. Kristian's git log.

Includes:
  - replace some <asm/*.h> by <linux/*.h>
  - add required indirectly included <linux/spinlock.h>
  - order alphabetically

Coding style related changes:
  - change to utf8
  - normalize whitespace
  - normalize comment style
  - remove usages of __FUNCTION__
  - remove an unnecessary cast from void *

Const and static declarations:
  - driver_name is not const in pci_driver.name, drop const qualifier
  - driver_name can be taken from KBUILD_MODNAME
  - the global variable minors[] can and should be static
  - constify struct file_operations instance

Data types:
  - Remove unused struct member struct packet.code.  struct packet is
    only used for driver-internal bookkeeping; it does not appear on the
    wire or in DMA programs or the userspace ABI.  Hence the unused
    member .code can be removed without worries.

Preprocessor macros:
  - unroll a preprocessor macro that containd a return
  - use list_for_each_entry

Printk:
  - add missing terminating \n in some format strings
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

This adds the traffic sniffer driver for Texas Instruments PCILynx/
PCILynx2 based cards.  The use cases for nosy are analysis of
nonstandard protocols and as an aid in development of drivers,
applications, or firmwares.

Author of the driver is Kristian Høgsberg.  Known contributers are
Jody McIntyre and Jonathan Woithe.

Nosy programs PCILynx chips to operate in promiscuous mode, which is a
feature that is not found in OHCI-1394 controllers.  Hence, only special
hardware as mentioned in the Kconfig help text is suitable for nosy.

This is only the kernelspace part of nosy.  There is a userspace
interface to it, called nosy-dump, proposed to be added into the tools/
subdirectory of the kernel sources in a subsequent change.  Kernelspace
and userspave component of nosy communicate via a 'misc' character
device file called /dev/nosy with a simple ioctl() and read() based
protocol, as described by nosy-user.h.

The files added here are taken from
git://anongit.freedesktop.org/~krh/nosy commit ee29be97 (2009-11-10)
with the following changes by Stefan Richter:
  - Kconfig and Makefile hunks are written from scratch.
  - Commented out version printk in nosy.c.
  - Included missing <linux/sched.h>, reported by Stephen Rothwell.

"git shortlog nosy{-user.h,.c,.h}" from nosy's git repository:

Jonathan Woithe (2):
      Nosy updates for recent kernels
      Fix uninitialised memory (needed for 2.6.31 kernel)

Kristian Høgsberg (5):
      Pull over nosy from mercurial repo.
      Use a misc device instead.
      Add simple AV/C decoder.
      Don't break down on big payloads.
      Set parent device for misc device.

As a low-level IEEE 1394 driver, its files are placed into
drivers/firewire/ although nosy is not part of the firewire driver
stack.

I am aware of the following literature from Texas Instruments about
PCILynx programming:
      SCPA020A - PCILynx 1394 to PCI Bus Interface TSB12LV21BPGF
                 Functional Specification
      SLLA023  - Initialization and Asynchronous Programming of the
                 TSB12LV21A 1394 Device
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Acked-by: NKristian Høgsberg <krh@bitplanet.net>

In both the ieee1394 stack and the firewire stack, the core treats
kernelspace drivers better than userspace drivers when it comes to
CSR address range allocation:  The former may request a register to be
placed automatically at a free spot anywhere inside a specified address
range.  The latter may only request a register at a fixed offset.

Hence, userspace drivers which do not require a fixed offset potentially
need to implement a retry loop with incremented offset in each retry
until the kernel does not fail allocation with EBUSY.  This awkward
procedure is not fundamentally necessary as the core already provides a
superior allocation API to kernelspace drivers.

Therefore change the ioctl() ABI by addition of a region_end member in
the existing struct fw_cdev_allocate.  Userspace and kernelspace APIs
work the same way now.

There is a small cost to pay by clients though:  If client source code
is required to compile with older kernel headers too, then any use of
the new member fw_cdev_allocate.region_end needs to be enclosed by
#ifdef/#endif directives.  However, any client program that seriously
wants to use address range allocations will require a kernel of cdev ABI
version >= 4 at runtime and a linux/firewire-cdev.h header of >= 4
anyway.  This is because v4 brings FW_CDEV_EVENT_REQUEST2.  The only
client program in which build-time compatibility with struct
fw_cdev_allocate as found in older kernel headers makes sense is
libraw1394.

(libraw1394 uses the older broken FW_CDEV_EVENT_REQUEST to implement a
makeshift, incorrect transaction responder that does at least work
somewhat in many simple scenarios, relying on guesswork by libraw1394
and by libraw1394 based applications.  Plus, address range allocation
and transaction responder is only one of many features that libraw1394
needs to provide, and these other features need to work with kernel and
kernel-headers as old as possible.  Any new linux/firewire-cdev.h based
client that implements a transaction responder should never attempt to
do it like libraw1394;  instead it should make a header and kernel of v4
or later a hard requirement.)

While we are at it, update the struct fw_cdev_allocate documentation to
better reflect the recent fw_cdev_event_request2 ABI addition.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

region->end is defined as an upper bound of the requested address range,
exclusive --- i.e. as an address outside of the range in which the
requested CSR is to be placed.

Hence 0x0001,0000,0000,0000 is the biggest valid region->end, not
0x0000,ffff,ffff,fffc like the current check asserted.

For simplicity, the fix drops the region->end & 3 test because there is
no actual problem with these bits set in region->end.  The allocated
address range will be quadlet aligned and of a size of multiple quadlets
due to the checks for region->start & 3 and handler->length & 3 alone.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

This extends the FW_CDEV_IOC_SEND_PHY_PACKET ioctl() for /dev/fw* to be
useful for ping time measurements.  One application for it would be gap
count optimization in userspace that is based on ping times rather than
hop count.  (The latter is implemented in firewire-core itself but is
not applicable to beta PHYs that act as repeater.)
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Add an FW_CDEV_IOC_RECEIVE_PHY_PACKETS ioctl() and
FW_CDEV_EVENT_PHY_PACKET_RECEIVED poll()/read() event for /dev/fw*.
This can be used to get information from remote PHYs by remote access
PHY packets.

This is also the 2nd half of the functionality (the receive part) to
support a userspace implementation of a VersaPHY transaction layer.

Safety considerations:

  - PHY packets are generally broadcasts, hence some kind of elevated
    privileges should be required of a process to be able to listen in
    on PHY packets.  This implementation assumes that a process that is
    allowed to open the /dev/fw* of a local node does have this
    privilege.

    There was an inconclusive discussion about introducing POSIX
    capabilities as a means to check for user privileges for these
    kinds of operations.

Other limitations:

  - PHY packet reception may be switched on by ioctl() but cannot be
    switched off again.  It would be trivial to provide an off switch,
    but this is not worth the code.  The client should simply close()
    the fd then, or just ignore further events.

  - For sake of simplicity of API and kernel-side implementation, no
    filter per packet content is provided.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Add an FW_CDEV_IOC_SEND_PHY_PACKET ioctl() for /dev/fw* which can be
used to implement bus management related functionality in userspace.

This is also half of the functionality (the transmit part) that is
needed to support a userspace implementation of a VersaPHY transaction
layer.

Safety considerations:

  - PHY packets are generally broadcasts and may have interesting
    effects on PHYs and the bus, e.g. make asynchronous arbitration
    impossible due to too low gap count.  Hence some kind of elevated
    privileges should be required of a process to be able to send
    PHY packets.  This implementation assumes that a process that is
    allowed to open the /dev/fw* of a local node does have this
    privilege.

    There was an inconclusive discussion about introducing POSIX
    capabilities as a means to check for user privileges for these
    kinds of operations.

  - The kernel does not check integrity of the supplied packet data.
    That would be far too much code, considering the many kinds of
    PHY packets.  A process which got the privilege to send these
    packets is trusted to do it correctly.

Just like with the other "send packet" ioctls, a non-blocking API is
chosen; i.e. the ioctl may return even before AT DMA started.  After
transmission, an event for poll()/read() is enqueued.  Most users are
going to need a blocking API, but a blocking userspace wrapper is easy
to implement, and the second of the two existing libraw1394 calls
raw1394_phy_packet_write() and raw1394_start_phy_packet_write() can be
better supported that way.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

to make the correspondence of ioctl numbers and handlers more obvious.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

core-transaction.c transmit_complete_callback() and close_transaction()
expect packet callback status to be an ACK or RCODE, and ACKs get
translated to RCODEs for transaction callbacks.

An old comment on the packet callback API (been there from the initial
submission of the stack) and the dummy_driver implementation of
send_request/send_response deviated from this as they also included
-ERRNO in the range of status values.

Let's narrow status values down to ACK and RCODE to prevent surprises.
RCODE_CANCELLED is chosen as the dummy_driver's RCODE as its meaning of
"transaction timed out" comes closest to what happens when a transaction
coincides with card removal.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Bus resets which are triggered
  - by the kernel drivers after updates of the local nodes' config ROM,
  - by userspace software via ioctl
shall be deferred until after >=2 seconds after the last bus reset.

If multiple modifications of the local nodes' config ROM happen in a row,
only a single bus reset should happen after them.

When the local node's link goes from inactive to active or vice versa,
and at the two occasions of bus resets mentioned above --- and if the
current gap count differs from 63 --- the bus reset should be preceded
by a PHY configuration packet that reaffirms the gap count.  Otherwise a
bus manager would have to reset the bus again right after that.

This is necessary to promote bus stability, e.g. leave grace periods for
allocations and reallocations of isochronous channels and bandwidth,
SBP-2 reconnections etc.; see IEEE 1394 clause 8.2.1.

This change implements all of the above by moving bus reset initiation
into a delayed work (except for bus resets which are triggered by the
bus manager workqueue job and are performed there immediately).  It
comes with a necessary addition to the card driver methods that allows
to get the current gap count from PHY registers.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

When a descriptor was added or removed to the local node's config ROM,
userspace clients which had a local node's /dev/fw* open did not receive
any fw_cdev_event_bus_reset for poll()/read() consumption.

The cause was that the core-device.c facility which re-reads the config
ROM of the bus reset initiator node missed to call the fw_device update
function.  The fw_units are destroyed and newly added, but their parent
stays and needs to be updated.
Reported-by: NJay Fenlason <fenlason@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The FW_ISO_ constants of the in-kernel API of firewire-core and
FW_CDEV_ISO_ constants of the userspace API of firewire-core have
nothing to do with each other --- except that the core-cdev.c
implementation relies on them having the same values.

Hence put some compile-time assertions into core-cdev.c.  It's lame but
I prefer it over including the userspace API header into the kernelspace
API header and defining kernelspace API constants from userspace API
constants.  Nor do I want to expose the kernelspace constants in one of
the two firewire headers that are exported to userland since this only
concerns the core-cdev.c implementation.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The present inline documentation of the fw_send_request() in-kernel API
refers to userland code that is not applicable to kernel drivers at all.
Reported-by: NBen Gamari <bgamari.foss@gmail.com>

While we are at fixing the whole documentation of fw_send_request(),
also improve the rest of firewire-core's kerneldoc comments:
  - Add a bit of text concerning fw_run_transaction()'s call parameters.
  - Append () to function names and tab-align parameter descriptions as
    suggested by the example in Documentation/kernel-doc-nano-HOWTO.txt.
  - Remove kerneldoc markers from comments on static functions.
  - Remove outdated parameter descriptions at build_tree().
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Check that the data length of a write quadlet request actually is large
enough for a quadlet.  Otherwise, fw_fill_request could access the four
bytes after the end of the outbound_transaction_event structure.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>

Modification of Clemens' change:  Consolidate the check into
init_request() which is used by the affected ioctl_send_request() and
ioctl_send_broadcast_request() and the unaffected
ioctl_send_stream_packet(), to save a few lines of code.

Note, since struct outbound_transaction_event *e is slab-allocated, such
an out-of-bounds access won't hit unallocated memory but may result in a
(virtually impossible to exploit) information disclosure.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Fix an obscure ABI feature that is a bit of a hassle to implement.
However, somebody put it into the ABI, so let's fill in a sensible
value there.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

This is a workqueue job and always entered with IRQs enabled.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The problem:

A target-like userspace driver, e.g. AV/C target or SBP-2/3 target,
needs to be able to act as responder and requester.  In the latter role,
it needs to send requests to nods from which it received requests.  This
is currently impossible because fw_cdev_event_request lacks information
about sender node ID.
Reported-by: NJay Fenlason <fenlason@redhat.com>

Libffado + libraw1394 + firewire-core is currently unable to drive two
or more audio devices on the same bus.
Reported-by: NArnold Krille <arnold@arnoldarts.de>

This is because libffado requires destination node ID of FCP requests
and sender node ID of FCP responses to match.  It even prohibits
libffado from working with a bus on which libraw1394 opens a /dev/fw* as
default ioctl device that does not correspond with the audio device.
This is because libraw1394 does not receive the sender node ID from the
kernel.

Moreover, fw_cdev_event_request makes it impossible to tell unicast and
broadcast write requests apart.

The fix:

Add a replacement of struct fw_cdev_event_request request, boringly
called struct fw_cdev_event_request2.  The new event will be sent to a
userspace client instead of the old one if the client claims
compatibility with <linux/firewire-cdev.h> ABI version 4 or later.

libraw1394 needs to be extended to make use of the new event, in order
to properly support libffado and other FCP or address range mapping
users who require correct sender node IDs.

Further notes:

While we are at it, change back the range of possible values of
fw_cdev_event_request.tcode to 0x0...0xb like in ABI version <= 3.
The preceding change "firewire: expose extended tcode of incoming lock
requests to (userspace) drivers" expanded it to 0x0...0x17 which could
catch sloppily coded clients by surprise.  The extended range of codes
is only used in the new fw_cdev_event_request2.tcode.

Jay and I also suggested an alternative approach to fix the ABI for
incoming requests:  Add an FW_CDEV_IOC_GET_REQUEST_INFO ioctl which can
be called after reception of an fw_cdev_event_request, before issuing of
the closing FW_CDEV_IOC_SEND_RESPONSE ioctl.  The new ioctl would reveal
the vital information about a request that fw_cdev_event_request lacks.
Jay showed an implementation of this approach.

The former event approach adds 27 LOC of rather trivial code to
core-cdev.c, the ioctl approach 34 LOC, some of which is nontrivial.
The ioctl approach would certainly also add more LOC to userspace
programs which require the expanded information on inbound requests.
This approach is probably only on the lighter-weight side in case of
clients that want to be compatible with kernels that lack the new
capability, like libraw1394.  However, the code to be added to such
libraw1394-like clients in case of the event approach is a straight-
forward additional switch () case in its event handler.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

When a remote device does a LOCK_REQUEST, the core does not pass
the extended tcode to userspace.  This patch makes it use the
juju-specific tcodes listed in firewire-constants.h for incoming
requests.
Signed-off-by: NJay Fenlason <fenlason@redhat.com>

This matches how tcode in the API for outbound requests is treated.
Affects kernelspace and userspace drivers alike, but at the moment there
are no kernespace drivers that receive lock requests.

Split out from a combo patch, slightly reordered, changelog reworded.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

libraw1394 v2.0.0...v2.0.5 takes FW_CDEV_VERSION from an externally
installed header file and uses it to declare its own implementation
level in FW_CDEV_IOC_GET_INFO.  This is wrong; it should set the real
version for which it was actually written.

If we add features to the kernel ABI that require the kernel to check
a client's implementation level, we can not trust the client version if
it was set from FW_CDEV_VERSION.

Hence freeze FW_CDEV_VERSION at the current value (no damage has been
done yet), clearly document FW_CDEV_VERSION as a dummy version and what
clients are expected to do with fw_cdev_get_info.version, and use a new
defined constant (which is not placed into the exported header file) as
kernel implementation level.

Note, in order to check in client program source code which features are
present in an externally installed linux/firewire-cdev.h, use
preprocessor directives like
  #ifdef FW_CDEV_IOC_ALLOCATE_ISO_RESOURCE
or
  #ifdef FW_CDEV_EVENT_ISO_RESOURCE_ALLOCATED
instead of a check of FW_CDEV_VERSION.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>