by the number of available isochronous DMA contexts and active quirks
which is occasionally useful information.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

This bug was present in firewire-ohci since day one:  The number of
available isochronous receive DMA contexts was mixed up with that of
available isochronous transmit DMA contexts.

This is harmless on a few chips which offer the same number of contexts
in both directions, but most chips nowadays implement only the standard
minimum of 4 IR contexts, but 8 IT contexts.  If a user attempted to run
a lot of IR contexts at once, results with more than four were therefore
unpredictable.  I suppose the controller would simply refuse to start
DMA of any unimplemented context.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

This way, we can advise users of precompiled kernel packages to test
existing quirk fixes on chips which have not been listed yet, without
them having to build a kernel from source.

Note, to use this feature on a machine with more than one controller,
steps like these are necessary:
# lspci | grep 1394
# ls /sys/bus/pci/drivers/firewire_ohci/
# echo -n "0000:03:02.0" > /sys/bus/pci/drivers/firewire_ohci/unbind
# echo 2 > /sys/module/firewire_ohci/parameters/quirks
# echo -n "0000:03:02.0" > /sys/bus/pci/drivers/firewire_ohci/bind
# echo 0 > /sys/module/firewire_ohci/parameters/quirks

The parameter can also be used to switch off quirk flags that were
hardwired into firewire-ohci's quirks table.  Simply specify a non-zero
quirks value but without any known flags, e.g. 0x100.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

We don't have a lot of quirks to take into account (especially since
dual-buffer IR is out of the picture), but still, a table-based approach
is more organized than a series of if () clauses.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The config_rom struct members are only accessed during relatively
infrequent self-ID-complete interrupts and only if the local config ROM
was changed, while the ar_, at_, ir_, it_ members are used very
frequently during I/O.  Hence move the config_rom members further down.

More importantly, make the huge self_id_buffer member the last one; this
is only accessed in self-ID-complete interrupts.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

This code was no longer used since 2.6.33, "firewire: ohci: always use
packet-per-buffer mode for isochronous reception" commit 090699c0.  If
anybody needs this code in the future for special purposes, it can be
brought back in.  But it must not be re-enabled by default; drivers
(kernelspace or userspace drivers) should only get this mode if they
explicitly request it.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

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

from array of char to union of structs.  I already used a union to size
the buffer which holds ioctl arguments; more consequent is to define it
as an instance of this union in the first place.

Also rename several local variables from "request" to "a"(rgument) since
the term request can be mistaken to mean a transaction subaction, e.g.
an instance of struct fw_request.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The system time from CLOCK_REALTIME is not monotonic, hence problematic
for the main user of the FW_CDEV_IOC_GET_CYCLE_TIMER ioctl.  This issue
exists in its successor ABI, i.e. raw1394, too.
http://subversion.ffado.org/ticket/242

We now offer an alternative ioctl which lets the caller choose between
CLOCK_REALTIME, CLOCK_MONOTONIC, and CLOCK_MONOTONIC_RAW as source of
the local time, very similar to the clock_gettime libc function.  The
format of the local time return value matches that of clock_gettime
(seconds and nanoseconds, instead of a single microseconds value from
the existing ioctl).
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

according to what it really does.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

If a device exposes a sparsely populated configuration ROM,
firewire-core's sysfs interface and character device file interface
showed random data in the gaps between config ROM blocks.  Fix this by
zero-initialization of the config ROM reader's scratch buffer.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The stack size of 16 was artificially chosen and may be too small in
extreme cases.  A device won't be accessible then.

Since it doesn't really matter to the slab allocator whether we ask for
1088 bytes or 2048 bytes of scratch memory, just allocate 2048 bytes for
the sum of temporary config ROM image and stack, and we will never ever
overflow the stack (because there simply can't be more stack items than
ROM entries).
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

It never happened yet, but better safe than sorry:  If a device's config
ROM contains a block which overlaps the boundary at 0xfffff00007ff, just
ignore that one block instead of refusing to add the device
representation.  That way, upper layers (kernelspace or userspace
drivers) might still be able to use the device to some degree.

That's better than total inaccessibility of the device.  Worse, the core
would have logged only a generic "giving up on config rom" message which
could only be debugged by feeding a firewire-ohci debug logging session
through a config ROM interpreter, IOW would likely remain undiagnosed.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The Panasonic AG-DV2500 tape deck contains an invalid entry in its
configuration ROM root directory:  A leaf pointer with the undefined key
ID 0 and an offset that points way out of the standard config ROM area.
This caused firewire-core to dismiss the device with the generic log
message "giving up on config rom for node id...", after which it was of
course impossible to access the tape deck with dvgrab or any other
program.  https://bugzilla.redhat.com/show_bug.cgi?id=449252#c29

The fix is to simply ignore this invalid ROM entry and proceed to read
the valid rest of the ROM.  There is a catch though:  When the kernel
later iterates over the ROM, it would be nasty having to check again for
such too large ROM offsets.  Therefore we manipulate the defective or
unsupported ROM entry to become a harmless immediate entry that won't
have any side effects later (an entry with the value 0x00000000).

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

The current implementation of Bus_Time read access was buggy since it
did not ensure that Bus_Time.second_count_hi and second_count_lo came
from the same 128 seconds period.
Reported-by: NHåkan Johansson <f96hajo@chalmers.se>

Instead of a fix, remove Bus_Time register support altogether.  The spec
requires all cycle master capable nodes to implement this (all Linux
nodes are cycle master capable) while it also says that it "may" be
initialized by the bus manager or by the IRM standing in for a bus
manager.  (Neither Linux' firewire-core nor ieee1394 nodemgr implement
this.)

Since we cannot rely on Bus_Time having been initialized by a bus
manager, it is better to return an error instead of a nonsensical value
on a read request to Bus_Time.

Alternatively, we could fix the Bus_Time read integrity bug _and_
implement (a) cycle master's write support of the register as well as
(b) bus manager's Bus_Time initialization service, i.e. preservation of
the Bus_Time when the cycle master node of a bus changes.  However, that
would be quite some code for a feature that is unreliable to begin with
and very likely unused in practice.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

ohci:  Break out of the retry loop if too many attempts were necessary.
This may theoretically happen if the chip is fatally defective or if the
get_cycle_timer ioctl was performed after a CardBus controller was
ejected.

Also micro-optimize the loop by re-using the last two register reads in
the next iteration, remove a questionable inline keyword, and shuffle a
comment around.

core:  ioctl_get_cycle_timer() is always called with interrupts on,
therefore local_irq_save() can be replaced by local_irq_disable().
Disabled local IRQs imply disabled preemption, hence preempt_disable()
can be removed.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Discussed in "read_cycle_timer backwards for sub-cycle 0000, 0001",
http://thread.gmane.org/gmane.linux.kernel.firewire.devel/13704

Known bad controllers:
  ALi M5271, listed by lspci as M5253 [10b9:5253]
  NEC OrangeLink [1033:00cd] (rev 03)
  NEC uPD72874 [1033:00f2] (rev 01)
  VIA VT6306 [1106:3044] (rev 46)
  VIA VT6308P, listed by lspci as rev c0
Reported-by: NPieter Palmers <pieterp@joow.be>
Reported-by: NHåkan Johansson <f96hajo@chalmers.se>
Reported-by: NClemens Ladisch <clemens@ladisch.de>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

VIA controllers sometimes return an inconsistent value when reading the
isochronous cycle timer register.  To work around this, read the
register multiple times and add consistency checks.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Reported-by: NPieter Palmers <pieterp@joow.be>
Reported-by: NHåkan Johansson <f96hajo@chalmers.se>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

In isochronous transmit DMA descriptors, link the skip address pointer
back to the descriptor itself.  When a cycle is lost, the controller
will send the packet in the next cycle, instead of terminating the
entire DMA program.

There are two reasons for this:

* This behaviour is compatible with the old IEEE1394 stack.  Old
  applications would not expect the DMA program to stop in this case.

* Since the OHCI driver does not report any uncompleted packets, the
  context would stop silently; clients would not have any chance to
  detect and handle this error without a watchdog timer.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>

Pieter Palmers notes:

"The reason I added this retry behavior to the old stack is because some
cards now and then fail to send a packet (e.g. the o2micro card in my
dell laptop).  I couldn't figure out why exactly this happens, my best
guess is that the card cannot fetch the payload data on time.  This
happens much more frequently when sending large packets, which leads me
to suspect that there are some contention issues with the DMA that fills
the transmit FIFO.

In the old stack it was a pretty critical issue as it resulted in a
freeze of the userspace application.

The omission of a packet doesn't necessarily have to be an issue.  E.g.
in IEC61883 streams the DBC field can be used to detect discontinuities
in the stream.  So as long as the other side doesn't bail when no
[packet] is present in a cycle, there is not really a problem.

I'm not convinced though that retrying is the proper solution, but it is
simple and effective for what it had to do.  And I think there are no
reasons not to do it this way.  Userspace can still detect this by
checking the cycle the descriptor was sent in."

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (changelog, comment)

In the transmit path of firewire-net (IPv4 over 1394), the following
race condition may occur:
  - The networking soft IRQ inserts a datagram into the 1394 async
    request transmit DMA.
  - The 1394 async transmit completion tasklet runs to finish cleaning
    up (unlink datagram from list of pending ones, release skb and
    outbound 1394 transaction object) --- before the networking soft IRQ
    had a chance to proceed and add the datagram to the list of pending
    datagrams.

This caused a panic in the 1394 async transmit completion tasklet when
it dereferenced unitialized list heads:
http://bugzilla.kernel.org/show_bug.cgi?id=15077

The fix is to add checks in the tx soft IRQ and in the tasklet to
determine which of these two is the last referrer to the transaction
object.  Then handle the cleanup of the object by the last referrer
rather than assuming that the tasklet is always the last one.

There is another similar race:  Between said tasklet and fwnet_close,
i.e. at ifdown.  However, that race is much less likely to occur in
practice and shall be fixed in a separate update.
Reported-by: NИлья Басин <basinilya@gmail.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Unsurprisingly, Texas Instruments TSB43AB23 exhibits the same behaviour
as TSB43AB22/A in dual buffer IR DMA mode:  If descriptors are located
at physical addresses above the 31 bit address range (2 GB), the
controller will overwrite random memory.  With luck, this merely
prevents video reception.  With only a little less luck, the machine
crashes.

We use the same workaround here as with TSB43AB22/A:  Switch off the
dual buffer capability flag and use packet-per-buffer IR DMA instead.
Another possible workaround would be to limit the coherent DMA mask to
31 bits.

In Linux 2.6.33, this change serves effectively only as documentation
since dual buffer mode is not used for any controller anymore.  But
somebody might want to re-enable it in the future to make use of
features of dual buffer DMA that are not available in packet-per-buffer
mode.

In Linux 2.6.32 and older, this update is vital for anyone with this
controller, more than 2 GB RAM, a 64 bit kernel, and FireWire video or
audio applications.

We have at least four reports:
http://bugzilla.kernel.org/show_bug.cgi?id=13808
http://marc.info/?l=linux1394-user&m=126154279004083
https://bugzilla.redhat.com/show_bug.cgi?id=552142
http://marc.info/?l=linux1394-user&m=126432246128386

Reported-by: Paul Johnson
Reported-by: Ronneil Camara
Reported-by: G Zornetzer
Reported-by: Mark Thompson
Cc: stable@kernel.org
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Commit db5d247a "firewire: fix use of multiple AV/C devices, allow
multiple FCP listeners" introduced a regression into 2.6.33-rc3:
The core freed payloads of incoming requests to FCP_Request or
FCP_Response before a userspace driver accessed them.

We need to copy such payloads for each registered userspace client
and free the copies according to the lifetime rules of non-FCP client
request resources.

(This could possibly be optimized by reference counts instead of
copies.)

The presently only kernelspace driver which listens for FCP requests,
firedtv, was not affected because it already copies FCP frames into an
own buffer before returning to firewire-core's FCP handler dispatcher.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Presently, firewire-core only checks whether descriptors that are to be
added by userspace drivers to the local node's config ROM do not exceed
a size of 256 quadlets.  However, the sum of the bare minimum ROM plus
all descriptors (from firewire-core, from firewire-net, from userspace)
must not exceed 256 quadlets.

Otherwise, the bounds of a statically allocated buffer will be
overwritten.  If the kernel survives that, firewire-core will
subsequently be unable to parse the local node's config ROM.

(Note, userspace drivers can add descriptors only through device files
of local nodes.  These are usually only accessible by root, unlike
device files of remote nodes which may be accessible to lesser
privileged users.)

Therefore add a test which takes the actual present and required ROM
size into account for all descriptors of kernelspace and userspace
drivers.

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

The id_table field of the struct pci_driver is constant in <linux/pci.h>
so it is worth to make pci_table also constant.  Found with Coccinelle.
Signed-off-by: NMárton Németh <nm127@freemail.hu>
Cc: Julia Lawall <julia@diku.dk>
Cc: cocci@diku.dk
Signed-off-by: Stefan Richter stefanr@s5r6.in-berlin.de> (changelog)

Several config ROM related functions only peek at the ROM cache; mark
their arguments as const pointers.  Ditto fw_device.config_rom and
fw_unit.directory, as the memory behind them is meant to be write-once.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Update the Kconfig help texts of both stacks to encourage a general move
from the older to the newer drivers.  However, do not label ieee1394 as
"Obsolete" yet, as the newer drivers have not been deployed as default
stack in the majority of Linux distributions yet, and those who start
doing so now may still want to install the old drivers as fallback for
unforeseen issues.

Since Linux 2.6.32, FireWire audio devices can be driven by the newer
firewire driver stack too, hence remove an outdated comment about audio
devices.  Also remove comments about library versions since the 2nd
generation of libraw1394 and libdc1394 is now in common use; details on
library versions can be read at the wiki link from the help texts.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Witespace and comment changes, and a different way to say i + 1 < end.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The core (sysfs attributes), the firedtv driver, and possible future
drivers all read strings from some configuration ROM directory.  Factor
out the generic code from show_text_leaf() into a new helper function,
modified slightly to handle arbitrary buffer sizes.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

This is a minimal change meant for the short term:  Never set the
ohci->use_dualbuffer flag to true.

There are two reasons to do so:

  - Packet-per-buffer mode and dual-buffer mode do not behave the same
    under certain circumstances, notably if several packets are covered
    by a single fw_cdev_iso_packet descriptor.
    http://marc.info/?l=linux1394-devel&m=124965653718313
    Therefore the driver stack should not silently choose one or the
    other mode but should leave the choice to the high-level driver
    (regardless if kernel driver or userspace driver).  Or simply always
    only offer packet-per-buffer mode, since a considerable number of
    controllers, even current ones, does not offer dual-buffer support.

  - Even under circumstances where packet-per-buffer mode and
    dual-buffer mode behave exactly the same --- notably when used
    through libraw1394, libdc1394, as well as the current two kernel
    drivers which use isochronous reception (firewire-net and firedtv)
    --- we are still faced with the problem that several OHCI 1.1
    controllers have bugs in dual-buffer mode.  Although it looks like
    we have identified most of those buggy controllers by now, we
    cannot be quite sure about that.

So, use packet-per-buffer by default from now on.  This change should
be followed up by a more complete solution:  Either extend the
in-kernel API and the userspace ABI by a choice between the two IR modes
or remove all dual-buffer related code from firewire-ohci.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

If copy_from_user in an FW_CDEV_IOC_SEND_RESPONSE ioctl failed, the
fw_request pointed to by the inbound_transaction_resource is no
longer referenced and needs to be freed.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Control of more than one AV/C device at once --- e.g. camcorders, tape
decks, audio devices, TV tuners --- failed or worked only unreliably,
depending on driver implementation.  This affected kernelspace and
userspace drivers alike and was caused by firewire-core's inability to
accept multiple registrations of FCP listeners.

The fix allows multiple address handlers to be registered for the FCP
command and response registers.  When a request for these registers is
received, all handlers are invoked, and the Firewire response is
generated by the core and not by any handler.

The cdev API does not change, i.e., userspace is still expected to send
a response for FCP requests; this response is silently ignored.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (changelog, rebased, whitespace)

Queueing to receive an ISO packet with a payload length of zero
silently does nothing in dualbuffer mode, and crashes the kernel in
packet-per-buffer mode.  Return an error in dualbuffer mode, because
the DMA controller won't let us do what we want, and work correctly in
packet-per-buffer mode.
Signed-off-by: NJay Fenlason <fenlason@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Cc: stable@kernel.org

That is "success", "unknown", "through", "performance", "[re|un]mapping"
, "access", "default", "reasonable", "[con]currently", "temperature"
, "channel", "[un]used", "application", "example","hierarchy", "therefore"
, "[over|under]flow", "contiguous", "threshold", "enough" and others.
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Here is the final set of patches I used to get ffado to work with the
new firewire stack.  With these patches, I was able to start ardour
and record from and playback to my PreSonus Inspire1394 from a
(mostly) Fedora 12 system.
Signed-off-by: NJay Fenlason <fenlason@redhat.com>

Until now, firewire-ohci exposed only the transmit cycle of the last
transmitted packet at each isochronous transmit complete event.  This
made it impossible for FFADO (FireWire audio drivers in userspace) to
synchronize audio-out streams.  The fix is to store the timestamp of
each packet in the iso xmit event.  As a bonus, the transfer status is
stored too.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Calling the START_ISO ioctl with a nonnegative cycle paramater has
never worked.  Last night I got around to figuring out why.  Most of
this patch is a big comment explaining why we enable an interrupt
source then don't actually do anything when we get one.  As the
comment says, we should do more, but we don't have a way to tell
userspace what happened. . .
Signed-off-by: NJay Fenlason <fenlason@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (edited comment)

Replace a hardcoded buffer size by a sizeof union {}.  This shrinks the
stack-allocated ioctl argument buffer from 256 to 40 bytes.  (This is
not much, but subsequent stack usage particularly by the queue_iso ioctl
handler adds up.)

The new form is also easier to keep up to date than a hardcoded size if
more ioctls are added.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

I was told that there are obscure architectures with non-coherent DMA
which may DMA-map to bus address 0.  We shall not use 0 as a magic
number of uninitialized bus address variables.

The packet->payload_length > 0 test cannot be used either (except in
at_context_queue_packet) because local requests are not DMA-mapped
regardless of payload_length.  Hence add a state flag to struct
fw_packet.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

In the code path which creates request packets, clearly mark a switch
branch which must never be reached with a WARN.

In the code path which creates response packets, replace a BUG by a
friendlier to debug WARN.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The Topology Map of the local node was created in CPU byte order,
then a temporary big endian copy was created to compute the CRC,
and when a read request to the Topology Map arrived it had to be
converted to big endian byte order again.

We now generate it in big endian byte order in the first place.
This also rids us of 1000 bytes stack usage in tasklet context.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Move the static config ROM buffer into the scope of the two callers of
generate_config_rom().  That way the ROM length can be passed over as
return value rather than through a pointer argument.

It also becomes more obvious that accesses to the config ROM buffer have
to be serialized and how this is accomplished.  And firewire-core.ko
shrinks a bit as well.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>