This adds the attribute /sys/bus/firewire/devices/fw[0-9]+/units.  It
can be used in udev rules like the following ones:

# IIDC devices: industrial cameras and some webcams
SUBSYSTEM=="firewire", ATTR{units}=="*0x00a02d:0x00010?*", GROUP="video"

# AV/C devices: camcorders, set-top boxes, TV sets, audio devices, ...
SUBSYSTEM=="firewire", ATTR{units}=="*0x00a02d:0x010001*", GROUP="video"

Background:

firewire-core manages two device types:
  - fw_device is a FireWire node.  A character device file is associated
    with it.
  - fw_unit is a unit directory on a node.  Each fw_device may have 0..n
    children of type fw_unit.  The units tell us what kinds of protocols
    a node implements.

We want to set ownership or ACLs or permissions of the character device
file of an fw_device, or/and create symlinks to it, based on available
protocols.  Until now udev rules had to look at the fw_unit devices and
then modify their parent's character device file accordingly.  This is
problematic for two reasons:  1) It happens sometime after the creation
of the fw_device, 2) an access policy may require that information from
all children is evaluated before a decision about the parent is made.

Problem 1) can ultimately not be avoided since this is the nature of
FireWire nodes:  They may add or remove unit directories at any point in
time.

However, we can still help userland a lot by providing the protocol type
information of all units in a summary sysfs attribute directly at the
fw_device.  This way,
   - the information is immediately available at the affected device
     when userspace goes about to handle an ADD or CHANGE event of the
     fw_device,
   - with most policies, it won't be necessary anymore to dig through
     child attributes.

The new attribute is called "units".  It contains space-separated tuples
of specifier_id and version of each present unit.  The delimiter within
tuples is a colon.  Specifier_id and version are printed as 0x%06x.

Here is an example of a node which implements an IPv4 unit and an IPv6
unit:  $ cat /sys/bus/firewire/devices/fw2/units
0x00005e:0x000001 0x00005e:0x000002
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

My recently added test for a device being local in fw-cdev.c got it
slightly wrong:  Comparisons of node IDs are only valid if the
generation is current, which I forgot to check.  Normally, serialization
by card->lock takes care of this, but a device in FW_DEVICE_GONE state
will necessarily have a wrong generation and invalid node_id.

The "is it local?" check is made 100% correct and simpler now by means
of a struct fw_device flag which is set at fw_device creation.

Besides the fw-cdev site which was to be fixed, there is another site
which can make use of the new flag, and an RFC-2734 driver will benefit
from it too.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Cache the test result of whether a device implements BROADCAST_CHANNEL.
This minimizes traffic on the bus after each bus reset.  A majority of
devices does not implement BROADCAST_CHANNEL.

Remove busy retries; just rely on the hardware to retry requests to busy
responders.  Remove unnecessary log messages.

Rename the flag is_irm to broadcast_channel_allocated to better reflect
its meaning.  Reset the flag earlier in fw_core_handle_bus_reset.

Pass the generation down as a call parameter; that way generation can't
be newer than card->broadcast_channel_allocated and device->node_id.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

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

type
    function_name(parameters);

is nice to look at but was not used consistently.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

So far it is only taken in non-atomic contexts.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

This adds a client_list_lock, which only protects the device's
client_list, so that future versions of the driver can call code that
takes the card->lock while holding the client_list_lock.  Adding this
lock is much simpler than adding __ versions of all the functions that
the future version may need.  The one ordering issue is to make sure
code never takes the client_list_lock with card->lock held.  Since
client_list_lock is only used in three places, that isn't hard.
Signed-off-by: NJay Fenlason <fenlason@redhat.com>

Update fill_bus_reset_event() accordingly.  Include linux/spinlock.h.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

There are situations when nodes vanish from the bus and come back
quickly thereafter:
  - When certain bus-powered hubs are plugged in,
  - when certain devices are plugged into 6-port hubs,
  - when certain disk enclosures are switched from self-power to bus
    power or vice versa and break the daisy chain during the transition,
  - when the user plugs a cable out and quickly plugs it back in, e.g.
    to reorder a daisy chain (works on Mac OS X if done quickly enough),
  - when certain hubs temporarily malfunction during high bus traffic.

Until now, firewire-core reported affected nodes as lost to the
highlevel drivers (firewire-sbp2 and userspace drivers).  We now delay
the destruction of device representations until after at least two
seconds after the last bus reset.  If a "new" device is detected in this
period whose bus information block and root directory header match that
of a device which is pending for deletion, we resurrect that device and
send update calls to highlevel drivers.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

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

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

When a device changes its configuration ROM, it announces this with a
bus reset.  firewire-core has to check which node initiated a bus reset
and whether any unit directories went away or were added on this node.

Tested with an IOI FWB-IDE01AB which has its link-on bit set if bus
power is available but does not respond to ROM read requests if self
power is off.  This implements
  - recognition of the units if self power is switched on after fw-core
    gave up the initial attempt to read the config ROM,
  - shutdown of the units when self power is switched off.

Also tested with a second PC running Linux/ieee1394.  When the eth1394
driver is inserted and removed on that node, fw-core now notices the
addition and removal of the IPv4 unit on the ieee1394 node.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Add wrappers for getting and putting a unit.
Remove some line breaks.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NJarod Wilson <jwilson@redhat.com>

"modprobe firewire-ohci; sleep .1; modprobe -r firewire-ohci" used to
result in crashes like this:

    BUG: unable to handle kernel paging request at ffffffff8807b455
    IP: [<ffffffff8807b455>]
    PGD 203067 PUD 207063 PMD 7c170067 PTE 0
    Oops: 0010 [1] PREEMPT SMP
    CPU 0
    Modules linked in: i915 drm cpufreq_ondemand acpi_cpufreq freq_table applesmc input_polldev led_class coretemp hwmon eeprom snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss button thermal processor sg snd_hda_intel snd_pcm snd_timer snd snd_page_alloc sky2 i2c_i801 rtc [last unloaded: crc_itu_t]
    Pid: 9, comm: events/0 Not tainted 2.6.25-rc2 #3
    RIP: 0010:[<ffffffff8807b455>]  [<ffffffff8807b455>]
    RSP: 0018:ffff81007dcdde88  EFLAGS: 00010246
    RAX: ffff81007dc95040 RBX: ffff81007dee5390 RCX: 0000000000005e13
    RDX: 0000000000008c8b RSI: 0000000000000001 RDI: ffff81007dee5388
    RBP: ffff81007dc5eb40 R08: 0000000000000002 R09: ffffffff8022d05c
    R10: ffffffff8023b34c R11: ffffffff8041a353 R12: ffff81007dee5388
    R13: ffffffff8807b455 R14: ffffffff80593bc0 R15: 0000000000000000
    FS:  0000000000000000(0000) GS:ffffffff8055a000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
    CR2: ffffffff8807b455 CR3: 0000000000201000 CR4: 00000000000006e0
    DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
    DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
    Process events/0 (pid: 9, threadinfo ffff81007dcdc000, task ffff81007dc95040)
    Stack:  ffffffff8023b396 ffffffff88082524 0000000000000000 ffffffff8807d9ae
    ffff81007dc5eb40 ffff81007dc9dce0 ffff81007dc5eb40 ffff81007dc5eb80
    ffff81007dc9dce0 ffffffffffffffff ffffffff8023be87 0000000000000000
    Call Trace:
    [<ffffffff8023b396>] ? run_workqueue+0xdf/0x1df
    [<ffffffff8023be87>] ? worker_thread+0xd8/0xe3
    [<ffffffff8023e917>] ? autoremove_wake_function+0x0/0x2e
    [<ffffffff8023bdaf>] ? worker_thread+0x0/0xe3
    [<ffffffff8023e813>] ? kthread+0x47/0x74
    [<ffffffff804198e0>] ? trace_hardirqs_on_thunk+0x35/0x3a
    [<ffffffff8020c008>] ? child_rip+0xa/0x12
    [<ffffffff8020b6e3>] ? restore_args+0x0/0x3d
    [<ffffffff8023e68a>] ? kthreadd+0x14c/0x171
    [<ffffffff8023e68a>] ? kthreadd+0x14c/0x171
    [<ffffffff8023e7cc>] ? kthread+0x0/0x74
    [<ffffffff8020bffe>] ? child_rip+0x0/0x12

    Code:  Bad RIP value.
    RIP  [<ffffffff8807b455>]
    RSP <ffff81007dcdde88>
    CR2: ffffffff8807b455
    ---[ end trace c7366c6657fe5bed ]---

Note that this crash happened _after_ firewire-core was unloaded.  The
shared workqueue tried to run firewire-core's device initialization jobs
or similar jobs.

The fix makes sure that firewire-ohci and hence firewire-core is not
unloaded before all device shutdown jobs have been completed.  This is
determined by the count of device initializations minus device releases.

Also skip useless retries in the node initialization job if the node is
to be shut down.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NJarod Wilson <jwilson@redhat.com>

There is a race between shutdown and creation of devices:  fw-core may
attempt to add a device with the same name of an already existing
device.  http://bugzilla.kernel.org/show_bug.cgi?id=9828

Impact of the bug:  Happens rarely (when shutdown of a device coincides
with creation of another), forces the user to unplug and replug the new
device to get it working.

The fix is obvious:  Free the minor number *after* instead of *before*
device_unregister().  This requires to take an additional reference of
the fw_device as long as the IDR tree points to it.

And while we are at it, we fix an additional race condition:
fw_device_op_open() took its reference of the fw_device a little bit too
late, hence was in danger to access an already invalid fw_device.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

fw_device.node_id and fw_device.generation are accessed without mutexes.
We have to ensure that all readers will get to see node_id updates
before generation updates.

Fixes an inability to recognize devices after "giving up on config rom",
https://bugzilla.redhat.com/show_bug.cgi?id=429950Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Reviewed by Nick Piggin <nickpiggin@yahoo.com.au>.

Verified to fix 'giving up on config rom' issues on multiple system and
drive combinations that were previously affected.
Signed-off-by: NJarod Wilson <jwilson@redhat.com>
Signed-off-by: NKristian Høgsberg <krh@redhat.com>

Fixes "New firewire stack only recognizing half of a chain of drives",
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=242254Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Use a speed probe to determine the speed over 1394b buses and of nodes
which report a link speed less than their PHY speed.

Log the effective maximum speed of newly created nodes in dmesg.

Also, read the config ROM (except bus info block) at the maximum speed
rather than S100.  This isn't a real optimization though because we
still only use quadlet read requests for the entire ROM.

The patch also adds support for S1600 and S3200, although such hardware
does not exist yet.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NKristian Høgsberg <krh@redhat.com>

The attribute /sys/bus/scsi/devices/*:*:*:*/ieee1394_id, as generated by
the old sbp2 driver, is typically used to create persistently named
links in /dev/disk/by-id.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NKristian Høgsberg <krh@redhat.com>

Drop filenames from file preamble, drop editor annotations and
use standard indent style for block comments.
Signed-off-by: NKristian Hoegsberg <krh@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (fixed typo)

We dynamically create an attribute group for the key present on the
device in hand and point device->group to it.  This way the device
core adds the sysfs attributes for us as the device is added.
Signed-off-by: NKristian Høgsberg <krh@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Puts a stray endian annotation down.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Drop the event list semaphore and only use the wait queue and the list
to synchronize queue access.  Break out of a poll or read whenever
the device is disconnected.
Signed-off-by: NKristian Høgsberg <krh@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The old mechanism kept a struct cdev for each fw device, but fops->release
would reference this struct after the device got freed in some cases.
Signed-off-by: NKristian Høgsberg <krh@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Signed-off-by: NKristian Høgsberg <krh@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

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

Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NKristian Høgsberg <krh@redhat.com>

Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NKristian Høgsberg <krh@redhat.com>

Instances of struct file_operations and struct fw_card_driver can be
qualified as "const".  Ditto with struct fw_descriptor.data, struct
fw_device_id, and predefined instances of struct fw_address_region,
at least in the current implementation.

Data qualified as const is placed into the .rodata section which won't
be mixed with dirty data.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Replace __fw_core_h by __fw_transaction_h to match the file name.
Add comments to the final #endif in header files.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Signed-off-by: NKristian Høgsberg <krh@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>