firewire: core: allocate workqueue to handle isochronous contexts in card

This commit adds a workqueue dedicated for isochronous context processing.

The workqueue is allocated per instance of fw_ca

firewire: core: allocate workqueue to handle isochronous contexts in card

This commit adds a workqueue dedicated for isochronous context processing.

The workqueue is allocated per instance of fw_card structure to satisfy the
following characteristics descending from 1394 OHCI specification:

In 1394 OHCI specification, memory pages are reserved to each isochronous
context dedicated to DMA transmission. It allows to operate these
per-context pages concurrently. Software can schedule hardware interrupt
for several isochronous context to the same cycle, thus WQ_UNBOUND is
specified. Additionally, it is sleepable to operate the content of pages,
thus WQ_BH is not used.

The isochronous context delivers the packets with time stamp, thus
WQ_HIGHPRI is specified for semi real-time data such as IEC 61883-1/6
protocol implemented by ALSA firewire stack. The isochronous context is not
used by the implementation of SCSI over IEEE1394 protocol (sbp2), thus
WQ_MEM_RECLAIM is not specified.

It is useful for users to adjust cpu affinity of the workqueue depending
on their work loads, thus WQ_SYS is specified to expose the attributes to
user space.

Tested-by: Edmund Raile <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Takashi Sakamoto <[email protected]>

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firewire: core: use guard macro to maintain properties of fw_card

The core functions uses spinlock in instance of fw_card structure to
protect concurrent access to properties in the instance.

This

firewire: core: use guard macro to maintain properties of fw_card

The core functions uses spinlock in instance of fw_card structure to
protect concurrent access to properties in the instance.

This commit uses guard macro to maintain the spinlock.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Takashi Sakamoto <[email protected]>

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firewire: core: use guard macro to maintain the list of card

The core function maintains registered cards by list. The concurrent
access to the list is protected by static mutex.

This commit uses g

firewire: core: use guard macro to maintain the list of card

The core function maintains registered cards by list. The concurrent
access to the list is protected by static mutex.

This commit uses guard macro to maintain the mutex.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Takashi Sakamoto <[email protected]>

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firewire: core: record card index in tracepoinrts events derived from bus_reset_arrange_template

The asynchronous transmission of phy packet is initiated on one of 1394
OHCI controller, however the

firewire: core: record card index in tracepoinrts events derived from bus_reset_arrange_template

The asynchronous transmission of phy packet is initiated on one of 1394
OHCI controller, however the existing tracepoints events has the lack of
data about it.

This commit adds card_index member into event structure to store the index
of host controller in use, and prints it.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Takashi Sakamoto <[email protected]>

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Revert "firewire: core: option to log bus reset initiation"

This reverts commit 6732491243045f5a7e1995b4be5f3c964b579ebd.

The former commit adds some alternative tracepoints events to replace the
r

Revert "firewire: core: option to log bus reset initiation"

This reverts commit 6732491243045f5a7e1995b4be5f3c964b579ebd.

The former commit adds some alternative tracepoints events to replace the
reverted kernel log messages.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Takashi Sakamoto <[email protected]>

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firewire: core: add tracepoints events for initiating bus reset

At a commit 673249124304 ("firewire: core: option to log bus reset
initiation"), some kernel log messages were added to trace initiati

firewire: core: add tracepoints events for initiating bus reset

At a commit 673249124304 ("firewire: core: option to log bus reset
initiation"), some kernel log messages were added to trace initiation of
bus reset. The kernel log messages are really helpful, while nowadays it
is not preferable just for debugging purpose. For the purpose, Linux
kernel tracepoints is more preferable.

This commit adds some alternative tracepoints events.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Takashi Sakamoto <[email protected]>

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firewire: core: option to log bus reset initiation

Add a debug parameter to firewire-core, analogous to the one in
firewire-ohci. When this is set to 1, log when we schedule, delay, or
initiate a bu

firewire: core: option to log bus reset initiation

Add a debug parameter to firewire-core, analogous to the one in
firewire-ohci. When this is set to 1, log when we schedule, delay, or
initiate a bus reset. Since FireWire bus resets can originate from any
node on the bus, specific logging of the resets we initiate provides
additional insight.

Signed-off-by: Adam Goldman <[email protected]>
Signed-off-by: Takashi Sakamoto <[email protected]>

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firewire: core: use long bus reset on gap count error

When resetting the bus after a gap count error, use a long rather than
short bus reset.

IEEE 1394-1995 uses only long bus resets. IEEE 1394a ad

firewire: core: use long bus reset on gap count error

When resetting the bus after a gap count error, use a long rather than
short bus reset.

IEEE 1394-1995 uses only long bus resets. IEEE 1394a adds the option of
short bus resets. When video or audio transmission is in progress and a
device is hot-plugged elsewhere on the bus, the resulting bus reset can
cause video frame drops or audio dropouts. Short bus resets reduce or
eliminate this problem. Accordingly, short bus resets are almost always
preferred.

However, on a mixed 1394/1394a bus, a short bus reset can trigger an
immediate additional bus reset. This double bus reset can be interpreted
differently by different nodes on the bus, resulting in an inconsistent gap
count after the bus reset. An inconsistent gap count will cause another bus
reset, leading to a neverending bus reset loop. This only happens for some
bus topologies, not for all mixed 1394/1394a buses.

By instead sending a long bus reset after a gap count inconsistency, we
avoid the doubled bus reset, restoring the bus to normal operation.

Signed-off-by: Adam Goldman <[email protected]>
Link: https://sourceforge.net/p/linux1394/mailman/message/58741624/
Signed-off-by: Takashi Sakamoto <[email protected]>

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firewire: core: send bus reset promptly on gap count error

If we are bus manager and the bus has inconsistent gap counts, send a
bus reset immediately instead of trying to read the root node's confi

firewire: core: send bus reset promptly on gap count error

If we are bus manager and the bus has inconsistent gap counts, send a
bus reset immediately instead of trying to read the root node's config
ROM first. Otherwise, we could spend a lot of time trying to read the
config ROM but never succeeding.

This eliminates a 50+ second delay before the FireWire bus is usable after
a newly connected device is powered on in certain circumstances.

The delay occurs if a gap count inconsistency occurs, we are not the root
node, and we become bus manager. One scenario that causes this is with a TI
XIO2213B OHCI, the first time a Sony DSR-25 is powered on after being
connected to the FireWire cable. In this configuration, the Linux box will
not receive the initial PHY configuration packet sent by the DSR-25 as IRM,
resulting in the DSR-25 having a gap count of 44 while the Linux box has a
gap count of 63.

FireWire devices have a gap count parameter, which is set to 63 on power-up
and can be changed with a PHY configuration packet. This determines the
duration of the subaction and arbitration gaps. For reliable communication,
all nodes on a FireWire bus must have the same gap count.

A node may have zero or more of the following roles: root node, bus manager
(BM), isochronous resource manager (IRM), and cycle master. Unless a root
node was forced with a PHY configuration packet, any node might become root
node after a bus reset. Only the root node can become cycle master. If the
root node is not cycle master capable, the BM or IRM should force a change
of root node.

After a bus reset, each node sends a self-ID packet, which contains its
current gap count. A single bus reset does not change the gap count, but
two bus resets in a row will set the gap count to 63. Because a consistent
gap count is required for reliable communication, IEEE 1394a-2000 requires
that the bus manager generate a bus reset if it detects that the gap count
is inconsistent.

When the gap count is inconsistent, build_tree() will notice this after the
self identification process. It will set card->gap_count to the invalid
value 0. If we become bus master, this will force bm_work() to send a bus
reset when it performs gap count optimization.

After a bus reset, there is no bus manager. We will almost always try to
become bus manager. Once we become bus manager, we will first determine
whether the root node is cycle master capable. Then, we will determine if
the gap count should be changed. If either the root node or the gap count
should be changed, we will generate a bus reset.

To determine if the root node is cycle master capable, we read its
configuration ROM. bm_work() will wait until we have finished trying to
read the configuration ROM.

However, an inconsistent gap count can make this take a long time.
read_config_rom() will read the first few quadlets from the config ROM. Due
to the gap count inconsistency, eventually one of the reads will time out.
When read_config_rom() fails, fw_device_init() calls it again until
MAX_RETRIES is reached. This takes 50+ seconds.

Once we give up trying to read the configuration ROM, bm_work() will wake
up, assume that the root node is not cycle master capable, and do a bus
reset. Hopefully, this will resolve the gap count inconsistency.

This change makes bm_work() check for an inconsistent gap count before
waiting for the root node's configuration ROM. If the gap count is
inconsistent, bm_work() will immediately do a bus reset. This eliminates
the 50+ second delay and rapidly brings the bus to a working state.

I considered that if the gap count is inconsistent, a PHY configuration
packet might not be successful, so it could be desirable to skip the PHY
configuration packet before the bus reset in this case. However, IEEE
1394a-2000 and IEEE 1394-2008 say that the bus manager may transmit a PHY
configuration packet before a bus reset when correcting a gap count error.
Since the standard endorses this, I decided it's safe to retain the PHY
configuration packet transmission.

Normally, after a topology change, we will reset the bus a maximum of 5
times to change the root node and perform gap count optimization. However,
if there is a gap count inconsistency, we must always generate a bus reset.
Otherwise the gap count inconsistency will persist and communication will
be unreliable. For that reason, if there is a gap count inconstency, we
generate a bus reset even if we already reached the 5 reset limit.

Signed-off-by: Adam Goldman <[email protected]>
Reference: https://sourceforge.net/p/linux1394/mailman/message/58727806/
Signed-off-by: Takashi Sakamoto <[email protected]>

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firewire: core: extend card->lock in fw_core_handle_bus_reset

card->local_node and card->bm_retries are both always accessed under
card->lock.
fw_core_handle_bus_reset has a check whose condition de

firewire: core: extend card->lock in fw_core_handle_bus_reset

card->local_node and card->bm_retries are both always accessed under
card->lock.
fw_core_handle_bus_reset has a check whose condition depends on
card->local_node and whose body writes to card->bm_retries.
Both of these accesses are not under card->lock. Move the lock acquiring
of card->lock to before this check such that these accesses do happen
when card->lock is held.
fw_destroy_nodes is called inside the check.
Since fw_destroy_nodes already acquires card->lock inside its function
body, move this out to the callsites of fw_destroy_nodes.
Also add a comment to indicate which locking is necessary when calling
fw_destroy_nodes.

Cc: <[email protected]>
Signed-off-by: Niels Dossche <[email protected]>
Signed-off-by: Takashi Sakamoto <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Takashi Iwai <[email protected]>

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firewire: add kernel API to access CYCLE_TIME register

1394 OHCI specification defined Isochronous Cycle Timer Register to get
value of CYCLE_TIME register defined by IEEE 1394 for CSR architecture

firewire: add kernel API to access CYCLE_TIME register

1394 OHCI specification defined Isochronous Cycle Timer Register to get
value of CYCLE_TIME register defined by IEEE 1394 for CSR architecture
defined by ISO/IEC 13213. Unit driver can calculate packet time by
compute with the value of CYCLE_TIME and timeStamp field in descriptor
of each isochronous and asynchronous context. The resolution of CYCLE_TIME
is 49.576 MHz, while the one of timeStamp is 8,000 Hz.

Current implementation of Linux FireWire subsystem allows the driver to
get the value of CYCLE_TIMER CSR register by transaction service. The
transaction service has overhead in regard of access to MMIO register.

This commit adds kernel API for unit driver to access the register
directly.

Signed-off-by: Takashi Sakamoto <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Takashi Iwai <[email protected]>

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firewire: Add dummy read_csr/write_csr functions

(Hector Martin wrote)
This fixes segfaults when a card gets yanked off of the PCIe bus while
busy, e.g. with a userspace app trying to get the cycle

firewire: Add dummy read_csr/write_csr functions

(Hector Martin wrote)
This fixes segfaults when a card gets yanked off of the PCIe bus while
busy, e.g. with a userspace app trying to get the cycle time:

[8638860.994310] Call Trace:
[8638860.994313] ioctl_get_cycle_timer2+0x4f/0xd0 [firewire_core]
[8638860.994323] fw_device_op_ioctl+0xae/0x150 [firewire_core]
[8638860.994328] __x64_sys_ioctl+0x7d/0xb0
[8638860.994332] do_syscall_64+0x45/0x80
[8638860.994337] entry_SYSCALL_64_after_hwframe+0x44/0xae

(Takashi Sakamoto wrote)
As long as reading commit 20802224298c ("firewire: core: add forgotten
dummy driver methods, remove unused ones"), three functions are not
implemeted in dummy driver for reason; .read_csr, .write_csr, and
.set_config_rom.

In core of Linux FireWire subsystem, the callback of .set_config_rom is
under acquisition of mutual exclusive for local list of card. The
acquision is also done in process for removal of card, therefore it's
safe for missing implementation of .set_config_rom.

On the other hand, no lock primitive accompanies any call of .read_csr and
.write_csr. For userspace client, check of node shutdown is done in the
beginning of dispatch of ioctl request, while node shifts to shutdown
state in workqueue context enough after card shifts to dummy driver. It's
probable that these two functions are called for the dummy driver by the
code of userspace client. In-kernel unit driver has similar situation.
It's better to add implementation of the two functions for dummy driver.

Signed-off-by: Hector Martin <[email protected]>
Signed-off-by: Takashi Sakamoto <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Takashi Iwai <[email protected]>

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of th

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not write to the free software foundation inc
59 temple place suite 330 boston ma 02111 1307 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Allison Randal <[email protected]>
Reviewed-by: Richard Fontana <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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firewire: Move fw_card kref functions into linux/firewire.h

When writing a firewire driver that doesn't deal with struct fw_device
objects (e.g. it only publishes FireWire units and doesn't subscrib

firewire: Move fw_card kref functions into linux/firewire.h

When writing a firewire driver that doesn't deal with struct fw_device
objects (e.g. it only publishes FireWire units and doesn't subscribe to
them), you likely need to keep referenced to struct fw_card objects so
that you can send messages to other nodes. This patch moves
fw_card_put(), fw_card_get() and fw_card_release() into the public
include/linux/firewire.h header instead of drivers/firewire/core.h, and
adds EXPORT_SYMBOL_GPL(fw_card_release).

The firewire-sbp-target module requires these so it can keep a reference
to the fw_card object in order that it can fetch ORBs to execute and
read/write related data and status information.

Signed-off-by: Chris Boot <[email protected]>
Acked-by: Stefan Richter <[email protected]>
Cc: Clemens Ladisch <[email protected]>
Signed-off-by: Nicholas Bellinger <[email protected]>

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firewire: core: log error in case of failed bus manager lock

If the lock access to the bus manager register fails, also log the
actual error that caused it to fail.

Signed-off-by: Clemens Ladisch <

firewire: core: log error in case of failed bus manager lock

If the lock access to the bus manager register fails, also log the
actual error that caused it to fail.

Signed-off-by: Clemens Ladisch <[email protected]>
Signed-off-by: Stefan Richter <[email protected]>

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firewire: allow explicit flushing of iso packet completions

Extend the kernel and userspace APIs to allow reporting all currently
completed isochronous packets, even if the next interrupt packet has

firewire: allow explicit flushing of iso packet completions

Extend the kernel and userspace APIs to allow reporting all currently
completed isochronous packets, even if the next interrupt packet has not
yet been reached. This is required to determine the status of the
packets at the end of a paused or stopped stream, and useful for more
precise synchronization of audio streams.

Signed-off-by: Clemens Ladisch <[email protected]>
Signed-off-by: Stefan Richter <[email protected]>

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firewire: core: prefix log messages with card name

Associate all log messages from firewire-core with the respective card
because some people have more than one card. E.g.
firewire_ohci 0000:04

firewire: core: prefix log messages with card name

Associate all log messages from firewire-core with the respective card
because some people have more than one card. E.g.
firewire_ohci 0000:04:00.0: added OHCI v1.10 device as card 0, 8 IR + 8 IT contexts, quirks 0x0
firewire_ohci 0000:05:00.0: added OHCI v1.10 device as card 1, 8 IR + 8 IT contexts, quirks 0x0
firewire_core: created device fw0: GUID 0814438400000389, S800
firewire_core: phy config: new root=ffc1, gap_count=5
firewire_core: created device fw1: GUID 0814438400000388, S800
firewire_core: created device fw2: GUID 0001d202e06800d1, S800
turns into
firewire_ohci 0000:04:00.0: added OHCI v1.10 device as card 0, 8 IR + 8 IT contexts, quirks 0x0
firewire_ohci 0000:05:00.0: added OHCI v1.10 device as card 1, 8 IR + 8 IT contexts, quirks 0x0
firewire_core 0000:04:00.0: created device fw0: GUID 0814438400000389, S800
firewire_core 0000:04:00.0: phy config: new root=ffc1, gap_count=5
firewire_core 0000:05:00.0: created device fw1: GUID 0814438400000388, S800
firewire_core 0000:04:00.0: created device fw2: GUID 0001d202e06800d1, S800

This increases the module size slightly; to keep this in check, turn the
former printk wrapper macros into functions. Their implementation is
largely copied from driver core's dev_printk counterparts.

Signed-off-by: Stefan Richter <[email protected]>

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atomic: use <linux/atomic.h>

This allows us to move duplicated code in <asm/atomic.h>
(atomic_inc_not_zero() for now) to <linux/atomic.h>

Signed-off-by: Arun Sharma <[email protected]>
Reviewed-by: Er

atomic: use <linux/atomic.h>

This allows us to move duplicated code in <asm/atomic.h>
(atomic_inc_not_zero() for now) to <linux/atomic.h>

Signed-off-by: Arun Sharma <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: David Miller <[email protected]>
Cc: Eric Dumazet <[email protected]>
Acked-by: Mike Frysinger <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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firewire: sbp2: parallelize login, reconnect, logout

The struct sbp2_logical_unit.work items can all be executed in parallel
but are not reentrant. Furthermore, reconnect or re-login work must be
e

firewire: sbp2: parallelize login, reconnect, logout

The struct sbp2_logical_unit.work items can all be executed in parallel
but are not reentrant. Furthermore, reconnect or re-login work must be
executed in a WQ_MEM_RECLAIM workqueue.

Hence replace the old single-threaded firewire-sbp2 workqueue by a
concurrency-managed but non-reentrant workqueue with rescuer.
firewire-core already maintains one, hence use this one.

In earlier versions of this change, I observed occasional failures of
parallel INQUIRY to an Initio INIC-2430 FireWire 800 to dual IDE bridge.
More testing indicates that parallel INQUIRY is not actually a problem,
but too quick successions of logout and login + INQUIRY, e.g. a quick
sequence of cable plugout and plugin, can result in failed INQUIRY.
This does not seem to be something that should or could be addressed by
serialization.

Another dual-LU device to which I currently have access to, an
OXUF924DSB FireWire 800 to dual SATA bridge with firmware from MacPower,
has been successfully tested with this too.

This change is beneficial to environments with two or more FireWire
storage devices, especially if they are located on the same bus.
Management tasks that should be performed as soon and as quickly as
possible, especially reconnect, are no longer held up by tasks on other
devices that may take a long time, especially login with INQUIRY and sd
or sr driver probe.

Signed-off-by: Stefan Richter <[email protected]>

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firewire: core: use non-reentrant workqueue with rescuer

firewire-core manages the following types of work items:

fw_card.br_work:
- resets the bus on a card and possibly sends a PHY packet befor

firewire: core: use non-reentrant workqueue with rescuer

firewire-core manages the following types of work items:

fw_card.br_work:
- resets the bus on a card and possibly sends a PHY packet before that
- does not sleep for long or not at all
- is scheduled via fw_schedule_bus_reset() by
- firewire-ohci's pci_probe method
- firewire-ohci's set_config_rom method, called by kernelspace
protocol drivers and userspace drivers which add/remove
Configuration ROM descriptors
- userspace drivers which use the bus reset ioctl
- itself if the last reset happened less than 2 seconds ago

fw_card.bm_work:
- performs bus management duties
- usually does not (but may in corner cases) sleep for long
- is scheduled via fw_schedule_bm_work() by
- firewire-ohci's self-ID-complete IRQ handler tasklet
- firewire-core's fw_device.work instances whenever the root node
device was (successfully or unsuccessfully) discovered,
refreshed, or rediscovered
- itself in case of resource allocation failures or in order to
obey the 125ms bus manager arbitration interval

fw_device.work:
- performs node probe, update, shutdown, revival, removal; including
kernel driver probe, update, shutdown and bus reset notification to
userspace drivers
- usually sleeps moderately long, in corner cases very long
- is scheduled by
- firewire-ohci's self-ID-complete IRQ handler tasklet via the
core's fw_node_event
- firewire-ohci's pci_remove method via core's fw_destroy_nodes/
fw_node_event
- itself during retries, e.g. while a node is powering up

iso_resource.work:
- accesses registers at the Isochronous Resource Manager node
- usually does not (but may in corner cases) sleep for long
- is scheduled via schedule_iso_resource() by
- the owning userspace driver at addition and removal of the
resource
- firewire-core's fw_device.work instances after bus reset
- itself in case of resource allocation if necessary to obey the
1000ms reallocation period after bus reset

fw_card.br_work instances should not, and instances of the others must
not, be executed in parallel by multiple CPUs -- but were not protected
against that. Hence allocate a non-reentrant workqueue for them.

fw_device.work may be used in the memory reclaim path in case of SBP-2
device updates. Hence we need a workqueue with rescuer and cannot use
system_nrt_wq.

Signed-off-by: Stefan Richter <[email protected]>
Reviewed-by: Tejun Heo <[email protected]>

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firewire: optimize iso queueing by setting wake only after the last packet

When queueing iso packets, the run time is dominated by the two
MMIO accesses that set the DMA context's wake bit. Because

firewire: optimize iso queueing by setting wake only after the last packet

When queueing iso packets, the run time is dominated by the two
MMIO accesses that set the DMA context's wake bit. Because most
drivers submit packets in batches, we can save much time by
removing all but the last wakeup.

The internal kernel API is changed to require a call to
fw_iso_context_queue_flush() after a batch of queued packets.
The user space API does not change, so one call to
FW_CDEV_IOC_QUEUE_ISO must specify multiple packets to take
advantage of this optimization.

In my measurements, this patch reduces the time needed to queue
fifty skip packets from userspace to one sixth on a 2.5 GHz CPU,
or to one third at 800 MHz.

Signed-off-by: Clemens Ladisch <[email protected]>
Signed-off-by: Stefan Richter <[email protected]>

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firewire: octlet AT payloads can be stack-allocated

We do not need slab allocations anymore in order to satisfy
streaming DMA mapping constraints, thanks to commit da28947e7e36
"firewire: ohci: avoi

firewire: octlet AT payloads can be stack-allocated

We do not need slab allocations anymore in order to satisfy
streaming DMA mapping constraints, thanks to commit da28947e7e36
"firewire: ohci: avoid separate DMA mapping for small AT payloads".

(Besides, the slab-allocated buffers that firewire-core, firewire-sbp2,
and firedtv used to provide for 8-byte write and lock requests were
still not fully portable since they crossed cacheline boundaries or
shared a cacheline with unrelated CPU-accessed data. snd-firewire-lib
got this aspect right by using an extra kmalloc/ kfree just for the
8-byte transaction buffer.)

This change replaces kmalloc'ed lock transaction scratch buffers in
firewire-core, firedtv, and snd-firewire-lib by local stack allocations.
Perhaps the most notable result of the change is simpler locking because
there is no need to serialize usages of preallocated per-device buffers
anymore. Also, allocations and deallocations are simpler.

Signed-off-by: Stefan Richter <[email protected]>
Acked-by: Clemens Ladisch <[email protected]>

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firewire: core: increase default SPLIT_TIMEOUT value

The SPLIT_TIMEOUT mechanism is intended to detect requests that somehow
got lost. However, when the timeout value is too low, transactions that

firewire: core: increase default SPLIT_TIMEOUT value

The SPLIT_TIMEOUT mechanism is intended to detect requests that somehow
got lost. However, when the timeout value is too low, transactions that
could have been completed successfully will be cancelled. Furthermore,
there are chips whose firmwares ignore the configured split timeout and
send late split response; known examples are the DM1x00 (BeBoB), TCD22x0
(DICE), and some OXUF936QSE firmwares.

This patch changes the default timeout to two seconds, which happens to
be the default on other OSes, too.

Actual lost requests are extremely rare, so there should be no practical
downside to increasing the split timeout even on devices that work
correctly.

Signed-off-by: Clemens Ladisch <[email protected]>
Signed-off-by: Stefan Richter <[email protected]>

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firewire: core: fix card->reset_jiffies overflow

On a 32-bit machine with, e.g., HZ=1000, jiffies will overflow after
about 50 days, so if there are between 25 and 50 days between bus
resets, the ca

firewire: core: fix card->reset_jiffies overflow

On a 32-bit machine with, e.g., HZ=1000, jiffies will overflow after
about 50 days, so if there are between 25 and 50 days between bus
resets, the card->reset_jiffies comparisons can get wrong results.

To fix this, ensure that this timestamp always uses 64 bits.

Signed-off-by: Clemens Ladisch <[email protected]>
Signed-off-by: "Stefan Richter" <[email protected]>

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firewire: core: fix unstable I/O with Canon camcorder

Regression since commit 10389536742c, "firewire: core: check for 1394a
compliant IRM, fix inaccessibility of Sony camcorder":

The camcorder Can

firewire: core: fix unstable I/O with Canon camcorder

Regression since commit 10389536742c, "firewire: core: check for 1394a
compliant IRM, fix inaccessibility of Sony camcorder":

The camcorder Canon MV5i generates lots of bus resets when asynchronous
requests are sent to it (e.g. Config ROM read requests or FCP Command
write requests) if the camcorder is not root node. This causes drop-
outs in videos or makes the camcorder entirely inaccessible.
https://bugzilla.redhat.com/show_bug.cgi?id=633260

Fix this by allowing any Canon device, even if it is a pre-1394a IRM
like MV5i are, to remain root node (if it is at least Cycle Master
capable). With the FireWire controller cards that I tested, MV5i always
becomes root node when plugged in and left to its own devices.

Reported-by: Ralf Lange
Signed-off-by: Stefan Richter <[email protected]>
Cc: <[email protected]> # 2.6.32.y and newer

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