The bitmask for enabling the BatTemp pull-up was wrong and
is corrected. The name is also changed to be inline with
the AB8500 register description
Signed-off-by: Johan Palsson <johan.palsson@stericsson.com>
Reviewed-by: Mattias Wallin <mattias.wallin@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
In AB8500 3.0 the pull-up supplying the NTC must be manually activated.
Add enumerators to chip version detection logic.
Signed-off-by: Kalle Komierowski <karl.komierowski@stericsson.com>
Reviewed-by: Johan Palsson <johan.palsson@stericsson.com>
Reviewed-by: Daniel Willerud <daniel.willerud@stericsson.com>
Reviewed-by: Jonas Aberg <jonas.aberg@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Since functionality in MFD cells may need to be adjusted according to
chip revision, let's enumerate them and keep track of them.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Fixing the error condition check in twl4030 remove script function.
Due to some typo in commit ID: 11a441ce82
Signed-off-by: Lesly A M <leslyam@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
The charger fault IRQs from the twl will in future patches be handled
by a seperate IRQ handler in the charger driver than the general charger
IRQ. Give them different IRQ numbers now to allow the charger driver to
be merged in the future.
Signed-off-by: Graeme Gregory <gg@slimlogic.co.uk>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Phoenix Lite is based on the twl6030 family of PMICs. It has mostly the
same feature set of twl6030 but with small changes. The codec block has
also been removed. It also has a new charger block and new features in
its ADC block. VUSB handling also differs.
Signed-off-by: Graeme Gregory <gg@slimlogic.co.uk>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Avoid to use constraint name in regulator driver. So use regulator id is used
instead in platform driver.
Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Cc: Liam Girdwood <lrg@slimlogic.co.uk>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Since regulator[0] is always checking in mfd driver, it results in
registration failure without regulator[0].
Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
i2c_client parameter isn't used in some functions. Just remove it.
Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Maybe multiple PMIC devices are installed into one board. Static variable
can only make driver logic mess. So remove these variable, and use
platform data from platform driver instead.
Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Force to enable i2c as power up/down sequence. Otherwise, SD/LDO can't
be enabled or disabled via accessing i2c bus.
Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Cc: Liam Girdwood <lrg@slimlogic.co.uk>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Avoid to get platform_data from parent device. Get it from mfd cell
device instead.
Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Acked-by: Anton Vorontsov <cbou@mail.ru>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
In the current code, every time we set a TPS6586x GPIO pin,
the tps6586x_gpio_set function is resetting all other GPIO pins.
We need to update the right GPIOxOUT bit of the GPIOSET2 register instead
of overriding the full value.
Tested by setting sequentially GPIO2 and GPIO3 and verifying the
pins voltage.
Change-Id: I560edde146c5425cce37432c4ee91569eea5adcf
Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
Acked-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Add support for the irq controller in Qualcomm 8xxx pmic. The 8xxx
interrupt controller provides control for gpio and mpp configured as
interrupts in addition to other subdevice interrupts. The interrupt
controller also provides a way to read the real time status of an
interrupt. This real time status is the only way one can get the
input values of gpio and mpp lines.
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Add support for the Qualcomm PM8921 PMIC chip. The core driver
will communicate with the PMIC chip via the MSM SSBI bus.
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
PCF50633_ADC and PCF50633_GPIO depends on MFD_PCF50633.
Thus group NXP PCF50633* drivers together.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Group TPSxxxxx power management chips together and sort in alphabetical order.
This change makes it easier for users to find config options.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Added API to get the TWL5030 Si version from the IDCODE register.
It is used for enabling the workaround for TWL erratum 27.
Signed-off-by: Lesly A M <leslyam@ti.com>
Cc: Nishanth Menon <nm@ti.com>
Cc: David Derrick <dderrick@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Modifying the macro name Main_Ref to all caps(MAIN_REF).
Suggested by Nishanth Menon <nm@ti.com>
Signed-off-by: Lesly A M <leslyam@ti.com>
Cc: Nishanth Menon <nm@ti.com>
Cc: David Derrick <dderrick@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Correcting the if condition check for printing the warning,
if wakeup script is not updated before updating the sleep script.
Since the flag 'order' is set to '1' while updating the wakeup script
for P1P2, the condition checking for printing the warning should be
if(!order) (ie: print the warning if wakeup script is not updated before
updating the sleep script)
Signed-off-by: Lesly A M <leslyam@ti.com>
Cc: Nishanth Menon <nm@ti.com>
Cc: David Derrick <dderrick@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
WARNING: vmlinux.o(.devinit.text+0x6c4): Section mismatch in reference
from the function device_onkey_init() to the (unknown reference)
.init.data:(unknown)
The function __devinit device_onkey_init() references a (unknown reference)
__initdata (unknown).
If (unknown) is only used by device_onkey_init then annotate (unknown)
with a matching annotation.
It's caused by using __initdata on mfd cell resources. Replace __initdata
with __devinitdata.
Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
The fact that we can't actually raise any interrupts doesn't stop us
setting up the IRQs we're exporting. While this isn't actually going
to do anything it allows us to proceed further through device setup
during board bringup and avoids issues with the MFD core not letting
us suppress the configuration of IRQ resources.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Allow the GPIO mode of WM831x devices to be configured using platform data.
Users may provide a table of GPIO register values in gpio_defaults[]. In
order to allow 0 to be set explicitly out of range values are accepted and
masked off, with a WM831X_GPIO_CONFIGURE define provided to set an out of
range value.
This can be used to configure higher numbered GPIOs or override values set
in OTP for GPIOs configured using OTP.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
The last user was removed in the merge window.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Cell pointers are passed through device->mfd_cell and platform data
is passed through the MFD cell platform_data pointer.
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
With the addition of a platform device mfd_cell pointer, MFD drivers
can go back to passing platform data back to their sub drivers.
This allows for an mfd_cell->mfd_data removal and thus keep the
sub drivers MFD agnostic. This is mostly needed for non MFD aware
sub drivers.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
With the addition of a platform device mfd_cell pointer, MFD drivers
can go back to passing platform data back to their sub drivers.
This allows for an mfd_cell->mfd_data removal and thus keep the
sub drivers MFD agnostic. This is mostly needed for non MFD aware
sub drivers.
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
With the addition of a platform device mfd_cell pointer, MFD drivers
can go back to passing platform back to their sub drivers.
This allows for an mfd_cell->mfd_data removal and thus keep the
sub drivers MFD agnostic. This is mostly needed for non MFD aware
sub drivers.
Cc: Miguel Aguilar <miguel.aguilar@ridgerun.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
With the addition of a platform device mfd_cell pointer, MFD drivers
can go back to passing platform back to their sub drivers.
This allows for an mfd_cell->mfd_data removal and thus keep the
sub drivers MFD agnostic. This is mostly needed for non MFD aware
sub drivers.
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Liam Girdwood <lrg@slimlogic.co.uk>
Cc: Richard Purdie <rpurdie@rpsys.net>
Acked-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
With the addition of a platform device mfd_cell pointer, MFD drivers
can go back to passing platform data back to their sub drivers.
This allows for an mfd_cell->mfd_data removal and thus keep the
sub drivers MFD agnostic. This is mostly needed for non MFD aware
sub drivers.
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Liam Girdwood <lrg@slimlogic.co.uk>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
With the addition of a platform device mfd_cell pointer, MFD drivers
can go back to passing platform data back to their sub drivers.
This allows for an mfd_cell->mfd_data removal and thus keep the
sub drivers MFD agnostic. This is mostly needed for non MFD aware
sub drivers.
Cc: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Liam Girdwood <lrg@slimlogic.co.uk>
Cc: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
With the addition of a platform device mfd_cell pointer, MFD drivers
can go back to passing platform data back to their sub drivers.
This allows for an mfd_cell->mfd_data removal and thus keep the
sub drivers MFD agnostic. This is mostly needed for non MFD aware
sub drivers.
Cc: Ira W. Snyder <iws@ovro.caltech.edu>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
With the addition of a platform device mfd_cell pointer, MFD drivers
can go back to passing platform data back to their sub drivers.
This allows for an mfd_cell->mfd_data removal and thus keep the
sub drivers MFD agnostic. This is mostly needed for non MFD aware
sub drivers.
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Liam Girdwood <lrg@slimlogic.co.uk>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
With the addition of a platform device mfd_cell pointer, MFD drivers
can go back to passing platform data back to their sub drivers.
This allows for an mfd_cell->mfd_data removal and thus keep the
sub drivers MFD agnostic. This is mostly needed for non MFD aware
sub drivers.
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
With the addition of a device platform mfd_cell pointer, MFD drivers
can go back to passing platform data back to their sub drivers.
This allows for an mfd_cell->mfd_data removal and thus keep the
sub drivers MFD agnostic. This is mostly needed for non MFD aware
sub drivers.
Acked-by: Richard Röjfors <richard.rojfors@pelagicore.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
With the addition of the platform device mfd_cell pointer, we can now
cleanly pass the sub device drivers platform data pointers through the
regular device platform_data one, and get rid of mfd_get_data().
Cc: Ian Molton <spyro@f2s.com>
Cc: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Acked-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
With the addition of the platform device mfd_cell pointer, we can now
cleanly pass the sub device drivers platform data pointers through the
regular device platform_data one, and get rid of mfd_get_data().
Cc: Ian Molton <spyro@f2s.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Acked-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
With the addition of a platform device mfd_cell pointer, MFD drivers
can go back to passing platform data back to their sub drivers.
This allows for an mfd_cell->mfd_data removal and thus keep the
sub drivers MFD agnostic. This is mostly needed for non MFD aware
sub drivers.
Cc: Matti Aaltonen <matti.j.aaltonen@nokia.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
With the addition of the platform device mfd_cell pointer, we can now
cleanly pass the sub device drivers platform data pointers through the
regular device platform_data one, and get rid of mfd_get_data().
Cc: Matt Reimer <mreimer@vpop.net>
Cc: Philipp Zabel <philipp.zabel@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
With the addition of the platform device mfd_cell pointer, we can now
cleanly pass the sub device drivers platform data pointers through the
regular device platform_data one, and get rid of mfd_get_data()
Cc: Ian Molton <spyro@f2s.com>
Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Philipp Zabel <philipp.zabel@gmail.com>
Acked-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
With the addition of a platform device mfd_cell pointer, MFD drivers
can go back to passing platform data back to their sub drivers.
This allows for an mfd_cell->mfd_data removal and thus keep the sub drivers
MFD agnostic. This is mostly needed for non MFD aware sub drivers.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
With the addition of a platform device mfd_cell pointer, MFD drivers
can go back to passing platform data back to their sub drivers.
This allows for an mfd_cell->mfd_data removal and thus keep the sub drivers
MFD agnostic. This is mostly needed for non MFD aware sub drivers.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Now that we have a way to pass MFD cells down to the sub drivers,
we can gradually get rid of mfd_data by putting the platform pointer
back in place.
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (61 commits)
jbd2: Add MAINTAINERS entry
jbd2: fix a potential leak of a journal_head on an error path
ext4: teach ext4_ext_split to calculate extents efficiently
ext4: Convert ext4 to new truncate calling convention
ext4: do not normalize block requests from fallocate()
ext4: enable "punch hole" functionality
ext4: add "punch hole" flag to ext4_map_blocks()
ext4: punch out extents
ext4: add new function ext4_block_zero_page_range()
ext4: add flag to ext4_has_free_blocks
ext4: reserve inodes and feature code for 'quota' feature
ext4: add support for multiple mount protection
ext4: ensure f_bfree returned by ext4_statfs() is non-negative
ext4: protect bb_first_free in ext4_trim_all_free() with group lock
ext4: only load buddy bitmap in ext4_trim_fs() when it is needed
jbd2: Fix comment to match the code in jbd2__journal_start()
ext4: fix waiting and sending of a barrier in ext4_sync_file()
jbd2: Add function jbd2_trans_will_send_data_barrier()
jbd2: fix sending of data flush on journal commit
ext4: fix ext4_ext_fiemap_cb() to handle blocks before request range correctly
...
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (25 commits)
cifs: remove unnecessary dentry_unhash on rmdir/rename_dir
ocfs2: remove unnecessary dentry_unhash on rmdir/rename_dir
exofs: remove unnecessary dentry_unhash on rmdir/rename_dir
nfs: remove unnecessary dentry_unhash on rmdir/rename_dir
ext2: remove unnecessary dentry_unhash on rmdir/rename_dir
ext3: remove unnecessary dentry_unhash on rmdir/rename_dir
ext4: remove unnecessary dentry_unhash on rmdir/rename_dir
btrfs: remove unnecessary dentry_unhash in rmdir/rename_dir
ceph: remove unnecessary dentry_unhash calls
vfs: clean up vfs_rename_other
vfs: clean up vfs_rename_dir
vfs: clean up vfs_rmdir
vfs: fix vfs_rename_dir for FS_RENAME_DOES_D_MOVE filesystems
libfs: drop unneeded dentry_unhash
vfs: update dentry_unhash() comment
vfs: push dentry_unhash on rename_dir into file systems
vfs: push dentry_unhash on rmdir into file systems
vfs: remove dget() from dentry_unhash()
vfs: dentry_unhash immediately prior to rmdir
vfs: Block mmapped writes while the fs is frozen
...
(Note: this was reverted, and is now being re-applied in pieces, with
this being the fifth and final piece. See below for the reason that
it is now felt to be safe to re-apply this.)
Commit d09b62d fixed grace-period synchronization, but left some smp_mb()
invocations in rcu_process_callbacks() that are no longer needed, but
sheer paranoia prevented them from being removed. This commit removes
them and provides a proof of correctness in their absence. It also adds
a memory barrier to rcu_report_qs_rsp() immediately before the update to
rsp->completed in order to handle the theoretical possibility that the
compiler or CPU might move massive quantities of code into a lock-based
critical section. This also proves that the sheer paranoia was not
entirely unjustified, at least from a theoretical point of view.
In addition, the old dyntick-idle synchronization depended on the fact
that grace periods were many milliseconds in duration, so that it could
be assumed that no dyntick-idle CPU could reorder a memory reference
across an entire grace period. Unfortunately for this design, the
addition of expedited grace periods breaks this assumption, which has
the unfortunate side-effect of requiring atomic operations in the
functions that track dyntick-idle state for RCU. (There is some hope
that the algorithms used in user-level RCU might be applied here, but
some work is required to handle the NMIs that user-space applications
can happily ignore. For the short term, better safe than sorry.)
This proof assumes that neither compiler nor CPU will allow a lock
acquisition and release to be reordered, as doing so can result in
deadlock. The proof is as follows:
1. A given CPU declares a quiescent state under the protection of
its leaf rcu_node's lock.
2. If there is more than one level of rcu_node hierarchy, the
last CPU to declare a quiescent state will also acquire the
->lock of the next rcu_node up in the hierarchy, but only
after releasing the lower level's lock. The acquisition of this
lock clearly cannot occur prior to the acquisition of the leaf
node's lock.
3. Step 2 repeats until we reach the root rcu_node structure.
Please note again that only one lock is held at a time through
this process. The acquisition of the root rcu_node's ->lock
must occur after the release of that of the leaf rcu_node.
4. At this point, we set the ->completed field in the rcu_state
structure in rcu_report_qs_rsp(). However, if the rcu_node
hierarchy contains only one rcu_node, then in theory the code
preceding the quiescent state could leak into the critical
section. We therefore precede the update of ->completed with a
memory barrier. All CPUs will therefore agree that any updates
preceding any report of a quiescent state will have happened
before the update of ->completed.
5. Regardless of whether a new grace period is needed, rcu_start_gp()
will propagate the new value of ->completed to all of the leaf
rcu_node structures, under the protection of each rcu_node's ->lock.
If a new grace period is needed immediately, this propagation
will occur in the same critical section that ->completed was
set in, but courtesy of the memory barrier in #4 above, is still
seen to follow any pre-quiescent-state activity.
6. When a given CPU invokes __rcu_process_gp_end(), it becomes
aware of the end of the old grace period and therefore makes
any RCU callbacks that were waiting on that grace period eligible
for invocation.
If this CPU is the same one that detected the end of the grace
period, and if there is but a single rcu_node in the hierarchy,
we will still be in the single critical section. In this case,
the memory barrier in step #4 guarantees that all callbacks will
be seen to execute after each CPU's quiescent state.
On the other hand, if this is a different CPU, it will acquire
the leaf rcu_node's ->lock, and will again be serialized after
each CPU's quiescent state for the old grace period.
On the strength of this proof, this commit therefore removes the memory
barriers from rcu_process_callbacks() and adds one to rcu_report_qs_rsp().
The effect is to reduce the number of memory barriers by one and to
reduce the frequency of execution from about once per scheduling tick
per CPU to once per grace period.
This was reverted do to hangs found during testing by Yinghai Lu and
Ingo Molnar. Frederic Weisbecker supplied Yinghai with tracing that
located the underlying problem, and Frederic also provided the fix.
The underlying problem was that the HARDIRQ_ENTER() macro from
lib/locking-selftest.c invoked irq_enter(), which in turn invokes
rcu_irq_enter(), but HARDIRQ_EXIT() invoked __irq_exit(), which
does not invoke rcu_irq_exit(). This situation resulted in calls
to rcu_irq_enter() that were not balanced by the required calls to
rcu_irq_exit(). Therefore, after these locking selftests completed,
RCU's dyntick-idle nesting count was a large number (for example,
72), which caused RCU to to conclude that the affected CPU was not in
dyntick-idle mode when in fact it was.
RCU would therefore incorrectly wait for this dyntick-idle CPU, resulting
in hangs.
In contrast, with Frederic's patch, which replaces the irq_enter()
in HARDIRQ_ENTER() with an __irq_enter(), these tests don't ever call
either rcu_irq_enter() or rcu_irq_exit(), which works because the CPU
running the test is already marked as not being in dyntick-idle mode.
This means that the rcu_irq_enter() and rcu_irq_exit() calls and RCU
then has no problem working out which CPUs are in dyntick-idle mode and
which are not.
The reason that the imbalance was not noticed before the barrier patch
was applied is that the old implementation of rcu_enter_nohz() ignored
the nesting depth. This could still result in delays, but much shorter
ones. Whenever there was a delay, RCU would IPI the CPU with the
unbalanced nesting level, which would eventually result in rcu_enter_nohz()
being called, which in turn would force RCU to see that the CPU was in
dyntick-idle mode.
The reason that very few people noticed the problem is that the mismatched
irq_enter() vs. __irq_exit() occured only when the kernel was built with
CONFIG_DEBUG_LOCKING_API_SELFTESTS.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
