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fw_priv->buf is accessed in both request_firmware_load() and
writing to sysfs file of 'loading' context, but not protected
by 'fw_lock' entirely. The patch makes sure that access on
'fw_priv->buf' is protected by the lock.
So fixes the double abort problem reported by nirinA raseliarison:
http://lkml.org/lkml/2013/6/14/188
Reported-and-tested-by: nirinA raseliarison <nirina.raseliarison@gmail.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable <stable@vger.kernel.org> # 3.9
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We want these fixes here too.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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If a device have sleep and idle states in addition to the
default state, look up these in the core and stash them in
the pinctrl state container.
Add accessor functions for pinctrl consumers to put the pins
into "default", "sleep" and "idle" states passing nothing but
the struct device * affected.
Solution suggested by Kevin Hilman, Mark Brown and Dmitry
Torokhov in response to a patch series from Hebbar
Gururaja.
Cc: Hebbar Gururaja <gururaja.hebbar@ti.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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It is common to access regmap registers at bit level, using
regmap_update_bits or regmap_read functions, however the end user has to
take care of a mask or shifting. This becomes overhead when such use
cases are high. Having a common function to do this is much convenient
and less error prone.
The idea of regmap_field is simple, regmap_field gives a logical
structure to bits of the regmap register, and the driver can use this
logical entity without the knowledge of the bit positions and masks all
over the code. This way code looks much neat and it need not handle the
masks, shifts every time it access the those entities.
With this new regmap_field_read/write apis the end user can setup a
regmap field using regmap_field_init and use the return regmap_field to
read write the register field without worrying about the masks or
shifts.
Also this apis will be useful for drivers which are based on regmaps,
like some clocks or pinctrls which can work on the regmap_fields
directly without having to worry about bit positions.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
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In converting the last remaining of_platform_driver (ibmebus) to a regular
platform driver, to_platform_driver is needed to replace
to_of_platform_driver.
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Grant Likely <grant.likely@linaro.org>
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This adds in a new message to the wakeup code which adds an
indication to the log that suspend was cancelled due to a wake event
occouring during the suspend sequence. It also adjusts the message
printed in suspend.c to reflect the potential that a suspend was
aborted, as opposed to a device failing to suspend.
Without these message adjustments one can end up with a kernel log
that says that a device failed to suspend with no actual device
suspend failures, which can be confusing to the log examiner.
Signed-off-by: Bernie Thompson <bhthompson@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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module reference doesn't cover direct loading path, so this patch
simply holds the module in the whole life time of request_firmware()
to fix the problem.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Looks no driver has the explict requirement for the two exported
API, just don't export them anymore.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Update the sysfs memory code to create/delete files at the time of device
and subsystem registration.
The current code creates files in the root memory directory explicitly through
the use of init_* routines. The files for each memory block are created and
deleted explicitly using the mem_[create|delete]_simple_file macros.
This patch creates attribute groups for the memory root files and files in
each memory block directory so that they are created and deleted implicitly
at subsys and device register and unregister time.
This did necessitate moving the register_memory() updating it to set the
dev.groups field.
Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The commit ddf1f0648e8c("firmware loader: fix build failure
with !CONFIG_FW_LOADER_USER_HELPER") introduces the below
warning:
drivers/base/firmware_class.c:921:13: warning:
'kill_requests_without_uevent' defined but not used [-Wunused-function]
So fix it by defining kill_requests_without_uevent() only if
CONFIG_PM_SLEEP is set.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This patch fixes one build failure which is introduced by the patch
below:
driver core: firmware loader: kill FW_ACTION_NOHOTPLUG requests
before suspend
When CONFIG_FW_LOADER_USER_HELPER is unset, kill_requests_without_uevent()
should be nop because no userspace loading is involved.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The "index" field of struct cpufreq_frequency_table was never an
index and isn't used at all by the cpufreq core. It only is useful
for cpufreq drivers for their internal purposes.
Many people nowadays blindly set it in ascending order with the
assumption that the core will use it, which is a mistake.
Rename it to "driver_data" as that's what its purpose is. All of its
users are updated accordingly.
[rjw: Changelog]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Ever since commit 45f035ab9b8f ("CONFIG_HOTPLUG should be always on"),
it has been basically impossible to build a kernel with CONFIG_HOTPLUG
turned off. Remove all the remaining references to it.
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Doug Thompson <dougthompson@xmission.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This patch kills the firmware loading requests of FW_ACTION_NOHOTPLUG
before suspend to avoid blocking suspend because there is no timeout
for these requests.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Generally there are only two drivers which don't need uevent to
handle firmware loading, so don't cache these firmwares during
suspend for these drivers since doing that may block firmware
loading forever.
Both the two drivers are involved in private firmware images, so
they don't hit in direct loading too.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Standardize the indentation, and switch the order of a couple
kerneldoc entries to match the parameter order. No functional change.
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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I found a lot of mistakes using struct platform_driver without owner
so I make a macro instead of the function platform_driver_register.
It can set owner in it, then guys don`t care about module owner again.
Signed-off-by: Libo Chen <libo.chen@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Move EXPORT_SYMBOL annotations so they follow immediately after the
closing function brace line.
Signed-off-by: Daniel Mack <zonque@gmail.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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When a system goes to reboot/shutdown, it tries to disable the
usermode helper via usermodehelper_disable(). This might be blocked
when a driver tries to load a firmware beforehand and it's stuck by
some reason. For example, dell_rbu driver loads the firmware in
non-hotplug mode and waits for user-space clearing the loading sysfs
flag. If user-space doesn't clear the flag, it waits forever, thus
blocks the reboot, too.
As a workaround, in this patch, the firmware class driver registers a
reboot notifier so that it can abort all pending f/w bufs before
issuing usermodehelper_disable().
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The "runtime idle" helper routine, rpm_idle(), currently ignores
return values from .runtime_idle() callbacks executed by it.
However, it turns out that many subsystems use
pm_generic_runtime_idle() which checks the return value of the
driver's callback and executes pm_runtime_suspend() for the device
unless that value is not 0. If that logic is moved to rpm_idle()
instead, pm_generic_runtime_idle() can be dropped and its users
will not need any .runtime_idle() callbacks any more.
Moreover, the PCI, SCSI, and SATA subsystems' .runtime_idle()
routines, pci_pm_runtime_idle(), scsi_runtime_idle(), and
ata_port_runtime_idle(), respectively, as well as a few drivers'
ones may be simplified if rpm_idle() calls rpm_suspend() after 0 has
been returned by the .runtime_idle() callback executed by it.
To reduce overall code bloat, make the changes described above.
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Kevin Hilman <khilman@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
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Currently all register maps with a cache need to provide a volatile
callback since the default is to assume all registers are volatile.
This is not sensible if we have a cache so change the default to be
fully cached if a cache is provided.
Signed-off-by: Mark Brown <broonie@linaro.org>
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This can be used for cache types for which syncing values one by one is
equally efficient as syncing a range, such as the flat cache.
Signed-off-by: Maarten ter Huurne <maarten@treewalker.org>
Signed-off-by: Mark Brown <broonie@linaro.org>
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Since offline_memory_block(mem) is functionally equivalent to
device_offline(&mem->dev), make the only caller of the former use
the latter instead and drop offline_memory_block() entirely.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
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As noted by Tang Chen, the last_online field in struct memory_block
introduced by commit 4960e05 (Driver core: Introduce offline/online
callbacks for memory blocks) is not really necessary, because
online_pages() restores the previous state if passed ONLINE_KEEP as
the last argument. Therefore, remove that field along with the code
referring to it.
References: http://marc.info/?l=linux-kernel&m=136919777305599&w=2
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Tang Chen <tangchen@cn.fujitsu.com>
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A node starting before the minimum register is no reason to reject it,
since its end could be in range. The check for the end already exists
two lines lower, so we can just remove the incorrect check.
Signed-off-by: Maarten ter Huurne <maarten@treewalker.org>
Signed-off-by: Mark Brown <broonie@linaro.org>
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As reported by Dave Hansen, sysfs cpu/online shows 1 for
offlined CPUs at boot.
Fix this problem by initializing dev.offline with cpu_online()
when registering a CPU.
References: https://lkml.org/lkml/2013/5/29/403
Reported-and-tested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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We want the changes here.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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regmap-mmio uses a spinlock with spin_lock() and spin_unlock() for locking.
To be able to use the regmap API from different contexts (atomic vs non-atomic),
without the risk of race conditions, we need to use spin_lock_irqsave() and
spin_lock_irqrestore() instead. A new field, the spinlock_flags field, is added
to regmap struct to store the flags between regmap_{,un}lock_spinlock(). The
spinlock_flags field itself is also protected by the spinlock.
Thanks to Stephen Warren for the suggestion of this particular solution.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core fixes from Greg Kroah-Hartman:
"Here are 3 tiny driver core fixes for 3.10-rc2.
A needed symbol export, a change to make it easier to track down
offending sysfs files with incorrect attributes, and a klist bugfix.
All have been in linux-next for a while"
* tag 'driver-core-3.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
klist: del waiter from klist_remove_waiters before wakeup waitting process
driver core: print sysfs attribute name when warning about bogus permissions
driver core: export subsys_virtual_register
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The parameter passed to the regmap lock/unlock callbacks needs to be
map->lock_arg, regcache passes just map. This works fine in the case that no
custom locking callbacks are used since in this case map->lock_arg equals map,
but will break when custom locking callbacks are used. The issue was introduced
in commit 0d4529c5("regmap: make lock/unlock functions customizable") and is
fixed by this patch.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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The parameter passed to the regmap lock/unlock callbacks needs to be
map->lock_arg, regcache passes just map. This works fine in the case that no
custom locking callbacks are used, since in this case map->lock_arg equals map,
but will break when custom locking callbacks are used. The issue was introduced
in commit 0d4529c5 ("regmap: make lock/unlock functions customizable") and is
fixed by this patch.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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It fixes race between udev and hotplugged CPU registration by defining
"online" attribute statically, so that device_add() would create it
before notifying udev about new CPU.
Original issue report is at https://lkml.org/lkml/2012/4/30/198
"
> On Mon, Apr 30, 2012 at 11:36:23AM -0400, Konrad Rzeszutek Wilk wrote:
> > Hey Greg,
> >
> > Hoping you can help with some guidance on how to fix this.
> >
> > The issue is with CPU hotplug is that when a CPU goes up
> > it calls 'arch_register_cpu' which eventually calls
> > register_cpu. That function does these two things:
> >
> > 251 error = device_register(&cpu->dev);
> > 252 if (!error && cpu->hotpluggable)
> > 253 register_cpu_control(cpu);
> >
> > and the device_register creates a nice little SysFS directory:
> >
> > /sys/devices/system/cpu/cpu2/ which at line 251 has the 'add' attribute
> > but no 'online' attribute. udev then tries to echo 1 to the 'online'
> > and it we get:
> > udevd-work[2421]: error opening ATTR{/sys/devices/system/cpu/cpu2/online} for writing: No such file or directory
> >
> > Line 253 creates said 'online' and at that time udev [or the system admin]
> > can write 1 to 'online' and the CPU goes up.
> >
> > So .. any thoughts? Is there some way to inhibit from uevent being sent
> > until line 253 has run?
"
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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"crash_notes" and "crash_notes_size" are dynamically created
with device_create_file() but aren't deleted anywhere.
Define "crash_notes" and "crash_notes_size" statically via
attribute groups so that device_register would create them
automatically and files would be destroyed when CPU is destroyed.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Signed-off-by: Federico Vaga <federico.vaga@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Make it obvious to see what attribute is using bogus permissions.
Signed-off-by: Dave Young <dyoung@redhat.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Modules want to call this function, so it needs to be exported.
Reported-by: Daniel Mack <zonque@gmail.com>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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regmap_debugfs_get_dump_start should return the offset of the register
it should start reading from, However in the current code at one point
the code does not return correct register offset.
With this patch all the returns from this function takes reg_stride in
to consideration to return correct offset.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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A register write to hardware is reasonably unlikely to cause locking
dependency issues, the reason we're tainting is that unexpected changes
in the hardware configuration may confuse drivers.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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If range information has been provided then when we allocate a rbnode
within a range allocate the entire range. The goal is to minimise the
number of reallocations done when combining or extending blocks. At
present only readability and yes_ranges are taken into account, this is
expected to cover most cases efficiently.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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In preparation for being slightly smarter about how we allocate memory
factor out the node allocation.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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Allow drivers to use an access table as part of their implementation.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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Allow drivers to discard parts of the register cache, for example if part
of the hardware has been reset.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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Introduce .offline() and .online() callbacks for memory_subsys
that will allow the generic device_offline() and device_online()
to be used with device objects representing memory blocks. That,
in turn, allows the ACPI subsystem to use device_offline() to put
removable memory blocks offline, if possible, before removing
memory modules holding them.
The 'online' sysfs attribute of memory block devices will attempt to
put them offline if 0 is written to it and will attempt to apply the
previously used online type when onlining them (i.e. when 1 is
written to it).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Vasilis Liaskovitis <vasilis.liaskovitis@profitbricks.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
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Split the ACPI processor driver into two parts, one that is
non-modular, resides in the ACPI core and handles the enumeration
and hotplug of processors and one that implements the rest of the
existing processor driver functionality.
The non-modular part uses an ACPI scan handler object to enumerate
processors on the basis of information provided by the ACPI namespace
and to hook up with the common ACPI hotplug infrastructure. It also
populates the ACPI handle of each processor device having a
corresponding object in the ACPI namespace, which allows the driver
proper to bind to those devices, and makes the driver bind to them
if it is readily available (i.e. loaded) when the scan handler's
.attach() routine is running.
There are a few reasons to make this change.
First, switching the ACPI processor driver to using the common ACPI
hotplug infrastructure reduces code duplication and size considerably,
even though a new file is created along with a header comment etc.
Second, since the common hotplug code attempts to offline devices
before starting the (non-reversible) removal procedure, it will abort
(and possibly roll back) hot-remove operations involving processors
if cpu_down() returns an error code for one of them instead of
continuing them blindly (if /sys/firmware/acpi/hotplug/force_remove
is unset). That is a more desirable behavior than what the current
code does.
Finally, the separation of the scan/hotplug part from the driver
proper makes it possible to simplify the driver's .remove() routine,
because it doesn't need to worry about the possible cleanup related
to processor removal any more (the scan/hotplug part is responsible
for that now) and can handle device removal and driver removal
symmetricaly (i.e. as appropriate).
Some user-visible changes in sysfs are made (for example, the
'sysdev' link from the ACPI device node to the processor device's
directory is gone and a 'physical_node' link is present instead
and a corresponding 'firmware_node' is present in the processor
device's directory, the processor driver is now visible under
/sys/bus/cpu/drivers/ and bound to the processor device), but
that shouldn't affect the functionality that users care about
(frequency scaling, C-states and thermal management).
Tested on my venerable Toshiba Portege R500.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
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Rework the CPU hotplug code in drivers/base/cpu.c to use the
generic offline/online support introduced previously instead of
its own CPU-specific code.
For this purpose, modify cpu_subsys to provide offline and online
callbacks for CONFIG_HOTPLUG_CPU set and remove the code handling
the CPU-specific 'online' sysfs attribute.
This modification is not supposed to change the user-observable
behavior of the kernel (i.e. the 'online' attribute will be present
in exactly the same place in sysfs and should trigger exactly the
same actions as before).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
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In some cases, graceful hot-removal of devices is not possible,
although in principle the devices in question support hotplug.
For example, that may happen for the last CPU in the system or
for memory modules holding kernel memory.
In those cases it is nice to be able to check if the given device
can be gracefully hot-removed before triggering a removal procedure
that cannot be aborted or reversed. Unfortunately, however, the
kernel currently doesn't provide any support for that.
To address that deficiency, introduce support for offline and
online operations that can be performed on devices, respectively,
before a hot-removal and in case when it is necessary (or convenient)
to put a device back online after a successful offline (that has not
been followed by removal). The idea is that the offline will fail
whenever the given device cannot be gracefully removed from the
system and it will not be allowed to use the device after a
successful offline (until a subsequent online) in analogy with the
existing CPU offline/online mechanism.
For now, the offline and online operations are introduced at the
bus type level, as that should be sufficient for the most urgent use
cases (CPUs and memory modules). In the future, however, the
approach may be extended to cover some more complicated device
offline/online scenarios involving device drivers etc.
The lock_device_hotplug() and unlock_device_hotplug() functions are
introduced because subsequent patches need to put larger pieces of
code under device_hotplug_lock to prevent race conditions between
device offline and removal from happening.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
|
