ACPI: Separate adding ACPI device objects from probing ACPI drivers

Split the ACPI namespace scanning for devices into two passes, such
that struct acpi_device objects are registerd in the first pass
without probing ACPI drivers and the drivers are probed against them
directly in the second pass.

There are two main reasons for doing that.

First, the ACPI PCI root bridge driver's .add() routine,
acpi_pci_root_add(), causes struct pci_dev objects to be created for
all PCI devices under the given root bridge.  Usually, there are
corresponding ACPI device nodes in the ACPI namespace for some of
those devices and therefore there should be "companion" struct
acpi_device objects to attach those struct pci_dev objects to.  These
struct acpi_device objects should exist when the corresponding
struct pci_dev objects are created, but that is only guaranteed
during boot and not during hotplug.  This leads to a number of
functional differences between the boot and the hotplug cases which
are not strictly necessary and make the code more complicated.

For example, this forces the ACPI PCI root bridge driver to defer the
registration of the just created struct pci_dev objects and to use a
special .start() callback routine, acpi_pci_root_start(), to make
sure that all of the "companion" struct acpi_device objects will be
present at PCI devices registration time during hotplug.

If those differences can be eliminated, we will be able to
consolidate the boot and hotplug code paths for the enumeration and
registration of PCI devices and to reduce the complexity of that
code quite a bit.

The second reason is that, in general, it should be possible to
resolve conflicts of resources assigned by the BIOS to different
devices represented by ACPI namespace nodes before any drivers bind
to them and before they are attached to "companion" objects
representing physical devices (such as struct pci_dev).  However, for
this purpose we first need to enumerate all ACPI device nodes in the
given namespace scope.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
ACPI: Change the ordering of PCI root bridge driver registrarion

Instead of running acpi_pci_root_init() from a separate subsys
initcall, call it directly from acpi_scan_init() before scanning the
ACPI namespace for the first time, so that the PCI root bridge
driver's .add() routine, acpi_pci_root_start(), is always run
before binding ACPI drivers or attaching "companion" device objects
to struct acpi_device objects below the root bridge's device node in
the ACPI namespace.

The first, simpler reason for doing this is that it makes the
situation during boot more similar to the situation during hotplug,
in which the ACPI PCI root bridge driver is always present.

The second reason is that acpi_pci_root_init() causes struct pci_dev
objects to be created for all PCI devices below the bridge and
these objects may be necessary for whatever is done with the other
ACPI device nodes in that namespace scope.  For example, devices
created by acpi_create_platform_device() sometimes may need to be
added to the device hierarchy as children of PCI bridges.  For this
purpose, however, the struct pci_dev objects representing those
bridges need to exist before the platform devices in question are
registered.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
ACPI: Make acpi_bus_add() and acpi_bus_start() visibly different

The current ACPI namespace scanning code suggests that acpi_bus_add()
and acpi_bus_start() share some code.  In fact, however, they are
completely different code paths (except for the initial checks), so
refactor the code to make that distinction visibly clear.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
ACPI: Reduce the usage of struct acpi_bus_ops

Objects of type struct acpi_bus_ops are currently used to pass
information between different parts of the ACPI namespace scanning
code, sometimes in quite convoluted ways.  It turns out that that
is not necessary in some cases, so simplify the code by reducing
the utilization of struct acpi_bus_ops objects where clearly
possible.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
ACPI: Replace struct acpi_bus_ops with enum type

Notice that one member of struct acpi_bus_ops, acpi_op_add, is not
used anywhere any more and the relationship between its remaining
members, acpi_op_match and acpi_op_start, is such that it doesn't
make sense to set the latter without setting the former at the same
time.  Therefore, replace struct acpi_bus_ops with new a enum type,
enum acpi_bus_add_type, with three values, ACPI_BUS_ADD_BASIC,
ACPI_BUS_ADD_MATCH, ACPI_BUS_ADD_START, corresponding to
both acpi_op_match and acpi_op_start unset, acpi_op_match set and
acpi_op_start unset, and both acpi_op_match and acpi_op_start set,
respectively.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
ACPI: Change the ordering of acpi_bus_check_add()

If acpi_bus_check_add() is called for a handle already having an
existing struct acpi_device object attached, it is not necessary to
check the type and status of the device correspondig to it, so
change the ordering of acpi_bus_check_add() to avoid that.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
ACPI / PCI: Fold acpi_pci_root_start() into acpi_pci_root_add()

Move the code from the ACPI PCI root bridge's .start() callback
routine, acpi_pci_root_start(), directly into acpi_pci_root_add()
and drop acpi_pci_root_start().

It is safe to do that, because it is now always guaranteed that
when struct pci_dev objects are created, their companion struct
acpi_device objects are already present, so it is not necessary to
wait for them to be created before calling pci_bus_add_devices().

This change was previously proposed in a different form by
Yinghai Lu.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
ACPI: Remove acpi_start_single_object() and acpi_bus_start()

The ACPI PCI root bridge driver was the only ACPI driver implementing
the .start() callback, which isn't used by any ACPI drivers any more
now.

For this reason, acpi_start_single_object() has no purpose any more,
so remove it and all references to it.  Also remove
acpi_bus_start_device(), whose only purpose was to call
acpi_start_single_object().

Moreover, since after the removal of acpi_bus_start_device() the
only purpose of acpi_bus_start() remains to call
acpi_update_all_gpes(), move that into acpi_bus_add() and drop
acpi_bus_start() too, remove its header from acpi_bus.h and
update all of its former users accordingly.

This change was previously proposed in a different from by
Yinghai Lu.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
ACPI: Remove the arguments of acpi_bus_add() that are not used

Notice that acpi_bus_add() uses only 2 of its 4 arguments and
redefine its header to match the body.  Update all of its callers as
necessary and observe that this leads to quite a number of removed
lines of code (Linus will like that).

Add a kerneldoc comment documenting acpi_bus_add() and wonder how
its callers make wrong assumptions about the second argument (make
note to self to take care of that later).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
ACPI: Drop the second argument of acpi_bus_scan()

After the removal of acpi_start_single_object() and acpi_bus_start()
the second argument of acpi_bus_scan() is not necessary any more,
so drop it and update acpi_bus_check_add() accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
ACPI: Replace ACPI device add_type field with a match_driver flag

After the removal of the second argument of acpi_bus_scan() there is
no difference between the ACPI_BUS_ADD_MATCH and ACPI_BUS_ADD_START
add types, so the add_type field in struct acpi_device may be
replaced with a single flag.  Do that calling the flag match_driver.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
ACPI: Make acpi_bus_scan() and acpi_bus_add() take only one argument

The callers of acpi_bus_add() usually assume that if it has
succeeded, then a struct acpi_device object has been attached to
the handle passed as the first argument.  Unfortunately, however,
this assumption is wrong, because acpi_bus_scan(), and acpi_bus_add()
too as a result, may return a pointer to a different struct
acpi_device object on success (it may be an object corresponding to
one of the descendant ACPI nodes in the namespace scope below that
handle).

For this reason, the callers of acpi_bus_add() who care about
whether or not a struct acpi_device object has been created for
its first argument need to check that using acpi_bus_get_device()
anyway, so the second argument of acpi_bus_add() is not really
useful for them.  The same observation applies to acpi_bus_scan()
executed directly from acpi_scan_init().

Therefore modify the relevant callers of acpi_bus_add() to check the
existence of the struct acpi_device in question with the help of
acpi_bus_get_device() and drop the no longer necessary second
argument of acpi_bus_add().  Accordingly, modify acpi_scan_init() to
use acpi_bus_get_device() to get acpi_root and drop the no longer
needed second argument of acpi_bus_scan().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
ACPI: Add .setup() and .cleanup() callbacks to struct acpi_bus_type

Add two new callbacks,.setup() and .cleanup(), struct acpi_bus_type
and modify acpi_platform_notify() to call .setup() after executing
acpi_bind_one() successfully and acpi_platform_notify_remove() to
call .cleanup() before running acpi_unbind_one().  This will allow
the users of struct acpi_bus_type, PCI in particular, to specify
operations to be executed right after the given device has been
associated with a companion struct acpi_device and right before
it's going to be detached from that companion, respectively.

The main motivation is to be able to get rid of acpi_pci_bind()
and acpi_pci_unbind(), which are horrible horrible stuff.  [In short,
there are three problems with them: The way they populate the .bind()
and .unbind() callbacks of ACPI devices is rather less than
straightforward, they require special hotplug-specific paths to be
present in the ACPI namespace scanning code and by the time
acpi_pci_unbind() is called the PCI device object in question may
not exist any more.]

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
ACPI / PCI: Rework the setup and cleanup of device wakeup

Currently, the ACPI wakeup capability of PCI devices is set up
in two different places, partially in acpi_pci_bind() where
runtime wakeup is initialized and partially in
platform_pci_wakeup_init(), where system wakeup is initialized.
The cleanup is only done in acpi_pci_unbind() and it only covers
runtime wakeup.

Use the new .setup() and .cleanup() callbacks in struct acpi_bus_type
to consolidate that code and do the setup and the cleanup each in one
place.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
ACPI / PCI: Move the _PRT setup and cleanup code to pci-acpi.c

Move the code related to _PRT setup and removal and to power
resources from acpi_pci_bind() and acpi_pci_unbind() to the .setup()
and .cleanup() callbacks in acpi_pci_bus and remove acpi_pci_bind()
and acpi_pci_unbind() that have no purpose any more.  Accordingly,
remove the code related to device .bind() and .unbind() operations
from the ACPI PCI root bridge driver.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
ACPI: Drop ACPI device .bind() and .unbind() callbacks

Drop the .bind() and .unbind() that have no more users from
struct acpi_device_ops and remove all of the code referring to
them from drivers/acpi/scan.c.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
cpuidle: fix lock contention in the idle path

Commit bf4d1b5 (cpuidle: support multiple drivers) introduced
locking in cpuidle_get_cpu_driver(), which is used in the
idle_call() function.

This leads to a contention problem with a large number of CPUs,
because they all try to run the idle routine at the same time.

The lock can be safely removed because of how is used the cpuidle
API.  Namely, cpuidle_register_driver() is called first, but the
cpuidle idle function is not entered before cpuidle_register_device()
is called, because the cpuidle device is not enabled then. Moreover,
cpuidle_unregister_driver(), which would reset the driver value to
NULL, is not called before cpuidle_unregister_device().

All of the cpuidle drivers use the API in the same way.

In general, a cleanup around the lock is necessary and a proper
refcounting mechanism should be used to ensure the consistency in the
API (for example, cpuidle_unregister_driver() should fail if the
driver's refcount is not 0). However, these modifications will require
some code reorganization and rewrite which will be too intrusive for
a fix.

For this reason, fix the contention problem introduced by commit
bf4d1b5 by simply removing the locking from cpuidle_get_cpu_driver(),
which restores the original behavior of that routine.

[rjw: Changelog.]
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / power: Remove useless message from device registering routine

After commit 71fbad6 (PCI/ACPI: Notify PCI devices when their power
resource is turned on) made acpi_pci_bind() call
acpi_power_resource_register_device(), the debug message at the end
of the latter appears in the kernel log for every PCI device that
doesn't happen to have power resources assigned (which is the vast
majority of them).  However, this message is totally useless, because
it doesn't even say which device it is about.  Moreover, it is
misleading, because it only means that the given device has no power
resources, which isn't exceptional at all.

Remove that useless message altogether and simplify
acpi_power_resource_register_device() slightly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI: Remove unused struct acpi_pci_root.id member

This member is never initialized and never referenced, so remove it.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branch 'acpi-assorted-next' into linux-next

* acpi-assorted-next:
  ACPI / power: Remove useless message from device registering routine