By using device and further data node references, allow direct references
to endpoints. These are of form

	Package() { \DEV, "portX", "endpointY" }

where X is the number of the port and Y is the number of the endpoint.
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The fwnode graph API is preferred over the ACPI graph API. Therefore
make the ACPI graph API private, and use it as a back-end for the
fwnode graph API only.

Unused functionality is removed while the functionality actually used
remains the same.
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Implement references to non-device nodes using the first package
entry in the hierarchical data extension reference, the second one
being the name of the referred object.

The data node references are parsed just after the device arguments
before the integer arguments. If there are no strings after the
device arguments, the parsing works exactly as it used to be.

Referring to a data node called "node" under device DEV, with
integer arguments 0, 2 would thus look like:

	Package() { DEV, "node", 0, 2 }
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Convert all users of struct acpi_reference_args to more generic
fwnode_reference_args. This will

 1) avoid an ACPI specific references to device nodes with integer
    arguments as well as

 2) allow making references to nodes other than device nodes in ACPI.

As a by-product, convert the fwnode interger arguments to u64. The
arguments were 64-bit integers on ACPI but the fwnode arguments were
just 32-bit.
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Constify device_get_match_data() as OF and ACPI variants return
constant value.
Acked-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Do the renaming to be consistent with its sibling, i.e.
of_device_get_match_data().

No functional change.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Now that we have a get_match_data() callback as part of the firmware node,
implement the ACPI specific piece for it.
Signed-off-by: NSinan Kaya <okaya@codeaurora.org>
Acked-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NVinod Koul <vinod.koul@intel.com>

Fix more return codes for device property: Align return codes of
__acpi_node_get_property_reference().

In particular, what was missed previously:

 -EPROTO could be returned in certain cases, now -EINVAL;
 -EINVAL was returned if the property was not found, now -ENOENT;
 -EINVAL was returned also if the index was higher than the number of
         entries in a package, now -ENOENT.
Reported-by: NHyungwoo Yang <hyungwoo.yang@intel.com>
Fixes: 3e3119d3 (device property: Introduce fwnode_property_get_reference_args)
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Tested-by: NHyungwoo Yang <hyungwoo.yang@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

acpi_fwnode_get_reference_args(), the function implementing ACPI
support for fwnode_property_get_reference_args(), returns directly
error codes from __acpi_node_get_property_reference(). The latter
uses different error codes than the OF implementation. In particular,
the OF implementation uses -ENOENT to indicate that the property is
not found, a reference entry is empty and there are no more
references.

Document and align the error codes for property for
fwnode_property_get_reference_args() so that they match with
of_parse_phandle_with_args().

Fixes: 3e3119d3 (device property: Introduce fwnode_property_get_reference_args)
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The recently merged patch "ACPI: Prepare for constifying
acpi_get_next_subnode() fwnode argument" was part of a patchset
constifying the fwnode arguments across the fwnode property API. The
purpose of the patch was to allow returning non-const fwnodes from a data
structure the root of which is const.

Unfortunately the patch introduced the functionality, in particular when
starting parsed from an ACPI device node, the hierarchical data extension
nodes would not be enumerated.

Restore the old behaviour while still retaining constness properties of
the patch.

Fixes: 01c1da28 "ACPI: Prepare for constifying acpi_get_next_subnode() fwnode argument"
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Due to commit db3e50f3 (device property: Get rid of struct
fwnode_handle type field), ACPI_HANDLE() inadvertently became
a GPL-only call. The call path that led to that was:

ACPI_HANDLE()
    ACPI_COMPANION()
        to_acpi_device_node()
            is_acpi_device_node()
                acpi_device_fwnode_ops
                    DECLARE_ACPI_FWNODE_OPS(acpi_device_fwnode_ops);

...and the new DECLARE_ACPI_FWNODE_OPS() includes
EXPORT_SYMBOL_GPL, whereas previously it was a static struct.

In order to avoid changing any of that, let's instead provide ever
so slightly better encapsulation of those struct fwnode_operations
instances. Those do not really need to be directly used in
inline function calls in header files. Simply moving two small
functions (is_acpi_device_node and is_acpi_data_node) out of
acpi_bus.h, and into a .c file, does that.

That leaves the internals of struct fwnode_operations as GPL-only
(which I think was the intent all along), but un-breaks any driver
code out there that relies on the ACPI subsystem's being (historically)
an EXPORT_SYMBOL-usable system. By that, I mean, ACPI_HANDLE() and
other basic ACPI calls were non-GPL-protected.

Also, while I'm there, remove a tiny bit of redundancy that was missed
in the earlier commit, by having is_acpi_node() use the other two
routines, instead of checking fwnode directly.

Fixes: db3e50f3 (device property: Get rid of struct fwnode_handle type field)
Signed-off-by: NJohn Hubbard <jhubbard@nvidia.com>
Acked-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

acpi_graph_get_child_prop_value() is intended to find a child node with a
certain property value pair. The check

	if (!fwnode_property_read_u32(fwnode, prop_name, &nr))
		continue;

is faulty: fwnode_property_read_u32() returns zero on success, not on
failure, leading to comparing values only if the searched property was not
found.

Moreover, the check is made against the parent device node instead of
the child one as it should be.

Fixes: 79389a83 (ACPI / property: Add support for remote endpoints)
Reported-by: NHyungwoo Yang <hyungwoo.yang@intel.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Cc: 4.12+ <stable@vger.kernel.org> # 4.12+
[ rjw: Changelog ]
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

While the rest of the world has standardized on _DSD as the way to store
device properties in AML (introduced with ACPI 5.1 in 2014), Apple has
been using a custom _DSM to achieve the same for much longer (ever since
they switched from DeviceTree-based PowerPC to Intel in 2005, verified
with MacOS X 10.4.11).

The theory of operation on macOS is as follows:  AppleACPIPlatform.kext
invokes mergeEFIproperties() and mergeDSMproperties() for each device to
merge properties conveyed by EFI drivers as well as properties stored in
AML into the I/O Kit registry from which they can be retrieved by
drivers.  We've been supporting EFI properties since commit 58c5475a
("x86/efi: Retrieve and assign Apple device properties").  The present
commit adds support for _DSM properties, thereby completing our support
for Apple device properties.  The _DSM properties are made available
under the primary fwnode, the EFI properties under the secondary fwnode.
So for devices which possess both property types, they can all be
elegantly accessed with the uniform API in <linux/property.h>.

Until recently we had no need to support _DSM properties, they contained
only uninteresting garbage.  The situation has changed with MacBooks and
MacBook Pros introduced since 2015:  Their keyboard is attached with SPI
instead of USB and the _CRS data which is necessary to initialize the
spi driver only contains valid information if OSPM responds "false" to
_OSI("Darwin").  If OSPM responds "true", _CRS is empty and the spi
driver fails to initialize.  The rationale is very simple, Apple only
cares about macOS and Windows:  On Windows, _CRS contains valid data,
whereas on macOS it is empty.  Instead, macOS gleans the necessary data
from the _DSM properties.

Since Linux deliberately defaults to responding "true" to _OSI("Darwin"),
we need to emulate macOS' behaviour by initializing the spi driver with
data returned by the _DSM.

An out-of-tree driver for the SPI keyboard exists which currently binds
to the ACPI device, invokes the _DSM, parses the returned package and
instantiates an SPI device with the data gleaned from the _DSM:
https://github.com/cb22/macbook12-spi-driver/commit/9a416d699ef4
https://github.com/cb22/macbook12-spi-driver/commit/0c34936ed9a1

By adding support for Apple's _DSM properties in generic ACPI code, the
out-of-tree driver will be able to register as a regular SPI driver,
significantly reducing its amount of code and improving its chances to
be mainlined.

The SPI keyboard will not be the only user of this commit:  E.g. on the
MacBook8,1, the UART-attached Bluetooth device likewise returns empty
_CRS data if OSPM returns "true" to _OSI("Darwin").

The _DSM returns a Package whose format unfortunately deviates slightly
from the _DSD spec:  The properties are marshalled up in a single Package
as alternating key/value elements, unlike _DSD which stores them as a
Package of 2-element Packages.  The present commit therefore converts
the Package to _DSD format and the ACPI core can then treat the data as
if Apple would follow the standard.

Well, except for one small annoyance:  The properties returned by the
_DSM only ever have one of two types, Integer or Buffer.  The former is
retrievable as usual with device_property_read_u64(), but the latter is
not part of the _DSD spec and it is not possible to retrieve Buffer
properties with the device_property_read_*() functions due to the type
checking performed in drivers/acpi/property.c.  It is however possible
to retrieve them with acpi_dev_get_property().  Apple is using the
Buffer type somewhat sloppily to store null-terminated strings but also
integers.  The real data type is not distinguishable by the ACPI core
and the onus is on the caller to use the contents of the Buffer in an
appropriate way.

In case Apple moves to _DSD in the future, this commit first checks for
_DSD and falls back to _DSM only if _DSD is not found.
Tested-by: NRonald Tschalär <ronald@innovation.ch>
Acked-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Fabricated devices such as LNXPWRBN lack a handle, causing evaluation
of _CCA and _DSD to always fail with AE_BAD_PARAMETER.  While that is
merely a (negligible) waste of processing power, evaluating a _DSM for
them (such as Apple's device properties _DSM which we're about to add)
results in an ugly error:

    ACPI: \: failed to evaluate _DSM (0x1001)

Avoid by not evaluating _DSD and the upcoming _DSM for devices without
handle.
Acked-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

There are new types and helpers that are supposed to be used in new code.

As a preparation to get rid of legacy types and API functions do
the conversion here.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The new fwnode_property_get_reference_args() interface amends the fwnode
property API with the functionality of both of_parse_phandle_with_args()
and __acpi_node_get_property_reference().

The semantics is slightly different: the cells property is ignored on ACPI
as the number of arguments can be explicitly obtained from the firmware
interface.
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Make fwnode arguments to the fwnode property API const.
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Constify internal ACPI fwnode arguments in preparation for the same in
fwnode API.
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Make local variables const (head) or add new variables; adev was used for
two purposes: to refer the root device node and its children. The two
purposes are separated by this patch.

This is preparation for making fwnode arguments const for fwnode ops.
Don't constify the argument itself quite yet as this is used as a callback
function.
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Instead of relying on the struct fwnode_handle type field, define
fwnode_operations structs for all separate types of fwnodes. To find out
the type, compare to the ops field to relevant ops structs.

This change has two benefits:

1. it avoids adding the type field to each and every instance of struct
fwnode_handle, thus saving memory and

2. makes the ops field the single factor that defines both the types of
the fwnode as well as defines the implementation of its operations,
decreasing the possibility of bugs when developing code dealing with
fwnode internals.
Suggested-by: NRob Herring <robh@kernel.org>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Add fwnode_device_is_available() to tell whether the device corresponding
to a certain fwnode_handle is available for use.
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Move firmware specific implementations of the fwnode graph operations to
firmware specific locations.
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The device and fwnode property API supports Devicetree, ACPI and pset
properties. The implementation of this functionality for each firmware
type was embedded in the fwnode property core. Move it out to firmware
type specific locations, making it easier to maintain.

Depends-on: ("of: Move OF property and graph API from base.c to property.c")
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Functionally fwnode_property_read_string_array() should match
of_property_read_string_array() and work as a drop-in substitute for the
latter. of_property_read_string_array() returns the number of strings read
if the target string pointer array is non-NULL. Make
fwnode_property_read_string_array() do the same.
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

DT has had concept of remote endpoints for some time already. It makes
possible to reference another firmware node through a property called
remote-endpoint. This is already used by some subsystems like v4l2 for
parsing hardware properties related to camera.

This patch adds ACPI support for remote endpoints utilizing _DSD
hierarchical data extensions.
Signed-off-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The ACPI _DSD hierarchical data extension makes it possible to have
hierarchies deeper than one level in similar way than DT allows. These
"subsubnodes" have not been accessible because device property
implementation only provides device_get_next_child_node() that is limited
to direct descendants of a device.

We need this ability in order support things like remote endpoints
currently supported in DT with of_graph_* APIs.

Modify acpi_get_next_subnode() to accept fwnode handle instead and update
callers accordingly. Also add a new function fwnode_get_next_child_node()
that works directly with fwnodes and modify device_get_next_child_node() to
call it directly. While there add a macro fwnode_for_each_child_node()
analogous to the current device_for_each_child_node() but it works with
fwnodes instead of devices.

Link: http://www.uefi.org/sites/default/files/resources/_DSD-hierarchical-data-extension-UUID-v1.pdfSigned-off-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Sometimes it is useful to be able to navigate firmware node hierarchy
upwards toward parent nodes. ACPI device nodes are pretty much already
supported because ACPICA provides acpi_get_parent(). ACPI data nodes,
however, are all below the same parent ACPI device. Their hierarchy is
created by "linking" each other using references in the value field.

Add parent pointer to the parent data node while we create them so it is
easy to navigate the hierarchy backwards. We use this parent pointer in a
new function acpi_node_get_parent() that is able to extract parent of both
ACPI firmware node types.
Signed-off-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The definition document of the Hierarchical Properties Extension UUID
for _DSD has been changed recently to allow local references to be
used as sub-node link targets (previously, it only allowed strings to
be used for that purpose).

Update the code in drivers/acpi/property.c to reflect that change.

Link: http://www.uefi.org/sites/default/files/resources/_DSD-hierarchical-data-extension-UUID-v1.1.pdfTested-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

DT allows holes or empty phandles for references. This is used for example
in SPI subsystem where some chip selects are native and others are regular
GPIOs. In ACPI _DSD we currently do not support this but instead the
preceding reference consumes all following integer arguments.

For example we would like to support something like the below ASL fragment
for SPI:

  Package () {
      "cs-gpios",
      Package () {
          ^GPIO, 19, 0, 0, // GPIO CS0
          0,               // Native CS
          ^GPIO, 20, 0, 0, // GPIO CS1
      }
  }

The zero in the middle means "no entry" or NULL reference. To support this
we change acpi_data_get_property_reference() to take firmware node and
num_args as argument and rename it to __acpi_node_get_property_reference().
The function returns -ENOENT if the given index resolves to "no entry"
reference and -ENODATA when there are no more entries in the property.

We then add static inline wrapper acpi_node_get_property_reference() that
passes MAX_ACPI_REFERENCE_ARGS as num_args to support the existing
behaviour which some drivers have been relying on.
Signed-off-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

When an ACPI node has both ACPI device nodes and ACPI data nodes,
acpi_get_next_subnode() will return the ACPI data nodes of its last
parsed child.

To avoid that, make acpi_get_next_subnode() go back to the original
ACPI device object when all of the device node children of it have
been found already.
Signed-off-by: NIrina Tirdea <irina.tirdea@intel.com>
[ rjw: Changelog ]
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Change return code to be in align with OF and built-in device properties error
codes. In particular -EINVAL means property is not found.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The correct scope for looking up the objects to generate data packages for
data-only subnodes pointed to by another data-only subnode is the scope
of the parent of that subnode and not the scope containing the _DSD object
at the top of the hierarchy (the latter works only if all of the objects
returning data-only subnode packages in a given hierarchy are in the same
scope).

Fix the code to work as expected.

Fixes: 445b0eb0 (ACPI / property: Add support for data-only subnodes)
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: NMika Westerberg <mika.westerberg@linux.intel.com>

Make device_get_next_child_node() work with ACPI data-only subnodes
introduced previously.

Namely, replace acpi_get_next_child() with acpi_get_next_subnode()
that can handle (and return) child device objects as well as child
data-only subnodes of the given device and modify the ACPI part
of the GPIO subsystem to handle data-only subnodes returned by it.

To that end, introduce acpi_node_get_gpiod() taking a struct
fwnode_handle pointer as the first argument.  That argument may
point to an ACPI device object as well as to a data-only subnode
and the function should do the right thing (ie. look for the matching
GPIO descriptor correctly) in either case.

Next, modify fwnode_get_named_gpiod() to use acpi_node_get_gpiod()
instead of acpi_get_gpiod_by_index() which automatically causes
devm_get_gpiod_from_child() to work with ACPI data-only subnodes
that may be returned by device_get_next_child_node() which in turn
is required by the users of that function (the gpio_keys_polled
and gpio-leds drivers).
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>

Modify is_acpi_node() to return "true" for ACPI data-only subnodes as
well as for ACPI device objects and change the name of to_acpi_node()
to to_acpi_device_node() so it is clear that it covers ACPI device
objects only.  Accordingly, introduce to_acpi_data_node() to cover
data-only subnodes in an analogous way.

With that, make the fwnode_property_* family of functions work with
ACPI data-only subnodes introduced previously.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: NMika Westerberg <mika.westerberg@linux.intel.com>

Add infrastructure needed to expose data-only subnodes of ACPI
device objects introduced previously via sysfs.

Each data-only subnode is represented as a sysfs directory under
the directory corresponding to its parent object (a device or a
data-only subnode).  Each of them has a "path" attribute (containing
the full ACPI namespace path to the object the subnode data come from)
at this time.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: NMika Westerberg <mika.westerberg@linux.intel.com>

In some cases, the information expressed via device properties is
hierarchical by nature.  For example, the properties of a composite
device consisting of multiple semi-dependent components may need
to be represented in the form of a tree of property data sets
corresponding to specific components of the device.

Unfortunately, using ACPI device objects for this purpose turns out
to be problematic, mostly due to the assumption made by some operating
systems (that platform firmware generally needs to work with) that
each device object in the ACPI namespace represents a device requiring
a separate driver.  That assumption leads to complications which
reportedly are impractically difficult to overcome and a different
approach is needed for the sake of interoperability.

The approach implemented here is based on extending _DSD via pointers
(links) to additional ACPI objects returning data packages formatted
in accordance with the _DSD formatting rules defined by Section 6.2.5
of ACPI 6.  Those additional objects are referred to as data-only
subnodes of the device object containing the _DSD pointing to them.

The links to them need to be located in a separate section of the
_DSD data package following UUID dbb8e3e6-5886-4ba6-8795-1319f52a966b
referred to as the Hierarchical Data Extension UUID as defined in [1].
Each of them is represented by a package of two strings.  The first
string in that package (the key) is regarded as the name of the
data-only subnode pointed to by the link.  The second string in it
(the target) is expected to hold the ACPI namespace path (possibly
utilizing the usual ACPI namespace search rules) of an ACPI object
evaluating to a data package extending the _DSD.

The device properties initialization code follows those links,
creates a struct acpi_data_node object for each of them to store
the data returned by the ACPI object pointed to by it and processes
those data recursively (which may lead to the creation of more
struct acpi_data_node objects if the returned data package contains
the Hierarchical Data Extension UUID section with more links in it).

All of the struct acpi_data_node objects are present until the the
ACPI device object containing the _DSD with links to them is deleted
and they are deleted along with that object.

[1]: http://www.uefi.org/sites/default/files/resources/_DSD-hierarchical-data-extension-UUID-v1.pdfSigned-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: NMika Westerberg <mika.westerberg@linux.intel.com>

Move the extraction of _DSD properties from acpi_init_properties()
to a separate routine called acpi_extract_properties() to make the
subsequent changes more straightforward.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: NMika Westerberg <mika.westerberg@linux.intel.com>

Obviously in the current place the 'else' keyword is redundant, though it seems
quite correct when we check if nval is in allowed range.

Reattach the condition branch there.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Use a #defined symbol ACPI_DT_NAMESPACE_HID instead of the PRP0001
string.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: NHanjun Guo <hanjun.guo@linaro.org>

Refine the check for the presence of the "compatible" property
if the PRP0001 device ID is present in the device's list of
ACPI/PNP IDs to also print the message if _DSD is missing
entirely or the format of it is incorrect.

One special case to take into accout is that the "compatible"
property need not be provided for devices having the PRP0001
device ID in their lists of ACPI/PNP IDs if they are ancestors
of PRP0001 devices with the "compatible" property present.
This is to cover heriarchies of device objects where the kernel
is only supposed to use a struct device representation for the
topmost one and the others represent, for example, functional
blocks of a composite device.

While at it, reduce the log level of the message to "info"
and reduce the log level of the "broken _DSD" message to
"debug" (noise reduction).
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>