arm64: cpuidle: remove generic cpuidle support

The arm64 support of the generic ARM cpuidle driver was removed. This
let us remove all support code for it.

Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20220529181329.2345722-3-michael@walle.cc
Signed-off-by: Will Deacon <will@kernel.org>

arm64: Add cpuidle context save/restore helpers

As we need to start doing some additional work on all idle
paths, let's introduce a set of macros that will perform
the work related to the GICv3 pseudo-NMI idle entry exit.

Stubs are introduced to 32bit ARM for compatibility.
As these helpers are currently unused, there is no functional
change.

Tested-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210615111227.2454465-2-maz@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arm64: kernel: rename __cpu_suspend to keep it aligned with arm

This patch renames __cpu_suspend to cpu_suspend so that it's aligned
with ARM32. It also removes the redundant wrapper created.

This is in preparation to implement generic PSCI system suspend using
the cpu_{suspend,resume} which now has the same interface on both ARM
and ARM64.

Cc: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

ARM64: cpuidle: Rename cpu_init_idle to a common function name

With this change the cpuidle-arm64.c file calls the same function name
for both ARM and ARM64.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Kevin Hilman <khilman@linaro.org>
Acked-by: Rob Herring <robherring2@gmail.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

ARM: cpuidle: Add a cpuidle ops structure to be used for DT

The current state of the different cpuidle drivers is the different PM
operations are passed via the platform_data using the platform driver
paradigm.

This approach allowed to split the low level PM code from the arch specific
and the generic cpuidle code.

Unfortunately there are complaints about this approach as, in the context of the
single kernel image, we have multiple drivers loaded in memory for nothing and
the platform driver is not adequate for cpuidle.

This patch provides a common interface via cpuidle ops for all new cpuidle
driver and a definition for the device tree.

It will allow with the next patches to a have a common definition with ARM64
and share the same cpuidle driver.

The code is optimized to use the __init section intensively in order to reduce
the memory footprint after the driver is initialized and unify the function
names with ARM64.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Kevin Hilman <khilman@linaro.org>
Acked-by: Rob Herring <robherring2@gmail.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

arm64: cpuidle: add asm/proc-fns.h inclusion

ARM64 CPUidle driver requires the cpu_do_idle function so that it can
be used to enter the shallowest idle state, and it is declared in
asm/proc-fns.h.

The current ARM64 CPUidle driver does not include asm/proc-fns.h
explicitly and it has so far relied on implicit inclusion from other
header files.

Owing to some header dependencies reshuffling this currently triggers
build failures when CONFIG_ARM64_64K_PAGES=y:

drivers/cpuidle/cpuidle-arm64.c: In function "arm64_enter_idle_state"
drivers/cpuidle/cpuidle-arm64.c:42:3: error: implicit declaration of
function "cpu_do_idle" [-Werror=implicit-function-declaration]
cpu_do_idle();
^

This patch adds the explicit inclusion of the asm/proc-fns.h header file
in the arm64 asm/cpuidle.h header file, so that the build breakage is fixed
and the required header inclusion is added to the appropriate arch back-end
CPUidle header, already included by the CPUidle arm64 driver, where
CPUidle arch related function declarations belong.

Reported-by: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: kernel: remove ARM64_CPU_SUSPEND config option

ARM64_CPU_SUSPEND config option was introduced to make code providing
context save/restore selectable only on platforms requiring power
management capabilities.

Currently ARM64_CPU_SUSPEND depends on the PM_SLEEP config option which
in turn is set by the SUSPEND config option.

The introduction of CPU_IDLE for arm64 requires that code configured
by ARM64_CPU_SUSPEND (context save/restore) should be compiled in
in order to enable the CPU idle driver to rely on CPU operations
carrying out context save/restore.

The ARM64_CPUIDLE config option (ARM64 generic idle driver) is therefore
forced to select ARM64_CPU_SUSPEND, even if there may be (ie PM_SLEEP)
failed dependencies, which is not a clean way of handling the kernel
configuration option.

For these reasons, this patch removes the ARM64_CPU_SUSPEND config option
and makes the context save/restore dependent on CPU_PM, which is selected
whenever either SUSPEND or CPU_IDLE are configured, cleaning up dependencies
in the process.

This way, code previously configured through ARM64_CPU_SUSPEND is
compiled in whenever a power management subsystem requires it to be
present in the kernel (SUSPEND || CPU_IDLE), which is the behaviour
expected on ARM64 kernels.

The cpu_suspend and cpu_init_idle CPU operations are added only if
CPU_IDLE is selected, since they are CPU_IDLE specific methods and
should be grouped and defined accordingly.

PSCI CPU operations are updated to reflect the introduced changes.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: kernel: introduce cpu_init_idle CPU operation

The CPUidle subsystem on ARM64 machines requires the idle states
implementation back-end to initialize idle states parameter upon
boot. This patch adds a hook in the CPU operations structure that
should be initialized by the CPU operations back-end in order to
provide a function that initializes cpu idle states.

This patch also adds the infrastructure to arm64 kernel required
to export the CPU operations based initialization interface, so
that drivers (ie CPUidle) can use it when they are initialized
at probe time.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>