History log of /linux-master/arch/arm/include/asm/smp_scu.h
Revision Date Author Comments
# b2441318 01-Nov-2017 Greg Kroah-Hartman <gregkh@linuxfoundation.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>


# 936a4174 17-Sep-2017 Martin Blumenstingl <martin.blumenstingl@googlemail.com>

ARM: smp_scu: allow the platform code to read the SCU CPU status

On Amlogic Meson8 / Meson8m2 (both Cortex-A9) and Meson8b (Cortex-A5)
the CPU hotplug code needs to wait until the SCU status of the CPU that
is being taken offline is SCU_PM_POWEROFF.
Provide a utility function (which can be invoked for example from
.cpu_kill()) which allows reading the SCU status of a CPU.

While here, replace the magic number 0x3 with a preprocessor macro
(SCU_CPU_STATUS_MASK) so we don't have to duplicate this magic number in
the new function.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>


# 0606326e 17-Sep-2017 Martin Blumenstingl <martin.blumenstingl@googlemail.com>

ARM: smp_scu: add a helper for powering on a specific CPU

To boot the secondary CPUs on the Amlogic Meson8/Meson8m2 (Cortex-A9)
and Meson8b (Cortex-A5) SoCs we have to enable SCU mode SCU_PM_NORMAL,
otherwise the secondary cores will not start.
This patch adds a scu_cpu_power_enable() function which can be used to
enable SCU_PM_NORMAL for a specific (logical) CPU. An internal helper
function is also created, to avoid code duplication with
scu_power_mode().

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>


# fed3c155 17-Jul-2017 Johan Hovold <johan@kernel.org>

ARM: 8689/1: scu: add missing errno include

Add missing errno include to make the header self-contained and avoid
compilation breakage when compiling shared code without
CONFIG_HAVE_ARM_SCU.

Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>


# af040ffc 24-Jun-2014 Russell King <rmk+kernel@arm.linux.org.uk>

ARM: make it easier to check the CPU part number correctly

Ensure that platform maintainers check the CPU part number in the right
manner: the CPU part number is meaningless without also checking the
CPU implement(e|o)r (choose your preferred spelling!) Provide an
interface which returns both the implementer and part number together,
and update the definitions to include the implementer.

Mark the old function as being deprecated... indeed, using the old
function with the definitions will now always evaluate as false, so
people must update their un-merged code to the new function. While
this could be avoided by adding new definitions, we'd also have to
create new names for them which would be awkward.

Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>


# 2abc75a8 26-Jun-2013 Nishanth Menon <nm@ti.com>

ARM: scu: provide inline dummy functions when SCU is not present

On platforms such as Cortex-A15 based OMAP5, SCU is not used, however
since much code is shared between Cortex-A9 based OMAP4 (which uses
SCU) and OMAP5, It does help to have inline functions returning error
values when SCU is not present on the platform.

arch/arm/mach-omap2/omap-smp.c which is common between OMAP4 and 5
handles the SCU usage only for OMAP4.

This fixes the following build failure with OMAP5 only build:
arch/arm/mach-omap2/built-in.o: In function `omap4_smp_init_cpus':
arch/arm/mach-omap2/omap-smp.c:185: undefined reference to `scu_get_core_count'
arch/arm/mach-omap2/built-in.o: In function `omap4_smp_prepare_cpus':
arch/arm/mach-omap2/omap-smp.c:211: undefined reference to `scu_enable'

Reported-by: Pekon Gupta <pekon@ti.com>
Reported-by: Vincent Stehlé <v-stehle@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>


# eed88123 31-Jan-2013 Rob Herring <rob.herring@calxeda.com>

ARM: scu: add empty scu_enable for !CONFIG_SMP

Add an empty version of scu_enable for !SMP builds. This fixes
compile error for highbank suspend code on !SMP builds.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>


# e9d6b335 21-Jan-2013 Hiroshi Doyu <hdoyu@nvidia.com>

ARM: Add API to detect SCU base address from CP15

Add API to detect SCU base address from CP15.

Signed-off-by: Hiroshi Doyu <hdoyu@nvidia.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Stephen Warren <swarren@nvidia.com>


# 292ec42a 04-Feb-2011 Russell King <rmk+kernel@arm.linux.org.uk>

ARM: pm: add function to set WFI low-power mode for SMP CPUs

Add a function to set the SCU low-power mode for SMP CPUs. This
centralizes this functionality rather than having to expose the
SCU register definitions to each platform.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>


# a8cbcd92 16-May-2009 Russell King <rmk@dyn-67.arm.linux.org.uk>

[ARM] smp: separate SCU support code from realview

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>


# 49613d4d 16-May-2009 Russell King <rmk@dyn-67.arm.linux.org.uk>

[ARM] smp: SCU is used on non-realview platforms

The SCU can be used by non-realview platforms, so make it visible
for other people to use rather than having them copy the header file.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>