ARM: cacheflush: avoid clobbering the frame pointer

Thumb2 uses R7 rather than R11 as the frame pointer, and even if we
rarely use a frame pointer to begin with when building in Thumb2 mode,
there are cases where it is required by the compiler (Clang when
inserting profiling hooks via -pg)

However, preserving and restoring the frame pointer is risky, as any
unhandled exceptions raised in the mean time will produce a bogus
backtrace, and it would be better not to touch the frame pointer at all.
This is the case even when CONFIG_FRAME_POINTER is not set, as the
unwind directive used by the unwinder may also use R7 or R11 as the
unwind anchor, even if the frame pointer is not managed strictly
according to the frame pointer ABI.

So let's tweak the cacheflush asm code not to clobber R7 or R11 at all,
so that we can drop R7 from the clobber lists of the inline asm blocks
that call these routines, and remove the code that preserves/restores
R11.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

ARM: exynos: MCPM: Restore big.LITTLE cpuidle support

Call exynos_cpu_power_up(cpunr) unconditionally. This is needed by the
big.LITTLE cpuidle driver and has no side-effects on other code paths.

The additional soft-reset call during little core power up has been added
to properly boot all cores on the Exynos5422-based boards with secure
firmware (like Odroid XU3/XU4 family). This however broke big.LITTLE
CPUidle driver, which worked only on boards without secure firmware (like
Peach-Pit/Pi Chromebooks). Apply the workaround only when board is
running under secure firmware.

Fixes: 833b5794e330 ("ARM: EXYNOS: reset Little cores when cpu is up")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

ARM: exynos: Fix infinite loops on CPU powerup failure

Add timeout to infinite loops during the CPU powerup procedures. It
is better to report an error instead of busylooping for infinite time
in case of failure.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

ARM: EXYNOS: Add SPDX license identifiers

Replace GPL license statements with SPDX license identifiers (GPL-2.0
and GPL-2.0+).

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

ARM: 8641/1: treewide: Replace uses of virt_to_phys with __pa_symbol

All low-level PM/SMP code using virt_to_phys() should actually use
__pa_symbol() against kernel symbols. Update code where relevant to move
away from virt_to_phys().

Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

ARM: EXYNOS: Annotate iomem and pm_data pointers __ro_after_init

The pointers to __iomem sysram and exynos_pm_data are set only during
initcalls. Later the pointers itself are used only in read-only way so
we can mark them __ro_after_init to increase code safeness.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

ARM: EXYNOS: Move pmu specific headers under "linux/soc/samsung"

Moving Exynos PMU specific header file into "include/linux/soc/samsung"
thus updated affected files under "mach-exynos" to use new location of
these header files.

Signed-off-by: Amit Daniel Kachhap <amitdanielk@gmail.com>
[tested on Peach-Pi (Exynos5880)]
Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
[for testing on Trats2 (Exynos4412) and Odroid XU3 (Exynos5422)]
Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>

ARM: EXYNOS: reset Little cores when cpu is up

The cpu booting of exynos5422 has been still broken since we discussed
it in last year[1]. This patch is inspired from Odroid XU3
code (Actually, it was from samsung exynos vendor kernel)[2]. This weird
reset code was founded exynos5420 octa cores series SoCs and only
required for the first boot core is the Little core (Cortex A7).
Some of the exynos5420 boards and all of the exynos5422 boards will require
this code.

There is two ways to check the little core is the first cpu. One is
checking GPG2CON[1] GPIO value and the other is checking the cluster
number of the first cpu. I selected the latter because it's more easier
than the former.

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-June/350632.html
[2] https://patchwork.kernel.org/patch/6782891/

Cc: Kevin Hilman <khilman@kernel.org>
Cc: Javier Martinez Canillas <javier@osg.samsung.com>
Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Tested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Chanho Park <parkch98@gmail.com>
Cc: <stable@vger.kernel.org> # 4.1+
[k.kozlowski: Adding stable for v4.1+, reformat comment]
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>

ARM: Exynos: migrate DCSCB to the new MCPM backend abstraction

The custom suspend callback is removed for this change. The extra call
to exynos_cpu_power_up(() that was present at the end of exynos_suspend()
is now relocated to the cpu_is_up callback.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>

ARM: EXYNOS: Use MCPM call-backs to support S2R on exynos5420

Use the MCPM layer to handle core suspend/resume on Exynos5420.
Also, restore the entry address setup code post-resume.

Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

ARM: 8129/1: errata: work around Cortex-A15 erratum 830321 using dummy strex

On revisions of Cortex-A15 prior to r3p3, a CLREX instruction at PL1 may
falsely trigger a watchpoint exception, leading to potential data aborts
during exception return and/or livelock.

This patch resolves the issue in the following ways:

- Replacing our uses of CLREX with a dummy STREX sequence instead (as
we did for v6 CPUs).

- Removing the clrex code from v7_exit_coherency_flush and derivatives,
since this only exists as a minor performance improvement when
non-cached exclusives are in use (Linux doesn't use these).

Benchmarking on a variety of ARM cores revealed no measurable
performance difference with this change applied, so the change is
performed unconditionally and no new Kconfig entry is added.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

ARM: EXYNOS: Refactored code for using PMU address via DT

Under "arm/mach-exynos" many files are using PMU register offsets.
Since we have added support for accessing PMU base address via DT,
now we can remove PMU mapping from exynosX_iodesc. Let's convert
all these access using iomapped address.
This will help us in removing static mapping of PMU base address
as well as help in reducing dependency over machine header files.
Thus helping for migration of PMU implementation from machine to
driver folder which can be reused for ARM64 based SoC.

Also as we have removed static mappings from "regs-pmu.h" it does
not need map.h anymore. But "platsmp.c" needed this and till now it
got included indirectly. So lets move header inclusion of
"mach/map.h" from "regs-pmu.h" to "platsmp.c".

Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

ARM: EXYNOS: Support cluster power off on exynos5420/5800

Turning off a cluster when all 4 cores of the cluster are powered off
saves power significantly. Powering off the A15 L2 alone gives around
100mW in savings. Add support for powering off the A15/A7 clusters on
exynos5420/5800.

The patch enables specific register bits which ensure that:
- cluster L2 will be turned on before the first man is powered up.
- last man will be turned off before the cluster L2 is turned off.
- core is powered down before powering it up.

Remove the exynos_cluster_power_control function completely as we can
rely on the above mentioned bits rather than polling the cluster power
status register.

Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

ARM: EXYNOS: populate suspend and powered_up callbacks for mcpm

In order to support cpuidle through mcpm, suspend and powered-up
callbacks are required in mcpm platform code.
Hence populate the same callbacks.

Signed-off-by: Chander Kashyap <chander.kashyap@linaro.org>
Signed-off-by: Chander Kashyap <k.chander@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

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>

ARM: 8083/1: exynos: activate the CCI on boot CPU/cluster using the MCPM loopback

The Chromebook firmware doesn't enable the CCI for the boot cpu, and
arguably it shouldn't have to either. Let's have the kernel handle the

CCI on its own for the boot CPU the same way it does it for secondary CPUs
by using the MCPM loopback.

This allows to boot all 8 cores on exynos5420-peach-pit,
exynos5800-peach-pi and ARM Chromebook 2.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Tushar Behera <tushar.b@samsung.com>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Tested-by: Kevin Hilman <khilman@linaro.org>
Tested-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

ARM: EXYNOS: Don't rely on firmware's secondary_cpu_start for mcpm

On exynos mcpm systems the firmware is hardcoded to jump to an address
in SRAM (0x02073000) when secondary CPUs come up. By default the
firmware puts a bunch of code at that location. That code expects the
kernel to fill in a few slots with addresses that it uses to jump back
to the kernel's entry point for secondary CPUs.

Originally (on prerelease hardware) this firmware code contained a
bunch of workarounds to deal with boot ROM bugs. However on all
shipped hardware we simply use this code to redirect to a kernel
function for bringing up the CPUs.

Let's stop relying on the code provided by the bootloader and just
plumb in our own (simple) code jump to the kernel. This has the nice
benefit of fixing problems due to the fact that older bootloaders
(like the one shipped on the Samsung Chromebook 2) might have put
slightly different code into this location.

Once suspend/resume is implemented for systems using exynos-mcpm we'll
need to make sure we reinstall our fixed up code after resume. ...but
that's not anything new since IRAM (and thus the address of the
mcpm_entry_point) is lost across suspend/resume anyway.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Acked-by: Kevin Hilman <khilman@linaro.org>
Tested-by: Kevin Hilman <khilman@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

ARM: EXYNOS: mcpm rename the power_down_finish

Since commit 166aaf39 ("ARM: 8029/1: mcpm: Rename the power_down_finish()
functions to be less confusing") changed the name of power_down_finish to
wait_for_cpu_powerdown, so use new member name wait_for_cpu_powerdown.

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

ARM: EXYNOS: Enable mcpm for dual-cluster exynos5800 SoC

The exynos5800 is very similar to exynos5420. We can re-use
the existing MCPM support for exynos5800 for secondary boot
-up and switching.

Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

ARM: EXYNOS: Add MCPM call-back functions

Add machine-dependent MCPM call-backs for Exynos5420. These are used
to power up/down the secondary CPUs during boot, shutdown, s2r and
switching.

Signed-off-by: Thomas Abraham <thomas.ab@samsung.com>
Signed-off-by: Inderpal Singh <inderpal.s@samsung.com>
Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Reviewed-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>