cpufreq: Explicitly include correct DT includes

The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.

Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: armada-37xx: stop using 0 as NULL pointer

Use NULL for NULL pointer to fix the following sparse warning:
drivers/cpufreq/armada-37xx-cpufreq.c:448:32: sparse: warning: Using plain integer as NULL pointer

Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: armada-37xx: forbid cpufreq for 1.2 GHz variant

The 1.2 GHz variant of the Armada 3720 SOC is unstable with DVFS: when
the SOC boots, the WTMI firmware sets clocks and AVS values that work
correctly with 1.2 GHz CPU frequency, but random crashes occur once
cpufreq driver starts scaling.

We do not know currently what is the reason:
- it may be that the voltage value for L0 for 1.2 GHz variant provided
by the vendor in the OTP is simply incorrect when scaling is used,
- it may be that some delay is needed somewhere,
- it may be something else.

The most sane solution now seems to be to simply forbid the cpufreq
driver on 1.2 GHz variant.

Signed-off-by: Marek Behún <kabel@kernel.org>
Fixes: 92ce45fb875d ("cpufreq: Add DVFS support for Armada 37xx")
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: armada-37xx: Fix module unloading

This driver is missing module_exit hook. Add proper driver exit function
which unregisters the platform device and cleans up the data.

Signed-off-by: Pali Rohár <pali@kernel.org>
Tested-by: Tomasz Maciej Nowak <tmn505@gmail.com>
Tested-by: Anders Trier Olesen <anders.trier.olesen@gmail.com>
Tested-by: Philip Soares <philips@netisense.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: armada-37xx: Remove cur_frequency variable

Variable cur_frequency in armada37xx_cpufreq_driver_init() is unused.

Signed-off-by: Pali Rohár <pali@kernel.org>
Acked-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Tested-by: Tomasz Maciej Nowak <tmn505@gmail.com>
Tested-by: Anders Trier Olesen <anders.trier.olesen@gmail.com>
Tested-by: Philip Soares <philips@netisense.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: armada-37xx: Fix determining base CPU frequency

When current CPU load is not L0 then loading armada-37xx-cpufreq.ko driver
fails with following error:

# modprobe armada-37xx-cpufreq
[ 502.702097] Unsupported CPU frequency 250 MHz

This issue was partially fixed by commit 8db82563451f ("cpufreq:
armada-37xx: fix frequency calculation for opp"), but only for calculating
CPU frequency for opp.

Fix this also for determination of base CPU frequency.

Signed-off-by: Pali Rohár <pali@kernel.org>
Acked-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Tested-by: Tomasz Maciej Nowak <tmn505@gmail.com>
Tested-by: Anders Trier Olesen <anders.trier.olesen@gmail.com>
Tested-by: Philip Soares <philips@netisense.com>
Fixes: 92ce45fb875d ("cpufreq: Add DVFS support for Armada 37xx")
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: armada-37xx: Fix driver cleanup when registration failed

Commit 8db82563451f ("cpufreq: armada-37xx: fix frequency calculation for
opp") changed calculation of frequency passed to the dev_pm_opp_add()
function call. But the code for dev_pm_opp_remove() function call was not
updated, so the driver cleanup phase does not work when registration fails.

This fixes the issue by using the same frequency in both calls.

Signed-off-by: Pali Rohár <pali@kernel.org>
Acked-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Tested-by: Tomasz Maciej Nowak <tmn505@gmail.com>
Tested-by: Anders Trier Olesen <anders.trier.olesen@gmail.com>
Tested-by: Philip Soares <philips@netisense.com>
Fixes: 8db82563451f ("cpufreq: armada-37xx: fix frequency calculation for opp")
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: armada-37xx: Fix the AVS value for load L1

The original CPU voltage value for load L1 is too low for Armada 37xx SoC
when base CPU frequency is 1000 or 1200 MHz. It leads to instabilities
where CPU gets stuck soon after dynamic voltage scaling from load L1 to L0.

Update the CPU voltage value for load L1 accordingly when base frequency is
1000 or 1200 MHz. The minimal L1 value for base CPU frequency 1000 MHz is
updated from the original 1.05V to 1.108V and for 1200 MHz is updated to
1.155V. This minimal L1 value is used only in the case when it is lower
than value for L0.

This change fixes CPU instability issues on 1 GHz and 1.2 GHz variants of
Espressobin and 1 GHz Turris Mox.

Marvell previously for 1 GHz variant of Espressobin provided a patch [1]
suitable only for their Marvell Linux kernel 4.4 fork which workarounded
this issue. Patch forced CPU voltage value to 1.108V in all loads. But
such change does not fix CPU instability issues on 1.2 GHz variants of
Armada 3720 SoC.

During testing we come to the conclusion that using 1.108V as minimal
value for L1 load makes 1 GHz variants of Espressobin and Turris Mox boards
stable. And similarly 1.155V for 1.2 GHz variant of Espressobin.

These two values 1.108V and 1.155V are documented in Armada 3700 Hardware
Specifications as typical initial CPU voltage values.

Discussion about this issue is also at the Armbian forum [2].

[1] - https://github.com/MarvellEmbeddedProcessors/linux-marvell/commit/dc33b62c90696afb6adc7dbcc4ebbd48bedec269
[2] - https://forum.armbian.com/topic/10429-how-to-make-espressobin-v7-stable/

Signed-off-by: Pali Rohár <pali@kernel.org>
Acked-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Tested-by: Tomasz Maciej Nowak <tmn505@gmail.com>
Tested-by: Anders Trier Olesen <anders.trier.olesen@gmail.com>
Tested-by: Philip Soares <philips@netisense.com>
Fixes: 1c3528232f4b ("cpufreq: armada-37xx: Add AVS support")
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: armada-37xx: Fix setting TBG parent for load levels

With CPU frequency determining software [1] we have discovered that
after this driver does one CPU frequency change, the base frequency of
the CPU is set to the frequency of TBG-A-P clock, instead of the TBG
that is parent to the CPU.

This can be reproduced on EspressoBIN and Turris MOX:
cd /sys/devices/system/cpu/cpufreq/policy0
echo powersave >scaling_governor
echo performance >scaling_governor

Running the mhz tool before this driver is loaded reports 1000 MHz, and
after loading the driver and executing commands above the tool reports
800 MHz.

The change of TBG clock selector is supposed to happen in function
armada37xx_cpufreq_dvfs_setup. Before the function returns, it does
this:
parent = clk_get_parent(clk);
clk_set_parent(clk, parent);

The armada-37xx-periph clock driver has the .set_parent method
implemented correctly for this, so if the method was actually called,
this would work. But since the introduction of the common clock
framework in commit b2476490ef11 ("clk: introduce the common clock..."),
the clk_set_parent function checks whether the parent is actually
changing, and if the requested new parent is same as the old parent
(which is obviously the case for the code above), the .set_parent method
is not called at all.

This patch fixes this issue by filling the correct TBG clock selector
directly in the armada37xx_cpufreq_dvfs_setup during the filling of
other registers at the same address. But the determination of CPU TBG
index cannot be done via the common clock framework, therefore we need
to access the North Bridge Peripheral Clock registers directly in this
driver.

[1] https://github.com/wtarreau/mhz

Signed-off-by: Marek Behún <kabel@kernel.org>
Acked-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Tested-by: Pali Rohár <pali@kernel.org>
Tested-by: Tomasz Maciej Nowak <tmn505@gmail.com>
Tested-by: Anders Trier Olesen <anders.trier.olesen@gmail.com>
Tested-by: Philip Soares <philips@netisense.com>
Fixes: 92ce45fb875d ("cpufreq: Add DVFS support for Armada 37xx")
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: armada-37xx: Add missing MODULE_DEVICE_TABLE

CONFIG_ARM_ARMADA_37XX_CPUFREQ is tristate option and therefore this
cpufreq driver can be compiled as a module. This patch adds missing
MODULE_DEVICE_TABLE which generates correct modalias for automatic
loading of this cpufreq driver when is compiled as an external module.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Pali Rohár <pali@kernel.org>
Fixes: 92ce45fb875d7 ("cpufreq: Add DVFS support for Armada 37xx")
[ Viresh: Added __maybe_unused ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: dt: fix oops on armada37xx

Commit 0c868627e617e43a295d8 (cpufreq: dt: Allow platform specific
intermediate callbacks) added two function pointers to the
struct cpufreq_dt_platform_data. However, armada37xx_cpufreq_driver_init()
has this struct (pdata) located on the stack and uses only "suspend"
and "resume" fields. So these newly added "get_intermediate" and
"target_intermediate" pointers are uninitialized and contain arbitrary
non-null values, causing all kinds of trouble.

For instance, here is an oops on espressobin after an attempt to change
the cpefreq governor:

[ 29.174554] Unable to handle kernel execute from non-executable memory at virtual address ffff00003f87bdc0
...
[ 29.269373] pc : 0xffff00003f87bdc0
[ 29.272957] lr : __cpufreq_driver_target+0x138/0x580
...

Fixed by zeroing out pdata before use.

Cc: <stable@vger.kernel.org> # v5.7+
Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: armada-37xx: Remove set but not used variable 'freq'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/cpufreq/armada-37xx-cpufreq.c: In function 'armada37xx_cpufreq_avs_setup':
drivers/cpufreq/armada-37xx-cpufreq.c:260:28: warning:
variable 'freq' set but not used [-Wunused-but-set-variable]

It's never used since introduction in commit 1c3528232f4b ("cpufreq:
armada-37xx: Add AVS support")

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: armada-37xx: fix frequency calculation for opp

The frequency calculation was based on the current(max) frequency of the
CPU. However for low frequency, the value used was already the parent
frequency divided by a factor of 2.

Instead of using this frequency, this fix directly get the frequency from
the parent clock.

Fixes: 92ce45fb875d ("cpufreq: Add DVFS support for Armada 37xx")
Cc: <stable@vger.kernel.org>
Reported-by: Christian Neubert <christian.neubert.86@gmail.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: armada-37xx: Add AVS support

Armada 37xx supports Adaptive Voltage Scaling and thanks to this patch a
voltage is associated to each load level.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: add suspend/resume support in Armada 37xx DVFS driver

Add suspend/resume hooks in Armada 37xx DVFS driver to handle S2RAM
operations. As there is currently no 'driver' structure, create one
to store both the regmap and the register values during suspend
operation.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: armada: Free resources on error paths

The resources weren't freed on failures, free them properly.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: armada-37xx: Fix clock leak

There was no clk_put() balancing the clk_get(). This commit fixes it.

Fixes: 92ce45fb875d (cpufreq: Add DVFS support for Armada 37xx)
Cc: 4.16+ <stable@vger.kernel.org> # 4.16+
Reported-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: Add DVFS support for Armada 37xx

This patch adds DVFS support for the Armada 37xx SoCs

There are up to four CPU frequency loads for Armada 37xx controlled by
the hardware.

This driver associates the CPU load level to a frequency, then the
hardware will switch while selecting a load level.

The hardware also can associate a voltage for each level (AVS support)
but it is not yet supported

Tested-by: Andre Heider <a.heider@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>