If big.LITTLE driver is initialized even when MCPM is unavailable,
we get the below warning the first time cpu tries to enter deeper
C-states.
------------[ cut here ]------------
WARNING: CPU: 4 PID: 0 at kernel/arch/arm/common/mcpm_entry.c:130 mcpm_cpu_suspend+0x6d/0x74()
Modules linked in:
CPU: 4 PID: 0 Comm: swapper/4 Not tainted 3.19.0-rc3-00007-gaf5a2cb1ad5c-dirty #11
Hardware name: ARM-Versatile Express
[<c0013fa5>] (unwind_backtrace) from [<c001084d>] (show_stack+0x11/0x14)
[<c001084d>] (show_stack) from [<c04fe7f1>] (dump_stack+0x6d/0x78)
[<c04fe7f1>] (dump_stack) from [<c0020645>] (warn_slowpath_common+0x69/0x90)
[<c0020645>] (warn_slowpath_common) from [<c00206db>] (warn_slowpath_null+0x17/0x1c)
[<c00206db>] (warn_slowpath_null) from [<c001cbdd>] (mcpm_cpu_suspend+0x6d/0x74)
[<c001cbdd>] (mcpm_cpu_suspend) from [<c03c6919>] (bl_powerdown_finisher+0x21/0x24)
[<c03c6919>] (bl_powerdown_finisher) from [<c001218d>] (cpu_suspend_abort+0x1/0x14)
[<c001218d>] (cpu_suspend_abort) from [<00000000>] ( (null))
---[ end trace d098e3fd00000008 ]---
This patch fixes the issue by checking for the availability of MCPM
before initializing the big.LITTLE cpuidle driver
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
The only place where the time is invalid is when the ACPI_CSTATE_FFH entry
method is not set. Otherwise for all the drivers, the time can be correctly
measured.
Instead of duplicating the CPUIDLE_FLAG_TIME_VALID flag in all the drivers
for all the states, just invert the logic by replacing it by the flag
CPUIDLE_FLAG_TIME_INVALID, hence we can set this flag only for the acpi idle
driver, remove the former flag from all the drivers and invert the logic with
this flag in the different governor.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
With the introduction of DT based idle states, CPUidle drivers for ARM
can now initialize idle states data through properties in the device tree.
This patch adds code to the big.LITTLE CPUidle driver to dynamically
initialize idle states data through the updated device tree source file.
Cc: Chander Kashyap <k.chander@samsung.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Exynos 5800 is big.LITTLE SoC compatible with the 5420. Add the
compatible string so this driver works on the 5800.
Tested on exynos5800-peach-pi (aka Samsung Chromebook2)
Signed-off-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Commit af040ffc9b ("ARM: make it easier to check the CPU part number
correctly") changed ARM_CPU_PART_X masks, and the way they are returned and
checked against. Usage of read_cpuid_part_number() is now deprecated, and
calling places updated accordingly. This actually broke cpuidle-big_little
initialization, as bl_idle_driver_init() performs a check using an hardcoded
mask on cpu_id.
Create an interface to perform the check (that is now even easier to read).
Define also a proper mask (ARM_CPU_PART_MASK) that makes this kind of checks
cleaner and helps preventing bugs in the future. Update usage accordingly.
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This driver will be used by many big.Little Soc's. As of now it does
string matching of hardcoded compatible string to init the driver. This
comparison list will keep on growing with addition of new SoC's.
Hence add of_device_id structure to collect the compatible strings of
SoC's using this driver.
Signed-off-by: Chander Kashyap <chander.kashyap@linaro.org>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
The big.LITTLE architecture is composed of two clusters of cpus. One cluster
contains less powerful but more energy efficient processors and the other
cluster groups the powerful but energy-intensive cpus.
The TC2 testchip implements two clusters of CPUs (A7 and A15 clusters in
a big.LITTLE configuration) connected through a CCI interconnect that manages
coherency of their respective L2 caches and intercluster distributed
virtual memory messages (DVM).
TC2 testchip integrates a power controller that manages cores resets, wake-up
IRQs and cluster low-power states. Power states are managed at cluster
level, which means that voltage is removed from a cluster iff all cores
in a cluster are in a wfi state. Single cores can enter a reset state
which is identical to wfi in terms of power consumption but simplifies the
way cluster states are entered.
This patch provides a multiple driver CPU idle implementation for TC2
which paves the way for a generic big.LITTLE idle driver for all
upcoming big.LITTLE based systems on chip.
The driver relies on the MCPM infrastructure to coordinate and manage
core power states; in particular MCPM allows to suspend specific cores
and hides the CPUs coordination required to shut-down clusters of CPUs.
Power down sequences for the respective clusters are implemented in the
MCPM TC2 backend, with all code needed to clean caches and exit coherency.
The multiple driver CPU idle infrastructure allows to define different
C-states for big and little cores, determined at boot by checking the
part id of the possible CPUs and initializing the respective logical
masks in the big and little drivers.
Current big.little systems are composed of A7 and A15 clusters, as
implemented in TC2, but in the future that may change and the driver
will have evolve to retrieve what is a 'big' cpu and what is a 'little'
cpu in order to build the correct topology.
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Amit Kucheria <amit.kucheria@linaro.org>
Cc: Olof Johansson <olof@lixom.net>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
