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>
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>
With SCU standby enabled, SCU CLK will be turned off when all processors
are in WFI mode. And the clock will be turned on when any processor
leaves WFI mode.
This behavior should be preferable in terms of power efficiency of
system idle. So let's set the SCU standby bit to enable the support in
function scu_enable().
Cortex-A9 earlier than r2p0 has no standby bit in SCU, so we need to
skip setting the bit for those.
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
Acked-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Use macro instead of magic number for SCU enable bit.
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
Acked-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The smp_scu driver needs to use the relaxed readl/write accessors
to avoid any issues with the endian mode the processor core is in.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Both calls are identical currently. This patch prepares to deprecate
read_cpuid on machines without cp15.
Also move an unconditional usage of read_cpuid_cachetype to a more local
scope as read_cpuid_cachetype uses read_cpuid, too.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Message-Id: 1359646587-1788-1-git-send-email-u.kleine-koenig@pengutronix.de
With commit a0ae0240 (ARM: kernel: add device tree init map function),
the cpu id value may include the cluster id and is no longer 0-3, so we
need to mask it in scu_power_mode to get the local cpu number. Since we
are only dealing with the cpu we are running on, the cluster id should
not ever be needed.
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
scu_power_mode changes the power mode for the current CPU, which it
determines from smp_processor_id(). However, this assumes that the
physical CPU number is equal to Linux's logical CPU number and if this
is not true, we will power off the wrong CPU.
This patch uses cpu_logical_map to translate the logical CPU number
into a physical one in scu_power_mode.
Reported-by: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
When Cortex-A9 MPCore resumes from Dormant or Shutdown modes,
SCU needs to be re-enabled. This patch removes __init annotation
from function scu_enable(), so that platform resume procedure can
call it to re-enable SCU.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch implements a workaround for erratum 764369 affecting
Cortex-A9 MPCore with two or more processors (all current revisions).
Under certain timing circumstances, a data cache line maintenance
operation by MVA targeting an Inner Shareable memory region may fail to
proceed up to either the Point of Coherency or to the Point of
Unification of the system. This workaround adds a DSB instruction before
the relevant cache maintenance functions and sets a specific bit in the
diagnostic control register of the SCU.
Cc: <stable@kernel.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The scu_power_mode function can be used on UP builds as it drives signals
to an SOC power controller. So make it selectable for !SMP.
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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>
If Linux is running in non-secure mode, this register may have been
already initialised and writing to the control register not allowed.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
On MP systems, the data loaded by CPU0 before the SCU was initialised
may not be visible to the other CPUs.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This also includes the following compile fix:
This patch includes 'asm/cacheflush.h' which is needed to use
'flush_cache_all()' function.
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
