dcscb_allcpus_mask is an array of size 2.

The index variable cluster has to be checked against this limit
before accessing the array.
Signed-off-by: NHeinrich Schuchardt <xypron.glpk@gmx.de>
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NPawel Moll <pawel.moll@arm.com>

Strictly speaking this call is a no-op on the platform where dcscb.c is
used since it only has architected caches.  The call was there as a hint
to people inspired by this code when writing their own backend, but the
hint might not always be correct.

For example, if a PL310 were to be used it wouldn't be safe to call
the regular outer_flush_all() as atomic instructions for locking
are involved in that case and those instructions cannot be assumed to
still be operational after v7_exit_coherency_flush() has returned.
Given no other CPUs (in the cluster) should be running at that point
then standard concurrency concerns wouldn't apply.

So let's simply kill this call for now and enhance the existing comment.
Signed-off-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This code is becoming duplicated in many places.  So let's consolidate
it into a handy macro that is known to be right and available for reuse.
Signed-off-by: NNicolas Pitre <nico@linaro.org>
Acked-by: NDave Martin <Dave.Martin@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

If CONFIG_FRAME_POINTER=y we get the following error:

arch/arm/mach-vexpress/tc2_pm.c: In function 'tc2_pm_down':
arch/arm/mach-vexpress/tc2_pm.c:200:1: error: fp cannot be used in asm here

Let's fix that by explicitly preserving r11 on the stack and removing it
from the clobber list.
Reported-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Reviewed-by: NDave Martin <Dave.Martin@arm.com>
Signed-off-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NOlof Johansson <olof@lixom.net>

Unlike real A15/A7's, the RTSM simulation doesn't appear to hit the
cache when the CTRL.C bit is cleared.  Let's ensure there is no memory
access within the disable and flush cache sequence, including to the
stack.
Signed-off-by: NNicolas Pitre <nico@linaro.org>

Add the required code to properly handle race free platform coherency exit
to the DCSCB power down method.

The power_up_setup callback is used to enable the CCI interface for
the cluster being brought up.  This must be done in assembly before
the kernel environment is entered.

Thanks to Achin Gupta and Nicolas Pitre for their help and
contributions.
Signed-off-by: NDave Martin <dave.martin@linaro.org>
Signed-off-by: NNicolas Pitre <nico@linaro.org>
Reviewed-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: NPawel Moll <pawel.moll@arm.com>

If 4 CPUs are assumed, the A15x1-A7x1 model configuration would never
shut down the initial cluster as the 0xf reset bit mask will never be
observed.  Let's construct this mask based on the provided information
in the DCSCB config register for the number of CPUs per cluster.
Signed-off-by: NNicolas Pitre <nico@linaro.org>
Reviewed-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: NPawel Moll <pawel.moll@arm.com>

It is possible for a CPU to be told to power up before it managed
to power itself down.  Solve this race with a usage count to deal
with this possibility as mandated by the MCPM API definition.
Signed-off-by: Nnicolas Pitre <nico@linaro.org>
Reviewed-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: NPawel Moll <pawel.moll@arm.com>

This adds basic CPU and cluster reset controls on RTSM for the
A15x4-A7x4 model configuration using the Dual Cluster System
Configuration Block (DCSCB).

The cache coherency interconnect (CCI) is not handled yet.
Signed-off-by: NNicolas Pitre <nico@linaro.org>
Reviewed-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: NPawel Moll <pawel.moll@arm.com>