In every other instance where mrc is used the coprocessor operand
is prefix with p (e.g. p15). Use the p prefix in this case too.
This fixes a build issue when using LLVM's integrated assembler:
  arch/arm/mach-mvebu/coherency_ll.S:69:6: error: invalid operand for instruction
   mrc 15, 0, r3, cr0, cr0, 5
       ^
  arch/arm/mach-mvebu/pmsu_ll.S:19:6: error: invalid operand for instruction
   mrc 15, 0, r0, cr0, cr0, 5 @ get the CPU ID
       ^
Signed-off-by: NStefan Agner <stefan@agner.ch>
Acked-by: NNicolas Pitre <nico@fluxnic.net>
Signed-off-by: NGregory CLEMENT <gregory.clement@bootlin.com>

The ll_add_cpu_to_smp_group(), ll_enable_coherency() and
ll_disable_coherency() are used on Armada XP to control the coherency
fabric. However, they make the assumption that the coherency fabric is
always available, which is currently a correct assumption but will no
longer be true with a followup commit that disables the usage of the
coherency fabric when the conditions are not met to use it.

Therefore, this commit modifies those functions so that they check the
return value of ll_get_coherency_base(), and if the return value is 0,
they simply return without configuring anything in the coherency
fabric.

The ll_get_coherency_base() function is also modified to properly
return 0 when the function is called with the MMU disabled. In this
case, it normally returns the physical address of the coherency
fabric, but we now check if the virtual address is 0, and if that's
case, return a physical address of 0 to indicate that the coherency
fabric is not enabled.
Signed-off-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: <stable@vger.kernel.org> # v3.8+
Acked-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Link: https://lkml.kernel.org/r/1415871540-20302-2-git-send-email-thomas.petazzoni@free-electrons.comSigned-off-by: NJason Cooper <jason@lakedaemon.net>

ARMv6 and greater introduced a new instruction ("bx") which can be used
to return from function calls.  Recent CPUs perform better when the
"bx lr" instruction is used rather than the "mov pc, lr" instruction,
and this sequence is strongly recommended to be used by the ARM
architecture manual (section A.4.1.1).

We provide a new macro "ret" with all its variants for the condition
code which will resolve to the appropriate instruction.

Rather than doing this piecemeal, and miss some instances, change all
the "mov pc" instances to use the new macro, with the exception of
the "movs" instruction and the kprobes code.  This allows us to detect
the "mov pc, lr" case and fix it up - and also gives us the possibility
of deploying this for other registers depending on the CPU selection.
Reported-by: NWill Deacon <will.deacon@arm.com>
Tested-by: Stephen Warren <swarren@nvidia.com> # Tegra Jetson TK1
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr> # mioa701_bootresume.S
Tested-by: Andrew Lunn <andrew@lunn.ch> # Kirkwood
Tested-by: NShawn Guo <shawn.guo@freescale.com>
Tested-by: Tony Lindgren <tony@atomide.com> # OMAPs
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com> # Armada XP, 375, 385
Acked-by: Sekhar Nori <nsekhar@ti.com> # DaVinci
Acked-by: Christoffer Dall <christoffer.dall@linaro.org> # kvm/hyp
Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com> # PXA3xx
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> # Xen
Tested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> # ARMv7M
Tested-by: Simon Horman <horms+renesas@verge.net.au> # Shmobile
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

In the refactoring of the coherency fabric assembly code, a function
called ll_get_cpuid() was created to factorize common logic between
functions adding CPU to the SMP coherency group, enabling and
disabling the coherency.

However, the name of the function is highly misleading: ll_get_cpuid()
makes one think tat it returns the ID of the CPU, i.e 0 for CPU0, 1
for CPU1, etc. In fact, this is not at all what this function returns:
it returns a CPU mask for the current CPU, usable for the coherency
fabric configuration and control registers.

Therefore this commit renames this function to
ll_get_coherency_cpumask(), and adds additional comments on top of the
function to explain in more details what it does, and also how the
endianess issue is handled.
Signed-off-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Link: https://lkml.kernel.org/r/1400762882-10116-5-git-send-email-thomas.petazzoni@free-electrons.comAcked-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NJason Cooper <jason@lakedaemon.net>

This commit makes no functional change, it only improves a bit the
various code comments in mach-mvebu/coherency_ll.S, by fixing a few
typos and adding a few more details.
Signed-off-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Link: https://lkml.kernel.org/r/1400762882-10116-4-git-send-email-thomas.petazzoni@free-electrons.comAcked-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NJason Cooper <jason@lakedaemon.net>

This commit does not make any functional change, it only fixes the
indentation of a few assembly instructions in
arch/arm/mach-mvebu/coherency_ll.S.
Signed-off-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Link: https://lkml.kernel.org/r/1400762882-10116-3-git-send-email-thomas.petazzoni@free-electrons.comAcked-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NJason Cooper <jason@lakedaemon.net>

As part of the introduction of the cpuidle support for Armada XP, the
coherency code was significantly reworked, especially in the
coherency_ll.S file. However, when the ll_get_cpuid function was
created, the big-endian specific code that switches the endianess of
the register was not updated properly.

This patch fixes this code, and therefore makes big endian systems
bootable again.
Signed-off-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Link: https://lkml.kernel.org/r/1400762882-10116-2-git-send-email-thomas.petazzoni@free-electrons.com
Fixes: 2e8a5942 ("ARM: mvebu: Split low level functions to manipulate HW coherency")
Reported-by: NKevin Hilman <khilman@linaro.org>
Cc: Kevin Hilman <khilman@linaro.org>
Acked-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NJason Cooper <jason@lakedaemon.net>

When going to deep idle we need to disable the SoC snooping (aka
hardware coherency support). Playing with the coherency fabric
requires to use assembly code to be sure that the compiler doesn't
reorder the instructions nor do wrong optimization.
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Link: https://lkml.kernel.org/r/1397488214-20685-7-git-send-email-gregory.clement@free-electrons.comSigned-off-by: NJason Cooper <jason@lakedaemon.net>

Actually enabling coherency and adding a CPU on a SMP group are two
different operations which can be done separately. This patch splits
this in two functions.

Moreover as they use common pattern, this patch also creates local low
level functions (ll_get_coherency_base and ll_get_cpuid) to be used by
the exposed functions (ll_add_cpu_to_smp_group and
ll_enable_coherency)
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Link: https://lkml.kernel.org/r/1397488214-20685-6-git-send-email-gregory.clement@free-electrons.comSigned-off-by: NJason Cooper <jason@lakedaemon.net>

ll_set_cpu_coherent is always used on the current CPU, so instead of
passing the CPU id as argument, ll_set_cpu_coherent() can find it by
itself.
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Link: https://lkml.kernel.org/r/1397488214-20685-4-git-send-email-gregory.clement@free-electrons.comAcked-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: NJason Cooper <jason@lakedaemon.net>

In order to be able to deal with the MMU enabled and the MMU disabled
cases, the base address of the coherency registers was passed to the
function. The address by itself was not interesting as it can't change
for a given SoC, the only thing we need is to have a distinction
between the physical or the virtual address.

This patch add a check of the MMU bit to choose the accurate address,
then the calling function doesn't have to pass this information.
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Link: https://lkml.kernel.org/r/1397488214-20685-3-git-send-email-gregory.clement@free-electrons.comSigned-off-by: NJason Cooper <jason@lakedaemon.net>

Add indication we can run these cores in BE mode, and ensure that the
secondary CPU is set to big-endian mode in the initialisation code as
the initial code runs little-endian.
Signed-off-by: NBen Dooks <ben.dooks@codethink.co.uk>
Tested-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: NJason Cooper <jason@lakedaemon.net>

When adding CPU to the SMP group and enabling the coherency on this
CPU we must protect the register access.
The previous implementation claims to be atomic but doesn't provide
any protection against parallel access to the coherency fabric control
and configuration registers.

This patch fixes this by using the ldrex and strex mechanism.
This method should be used in all accesses to those registers.

[gregory.clement@free-electrons.com: fixed the commit's topic]
Signed-off-by: NNadav Haklai <nadavh@marvell.com>
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NJason Cooper <jason@lakedaemon.net>

The Armada 370 and Armada XP SOCs have a coherency fabric unit which
is responsible for ensuring hardware coherency between all CPUs and
between CPUs and I/O masters. This patch provides the basic support
needed for SMP.
Signed-off-by: NYehuda Yitschak <yehuday@marvell.com>
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Reviewed-by: NWill Deacon <will.deacon@arm.com>