When we build a kernel with support for both ARMv6 and ARMv7,
gas is trying to be helpful by pointing out that the arm-cci
driver would not work on ARMv6:
/tmp/ccu1LDeU.s: Assembler messages:
/tmp/ccu1LDeU.s:450: Error: selected processor does not support ARM mode `wfi '
/tmp/ccu1LDeU.s:451: Error: selected processor does not support ARM mode `wfe '
make[4]: *** [drivers/bus/arm-cci.o] Error 1
We know that the driver will only be used on ARMv7, hence we
can annotate the inline assembly listing to allow those instructions.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Nicolas Pitre <nico@linaro.org>
Cc: Dave Martin <dave.martin@linaro.org>
This provides cci_enable_port_for_self(). This is the counterpart to
cci_disable_port_by_cpu(self).
This is meant to be called from the MCPM machine specific power_up_setup
callback code when the appropriate affinity level needs to be initialized.
The code therefore has to be position independent as the MMU is still off
and it cannot rely on any stack space.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Dave Martin <dave.martin@linaro.org>
On ARM multi-cluster systems coherency between cores running on
different clusters is managed by the cache-coherent interconnect (CCI).
It allows broadcasting of TLB invalidates and memory barriers and it
guarantees cache coherency at system level through snooping of slave
interfaces connected to it.
This patch enables the basic infrastructure required in Linux to handle and
programme the CCI component.
Non-local variables used by the CCI management functions called by power
down function calls after disabling the cache must be flushed out to main
memory in advance, otherwise incoherency of those values may occur if they
are sitting in the cache of some other CPU when power down functions
execute. Driver code ensures that relevant data structures are flushed
from inner and outer caches after the driver probe is completed.
CCI slave port resources are linked to set of CPUs through bus masters
phandle properties that link the interface resources to masters node in
the device tree.
Documentation describing the CCI DT bindings is provided with the patch.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
