ARM: mvebu: Hardware coherency support for Armada 375 and 38x

Jason, Gregory, Andrew, Sebastian,

This set of patches add hardware coherency support for the new Armada 375 and Armada 38x SoCs.

Changes since v2:

* Rebased on top of v3.15-rc1. From my side, the patches are ready to apply, so unless comments are made, I will not resend another version.

Changes since v1:

* Rebased on top of current linux-next, and therefore updated to take into account the changes in mach-mvebu, such as Kirkwood/Dove integration. A new version will be sent as soon as 3.15-rc1 is released.

* Removed a debugging message from coherency_type() which was being displayed every time this function was called, to say "Initializing coherency fabric", which was incorrect.

* Delay the initialization of the XOR-based coherency workaround for Armada 375 into the postcore_initcall(), before the bus notifier gets registered. This solves two problems: 1/ the of_update_property() cannot be done as early as it could be done in earlier kernels, and 2/ it avoids having to initialize the MBus driver before the coherency fabric.

* Added a warning message when the XOR-based coherency workaround for Armada 375 is enabled, so that the user at least has a trace in the kernel logs explaining why a XOR engine is not available.

The patches can also be grabbed from:

https://github.com/MISL-EBU-System-SW/mainline-public/tree/3.15-mvebu/coherency

The patch set can be divided in three sections:

* Patches 1, 2, 3 and 4 prepare the introduction of the support for new SoC in the existing coherency code.

The main change is that the mvebu-mbus driver no longer pokes into the Device Tree to find whether hardware I/O coherency is available or not: this information is passed as argument to the mvebu-mbus initialization function. This avoids changing the mvebu-mbus driver to add the compatible strings of all possible coherency fabrics, and also avoids encoding specific conditions in the mvebu-mbus
driver: on Armada 375 and 38x, the hardware I/O coherency can only be enabled in SMP mode.

These preparation patches had already been sent in the past
(http://permalink.gmane.org/gmane.linux.ports.arm.kernel/290780). This round has taken into account the comments I had received on this early version.

* Patches 5, 6, 7 and 8 add the coherency support itself. Patch 4 enables the SCU, patch 5 adds I/O coherency support for 375, patch 6 adds a major workaround to make coherency support actually work on early 375 SOCs and patch 7 adds I/O coherency support for 38x.

* Patches 9 and 10 add the necessary Device Tree informations to enable the coherency.

Best regards,

Thomas

Thomas Petazzoni (10):
ARM: mvebu: prepare coherency code to support more SOCs
ARM: mvebu: add a coherency_available() call
bus: mvebu: pass the coherency availability information at init time
ARM: mvebu: ARM: mvebu: use of_find_matching_node_and_match() in
coherency.c
ARM: mvebu: enable the ARM SCU on Armada 375 and Armada 38x
ARM: mvebu: add Armada 375 support to the coherency code
ARM: mvebu: implement Armada 375 coherency workaround
ARM: mvebu: add Armada 38x support to the coherency code
ARM: mvebu: enable the coherency fabric on Armada 375
ARM: mvebu: enable the coherency fabric on Armada 38x

 .../devicetree/bindings/arm/coherency-fabric.txt   |  32 ++-
 arch/arm/boot/dts/armada-375.dtsi                  |  10 +
 arch/arm/boot/dts/armada-38x.dtsi                  |  10 +
 arch/arm/mach-kirkwood/board-dt.c                  |   2 +-
 arch/arm/mach-mvebu/Kconfig                        |   2 +
 arch/arm/mach-mvebu/board-v7.c                     |  21 +-
 arch/arm/mach-mvebu/coherency.c                    | 262 +++++++++++++++++++--
 arch/arm/mach-mvebu/coherency.h                    |   1 +
 arch/arm/mach-mvebu/dove.c                         |   2 +-
 arch/arm/mach-mvebu/kirkwood.c                     |   2 +-
 drivers/bus/mvebu-mbus.c                           |  11 +-
 include/linux/mbus.h                               |   2 +-
 12 files changed, 315 insertions(+), 42 deletions(-)

1.8.3.2