[PATCH v6] Add MediaTek MT6779 devapc driver

[Neal Liu <neal.liu@mediatek.com>]

These patch series introduce a MediaTek MT6779 devapc driver.

MediaTek bus fabric provides TrustZone security support and data protection to prevent slaves from being accessed by unexpected masters.
The security violation is logged and sent to the processor for further analysis or countermeasures.

Any occurrence of security violation would raise an interrupt, and it will be handled by mtk-devapc driver.
The violation information is printed in order to find the murderer.

changes since v5:
- remove redundant write reg operation.
- use static variable of vio_dbgs instead.
- add stop_devapc() if driver is removed.

changes since v4:
- refactor data structure.
- merge two simple functions into one.
- refactor register setting to prevent too many function call overhead.

changes since v3:
- revise violation handling flow to make it more easily to understand
  hardware behavior.
- add more comments to understand how hardware works.

changes since v2:
- pass platform info through DT data.
- remove unnecessary function.
- remove slave_type because it always equals to 1 in current support SoC.
- use vio_idx_num instread of list all devices' index.
- add more comments to describe hardware behavior.

changes since v1:
- move SoC specific part to DT data.
- remove unnecessary boundary check.
- remove unnecessary data type declaration.
- use read_poll_timeout() instread of for loop polling.
- revise coding style elegantly.


*** BLURB HERE ***

Neal Liu (2):
  dt-bindings: devapc: add bindings for mtk-devapc
  soc: mediatek: add mt6779 devapc driver

 .../bindings/soc/mediatek/devapc.yaml         |  58 ++++
 drivers/soc/mediatek/Kconfig                  |   9 +
 drivers/soc/mediatek/Makefile                 |   1 +
 drivers/soc/mediatek/mtk-devapc.c             | 320 ++++++++++++++++++
 4 files changed, 388 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/soc/mediatek/devapc.yaml
 create mode 100644 drivers/soc/mediatek/mtk-devapc.c

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2.18.0