[RFC PATCH v2 0/6] add support for CDX bus controller

[Nipun Gupta]

Devices in FPGA can be added/modified dynamically on run-time.
These devices are exposed on system bus to embedded CPUs.

Xilinx CDX bus, caters to the requirement for dynamically
discovered FPGA devices. These devices are added as platform
devices where fwnode is created using 'software nodes' in
Linux framework.

This RFC:
- Intrduces the CDX bus controller and platform device
  creation for the devices on the CDX bus.
- Add rescan and reset support for the CDX buses as well
  as reset of the devices on the CDX bus.
- VFIO platform reset support for CDX bus.
- creates a sysfs entry to expose the compatible string
  for platform devices.

Please NOTE: This is a RFC change which does not yet support
the CDX bus firmware interface as it is under development, and
this series aims to get an early feedback from the community.
There are TODO items mentioned in the patches which needs to
be updated for complete bus support.

Changes in v2: 
- introduce basic CDX bus infrastructure
- fixed code for making compatible visible for devices
  having the 'compatible' property only.
- moved CDX-MSI domain as part of CDX bus infrastructure
  (previously it was part of irqchip).
- fixed few prints
- support rescan and reset of CDX bus 
- add VFIO reset module for CDX bus based devices

Nipun Gupta (6):
  Documentation: DT: Add entry for CDX controller
  bus/cdx: add the cdx bus driver
  bus/cdx: add cdx-MSI domain with gic-its domain as parent
  bus/cdx: add rescan and reset support
  vfio: platform: reset: add reset for cdx devices
  driver core: add compatible string in sysfs for platform devices

 Documentation/ABI/testing/sysfs-bus-cdx       |  34 ++
 Documentation/ABI/testing/sysfs-bus-platform  |   8 +
 .../devicetree/bindings/bus/xlnx,cdx.yaml     | 110 +++++
 MAINTAINERS                                   |   8 +
 drivers/base/platform.c                       |  23 ++
 drivers/bus/Kconfig                           |   1 +
 drivers/bus/Makefile                          |   3 +
 drivers/bus/cdx/Kconfig                       |   7 +
 drivers/bus/cdx/Makefile                      |   3 +
 drivers/bus/cdx/cdx.c                         | 391 ++++++++++++++++++
 drivers/bus/cdx/cdx.h                         |  51 +++
 drivers/bus/cdx/cdx_msi_domain.c              |  90 ++++
 drivers/vfio/platform/reset/Kconfig           |   8 +
 drivers/vfio/platform/reset/Makefile          |   1 +
 .../vfio/platform/reset/vfio_platform_cdx.c   | 104 +++++
 include/linux/cdx/cdx_bus.h                   |  53 +++
 16 files changed, 895 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-cdx
 create mode 100644 Documentation/devicetree/bindings/bus/xlnx,cdx.yaml
 create mode 100644 drivers/bus/cdx/Kconfig
 create mode 100644 drivers/bus/cdx/Makefile
 create mode 100644 drivers/bus/cdx/cdx.c
 create mode 100644 drivers/bus/cdx/cdx.h
 create mode 100644 drivers/bus/cdx/cdx_msi_domain.c
 create mode 100644 drivers/vfio/platform/reset/vfio_platform_cdx.c
 create mode 100644 include/linux/cdx/cdx_bus.h

-- 
2.25.1