[0/6] Region creation

Message

Ben Widawsky June 17, 2021, 5:36 p.m. UTC

CXL interleave sets and non-interleave sets are described via regions. A region
is specified in the CXL 2.0 specification and the purpose is to create a
standardized way to preserve the region across reboots.

Introduced here is the basic mechanism to create configure and delete a CXL
region. Configuring a region simply means giving it a size, UUID, and a target
list. Enabling/activating a region is comprised of three parts:
1. Validate and find space for the region in the CFMWS (included here)
2. Program the HDM decoders (WIP)
3. Adding the region label to the LSA (Dan WIP)

Here is a sample topology

    decoder1.0
    ├── create_region
    ├── delete_region
    ├── devtype
    ├── locked
    ├── region1.0:0
    │   ├── offset
    │   ├── size
    │   ├── subsystem -> ../../../../../../../bus/cxl
    │   ├── target0
    │   ├── uevent
    │   ├── uuid
    │   └── verify
    ├── size
    ├── start
    ├── subsystem -> ../../../../../../bus/cxl
    ├── target_list
    ├── target_type
    └── uevent

Next Steps.
Next task is to create a CXL memory driver which will enumerate CXL capable
endpoints. A CXL capable endpoint is similar to the existing cxl_mem structure
except that it's known that there exists a path from a hostbridge down to the
endpoint that is CXL.mem capable. Once that path is established, the HDM decoder
programming can be determined from top of the hierarchy down.

Ben Widawsky (6):
  cxl/region: Add region creation ABI
  cxl: Move cxl_memdev conversion helper to mem.h
  cxl/region: Introduce concept of region configuration
  cxl/region: Introduce a cxl_region driver
  cxl/core: Convert decoder range to resource
  cxl/region: Handle region's address space allocation

 Documentation/ABI/testing/sysfs-bus-cxl       |  53 ++
 .../driver-api/cxl/memory-devices.rst         |  11 +
 drivers/cxl/Makefile                          |   5 +-
 drivers/cxl/core.c                            | 108 +++-
 drivers/cxl/cxl.h                             |  18 +-
 drivers/cxl/mem.h                             |   6 +
 drivers/cxl/pci.c                             |   5 -
 drivers/cxl/region.c                          | 492 ++++++++++++++++++
 drivers/cxl/region.h                          |  45 ++
 drivers/cxl/trace.h                           |  33 ++
 10 files changed, 760 insertions(+), 16 deletions(-)
 create mode 100644 drivers/cxl/region.c
 create mode 100644 drivers/cxl/region.h
 create mode 100644 drivers/cxl/trace.h