[PATCH 0/5] cxl/dcd: Add support for Dynamic Capacity Devices (DCD)

[ira.weiny@intel.com]

I'm submitting these on behalf of Navneet.  There was a round of
internal discussion which left a few questions but we want to get the
public discussion going.  A first public preview was posted by Dan.[1]

The series has been rebased on the type-2 work posted from Dan.[2]  As
discussed in the community call, not all of that series is required for
these patches.  This will get rebased on the subset of those patches he
is targeting for 6.5.  The series was tested using Fan Ni's Qemu DCD
series.[3]

[cover letter]

A Dynamic Capacity Device (DCD) (CXL 3.0 spec 9.13.3) is a CXL memory
device that implements dynamic capacity.  Dynamic capacity feature
allows memory capacity to change dynamically, without the need for
resetting the device.

Provide initial patches to enable DCD on non interleaving regions.
Details:

- Get the dynamic capacity region information from cxl device and add
  the advertised DC memory to driver managed resources
- Get the device dynamic capacity extent list from the device and
  maintain it in the host and add the preallocated memory to the host
- Dynamic capacity region support
- DCD region provisioning via Dax
- Dynamic capacity event records
        a. Add capacity Events
	b. Release capacity events
	c. Add the memory to the host dc region
	d. Release the memory from the host dc region
- Trace Dynamic Capacity events
- Send add capacity response to device
- Send release dynamic capacity to device

Cc: Navneet Singh <navneet.singh@intel.com>
Cc: Fan Ni <fan.ni@samsung.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: linux-cxl@vger.kernel.org

[1] https://lore.kernel.org/all/64326437c1496_934b2949f@dwillia2-mobl3.amr.corp.intel.com.notmuch/
[2] https://lore.kernel.org/all/168592149709.1948938.8663425987110396027.stgit@dwillia2-xfh.jf.intel.com/
[3] https://lore.kernel.org/all/6483946e8152f_f1132294a2@iweiny-mobl.notmuch/

---
Navneet Singh (5):
      cxl/mem : Read Dynamic capacity configuration from the device
      cxl/region: Add dynamic capacity cxl region support.
      cxl/mem : Expose dynamic capacity configuration to userspace
      cxl/mem: Add support to handle DCD add and release capacity events.
      cxl/mem: Trace Dynamic capacity Event Record

 drivers/cxl/Kconfig       |  11 +
 drivers/cxl/core/core.h   |   7 +
 drivers/cxl/core/hdm.c    | 234 ++++++++++++++++++--
 drivers/cxl/core/mbox.c   | 540 +++++++++++++++++++++++++++++++++++++++++++++-
 drivers/cxl/core/memdev.c |  72 +++++++
 drivers/cxl/core/port.c   |  18 ++
 drivers/cxl/core/region.c | 337 ++++++++++++++++++++++++++++-
 drivers/cxl/core/trace.h  |  68 +++++-
 drivers/cxl/cxl.h         |  32 ++-
 drivers/cxl/cxlmem.h      | 146 ++++++++++++-
 drivers/cxl/pci.c         |  14 +-
 drivers/dax/bus.c         |  11 +-
 drivers/dax/bus.h         |   5 +-
 drivers/dax/cxl.c         |   4 +
 14 files changed, 1453 insertions(+), 46 deletions(-)
---
base-commit: 034a16d0165be3e092d60685be7b1b05e6f3059b
change-id: 20230604-dcd-type2-upstream-0cd15f6216fd

Best regards,
-- 
Ira Weiny <ira.weiny@intel.com>