cxl/mem: Read dynamic capacity configuration from the device

Devices which support Dynamic Capacity (DC) are configured via mailbox
commands. CXL r4.0 section 9.13.3 describes the use of the Get DC
Configuration command in order to obtain DCD partition characteristics.

Implement the DC mailbox commands as specified in CXL 4.0 section
8.2.10.9.9 (opcodes 48XXh) to read and store the DCD configuration
information. Disable DCD if an invalid configuration is found.

Initial enablement for Linux only supports one dynamic capacity
partition. Read all the partitions the device reports but validate
only the first, and configure it as 'dynamic ram'.

The specification requires that volatile capacity starts at DPA 0 and
pmem starts at the DPA immediately following it, but DC partitions only
need to be 256MB aligned according to CXL r4.0 section 8.2.10.9.9.1
Table 8-347. So a device could leave a gap between ram/pmem (static)
capacity and its first DC partition, or between one DC partition and
the next.

However, Linux chooses not to support gaps between static and dynamic
capacity, and requires the first DC partition to begin at the DPA
immediately following static capacity.

Based on an original patch by Navneet Singh.

[ dj: Fixed up output line wrapping. (Jonathan) ]
[ dj: Fixed up cleanup declaration. (Jonathan) ]
[ dj: Remove start_partition in cxl_get_dc_config. (Jonathan) ]

Signed-off-by: Ira Weiny <iweiny@kernel.org>
Co-developed-by: Anisa Su <anisa.su@samsung.com>
Signed-off-by: Anisa Su <anisa.su@samsung.com>
Tested-by: Wonjae Lee <wj28.lee@samsung.com>
Tested-by: Junhee Park <jh9934.park@samsung.com>
Tested-by: Heesoo Kim <habil.kim@samsung.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>
Link: https://patch.msgid.link/20261010225852.10727-3-anisa.su@samsung.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

0 files changed, 0 insertions, 0 deletions