1# SPDX-License-Identifier: GPL-2.0-only 2menuconfig CXL_BUS 3 tristate "CXL (Compute Express Link) Devices Support" 4 depends on PCI 5 help 6 CXL is a bus that is electrically compatible with PCI Express, but 7 layers three protocols on that signalling (CXL.io, CXL.cache, and 8 CXL.mem). The CXL.cache protocol allows devices to hold cachelines 9 locally, the CXL.mem protocol allows devices to be fully coherent 10 memory targets, the CXL.io protocol is equivalent to PCI Express. 11 Say 'y' to enable support for the configuration and management of 12 devices supporting these protocols. 13 14if CXL_BUS 15 16config CXL_MEM 17 tristate "CXL.mem: Memory Devices" 18 default CXL_BUS 19 help 20 The CXL.mem protocol allows a device to act as a provider of 21 "System RAM" and/or "Persistent Memory" that is fully coherent 22 as if the memory was attached to the typical CPU memory 23 controller. 24 25 Say 'y/m' to enable a driver that will attach to CXL.mem devices for 26 configuration and management primarily via the mailbox interface. See 27 Chapter 2.3 Type 3 CXL Device in the CXL 2.0 specification for more 28 details. 29 30 If unsure say 'm'. 31 32config CXL_MEM_RAW_COMMANDS 33 bool "RAW Command Interface for Memory Devices" 34 depends on CXL_MEM 35 help 36 Enable CXL RAW command interface. 37 38 The CXL driver ioctl interface may assign a kernel ioctl command 39 number for each specification defined opcode. At any given point in 40 time the number of opcodes that the specification defines and a device 41 may implement may exceed the kernel's set of associated ioctl function 42 numbers. The mismatch is either by omission, specification is too new, 43 or by design. When prototyping new hardware, or developing / debugging 44 the driver it is useful to be able to submit any possible command to 45 the hardware, even commands that may crash the kernel due to their 46 potential impact to memory currently in use by the kernel. 47 48 If developing CXL hardware or the driver say Y, otherwise say N. 49 50config CXL_ACPI 51 tristate "CXL ACPI: Platform Support" 52 depends on ACPI 53 default CXL_BUS 54 select ACPI_TABLE_LIB 55 help 56 Enable support for host managed device memory (HDM) resources 57 published by a platform's ACPI CXL memory layout description. See 58 Chapter 9.14.1 CXL Early Discovery Table (CEDT) in the CXL 2.0 59 specification, and CXL Fixed Memory Window Structures (CEDT.CFMWS) 60 (https://www.computeexpresslink.org/spec-landing). The CXL core 61 consumes these resource to publish the root of a cxl_port decode 62 hierarchy to map regions that represent System RAM, or Persistent 63 Memory regions to be managed by LIBNVDIMM. 64 65 If unsure say 'm'. 66 67config CXL_PMEM 68 tristate "CXL PMEM: Persistent Memory Support" 69 depends on LIBNVDIMM 70 default CXL_BUS 71 help 72 In addition to typical memory resources a platform may also advertise 73 support for persistent memory attached via CXL. This support is 74 managed via a bridge driver from CXL to the LIBNVDIMM system 75 subsystem. Say 'y/m' to enable support for enumerating and 76 provisioning the persistent memory capacity of CXL memory expanders. 77 78 If unsure say 'm'. 79endif 80