| # SPDX-License-Identifier: GPL-2.0-only | |
| menuconfig CXL_BUS | |
| tristate "CXL (Compute Express Link) Devices Support" | |
| depends on PCI | |
| select PCI_DOE | |
| help | |
| CXL is a bus that is electrically compatible with PCI Express, but | |
| layers three protocols on that signalling (CXL.io, CXL.cache, and | |
| CXL.mem). The CXL.cache protocol allows devices to hold cachelines | |
| locally, the CXL.mem protocol allows devices to be fully coherent | |
| memory targets, the CXL.io protocol is equivalent to PCI Express. | |
| Say 'y' to enable support for the configuration and management of | |
| devices supporting these protocols. | |
| if CXL_BUS | |
| config CXL_PCI | |
| tristate "PCI manageability" | |
| default CXL_BUS | |
| help | |
| The CXL specification defines a "CXL memory device" sub-class in the | |
| PCI "memory controller" base class of devices. Device's identified by | |
| this class code provide support for volatile and / or persistent | |
| memory to be mapped into the system address map (Host-managed Device | |
| Memory (HDM)). | |
| Say 'y/m' to enable a driver that will attach to CXL memory expander | |
| devices enumerated by the memory device class code for configuration | |
| and management primarily via the mailbox interface. See Chapter 2.3 | |
| Type 3 CXL Device in the CXL 2.0 specification for more details. | |
| If unsure say 'm'. | |
| config CXL_MEM_RAW_COMMANDS | |
| bool "RAW Command Interface for Memory Devices" | |
| depends on CXL_PCI | |
| help | |
| Enable CXL RAW command interface. | |
| The CXL driver ioctl interface may assign a kernel ioctl command | |
| number for each specification defined opcode. At any given point in | |
| time the number of opcodes that the specification defines and a device | |
| may implement may exceed the kernel's set of associated ioctl function | |
| numbers. The mismatch is either by omission, specification is too new, | |
| or by design. When prototyping new hardware, or developing / debugging | |
| the driver it is useful to be able to submit any possible command to | |
| the hardware, even commands that may crash the kernel due to their | |
| potential impact to memory currently in use by the kernel. | |
| If developing CXL hardware or the driver say Y, otherwise say N. | |
| config CXL_ACPI | |
| tristate "CXL ACPI: Platform Support" | |
| depends on ACPI | |
| default CXL_BUS | |
| select ACPI_TABLE_LIB | |
| help | |
| Enable support for host managed device memory (HDM) resources | |
| published by a platform's ACPI CXL memory layout description. See | |
| Chapter 9.14.1 CXL Early Discovery Table (CEDT) in the CXL 2.0 | |
| specification, and CXL Fixed Memory Window Structures (CEDT.CFMWS) | |
| (https://www.computeexpresslink.org/spec-landing). The CXL core | |
| consumes these resource to publish the root of a cxl_port decode | |
| hierarchy to map regions that represent System RAM, or Persistent | |
| Memory regions to be managed by LIBNVDIMM. | |
| If unsure say 'm'. | |
| config CXL_PMEM | |
| tristate "CXL PMEM: Persistent Memory Support" | |
| depends on LIBNVDIMM | |
| default CXL_BUS | |
| help | |
| In addition to typical memory resources a platform may also advertise | |
| support for persistent memory attached via CXL. This support is | |
| managed via a bridge driver from CXL to the LIBNVDIMM system | |
| subsystem. Say 'y/m' to enable support for enumerating and | |
| provisioning the persistent memory capacity of CXL memory expanders. | |
| If unsure say 'm'. | |
| config CXL_MEM | |
| tristate "CXL: Memory Expansion" | |
| depends on CXL_PCI | |
| default CXL_BUS | |
| help | |
| The CXL.mem protocol allows a device to act as a provider of "System | |
| RAM" and/or "Persistent Memory" that is fully coherent as if the | |
| memory were attached to the typical CPU memory controller. This is | |
| known as HDM "Host-managed Device Memory". | |
| Say 'y/m' to enable a driver that will attach to CXL.mem devices for | |
| memory expansion and control of HDM. See Chapter 9.13 in the CXL 2.0 | |
| specification for a detailed description of HDM. | |
| If unsure say 'm'. | |
| config CXL_PORT | |
| default CXL_BUS | |
| tristate | |
| config CXL_SUSPEND | |
| def_bool y | |
| depends on SUSPEND && CXL_MEM | |
| config CXL_REGION | |
| bool | |
| default CXL_BUS | |
| # For MAX_PHYSMEM_BITS | |
| depends on SPARSEMEM | |
| select MEMREGION | |
| select GET_FREE_REGION | |
| endif |