| # SPDX-License-Identifier: GPL-2.0-only |
| menuconfig CXL_BUS |
| tristate "CXL (Compute Express Link) Devices Support" |
| depends on PCI |
| 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_MEM |
| tristate "CXL.mem: Memory Devices" |
| 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 was attached to the typical CPU memory |
| controller. |
| |
| Say 'y/m' to enable a driver (named "cxl_mem.ko" when built as |
| a module) that will attach to CXL.mem devices for |
| configuration, provisioning, and health monitoring. This |
| driver is required for dynamic provisioning of CXL.mem |
| attached memory which is a prerequisite for persistent memory |
| support. Typically volatile memory is mapped by platform |
| firmware and included in the platform memory map, but in some |
| cases the OS is responsible for mapping that memory. See |
| Chapter 2.3 Type 3 CXL Device in the CXL 2.0 specification. |
| |
| If unsure say 'm'. |
| |
| config CXL_MEM_RAW_COMMANDS |
| bool "RAW Command Interface for Memory Devices" |
| depends on CXL_MEM |
| 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. |
| endif |