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# SPDX-License-Identifier: GPL-2.0-only
menuconfig CXL_BUS
tristate "CXL (Compute Express Link) Devices Support"
depends on PCI
CXL is a bus that is electrically compatible with PCI Express, but
layers three protocols on that signalling (, 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 protocol is equivalent to PCI Express.
Say 'y' to enable support for the configuration and management of
devices supporting these protocols.
config CXL_MEM
tristate "CXL.mem: Memory Devices"
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
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'.
bool "RAW Command Interface for Memory Devices"
depends on CXL_MEM
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.