Linux kernel mirror (for testing)
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linux
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 help
19 The CXL.mem protocol allows a device to act as a provider of
20 "System RAM" and/or "Persistent Memory" that is fully coherent
21 as if the memory was attached to the typical CPU memory
22 controller.
23
24 Say 'y/m' to enable a driver (named "cxl_mem.ko" when built as
25 a module) that will attach to CXL.mem devices for
26 configuration, provisioning, and health monitoring. This
27 driver is required for dynamic provisioning of CXL.mem
28 attached memory which is a prerequisite for persistent memory
29 support. Typically volatile memory is mapped by platform
30 firmware and included in the platform memory map, but in some
31 cases the OS is responsible for mapping that memory. See
32 Chapter 2.3 Type 3 CXL Device in the CXL 2.0 specification.
33
34 If unsure say 'm'.
35
36config CXL_MEM_RAW_COMMANDS
37 bool "RAW Command Interface for Memory Devices"
38 depends on CXL_MEM
39 help
40 Enable CXL RAW command interface.
41
42 The CXL driver ioctl interface may assign a kernel ioctl command
43 number for each specification defined opcode. At any given point in
44 time the number of opcodes that the specification defines and a device
45 may implement may exceed the kernel's set of associated ioctl function
46 numbers. The mismatch is either by omission, specification is too new,
47 or by design. When prototyping new hardware, or developing / debugging
48 the driver it is useful to be able to submit any possible command to
49 the hardware, even commands that may crash the kernel due to their
50 potential impact to memory currently in use by the kernel.
51
52 If developing CXL hardware or the driver say Y, otherwise say N.
53endif