Merge tag 'cxl-for-5.14' of git://git.kernel.org/pub/scm/linux/kernel…

…/git/cxl/cxl

Pull CXL (Compute Express Link) updates from Dan Williams:
 "This subsystem is still in the build-out phase as the bulk of the
  update is improvements to enumeration and fleshing out the device
  model. In terms of new features, more mailbox commands have been added
  to the allowed-list in support of persistent memory provisioning
  support targeting v5.15.

  The critical update from an enumeration perspective is support for the
  CXL Fixed Memory Window Structure that indicates to Linux which system
  physical address ranges decode to the CXL Host Bridges in the system.
  This allows the driver to detect which address ranges have been mapped
  by firmware and what address ranges are available for future hotplug.

  So, again, mostly skeleton this round, with more meat targeting v5.15.

  Summary:

   - Add support for the CXL Fixed Memory Window Structure, a recent
     extension of the ACPI CEDT (CXL Early Discovery Table)

   - Add infrastructure for component registers

   - Add HDM (Host-managed device memory) decoder definitions

   - Define a device model for an HDM decoder tree

   - Bridge CXL persistent memory capabilities to an NVDIMM bus /
     device-model

   - Switch to fine grained mapping of CXL MMIO registers to allow
     different drivers / system software to own individual register
     blocks

   - Enable media provisioning commands, and publish the label storage
     area size in sysfs

   - Miscellaneous cleanups and fixes"

* tag 'cxl-for-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl: (34 commits)
  cxl/pci: Rename CXL REGLOC ID
  cxl/acpi: Use the ACPI CFMWS to create static decoder objects
  cxl/acpi: Add the Host Bridge base address to CXL port objects
  cxl/pmem: Register 'pmem' / cxl_nvdimm devices
  libnvdimm: Drop unused device power management support
  libnvdimm: Export nvdimm shutdown helper, nvdimm_delete()
  cxl/pmem: Add initial infrastructure for pmem support
  cxl/core: Add cxl-bus driver infrastructure
  cxl/pci: Add media provisioning required commands
  cxl/component_regs: Fix offset
  cxl/hdm: Fix decoder count calculation
  cxl/acpi: Introduce cxl_decoder objects
  cxl/acpi: Enumerate host bridge root ports
  cxl/acpi: Add downstream port data to cxl_port instances
  cxl/Kconfig: Default drivers to CONFIG_CXL_BUS
  cxl/acpi: Introduce the root of a cxl_port topology
  cxl/pci: Fixup devm_cxl_iomap_block() to take a 'struct device *'
  cxl/pci: Add HDM decoder capabilities
  cxl/pci: Reserve individual register block regions
  cxl/pci: Map registers based on capabilities
  ...

Documentation/ABI/testing/sysfs-bus-cxl

@@ -24,3 +24,106 @@ Description:
 		(RO) "Persistent Only Capacity" as bytes. Represents the
 		identically named field in the Identify Memory Device Output
 		Payload in the CXL-2.0 specification.
+
+What:		/sys/bus/cxl/devices/*/devtype
+Date:		June, 2021
+KernelVersion:	v5.14
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		CXL device objects export the devtype attribute which mirrors
+		the same value communicated in the DEVTYPE environment variable
+		for uevents for devices on the "cxl" bus.
+
+What:		/sys/bus/cxl/devices/portX/uport
+Date:		June, 2021
+KernelVersion:	v5.14
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		CXL port objects are enumerated from either a platform firmware
+		device (ACPI0017 and ACPI0016) or PCIe switch upstream port with
+		CXL component registers. The 'uport' symlink connects the CXL
+		portX object to the device that published the CXL port
+		capability.
+
+What:		/sys/bus/cxl/devices/portX/dportY
+Date:		June, 2021
+KernelVersion:	v5.14
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		CXL port objects are enumerated from either a platform firmware
+		device (ACPI0017 and ACPI0016) or PCIe switch upstream port with
+		CXL component registers. The 'dportY' symlink identifies one or
+		more downstream ports that the upstream port may target in its
+		decode of CXL memory resources.  The 'Y' integer reflects the
+		hardware port unique-id used in the hardware decoder target
+		list.
+
+What:		/sys/bus/cxl/devices/decoderX.Y
+Date:		June, 2021
+KernelVersion:	v5.14
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		CXL decoder objects are enumerated from either a platform
+		firmware description, or a CXL HDM decoder register set in a
+		PCIe device (see CXL 2.0 section 8.2.5.12 CXL HDM Decoder
+		Capability Structure). The 'X' in decoderX.Y represents the
+		cxl_port container of this decoder, and 'Y' represents the
+		instance id of a given decoder resource.
+
+What:		/sys/bus/cxl/devices/decoderX.Y/{start,size}
+Date:		June, 2021
+KernelVersion:	v5.14
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		The 'start' and 'size' attributes together convey the physical
+		address base and number of bytes mapped in the decoder's decode
+		window. For decoders of devtype "cxl_decoder_root" the address
+		range is fixed. For decoders of devtype "cxl_decoder_switch" the
+		address is bounded by the decode range of the cxl_port ancestor
+		of the decoder's cxl_port, and dynamically updates based on the
+		active memory regions in that address space.
+
+What:		/sys/bus/cxl/devices/decoderX.Y/locked
+Date:		June, 2021
+KernelVersion:	v5.14
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		CXL HDM decoders have the capability to lock the configuration
+		until the next device reset. For decoders of devtype
+		"cxl_decoder_root" there is no standard facility to unlock them.
+		For decoders of devtype "cxl_decoder_switch" a secondary bus
+		reset, of the PCIe bridge that provides the bus for this
+		decoders uport, unlocks / resets the decoder.
+
+What:		/sys/bus/cxl/devices/decoderX.Y/target_list
+Date:		June, 2021
+KernelVersion:	v5.14
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		Display a comma separated list of the current decoder target
+		configuration. The list is ordered by the current configured
+		interleave order of the decoder's dport instances. Each entry in
+		the list is a dport id.
+
+What:		/sys/bus/cxl/devices/decoderX.Y/cap_{pmem,ram,type2,type3}
+Date:		June, 2021
+KernelVersion:	v5.14
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		When a CXL decoder is of devtype "cxl_decoder_root", it
+		represents a fixed memory window identified by platform
+		firmware. A fixed window may only support a subset of memory
+		types. The 'cap_*' attributes indicate whether persistent
+		memory, volatile memory, accelerator memory, and / or expander
+		memory may be mapped behind this decoder's memory window.
+
+What:		/sys/bus/cxl/devices/decoderX.Y/target_type
+Date:		June, 2021
+KernelVersion:	v5.14
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		When a CXL decoder is of devtype "cxl_decoder_switch", it can
+		optionally decode either accelerator memory (type-2) or expander
+		memory (type-3). The 'target_type' attribute indicates the
+		current setting which may dynamically change based on what
+		memory regions are activated in this decode hierarchy.

Documentation/driver-api/cxl/memory-devices.rst

@@ -22,16 +22,22 @@ This section covers the driver infrastructure for a CXL memory device.
 CXL Memory Device
 -----------------
 
-.. kernel-doc:: drivers/cxl/mem.c
-   :doc: cxl mem
+.. kernel-doc:: drivers/cxl/pci.c
+   :doc: cxl pci
 
-.. kernel-doc:: drivers/cxl/mem.c
+.. kernel-doc:: drivers/cxl/pci.c
    :internal:
 
-CXL Bus
--------
-.. kernel-doc:: drivers/cxl/bus.c
-   :doc: cxl bus
+CXL Core
+--------
+.. kernel-doc:: drivers/cxl/cxl.h
+   :doc: cxl objects
+
+.. kernel-doc:: drivers/cxl/cxl.h
+   :internal:
+
+.. kernel-doc:: drivers/cxl/core.c
+   :doc: cxl core
 
 External Interfaces
 ===================

drivers/cxl/Kconfig

@@ -15,21 +15,17 @@ if CXL_BUS
 
 config CXL_MEM
 	tristate "CXL.mem: Memory Devices"
+	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 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.
+	  Say 'y/m' to enable a driver that will attach to CXL.mem devices 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'.
 
@@ -50,4 +46,33 @@ config CXL_MEM_RAW_COMMANDS
 	  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
+	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'.
 endif

drivers/cxl/Makefile

@@ -1,7 +1,11 @@
 # SPDX-License-Identifier: GPL-2.0
-obj-$(CONFIG_CXL_BUS) += cxl_bus.o
-obj-$(CONFIG_CXL_MEM) += cxl_mem.o
+obj-$(CONFIG_CXL_BUS) += cxl_core.o
+obj-$(CONFIG_CXL_MEM) += cxl_pci.o
+obj-$(CONFIG_CXL_ACPI) += cxl_acpi.o
+obj-$(CONFIG_CXL_PMEM) += cxl_pmem.o
 
 ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=CXL
-cxl_bus-y := bus.o
-cxl_mem-y := mem.o
+cxl_core-y := core.o
+cxl_pci-y := pci.o
+cxl_acpi-y := acpi.o
+cxl_pmem-y := pmem.o