Merge tag 'cxl-for-6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl

Pull cxl updates from Dan Williams:
 "Compute Express Link (CXL) updates for 6.0:

   - Introduce a 'struct cxl_region' object with support for
     provisioning and assembling persistent memory regions.

   - Introduce alloc_free_mem_region() to accompany the existing
     request_free_mem_region() as a method to allocate physical memory
     capacity out of an existing resource.

   - Export insert_resource_expand_to_fit() for the CXL subsystem to
     late-publish CXL platform windows in iomem_resource.

   - Add a polled mode PCI DOE (Data Object Exchange) driver service and
     use it in cxl_pci to retrieve the CDAT (Coherent Device Attribute
     Table)"

* tag 'cxl-for-6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl: (74 commits)
  cxl/hdm: Fix skip allocations vs multiple pmem allocations
  cxl/region: Disallow region granularity != window granularity
  cxl/region: Fix x1 interleave to greater than x1 interleave routing
  cxl/region: Move HPA setup to cxl_region_attach()
  cxl/region: Fix decoder interleave programming
  Documentation: cxl: remove dangling kernel-doc reference
  cxl/region: describe targets and nr_targets members of cxl_region_params
  cxl/regions: add padding for cxl_rr_ep_add nested lists
  cxl/region: Fix IS_ERR() vs NULL check
  cxl/region: Fix region reference target accounting
  cxl/region: Fix region commit uninitialized variable warning
  cxl/region: Fix port setup uninitialized variable warnings
  cxl/region: Stop initializing interleave granularity
  cxl/hdm: Fix DPA reservation vs cxl_endpoint_decoder lifetime
  cxl/acpi: Minimize granularity for x1 interleaves
  cxl/region: Delete 'region' attribute from root decoders
  cxl/acpi: Autoload driver for 'cxl_acpi' test devices
  cxl/region: decrement ->nr_targets on error in cxl_region_attach()
  cxl/region: prevent underflow in ways_to_cxl()
  cxl/region: uninitialized variable in alloc_hpa()
  ...

1 files changed, 265 insertions, 40 deletions

diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl
index 7c2b846521f3..8494ef27e8d2 100644
--- a/Documentation/ABI/testing/sysfs-bus-cxl
+++ b/Documentation/ABI/testing/sysfs-bus-cxl
@@ -7,6 +7,7 @@ Description:
 		all descendant memdevs for unbind. Writing '1' to this attribute
 		flushes that work.
 
+
 What:		/sys/bus/cxl/devices/memX/firmware_version
 Date:		December, 2020
 KernelVersion:	v5.12
@@ -16,6 +17,7 @@ Description:
 		Memory Device Output Payload in the CXL-2.0
 		specification.
 
+
 What:		/sys/bus/cxl/devices/memX/ram/size
 Date:		December, 2020
 KernelVersion:	v5.12
@@ -25,6 +27,7 @@ Description:
 		identically named field in the Identify Memory Device Output
 		Payload in the CXL-2.0 specification.
 
+
 What:		/sys/bus/cxl/devices/memX/pmem/size
 Date:		December, 2020
 KernelVersion:	v5.12
@@ -34,6 +37,7 @@ Description:
 		identically named field in the Identify Memory Device Output
 		Payload in the CXL-2.0 specification.
 
+
 What:		/sys/bus/cxl/devices/memX/serial
 Date:		January, 2022
 KernelVersion:	v5.18
@@ -43,6 +47,7 @@ Description:
 		capability. Mandatory for CXL devices, see CXL 2.0 8.1.12.2
 		Memory Device PCIe Capabilities and Extended Capabilities.
 
+
 What:		/sys/bus/cxl/devices/memX/numa_node
 Date:		January, 2022
 KernelVersion:	v5.18
@@ -52,114 +57,334 @@ Description:
 		host PCI device for this memory device, emit the CPU node
 		affinity for this device.
 
+
 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.
+		(RO) 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/*/modalias
 Date:		December, 2021
 KernelVersion:	v5.18
 Contact:	linux-cxl@vger.kernel.org
 Description:
-		CXL device objects export the modalias attribute which mirrors
-		the same value communicated in the MODALIAS environment variable
-		for uevents for devices on the "cxl" bus.
+		(RO) CXL device objects export the modalias attribute which
+		mirrors the same value communicated in the MODALIAS 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
+		(RO) 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.
+		(RO) 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
+		(RO) 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.
+		(RO) 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.
+		(RO) 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.
+		(RO) 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
+		(RO) 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
+		(RO) 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.
+
+
+What:		/sys/bus/cxl/devices/endpointX/CDAT
+Date:		July, 2022
+KernelVersion:	v5.20
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(RO) If this sysfs entry is not present no DOE mailbox was
+		found to support CDAT data.  If it is present and the length of
+		the data is 0 reading the CDAT data failed.  Otherwise the CDAT
+		data is reported.
+
+
+What:		/sys/bus/cxl/devices/decoderX.Y/mode
+Date:		May, 2022
+KernelVersion:	v5.20
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(RW) When a CXL decoder is of devtype "cxl_decoder_endpoint" it
+		translates from a host physical address range, to a device local
+		address range. Device-local address ranges are further split
+		into a 'ram' (volatile memory) range and 'pmem' (persistent
+		memory) range. The 'mode' attribute emits one of 'ram', 'pmem',
+		'mixed', or 'none'. The 'mixed' indication is for error cases
+		when a decoder straddles the volatile/persistent partition
+		boundary, and 'none' indicates the decoder is not actively
+		decoding, or no DPA allocation policy has been set.
+
+		'mode' can be written, when the decoder is in the 'disabled'
+		state, with either 'ram' or 'pmem' to set the boundaries for the
+		next allocation.
+
+
+What:		/sys/bus/cxl/devices/decoderX.Y/dpa_resource
+Date:		May, 2022
+KernelVersion:	v5.20
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(RO) When a CXL decoder is of devtype "cxl_decoder_endpoint",
+		and its 'dpa_size' attribute is non-zero, this attribute
+		indicates the device physical address (DPA) base address of the
+		allocation.
+
+
+What:		/sys/bus/cxl/devices/decoderX.Y/dpa_size
+Date:		May, 2022
+KernelVersion:	v5.20
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(RW) When a CXL decoder is of devtype "cxl_decoder_endpoint" it
+		translates from a host physical address range, to a device local
+		address range. The range, base address plus length in bytes, of
+		DPA allocated to this decoder is conveyed in these 2 attributes.
+		Allocations can be mutated as long as the decoder is in the
+		disabled state. A write to 'dpa_size' releases the previous DPA
+		allocation and then attempts to allocate from the free capacity
+		in the device partition referred to by 'decoderX.Y/mode'.
+		Allocate and free requests can only be performed on the highest
+		instance number disabled decoder with non-zero size. I.e.
+		allocations are enforced to occur in increasing 'decoderX.Y/id'
+		order and frees are enforced to occur in decreasing
+		'decoderX.Y/id' order.
+
+
+What:		/sys/bus/cxl/devices/decoderX.Y/interleave_ways
+Date:		May, 2022
+KernelVersion:	v5.20
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(RO) The number of targets across which this decoder's host
+		physical address (HPA) memory range is interleaved. The device
+		maps every Nth block of HPA (of size ==
+		'interleave_granularity') to consecutive DPA addresses. The
+		decoder's position in the interleave is determined by the
+		device's (endpoint or switch) switch ancestry. For root
+		decoders their interleave is specified by platform firmware and
+		they only specify a downstream target order for host bridges.
+
+
+What:		/sys/bus/cxl/devices/decoderX.Y/interleave_granularity
+Date:		May, 2022
+KernelVersion:	v5.20
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(RO) The number of consecutive bytes of host physical address
+		space this decoder claims at address N before the decode rotates
+		to the next target in the interleave at address N +
+		interleave_granularity (assuming N is aligned to
+		interleave_granularity).
+
+
+What:		/sys/bus/cxl/devices/decoderX.Y/create_pmem_region
+Date:		May, 2022
+KernelVersion:	v5.20
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(RW) Write a string in the form 'regionZ' to start the process
+		of defining a new persistent memory region (interleave-set)
+		within the decode range bounded by root decoder 'decoderX.Y'.
+		The value written must match the current value returned from
+		reading this attribute. An atomic compare exchange operation is
+		done on write to assign the requested id to a region and
+		allocate the region-id for the next creation attempt. EBUSY is
+		returned if the region name written does not match the current
+		cached value.
+
+
+What:		/sys/bus/cxl/devices/decoderX.Y/delete_region
+Date:		May, 2022
+KernelVersion:	v5.20
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(WO) Write a string in the form 'regionZ' to delete that region,
+		provided it is currently idle / not bound to a driver.
+
+
+What:		/sys/bus/cxl/devices/regionZ/uuid
+Date:		May, 2022
+KernelVersion:	v5.20
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(RW) Write a unique identifier for the region. This field must
+		be set for persistent regions and it must not conflict with the
+		UUID of another region.
+
+
+What:		/sys/bus/cxl/devices/regionZ/interleave_granularity
+Date:		May, 2022
+KernelVersion:	v5.20
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(RW) Set the number of consecutive bytes each device in the
+		interleave set will claim. The possible interleave granularity
+		values are determined by the CXL spec and the participating
+		devices.
+
+
+What:		/sys/bus/cxl/devices/regionZ/interleave_ways
+Date:		May, 2022
+KernelVersion:	v5.20
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(RW) Configures the number of devices participating in the
+		region is set by writing this value. Each device will provide
+		1/interleave_ways of storage for the region.
+
+
+What:		/sys/bus/cxl/devices/regionZ/size
+Date:		May, 2022
+KernelVersion:	v5.20
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(RW) System physical address space to be consumed by the region.
+		When written trigger the driver to allocate space out of the
+		parent root decoder's address space. When read the size of the
+		address space is reported and should match the span of the
+		region's resource attribute. Size shall be set after the
+		interleave configuration parameters. Once set it cannot be
+		changed, only freed by writing 0. The kernel makes no guarantees
+		that data is maintained over an address space freeing event, and
+		there is no guarantee that a free followed by an allocate
+		results in the same address being allocated.
+
+
+What:		/sys/bus/cxl/devices/regionZ/resource
+Date:		May, 2022
+KernelVersion:	v5.20
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(RO) A region is a contiguous partition of a CXL root decoder
+		address space. Region capacity is allocated by writing to the
+		size attribute, the resulting physical address space determined
+		by the driver is reflected here. It is therefore not useful to
+		read this before writing a value to the size attribute.
+
+
+What:		/sys/bus/cxl/devices/regionZ/target[0..N]
+Date:		May, 2022
+KernelVersion:	v5.20
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(RW) Write an endpoint decoder object name to 'targetX' where X
+		is the intended position of the endpoint device in the region
+		interleave and N is the 'interleave_ways' setting for the
+		region. ENXIO is returned if the write results in an impossible
+		to map decode scenario, like the endpoint is unreachable at that
+		position relative to the root decoder interleave. EBUSY is
+		returned if the position in the region is already occupied, or
+		if the region is not in a state to accept interleave
+		configuration changes. EINVAL is returned if the object name is
+		not an endpoint decoder. Once all positions have been
+		successfully written a final validation for decode conflicts is
+		performed before activating the region.
+
+
+What:		/sys/bus/cxl/devices/regionZ/commit
+Date:		May, 2022
+KernelVersion:	v5.20
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(RW) Write a boolean 'true' string value to this attribute to
+		trigger the region to transition from the software programmed
+		state to the actively decoding in hardware state. The commit
+		operation in addition to validating that the region is in proper
+		configured state, validates that the decoders are being
+		committed in spec mandated order (last committed decoder id +
+		1), and checks that the hardware accepts the commit request.
+		Reading this value indicates whether the region is committed or
+		not.