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| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-cxl | 390 |
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diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl new file mode 100644 index 000000000000..8494ef27e8d2 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-cxl @@ -0,0 +1,390 @@ +What: /sys/bus/cxl/flush +Date: Januarry, 2022 +KernelVersion: v5.18 +Contact: linux-cxl@vger.kernel.org +Description: + (WO) If userspace manually unbinds a port the kernel schedules + 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 +Contact: linux-cxl@vger.kernel.org +Description: + (RO) "FW Revision" string as reported by the Identify + Memory Device Output Payload in the CXL-2.0 + specification. + + +What: /sys/bus/cxl/devices/memX/ram/size +Date: December, 2020 +KernelVersion: v5.12 +Contact: linux-cxl@vger.kernel.org +Description: + (RO) "Volatile 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/memX/pmem/size +Date: December, 2020 +KernelVersion: v5.12 +Contact: linux-cxl@vger.kernel.org +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/memX/serial +Date: January, 2022 +KernelVersion: v5.18 +Contact: linux-cxl@vger.kernel.org +Description: + (RO) 64-bit serial number per the PCIe Device Serial Number + 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 +Contact: linux-cxl@vger.kernel.org +Description: + (RO) If NUMA is enabled and the platform has affinitized the + 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: + (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: + (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: + (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: + (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: + (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: + (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: + (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: + (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: + (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: + (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. |