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linux/Documentation/ABI/testing/sysfs-bus-cxl

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cxl/mem: Add the cxl_mem driver At this point the subsystem can enumerate all CXL ports (CXL.mem decode resources in upstream switch ports and host bridges) in a system. The last mile is connecting those ports to endpoints. The cxl_mem driver connects an endpoint device to the platform CXL.mem protoctol decode-topology. At ->probe() time it walks its device-topology-ancestry and adds a CXL Port object at every Upstream Port hop until it gets to CXL root. The CXL root object is only present after a platform firmware driver registers platform CXL resources. For ACPI based platform this is managed by the ACPI0017 device and the cxl_acpi driver. The ports are registered such that disabling a given port automatically unregisters all descendant ports, and the chain can only be registered after the root is established. Given ACPI device scanning may run asynchronously compared to PCI device scanning the root driver is tasked with rescanning the bus after the root successfully probes. Conversely if any ports in a chain between the root and an endpoint becomes disconnected it subsequently triggers the endpoint to unregister. Given lock depenedencies the endpoint unregistration happens in a workqueue asynchronously. If userspace cares about synchronizing delayed work after port events the /sys/bus/cxl/flush attribute is available for that purpose. Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> [djbw: clarify changelog, rework hotplug support] Link: https://lore.kernel.org/r/164398782997.903003.9725273241627693186.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-02-04 07:18:31 -08:00
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.
cxl/mem: Register CXL memX devices Create the /sys/bus/cxl hierarchy to enumerate: * Memory Devices (per-endpoint control devices) * Memory Address Space Devices (platform address ranges with interleaving, performance, and persistence attributes) * Memory Regions (active provisioned memory from an address space device that is in use as System RAM or delegated to libnvdimm as Persistent Memory regions). For now, only the per-endpoint control devices are registered on the 'cxl' bus. However, going forward it will provide a mechanism to coordinate cross-device interleave. Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> (v2) Link: https://lore.kernel.org/r/20210217040958.1354670-4-ben.widawsky@intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-02-16 20:09:52 -08:00
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.
cxl/acpi: Introduce the root of a cxl_port topology While CXL builds upon the PCI software model for enumeration and endpoint control, a static platform component is required to bootstrap the CXL memory layout. Similar to how ACPI identifies root-level PCI memory resources, ACPI data enumerates the address space and interleave configuration for CXL Memory. In addition to identifying host bridges, ACPI is responsible for enumerating the CXL memory space that can be addressed by downstream decoders. This is similar to the requirement for ACPI to publish resources via the _CRS method for PCI host bridges. Specifically, ACPI publishes a table, CXL Early Discovery Table (CEDT), which includes a list of CXL Memory resources, CXL Fixed Memory Window Structures (CFMWS). For now, introduce the core infrastructure for a cxl_port hierarchy starting with a root level anchor represented by the ACPI0017 device. Follow on changes model support for the configurable decode capabilities of cxl_port instances, i.e. CXL switch support. Co-developed-by: Alison Schofield <alison.schofield@intel.com> Signed-off-by: Alison Schofield <alison.schofield@intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/162325449515.2293126.15303270193010154608.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-09 09:01:35 -07:00
cxl/pci: Emit device serial number Per the CXL specification (8.1.12.2 Memory Device PCIe Capabilities and Extended Capabilities) the Device Serial Number capability is mandatory. Emit it for user tooling to identify devices. It is reasonable to ask whether the attribute should be added to the list of PCI sysfs device attributes. The PCI layer can optionally emit it too, but the CXL subsystem is aiming to preserve its independence and the possibility of CXL topologies with non-PCI devices in it. To date that has only proven useful for the 'cxl_test' model, but as can be seen with seen with ACPI0016 devices, sometimes all that is needed is a platform firmware table to point to CXL Component Registers in MMIO space to define a "CXL" device. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/164366608838.196598.16856227191534267098.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-01-31 13:56:11 -08:00
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.
cxl/memdev: Add numa_node attribute While CXL memory targets will have their own memory target node, individual memory devices may be affinitized like other PCI devices. Emit that attribute for memdevs. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/164298428430.3018233.16409089892707993289.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-01-23 16:31:24 -08:00
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.
cxl/acpi: Introduce the root of a cxl_port topology While CXL builds upon the PCI software model for enumeration and endpoint control, a static platform component is required to bootstrap the CXL memory layout. Similar to how ACPI identifies root-level PCI memory resources, ACPI data enumerates the address space and interleave configuration for CXL Memory. In addition to identifying host bridges, ACPI is responsible for enumerating the CXL memory space that can be addressed by downstream decoders. This is similar to the requirement for ACPI to publish resources via the _CRS method for PCI host bridges. Specifically, ACPI publishes a table, CXL Early Discovery Table (CEDT), which includes a list of CXL Memory resources, CXL Fixed Memory Window Structures (CFMWS). For now, introduce the core infrastructure for a cxl_port hierarchy starting with a root level anchor represented by the ACPI0017 device. Follow on changes model support for the configurable decode capabilities of cxl_port instances, i.e. CXL switch support. Co-developed-by: Alison Schofield <alison.schofield@intel.com> Signed-off-by: Alison Schofield <alison.schofield@intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/162325449515.2293126.15303270193010154608.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-09 09:01:35 -07:00
What: /sys/bus/cxl/devices/*/devtype
Date: June, 2021
KernelVersion: v5.14
Contact: linux-cxl@vger.kernel.org
Description:
cxl/Documentation: List attribute permissions Clarify the access permission of CXL sysfs attributes in the documentation to help development of userspace tooling. Reported-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/165603881198.551046.12893348287451903699.stgit@dwillia2-xfh Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-06-21 17:23:16 -07:00
(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.
cxl/acpi: Introduce the root of a cxl_port topology While CXL builds upon the PCI software model for enumeration and endpoint control, a static platform component is required to bootstrap the CXL memory layout. Similar to how ACPI identifies root-level PCI memory resources, ACPI data enumerates the address space and interleave configuration for CXL Memory. In addition to identifying host bridges, ACPI is responsible for enumerating the CXL memory space that can be addressed by downstream decoders. This is similar to the requirement for ACPI to publish resources via the _CRS method for PCI host bridges. Specifically, ACPI publishes a table, CXL Early Discovery Table (CEDT), which includes a list of CXL Memory resources, CXL Fixed Memory Window Structures (CFMWS). For now, introduce the core infrastructure for a cxl_port hierarchy starting with a root level anchor represented by the ACPI0017 device. Follow on changes model support for the configurable decode capabilities of cxl_port instances, i.e. CXL switch support. Co-developed-by: Alison Schofield <alison.schofield@intel.com> Signed-off-by: Alison Schofield <alison.schofield@intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/162325449515.2293126.15303270193010154608.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-09 09:01:35 -07:00
cxl/core: Emit modalias for CXL devices In order to enable libkmod lookups for CXL device objects to their corresponding module, add 'modalias' to the base attribute of CXL devices. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Ben Widawsky <ben.widawsky@intel.com> Link: https://lore.kernel.org/r/164298424120.3018233.15611905873808708542.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-01-23 16:30:41 -08:00
What: /sys/bus/cxl/devices/*/modalias
Date: December, 2021
KernelVersion: v5.18
Contact: linux-cxl@vger.kernel.org
Description:
cxl/Documentation: List attribute permissions Clarify the access permission of CXL sysfs attributes in the documentation to help development of userspace tooling. Reported-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/165603881198.551046.12893348287451903699.stgit@dwillia2-xfh Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-06-21 17:23:16 -07:00
(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.
cxl/core: Emit modalias for CXL devices In order to enable libkmod lookups for CXL device objects to their corresponding module, add 'modalias' to the base attribute of CXL devices. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Ben Widawsky <ben.widawsky@intel.com> Link: https://lore.kernel.org/r/164298424120.3018233.15611905873808708542.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-01-23 16:30:41 -08:00
cxl/acpi: Introduce the root of a cxl_port topology While CXL builds upon the PCI software model for enumeration and endpoint control, a static platform component is required to bootstrap the CXL memory layout. Similar to how ACPI identifies root-level PCI memory resources, ACPI data enumerates the address space and interleave configuration for CXL Memory. In addition to identifying host bridges, ACPI is responsible for enumerating the CXL memory space that can be addressed by downstream decoders. This is similar to the requirement for ACPI to publish resources via the _CRS method for PCI host bridges. Specifically, ACPI publishes a table, CXL Early Discovery Table (CEDT), which includes a list of CXL Memory resources, CXL Fixed Memory Window Structures (CFMWS). For now, introduce the core infrastructure for a cxl_port hierarchy starting with a root level anchor represented by the ACPI0017 device. Follow on changes model support for the configurable decode capabilities of cxl_port instances, i.e. CXL switch support. Co-developed-by: Alison Schofield <alison.schofield@intel.com> Signed-off-by: Alison Schofield <alison.schofield@intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/162325449515.2293126.15303270193010154608.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-09 09:01:35 -07:00
What: /sys/bus/cxl/devices/portX/uport
Date: June, 2021
KernelVersion: v5.14
Contact: linux-cxl@vger.kernel.org
Description:
cxl/Documentation: List attribute permissions Clarify the access permission of CXL sysfs attributes in the documentation to help development of userspace tooling. Reported-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/165603881198.551046.12893348287451903699.stgit@dwillia2-xfh Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-06-21 17:23:16 -07:00
(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
cxl/acpi: Introduce the root of a cxl_port topology While CXL builds upon the PCI software model for enumeration and endpoint control, a static platform component is required to bootstrap the CXL memory layout. Similar to how ACPI identifies root-level PCI memory resources, ACPI data enumerates the address space and interleave configuration for CXL Memory. In addition to identifying host bridges, ACPI is responsible for enumerating the CXL memory space that can be addressed by downstream decoders. This is similar to the requirement for ACPI to publish resources via the _CRS method for PCI host bridges. Specifically, ACPI publishes a table, CXL Early Discovery Table (CEDT), which includes a list of CXL Memory resources, CXL Fixed Memory Window Structures (CFMWS). For now, introduce the core infrastructure for a cxl_port hierarchy starting with a root level anchor represented by the ACPI0017 device. Follow on changes model support for the configurable decode capabilities of cxl_port instances, i.e. CXL switch support. Co-developed-by: Alison Schofield <alison.schofield@intel.com> Signed-off-by: Alison Schofield <alison.schofield@intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/162325449515.2293126.15303270193010154608.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-09 09:01:35 -07:00
capability.
cxl/acpi: Add downstream port data to cxl_port instances In preparation for infrastructure that enumerates and configures the CXL decode mechanism of an upstream port to its downstream ports, add a representation of a CXL downstream port. On ACPI systems the top-most logical downstream ports in the hierarchy are the host bridges (ACPI0016 devices) that decode the memory windows described by the CXL Early Discovery Table Fixed Memory Window Structures (CEDT.CFMWS). Reviewed-by: Alison Schofield <alison.schofield@intel.com> Link: https://lore.kernel.org/r/162325450624.2293126.3533006409920271718.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-09 09:01:46 -07:00
What: /sys/bus/cxl/devices/portX/dportY
Date: June, 2021
KernelVersion: v5.14
Contact: linux-cxl@vger.kernel.org
Description:
cxl/Documentation: List attribute permissions Clarify the access permission of CXL sysfs attributes in the documentation to help development of userspace tooling. Reported-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/165603881198.551046.12893348287451903699.stgit@dwillia2-xfh Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-06-21 17:23:16 -07:00
(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.
cxl/acpi: Introduce cxl_decoder objects A cxl_decoder is a child of a cxl_port. It represents a hardware decoder configuration of an upstream port to one or more of its downstream ports. The decoder is either represented in CXL standard HDM decoder registers (see CXL 2.0 section 8.2.5.12 CXL HDM Decoder Capability Structure), or it is a static decode configuration communicated by platform firmware (see the CXL Early Discovery Table: Fixed Memory Window Structure). The firmware described and hardware described decoders differ slightly leading to 2 different sub-types of decoders, cxl_decoder_root and cxl_decoder_switch. At the root level the decode capabilities restrict what can be mapped beneath them. Mid-level switch decoders are configured for either acclerator (type-2) or memory-expander (type-3) operation, but they are otherwise agnostic to the type of memory (volatile vs persistent) being mapped. Here is an example topology from a single-ported host-bridge environment without CFMWS decodes enumerated. /sys/bus/cxl/devices/root0 ├── devtype ├── dport0 -> ../../../LNXSYSTM:00/LNXSYBUS:00/ACPI0016:00 ├── port1 │   ├── decoder1.0 │   │   ├── devtype │   │   ├── locked │   │   ├── size │   │   ├── start │   │   ├── subsystem -> ../../../../../../bus/cxl │   │   ├── target_list │   │   ├── target_type │   │   └── uevent │   ├── devtype │   ├── dport0 -> ../../../../pci0000:34/0000:34:00.0 │   ├── subsystem -> ../../../../../bus/cxl │   ├── uevent │   └── uport -> ../../../../LNXSYSTM:00/LNXSYBUS:00/ACPI0016:00 ├── subsystem -> ../../../../bus/cxl ├── uevent └── uport -> ../../ACPI0017:00 Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/162325695128.2293823.17519927266014762694.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-09 09:43:29 -07:00
What: /sys/bus/cxl/devices/decoderX.Y
Date: June, 2021
KernelVersion: v5.14
Contact: linux-cxl@vger.kernel.org
Description:
cxl/Documentation: List attribute permissions Clarify the access permission of CXL sysfs attributes in the documentation to help development of userspace tooling. Reported-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/165603881198.551046.12893348287451903699.stgit@dwillia2-xfh Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-06-21 17:23:16 -07:00
(RO) CXL decoder objects are enumerated from either a platform
cxl/acpi: Introduce cxl_decoder objects A cxl_decoder is a child of a cxl_port. It represents a hardware decoder configuration of an upstream port to one or more of its downstream ports. The decoder is either represented in CXL standard HDM decoder registers (see CXL 2.0 section 8.2.5.12 CXL HDM Decoder Capability Structure), or it is a static decode configuration communicated by platform firmware (see the CXL Early Discovery Table: Fixed Memory Window Structure). The firmware described and hardware described decoders differ slightly leading to 2 different sub-types of decoders, cxl_decoder_root and cxl_decoder_switch. At the root level the decode capabilities restrict what can be mapped beneath them. Mid-level switch decoders are configured for either acclerator (type-2) or memory-expander (type-3) operation, but they are otherwise agnostic to the type of memory (volatile vs persistent) being mapped. Here is an example topology from a single-ported host-bridge environment without CFMWS decodes enumerated. /sys/bus/cxl/devices/root0 ├── devtype ├── dport0 -> ../../../LNXSYSTM:00/LNXSYBUS:00/ACPI0016:00 ├── port1 │   ├── decoder1.0 │   │   ├── devtype │   │   ├── locked │   │   ├── size │   │   ├── start │   │   ├── subsystem -> ../../../../../../bus/cxl │   │   ├── target_list │   │   ├── target_type │   │   └── uevent │   ├── devtype │   ├── dport0 -> ../../../../pci0000:34/0000:34:00.0 │   ├── subsystem -> ../../../../../bus/cxl │   ├── uevent │   └── uport -> ../../../../LNXSYSTM:00/LNXSYBUS:00/ACPI0016:00 ├── subsystem -> ../../../../bus/cxl ├── uevent └── uport -> ../../ACPI0017:00 Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/162325695128.2293823.17519927266014762694.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-09 09:43:29 -07:00
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:
cxl/Documentation: List attribute permissions Clarify the access permission of CXL sysfs attributes in the documentation to help development of userspace tooling. Reported-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/165603881198.551046.12893348287451903699.stgit@dwillia2-xfh Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-06-21 17:23:16 -07:00
(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.
cxl/acpi: Introduce cxl_decoder objects A cxl_decoder is a child of a cxl_port. It represents a hardware decoder configuration of an upstream port to one or more of its downstream ports. The decoder is either represented in CXL standard HDM decoder registers (see CXL 2.0 section 8.2.5.12 CXL HDM Decoder Capability Structure), or it is a static decode configuration communicated by platform firmware (see the CXL Early Discovery Table: Fixed Memory Window Structure). The firmware described and hardware described decoders differ slightly leading to 2 different sub-types of decoders, cxl_decoder_root and cxl_decoder_switch. At the root level the decode capabilities restrict what can be mapped beneath them. Mid-level switch decoders are configured for either acclerator (type-2) or memory-expander (type-3) operation, but they are otherwise agnostic to the type of memory (volatile vs persistent) being mapped. Here is an example topology from a single-ported host-bridge environment without CFMWS decodes enumerated. /sys/bus/cxl/devices/root0 ├── devtype ├── dport0 -> ../../../LNXSYSTM:00/LNXSYBUS:00/ACPI0016:00 ├── port1 │   ├── decoder1.0 │   │   ├── devtype │   │   ├── locked │   │   ├── size │   │   ├── start │   │   ├── subsystem -> ../../../../../../bus/cxl │   │   ├── target_list │   │   ├── target_type │   │   └── uevent │   ├── devtype │   ├── dport0 -> ../../../../pci0000:34/0000:34:00.0 │   ├── subsystem -> ../../../../../bus/cxl │   ├── uevent │   └── uport -> ../../../../LNXSYSTM:00/LNXSYBUS:00/ACPI0016:00 ├── subsystem -> ../../../../bus/cxl ├── uevent └── uport -> ../../ACPI0017:00 Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/162325695128.2293823.17519927266014762694.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-09 09:43:29 -07:00
What: /sys/bus/cxl/devices/decoderX.Y/locked
Date: June, 2021
KernelVersion: v5.14
Contact: linux-cxl@vger.kernel.org
Description:
cxl/Documentation: List attribute permissions Clarify the access permission of CXL sysfs attributes in the documentation to help development of userspace tooling. Reported-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/165603881198.551046.12893348287451903699.stgit@dwillia2-xfh Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-06-21 17:23:16 -07:00
(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.
cxl/acpi: Introduce cxl_decoder objects A cxl_decoder is a child of a cxl_port. It represents a hardware decoder configuration of an upstream port to one or more of its downstream ports. The decoder is either represented in CXL standard HDM decoder registers (see CXL 2.0 section 8.2.5.12 CXL HDM Decoder Capability Structure), or it is a static decode configuration communicated by platform firmware (see the CXL Early Discovery Table: Fixed Memory Window Structure). The firmware described and hardware described decoders differ slightly leading to 2 different sub-types of decoders, cxl_decoder_root and cxl_decoder_switch. At the root level the decode capabilities restrict what can be mapped beneath them. Mid-level switch decoders are configured for either acclerator (type-2) or memory-expander (type-3) operation, but they are otherwise agnostic to the type of memory (volatile vs persistent) being mapped. Here is an example topology from a single-ported host-bridge environment without CFMWS decodes enumerated. /sys/bus/cxl/devices/root0 ├── devtype ├── dport0 -> ../../../LNXSYSTM:00/LNXSYBUS:00/ACPI0016:00 ├── port1 │   ├── decoder1.0 │   │   ├── devtype │   │   ├── locked │   │   ├── size │   │   ├── start │   │   ├── subsystem -> ../../../../../../bus/cxl │   │   ├── target_list │   │   ├── target_type │   │   └── uevent │   ├── devtype │   ├── dport0 -> ../../../../pci0000:34/0000:34:00.0 │   ├── subsystem -> ../../../../../bus/cxl │   ├── uevent │   └── uport -> ../../../../LNXSYSTM:00/LNXSYBUS:00/ACPI0016:00 ├── subsystem -> ../../../../bus/cxl ├── uevent └── uport -> ../../ACPI0017:00 Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/162325695128.2293823.17519927266014762694.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-09 09:43:29 -07:00
What: /sys/bus/cxl/devices/decoderX.Y/target_list
Date: June, 2021
KernelVersion: v5.14
Contact: linux-cxl@vger.kernel.org
Description:
cxl/Documentation: List attribute permissions Clarify the access permission of CXL sysfs attributes in the documentation to help development of userspace tooling. Reported-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/165603881198.551046.12893348287451903699.stgit@dwillia2-xfh Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-06-21 17:23:16 -07:00
(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.
cxl/acpi: Introduce cxl_decoder objects A cxl_decoder is a child of a cxl_port. It represents a hardware decoder configuration of an upstream port to one or more of its downstream ports. The decoder is either represented in CXL standard HDM decoder registers (see CXL 2.0 section 8.2.5.12 CXL HDM Decoder Capability Structure), or it is a static decode configuration communicated by platform firmware (see the CXL Early Discovery Table: Fixed Memory Window Structure). The firmware described and hardware described decoders differ slightly leading to 2 different sub-types of decoders, cxl_decoder_root and cxl_decoder_switch. At the root level the decode capabilities restrict what can be mapped beneath them. Mid-level switch decoders are configured for either acclerator (type-2) or memory-expander (type-3) operation, but they are otherwise agnostic to the type of memory (volatile vs persistent) being mapped. Here is an example topology from a single-ported host-bridge environment without CFMWS decodes enumerated. /sys/bus/cxl/devices/root0 ├── devtype ├── dport0 -> ../../../LNXSYSTM:00/LNXSYBUS:00/ACPI0016:00 ├── port1 │   ├── decoder1.0 │   │   ├── devtype │   │   ├── locked │   │   ├── size │   │   ├── start │   │   ├── subsystem -> ../../../../../../bus/cxl │   │   ├── target_list │   │   ├── target_type │   │   └── uevent │   ├── devtype │   ├── dport0 -> ../../../../pci0000:34/0000:34:00.0 │   ├── subsystem -> ../../../../../bus/cxl │   ├── uevent │   └── uport -> ../../../../LNXSYSTM:00/LNXSYBUS:00/ACPI0016:00 ├── subsystem -> ../../../../bus/cxl ├── uevent └── uport -> ../../ACPI0017:00 Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/162325695128.2293823.17519927266014762694.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-09 09:43:29 -07:00
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:
cxl/Documentation: List attribute permissions Clarify the access permission of CXL sysfs attributes in the documentation to help development of userspace tooling. Reported-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/165603881198.551046.12893348287451903699.stgit@dwillia2-xfh Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-06-21 17:23:16 -07:00
(RO) When a CXL decoder is of devtype "cxl_decoder_root", it
cxl/acpi: Introduce cxl_decoder objects A cxl_decoder is a child of a cxl_port. It represents a hardware decoder configuration of an upstream port to one or more of its downstream ports. The decoder is either represented in CXL standard HDM decoder registers (see CXL 2.0 section 8.2.5.12 CXL HDM Decoder Capability Structure), or it is a static decode configuration communicated by platform firmware (see the CXL Early Discovery Table: Fixed Memory Window Structure). The firmware described and hardware described decoders differ slightly leading to 2 different sub-types of decoders, cxl_decoder_root and cxl_decoder_switch. At the root level the decode capabilities restrict what can be mapped beneath them. Mid-level switch decoders are configured for either acclerator (type-2) or memory-expander (type-3) operation, but they are otherwise agnostic to the type of memory (volatile vs persistent) being mapped. Here is an example topology from a single-ported host-bridge environment without CFMWS decodes enumerated. /sys/bus/cxl/devices/root0 ├── devtype ├── dport0 -> ../../../LNXSYSTM:00/LNXSYBUS:00/ACPI0016:00 ├── port1 │   ├── decoder1.0 │   │   ├── devtype │   │   ├── locked │   │   ├── size │   │   ├── start │   │   ├── subsystem -> ../../../../../../bus/cxl │   │   ├── target_list │   │   ├── target_type │   │   └── uevent │   ├── devtype │   ├── dport0 -> ../../../../pci0000:34/0000:34:00.0 │   ├── subsystem -> ../../../../../bus/cxl │   ├── uevent │   └── uport -> ../../../../LNXSYSTM:00/LNXSYBUS:00/ACPI0016:00 ├── subsystem -> ../../../../bus/cxl ├── uevent └── uport -> ../../ACPI0017:00 Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/162325695128.2293823.17519927266014762694.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-09 09:43:29 -07:00
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:
cxl/Documentation: List attribute permissions Clarify the access permission of CXL sysfs attributes in the documentation to help development of userspace tooling. Reported-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/165603881198.551046.12893348287451903699.stgit@dwillia2-xfh Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-06-21 17:23:16 -07:00
(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
cxl/acpi: Introduce cxl_decoder objects A cxl_decoder is a child of a cxl_port. It represents a hardware decoder configuration of an upstream port to one or more of its downstream ports. The decoder is either represented in CXL standard HDM decoder registers (see CXL 2.0 section 8.2.5.12 CXL HDM Decoder Capability Structure), or it is a static decode configuration communicated by platform firmware (see the CXL Early Discovery Table: Fixed Memory Window Structure). The firmware described and hardware described decoders differ slightly leading to 2 different sub-types of decoders, cxl_decoder_root and cxl_decoder_switch. At the root level the decode capabilities restrict what can be mapped beneath them. Mid-level switch decoders are configured for either acclerator (type-2) or memory-expander (type-3) operation, but they are otherwise agnostic to the type of memory (volatile vs persistent) being mapped. Here is an example topology from a single-ported host-bridge environment without CFMWS decodes enumerated. /sys/bus/cxl/devices/root0 ├── devtype ├── dport0 -> ../../../LNXSYSTM:00/LNXSYBUS:00/ACPI0016:00 ├── port1 │   ├── decoder1.0 │   │   ├── devtype │   │   ├── locked │   │   ├── size │   │   ├── start │   │   ├── subsystem -> ../../../../../../bus/cxl │   │   ├── target_list │   │   ├── target_type │   │   └── uevent │   ├── devtype │   ├── dport0 -> ../../../../pci0000:34/0000:34:00.0 │   ├── subsystem -> ../../../../../bus/cxl │   ├── uevent │   └── uport -> ../../../../LNXSYSTM:00/LNXSYBUS:00/ACPI0016:00 ├── subsystem -> ../../../../bus/cxl ├── uevent └── uport -> ../../ACPI0017:00 Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/162325695128.2293823.17519927266014762694.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-06-09 09:43:29 -07:00
memory regions are activated in this decode hierarchy.
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