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+.. SPDX-License-Identifier: GPL-2.0
+
+======================
+Multi-Level Interleave
+======================
+This cxl-cli configuration dump shows the following host configuration:
+
+* A single socket system with one CXL root
+* CXL Root has Four (4) CXL Host Bridges
+* Two CXL Host Bridges have a two CXL Memory Expanders Attached each.
+* The CXL root is configured to interleave across the two host bridges.
+* Each host bridge with expanders interleaves across two endpoints.
+
+This output is generated by :code:`cxl list -v` and describes the relationships
+between objects exposed in :code:`/sys/bus/cxl/devices/`.
+
+::
+
+ [
+ {
+ "bus":"root0",
+ "provider":"ACPI.CXL",
+ "nr_dports":4,
+ "dports":[
+ {
+ "dport":"pci0000:00",
+ "alias":"ACPI0016:01",
+ "id":0
+ },
+ {
+ "dport":"pci0000:a8",
+ "alias":"ACPI0016:02",
+ "id":4
+ },
+ {
+ "dport":"pci0000:2a",
+ "alias":"ACPI0016:03",
+ "id":1
+ },
+ {
+ "dport":"pci0000:d2",
+ "alias":"ACPI0016:00",
+ "id":5
+ }
+ ],
+
+This chunk shows the CXL "bus" (root0) has 4 downstream ports attached to CXL
+Host Bridges. The `Root` can be considered the singular upstream port attached
+to the platform's memory controller - which routes memory requests to it.
+
+The `ports:root0` section lays out how each of these downstream ports are
+configured. If a port is not configured (id's 0 and 1), they are omitted.
+
+::
+
+ "ports:root0":[
+ {
+ "port":"port1",
+ "host":"pci0000:d2",
+ "depth":1,
+ "nr_dports":3,
+ "dports":[
+ {
+ "dport":"0000:d2:01.1",
+ "alias":"device:02",
+ "id":0
+ },
+ {
+ "dport":"0000:d2:01.3",
+ "alias":"device:05",
+ "id":2
+ },
+ {
+ "dport":"0000:d2:07.1",
+ "alias":"device:0d",
+ "id":113
+ }
+ ],
+
+This chunk shows the available downstream ports associated with the CXL Host
+Bridge :code:`port1`. In this case, :code:`port1` has 3 available downstream
+ports: :code:`dport0`, :code:`dport2`, and :code:`dport113`.
+
+::
+
+ "endpoints:port1":[
+ {
+ "endpoint":"endpoint5",
+ "host":"mem0",
+ "parent_dport":"0000:d2:01.1",
+ "depth":2,
+ "memdev":{
+ "memdev":"mem0",
+ "ram_size":137438953472,
+ "serial":0,
+ "numa_node":0,
+ "host":"0000:d3:00.0"
+ },
+ "decoders:endpoint5":[
+ {
+ "decoder":"decoder5.0",
+ "resource":825975898112,
+ "size":549755813888,
+ "interleave_ways":4,
+ "interleave_granularity":256,
+ "region":"region0",
+ "dpa_resource":0,
+ "dpa_size":137438953472,
+ "mode":"ram"
+ }
+ ]
+ },
+ {
+ "endpoint":"endpoint6",
+ "host":"mem1",
+ "parent_dport":"0000:d2:01.3",
+ "depth":2,
+ "memdev":{
+ "memdev":"mem1",
+ "ram_size":137438953472,
+ "serial":0,
+ "numa_node":0,
+ "host":"0000:d3:00.0"
+ },
+ "decoders:endpoint6":[
+ {
+ "decoder":"decoder6.0",
+ "resource":825975898112,
+ "size":549755813888,
+ "interleave_ways":4,
+ "interleave_granularity":256,
+ "region":"region0",
+ "dpa_resource":0,
+ "dpa_size":137438953472,
+ "mode":"ram"
+ }
+ ]
+ }
+ ],
+
+This chunk shows the endpoints attached to the host bridge :code:`port1`.
+
+:code:`endpoint5` contains a single configured decoder :code:`decoder5.0`
+which has the same interleave configuration as :code:`region0` (shown later).
+
+:code:`endpoint6` contains a single configured decoder :code:`decoder5.0`
+which has the same interleave configuration as :code:`region0` (shown later).
+
+Next we have the decoders belonging to the host bridge:
+
+::
+
+ "decoders:port1":[
+ {
+ "decoder":"decoder1.0",
+ "resource":825975898112,
+ "size":549755813888,
+ "interleave_ways":2,
+ "interleave_granularity":512,
+ "region":"region0",
+ "nr_targets":2,
+ "targets":[
+ {
+ "target":"0000:d2:01.1",
+ "alias":"device:02",
+ "position":0,
+ "id":0
+ },
+ {
+ "target":"0000:d2:01.3",
+ "alias":"device:05",
+ "position":2,
+ "id":0
+ }
+ ]
+ }
+ ]
+ },
+
+Host Bridge :code:`port1` has a single decoder (:code:`decoder1.0`), whose
+targets are :code:`dport0` and :code:`dport2` - which are attached to
+:code:`endpoint5` and :code:`endpoint6` respectively.
+
+The following chunk shows a similar configuration for Host Bridge :code:`port3`,
+the second host bridge with a memory device attached.
+
+::
+
+ {
+ "port":"port3",
+ "host":"pci0000:a8",
+ "depth":1,
+ "nr_dports":1,
+ "dports":[
+ {
+ "dport":"0000:a8:01.1",
+ "alias":"device:c3",
+ "id":0
+ },
+ {
+ "dport":"0000:a8:01.3",
+ "alias":"device:c5",
+ "id":0
+ }
+ ],
+ "endpoints:port3":[
+ {
+ "endpoint":"endpoint7",
+ "host":"mem2",
+ "parent_dport":"0000:a8:01.1",
+ "depth":2,
+ "memdev":{
+ "memdev":"mem2",
+ "ram_size":137438953472,
+ "serial":0,
+ "numa_node":0,
+ "host":"0000:a9:00.0"
+ },
+ "decoders:endpoint7":[
+ {
+ "decoder":"decoder7.0",
+ "resource":825975898112,
+ "size":549755813888,
+ "interleave_ways":4,
+ "interleave_granularity":256,
+ "region":"region0",
+ "dpa_resource":0,
+ "dpa_size":137438953472,
+ "mode":"ram"
+ }
+ ]
+ },
+ {
+ "endpoint":"endpoint8",
+ "host":"mem3",
+ "parent_dport":"0000:a8:01.3",
+ "depth":2,
+ "memdev":{
+ "memdev":"mem3",
+ "ram_size":137438953472,
+ "serial":0,
+ "numa_node":0,
+ "host":"0000:a9:00.0"
+ },
+ "decoders:endpoint8":[
+ {
+ "decoder":"decoder8.0",
+ "resource":825975898112,
+ "size":549755813888,
+ "interleave_ways":4,
+ "interleave_granularity":256,
+ "region":"region0",
+ "dpa_resource":0,
+ "dpa_size":137438953472,
+ "mode":"ram"
+ }
+ ]
+ }
+ ],
+ "decoders:port3":[
+ {
+ "decoder":"decoder3.0",
+ "resource":825975898112,
+ "size":549755813888,
+ "interleave_ways":2,
+ "interleave_granularity":512,
+ "region":"region0",
+ "nr_targets":1,
+ "targets":[
+ {
+ "target":"0000:a8:01.1",
+ "alias":"device:c3",
+ "position":1,
+ "id":0
+ },
+ {
+ "target":"0000:a8:01.3",
+ "alias":"device:c5",
+ "position":3,
+ "id":0
+ }
+ ]
+ }
+ ]
+ },
+
+
+The next chunk shows the two CXL host bridges without attached endpoints.
+
+::
+
+ {
+ "port":"port2",
+ "host":"pci0000:00",
+ "depth":1,
+ "nr_dports":2,
+ "dports":[
+ {
+ "dport":"0000:00:01.3",
+ "alias":"device:55",
+ "id":2
+ },
+ {
+ "dport":"0000:00:07.1",
+ "alias":"device:5d",
+ "id":113
+ }
+ ]
+ },
+ {
+ "port":"port4",
+ "host":"pci0000:2a",
+ "depth":1,
+ "nr_dports":1,
+ "dports":[
+ {
+ "dport":"0000:2a:01.1",
+ "alias":"device:d0",
+ "id":0
+ }
+ ]
+ }
+ ],
+
+Next we have the `Root Decoders` belonging to :code:`root0`. This root decoder
+applies the interleave across the downstream ports :code:`port1` and
+:code:`port3` - with a granularity of 256 bytes.
+
+This information is generated by the CXL driver reading the ACPI CEDT CMFWS.
+
+::
+
+ "decoders:root0":[
+ {
+ "decoder":"decoder0.0",
+ "resource":825975898112,
+ "size":549755813888,
+ "interleave_ways":2,
+ "interleave_granularity":256,
+ "max_available_extent":0,
+ "volatile_capable":true,
+ "nr_targets":2,
+ "targets":[
+ {
+ "target":"pci0000:a8",
+ "alias":"ACPI0016:02",
+ "position":1,
+ "id":4
+ },
+ {
+ "target":"pci0000:d2",
+ "alias":"ACPI0016:00",
+ "position":0,
+ "id":5
+ }
+ ],
+
+Finally we have the `Memory Region` associated with the `Root Decoder`
+:code:`decoder0.0`. This region describes the overall interleave configuration
+of the interleave set. So we see there are a total of :code:`4` interleave
+targets across 4 endpoint decoders.
+
+::
+
+ "regions:decoder0.0":[
+ {
+ "region":"region0",
+ "resource":825975898112,
+ "size":549755813888,
+ "type":"ram",
+ "interleave_ways":4,
+ "interleave_granularity":256,
+ "decode_state":"commit",
+ "mappings":[
+ {
+ "position":3,
+ "memdev":"mem3",
+ "decoder":"decoder8.0"
+ },
+ {
+ "position":2,
+ "memdev":"mem1",
+ "decoder":"decoder6.0"
+ }
+ {
+ "position":1,
+ "memdev":"mem2",
+ "decoder":"decoder7.0"
+ },
+ {
+ "position":0,
+ "memdev":"mem0",
+ "decoder":"decoder5.0"
+ }
+ ]
+ }
+ ]
+ }
+ ]
+ }
+ ]
generated by cgit (git 2.34.1) at 2025-06-06 14:58:41 +0000