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| author | Ben Widawsky <bwidawsk@kernel.org> | 2022-04-10 15:26:13 -0700 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2022-07-21 17:19:25 -0700 |
| commit | 538831f1beb818c93e5879bf19de37d89ec88ed6 (patch) | |
| tree | 2d55fe7b36b3f4225ad03fbac113f581046ff843 /Documentation/ABI | |
| parent | 391785859e7e6521f622ad8c965c9792767023bc (diff) | |
| download | lwn-538831f1beb818c93e5879bf19de37d89ec88ed6.tar.gz lwn-538831f1beb818c93e5879bf19de37d89ec88ed6.zip | |
cxl/hdm: Add sysfs attributes for interleave ways + granularity
The region provisioning flow involves selecting interleave ways +
granularity settings for a region, and then programming the decoder
topology to meet those constraints, if possible. For example, root
decoders set the minimum interleave ways + granularity for any hosted
regions.
Given decoder programming is not atomic and collisions can occur between
multiple requesting regions userspace will be responsible for conflict
resolution and it needs these attributes to make those decisions.
Signed-off-by: Ben Widawsky <bwidawsk@kernel.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/165784332235.1758207.7185062713652694607.stgit@dwillia2-xfh.jf.intel.com
[djbw: reword changelog, make read-only, add sysfs ABI documentaion]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-cxl | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl index 1ab69aca6152..223b8762d037 100644 --- a/Documentation/ABI/testing/sysfs-bus-cxl +++ b/Documentation/ABI/testing/sysfs-bus-cxl @@ -241,3 +241,30 @@ Description: 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). |