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| author | Ira Weiny <ira.weiny@intel.com> | 2022-07-19 13:52:49 -0700 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2022-07-19 15:38:05 -0700 |
| commit | c97006046c791f82cb5ba3219ef4a511ec5f3932 (patch) | |
| tree | ce58b9bb8620483ddf69d173a95a911361db7003 /drivers/cxl/cxl.h | |
| parent | 9d6794feeb90903b10c34bddd9c74c992447ce83 (diff) | |
| download | lwn-c97006046c791f82cb5ba3219ef4a511ec5f3932.tar.gz lwn-c97006046c791f82cb5ba3219ef4a511ec5f3932.zip | |
cxl/port: Read CDAT table
The per-device CDAT data provides performance data that is relevant for
mapping which CXL devices can participate in which CXL ranges by QTG
(QoS Throttling Group) (per ECN: CXL 2.0 CEDT CFMWS & QTG_DSM) [1]. The
QTG association specified in the ECN is advisory. Until the
cxl_acpi driver grows support for invoking the QTG _DSM method the CDAT
data is only of interest to userspace that may need it for debug
purposes.
Search the DOE mailboxes available, query CDAT data, cache the data and
make it available via a sysfs binary attribute per endpoint at:
/sys/bus/cxl/devices/endpointX/CDAT
...similar to other ACPI-structured table data in
/sys/firmware/ACPI/tables. The CDAT is relative to 'struct cxl_port'
objects since switches in addition to endpoints can host a CDAT
instance. Switch CDAT support is not implemented.
This does not support table updates at runtime. It will always provide
whatever was there when first cached. It is also the case that table
updates are not expected outside of explicit DPA address map affecting
commands like Set Partition with the immediate flag set. Given that the
driver does not support Set Partition with the immediate flag set there
is no current need for update support.
Link: https://www.computeexpresslink.org/spec-landing [1]
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Co-developed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
[djbw: drop in-kernel parsing infra for now, and other minor fixups]
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20220719205249.566684-7-ira.weiny@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/cxl/cxl.h')
| -rw-r--r-- | drivers/cxl/cxl.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index 570bd9f8141b..21a9d6fcc61e 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -289,6 +289,8 @@ struct cxl_nvdimm { * @component_reg_phys: component register capability base address (optional) * @dead: last ep has been removed, force port re-creation * @depth: How deep this port is relative to the root. depth 0 is the root. + * @cdat: Cached CDAT data + * @cdat_available: Should a CDAT attribute be available in sysfs */ struct cxl_port { struct device dev; @@ -301,6 +303,11 @@ struct cxl_port { resource_size_t component_reg_phys; bool dead; unsigned int depth; + struct cxl_cdat { + void *table; + size_t length; + } cdat; + bool cdat_available; }; /** |