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| author | Dan Williams <dan.j.williams@intel.com> | 2022-06-08 22:56:37 -0700 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2022-07-25 12:18:07 -0700 |
| commit | 176baefb2eb5d7a3ddebe3ff803db1fce44574b5 (patch) | |
| tree | f5a17b35a0051f393fd77a83a7c297e3011587dd /Documentation/ABI | |
| parent | 27b3f8d13830cdbd8deae2b709af182d88237ba5 (diff) | |
| download | linux-176baefb2eb5d7a3ddebe3ff803db1fce44574b5.tar.gz linux-176baefb2eb5d7a3ddebe3ff803db1fce44574b5.tar.bz2 linux-176baefb2eb5d7a3ddebe3ff803db1fce44574b5.zip | |
cxl/hdm: Commit decoder state to hardware
After all the soft validation of the region has completed, convey the
region configuration to hardware while being careful to commit decoders
in specification mandated order. In addition to programming the endpoint
decoder base-address, interleave ways and granularity, the switch
decoder target lists are also established.
While the kernel can enforce spec-mandated commit order, it can not
enforce spec-mandated reset order. For example, the kernel can't stop
someone from removing an endpoint device that is occupying decoderN in a
switch decoder where decoderN+1 is also committed. To reset decoderN,
decoderN+1 must be torn down first. That "tear down the world"
implementation is saved for a follow-on patch.
Callback operations are provided for the 'commit' and 'reset'
operations. While those callbacks may prove useful for CXL accelerators
(Type-2 devices with memory) the primary motivation is to enable a
simple way for cxl_test to intercept those operations.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/165784338418.1758207.14659830845389904356.stgit@dwillia2-xfh.jf.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-cxl | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl index 4ecf6cf40fd3..8494ef27e8d2 100644 --- a/Documentation/ABI/testing/sysfs-bus-cxl +++ b/Documentation/ABI/testing/sysfs-bus-cxl @@ -372,3 +372,19 @@ Description: 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. |