forked from Minki/linux
b9a17abfde
Implement support for the DEVLINK_CMD_REGION_NEW command for creating snapshots. This new command parallels the existing DEVLINK_CMD_REGION_DEL. In order for DEVLINK_CMD_REGION_NEW to work for a region, the new ".snapshot" operation must be implemented in the region's ops structure. The desired snapshot id must be provided. This helps avoid confusion on the purpose of DEVLINK_CMD_REGION_NEW, and keeps the API simpler. The requested id will be inserted into the xarray tracking the number of snapshots using each id. If this id is already used by another snapshot on any region, an error will be returned. Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Reviewed-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
66 lines
2.4 KiB
ReStructuredText
66 lines
2.4 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
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==============
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Devlink Region
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==============
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``devlink`` regions enable access to driver defined address regions using
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devlink.
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Each device can create and register its own supported address regions. The
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region can then be accessed via the devlink region interface.
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Region snapshots are collected by the driver, and can be accessed via read
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or dump commands. This allows future analysis on the created snapshots.
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Regions may optionally support triggering snapshots on demand.
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The major benefit to creating a region is to provide access to internal
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address regions that are otherwise inaccessible to the user.
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Regions may also be used to provide an additional way to debug complex error
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states, but see also :doc:`devlink-health`
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Regions may optionally support capturing a snapshot on demand via the
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``DEVLINK_CMD_REGION_NEW`` netlink message. A driver wishing to allow
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requested snapshots must implement the ``.snapshot`` callback for the region
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in its ``devlink_region_ops`` structure.
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example usage
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-------------
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.. code:: shell
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$ devlink region help
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$ devlink region show [ DEV/REGION ]
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$ devlink region del DEV/REGION snapshot SNAPSHOT_ID
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$ devlink region dump DEV/REGION [ snapshot SNAPSHOT_ID ]
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$ devlink region read DEV/REGION [ snapshot SNAPSHOT_ID ]
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address ADDRESS length length
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# Show all of the exposed regions with region sizes:
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$ devlink region show
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pci/0000:00:05.0/cr-space: size 1048576 snapshot [1 2]
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pci/0000:00:05.0/fw-health: size 64 snapshot [1 2]
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# Delete a snapshot using:
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$ devlink region del pci/0000:00:05.0/cr-space snapshot 1
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# Request an immediate snapshot, if supported by the region
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$ devlink region new pci/0000:00:05.0/cr-space snapshot 5
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# Dump a snapshot:
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$ devlink region dump pci/0000:00:05.0/fw-health snapshot 1
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0000000000000000 0014 95dc 0014 9514 0035 1670 0034 db30
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0000000000000010 0000 0000 ffff ff04 0029 8c00 0028 8cc8
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0000000000000020 0016 0bb8 0016 1720 0000 0000 c00f 3ffc
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0000000000000030 bada cce5 bada cce5 bada cce5 bada cce5
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# Read a specific part of a snapshot:
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$ devlink region read pci/0000:00:05.0/fw-health snapshot 1 address 0
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length 16
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0000000000000000 0014 95dc 0014 9514 0035 1670 0034 db30
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As regions are likely very device or driver specific, no generic regions are
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defined. See the driver-specific documentation files for information on the
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specific regions a driver supports.
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