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Diffstat (limited to 'Documentation/networking/devlink/devlink-region.rst')
| -rw-r--r-- | Documentation/networking/devlink/devlink-region.rst | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/Documentation/networking/devlink/devlink-region.rst b/Documentation/networking/devlink/devlink-region.rst index 58fe95e9a49d..5d0b68f752c0 100644 --- a/Documentation/networking/devlink/devlink-region.rst +++ b/Documentation/networking/devlink/devlink-region.rst @@ -31,6 +31,15 @@ in its ``devlink_region_ops`` structure. If snapshot id is not set in the ``DEVLINK_CMD_REGION_NEW`` request kernel will allocate one and send the snapshot information to user space. +Regions may optionally allow directly reading from their contents without a +snapshot. Direct read requests are not atomic. In particular a read request +of size 256 bytes or larger will be split into multiple chunks. If atomic +access is required, use a snapshot. A driver wishing to enable this for a +region should implement the ``.read`` callback in the ``devlink_region_ops`` +structure. User space can request a direct read by using the +``DEVLINK_ATTR_REGION_DIRECT`` attribute instead of specifying a snapshot +id. + example usage ------------- @@ -40,12 +49,12 @@ example usage $ devlink region show [ DEV/REGION ] $ devlink region del DEV/REGION snapshot SNAPSHOT_ID $ devlink region dump DEV/REGION [ snapshot SNAPSHOT_ID ] - $ devlink region read DEV/REGION [ snapshot SNAPSHOT_ID ] address ADDRESS length length + $ devlink region read DEV/REGION [ snapshot SNAPSHOT_ID ] address ADDRESS length LENGTH # Show all of the exposed regions with region sizes: $ devlink region show - pci/0000:00:05.0/cr-space: size 1048576 snapshot [1 2] - pci/0000:00:05.0/fw-health: size 64 snapshot [1 2] + pci/0000:00:05.0/cr-space: size 1048576 snapshot [1 2] max 8 + pci/0000:00:05.0/fw-health: size 64 snapshot [1 2] max 8 # Delete a snapshot using: $ devlink region del pci/0000:00:05.0/cr-space snapshot 1 @@ -65,6 +74,10 @@ example usage $ devlink region read pci/0000:00:05.0/fw-health snapshot 1 address 0 length 16 0000000000000000 0014 95dc 0014 9514 0035 1670 0034 db30 + # Read from the region without a snapshot + $ devlink region read pci/0000:00:05.0/fw-health address 16 length 16 + 0000000000000010 0000 0000 ffff ff04 0029 8c00 0028 8cc8 + As regions are likely very device or driver specific, no generic regions are defined. See the driver-specific documentation files for information on the specific regions a driver supports. |