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author | Linus Torvalds | 2019-07-09 21:34:26 +0200 |
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committer | Linus Torvalds | 2019-07-09 21:34:26 +0200 |
commit | e9a83bd2322035ed9d7dcf35753d3f984d76c6a5 (patch) | |
tree | 66dc466ff9aec0f9bb7f39cba50a47eab6585559 /Documentation/watchdog/mlx-wdt.rst | |
parent | Merge tag 'printk-for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/p... (diff) | |
parent | docs: automarkup.py: ignore exceptions when seeking for xrefs (diff) | |
download | kernel-qcow2-linux-e9a83bd2322035ed9d7dcf35753d3f984d76c6a5.tar.gz kernel-qcow2-linux-e9a83bd2322035ed9d7dcf35753d3f984d76c6a5.tar.xz kernel-qcow2-linux-e9a83bd2322035ed9d7dcf35753d3f984d76c6a5.zip |
Merge tag 'docs-5.3' of git://git.lwn.net/linux
Pull Documentation updates from Jonathan Corbet:
"It's been a relatively busy cycle for docs:
- A fair pile of RST conversions, many from Mauro. These create more
than the usual number of simple but annoying merge conflicts with
other trees, unfortunately. He has a lot more of these waiting on
the wings that, I think, will go to you directly later on.
- A new document on how to use merges and rebases in kernel repos,
and one on Spectre vulnerabilities.
- Various improvements to the build system, including automatic
markup of function() references because some people, for reasons I
will never understand, were of the opinion that
:c:func:``function()`` is unattractive and not fun to type.
- We now recommend using sphinx 1.7, but still support back to 1.4.
- Lots of smaller improvements, warning fixes, typo fixes, etc"
* tag 'docs-5.3' of git://git.lwn.net/linux: (129 commits)
docs: automarkup.py: ignore exceptions when seeking for xrefs
docs: Move binderfs to admin-guide
Disable Sphinx SmartyPants in HTML output
doc: RCU callback locks need only _bh, not necessarily _irq
docs: format kernel-parameters -- as code
Doc : doc-guide : Fix a typo
platform: x86: get rid of a non-existent document
Add the RCU docs to the core-api manual
Documentation: RCU: Add TOC tree hooks
Documentation: RCU: Rename txt files to rst
Documentation: RCU: Convert RCU UP systems to reST
Documentation: RCU: Convert RCU linked list to reST
Documentation: RCU: Convert RCU basic concepts to reST
docs: filesystems: Remove uneeded .rst extension on toctables
scripts/sphinx-pre-install: fix out-of-tree build
docs: zh_CN: submitting-drivers.rst: Remove a duplicated Documentation/
Documentation: PGP: update for newer HW devices
Documentation: Add section about CPU vulnerabilities for Spectre
Documentation: platform: Delete x86-laptop-drivers.txt
docs: Note that :c:func: should no longer be used
...
Diffstat (limited to 'Documentation/watchdog/mlx-wdt.rst')
-rw-r--r-- | Documentation/watchdog/mlx-wdt.rst | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/Documentation/watchdog/mlx-wdt.rst b/Documentation/watchdog/mlx-wdt.rst new file mode 100644 index 000000000000..bf5bafac47f0 --- /dev/null +++ b/Documentation/watchdog/mlx-wdt.rst @@ -0,0 +1,56 @@ +========================= +Mellanox watchdog drivers +========================= + +for x86 based system switches +============================= + +This driver provides watchdog functionality for various Mellanox +Ethernet and Infiniband switch systems. + +Mellanox watchdog device is implemented in a programmable logic device. + +There are 2 types of HW watchdog implementations. + +Type 1: + Actual HW timeout can be defined as a power of 2 msec. + e.g. timeout 20 sec will be rounded up to 32768 msec. + The maximum timeout period is 32 sec (32768 msec.), + Get time-left isn't supported + +Type 2: + Actual HW timeout is defined in sec. and it's the same as + a user-defined timeout. + Maximum timeout is 255 sec. + Get time-left is supported. + +Type 1 HW watchdog implementation exist in old systems and +all new systems have type 2 HW watchdog. +Two types of HW implementation have also different register map. + +Mellanox system can have 2 watchdogs: main and auxiliary. +Main and auxiliary watchdog devices can be enabled together +on the same system. +There are several actions that can be defined in the watchdog: +system reset, start fans on full speed and increase register counter. +The last 2 actions are performed without a system reset. +Actions without reset are provided for auxiliary watchdog device, +which is optional. +Watchdog can be started during a probe, in this case it will be +pinged by watchdog core before watchdog device will be opened by +user space application. +Watchdog can be initialised in nowayout way, i.e. oncse started +it can't be stopped. + +This mlx-wdt driver supports both HW watchdog implementations. + +Watchdog driver is probed from the common mlx_platform driver. +Mlx_platform driver provides an appropriate set of registers for +Mellanox watchdog device, identity name (mlx-wdt-main or mlx-wdt-aux), +initial timeout, performed action in expiration and configuration flags. +watchdog configuration flags: nowayout and start_at_boot, hw watchdog +version - type1 or type2. +The driver checks during initialization if the previous system reset +was done by the watchdog. If yes, it makes a notification about this event. + +Access to HW registers is performed through a generic regmap interface. |