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| author | Stewart Smith <stewart@linux.ibm.com> | 2018-04-03 14:57:56 +1000 |
|---|---|---|
| committer | Stewart Smith <stewart@linux.vnet.ibm.com> | 2018-04-03 03:30:46 -0500 |
| commit | 6bfe04890f094bf38824fc3e445a4fee7aa6bece (patch) | |
| tree | c98919b69eff6915439177ea52acbeac2c093230 /doc/device-tree | |
| parent | 1d7067e7a3f5fa7823236616caaf94e4809cc5fb (diff) | |
| download | skiboot-6bfe04890f094bf38824fc3e445a4fee7aa6bece.zip skiboot-6bfe04890f094bf38824fc3e445a4fee7aa6bece.tar.gz skiboot-6bfe04890f094bf38824fc3e445a4fee7aa6bece.tar.bz2 | |
doc: Document ibm,heartbeat-ms
and by 'document', I mean 'gather a few extra minor bits of breadcrumbs
of clues as to what, when and why this thing exists'.
Signed-off-by: Stewart Smith <stewart@linux.ibm.com>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Diffstat (limited to 'doc/device-tree')
| -rw-r--r-- | doc/device-tree/ibm,opal.rst | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/doc/device-tree/ibm,opal.rst b/doc/device-tree/ibm,opal.rst index 932f41d..2fa446d 100644 --- a/doc/device-tree/ibm,opal.rst +++ b/doc/device-tree/ibm,opal.rst @@ -50,3 +50,24 @@ Top level ibm,opal node opal-runtime-size = <0x0 0x9a00000>; phandle = <0x10000003>; }; + +.. ibm-heartbeat-ms: + +ibm,heartbeat-ms +^^^^^^^^^^^^^^^^ + +.. code-block:: dts + + ibm,opal { + ibm,heartbeat-ms = <0x7d0>; + } + + +Any OS targetting POWER9 processors *must* respect `ibm,heartbeat-ms`. + +Linux kernels prior to v4.1-rc1 would ignore `ibm,heartbeat-ms`. These only +supported POWER8 systems. + +On the earliest POWER8 OPAL systems, there was `ibm,heartbeat-freq` instead. +However, no OS at the time ever looked at that value, so it can be ignored +by any new operating systems. |