| Message ID | 20180403045756.31804-1-stewart@linux.ibm.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | doc: Document ibm,heartbeat-ms | expand |
On Tue, Apr 3, 2018 at 2:57 PM, Stewart Smith <stewart@linux.ibm.com> wrote: > 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> > --- > doc/device-tree/ibm,opal.rst | 21 +++++++++++++++++++++ > 1 file changed, 21 insertions(+) > > diff --git a/doc/device-tree/ibm,opal.rst b/doc/device-tree/ibm,opal.rst > index 932f41d05cde..2fa446ddef04 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. Doesn't this set the interval between calls to OPAL_POLL_EVENTS? I think as a side effect we also run the pollers inside of skiboot so you need it to make centaur I2C work too. We should probably document that :) > -- > 2.14.3 > > _______________________________________________ > Skiboot mailing list > Skiboot@lists.ozlabs.org > https://lists.ozlabs.org/listinfo/skiboot
Oliver <oohall@gmail.com> writes: > On Tue, Apr 3, 2018 at 2:57 PM, Stewart Smith <stewart@linux.ibm.com> wrote: >> 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> >> --- >> doc/device-tree/ibm,opal.rst | 21 +++++++++++++++++++++ >> 1 file changed, 21 insertions(+) >> >> diff --git a/doc/device-tree/ibm,opal.rst b/doc/device-tree/ibm,opal.rst >> index 932f41d05cde..2fa446ddef04 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. > > Doesn't this set the interval between calls to OPAL_POLL_EVENTS? I > think as a side effect > we also run the pollers inside of skiboot so you need it to make > centaur I2C work too. > We should probably document that :) I'm pretty sure it's documented in hw/i2c.c[1] [1] Yes, I'm aware the source code is in hw/p8-i2c.c - I'm attempting to be funny. Not ha-ha funny though.
Stewart Smith <stewart@linux.ibm.com> writes: > 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> > --- > doc/device-tree/ibm,opal.rst | 21 +++++++++++++++++++++ > 1 file changed, 21 insertions(+) It's an improvement over the literal nothing we currently have. Merged to master as of 6bfe04890f094bf38824fc3e445a4fee7aa6bece
diff --git a/doc/device-tree/ibm,opal.rst b/doc/device-tree/ibm,opal.rst index 932f41d05cde..2fa446ddef04 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.
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> --- doc/device-tree/ibm,opal.rst | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)