[Skiboot] [PATCH v8 3/3] Self save API integration

[Vaidyanathan Srinivasan]

* Pratik Rajesh Sampat <psampat at linux.ibm.com> [2020-04-23 16:24:38]:

> The commit makes the self save API available outside the firmware by defining
> an OPAL wrapper.
> This wrapper has a similar interface to that of self restore and expects the
> cpu pir, SPR number, minus the value of that SPR to be passed in its
> paramters and returns OPAL_SUCCESS on success. It adds a device-tree
> node signifying support for self-save after verifying the stop API
> version compatibility.
> 
> The commit also documents both the self-save and the self-restore API
> calls along with their working and usage.
> 
> Signed-off-by: Pratik Rajesh Sampat <psampat at linux.ibm.com>

Reviewed-by: Vaidyanathan Srinivasan <svaidy at linux.ibm.com>

> ---
>  doc/opal-api/opal-slw-self-save-reg-181.rst |  51 ++++++++++
>  doc/opal-api/opal-slw-set-reg-100.rst       |   5 +
>  doc/power-management.rst                    |  48 +++++++++
>  hw/slw.c                                    | 106 ++++++++++++++++++++
>  include/opal-api.h                          |   3 +-
>  include/p9_stop_api.H                       |  18 ++++
>  include/skiboot.h                           |   3 +
>  7 files changed, 233 insertions(+), 1 deletion(-)
>  create mode 100644 doc/opal-api/opal-slw-self-save-reg-181.rst

This patch enables OPAL interface to call stop-api and set self-save.
Basically completes the infrastructure required to use the new
self-save function provided by the microcode.

--Vaidy