Add Documenation for opal_slw_set_reg

Signed-off-by: Akshay Adiga <akshay.adiga@linux.vnet.ibm.com>
Reviewed-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

1 files changed, 46 insertions, 0 deletions

diff --git a/doc/opal-api/opal-slw-set-reg-100.rst b/doc/opal-api/opal-slw-set-reg-100.rst
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+OPAL_SLW_SET_REG
+==============================
+::
+
+    int64_t opal_slw_set_reg(uint64_t cpu_pir, uint64_t sprn, uint64_t val)
+
+
+OPAL_SLW_SET_REG is used to inform low-level firmware to restore a
+given value of SPR when there is a state loss.  The actual set of SPR
+that is supported is platform dependent.
+
+
+In Power 8, it uses p8_pore_gen_cpufreq_fixed(), api provided by pore engine,
+to inform the spr with their corresponding values with which they
+must be restored.
+
+
+In Power 9, it uses p9_stop_save_cpureg(), api provided by self restore code,
+to inform the spr with their corresponding values with which they
+must be restored.
+
+
+Parameters
+----------
+
+``uint64_t cpu_pir``
+This parameter specifies the pir of the cpu for which the call is being made.
+
+``uint64_t sprn``
+This parameter specifies the spr number as mentioned in p9_stop_api.H for
+Power9 and p8_pore_table_gen_api.H for Power8.
+
+``uint64_t val``
+This parameter specifices value with which the spr should be restored.
+
+Returns
+-------
+
+``OPAL_INTERNAL_ERROR``
+On failure. The actual error code from the platform specific code is logged in the OPAL logs
+
+``OPAL_UNSUPPORTED``
+In power8 only, if spr restore is not supported by pore engine.
+
+``OPAL_SUCCESS``
+On success