Add function to find if host is transitioning to PHYP

Utilizing the xyz.openbmc_project.State.Host interface to ascertain the
host's operational status becomes less accurate when transitioning from
hostboot to PHYP. During the period when PHYP is initializing and not
yet fully operational, the host state is erroneously presumed to be in
hostboot. In situations where PHYP encounters initial boot difficulties
and activates a watchdog timer, this watchdog misinterprets the issue as
a problem with hostboot.

To address this, there exists a core scratch register that undergoes an
update by hostboot just before transferring control to PHYP. We have
devised a method that leverages this register to determine whether the
transition to PHYP has already occurred.

By implementing this functionality, we can accurately determine whether
control has transitioned to PHYP, allowing for more precise reporting of
the host's state.

Signed-off-by: Deepa Karthikeyan <[email protected]>

libphal/libphal.H

@@ -271,6 +271,13 @@ void putCFAM(struct pdbg_target *proc, const uint32_t addr, const uint32_t val);
  */
 bool isSbeVitalAttnActive(struct pdbg_target *proc);
 
+/**
+ * @brief Check if Hostboot has completed and the control transistioned to PHYP
+ *
+ * @return true when we have moved to PHYP
+ */
+bool hasControlTransitionedToPHYP();
+
 } // namespace pdbg
 
 namespace dump

libphal/phal_pdbg.C

@@ -280,4 +280,31 @@ bool isSbeVitalAttnActive(struct pdbg_target *proc)
 	return validAttn;
 }
 
+bool hasControlTransitionedToPHYP()
+{
+  // If unable to read the register, by default consider the control is in hostboot
+  bool transitionedToPHYP = false;
+  //Read the scratch register to find if the host is transitioned to phyp
+  pdbg_target* pibTarget = pdbg_target_from_path(nullptr, "/proc0/pib");
+
+  uint64_t l_coreScratchRegData = 0xFFFFFFFFFFFFFFFFull;
+  // HB changes the below core scratch reg as one of the last instructions that is run,
+  // so if that is zero then we're in phyp
+  uint64_t l_coreScratchRegAddr = 0x4602F489;
+
+  // Is there any error in reading the scom address, assign default value to data
+  if (0 != pib_read(pibTarget, l_coreScratchRegAddr, &l_coreScratchRegData))
+  {
+      log(level::ERROR, "scom read error: 0x%X", l_coreScratchRegAddr );
+      l_coreScratchRegData = 0xFFFFFFFFFFFFFFFFull;
+  }
+
+  // If the register reads zero, return control moved to phyp.
+  if(l_coreScratchRegData == 0)
+  {
+    transitionedToPHYP = true;
+  }
+  return transitionedToPHYP;
+}
+
 } // namespace openpower::phal::pdbg