[Skiboot-stable] [PATCH] phb4: Avoid MMIO load freeze escalation on every chip

[Mahesh Salgaonkar]

The commit f397cc30bdf8 ("phb4: Only escalate freezes on MMIO load where
necessary") introduced a change to restrict escalation to the chips that
actually need it. However it missed one case which still causes the
escalation on every chip. This affects EEH recovery to cause full
PHB reset on some chips which is not necessary. This patch fixes that.
Also, add a check for p9 chip in phb4_escalation_required() function.

Cc: skiboot-stable at lists.ozlabs.org
Signed-off-by: Mahesh Salgaonkar <mahesh at linux.ibm.com>
---
 hw/phb4.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/hw/phb4.c b/hw/phb4.c
index e7758d346b..edbcdb2179 100644
--- a/hw/phb4.c
+++ b/hw/phb4.c
@@ -3590,6 +3590,10 @@ static bool phb4_escalation_required(void)
 {
 	uint64_t pvr = mfspr(SPR_PVR);
 
+	/* Only on Power9 */
+	if (proc_gen != proc_gen_p9)
+		return false;
+
 	/*
 	 * Escalation is required on the following chip versions:
 	 * - Cumulus DD1.0
@@ -3850,7 +3854,7 @@ static int64_t phb4_eeh_next_error(struct phb *phb,
 
 	if (*first_frozen_pe != (uint64_t)(-1)) {
 		pesta = phb4_get_pesta(p, *first_frozen_pe);
-		if (phb4_freeze_escalate(pesta)) {
+		if (phb4_escalation_required() && phb4_freeze_escalate(pesta)) {
 			PHBINF(p, "Escalating freeze to fence. PESTA[%lli]=%016llx\n",
 			       *first_frozen_pe, pesta);
 			p->err.err_class = PHB4_ERR_CLASS_FENCED;