[Skiboot] [PATCH] core/hmi.c: Don't attempt to decode malfunction alerts for unsupported chips

[Alistair Popple]

Currently decode_malfunction() attempts to decode HMI events by looking at xscom
registers which are specific to P8. Obviously this doesn't work on P9 as many of
these addresses and HW interfaces have changed which results in further HMI
events due to invalid SCOM addresses accesses. Until decode_malfunction()
understands how to decode P9 HMI events it is better to just bail with an
unknown HMI event which will ultimately cause the OS to request a reboot.

Signed-off-by: Alistair Popple <alistair at popple.id.au>
---
 core/hmi.c | 30 +++++++++++++++++++-----------
 1 file changed, 19 insertions(+), 11 deletions(-)

diff --git a/core/hmi.c b/core/hmi.c
index 84f2c2d..4fb7d75 100644
--- a/core/hmi.c
+++ b/core/hmi.c
@@ -528,22 +528,30 @@ static void decode_malfunction(struct OpalHMIEvent *hmi_evt)
 	int i;
 	uint64_t malf_alert;
 	bool event_generated = false;
+	struct proc_chip *chip = next_chip(NULL);
 
-	xscom_read(this_cpu()->chip_id, 0x2020011, &malf_alert);
+	/* The below code does not appear to support anything other than P8 so
+	 * we should avoid running it on other chips to avoid generating further
+	 * events due to reading bad xscom addresses. */
+	if (chip->type == PROC_CHIP_P8_MURANO || \
+	    chip->type == PROC_CHIP_P8_VENICE || \
+	    chip->type == PROC_CHIP_P8_NAPLES) {
+		xscom_read(this_cpu()->chip_id, 0x2020011, &malf_alert);
 
-	if (!malf_alert)
-		return;
+		if (!malf_alert)
+			return;
 
-	for (i = 0; i < 64; i++) {
-		if (malf_alert & PPC_BIT(i)) {
-			xscom_write(this_cpu()->chip_id, 0x02020011, ~PPC_BIT(i));
-			find_capp_checkstop_reason(i, hmi_evt, &event_generated);
-			find_nx_checkstop_reason(i, hmi_evt, &event_generated);
-			find_npu_checkstop_reason(i, hmi_evt, &event_generated);
+		for (i = 0; i < 64; i++) {
+			if (malf_alert & PPC_BIT(i)) {
+				xscom_write(this_cpu()->chip_id, 0x02020011, ~PPC_BIT(i));
+				find_capp_checkstop_reason(i, hmi_evt, &event_generated);
+				find_nx_checkstop_reason(i, hmi_evt, &event_generated);
+				find_npu_checkstop_reason(i, hmi_evt, &event_generated);
+			}
 		}
-	}
 
-	find_core_checkstop_reason(hmi_evt, &event_generated);
+		find_core_checkstop_reason(hmi_evt, &event_generated);
+	}
 
 	/*
 	 * If we fail to find checkstop reason, send an unknown HMI event.
-- 
2.1.4