[Skiboot] [PATCH] xive: Disable block tracker

[Benjamin Herrenschmidt]

Due to some HW errata, the block tracking facility (performance optimisation
for large systems) should be disabled on Nimbus chips. Disable it unconditionally
for now.

Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
---
diff --git a/hw/xive.c b/hw/xive.c
index f48d7a41..8245bbf4 100644
--- a/hw/xive.c
+++ b/hw/xive.c
@@ -1762,9 +1762,11 @@ static bool xive_config_init(struct xive *x)
 	val |= VC_SBC_CONF_NO_UPD_PRF;
 	xive_regw(x, VC_SBC_CONFIG, val);
 
-	/* Enable block tracking */
+	/* Disable block tracking on Nubus (we may want to enable
+	 * it on Cumulus later). HW Erratas.
+	 */
 	val = xive_regr(x, PC_TCTXT_TRACK);
-	val |= PC_TCTXT_TRACK_EN;
+	val &= ~PC_TCTXT_TRACK_EN;
 	xive_regw(x, PC_TCTXT_TRACK, val);
 
 	/* Enable relaxed ordering of trigger forwarding */