Module Name: src
Committed By: nakayama
Date: Mon Dec 7 11:24:30 UTC 2009
Modified Files:
src/sys/arch/sparc64/dev: iommu.c
Log Message:
Add comment about an uncorrectable DMA error sometimes observed on
tlp(4) on Netra X1, and its workaround.
Also add membar_storestore, from OpenBSD.
To generate a diff of this commit:
cvs rdiff -u -r1.93 -r1.94 src/sys/arch/sparc64/dev/iommu.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/sparc64/dev/iommu.c
diff -u src/sys/arch/sparc64/dev/iommu.c:1.93 src/sys/arch/sparc64/dev/iommu.c:1.94
--- src/sys/arch/sparc64/dev/iommu.c:1.93 Mon Dec 7 11:18:38 2009
+++ src/sys/arch/sparc64/dev/iommu.c Mon Dec 7 11:24:30 2009
@@ -1,4 +1,4 @@
-/* $NetBSD: iommu.c,v 1.93 2009/12/07 11:18:38 nakayama Exp $ */
+/* $NetBSD: iommu.c,v 1.94 2009/12/07 11:24:30 nakayama Exp $ */
/*
* Copyright (c) 1999, 2000 Matthew R. Green
@@ -59,7 +59,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: iommu.c,v 1.93 2009/12/07 11:18:38 nakayama Exp $");
+__KERNEL_RCSID(0, "$NetBSD: iommu.c,v 1.94 2009/12/07 11:24:30 nakayama Exp $");
#include "opt_ddb.h"
@@ -349,8 +349,17 @@
else
len -= PAGE_SIZE;
- /* XXX Zero-ing the entry would not require RMW */
+ /*
+ * XXX Zero-ing the entry would not require RMW
+ *
+ * Disabling valid bit while a page is used by a device
+ * causes an uncorrectable DMA error.
+ * Workaround to avoid an uncorrectable DMA error is
+ * eliminating the next line, but the page is mapped
+ * until the next iommu_enter call.
+ */
is->is_tsb[IOTSBSLOT(va,is->is_tsbsize)] &= ~IOTTE_V;
+ membar_storestore();
bus_space_write_8(is->is_bustag, is->is_iommu,
IOMMUREG(iommu_flush), va);
va += PAGE_SIZE;
