[POWERPC] EDAC ECC software scrubber

Implements the per arch atomic_scrub() that EDAC uses for software
ECC scrubbing.  It reads memory and then writes back the original
value, allowing the hardware to detect and correct memory errors.

Signed-off-by: Dave Jiang <djiang@mvista.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 40 insertions, 0 deletions

diff --git a/include/asm-powerpc/edac.h b/include/asm-powerpc/edac.h
new file mode 100644
index 000000000000..6ead88bbfbb8
--- /dev/null
+++ b/include/asm-powerpc/edac.h
@@ -0,0 +1,40 @@
+/*
+ * PPC EDAC common defs
+ *
+ * Author: Dave Jiang <djiang@mvista.com>
+ *
+ * 2007 (c) MontaVista Software, Inc. This file is licensed under
+ * the terms of the GNU General Public License version 2. This program
+ * is licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ */
+#ifndef ASM_EDAC_H
+#define ASM_EDAC_H
+/*
+ * ECC atomic, DMA, SMP and interrupt safe scrub function.
+ * Implements the per arch atomic_scrub() that EDAC use for software
+ * ECC scrubbing.  It reads memory and then writes back the original
+ * value, allowing the hardware to detect and correct memory errors.
+ */
+static __inline__ void atomic_scrub(void *va, u32 size)
+{
+        unsigned int *virt_addr = va;
+        unsigned int temp;
+        unsigned int i;
+
+        for (i = 0; i < size / sizeof(*virt_addr); i++, virt_addr++) {
+                /* Very carefully read and write to memory atomically
+                 * so we are interrupt, DMA and SMP safe.
+                 */
+                __asm__ __volatile__ ("\n\
+                                1:      lwarx   %0,0,%1\n\
+                                        stwcx.  %0,0,%1\n\
+                                        bne-    1b\n\
+                                        isync"
+                                        : "=&r"(temp)
+                                        : "r"(virt_addr)
+                                        : "cr0", "memory");
+        }
+}
+
+#endif