[PATCH] Retain the write-only OD from being clobbered

["Jordan Crouse" <jordan.crouse@amd.com>]

First of several patches forwarded to me by Sergei Shtylyov.  Ralf,
these should be good to go for the tree.

Retain the write-only OD bit from being clobbered by coherency_setup()

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Acked-by: Jordan Crouse <jordan.crouse@amd.com>
---

 arch/mips/mm/c-r4k.c |   14 ++++++++++++++
 1 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index 38223b4..044c468 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -29,6 +29,10 @@
 #include <asm/war.h>
 #include <asm/cacheflush.h> /* for run_uncached() */
 
+#ifdef CONFIG_SOC_AU1X00
+#include <au1000.h>
+#endif
+
 /*
  * Must die.
  */
@@ -1203,6 +1207,16 @@ static inline void coherency_setup(void)
 {
 	change_c0_config(CONF_CM_CMASK, CONF_CM_DEFAULT);
 
+#ifdef CONFIG_SOC_AU1X00
+	/*
+	 * c0_config.od (bit 19) is write only (and reads as 0) on many early
+	 * revs of AMD Au1x00 SOCs. It disables the bus transaction overlapping 
+	 * and needs to be set to correct the various errata. So if it has been
+	 * set by the board setup code we must leave it set...
+	 */
+	if (cur_cpu_spec[0]->cpu_od)
+		set_c0_config(1 << 19);
+#endif
 	/*
 	 * c0_status.cu=0 specifies that updates by the sc instruction use
 	 * the coherency mode specified by the TLB; 1 means cachable