[IA64-SGI] volatile semantics in places where it seems necessary

Resend using accessors instead of volatile qualifiers per hch comments, and
easier to understand convenience macros per rja comments.

Patch to apply volatile semantics when accessing MMR's in various SN files.

Signed-off-by: Mark Maule <maule@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/include/asm-ia64/sn/io.h b/include/asm-ia64/sn/io.h
index 42209733f6b1..7597a52b426c 100644
--- a/include/asm-ia64/sn/io.h
+++ b/include/asm-ia64/sn/io.h
@@ -36,6 +36,15 @@ extern void sn_dma_flush(unsigned long);
 #define __sn_readq_relaxed ___sn_readq_relaxed
 
 /*
+ * Convenience macros for setting/clearing bits using the above accessors
+ */
+
+#define __sn_setq_relaxed(addr, val) \
+        writeq((__sn_readq_relaxed(addr) | (val)), (addr))
+#define __sn_clrq_relaxed(addr, val) \
+        writeq((__sn_readq_relaxed(addr) & ~(val)), (addr))
+
+/*
  * The following routines are SN Platform specific, called when
  * a reference is made to inX/outX set macros.  SN Platform
  * inX set of macros ensures that Posted DMA writes on the