[U-Boot] [RFC PATCH 17/19] x86: Add initial memory barrier macros

[Simon Glass]

These are available on other architecures, so add them on x86.

Signed-off-by: Simon Glass <sjg at chromium.org>
---
 arch/x86/include/asm/io.h |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
index 9b757d4..b12bdd8 100644
--- a/arch/x86/include/asm/io.h
+++ b/arch/x86/include/asm/io.h
@@ -234,4 +234,12 @@ static inline phys_addr_t virt_to_phys(void * vaddr)
 	return (phys_addr_t)(vaddr);
 }
 
+/*
+ * TODO: The kernel offers some more advanced versions of barriers, it might
+ * have some advantages to use them instead of the simple one here.
+ */
+#define dmb()		__asm__ __volatile__ ("" : : : "memory")
+#define __iormb()	dmb()
+#define __iowmb()	dmb()
+
 #endif
-- 
1.7.3.1