Add memory barriers wbflush, mb and iobarrier_rw

frno7 · Dec 15, 2020 · d4caf4c · d4caf4c
1 parent 0c2ed89
commit d4caf4c
Showing 1 changed file with 20 additions and 2 deletions.
diff --git a/include/iopmod/io.h b/include/iopmod/io.h
@@ -6,16 +6,34 @@
 #ifndef IOPMOD_IO_H
 #define IOPMOD_IO_H
 
+#include "iopmod/addrspace.h"
 #include "iopmod/types.h"
 
 /* Use I/O read and write with KSEG1. */
 
+/* Macro definition from the Linux kernel. */
+#define __fast_iob()							\
+	__asm__ __volatile__(						\
+		".set   push\n\t"					\
+		".set   noreorder\n\t"					\
+		"lw     $0,%0\n\t"					\
+		"nop\n\t"						\
+		".set   pop"						\
+		: /* No output. */					\
+		: "m" (*(int *)CKSEG1)					\
+		: "memory")
+
+#define wbflush() __fast_iob()
+
+#define mb()		wbflush()
+#define iobarrier_rw()	mb()
+
 #define DEFINE_IORD(type, name)						\
 static inline type name(const u32 addr)					\
 {									\
 	const volatile type *__addr = (const volatile type *)addr;	\
 									\
-	/* FIXME: Crashes? __sync_synchronize(); */			\
+	iobarrier_rw();							\
 									\
 	return *__addr;							\
 }
@@ -29,7 +47,7 @@ static inline void name(type value, u32 addr)				\
 {									\
 	volatile type *__addr = (volatile type *)addr;			\
 									\
-	/* FIXME: Crashes? __sync_synchronize(); */			\
+	iobarrier_rw();							\
 									\
 	*__addr = value;						\
 }