So we can share understanding of those barriers with other archs
and hopefully one day we will be able to switch asm-generic.
As mmiowb_set_pending is unimplemented on MIPS, __io_aw currently
does nothing, but it need to be implemented later.
Signed-off-by: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>
---
arch/mips/include/asm/io.h | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/arch/mips/include/asm/io.h b/arch/mips/include/asm/io.h
index 065e1ab6401a..8a148277d9e6 100644
--- a/arch/mips/include/asm/io.h
+++ b/arch/mips/include/asm/io.h
@@ -225,6 +225,17 @@ void iounmap(const volatile void __iomem *addr);
#define war_io_reorder_wmb() barrier()
#endif
+#define __io_br() mb()
+
+/* prevent prefetching of coherent DMA data ahead of a dma-complete */
+#define __io_ar(v) rmb()
+
+/* flush writes to coherent DMA data before possibly triggering a DMA read */
+#define __io_bw() wmb()
+
+/* serialize device access against a spin_unlock, usually handled there. */
+#define __io_aw() do { } while (0)
+
#define __BUILD_MEMORY_SINGLE(pfx, bwlq, type, barrier, relax, irq) \
\
static inline void pfx##write##bwlq(type val, \
@@ -234,7 +245,7 @@ static inline void pfx##write##bwlq(type val, \
type __val; \
\
if (barrier) \
- iobarrier_rw(); \
+ __io_bw(); \
else \
war_io_reorder_wmb(); \
\
@@ -265,6 +276,7 @@ static inline void pfx##write##bwlq(type val, \
local_irq_restore(__flags); \
} else \
BUG(); \
+ __io_aw(); \
} \
\
static inline type pfx##read##bwlq(const volatile void __iomem *mem) \
@@ -275,7 +287,7 @@ static inline type pfx##read##bwlq(const volatile void __iomem *mem) \
__mem = (void *)__swizzle_addr_##bwlq((unsigned long)(mem)); \
\
if (barrier) \
- iobarrier_rw(); \
+ __io_br(); \
\
if (sizeof(type) != sizeof(u64) || sizeof(u64) == sizeof(long)) \
__val = *__mem; \
@@ -300,9 +312,8 @@ static inline type pfx##read##bwlq(const volatile void __iomem *mem) \
BUG(); \
} \
\
- /* prevent prefetching of coherent DMA data prematurely */ \
if (!relax) \
- rmb(); \
+ io_ar(__val); \
return pfx##ioswab##bwlq(__mem, __val); \
}
--
2.35.1
