[dpdk-dev] [PATCH v2 1/8] eal: introduce DMA memory barriers

[Yongseok Koh]

This commit introduces rte_dma_wmb() and rte_dma_rmb(), in order to
guarantee the ordering of coherent shared memory between the CPU and a DMA
capable device.

Signed-off-by: Yongseok Koh <yskoh at mellanox.com>
---
 lib/librte_eal/common/include/generic/rte_atomic.h | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/lib/librte_eal/common/include/generic/rte_atomic.h b/lib/librte_eal/common/include/generic/rte_atomic.h
index 16af5ca57..2e0503ce6 100644
--- a/lib/librte_eal/common/include/generic/rte_atomic.h
+++ b/lib/librte_eal/common/include/generic/rte_atomic.h
@@ -98,6 +98,24 @@ static inline void rte_io_wmb(void);
  */
 static inline void rte_io_rmb(void);
 
+/**
+ * Write memory barrier for coherent memory between lcore and IO device
+ *
+ * Guarantees that the STORE operations on coherent memory that
+ * precede the rte_dma_wmb() call are visible to I/O device before the
+ * STORE operations that follow it.
+ */
+static inline void rte_dma_wmb(void);
+
+/**
+ * Read memory barrier for coherent memory between lcore and IO device
+ *
+ * Guarantees that the LOAD operations on coherent memory updated by
+ * IO device that precede the rte_dma_rmb() call are visible to CPU
+ * before the LOAD operations that follow it.
+ */
+static inline void rte_dma_rmb(void);
+
 #endif /* __DOXYGEN__ */
 
 /**
-- 
2.11.0