Introduce the dma_flags_set/get_*() interfaces and give them
default implementations.
Architectures which allow DMA to be reordered between a device and
host memory (within a NUMA interconnect) can redefine these to allow
a driver to explicitly synchronize DMA from the device when necessary.
Signed-off-by: Arthur Kepner <[email protected]>
---
Andrew, this is the first in a series of three patches:
[1/3] dma: add dma_flags_set/get_*() interfaces
[2/3] dma: redefine dma_flags_set/get_*() for sn-ia64
[3/3] dma: document dma_flags_set/get_*()
Variants of these patches have been discussed on several
occasions, most recently in a thread beginning:
http://marc.info/?l=linux-kernel&m=119137949604365&w=2
Please consider this for 2.6.24.
Jes, Tony, please note that I added an explicit test for
CONFIG_IA64_SGI_SN2 in asm-ia64/sn/io.h (Yuck). This is
needed for IA64_GENERIC to build, since there's at least one
driver (qla1280) that includes asm-ia64/sn/io.h for
CONFIG_IA64_GENERIC.
dma-mapping.h | 18 ++++++++++++++++++
1 files changed, 18 insertions(+)
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 0ebfafb..132b559 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -106,4 +106,22 @@ static inline void dmam_release_declared_memory(struct device *dev)
}
#endif /* ARCH_HAS_DMA_DECLARE_COHERENT_MEMORY */
+#define DMA_BARRIER_ATTR 0x1
+#ifndef ARCH_USES_DMA_ATTRS
+static inline int dma_flags_set_attr(u32 attr, enum dma_data_direction dir)
+{
+ return dir;
+}
+
+static inline int dma_flags_get_dir(int flags)
+{
+ return flags;
+}
+
+static inline int dma_flags_get_attr(int flags)
+{
+ return 0;
+}
+#endif /* ARCH_USES_DMA_ATTRS */
+
#endif
-
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