[PATCH v9 09/18] arm64/xen: get_dma_ops: return xen_dma_ops if we are running as xen_initial_domain

From: Stefano Stabellini
Date: Fri Oct 25 2013 - 06:54:42 EST

We can't simply override arm_dma_ops with xen_dma_ops because devices
are allowed to have their own dma_ops and they take precedence over
arm_dma_ops. When running on Xen as initial domain, we always want
xen_dma_ops to be the one in use.

We introduce __generic_dma_ops to allow xen_dma_ops functions to call
back to the native implementation.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
CC: will.deacon@xxxxxxx

Changes in v7:
- return xen_dma_ops only if we are the initial domain;
- rename __get_dma_ops to __generic_dma_ops.
arch/arm64/include/asm/dma-mapping.h | 13 ++++++++++++-
1 files changed, 12 insertions(+), 1 deletions(-)

diff --git a/arch/arm64/include/asm/dma-mapping.h b/arch/arm64/include/asm/dma-mapping.h
index 59206b1..fd0c0c0 100644
--- a/arch/arm64/include/asm/dma-mapping.h
+++ b/arch/arm64/include/asm/dma-mapping.h
@@ -23,12 +23,15 @@

#include <asm-generic/dma-coherent.h>

+#include <xen/xen.h>
+#include <asm/xen/hypervisor.h>

#define DMA_ERROR_CODE (~(dma_addr_t)0)
extern struct dma_map_ops *dma_ops;

-static inline struct dma_map_ops *get_dma_ops(struct device *dev)
+static inline struct dma_map_ops *__generic_dma_ops(struct device *dev)
if (unlikely(!dev) || !dev->archdata.dma_ops)
return dma_ops;
@@ -36,6 +39,14 @@ static inline struct dma_map_ops *get_dma_ops(struct device *dev)
return dev->archdata.dma_ops;

+static inline struct dma_map_ops *get_dma_ops(struct device *dev)
+ if (xen_initial_domain())
+ return xen_dma_ops;
+ else
+ return __generic_dma_ops(dev);
#include <asm-generic/dma-mapping-common.h>

static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)

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