[PATCH v9 08/18] arm/xen: get_dma_ops: return xen_dma_ops if we are running as xen_initial_domain

From: Stefano Stabellini
Date: Fri Oct 25 2013 - 06:53:56 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>
Suggested-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Acked-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
CC: will.deacon@xxxxxxx
CC: linux@xxxxxxxxxxxxxxxx

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

diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index 01b5a3d..f5945d4 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -12,17 +12,28 @@
#include <asm/memory.h>
#include <asm/cacheflush.h>

+#include <xen/xen.h>
+#include <asm/xen/hypervisor.h>
+
#define DMA_ERROR_CODE (~0)
extern struct dma_map_ops arm_dma_ops;
extern struct dma_map_ops arm_coherent_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 (dev && dev->archdata.dma_ops)
return dev->archdata.dma_ops;
return &arm_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);
+}
+
static inline void set_dma_ops(struct device *dev, struct dma_map_ops *ops)
{
BUG_ON(!dev);
--
1.7.2.5

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