ARM: dma-mapping: introduce the idea of buffer ownership
The DMA API has the notion of buffer ownership; make it explicit in the
ARM implementation of this API. This gives us a set of hooks to allow
us to deal with CPU cache issues arising from non-cache coherent DMA.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-By: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-By: Jamie Iles <jamie@jamieiles.com>
diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c
index bc90364..51499d6 100644
--- a/arch/arm/common/dmabounce.c
+++ b/arch/arm/common/dmabounce.c
@@ -277,7 +277,7 @@
* We don't need to sync the DMA buffer since
* it was allocated via the coherent allocators.
*/
- dma_cache_maint(ptr, size, dir);
+ __dma_single_cpu_to_dev(ptr, size, dir);
}
return dma_addr;
@@ -315,6 +315,8 @@
__cpuc_flush_kernel_dcache_area(ptr, size);
}
free_safe_buffer(dev->archdata.dmabounce, buf);
+ } else {
+ __dma_single_dev_to_cpu(dma_to_virt(dev, dma_addr), size, dir);
}
}