Usually dma_supported decisions are done by the dma_map_ops instance.
Switch sparc to that model by providing a ->dma_supported instance for
sbus that always returns false, and implementations tailored to the sun4u
and sun4v cases for sparc64, and leave it unimplemented for PCI on
sparc32, which means always supported.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/sparc/include/asm/dma-mapping.h |  3 ---
 arch/sparc/kernel/iommu.c            | 40 +++++++++++++++---------------------
 arch/sparc/kernel/ioport.c           | 22 ++++++--------------
 arch/sparc/kernel/pci_sun4v.c        | 17 +++++++++++++++
 4 files changed, 39 insertions(+), 43 deletions(-)

diff --git a/arch/sparc/kernel/ioport.c b/arch/sparc/kernel/ioport.c
index dd081d557609..12894f259bea 100644
--- a/arch/sparc/kernel/ioport.c
+++ b/arch/sparc/kernel/ioport.c

@@ -401,6 +401,11 @@ static void sbus_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
        BUG();
 }

+static int sbus_dma_supported(struct device *dev, u64 mask)
+{
+       return 0;
+}
+

 static const struct dma_map_ops sbus_dma_ops = {
        .alloc                  = sbus_alloc_coherent,
        .free                   = sbus_free_coherent,

@@ -410,6 +415,7 @@ static const struct dma_map_ops sbus_dma_ops = {
        .unmap_sg               = sbus_unmap_sg,
        .sync_sg_for_cpu        = sbus_sync_sg_for_cpu,
        .sync_sg_for_device     = sbus_sync_sg_for_device,
+       .dma_supported          = sbus_dma_supported,
 };

 static int __init sparc_register_ioport(void)