set up dma_ops appropriately

This patch introduces a global pointer, dma_ops, which points to an
appropriate dma_mapping_ops that the kernel should use. This is a
common way to handle multiple dma_mapping_ops (X86, POWER, and SPARC).

dma_ops is set in platform_dma_init. We also set it by hand where
machvec_init is callev via subsys_initcall.

- IA64_DIG_VTD uses vtd_dma_ops.
- IA64_HP_ZX1 uses sba_dma_ops.
- IA64_HP_ZX1_SWIOTLB uses hwsw_dma_ops.
- IA64_SGI_SN2 uses sn_dma_ops.
- The rest use swiotlb_dma_ops.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 3 deletions

diff --git a/arch/ia64/kernel/pci-dma.c b/arch/ia64/kernel/pci-dma.c
index f8c38bd2c36..1c1224bd017 100644
--- a/arch/ia64/kernel/pci-dma.c
+++ b/arch/ia64/kernel/pci-dma.c
@@ -41,8 +41,11 @@ struct device fallback_dev = {
 	.dma_mask = &fallback_dev.coherent_dma_mask,
 };
 
+extern struct dma_mapping_ops vtd_dma_ops;
+
 void __init pci_iommu_alloc(void)
 {
+	dma_ops = &vtd_dma_ops;
 	/*
 	 * The order of these functions is important for
 	 * fall-back/fail-over reasons
@@ -76,9 +79,6 @@ iommu_dma_init(void)
 	return;
 }
 
-struct dma_mapping_ops *dma_ops;
-EXPORT_SYMBOL(dma_ops);
-
 int iommu_dma_supported(struct device *dev, u64 mask)
 {
 	struct dma_mapping_ops *ops = get_dma_ops(dev);