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, 9 insertions, 0 deletions

diff --git a/arch/ia64/hp/common/sba_iommu.c b/arch/ia64/hp/common/sba_iommu.c
index 655b9a17db93..e82870a76801 100644
--- a/arch/ia64/hp/common/sba_iommu.c
+++ b/arch/ia64/hp/common/sba_iommu.c
@@ -2065,6 +2065,8 @@ static struct acpi_driver acpi_sba_ioc_driver = {
         },
 };
 
+extern struct dma_mapping_ops swiotlb_dma_ops;
+
 static int __init
 sba_init(void)
 {
@@ -2078,6 +2080,7 @@ sba_init(void)
          * a successful kdump kernel boot is to use the swiotlb.
          */
         if (is_kdump_kernel()) {
+                dma_ops = &swiotlb_dma_ops;
                 if (swiotlb_late_init_with_default_size(64 * (1<<20)) != 0)
                         panic("Unable to initialize software I/O TLB:"
                                   " Try machvec=dig boot option");
@@ -2093,6 +2096,7 @@ sba_init(void)
                  * If we didn't find something sba_iommu can claim, we
                  * need to setup the swiotlb and switch to the dig machvec.
                  */
+                dma_ops = &swiotlb_dma_ops;
                 if (swiotlb_late_init_with_default_size(64 * (1<<20)) != 0)
                         panic("Unable to find SBA IOMMU or initialize "
                               "software I/O TLB: Try machvec=dig boot option");
@@ -2196,3 +2200,8 @@ struct dma_mapping_ops sba_dma_ops = {
         .dma_supported_op       = sba_dma_supported,
         .mapping_error          = sba_dma_mapping_error,
 };
+
+void sba_dma_init(void)
+{
+        dma_ops = &sba_dma_ops;
+}