arm: dma-mapping: plumb our iommu mapping ops into arch_setup_dma_ops

This patch plumbs the existing ARM IOMMU DMA infrastructure (which isn't
actually called outside of a few drivers) into arch_setup_dma_ops, so
that we can use IOMMUs for DMA transfers in a more generic fashion.

Since this significantly complicates the arch_setup_dma_ops function,
it is moved out of line into dma-mapping.c. If CONFIG_ARM_DMA_USE_IOMMU
is not set, the iommu parameter is ignored and the normal ops are used
instead.

Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index f3c0d953f6a210c6612b03aad7ff6d33b1fc74ef..9410b7e548fc7129857c1fa03596a5b86261e1ee 100644 (file)
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -121,14 +121,12 @@ static inline unsigned long dma_max_pfn(struct device *dev)
 }
 #define dma_max_pfn(dev) dma_max_pfn(dev)
 
-static inline void arch_setup_dma_ops(struct device *dev, u64 dma_base,
-                                     u64 size, struct iommu_ops *iommu,
-                                     bool coherent)
-{
-       if (coherent)
-               set_dma_ops(dev, &arm_coherent_dma_ops);
-}
 #define arch_setup_dma_ops arch_setup_dma_ops
+extern void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
+                              struct iommu_ops *iommu, bool coherent);
+
+#define arch_teardown_dma_ops arch_teardown_dma_ops
+extern void arch_teardown_dma_ops(struct device *dev);
 
 static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
 {

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index e8907117861ef81a79938df32b1889a80e7cdc5a..09645f00bd17573261c94788ff9712971969dcf5 100644 (file)
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1947,9 +1947,8 @@ EXPORT_SYMBOL_GPL(arm_iommu_release_mapping);
  *     arm_iommu_create_mapping)
  *
  * Attaches specified io address space mapping to the provided device,
- * this replaces the dma operations (dma_map_ops pointer) with the
- * IOMMU aware version. More than one client might be attached to
- * the same io address space mapping.
+ * More than one client might be attached to the same io address space
+ * mapping.
  */
 int arm_iommu_attach_device(struct device *dev,
                            struct dma_iommu_mapping *mapping)
@@ -1962,7 +1961,6 @@ int arm_iommu_attach_device(struct device *dev,
 
        kref_get(&mapping->kref);
        dev->archdata.mapping = mapping;
-       set_dma_ops(dev, &iommu_ops);
 
        pr_debug("Attached IOMMU controller to %s device.\n", dev_name(dev));
        return 0;
@@ -1974,7 +1972,6 @@ EXPORT_SYMBOL_GPL(arm_iommu_attach_device);
  * @dev: valid struct device pointer
  *
  * Detaches the provided device from a previously attached map.
- * This voids the dma operations (dma_map_ops pointer)
  */
 void arm_iommu_detach_device(struct device *dev)
 {
@@ -1989,10 +1986,82 @@ void arm_iommu_detach_device(struct device *dev)
        iommu_detach_device(mapping->domain, dev);
        kref_put(&mapping->kref, release_iommu_mapping);
        dev->archdata.mapping = NULL;
-       set_dma_ops(dev, NULL);
 
        pr_debug("Detached IOMMU controller from %s device.\n", dev_name(dev));
 }
 EXPORT_SYMBOL_GPL(arm_iommu_detach_device);
 
-#endif
+static struct dma_map_ops *arm_get_iommu_dma_map_ops(bool coherent)
+{
+       return coherent ? &iommu_coherent_ops : &iommu_ops;
+}
+
+static bool arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size,
+                                   struct iommu_ops *iommu)
+{
+       struct dma_iommu_mapping *mapping;
+
+       if (!iommu)
+               return false;
+
+       mapping = arm_iommu_create_mapping(dev->bus, dma_base, size);
+       if (IS_ERR(mapping)) {
+               pr_warn("Failed to create %llu-byte IOMMU mapping for device %s\n",
+                               size, dev_name(dev));
+               return false;
+       }
+
+       if (arm_iommu_attach_device(dev, mapping)) {
+               pr_warn("Failed to attached device %s to IOMMU_mapping\n",
+                               dev_name(dev));
+               arm_iommu_release_mapping(mapping);
+               return false;
+       }
+
+       return true;
+}
+
+static void arm_teardown_iommu_dma_ops(struct device *dev)
+{
+       struct dma_iommu_mapping *mapping = dev->archdata.mapping;
+
+       arm_iommu_detach_device(dev);
+       arm_iommu_release_mapping(mapping);
+}
+
+#else
+
+static bool arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size,
+                                   struct iommu_ops *iommu)
+{
+       return false;
+}
+
+static void arm_teardown_iommu_dma_ops(struct device *dev) { }
+
+#define arm_get_iommu_dma_map_ops arm_get_dma_map_ops
+
+#endif /* CONFIG_ARM_DMA_USE_IOMMU */
+
+static struct dma_map_ops *arm_get_dma_map_ops(bool coherent)
+{
+       return coherent ? &arm_coherent_dma_ops : &arm_dma_ops;
+}
+
+void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
+                       struct iommu_ops *iommu, bool coherent)
+{
+       struct dma_map_ops *dma_ops;
+
+       if (arm_setup_iommu_dma_ops(dev, dma_base, size, iommu))
+               dma_ops = arm_get_iommu_dma_map_ops(coherent);
+       else
+               dma_ops = arm_get_dma_map_ops(coherent);
+
+       set_dma_ops(dev, dma_ops);
+}
+
+void arch_teardown_dma_ops(struct device *dev)
+{
+       arm_teardown_iommu_dma_ops(dev);
+}