arm64 : Introduce support for ACPI _CCA object

section 6.2.17 _CCA states that ARM platforms require ACPI _CCA
object to be specified for DMA-cabpable devices. Therefore, this patch
specifies ACPI_CCA_REQUIRED in arm64 Kconfig.

In addition, to handle the case when _CCA is missing, arm64 would assign
dummy_dma_ops to disable DMA capability of the device.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 92 insertions, 0 deletions

diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index b0bd4e5fd5cf..d16a1cead23f 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -414,6 +414,98 @@ out:
 	return -ENOMEM;
 }
 
+/********************************************
+ * The following APIs are for dummy DMA ops *
+ ********************************************/
+
+static void *__dummy_alloc(struct device *dev, size_t size,
+			   dma_addr_t *dma_handle, gfp_t flags,
+			   struct dma_attrs *attrs)
+{
+	return NULL;
+}
+
+static void __dummy_free(struct device *dev, size_t size,
+			 void *vaddr, dma_addr_t dma_handle,
+			 struct dma_attrs *attrs)
+{
+}
+
+static int __dummy_mmap(struct device *dev,
+			struct vm_area_struct *vma,
+			void *cpu_addr, dma_addr_t dma_addr, size_t size,
+			struct dma_attrs *attrs)
+{
+	return -ENXIO;
+}
+
+static dma_addr_t __dummy_map_page(struct device *dev, struct page *page,
+				   unsigned long offset, size_t size,
+				   enum dma_data_direction dir,
+				   struct dma_attrs *attrs)
+{
+	return DMA_ERROR_CODE;
+}
+
+static void __dummy_unmap_page(struct device *dev, dma_addr_t dev_addr,
+			       size_t size, enum dma_data_direction dir,
+			       struct dma_attrs *attrs)
+{
+}
+
+static int __dummy_map_sg(struct device *dev, struct scatterlist *sgl,
+			  int nelems, enum dma_data_direction dir,
+			  struct dma_attrs *attrs)
+{
+	return 0;
+}
+
+static void __dummy_unmap_sg(struct device *dev,
+			     struct scatterlist *sgl, int nelems,
+			     enum dma_data_direction dir,
+			     struct dma_attrs *attrs)
+{
+}
+
+static void __dummy_sync_single(struct device *dev,
+				dma_addr_t dev_addr, size_t size,
+				enum dma_data_direction dir)
+{
+}
+
+static void __dummy_sync_sg(struct device *dev,
+			    struct scatterlist *sgl, int nelems,
+			    enum dma_data_direction dir)
+{
+}
+
+static int __dummy_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
+{
+	return 1;
+}
+
+static int __dummy_dma_supported(struct device *hwdev, u64 mask)
+{
+	return 0;
+}
+
+struct dma_map_ops dummy_dma_ops = {
+	.alloc                  = __dummy_alloc,
+	.free                   = __dummy_free,
+	.mmap                   = __dummy_mmap,
+	.map_page               = __dummy_map_page,
+	.unmap_page             = __dummy_unmap_page,
+	.map_sg                 = __dummy_map_sg,
+	.unmap_sg               = __dummy_unmap_sg,
+	.sync_single_for_cpu    = __dummy_sync_single,
+	.sync_single_for_device = __dummy_sync_single,
+	.sync_sg_for_cpu        = __dummy_sync_sg,
+	.sync_sg_for_device     = __dummy_sync_sg,
+	.mapping_error          = __dummy_mapping_error,
+	.dma_supported          = __dummy_dma_supported,
+};
+EXPORT_SYMBOL(dummy_dma_ops);
+
 static int __init arm64_dma_init(void)
 {
 	int ret;