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>

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 7796af4b1d6f65f6352ed40cd6dfcaf580cfd63d..6be1a6efcdd64de03714e84d0343c132295307e3 100644 (file)
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1,5 +1,6 @@
 config ARM64
        def_bool y
+       select ACPI_CCA_REQUIRED if ACPI
        select ACPI_GENERIC_GSI if ACPI
        select ACPI_REDUCED_HARDWARE_ONLY if ACPI
        select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE

diff --git a/arch/arm64/include/asm/dma-mapping.h b/arch/arm64/include/asm/dma-mapping.h
index 9437e3dc58338ea4c48b9b6afe24d62bc09a7c79..f0d6d0bfe55ceceba3339bc9044bed31a159a9cf 100644 (file)
--- a/arch/arm64/include/asm/dma-mapping.h
+++ b/arch/arm64/include/asm/dma-mapping.h
@@ -18,6 +18,7 @@
 
 #ifdef __KERNEL__
 
+#include <linux/acpi.h>
 #include <linux/types.h>
 #include <linux/vmalloc.h>
 
@@ -28,13 +29,23 @@
 
 #define DMA_ERROR_CODE (~(dma_addr_t)0)
 extern struct dma_map_ops *dma_ops;
+extern struct dma_map_ops dummy_dma_ops;
 
 static inline struct dma_map_ops *__generic_dma_ops(struct device *dev)
 {
-       if (unlikely(!dev) || !dev->archdata.dma_ops)
+       if (unlikely(!dev))
                return dma_ops;
-       else
+       else if (dev->archdata.dma_ops)
                return dev->archdata.dma_ops;
+       else if (acpi_disabled)
+               return dma_ops;
+
+       /*
+        * When ACPI is enabled, if arch_set_dma_ops is not called,
+        * we will disable device DMA capability by setting it
+        * to dummy_dma_ops.
+        */
+       return &dummy_dma_ops;
 }
 
 static inline struct dma_map_ops *get_dma_ops(struct device *dev)
@@ -48,6 +59,9 @@ static inline struct dma_map_ops *get_dma_ops(struct device *dev)
 static inline void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
                                      struct iommu_ops *iommu, bool coherent)
 {
+       if (!acpi_disabled && !dev->archdata.dma_ops)
+               dev->archdata.dma_ops = dma_ops;
+
        dev->archdata.dma_coherent = coherent;
 }
 #define arch_setup_dma_ops     arch_setup_dma_ops

diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index b0bd4e5fd5cf9c2599ddbc509bccb233838638a4..d16a1cead23f1c3b489d320bcb0ac7d1d461621d 100644 (file)
--- 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;