dma-mapping: make the global coherent pool conditional

Only build the code to support the global coherent pool if support for
it is enabled.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Dillon Min <dillon.minfei@gmail.com>

Author: Christoph Hellwig

include/linux/dma-map-ops.h

@@ -171,13 +171,6 @@ int dma_alloc_from_dev_coherent(struct device *dev, ssize_t size,
 int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr);
 int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma,
 		void *cpu_addr, size_t size, int *ret);
-
-void *dma_alloc_from_global_coherent(struct device *dev, ssize_t size,
-		dma_addr_t *dma_handle);
-int dma_release_from_global_coherent(int order, void *vaddr);
-int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *cpu_addr,
-		size_t size, int *ret);
-int dma_init_global_coherent(phys_addr_t phys_addr, size_t size);
 #else
 static inline int dma_declare_coherent_memory(struct device *dev,
 		phys_addr_t phys_addr, dma_addr_t device_addr, size_t size)
@@ -187,7 +180,16 @@ static inline int dma_declare_coherent_memory(struct device *dev,
 #define dma_alloc_from_dev_coherent(dev, size, handle, ret) (0)
 #define dma_release_from_dev_coherent(dev, order, vaddr) (0)
 #define dma_mmap_from_dev_coherent(dev, vma, vaddr, order, ret) (0)
+#endif /* CONFIG_DMA_DECLARE_COHERENT */
 
+#ifdef CONFIG_DMA_GLOBAL_POOL
+void *dma_alloc_from_global_coherent(struct device *dev, ssize_t size,
+		dma_addr_t *dma_handle);
+int dma_release_from_global_coherent(int order, void *vaddr);
+int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *cpu_addr,
+		size_t size, int *ret);
+int dma_init_global_coherent(phys_addr_t phys_addr, size_t size);
+#else
 static inline void *dma_alloc_from_global_coherent(struct device *dev,
 		ssize_t size, dma_addr_t *dma_handle)
 {
@@ -202,7 +204,7 @@ static inline int dma_mmap_from_global_coherent(struct vm_area_struct *vma,
 {
 	return 0;
 }
-#endif /* CONFIG_DMA_DECLARE_COHERENT */
+#endif /* CONFIG_DMA_GLOBAL_POOL */
 
 /*
  * This is the actual return value from the ->alloc_noncontiguous method.

kernel/dma/coherent.c

@@ -20,8 +20,6 @@ struct dma_coherent_mem {
 	bool		use_dev_dma_pfn_offset;
 };
 
-static struct dma_coherent_mem *dma_coherent_default_memory __ro_after_init;
-
 static inline struct dma_coherent_mem *dev_get_coherent_memory(struct device *dev)
 {
 	if (dev && dev->dma_mem)
@@ -191,16 +189,6 @@ int dma_alloc_from_dev_coherent(struct device *dev, ssize_t size,
 	return 1;
 }
 
-void *dma_alloc_from_global_coherent(struct device *dev, ssize_t size,
-				     dma_addr_t *dma_handle)
-{
-	if (!dma_coherent_default_memory)
-		return NULL;
-
-	return __dma_alloc_from_coherent(dev, dma_coherent_default_memory, size,
-					 dma_handle);
-}
-
 static int __dma_release_from_coherent(struct dma_coherent_mem *mem,
 				       int order, void *vaddr)
 {
@@ -236,15 +224,6 @@ int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr)
 	return __dma_release_from_coherent(mem, order, vaddr);
 }
 
-int dma_release_from_global_coherent(int order, void *vaddr)
-{
-	if (!dma_coherent_default_memory)
-		return 0;
-
-	return __dma_release_from_coherent(dma_coherent_default_memory, order,
-			vaddr);
-}
-
 static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
 		struct vm_area_struct *vma, void *vaddr, size_t size, int *ret)
 {
@@ -290,6 +269,28 @@ int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma,
 	return __dma_mmap_from_coherent(mem, vma, vaddr, size, ret);
 }
 
+#ifdef CONFIG_DMA_GLOBAL_POOL
+static struct dma_coherent_mem *dma_coherent_default_memory __ro_after_init;
+
+void *dma_alloc_from_global_coherent(struct device *dev, ssize_t size,
+				     dma_addr_t *dma_handle)
+{
+	if (!dma_coherent_default_memory)
+		return NULL;
+
+	return __dma_alloc_from_coherent(dev, dma_coherent_default_memory, size,
+					 dma_handle);
+}
+
+int dma_release_from_global_coherent(int order, void *vaddr)
+{
+	if (!dma_coherent_default_memory)
+		return 0;
+
+	return __dma_release_from_coherent(dma_coherent_default_memory, order,
+			vaddr);
+}
+
 int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *vaddr,
 				   size_t size, int *ret)
 {
@@ -311,6 +312,7 @@ int dma_init_global_coherent(phys_addr_t phys_addr, size_t size)
 	pr_info("DMA: default coherent area is set\n");
 	return 0;
 }
+#endif /* CONFIG_DMA_GLOBAL_POOL */
 
 /*
  * Support for reserved memory regions defined in device tree
@@ -320,7 +322,9 @@ int dma_init_global_coherent(phys_addr_t phys_addr, size_t size)
 #include <linux/of_fdt.h>
 #include <linux/of_reserved_mem.h>
 
+#ifdef CONFIG_DMA_GLOBAL_POOL
 static struct reserved_mem *dma_reserved_default_memory __initdata;
+#endif
 
 static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
 {
@@ -377,15 +381,16 @@ static int __init rmem_dma_setup(struct reserved_mem *rmem)
 	return 0;
 }
 
+#ifdef CONFIG_DMA_GLOBAL_POOL
 static int __init dma_init_reserved_memory(void)
 {
 	if (!dma_reserved_default_memory)
 		return -ENOMEM;
 	return dma_init_global_coherent(dma_reserved_default_memory->base,
 					dma_reserved_default_memory->size);
 }
-
 core_initcall(dma_init_reserved_memory);
+#endif /* CONFIG_DMA_GLOBAL_POOL */
 
 RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);
 #endif