dma-mapping: add a dma_init_global_coherent helper

Add a new helper to initialize the global coherent pool.  This both
cleans up the existing initialization which indirects through the
reserved_mem_ops that are normally only used for struct device, and
also allows using the global pool for non-devicetree architectures.

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

diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index 2f84249..068f1b1 100644 (file)
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -177,7 +177,7 @@ void *dma_alloc_from_global_coherent(struct device *dev, ssize_t size,
 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)

diff --git a/kernel/dma/coherent.c b/kernel/dma/coherent.c
index ab397eb..160d4e2 100644 (file)
--- a/kernel/dma/coherent.c
+++ b/kernel/dma/coherent.c
@@ -300,6 +300,18 @@ int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *vaddr,
                                        vaddr, size, ret);
 }
 
+int dma_init_global_coherent(phys_addr_t phys_addr, size_t size)
+{
+       struct dma_coherent_mem *mem;
+
+       mem = dma_init_coherent_memory(phys_addr, phys_addr, size, true);
+       if (IS_ERR(mem))
+               return PTR_ERR(mem);
+       dma_coherent_default_memory = mem;
+       pr_info("DMA: default coherent area is set\n");
+       return 0;
+}
+
 /*
  * Support for reserved memory regions defined in device tree
  */
@@ -367,26 +379,10 @@ static int __init rmem_dma_setup(struct reserved_mem *rmem)
 
 static int __init dma_init_reserved_memory(void)
 {
-       const struct reserved_mem_ops *ops;
-       int ret;
-
        if (!dma_reserved_default_memory)
                return -ENOMEM;
-
-       ops = dma_reserved_default_memory->ops;
-
-       /*
-        * We rely on rmem_dma_device_init() does not propagate error of
-        * dma_assign_coherent_memory() for "NULL" device.
-        */
-       ret = ops->device_init(dma_reserved_default_memory, NULL);
-
-       if (!ret) {
-               dma_coherent_default_memory = dma_reserved_default_memory->priv;
-               pr_info("DMA: default coherent area is set\n");
-       }
-
-       return ret;
+       return dma_init_global_coherent(dma_reserved_default_memory->base,
+                                       dma_reserved_default_memory->size);
 }
 
 core_initcall(dma_init_reserved_memory);