--- zzzz-none-000/linux-3.10.107/drivers/base/dma-mapping.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/drivers/base/dma-mapping.c	2021-02-04 17:41:59.000000000 +0000
@@ -10,6 +10,8 @@
 #include <linux/dma-mapping.h>
 #include <linux/export.h>
 #include <linux/gfp.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
 #include <asm-generic/dma-coherent.h>
 
 /*
@@ -60,7 +62,7 @@
  * RETURNS:
  * Pointer to allocated memory on success, NULL on failure.
  */
-void * dmam_alloc_coherent(struct device *dev, size_t size,
+void *dmam_alloc_coherent(struct device *dev, size_t size,
 			   dma_addr_t *dma_handle, gfp_t gfp)
 {
 	struct dma_devres *dr;
@@ -175,7 +177,7 @@
 /**
  * dmam_declare_coherent_memory - Managed dma_declare_coherent_memory()
  * @dev: Device to declare coherent memory for
- * @bus_addr: Bus address of coherent memory to be declared
+ * @phys_addr: Physical address of coherent memory to be declared
  * @device_addr: Device address of coherent memory to be declared
  * @size: Size of coherent memory to be declared
  * @flags: Flags
@@ -185,7 +187,7 @@
  * RETURNS:
  * 0 on success, -errno on failure.
  */
-int dmam_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
+int dmam_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
 				 dma_addr_t device_addr, size_t size, int flags)
 {
 	void *res;
@@ -195,7 +197,7 @@
 	if (!res)
 		return -ENOMEM;
 
-	rc = dma_declare_coherent_memory(dev, bus_addr, device_addr, size,
+	rc = dma_declare_coherent_memory(dev, phys_addr, device_addr, size,
 					 flags);
 	if (rc == 0)
 		devres_add(dev, res);
@@ -267,3 +269,73 @@
 	return ret;
 }
 EXPORT_SYMBOL(dma_common_mmap);
+
+#ifdef CONFIG_MMU
+/*
+ * remaps an array of PAGE_SIZE pages into another vm_area
+ * Cannot be used in non-sleeping contexts
+ */
+void *dma_common_pages_remap(struct page **pages, size_t size,
+			unsigned long vm_flags, pgprot_t prot,
+			const void *caller)
+{
+	struct vm_struct *area;
+
+	area = get_vm_area_caller(size, vm_flags, caller);
+	if (!area)
+		return NULL;
+
+	area->pages = pages;
+
+	if (map_vm_area(area, prot, pages)) {
+		vunmap(area->addr);
+		return NULL;
+	}
+
+	return area->addr;
+}
+
+/*
+ * remaps an allocated contiguous region into another vm_area.
+ * Cannot be used in non-sleeping contexts
+ */
+
+void *dma_common_contiguous_remap(struct page *page, size_t size,
+			unsigned long vm_flags,
+			pgprot_t prot, const void *caller)
+{
+	int i;
+	struct page **pages;
+	void *ptr;
+	unsigned long pfn;
+
+	pages = kmalloc(sizeof(struct page *) << get_order(size), GFP_KERNEL);
+	if (!pages)
+		return NULL;
+
+	for (i = 0, pfn = page_to_pfn(page); i < (size >> PAGE_SHIFT); i++)
+		pages[i] = pfn_to_page(pfn + i);
+
+	ptr = dma_common_pages_remap(pages, size, vm_flags, prot, caller);
+
+	kfree(pages);
+
+	return ptr;
+}
+
+/*
+ * unmaps a range previously mapped by dma_common_*_remap
+ */
+void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags)
+{
+	struct vm_struct *area = find_vm_area(cpu_addr);
+
+	if (!area || (area->flags & vm_flags) != vm_flags) {
+		WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
+		return;
+	}
+
+	unmap_kernel_range((unsigned long)cpu_addr, PAGE_ALIGN(size));
+	vunmap(cpu_addr);
+}
+#endif