1 files changed, 43 insertions, 3 deletions

diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c
index efd71cf4fdea..f3deb6af42ad 100644
--- a/drivers/base/dma-mapping.c
+++ b/drivers/base/dma-mapping.c
@@ -7,9 +7,11 @@
  * This file is released under the GPLv2.
  */
 
+#include <linux/acpi.h>
 #include <linux/dma-mapping.h>
 #include <linux/export.h>
 #include <linux/gfp.h>
+#include <linux/of_device.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 
@@ -309,14 +311,13 @@ void *dma_common_contiguous_remap(struct page *page, size_t size,
 	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);
+	for (i = 0; i < (size >> PAGE_SHIFT); i++)
+		pages[i] = nth_page(page, i);
 
 	ptr = dma_common_pages_remap(pages, size, vm_flags, prot, caller);
 
@@ -341,3 +342,42 @@ void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags)
 	vunmap(cpu_addr);
 }
 #endif
+
+/*
+ * Common configuration to enable DMA API use for a device
+ */
+#include <linux/pci.h>
+
+int dma_configure(struct device *dev)
+{
+	struct device *bridge = NULL, *dma_dev = dev;
+	enum dev_dma_attr attr;
+	int ret = 0;
+
+	if (dev_is_pci(dev)) {
+		bridge = pci_get_host_bridge_device(to_pci_dev(dev));
+		dma_dev = bridge;
+		if (IS_ENABLED(CONFIG_OF) && dma_dev->parent &&
+		    dma_dev->parent->of_node)
+			dma_dev = dma_dev->parent;
+	}
+
+	if (dma_dev->of_node) {
+		ret = of_dma_configure(dev, dma_dev->of_node);
+	} else if (has_acpi_companion(dma_dev)) {
+		attr = acpi_get_dma_attr(to_acpi_device_node(dma_dev->fwnode));
+		if (attr != DEV_DMA_NOT_SUPPORTED)
+			ret = acpi_dma_configure(dev, attr);
+	}
+
+	if (bridge)
+		pci_put_host_bridge_device(bridge);
+
+	return ret;
+}
+
+void dma_deconfigure(struct device *dev)
+{
+	of_dma_deconfigure(dev);
+	acpi_dma_deconfigure(dev);
+}