dm: core: implement dev_map_physmem()

This API helps to map physical register addresss pace of device to
virtual address space easily. Its just a wrapper around map_physmem()
with MAP_NOCACHE flag.

Signed-off-by: Vignesh R <vigneshr@ti.com>
Suggested-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jagan Teki <jteki@openedev.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Jagan Teki <jteki@openedev.com>

drivers/core/device.c

@@ -10,6 +10,7 @@
  */
 
 #include <common.h>
+#include <asm/io.h>
 #include <fdtdec.h>
 #include <fdt_support.h>
 #include <malloc.h>
@@ -697,6 +698,16 @@ void *dev_get_addr_ptr(struct udevice *dev)
 	return (void *)(uintptr_t)dev_get_addr_index(dev, 0);
 }
 
+void *dev_map_physmem(struct udevice *dev, unsigned long size)
+{
+	fdt_addr_t addr = dev_get_addr(dev);
+
+	if (addr == FDT_ADDR_T_NONE)
+		return NULL;
+
+	return map_physmem(addr, size, MAP_NOCACHE);
+}
+
 bool device_has_children(struct udevice *dev)
 {
 	return !list_empty(&dev->child_head);