dm: Add support for RAM drivers

Add support for a driver which sets up DRAM and can return information about
the amount of RAM available. This is a first step towards moving RAM init
to driver model.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/ram.h b/include/ram.h
new file mode 100644
index 0000000..e2172a8
--- /dev/null
+++ b/include/ram.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2015 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __RAM_H
+#define __RAM_H
+
+struct ram_info {
+	phys_addr_t base;
+	size_t size;
+};
+
+struct ram_ops {
+	/**
+	 * get_info() - Get basic memory info
+	 *
+	 * @dev:	Device to check (UCLASS_RAM)
+	 * @info:	Place to put info
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*get_info)(struct udevice *dev, struct ram_info *info);
+};
+
+#define ram_get_ops(dev)        ((struct ram_ops *)(dev)->driver->ops)
+
+/**
+ * ram_get_info() - Get information about a RAM device
+ *
+ * @dev:	Device to check (UCLASS_RAM)
+ * @info:	Returns RAM info
+ * @return 0 if OK, -ve on error
+ */
+int ram_get_info(struct udevice *dev, struct ram_info *info);
+
+#endif