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/drivers/Kconfig b/drivers/Kconfig
index 5ebc89d..64c2793 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -34,6 +34,8 @@
 
 source "drivers/power/Kconfig"
 
+source "drivers/ram/Kconfig"
+
 source "drivers/hwmon/Kconfig"
 
 source "drivers/watchdog/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index c090aba..4f859dc 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -11,6 +11,7 @@
 obj-y += misc/
 obj-y += pcmcia/
 obj-y += dfu/
+obj-$(CONFIG_RAM) += ram/
 obj-y += rtc/
 obj-y += sound/
 obj-y += tpm/
diff --git a/drivers/ram/Kconfig b/drivers/ram/Kconfig
new file mode 100644
index 0000000..642a2d8
--- /dev/null
+++ b/drivers/ram/Kconfig
@@ -0,0 +1,18 @@
+config RAM
+	bool "Enable RAM drivers using Driver Model"
+	depends on DM
+	help
+	  This allows drivers to be provided for SDRAM and other RAM
+	  controllers and their type to be specified in the board's device
+	  tree. Generally some parameters are required to set up the RAM and
+	  the RAM size can either be statically defined or dynamically
+	  detected.
+
+config SPL_RAM_SUPPORT
+	bool "Enable RAM support in SPL"
+	depends on RAM
+	help
+	  The RAM subsystem adds a small amount of overhead to the image.
+	  If this is acceptable and you have a need to use RAM drivers in
+	  SPL, enable this option. It might provide a cleaner interface to
+	  setting up RAM (e.g. SDRAM / DDR) within SPL.
diff --git a/drivers/ram/Makefile b/drivers/ram/Makefile
new file mode 100644
index 0000000..4494d81
--- /dev/null
+++ b/drivers/ram/Makefile
@@ -0,0 +1,7 @@
+#
+# Copyright (c) 2015 Google, Inc
+# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+#
+# SPDX-License-Identifier:      GPL-2.0+
+#
+obj-$(CONFIG_RAM) += ram-uclass.o
diff --git a/drivers/ram/ram-uclass.c b/drivers/ram/ram-uclass.c
new file mode 100644
index 0000000..2f1fbe7
--- /dev/null
+++ b/drivers/ram/ram-uclass.c
@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2015 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <ram.h>
+#include <dm.h>
+#include <errno.h>
+#include <dm/lists.h>
+#include <dm/root.h>
+
+int ram_get_info(struct udevice *dev, struct ram_info *info)
+{
+	struct ram_ops *ops = ram_get_ops(dev);
+
+	if (!ops->get_info)
+		return -ENOSYS;
+
+	return ops->get_info(dev, info);
+}
+
+UCLASS_DRIVER(ram) = {
+	.id		= UCLASS_RAM,
+	.name		= "ram",
+};