Patchwork [U-Boot,v6,08/17] dm: Add base driver model support

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Submitter Simon Glass
Date Nov. 7, 2013, 4:32 p.m.
Message ID <1383841933-1800-9-git-send-email-sjg@chromium.org>
Download mbox | patch
Permalink /patch/289429/
State Superseded
Delegated to: Tom Rini
Headers show

Comments

Simon Glass - Nov. 7, 2013, 4:32 p.m.
Add driver model functionality for generic board.

This includes data structures and base code for registering devices and
uclasses (groups of devices with the same purpose, e.g. all I2C ports will
be in the same uclass).

The feature is enabled with CONFIG_DM.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Pavel Herrmann <morpheus.ibis@gmail.com>
Signed-off-by: Viktor Křivák <viktor.krivak@gmail.com>
Signed-off-by: Tomas Hlavacek <tmshlvck@gmail.com>
---
Changes in v6:
- Add dev_get_platdata to access devices's platdata
- Add dev_get_priv() to access device's private data
- Add ofdata_to_pdata method to convert device tree data to platdata
- Convert Makefiles to new Kconfig format
- Rename platform_data to platdata

Changes in v5:
- Change to new SPDX license headers
- Correct >80col line missed last time

Changes in v4:
- Move common/dm to drivers/core
- device_chld_unbind() continues on error

Changes in v3:
- Add a flag for tracking whether DM allocates/frees platform_data
- Rename per_device_priv_size to per_device_auto_alloc_size, etc.
- Tidy up commenting of functions and structures

Changes in v2: None

 Makefile                          |   1 +
 drivers/core/Makefile             |   7 +
 drivers/core/device.c             | 348 ++++++++++++++++++++++++++++++++++++++
 drivers/core/lists.c              | 155 +++++++++++++++++
 drivers/core/root.c               | 102 +++++++++++
 drivers/core/uclass.c             | 285 +++++++++++++++++++++++++++++++
 drivers/core/util.c               |  37 ++++
 include/asm-generic/global_data.h |   8 +
 include/dm.h                      |  14 ++
 include/dm/device-internal.h      |  87 ++++++++++
 include/dm/device.h               | 159 +++++++++++++++++
 include/dm/lists.h                |  39 +++++
 include/dm/platdata.h             |  22 +++
 include/dm/root.h                 |  53 ++++++
 include/dm/uclass-id.h            |  28 +++
 include/dm/uclass-internal.h      |  85 ++++++++++
 include/dm/uclass.h               | 142 ++++++++++++++++
 include/dm/util.h                 |  29 ++++
 18 files changed, 1601 insertions(+)
 create mode 100644 drivers/core/Makefile
 create mode 100644 drivers/core/device.c
 create mode 100644 drivers/core/lists.c
 create mode 100644 drivers/core/root.c
 create mode 100644 drivers/core/uclass.c
 create mode 100644 drivers/core/util.c
 create mode 100644 include/dm.h
 create mode 100644 include/dm/device-internal.h
 create mode 100644 include/dm/device.h
 create mode 100644 include/dm/lists.h
 create mode 100644 include/dm/platdata.h
 create mode 100644 include/dm/root.h
 create mode 100644 include/dm/uclass-id.h
 create mode 100644 include/dm/uclass-internal.h
 create mode 100644 include/dm/uclass.h
 create mode 100644 include/dm/util.h

Patch

diff --git a/Makefile b/Makefile
index 445b0b2..6e3eb8c 100644
--- a/Makefile
+++ b/Makefile
@@ -299,6 +299,7 @@  LIBS-y += lib/libfdt/libfdt.o
 LIBS-y += api/libapi.o
 LIBS-y += post/libpost.o
 LIBS-y += test/libtest.o
+LIBS-$(CONFIG_DM) += drivers/core/libdm.o
 
 ifneq (,$(filter $(SOC), mx25 mx27 mx5 mx6 mx31 mx35 mxs vf610))
 LIBS-y += arch/$(ARCH)/imx-common/libimx-common.o
diff --git a/drivers/core/Makefile b/drivers/core/Makefile
new file mode 100644
index 0000000..90b2a7f
--- /dev/null
+++ b/drivers/core/Makefile
@@ -0,0 +1,7 @@ 
+#
+# Copyright (c) 2013 Google, Inc
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+obj-$(CONFIG_DM)	:= device.o lists.o root.o uclass.o util.o
diff --git a/drivers/core/device.c b/drivers/core/device.c
new file mode 100644
index 0000000..55ba281
--- /dev/null
+++ b/drivers/core/device.c
@@ -0,0 +1,348 @@ 
+/*
+ * Device manager
+ *
+ * Copyright (c) 2013 Google, Inc
+ *
+ * (C) Copyright 2012
+ * Pavel Herrmann <morpheus.ibis@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <malloc.h>
+#include <dm/device.h>
+#include <dm/device-internal.h>
+#include <dm/lists.h>
+#include <dm/platdata.h>
+#include <dm/uclass.h>
+#include <dm/uclass-internal.h>
+#include <dm/util.h>
+#include <linux/err.h>
+#include <linux/list.h>
+
+/**
+ * device_chld_unbind() - Unbind all device's children from the device
+ *
+ * On error, the function continues to unbind all children, and reports the
+ * first error.
+ *
+ * @dev:	The device that is to be stripped of its children
+ * @return 0 on success, -ve on error
+ */
+static int device_chld_unbind(struct device *dev)
+{
+	struct device *pos, *n;
+	int ret, saved_ret = 0;
+
+	assert(dev);
+
+	list_for_each_entry_safe(pos, n, &dev->child_head, sibling_node) {
+		ret = device_unbind(pos);
+		if (ret && !saved_ret)
+			saved_ret = ret;
+	}
+
+	return saved_ret;
+}
+
+/**
+ * device_chld_remove() - Stop all device's children
+ * @dev:	The device whose children are to be removed
+ * @return 0 on success, -ve on error
+ */
+static int device_chld_remove(struct device *dev)
+{
+	struct device *pos, *n;
+	int ret;
+
+	assert(dev);
+
+	list_for_each_entry_safe(pos, n, &dev->child_head, sibling_node) {
+		ret = device_remove(pos);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+int device_bind(struct device *parent, struct driver *drv, const char *name,
+		void *platdata, int of_offset, struct device **devp)
+{
+	struct device *dev;
+	struct uclass *uc;
+	int ret = 0;
+
+	*devp = NULL;
+	if (!name)
+		return -EINVAL;
+
+	ret = uclass_get(drv->id, &uc);
+	if (ret)
+		return ret;
+
+	dev = calloc(1, sizeof(struct device));
+	if (!dev)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&dev->sibling_node);
+	INIT_LIST_HEAD(&dev->child_head);
+	INIT_LIST_HEAD(&dev->uclass_node);
+	dev->platdata = platdata;
+	dev->name = name;
+	dev->of_offset = of_offset;
+	dev->parent = parent;
+	dev->driver = drv;
+	dev->uclass = uc;
+	if (!dev->platdata && drv->platdata_auto_alloc_size)
+		dev->flags |= DM_FLAG_ALLOC_PDATA;
+
+	/* put dev into parent's successor list */
+	if (parent)
+		list_add_tail(&dev->sibling_node, &parent->child_head);
+
+	ret = uclass_bind_device(dev);
+	if (ret)
+		goto fail_bind;
+
+	/* if we fail to bind we remove device from successors and free it */
+	if (drv->bind) {
+		ret = drv->bind(dev);
+		if (ret) {
+			if (uclass_unbind_device(dev)) {
+				dm_warn("Failed to unbind dev '%s' on error path\n",
+					dev->name);
+			}
+			goto fail_bind;
+		}
+	}
+	if (parent)
+		dm_dbg("Bound device %s to %s\n", dev->name, parent->name);
+	*devp = dev;
+
+	return 0;
+
+fail_bind:
+	list_del(&dev->sibling_node);
+	free(dev);
+	return ret;
+}
+
+int device_bind_by_name(struct device *parent, const struct driver_info *info,
+			struct device **devp)
+{
+	struct driver *drv;
+
+	drv = lists_driver_lookup_name(info->name);
+	if (!drv)
+		return -ENOENT;
+
+	return device_bind(parent, drv, info->name, (void *)info->platdata,
+			   -1, devp);
+}
+
+int device_unbind(struct device *dev)
+{
+	struct driver *drv;
+	int ret;
+
+	if (!dev)
+		return -EINVAL;
+
+	if (dev->flags & DM_FLAG_ACTIVATED)
+		return -EINVAL;
+
+	drv = dev->driver;
+	assert(drv);
+
+	if (drv->unbind) {
+		ret = drv->unbind(dev);
+		if (ret)
+			return ret;
+	}
+
+	ret = device_chld_unbind(dev);
+	if (ret)
+		return ret;
+
+	ret = uclass_unbind_device(dev);
+	if (ret)
+		return ret;
+
+	if (dev->parent)
+		list_del(&dev->sibling_node);
+	free(dev);
+
+	return 0;
+}
+
+/**
+ * device_free() - Free memory buffers allocated by a device
+ * @dev:	Device that is to be started
+ */
+static void device_free(struct device *dev)
+{
+	int size;
+
+	if (dev->driver->priv_auto_alloc_size) {
+		free(dev->priv);
+		dev->priv = NULL;
+	}
+	if (dev->flags & DM_FLAG_ALLOC_PDATA) {
+		free(dev->platdata);
+		dev->platdata = NULL;
+	}
+	size = dev->uclass->uc_drv->per_device_auto_alloc_size;
+	if (size) {
+		free(dev->uclass_priv);
+		dev->uclass_priv = NULL;
+	}
+}
+
+int device_probe(struct device *dev)
+{
+	struct driver *drv;
+	int size = 0;
+	int ret;
+
+	if (!dev)
+		return -EINVAL;
+
+	if (dev->flags & DM_FLAG_ACTIVATED)
+		return 0;
+
+	drv = dev->driver;
+	assert(drv);
+
+	/* Allocate private data and platdata if requested */
+	if (drv->priv_auto_alloc_size) {
+		dev->priv = calloc(1, drv->priv_auto_alloc_size);
+		if (!dev->priv) {
+			ret = -ENOMEM;
+			goto fail;
+		}
+	}
+	/* Allocate private data if requested */
+	if (dev->flags & DM_FLAG_ALLOC_PDATA) {
+		dev->platdata = calloc(1, drv->platdata_auto_alloc_size);
+		if (!dev->platdata) {
+			ret = -ENOMEM;
+			goto fail;
+		}
+	}
+	size = dev->uclass->uc_drv->per_device_auto_alloc_size;
+	if (size) {
+		dev->uclass_priv = calloc(1, size);
+		if (!dev->uclass_priv) {
+			ret = -ENOMEM;
+			goto fail;
+		}
+	}
+
+	/* Ensure all parents are probed */
+	if (dev->parent) {
+		ret = device_probe(dev->parent);
+		if (ret)
+			goto fail;
+	}
+
+	if (drv->ofdata_to_platdata && dev->of_offset >= 0) {
+		ret = drv->ofdata_to_platdata(dev);
+		if (ret)
+			goto fail;
+	}
+
+	if (drv->probe) {
+		ret = drv->probe(dev);
+		if (ret)
+			goto fail;
+	}
+
+	dev->flags |= DM_FLAG_ACTIVATED;
+
+	ret = uclass_post_probe_device(dev);
+	if (ret) {
+		dev->flags &= ~DM_FLAG_ACTIVATED;
+		goto fail_uclass;
+	}
+
+	return 0;
+fail_uclass:
+	if (device_remove(dev)) {
+		dm_warn("%s: Device '%s' failed to remove on error path\n",
+			__func__, dev->name);
+	}
+fail:
+	device_free(dev);
+
+	return ret;
+}
+
+int device_remove(struct device *dev)
+{
+	struct driver *drv;
+	int ret;
+
+	if (!dev)
+		return -EINVAL;
+
+	if (!(dev->flags & DM_FLAG_ACTIVATED))
+		return 0;
+
+	drv = dev->driver;
+	assert(drv);
+
+	ret = uclass_pre_remove_device(dev);
+	if (ret)
+		return ret;
+
+	ret = device_chld_remove(dev);
+	if (ret)
+		goto err;
+
+	if (drv->remove) {
+		ret = drv->remove(dev);
+		if (ret)
+			goto err_remove;
+	}
+
+	device_free(dev);
+
+	dev->flags &= ~DM_FLAG_ACTIVATED;
+
+	return 0;
+
+err_remove:
+	/* We can't put the children back */
+	dm_warn("%s: Device '%s' failed to remove, but children are gone\n",
+		__func__, dev->name);
+err:
+	ret = uclass_post_probe_device(dev);
+	if (ret) {
+		dm_warn("%s: Device '%s' failed to post_probe on error path\n",
+			__func__, dev->name);
+	}
+
+	return ret;
+}
+
+void *dev_get_platdata(struct device *dev)
+{
+	if (!dev) {
+		dm_warn("%s: null device", __func__);
+		return NULL;
+	}
+
+	return dev->platdata;
+}
+
+void *dev_get_priv(struct device *dev)
+{
+	if (!dev) {
+		dm_warn("%s: null device", __func__);
+		return NULL;
+	}
+
+	return dev->priv;
+}
diff --git a/drivers/core/lists.c b/drivers/core/lists.c
new file mode 100644
index 0000000..4f2c126
--- /dev/null
+++ b/drivers/core/lists.c
@@ -0,0 +1,155 @@ 
+/*
+ * Copyright (c) 2013 Google, Inc
+ *
+ * (C) Copyright 2012
+ * Marek Vasut <marex@denx.de>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <dm/device.h>
+#include <dm/device-internal.h>
+#include <dm/platdata.h>
+#include <dm/uclass.h>
+#include <dm/util.h>
+#include <linux/compiler.h>
+
+struct driver *lists_driver_lookup_name(const char *name)
+{
+	struct driver *drv =
+		ll_entry_start(struct driver, driver);
+	const int n_ents = ll_entry_count(struct driver, driver);
+	struct driver *entry;
+	int len;
+
+	if (!drv || !n_ents)
+		return NULL;
+
+	len = strlen(name);
+
+	for (entry = drv; entry != drv + n_ents; entry++) {
+		if (strncmp(name, entry->name, len))
+			continue;
+
+		/* Full match */
+		if (len == strlen(entry->name))
+			return entry;
+	}
+
+	/* Not found */
+	return NULL;
+}
+
+struct uclass_driver *lists_uclass_lookup(enum uclass_id id)
+{
+	struct uclass_driver *uclass =
+		ll_entry_start(struct uclass_driver, uclass);
+	const int n_ents = ll_entry_count(struct uclass_driver, uclass);
+	struct uclass_driver *entry;
+
+	if ((id == UCLASS_INVALID) || !uclass)
+		return NULL;
+
+	for (entry = uclass; entry != uclass + n_ents; entry++) {
+		if (entry->id == id)
+			return entry;
+	}
+
+	return NULL;
+}
+
+int lists_bind_drivers(struct device *parent)
+{
+	struct driver_info *info =
+		ll_entry_start(struct driver_info, driver_info);
+	const int n_ents = ll_entry_count(struct driver_info, driver_info);
+	struct driver_info *entry;
+	struct device *dev;
+	int result = 0;
+	int ret;
+
+	for (entry = info; entry != info + n_ents; entry++) {
+		ret = device_bind_by_name(parent, entry, &dev);
+		if (ret) {
+			dm_warn("No match for driver '%s'\n", entry->name);
+			if (!result || ret != -ENOENT)
+				result = ret;
+		}
+	}
+
+	return result;
+}
+
+#ifdef CONFIG_OF_CONTROL
+/**
+ * driver_check_compatible() - Check if a driver is compatible with this node
+ *
+ * @param blob:		Device tree pointer
+ * @param offset:	Offset of node in device tree
+ * @param of_matchL	List of compatible strings to match
+ * @return 0 if there is a match, -ENOENT if no match, -ENODEV if the node
+ * does not have a compatible string, other error <0 if there is a device
+ * tree error
+ */
+static int driver_check_compatible(const void *blob, int offset,
+				   const struct device_id *of_match)
+{
+	int ret;
+
+	if (!of_match)
+		return -ENOENT;
+
+	while (of_match->compatible) {
+		ret = fdt_node_check_compatible(blob, offset,
+						of_match->compatible);
+		if (!ret)
+			return 0;
+		else if (ret == -FDT_ERR_NOTFOUND)
+			return -ENODEV;
+		else if (ret < 0)
+			return -EINVAL;
+		of_match++;
+	}
+
+	return -ENOENT;
+}
+
+int lists_bind_fdt(struct device *parent, const void *blob, int offset)
+{
+	struct driver *driver = ll_entry_start(struct driver, driver);
+	const int n_ents = ll_entry_count(struct driver, driver);
+	struct driver *entry;
+	struct device *dev;
+	const char *name;
+	int result = 0;
+	int ret;
+
+	dm_dbg("bind node %s\n", fdt_get_name(blob, offset, NULL));
+	for (entry = driver; entry != driver + n_ents; entry++) {
+		ret = driver_check_compatible(blob, offset, entry->of_match);
+		if (ret == -ENOENT) {
+			continue;
+		} else if (ret == -ENODEV) {
+			break;
+		} else if (ret) {
+			dm_warn("Device tree error at offset %d\n", offset);
+			if (!result || ret != -ENOENT)
+				result = ret;
+			break;
+		}
+
+		name = fdt_get_name(blob, offset, NULL);
+		dm_dbg("   - found match at '%s'\n", entry->name);
+		ret = device_bind(parent, entry, name, NULL, offset, &dev);
+		if (ret) {
+			dm_warn("No match for driver '%s'\n", entry->name);
+			if (!result || ret != -ENOENT)
+				result = ret;
+		}
+	}
+
+	return result;
+}
+#endif
diff --git a/drivers/core/root.c b/drivers/core/root.c
new file mode 100644
index 0000000..407bc0d
--- /dev/null
+++ b/drivers/core/root.c
@@ -0,0 +1,102 @@ 
+/*
+ * Copyright (c) 2013 Google, Inc
+ *
+ * (C) Copyright 2012
+ * Pavel Herrmann <morpheus.ibis@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <malloc.h>
+#include <dm/device.h>
+#include <dm/device-internal.h>
+#include <dm/lists.h>
+#include <dm/platdata.h>
+#include <dm/uclass.h>
+#include <dm/util.h>
+#include <linux/list.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static const struct driver_info root_info = {
+	.name		= "root_driver",
+};
+
+struct device *dm_root(void)
+{
+	if (!gd->dm_root) {
+		dm_warn("Virtual root driver does not exist!\n");
+		return NULL;
+	}
+
+	return gd->dm_root;
+}
+
+int dm_init(void)
+{
+	int ret;
+
+	if (gd->dm_root) {
+		dm_warn("Virtual root driver already exists!\n");
+		return -EINVAL;
+	}
+	INIT_LIST_HEAD(&gd->uclass_root);
+
+	ret = device_bind_by_name(NULL, &root_info, &gd->dm_root);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+int dm_scan_platdata(void)
+{
+	int ret;
+
+	ret = lists_bind_drivers(gd->dm_root);
+	if (ret == -ENOENT) {
+		dm_warn("Some drivers were not found\n");
+		ret = 0;
+	}
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+#ifdef CONFIG_OF_CONTROL
+int dm_scan_fdt(const void *blob)
+{
+	int offset = 0;
+	int ret = 0, err;
+	int depth = 0;
+
+	do {
+		offset = fdt_next_node(blob, offset, &depth);
+		if (offset > 0 && depth == 1) {
+			err = lists_bind_fdt(gd->dm_root, blob, offset);
+			if (err && !ret)
+				ret = err;
+		}
+	} while (offset > 0);
+
+	if (ret)
+		dm_warn("Some drivers failed to bind\n");
+
+	return ret;
+}
+#endif
+
+/* This is the root driver - all drivers are children of this */
+U_BOOT_DRIVER(root_driver) = {
+	.name	= "root_driver",
+	.id	= UCLASS_ROOT,
+};
+
+/* This is the root uclass */
+UCLASS_DRIVER(root) = {
+	.name	= "root",
+	.id	= UCLASS_ROOT,
+};
diff --git a/drivers/core/uclass.c b/drivers/core/uclass.c
new file mode 100644
index 0000000..4df5a8b
--- /dev/null
+++ b/drivers/core/uclass.c
@@ -0,0 +1,285 @@ 
+/*
+ * Copyright (c) 2013 Google, Inc
+ *
+ * (C) Copyright 2012
+ * Pavel Herrmann <morpheus.ibis@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <malloc.h>
+#include <dm/device.h>
+#include <dm/device-internal.h>
+#include <dm/lists.h>
+#include <dm/uclass.h>
+#include <dm/uclass-internal.h>
+#include <dm/util.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct uclass *uclass_find(enum uclass_id key)
+{
+	struct uclass *uc;
+
+	/*
+	 * TODO(sjg@chromium.org): Optimise this, perhaps moving the found
+	 * node to the start of the list, or creating a linear array mapping
+	 * id to node.
+	 */
+	list_for_each_entry(uc, &gd->uclass_root, sibling_node) {
+		if (uc->uc_drv->id == key)
+			return uc;
+	}
+
+	return NULL;
+}
+
+/**
+ * uclass_add() - Create new uclass in list
+ * @id: Id number to create
+ * @ucp: Returns pointer to uclass, or NULL on error
+ * @return 0 on success, -ve on error
+ *
+ * The new uclass is added to the list. There must be only one uclass for
+ * each id.
+ */
+static int uclass_add(enum uclass_id id, struct uclass **ucp)
+{
+	struct uclass_driver *uc_drv;
+	struct uclass *uc;
+	int ret;
+
+	*ucp = NULL;
+	uc_drv = lists_uclass_lookup(id);
+	if (!uc_drv) {
+		dm_warn("Cannot find uclass for id %d: please add the UCLASS_DRIVER() declaration for this UCLASS_... id\n",
+			id);
+		return -ENOENT;
+	}
+	if (uc_drv->ops) {
+		dm_warn("No ops for uclass id %d\n", id);
+		return -EINVAL;
+	}
+	uc = calloc(1, sizeof(*uc));
+	if (!uc)
+		return -ENOMEM;
+	if (uc_drv->priv_auto_alloc_size) {
+		uc->priv = calloc(1, uc_drv->priv_auto_alloc_size);
+		if (!uc->priv) {
+			ret = -ENOMEM;
+			goto fail_mem;
+		}
+	}
+	uc->uc_drv = uc_drv;
+	INIT_LIST_HEAD(&uc->sibling_node);
+	INIT_LIST_HEAD(&uc->dev_head);
+	list_add(&uc->sibling_node, &gd->uclass_root);
+
+	if (uc_drv->init) {
+		ret = uc_drv->init(uc);
+		if (ret)
+			goto fail;
+	}
+
+	*ucp = uc;
+
+	return 0;
+fail:
+	if (uc_drv->priv_auto_alloc_size) {
+		free(uc->priv);
+		uc->priv = NULL;
+	}
+	list_del(&uc->sibling_node);
+fail_mem:
+	free(uc);
+
+	return ret;
+}
+
+int uclass_destroy(struct uclass *uc)
+{
+	struct uclass_driver *uc_drv;
+	struct device *dev, *tmp;
+	int ret;
+
+	list_for_each_entry_safe(dev, tmp, &uc->dev_head, uclass_node) {
+		ret = device_remove(dev);
+		if (ret)
+			return ret;
+		ret = device_unbind(dev);
+		if (ret)
+			return ret;
+	}
+
+	uc_drv = uc->uc_drv;
+	if (uc_drv->destroy)
+		uc_drv->destroy(uc);
+	list_del(&uc->sibling_node);
+	if (uc_drv->priv_auto_alloc_size)
+		free(uc->priv);
+	free(uc);
+
+	return 0;
+}
+
+int uclass_get(enum uclass_id id, struct uclass **ucp)
+{
+	struct uclass *uc;
+
+	*ucp = NULL;
+	uc = uclass_find(id);
+	if (!uc)
+		return uclass_add(id, ucp);
+	*ucp = uc;
+
+	return 0;
+}
+
+int uclass_find_device(enum uclass_id id, int index, struct device **devp)
+{
+	struct uclass *uc;
+	struct device *dev;
+	int ret;
+
+	*devp = NULL;
+	ret = uclass_get(id, &uc);
+	if (ret)
+		return ret;
+
+	list_for_each_entry(dev, &uc->dev_head, uclass_node) {
+		if (!index--) {
+			*devp = dev;
+			return 0;
+		}
+	}
+
+	return -ENODEV;
+}
+
+int uclass_get_device(enum uclass_id id, int index, struct device **devp)
+{
+	struct device *dev;
+	int ret;
+
+	*devp = NULL;
+	ret = uclass_find_device(id, index, &dev);
+	if (ret)
+		return ret;
+
+	ret = device_probe(dev);
+	if (ret)
+		return ret;
+
+	*devp = dev;
+
+	return 0;
+}
+
+int uclass_first_device(enum uclass_id id, struct device **devp)
+{
+	struct uclass *uc;
+	struct device *dev;
+	int ret;
+
+	*devp = NULL;
+	ret = uclass_get(id, &uc);
+	if (ret)
+		return ret;
+	if (list_empty(&uc->dev_head))
+		return 0;
+
+	dev = list_first_entry(&uc->dev_head, struct device, uclass_node);
+	ret = device_probe(dev);
+	if (ret)
+		return ret;
+	*devp = dev;
+
+	return 0;
+}
+
+int uclass_next_device(struct device **devp)
+{
+	struct device *dev = *devp;
+	int ret;
+
+	*devp = NULL;
+	if (list_is_last(&dev->uclass_node, &dev->uclass->dev_head))
+		return 0;
+
+	dev = list_entry(dev->uclass_node.next, struct device, uclass_node);
+	ret = device_probe(dev);
+	if (ret)
+		return ret;
+	*devp = dev;
+
+	return 0;
+}
+
+int uclass_bind_device(struct device *dev)
+{
+	struct uclass *uc;
+	int ret;
+
+	uc = dev->uclass;
+
+	list_add_tail(&dev->uclass_node, &uc->dev_head);
+
+	if (uc->uc_drv->post_bind) {
+		ret = uc->uc_drv->post_bind(dev);
+		if (ret) {
+			list_del(&dev->uclass_node);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+int uclass_unbind_device(struct device *dev)
+{
+	struct uclass *uc;
+	int ret;
+
+	uc = dev->uclass;
+	if (uc->uc_drv->pre_unbind) {
+		ret = uc->uc_drv->pre_unbind(dev);
+		if (ret)
+			return ret;
+	}
+
+	list_del(&dev->uclass_node);
+	return 0;
+}
+
+int uclass_post_probe_device(struct device *dev)
+{
+	struct uclass_driver *uc_drv = dev->uclass->uc_drv;
+
+	if (uc_drv->post_probe)
+		return uc_drv->post_probe(dev);
+
+	return 0;
+}
+
+int uclass_pre_remove_device(struct device *dev)
+{
+	struct uclass_driver *uc_drv;
+	struct uclass *uc;
+	int ret;
+
+	uc = dev->uclass;
+	uc_drv = uc->uc_drv;
+	if (uc->uc_drv->pre_remove) {
+		ret = uc->uc_drv->pre_remove(dev);
+		if (ret)
+			return ret;
+	}
+	if (uc_drv->per_device_auto_alloc_size) {
+		free(dev->uclass_priv);
+		dev->uclass_priv = NULL;
+	}
+
+	return 0;
+}
diff --git a/drivers/core/util.c b/drivers/core/util.c
new file mode 100644
index 0000000..e01dd06
--- /dev/null
+++ b/drivers/core/util.c
@@ -0,0 +1,37 @@ 
+/*
+ * Copyright (c) 2013 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <vsprintf.h>
+
+void dm_warn(const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	vprintf(fmt, args);
+	va_end(args);
+}
+
+void dm_dbg(const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	vprintf(fmt, args);
+	va_end(args);
+}
+
+int list_count_items(struct list_head *head)
+{
+	struct list_head *node;
+	int count = 0;
+
+	list_for_each(node, head)
+		count++;
+
+	return count;
+}
diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
index 0de0bea..707400e 100644
--- a/include/asm-generic/global_data.h
+++ b/include/asm-generic/global_data.h
@@ -21,6 +21,8 @@ 
  */
 
 #ifndef __ASSEMBLY__
+#include <linux/list.h>
+
 typedef struct global_data {
 	bd_t *bd;
 	unsigned long flags;
@@ -61,6 +63,12 @@  typedef struct global_data {
 	unsigned long start_addr_sp;	/* start_addr_stackpointer */
 	unsigned long reloc_off;
 	struct global_data *new_gd;	/* relocated global data */
+
+#ifdef CONFIG_DM
+	struct device	*dm_root;	/* Root instance for Driver Model */
+	struct list_head uclass_root;	/* Head of core tree */
+#endif
+
 	const void *fdt_blob;	/* Our device tree, NULL if none */
 	void *new_fdt;		/* Relocated FDT */
 	unsigned long fdt_size;	/* Space reserved for relocated FDT */
diff --git a/include/dm.h b/include/dm.h
new file mode 100644
index 0000000..8bbb21b
--- /dev/null
+++ b/include/dm.h
@@ -0,0 +1,14 @@ 
+/*
+ * Copyright (c) 2013 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _DM_H_
+#define _DM_H
+
+#include <dm/device.h>
+#include <dm/platdata.h>
+#include <dm/uclass.h>
+
+#endif
diff --git a/include/dm/device-internal.h b/include/dm/device-internal.h
new file mode 100644
index 0000000..c026e8e
--- /dev/null
+++ b/include/dm/device-internal.h
@@ -0,0 +1,87 @@ 
+/*
+ * Copyright (C) 2013 Google, Inc
+ *
+ * (C) Copyright 2012
+ * Pavel Herrmann <morpheus.ibis@gmail.com>
+ * Marek Vasut <marex@denx.de>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _DM_DEVICE_INTERNAL_H
+#define _DM_DEVICE_INTERNAL_H
+
+struct device;
+
+/**
+ * device_bind() - Create a device and bind it to a driver
+ *
+ * Called to set up a new device attached to a driver. The device will either
+ * have platdata, or a device tree node which can be used to create the
+ * platdata.
+ *
+ * Once bound a device exists but is not yet active until device_probe() is
+ * called.
+ *
+ * @parent: Pointer to device's parent, under which this driver will exist
+ * @drv: Device's driver
+ * @name: Name of device (e.g. device tree node name)
+ * @platdata: Pointer to data for this device - the structure is device-
+ * specific but may include the device's I/O address, etc.. This is NULL for
+ * devices which use device tree.
+ * @of_offset: Offset of device tree node for this device. This is -1 for
+ * devices which don't use device tree.
+ * @devp: Returns a pointer to the bound device
+ * @return 0 if OK, -ve on error
+ */
+int device_bind(struct device *parent, struct driver *drv,
+		const char *name, void *platdata, int of_offset,
+		struct device **devp);
+
+/**
+ * device_bind_by_name: Create a device and bind it to a driver
+ *
+ * This is a helper function used to bind devices which do not use device
+ * tree.
+ *
+ * @parent: Pointer to device's parent
+ * @info: Name and platdata for this device
+ * @devp: Returns a pointer to the bound device
+ * @return 0 if OK, -ve on error
+ */
+int device_bind_by_name(struct device *parent, const struct driver_info *info,
+			struct device **devp);
+
+/**
+ * device_probe() - Probe a device, activating it
+ *
+ * Activate a device so that it is ready for use. All its parents are probed
+ * first.
+ *
+ * @dev: Pointer to device to probe
+ * @return 0 if OK, -ve on error
+ */
+int device_probe(struct device *dev);
+
+/**
+ * device_remove() - Remove a device, de-activating it
+ *
+ * De-activate a device so that it is no longer ready for use. All its
+ * children are deactivated first.
+ *
+ * @dev: Pointer to device to remove
+ * @return 0 if OK, -ve on error (an error here is normally a very bad thing)
+ */
+int device_remove(struct device *dev);
+
+/**
+ * device_unbind() - Unbind a device, destroying it
+ *
+ * Unbind a device and remove all memory used by it
+ *
+ * @dev: Pointer to device to unbind
+ * @return 0 if OK, -ve on error
+ */
+int device_unbind(struct device *dev);
+
+#endif
diff --git a/include/dm/device.h b/include/dm/device.h
new file mode 100644
index 0000000..4cd38ed
--- /dev/null
+++ b/include/dm/device.h
@@ -0,0 +1,159 @@ 
+/*
+ * Copyright (c) 2013 Google, Inc
+ *
+ * (C) Copyright 2012
+ * Pavel Herrmann <morpheus.ibis@gmail.com>
+ * Marek Vasut <marex@denx.de>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _DM_DEVICE_H
+#define _DM_DEVICE_H
+
+#include <dm/uclass-id.h>
+#include <linker_lists.h>
+#include <linux/list.h>
+
+struct driver_info;
+
+/* Driver is active (probed). Cleared when it is removed */
+#define DM_FLAG_ACTIVATED	(1 << 0)
+
+/* DM is responsible for allocating and freeing platdata */
+#define DM_FLAG_ALLOC_PDATA	(2 << 0)
+
+/**
+ * struct device - An instance of a driver
+ *
+ * This holds information about a device, which is a driver bound to a
+ * particular port or peripheral (essentially a driver instance).
+ *
+ * A device will come into existence through a 'bind' call, either due to
+ * a U_BOOT_DEVICE() macro (in which case platdata is non-NULL) or a node
+ * in the device tree (in which case of_offset is >= 0). In the latter case
+ * we translate the device tree information into platdata in a function
+ * implemented by the driver ofdata_to_platdata method (called just before the
+ * probe method if the device has a device tree node.
+ *
+ * All three of platdata, priv and uclass_priv can be allocated by the
+ * driver, or you can use the auto_alloc_size members of struct driver and
+ * struct uclass_driver to have driver model do this automatically.
+ *
+ * @driver: The driver used by this device
+ * @name: Name of device, typically the FDT node name
+ * @platdata: Configuration data for this device
+ * @of_offset: Device tree node offset for this device (- for none)
+ * @parent: Parent of this device, or NULL for the top level device
+ * @priv: Private data for this device
+ * @uclass: Pointer to uclass for this device
+ * @uclass_priv: The uclass's private data for this device
+ * @uclass_node: Used by uclass to link its devices
+ * @child_head: List of children of this device
+ * @sibling_node: Next device in list of all devices
+ * @flags: Flags for this device DM_FLAG_...
+ */
+struct device {
+	struct driver *driver;
+	const char *name;
+	void *platdata;
+	int of_offset;
+	struct device *parent;
+	void *priv;
+	struct uclass *uclass;
+	void *uclass_priv;
+	struct list_head uclass_node;
+	struct list_head child_head;
+	struct list_head sibling_node;
+	uint32_t flags;
+};
+
+/* Returns the operations for a device */
+#define device_get_ops(dev)	(dev->driver->ops)
+
+/* Returns non-zero if the device is active (probed and not removed) */
+#define device_active(dev)	((dev)->flags & DM_FLAG_ACTIVATED)
+
+/**
+ * struct device_id - Lists the compatible strings supported by a driver
+ * @compatible: Compatible string
+ * @data: Data for this compatible string
+ */
+struct device_id {
+	const char *compatible;
+	ulong data;
+};
+
+/**
+ * struct driver - A driver for a feature or peripheral
+ *
+ * This holds methods for setting up a new device, and also removing it.
+ * The device needs information to set itself up - this is provided either
+ * by platdata or a device tree node (which we find by looking up
+ * matching compatible strings with of_match).
+ *
+ * Drivers all belong to a uclass, representing a class of devices of the
+ * same type. Common elements of the drivers can be implemented in the uclass,
+ * or the uclass can provide a consistent interface to the drivers within
+ * it.
+ *
+ * @name: Device name
+ * @id: Identiies the uclass we belong to
+ * @of_match: List of compatible strings to match, and any identifying data
+ * for each.
+ * @bind: Called to bind a device to its driver
+ * @probe: Called to probe a device, i.e. activate it
+ * @remove: Called to remove a device, i.e. de-activate it
+ * @unbind: Called to unbind a device from its driver
+ * @ofdata_to_platdata: Called before probe to decode device tree data
+ * @priv_auto_alloc_size: If non-zero this is the size of the private data
+ * to be allocated in the device's ->priv pointer. If zero, then the driver
+ * is responsible for allocating any data required.
+ * @platdata_auto_alloc_size: If non-zero this is the size of the
+ * platform data to be allocated in the device's ->platdata pointer.
+ * This is typically only useful for device-tree-aware drivers (those with
+ * an of_match), since drivers which use platdata will have the data
+ * provided in the U_BOOT_DEVICE() instantiation.
+ * ops: Driver-specific operations. This is typically a list of function
+ * pointers defined by the driver, to implement driver functions required by
+ * the uclass.
+ */
+struct driver {
+	char *name;
+	enum uclass_id id;
+	const struct device_id *of_match;
+	int (*bind)(struct device *dev);
+	int (*probe)(struct device *dev);
+	int (*remove)(struct device *dev);
+	int (*unbind)(struct device *dev);
+	int (*ofdata_to_platdata)(struct device *dev);
+	int priv_auto_alloc_size;
+	int platdata_auto_alloc_size;
+	const void *ops;	/* driver-specific operations */
+};
+
+/* Declare a new U-Boot driver */
+#define U_BOOT_DRIVER(__name)						\
+	ll_entry_declare(struct driver, __name, driver)
+
+/**
+ * dev_get_platdata() - Get the platform data for a device
+ *
+ * This checks that dev is not NULL, but no other checks for now
+ *
+ * @dev		Device to check
+ * @return platform data, or NULL if none
+ */
+void *dev_get_platdata(struct device *dev);
+
+/**
+ * dev_get_priv() - Get the private data for a device
+ *
+ * This checks that dev is not NULL, but no other checks for now
+ *
+ * @dev		Device to check
+ * @return private data, or NULL if none
+ */
+void *dev_get_priv(struct device *dev);
+
+#endif
diff --git a/include/dm/lists.h b/include/dm/lists.h
new file mode 100644
index 0000000..0d09f9a
--- /dev/null
+++ b/include/dm/lists.h
@@ -0,0 +1,39 @@ 
+/*
+ * Copyright (c) 2013 Google, Inc
+ *
+ * (C) Copyright 2012
+ * Pavel Herrmann <morpheus.ibis@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _DM_LISTS_H_
+#define _DM_LISTS_H_
+
+#include <dm/uclass-id.h>
+
+/**
+ * lists_driver_lookup_name() - Return u_boot_driver corresponding to name
+ *
+ * This function returns a pointer to a driver given its name. This is used
+ * for binding a driver given its name and platdata.
+ *
+ * @name: Name of driver to look up
+ * @return pointer to driver, or NULL if not found
+ */
+struct driver *lists_driver_lookup_name(const char *name);
+
+/**
+ * lists_uclass_lookup() - Return uclass_driver based on ID of the class
+ * id:		ID of the class
+ *
+ * This function returns the pointer to uclass_driver, which is the class's
+ * base structure based on the ID of the class. Returns NULL on error.
+ */
+struct uclass_driver *lists_uclass_lookup(enum uclass_id id);
+
+int lists_bind_drivers(struct device *parent);
+
+int lists_bind_fdt(struct device *parent, const void *blob, int offset);
+
+#endif
diff --git a/include/dm/platdata.h b/include/dm/platdata.h
new file mode 100644
index 0000000..0ef3353
--- /dev/null
+++ b/include/dm/platdata.h
@@ -0,0 +1,22 @@ 
+/*
+ * Copyright (c) 2013 Google, Inc
+ *
+ * (C) Copyright 2012
+ * Pavel Herrmann <morpheus.ibis@gmail.com>
+ * Marek Vasut <marex@denx.de>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _DM_PLATDATA_H
+#define _DM_PLATDATA_H
+
+struct driver_info {
+	const char	*name;
+	const void	*platdata;
+};
+
+#define U_BOOT_DEVICE(__name)						\
+	ll_entry_declare(struct driver_info, __name, driver_info)
+
+#endif
diff --git a/include/dm/root.h b/include/dm/root.h
new file mode 100644
index 0000000..0ebccda
--- /dev/null
+++ b/include/dm/root.h
@@ -0,0 +1,53 @@ 
+/*
+ * Copyright (c) 2013 Google, Inc
+ *
+ * (C) Copyright 2012
+ * Pavel Herrmann <morpheus.ibis@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _DM_ROOT_H_
+#define _DM_ROOT_H_
+
+struct device;
+
+/**
+ * dm_root() - Return pointer to the top of the driver tree
+ *
+ * This function returns pointer to the root node of the driver tree,
+ *
+ * @return pointer to root device, or NULL if not inited yet
+ */
+struct device *dm_root(void);
+
+/**
+ * dm_scan_platdata() - Scan all platform data and bind drivers
+ *
+ * This scans all available platdata and creates drivers for each
+ *
+ * @return 0 if OK, -ve on error
+ */
+int dm_scan_platdata(void);
+
+/**
+ * dm_scan_fdt() - Scan the device tree and bind drivers
+ *
+ * This scans the device tree and creates a driver for each node
+ *
+ * @blob: Pointer to device tree blob
+ * @return 0 if OK, -ve on error
+ */
+int dm_scan_fdt(const void *blob);
+
+/**
+ * dm_init() - Initialize Driver Model structures
+ *
+ * This function will initialize roots of driver tree and class tree.
+ * This needs to be called before anything uses the DM
+ *
+ * @return 0 if OK, -ve on error
+ */
+int dm_init(void);
+
+#endif
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
new file mode 100644
index 0000000..f0e691c
--- /dev/null
+++ b/include/dm/uclass-id.h
@@ -0,0 +1,28 @@ 
+/*
+ * Copyright (c) 2013 Google, Inc
+ *
+ * (C) Copyright 2012
+ * Pavel Herrmann <morpheus.ibis@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _DM_UCLASS_ID_H
+#define _DM_UCLASS_ID_H
+
+/* TODO(sjg@chromium.org): this could be compile-time generated */
+enum uclass_id {
+	/* These are used internally by driver model */
+	UCLASS_ROOT = 0,
+	UCLASS_DEMO,
+	UCLASS_TEST,
+	UCLASS_TEST_FDT,
+
+	/* U-Boot uclasses start here */
+	UCLASS_GPIO,
+
+	UCLASS_COUNT,
+	UCLASS_INVALID = -1,
+};
+
+#endif
diff --git a/include/dm/uclass-internal.h b/include/dm/uclass-internal.h
new file mode 100644
index 0000000..cc65d52
--- /dev/null
+++ b/include/dm/uclass-internal.h
@@ -0,0 +1,85 @@ 
+/*
+ * Copyright (c) 2013 Google, Inc
+ *
+ * (C) Copyright 2012
+ * Pavel Herrmann <morpheus.ibis@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _DM_UCLASS_INTERNAL_H
+#define _DM_UCLASS_INTERNAL_H
+
+/**
+ * uclass_find_device() - Return n-th child of uclass
+ * @id:		Id number of the uclass
+ * @index:	Position of the child in uclass's list
+ * #devp:	Returns pointer to device, or NULL on error
+ *
+ * The device is not prepared for use - this is an internal function
+ *
+ * @return the uclass pointer of a child at the given index or
+ * return NULL on error.
+ */
+int uclass_find_device(enum uclass_id id, int index, struct device **devp);
+
+/**
+ * uclass_bind_device() - Associate device with a uclass
+ *
+ * Connect the device into uclass's list of devices.
+ *
+ * @dev:	Pointer to the device
+ * #return 0 on success, -ve on error
+ */
+int uclass_bind_device(struct device *dev);
+
+/**
+ * uclass_unbind_device() - Deassociate device with a uclass
+ *
+ * Disconnect the device from uclass's list of devices.
+ *
+ * @dev:	Pointer to the device
+ * #return 0 on success, -ve on error
+ */
+int uclass_unbind_device(struct device *dev);
+
+/**
+ * uclass_post_probe_device() - Deal with a device that has just been probed
+ *
+ * Perform any post-processing of a probed device that is needed by the
+ * uclass.
+ *
+ * @dev:	Pointer to the device
+ * #return 0 on success, -ve on error
+ */
+int uclass_post_probe_device(struct device *dev);
+
+/**
+ * uclass_pre_remove_device() - Handle a device which is about to be removed
+ *
+ * Perform any pre-processing of a device that is about to be removed.
+ *
+ * @dev:	Pointer to the device
+ * #return 0 on success, -ve on error
+ */
+int uclass_pre_remove_device(struct device *dev);
+
+/**
+ * uclass_find() - Find uclass by its id
+ *
+ * @id:		Id to serach for
+ * @return pointer to uclass, or NULL if not found
+ */
+struct uclass *uclass_find(enum uclass_id key);
+
+/**
+ * uclass_destroy() - Destroy a uclass
+ *
+ * Destroy a uclass and all its devices
+ *
+ * @uc: uclass to destroy
+ * @return 0 on success, -ve on error
+ */
+int uclass_destroy(struct uclass *uc);
+
+#endif
diff --git a/include/dm/uclass.h b/include/dm/uclass.h
new file mode 100644
index 0000000..cd23cfe
--- /dev/null
+++ b/include/dm/uclass.h
@@ -0,0 +1,142 @@ 
+/*
+ * Copyright (c) 2013 Google, Inc
+ *
+ * (C) Copyright 2012
+ * Pavel Herrmann <morpheus.ibis@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _DM_UCLASS_H
+#define _DM_UCLASS_H
+
+#include <dm/uclass-id.h>
+#include <linux/list.h>
+
+/**
+ * struct uclass - a U-Boot drive class, collecting together similar drivers
+ *
+ * A uclass provides an interface to a particular function, which is
+ * implemented by one or more drivers. Every driver belongs to a uclass even
+ * if it is the only driver in that uclass. An example uclass is GPIO, which
+ * provides the ability to change read inputs, set and clear outputs, etc.
+ * There may be drivers for on-chip SoC GPIO banks, I2C GPIO expanders and
+ * PMIC IO lines, all made available in a unified way through the uclass.
+ *
+ * @priv: Private data for this uclass
+ * @uc_drv: The driver for the uclass itself, not to be confused with a
+ * 'struct driver'
+ * dev_head: List of devices in this uclass (devices are attached to their
+ * uclass when their bind method is called)
+ * @sibling_node: Next uclass in the linked list of uclasses
+ */
+struct uclass {
+	void *priv;
+	struct uclass_driver *uc_drv;
+	struct list_head dev_head;
+	struct list_head sibling_node;
+};
+
+struct device;
+
+/**
+ * struct uclass_driver - Driver for the uclass
+ *
+ * A uclass_driver provides a consistent interface to a set of related
+ * drivers.
+ *
+ * @name: Name of uclass driver
+ * @id: ID number of this uclass
+ * @post_bind: Called after a new device is bound to this uclass
+ * @pre_unbind: Called before a device is unbound from this uclass
+ * @post_probe: Called after a new device is probed
+ * @pre_remove: Called before a device is removed
+ * @init: Called to set up the uclass
+ * @destroy: Called to destroy the uclass
+ * @priv_auto_alloc_size: If non-zero this is the size of the private data
+ * to be allocated in the uclass's ->priv pointer. If zero, then the uclass
+ * driver is responsible for allocating any data required.
+ * @per_device_auto_alloc_size: Each device can hold private data owned
+ * by the uclass. If required this will be automatically allocated if this
+ * value is non-zero.
+ * @ops: Uclass operations, providing the consistent interface to devices
+ * within the uclass.
+ */
+struct uclass_driver {
+	const char *name;
+	enum uclass_id id;
+	int (*post_bind)(struct device *dev);
+	int (*pre_unbind)(struct device *dev);
+	int (*post_probe)(struct device *dev);
+	int (*pre_remove)(struct device *dev);
+	int (*init)(struct uclass *class);
+	int (*destroy)(struct uclass *class);
+	int priv_auto_alloc_size;
+	int per_device_auto_alloc_size;
+	const void *ops;
+};
+
+/* Declare a new uclass_driver */
+#define UCLASS_DRIVER(__name)						\
+	ll_entry_declare(struct uclass_driver, __name, uclass)
+
+/**
+ * uclass_get() - Get a uclass based on an ID, creating it if needed
+ *
+ * Every uclass is identified by an ID, a number from 0 to n-1 where n is
+ * the number of uclasses. This function allows looking up a uclass by its
+ * ID.
+ *
+ * @key: ID to look up
+ * @ucp: Returns pointer to uclass (there is only one per ID)
+ * @return 0 if OK, -ve on error
+ */
+int uclass_get(enum uclass_id key, struct uclass **ucp);
+
+/**
+ * uclass_get_device() - Get a uclass device based on an ID and index
+ *
+ * id: ID to look up
+ * @index: Device number within that uclass (0=first)
+ * @ucp: Returns pointer to uclass (there is only one per for each ID)
+ * @return 0 if OK, -ve on error
+ */
+int uclass_get_device(enum uclass_id id, int index, struct device **ucp);
+
+/**
+ * uclass_first_device() - Get the first device in a uclass
+ *
+ * @id: Uclass ID to look up
+ * @devp: Returns pointer to the first device in that uclass, or NULL if none
+ * @return 0 if OK (found or not found), -1 on error
+ */
+int uclass_first_device(enum uclass_id id, struct device **devp);
+
+/**
+ * uclass_next_device() - Get the next device in a uclass
+ *
+ * @devp: On entry, pointer to device to lookup. On exit, returns pointer
+ * to the next device in the same uclass, or NULL if none
+ * @return 0 if OK (found or not found), -1 on error
+ */
+int uclass_next_device(struct device **devp);
+
+/**
+ * uclass_foreach_dev() - Helper function to iteration through devices
+ *
+ * This creates a for() loop which works through the available devices in
+ * a uclass in order from start to end.
+ *
+ * @pos: struct device * to hold the current device. Set to NULL when there
+ * are no more devices.
+ * uc: uclass to scan
+ */
+#define uclass_foreach_dev(pos, uc)					\
+	for (pos = list_entry((&(uc)->dev_head)->next, typeof(*pos),	\
+			uclass_node);					\
+	     prefetch(pos->uclass_node.next),				\
+			&pos->uclass_node != (&(uc)->dev_head);		\
+	     pos = list_entry(pos->uclass_node.next, typeof(*pos),	\
+			uclass_node))
+
+#endif
diff --git a/include/dm/util.h b/include/dm/util.h
new file mode 100644
index 0000000..8be64a9
--- /dev/null
+++ b/include/dm/util.h
@@ -0,0 +1,29 @@ 
+/*
+ * Copyright (c) 2013 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __DM_UTIL_H
+
+void dm_warn(const char *fmt, ...);
+
+#ifdef DEBUG
+void dm_dbg(const char *fmt, ...);
+#else
+static inline void dm_dbg(const char *fmt, ...)
+{
+}
+#endif
+
+struct list_head;
+
+/**
+ * list_count_items() - Count number of items in a list
+ *
+ * @param head:		Head of list
+ * @return number of items, or 0 if empty
+ */
+int list_count_items(struct list_head *head);
+
+#endif