[PATCH 5/5] fpga-region: separate out common code from dt specific code

[Alan Tull]

FPGA region is a layer above the FPGA manager and FPGA bridge
frameworks.  Currently, FPGA region is dependent on device tree.
This commit separates the device tree specific code from the
common code, separating fpga-region.c into fpga-region.c,
of-fpga-region.c, and fpga-region.h.

Functons exported from fpga-region.c:
* fpga_region_register
* fpga_region_unregister
  Create/remove a FPGA region.  Caller will supply the region
  struct initialized with a pointer to a FPGA manager and
  a method to get the FPGA bridges.

* of_fpga_region_find
  Find a fpga region, given the node pointer

* fpga_region_alloc_image_info
* fpga_region_free_image_info
  Alloc/free fpga_image_info struct

* fpga_region_program_fpga
  Program an FPGA region

Signed-off-by: Alan Tull <atull@xxxxxxxxxx>
---
 drivers/fpga/Kconfig          |  12 +-
 drivers/fpga/Makefile         |   1 +
 drivers/fpga/fpga-region.c    | 475 +++++++-----------------------------------
 drivers/fpga/fpga-region.h    |  50 +++++
 drivers/fpga/of-fpga-region.c | 453 ++++++++++++++++++++++++++++++++++++++++
 include/linux/fpga/fpga-mgr.h |   6 +-
 6 files changed, 599 insertions(+), 398 deletions(-)
 create mode 100644 drivers/fpga/fpga-region.h
 create mode 100644 drivers/fpga/of-fpga-region.c

diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
index ce861a2..be9c23d 100644
--- a/drivers/fpga/Kconfig
+++ b/drivers/fpga/Kconfig
@@ -15,10 +15,18 @@ if FPGA
 
 config FPGA_REGION
 	tristate "FPGA Region"
-	depends on OF && FPGA_BRIDGE
+	depends on FPGA_BRIDGE
+	help
+	  FPGA Region common code.  A FPGA Region controls a FPGA Manager
+	  and the FPGA Bridges associated with either a reconfigurable
+	  region of an FPGA or a whole FPGA.
+
+config OF_FPGA_REGION
+	tristate "FPGA Region Device Tree Overlay Support"
+	depends on FPGA_REGION
 	help
 	  FPGA Regions allow loading FPGA images under control of
-	  the Device Tree.
+	  Device Tree Overlays.
 
 config FPGA_MGR_SOCFPGA
 	tristate "Altera SOCFPGA FPGA Manager"
diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
index 8df07bc..fb88fb0 100644
--- a/drivers/fpga/Makefile
+++ b/drivers/fpga/Makefile
@@ -17,3 +17,4 @@ obj-$(CONFIG_ALTERA_FREEZE_BRIDGE)	+= altera-freeze-bridge.o
 
 # High Level Interfaces
 obj-$(CONFIG_FPGA_REGION)		+= fpga-region.o
+obj-$(CONFIG_OF_FPGA_REGION)		+= of-fpga-region.o
diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c
index 815f178..c06f2f7 100644
--- a/drivers/fpga/fpga-region.c
+++ b/drivers/fpga/fpga-region.c
@@ -16,53 +16,64 @@
  * this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+/* todo: prevent programming if region has child regions or overlay applied */
+
 #include <linux/fpga/fpga-bridge.h>
 #include <linux/fpga/fpga-mgr.h>
 #include <linux/idr.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/module.h>
-#include <linux/of_platform.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
+#include "fpga-region.h"
 
-/**
- * struct fpga_region - FPGA Region structure
- * @dev: FPGA Region device
- * @mutex: enforces exclusive reference to region
- * @bridge_list: list of FPGA bridges specified in region
- * @info: fpga image specific information
- */
-struct fpga_region {
-	struct device dev;
-	struct mutex mutex; /* for exclusive reference to region */
-	struct list_head bridge_list;
+static DEFINE_IDA(fpga_region_ida);
+struct class *fpga_region_class;
+
+struct fpga_image_info *fpga_region_alloc_image_info(struct fpga_region *region)
+{
+	struct device *dev = &region->dev;
 	struct fpga_image_info *info;
-};
 
-#define to_fpga_region(d) container_of(d, struct fpga_region, dev)
+	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return ERR_PTR(-ENOMEM);
 
-static DEFINE_IDA(fpga_region_ida);
-static struct class *fpga_region_class;
+	return info;
+}
+EXPORT_SYMBOL_GPL(fpga_region_alloc_image_info);
 
-static const struct of_device_id fpga_region_of_match[] = {
-	{ .compatible = "fpga-region", },
-	{},
-};
-MODULE_DEVICE_TABLE(of, fpga_region_of_match);
+void fpga_region_free_image_info(struct fpga_region *region,
+				 struct fpga_image_info *info)
+{
+	struct device *dev = &region->dev;
+
+	if (!info)
+		return;
+
+	if (info->firmware_name)
+		devm_kfree(dev, info->firmware_name);
 
+	devm_kfree(dev, info);
+}
+EXPORT_SYMBOL_GPL(fpga_region_free_image_info);
+
+#if IS_ENABLED(CONFIG_OF_FPGA_REGION)
 static int fpga_region_of_node_match(struct device *dev, const void *data)
 {
 	return dev->of_node == data;
 }
 
 /**
- * fpga_region_find - find FPGA region
+ * of_fpga_region_find - find FPGA region
  * @np: device node of FPGA Region
+ *
  * Caller will need to put_device(&region->dev) when done.
+ *
  * Returns FPGA Region struct or NULL
  */
-static struct fpga_region *fpga_region_find(struct device_node *np)
+struct fpga_region *of_fpga_region_find(struct device_node *np)
 {
 	struct device *dev;
 
@@ -73,6 +84,9 @@ static struct fpga_region *fpga_region_find(struct device_node *np)
 
 	return to_fpga_region(dev);
 }
+EXPORT_SYMBOL_GPL(of_fpga_region_find);
+
+#endif /* CONFIG_OF_FPGA_REGION */
 
 /**
  * fpga_region_get - get an exclusive reference to a fpga region
@@ -94,9 +108,7 @@ static struct fpga_region *fpga_region_get(struct fpga_region *region)
 	}
 
 	get_device(dev);
-	of_node_get(dev->of_node);
 	if (!try_module_get(dev->parent->driver->owner)) {
-		of_node_put(dev->of_node);
 		put_device(dev);
 		mutex_unlock(&region->mutex);
 		return ERR_PTR(-ENODEV);
@@ -119,397 +131,103 @@ static void fpga_region_put(struct fpga_region *region)
 	dev_dbg(&region->dev, "put\n");
 
 	module_put(dev->parent->driver->owner);
-	of_node_put(dev->of_node);
 	put_device(dev);
 	mutex_unlock(&region->mutex);
 }
 
 /**
- * fpga_region_get_manager - get reference for FPGA manager
- * @region: FPGA region
- *
- * Get FPGA Manager from "fpga-mgr" property or from ancestor region.
- *
- * Caller should call fpga_mgr_put() when done with manager.
- *
- * Return: fpga manager struct or IS_ERR() condition containing error code.
- */
-static struct fpga_manager *fpga_region_get_manager(struct fpga_region *region)
-{
-	struct device *dev = &region->dev;
-	struct device_node *np = dev->of_node;
-	struct device_node  *mgr_node;
-	struct fpga_manager *mgr;
-
-	of_node_get(np);
-	while (np) {
-		if (of_device_is_compatible(np, "fpga-region")) {
-			mgr_node = of_parse_phandle(np, "fpga-mgr", 0);
-			if (mgr_node) {
-				mgr = of_fpga_mgr_get(mgr_node);
-				of_node_put(np);
-				return mgr;
-			}
-		}
-		np = of_get_next_parent(np);
-	}
-	of_node_put(np);
-
-	return ERR_PTR(-EINVAL);
-}
-
-/**
- * fpga_region_get_bridges - create a list of bridges
- * @region: FPGA region
- * @overlay: device node of the overlay
- *
- * Create a list of bridges including the parent bridge and the bridges
- * specified by "fpga-bridges" property.  Note that the
- * fpga_bridges_enable/disable/put functions are all fine with an empty list
- * if that happens.
- *
- * Caller should call fpga_bridges_put(&region->bridge_list) when
- * done with the bridges.
- *
- * Return 0 for success (even if there are no bridges specified)
- * or -EBUSY if any of the bridges are in use.
- */
-static int fpga_region_get_bridges(struct fpga_region *region,
-				   struct device_node *overlay)
-{
-	struct device *dev = &region->dev;
-	struct device_node *region_np = dev->of_node;
-	struct device_node *br, *np, *parent_br = NULL;
-	int i, ret;
-
-	/* If parent is a bridge, add to list */
-	ret = of_fpga_bridge_get_to_list(region_np->parent, region->info,
-					 &region->bridge_list);
-	if (ret == -EBUSY)
-		return ret;
-
-	if (!ret)
-		parent_br = region_np->parent;
-
-	/* If overlay has a list of bridges, use it. */
-	if (of_parse_phandle(overlay, "fpga-bridges", 0))
-		np = overlay;
-	else
-		np = region_np;
-
-	for (i = 0; ; i++) {
-		br = of_parse_phandle(np, "fpga-bridges", i);
-		if (!br)
-			break;
-
-		/* If parent bridge is in list, skip it. */
-		if (br == parent_br)
-			continue;
-
-		/* If node is a bridge, get it and add to list */
-		ret = of_fpga_bridge_get_to_list(br, region->info,
-						 &region->bridge_list);
-
-		/* If any of the bridges are in use, give up */
-		if (ret == -EBUSY) {
-			fpga_bridges_put(&region->bridge_list);
-			return -EBUSY;
-		}
-	}
-
-	return 0;
-}
-
-/**
  * fpga_region_program_fpga - program FPGA
  * @region: FPGA region
  * @overlay: device node of the overlay
  * Program an FPGA using information in the region's fpga image info.
  * Return 0 for success or negative error code.
  */
-static int fpga_region_program_fpga(struct fpga_region *region,
-				    struct device_node *overlay)
+int fpga_region_program_fpga(struct fpga_region *region,
+			     struct fpga_image_info *info)
 {
-	struct fpga_manager *mgr;
+	struct device *dev = &region->dev;
 	int ret;
 
-	region = fpga_region_get(region);
-	if (IS_ERR(region)) {
-		pr_err("failed to get fpga region\n");
+	if (region->info) {
+		dev_err(dev, "region already programmed\n");
 		return PTR_ERR(region);
 	}
 
-	mgr = fpga_region_get_manager(region);
-	if (IS_ERR(mgr)) {
-		pr_err("failed to get fpga region manager\n");
-		return PTR_ERR(mgr);
+	region = fpga_region_get(region);
+	if (IS_ERR(region)) {
+		dev_err(dev, "failed to get fpga region\n");
+		return PTR_ERR(region);
 	}
 
-	ret = fpga_mgr_lock(mgr);
-	if (ret) {
-		pr_err("FPGA manager is busy\n");
-		goto err_put_mgr;
+	ret = fpga_mgr_lock(region->mgr);
+	if (ret < 0) {
+		dev_err(dev, "fpga manager is busy\n");
+		goto err_put_region;
 	}
 
-	ret = fpga_region_get_bridges(region, overlay);
-	if (ret) {
-		pr_err("failed to get fpga region bridges\n");
-		goto err_unlock_mgr;
+	/*
+	 * In some cases, we already have a list of bridges in the
+	 * fpga region struct.  Or we don't have any bridges.
+	 */
+	if (region->get_bridges) {
+		ret = region->get_bridges(region, info);
+		if (ret) {
+			dev_err(dev, "failed to get fpga region bridges\n");
+			goto err_unlock_mgr;
+		}
 	}
 
 	ret = fpga_bridges_disable(&region->bridge_list);
 	if (ret) {
-		pr_err("failed to disable region bridges\n");
+		dev_err(dev, "failed to disable region bridges\n");
 		goto err_put_br;
 	}
 
-	ret = fpga_mgr_load(mgr, region->info);
+	ret = fpga_mgr_load(region->mgr, info);
 	if (ret) {
-		pr_err("failed to load fpga image\n");
+		dev_err(dev, "failed to load fpga image\n");
 		goto err_put_br;
 	}
 
 	ret = fpga_bridges_enable(&region->bridge_list);
 	if (ret) {
-		pr_err("failed to enable region bridges\n");
+		dev_err(dev, "failed to enable region bridges\n");
 		goto err_put_br;
 	}
 
-	fpga_mgr_unlock(mgr);
-	fpga_mgr_put(mgr);
+	region->info = info;
+
+	fpga_mgr_unlock(region->mgr);
 	fpga_region_put(region);
 
 	return 0;
 
 err_put_br:
-	fpga_bridges_put(&region->bridge_list);
+	if (region->get_bridges)
+		fpga_bridges_put(&region->bridge_list);
 err_unlock_mgr:
-	fpga_mgr_unlock(mgr);
-err_put_mgr:
-	fpga_mgr_put(mgr);
+	fpga_mgr_unlock(region->mgr);
+err_put_region:
 	fpga_region_put(region);
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(fpga_region_program_fpga);
 
-/**
- * child_regions_with_firmware
- * @overlay: device node of the overlay
- *
- * If the overlay adds child FPGA regions, they are not allowed to have
- * firmware-name property.
- *
- * Return 0 for OK or -EINVAL if child FPGA region adds firmware-name.
- */
-static int child_regions_with_firmware(struct device_node *overlay)
+int fpga_region_register(struct device *dev, struct fpga_region *region)
 {
-	struct device_node *child_region;
-	const char *child_firmware_name;
-	int ret = 0;
-
-	of_node_get(overlay);
-
-	child_region = of_find_matching_node(overlay, fpga_region_of_match);
-	while (child_region) {
-		if (!of_property_read_string(child_region, "firmware-name",
-					     &child_firmware_name)) {
-			ret = -EINVAL;
-			break;
-		}
-		child_region = of_find_matching_node(child_region,
-						     fpga_region_of_match);
-	}
-
-	of_node_put(child_region);
-
-	if (ret)
-		pr_err("firmware-name not allowed in child FPGA region: %s",
-		       child_region->full_name);
-
-	return ret;
-}
-
-/**
- * fpga_region_notify_pre_apply - pre-apply overlay notification
- *
- * @region: FPGA region that the overlay was applied to
- * @nd: overlay notification data
- *
- * Called after when an overlay targeted to a FPGA Region is about to be
- * applied.  Function will check the properties that will be added to the FPGA
- * region.  If the checks pass, it will program the FPGA.
- *
- * The checks are:
- * The overlay must add either firmware-name or external-fpga-config property
- * to the FPGA Region.
- *
- *   firmware-name        : program the FPGA
- *   external-fpga-config : FPGA is already programmed
- *
- * The overlay can add other FPGA regions, but child FPGA regions cannot have a
- * firmware-name property since those regions don't exist yet.
- *
- * If the overlay that breaks the rules, notifier returns an error and the
- * overlay is rejected before it goes into the main tree.
- *
- * Returns 0 for success or negative error code for failure.
- */
-static int fpga_region_notify_pre_apply(struct fpga_region *region,
-					struct of_overlay_notify_data *nd)
-{
-	struct fpga_image_info *info;
-	int ret;
-
-	info = devm_kzalloc(&region->dev, sizeof(*info), GFP_KERNEL);
-	if (!info)
-		return -ENOMEM;
-
-	region->info = info;
-
-	/* Reject overlay if child FPGA Regions have firmware-name property */
-	ret = child_regions_with_firmware(nd->overlay);
-	if (ret)
-		return ret;
-
-	/* Read FPGA region properties from the overlay */
-	if (of_property_read_bool(nd->overlay, "partial-fpga-config"))
-		info->flags |= FPGA_MGR_PARTIAL_RECONFIG;
-
-	if (of_property_read_bool(nd->overlay, "external-fpga-config"))
-		info->flags |= FPGA_MGR_EXTERNAL_CONFIG;
-
-	of_property_read_string(nd->overlay, "firmware-name",
-				&info->firmware_name);
-
-	of_property_read_u32(nd->overlay, "region-unfreeze-timeout-us",
-			     &info->enable_timeout_us);
-
-	of_property_read_u32(nd->overlay, "region-freeze-timeout-us",
-			     &info->disable_timeout_us);
-
-	/* If FPGA was externally programmed, don't specify firmware */
-	if ((info->flags & FPGA_MGR_EXTERNAL_CONFIG) && info->firmware_name) {
-		pr_err("error: specified firmware and external-fpga-config");
-		return -EINVAL;
-	}
-
-	/* FPGA is already configured externally.  We're done. */
-	if (info->flags & FPGA_MGR_EXTERNAL_CONFIG)
-		return 0;
-
-	/* If we got this far, we should be programming the FPGA */
-	if (!info->firmware_name) {
-		pr_err("should specify firmware-name or external-fpga-config\n");
-		return -EINVAL;
-	}
-
-	return fpga_region_program_fpga(region, nd->overlay);
-}
-
-/**
- * fpga_region_notify_post_remove - post-remove overlay notification
- *
- * @region: FPGA region that was targeted by the overlay that was removed
- * @nd: overlay notification data
- *
- * Called after an overlay has been removed if the overlay's target was a
- * FPGA region.
- */
-static void fpga_region_notify_post_remove(struct fpga_region *region,
-					   struct of_overlay_notify_data *nd)
-{
-	fpga_bridges_disable(&region->bridge_list);
-	fpga_bridges_put(&region->bridge_list);
-	devm_kfree(&region->dev, region->info);
-	region->info = NULL;
-}
-
-/**
- * of_fpga_region_notify - reconfig notifier for dynamic DT changes
- * @nb:		notifier block
- * @action:	notifier action
- * @arg:	reconfig data
- *
- * This notifier handles programming a FPGA when a "firmware-name" property is
- * added to a fpga-region.
- *
- * Returns NOTIFY_OK or error if FPGA programming fails.
- */
-static int of_fpga_region_notify(struct notifier_block *nb,
-				 unsigned long action, void *arg)
-{
-	struct of_overlay_notify_data *nd = arg;
-	struct fpga_region *region;
-	int ret;
-
-	switch (action) {
-	case OF_OVERLAY_PRE_APPLY:
-		pr_debug("%s OF_OVERLAY_PRE_APPLY\n", __func__);
-		break;
-	case OF_OVERLAY_POST_APPLY:
-		pr_debug("%s OF_OVERLAY_POST_APPLY\n", __func__);
-		return NOTIFY_OK;       /* not for us */
-	case OF_OVERLAY_PRE_REMOVE:
-		pr_debug("%s OF_OVERLAY_PRE_REMOVE\n", __func__);
-		return NOTIFY_OK;       /* not for us */
-	case OF_OVERLAY_POST_REMOVE:
-		pr_debug("%s OF_OVERLAY_POST_REMOVE\n", __func__);
-		break;
-	default:			/* should not happen */
-		return NOTIFY_OK;
-	}
-
-	region = fpga_region_find(nd->target);
-	if (!region)
-		return NOTIFY_OK;
-
-	ret = 0;
-	switch (action) {
-	case OF_OVERLAY_PRE_APPLY:
-		ret = fpga_region_notify_pre_apply(region, nd);
-		break;
-
-	case OF_OVERLAY_POST_REMOVE:
-		fpga_region_notify_post_remove(region, nd);
-		break;
-	}
-
-	put_device(&region->dev);
-
-	if (ret)
-		return notifier_from_errno(ret);
-
-	return NOTIFY_OK;
-}
-
-static struct notifier_block fpga_region_of_nb = {
-	.notifier_call = of_fpga_region_notify,
-};
-
-static int fpga_region_probe(struct platform_device *pdev)
-{
-	struct device *dev = &pdev->dev;
-	struct device_node *np = dev->of_node;
-	struct fpga_region *region;
 	int id, ret = 0;
 
-	region = kzalloc(sizeof(*region), GFP_KERNEL);
-	if (!region)
-		return -ENOMEM;
-
 	id = ida_simple_get(&fpga_region_ida, 0, 0, GFP_KERNEL);
-	if (id < 0) {
-		ret = id;
-		goto err_kfree;
-	}
+	if (id < 0)
+		return id;
 
 	mutex_init(&region->mutex);
 	INIT_LIST_HEAD(&region->bridge_list);
-
 	device_initialize(&region->dev);
 	region->dev.class = fpga_region_class;
 	region->dev.parent = dev;
-	region->dev.of_node = np;
+	region->dev.of_node = dev->of_node;
 	region->dev.id = id;
 	dev_set_drvdata(dev, region);
 
@@ -521,82 +239,49 @@ static int fpga_region_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_remove;
 
-	of_platform_populate(np, fpga_region_of_match, NULL, &region->dev);
-
 	dev_info(dev, "FPGA Region probed\n");
 
 	return 0;
 
 err_remove:
 	ida_simple_remove(&fpga_region_ida, id);
-err_kfree:
-	kfree(region);
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(fpga_region_register);
 
-static int fpga_region_remove(struct platform_device *pdev)
+int fpga_region_unregister(struct fpga_region *region)
 {
-	struct fpga_region *region = platform_get_drvdata(pdev);
-
 	device_unregister(&region->dev);
 
 	return 0;
 }
-
-static struct platform_driver fpga_region_driver = {
-	.probe = fpga_region_probe,
-	.remove = fpga_region_remove,
-	.driver = {
-		.name	= "fpga-region",
-		.of_match_table = of_match_ptr(fpga_region_of_match),
-	},
-};
+EXPORT_SYMBOL_GPL(fpga_region_unregister);
 
 static void fpga_region_dev_release(struct device *dev)
 {
 	struct fpga_region *region = to_fpga_region(dev);
 
 	ida_simple_remove(&fpga_region_ida, region->dev.id);
-	kfree(region);
 }
 
 /**
  * fpga_region_init - init function for fpga_region class
- * Creates the fpga_region class and registers a reconfig notifier.
+ * Creates the fpga_region class.
  */
 static int __init fpga_region_init(void)
 {
-	int ret;
-
 	fpga_region_class = class_create(THIS_MODULE, "fpga_region");
 	if (IS_ERR(fpga_region_class))
 		return PTR_ERR(fpga_region_class);
 
 	fpga_region_class->dev_release = fpga_region_dev_release;
 
-	ret = of_overlay_notifier_register(&fpga_region_of_nb);
-	if (ret)
-		goto err_class;
-
-	ret = platform_driver_register(&fpga_region_driver);
-	if (ret)
-		goto err_plat;
-
 	return 0;
-
-err_plat:
-	of_overlay_notifier_unregister(&fpga_region_of_nb);
-err_class:
-	class_destroy(fpga_region_class);
-	ida_destroy(&fpga_region_ida);
-	return ret;
 }
 
 static void __exit fpga_region_exit(void)
 {
-	platform_driver_unregister(&fpga_region_driver);
-	of_overlay_notifier_unregister(&fpga_region_of_nb);
 	class_destroy(fpga_region_class);
 	ida_destroy(&fpga_region_ida);
 }
diff --git a/drivers/fpga/fpga-region.h b/drivers/fpga/fpga-region.h
new file mode 100644
index 0000000..472f2f9
--- /dev/null
+++ b/drivers/fpga/fpga-region.h
@@ -0,0 +1,50 @@
+#include <linux/device.h>
+#include <linux/fpga/fpga-mgr.h>
+#include <linux/fpga/fpga-bridge.h>
+
+#ifndef _FPGA_REGION_H
+#define _FPGA_REGION_H
+
+/**
+ * struct fpga_region - FPGA Region structure
+ * @dev: FPGA Region device
+ * @mutex: enforces exclusive reference to region
+ * @bridge_list: list of FPGA bridges specified in region
+ * @overlays: list of struct region_overlay_info
+ * @mgr_dev: device of fpga manager
+ * @priv: private data
+ */
+struct fpga_region {
+	struct device dev;
+	struct mutex mutex; /* for exclusive reference to region */
+	struct list_head bridge_list;
+	struct fpga_manager *mgr;
+	struct fpga_image_info *info;
+	void *priv;
+	int (*get_bridges)(struct fpga_region *region,
+			   struct fpga_image_info *image_info);
+};
+
+#define to_fpga_region(d) container_of(d, struct fpga_region, dev)
+
+#ifdef CONFIG_OF
+struct fpga_region *of_fpga_region_find(struct device_node *np);
+#else
+struct fpga_region *of_fpga_region_find(struct device_node *np)
+{
+	return NULL;
+}
+#endif /* CONFIG_OF */
+
+struct fpga_image_info *fpga_region_alloc_image_info(
+				struct fpga_region *region);
+void fpga_region_free_image_info(struct fpga_region *region,
+				 struct fpga_image_info *image_info);
+
+int fpga_region_program_fpga(struct fpga_region *region,
+			     struct fpga_image_info *image_info);
+
+int fpga_region_register(struct device *dev, struct fpga_region *region);
+int fpga_region_unregister(struct fpga_region *region);
+
+#endif /* _FPGA_REGION_H */
diff --git a/drivers/fpga/of-fpga-region.c b/drivers/fpga/of-fpga-region.c
new file mode 100644
index 0000000..7809036
--- /dev/null
+++ b/drivers/fpga/of-fpga-region.c
@@ -0,0 +1,453 @@
+/*
+ * FPGA Region - Device Tree support for FPGA programming under Linux
+ *
+ *  Copyright (C) 2013-2016 Altera Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/fpga/fpga-bridge.h>
+#include <linux/fpga/fpga-mgr.h>
+#include <linux/idr.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include "fpga-region.h"
+
+/**
+ * of_fpga_region_get_manager - get pointer for FPGA Manager
+ * @dev: FPGA region's device
+ *
+ * Get FPGA Manager from "fpga-mgr" property in region or in ancestor region.
+ *
+ * Caller should call fpga_mgr_put() when done with manager.
+ *
+ * Return: fpga manager struct or IS_ERR() condition containing error code.
+ */
+static struct fpga_manager *of_fpga_region_get_mgr(struct device_node *np)
+{
+	struct device_node  *mgr_node;
+	struct fpga_manager *mgr;
+
+	of_node_get(np);
+	while (np) {
+		if (of_device_is_compatible(np, "fpga-region")) {
+			mgr_node = of_parse_phandle(np, "fpga-mgr", 0);
+			if (mgr_node) {
+				mgr = of_fpga_mgr_get(mgr_node);
+				of_node_put(np);
+				return mgr;
+			}
+		}
+		np = of_get_next_parent(np);
+	}
+	of_node_put(np);
+
+	return ERR_PTR(-EINVAL);
+}
+
+/**
+ * of_fpga_region_get_bridges - create a list of bridges
+ * @region: FPGA region
+ * @image_info: FPGA image info
+ *
+ * Create a list of bridges including the parent bridge and the bridges
+ * specified by "fpga-bridges" property.  Note that the
+ * fpga_bridges_enable/disable/put functions are all fine with an empty list
+ * if that happens.
+ *
+ * Caller should call fpga_bridges_put(&region->bridge_list) when
+ * done with the bridges.
+ *
+ * Return 0 for success (even if there are no bridges specified)
+ * or -EBUSY if any of the bridges are in use.
+ */
+static int of_fpga_region_get_bridges(struct fpga_region *region,
+				      struct fpga_image_info *image_info)
+{
+	struct device *dev = &region->dev;
+	struct device_node *region_np = dev->of_node;
+	struct device_node *br, *np, *parent_br = NULL;
+	int i, ret;
+
+	/* If parent is a bridge, add to list */
+	ret = of_fpga_bridge_get_to_list(region_np->parent,
+					 image_info,
+					 &region->bridge_list);
+	if (ret == -EBUSY)
+		return ret;
+
+	if (!ret)
+		parent_br = region_np->parent;
+
+	/* If overlay has a list of bridges, use it. */
+	if (of_parse_phandle(image_info->overlay, "fpga-bridges", 0))
+		np = image_info->overlay;
+	else
+		np = region_np;
+
+	for (i = 0; ; i++) {
+		br = of_parse_phandle(np, "fpga-bridges", i);
+		if (!br)
+			break;
+
+		/* If parent bridge is in list, skip it. */
+		if (br == parent_br)
+			continue;
+
+		/* If node is a bridge, get it and add to list */
+		ret = of_fpga_bridge_get_to_list(br, image_info,
+						 &region->bridge_list);
+
+		/* If any of the bridges are in use, give up */
+		if (ret == -EBUSY) {
+			fpga_bridges_put(&region->bridge_list);
+			return -EBUSY;
+		}
+	}
+
+	return 0;
+}
+
+static const struct of_device_id fpga_region_of_match[] = {
+	{ .compatible = "fpga-region", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, fpga_region_of_match);
+
+/**
+ * child_regions_with_firmware
+ * @overlay: device node of the overlay
+ *
+ * If the overlay adds child FPGA regions, they are not allowed to have
+ * firmware-name property.
+ *
+ * Return 0 for OK or -EINVAL if child FPGA region adds firmware-name.
+ */
+static int child_regions_with_firmware(struct device_node *overlay)
+{
+	struct device_node *child_region;
+	const char *child_firmware_name;
+	int ret = 0;
+
+	of_node_get(overlay);
+
+	child_region = of_find_matching_node(overlay, fpga_region_of_match);
+	while (child_region) {
+		if (!of_property_read_string(child_region, "firmware-name",
+					     &child_firmware_name)) {
+			ret = -EINVAL;
+			break;
+		}
+		child_region = of_find_matching_node(child_region,
+						     fpga_region_of_match);
+	}
+
+	of_node_put(child_region);
+
+	if (ret)
+		pr_err("firmware-name not allowed in child FPGA region: %s",
+		       child_region->full_name);
+
+	return ret;
+}
+
+/**
+ * of_fpga_region_parse_ov - parse and check overlay applied to region
+ *
+ * @region: FPGA region
+ * @overlay: overlay applied to the FPGA region
+ *
+ * Given an overlay applied to a FPGA region, parse the FPGA image specific
+ * info in the overlay and do some checking.
+ *
+ * Returns:
+ *   NULL if overlay doesn't direct us to program the FPGA.
+ *   fpga_image_info struct if there is an image to program.
+ *   error code for invalid overlay.
+ */
+static struct fpga_image_info *of_fpga_region_parse_ov(
+						struct fpga_region *region,
+						struct device_node *overlay)
+{
+	struct device *dev = &region->dev;
+	struct fpga_image_info *info;
+	const char *firmware_name;
+	int ret;
+
+	/*
+	 * Reject overlay if child FPGA Regions added in the overlay have
+	 * firmware-name property (would mean that an FPGA region that has
+	 * not been added to the live tree yet is doing FPGA programming).
+	 */
+	ret = child_regions_with_firmware(overlay);
+	if (ret)
+		return ERR_PTR(ret);
+
+	info = fpga_region_alloc_image_info(region);
+	if (!info)
+		return ERR_PTR(-ENOMEM);
+
+	info->overlay = overlay;
+
+	if (of_property_read_bool(overlay, "partial-fpga-config"))
+		info->flags |= FPGA_MGR_PARTIAL_RECONFIG;
+
+	if (of_property_read_bool(overlay, "external-fpga-config"))
+		info->flags |= FPGA_MGR_EXTERNAL_CONFIG;
+
+	if (!of_property_read_string(overlay, "firmware-name",
+				     &firmware_name)) {
+		info->firmware_name = devm_kstrdup(dev, firmware_name,
+						   GFP_KERNEL);
+		if (!info->firmware_name)
+			return ERR_PTR(-ENOMEM);
+	}
+
+	of_property_read_u32(overlay, "region-unfreeze-timeout-us",
+			     &info->enable_timeout_us);
+
+	of_property_read_u32(overlay, "region-freeze-timeout-us",
+			     &info->disable_timeout_us);
+
+	/* If overlay is not programming the FPGA, don't need FPGA image info */
+	if (!info->firmware_name) {
+		ret = 0;
+		goto ret_no_info;
+	}
+
+	/*
+	 * If overlay informs us FPGA was externally programmed, specifying
+	 * firmware here would be ambiguous.
+	 */
+	if (info->flags & FPGA_MGR_EXTERNAL_CONFIG) {
+		dev_err(dev, "error: specified firmware and external-fpga-config");
+		ret = -EINVAL;
+		goto ret_no_info;
+	}
+
+	return info;
+ret_no_info:
+	fpga_region_free_image_info(region, info);
+	return ERR_PTR(ret);
+}
+
+/**
+ * of_fpga_region_notify_pre_apply - pre-apply overlay notification
+ *
+ * @region: FPGA region that the overlay will be applied to
+ * @nd: overlay notification data
+ *
+ * Called when an overlay targeted to a FPGA Region is about to be applied.
+ * Parses the overlay for properties that influence how the FPGA will be
+ * programmed and does some checking. If the checks pass, programs the FPGA.
+ *
+ * If the overlay that breaks the rules, notifier returns an error and the
+ * overlay is rejected, preventing it from being added to the main tree.
+ *
+ * Return: 0 for success or negative error code for failure.
+ */
+static int of_fpga_region_notify_pre_apply(struct fpga_region *region,
+					   struct of_overlay_notify_data *nd)
+{
+	struct fpga_image_info *info;
+	int ret;
+
+	if (region->info) {
+		dev_err(&region->dev, "Region already has overlay applied.\n");
+		return -EINVAL;
+	}
+
+	info = of_fpga_region_parse_ov(region, nd->overlay);
+	if (IS_ERR(info))
+		return PTR_ERR(info);
+
+	if (info) {
+		ret = fpga_region_program_fpga(region, info);
+		if (ret)
+			goto pre_a_err;
+	}
+
+	return 0;
+
+pre_a_err:
+	fpga_region_free_image_info(region, info);
+	return ret;
+}
+
+/**
+ * of_fpga_region_notify_post_remove - post-remove overlay notification
+ *
+ * @region: FPGA region that was targeted by the overlay that was removed
+ * @nd: overlay notification data
+ *
+ * Called after an overlay has been removed if the overlay's target was a
+ * FPGA region.
+ */
+static void of_fpga_region_notify_post_remove(struct fpga_region *region,
+					      struct of_overlay_notify_data *nd)
+{
+	fpga_bridges_disable(&region->bridge_list);
+	fpga_bridges_put(&region->bridge_list);
+	fpga_region_free_image_info(region, region->info);
+	region->info = NULL;
+}
+
+/**
+ * of_fpga_region_notify - reconfig notifier for dynamic DT changes
+ * @nb:		notifier block
+ * @action:	notifier action
+ * @arg:	reconfig data
+ *
+ * This notifier handles programming a FPGA when a "firmware-name" property is
+ * added to a fpga-region.
+ *
+ * Returns NOTIFY_OK or error if FPGA programming fails.
+ */
+static int of_fpga_region_notify(struct notifier_block *nb,
+				 unsigned long action, void *arg)
+{
+	struct of_overlay_notify_data *nd = arg;
+	struct fpga_region *region;
+	int ret;
+
+	switch (action) {
+	case OF_OVERLAY_PRE_APPLY:
+		pr_debug("%s OF_OVERLAY_PRE_APPLY\n", __func__);
+		break;
+	case OF_OVERLAY_POST_APPLY:
+		pr_debug("%s OF_OVERLAY_POST_APPLY\n", __func__);
+		return NOTIFY_OK;       /* not for us */
+	case OF_OVERLAY_PRE_REMOVE:
+		pr_debug("%s OF_OVERLAY_PRE_REMOVE\n", __func__);
+		return NOTIFY_OK;       /* not for us */
+	case OF_OVERLAY_POST_REMOVE:
+		pr_debug("%s OF_OVERLAY_POST_REMOVE\n", __func__);
+		break;
+	default:			/* should not happen */
+		return NOTIFY_OK;
+	}
+
+	region = of_fpga_region_find(nd->target);
+	if (!region)
+		return NOTIFY_OK;
+
+	ret = 0;
+	switch (action) {
+	case OF_OVERLAY_PRE_APPLY:
+		ret = of_fpga_region_notify_pre_apply(region, nd);
+		break;
+
+	case OF_OVERLAY_POST_REMOVE:
+		of_fpga_region_notify_post_remove(region, nd);
+		break;
+	}
+
+	put_device(&region->dev);
+
+	if (ret)
+		return notifier_from_errno(ret);
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block fpga_region_of_nb = {
+	.notifier_call = of_fpga_region_notify,
+};
+
+static int of_fpga_region_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct fpga_manager *mgr;
+	struct fpga_region *region;
+	int ret;
+
+	region = devm_kzalloc(dev, sizeof(*region), GFP_KERNEL);
+	if (!region)
+		return -ENOMEM;
+
+	/* Find the FPGA mgr specified by region or parent region. */
+	mgr = of_fpga_region_get_mgr(np);
+	if (IS_ERR(mgr)) {
+		ret = PTR_ERR(mgr);
+		goto err_kfree;
+	}
+	region->mgr = mgr;
+
+	/* Specify how to get bridges for this type of region. */
+	region->get_bridges = of_fpga_region_get_bridges;
+
+	ret = fpga_region_register(dev, region);
+	if (ret)
+		goto err_put_mgr;
+
+	of_platform_populate(np, fpga_region_of_match, NULL, &region->dev);
+	dev_info(dev, "FPGA Region probed\n");
+
+	return ret;
+
+err_put_mgr:
+	fpga_mgr_put(mgr);
+err_kfree:
+	devm_kfree(dev, region);
+
+	return ret;
+}
+
+static int of_fpga_region_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct fpga_region *region = platform_get_drvdata(pdev);
+
+	fpga_region_unregister(region);
+	devm_kfree(dev, region);
+
+	return 0;
+}
+
+static struct platform_driver fpga_region_driver = {
+	.probe = of_fpga_region_probe,
+	.remove = of_fpga_region_remove,
+	.driver = {
+		.name	= "fpga-region",
+		.of_match_table = of_match_ptr(fpga_region_of_match),
+	},
+};
+
+static int __init of_fpga_region_notifier_init(void)
+{
+	int ret;
+
+	ret = platform_driver_register(&fpga_region_driver);
+	if (ret)
+		return ret;
+
+	return of_overlay_notifier_register(&fpga_region_of_nb);
+}
+
+static void __exit of_fpga_region_notifier_exit(void)
+{
+	of_overlay_notifier_unregister(&fpga_region_of_nb);
+	platform_driver_unregister(&fpga_region_driver);
+}
+
+device_initcall(of_fpga_region_notifier_init);
+module_exit(of_fpga_region_notifier_exit);
+
+MODULE_DESCRIPTION("OF FPGA Region");
+MODULE_AUTHOR("Alan Tull <atull@xxxxxxxxxxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/fpga/fpga-mgr.h b/include/linux/fpga/fpga-mgr.h
index ae970ca..0f5072c 100644
--- a/include/linux/fpga/fpga-mgr.h
+++ b/include/linux/fpga/fpga-mgr.h
@@ -80,15 +80,19 @@ enum fpga_mgr_states {
  * @sgt: scatter/gather table containing FPGA image
  * @buf: contiguous buffer containing FPGA image
  * @count: size of buf
+ * @overlay: Device Tree overlay
  */
 struct fpga_image_info {
 	u32 flags;
 	u32 enable_timeout_us;
 	u32 disable_timeout_us;
-	const char *firmware_name;
+	char *firmware_name;
 	struct sg_table *sgt;
 	const char *buf;
 	size_t count;
+#ifdef CONFIG_OF
+	struct device_node *overlay;
+#endif
 };
 
 /**
-- 
2.7.4