diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
new file mode 100644
index 0000000..a9b521b
--- /dev/null
+++ b/drivers/fpga/dfl.c
@@ -0,0 +1,1044 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for FPGA Device Feature List (DFL) Support
+ *
+ * Copyright (C) 2017-2018 Intel Corporation, Inc.
+ *
+ * Authors:
+ *   Kang Luwei <luwei.kang@intel.com>
+ *   Zhang Yi <yi.z.zhang@intel.com>
+ *   Wu Hao <hao.wu@intel.com>
+ *   Xiao Guangrong <guangrong.xiao@linux.intel.com>
+ */
+#include <linux/module.h>
+
+#include "dfl.h"
+
+static DEFINE_MUTEX(dfl_id_mutex);
+
+/*
+ * when adding a new feature dev support in DFL framework, it's required to
+ * add a new item in enum dfl_id_type and provide related information in below
+ * dfl_devs table which is indexed by dfl_id_type, e.g. name string used for
+ * platform device creation (define name strings in dfl.h, as they could be
+ * reused by platform device drivers).
+ *
+ * if the new feature dev needs chardev support, then it's required to add
+ * a new item in dfl_chardevs table and configure dfl_devs[i].devt_type as
+ * index to dfl_chardevs table. If no chardev support just set devt_type
+ * as one invalid index (DFL_FPGA_DEVT_MAX).
+ */
+enum dfl_id_type {
+	FME_ID,		/* fme id allocation and mapping */
+	PORT_ID,	/* port id allocation and mapping */
+	DFL_ID_MAX,
+};
+
+enum dfl_fpga_devt_type {
+	DFL_FPGA_DEVT_FME,
+	DFL_FPGA_DEVT_PORT,
+	DFL_FPGA_DEVT_MAX,
+};
+
+/**
+ * dfl_dev_info - dfl feature device information.
+ * @name: name string of the feature platform device.
+ * @dfh_id: id value in Device Feature Header (DFH) register by DFL spec.
+ * @id: idr id of the feature dev.
+ * @devt_type: index to dfl_chrdevs[].
+ */
+struct dfl_dev_info {
+	const char *name;
+	u32 dfh_id;
+	struct idr id;
+	enum dfl_fpga_devt_type devt_type;
+};
+
+/* it is indexed by dfl_id_type */
+static struct dfl_dev_info dfl_devs[] = {
+	{.name = DFL_FPGA_FEATURE_DEV_FME, .dfh_id = DFH_ID_FIU_FME,
+	 .devt_type = DFL_FPGA_DEVT_FME},
+	{.name = DFL_FPGA_FEATURE_DEV_PORT, .dfh_id = DFH_ID_FIU_PORT,
+	 .devt_type = DFL_FPGA_DEVT_PORT},
+};
+
+/**
+ * dfl_chardev_info - chardev information of dfl feature device
+ * @name: nmae string of the char device.
+ * @devt: devt of the char device.
+ */
+struct dfl_chardev_info {
+	const char *name;
+	dev_t devt;
+};
+
+/* indexed by enum dfl_fpga_devt_type */
+static struct dfl_chardev_info dfl_chrdevs[] = {
+	{.name = DFL_FPGA_FEATURE_DEV_FME},
+	{.name = DFL_FPGA_FEATURE_DEV_PORT},
+};
+
+static void dfl_ids_init(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(dfl_devs); i++)
+		idr_init(&dfl_devs[i].id);
+}
+
+static void dfl_ids_destroy(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(dfl_devs); i++)
+		idr_destroy(&dfl_devs[i].id);
+}
+
+static int dfl_id_alloc(enum dfl_id_type type, struct device *dev)
+{
+	int id;
+
+	WARN_ON(type >= DFL_ID_MAX);
+	mutex_lock(&dfl_id_mutex);
+	id = idr_alloc(&dfl_devs[type].id, dev, 0, 0, GFP_KERNEL);
+	mutex_unlock(&dfl_id_mutex);
+
+	return id;
+}
+
+static void dfl_id_free(enum dfl_id_type type, int id)
+{
+	WARN_ON(type >= DFL_ID_MAX);
+	mutex_lock(&dfl_id_mutex);
+	idr_remove(&dfl_devs[type].id, id);
+	mutex_unlock(&dfl_id_mutex);
+}
+
+static enum dfl_id_type feature_dev_id_type(struct platform_device *pdev)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(dfl_devs); i++)
+		if (!strcmp(dfl_devs[i].name, pdev->name))
+			return i;
+
+	return DFL_ID_MAX;
+}
+
+static enum dfl_id_type dfh_id_to_type(u32 id)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(dfl_devs); i++)
+		if (dfl_devs[i].dfh_id == id)
+			return i;
+
+	return DFL_ID_MAX;
+}
+
+/*
+ * introduce a global port_ops list, it allows port drivers to register ops
+ * in such list, then other feature devices (e.g. FME), could use the port
+ * functions even related port platform device is hidden. Below is one example,
+ * in virtualization case of PCIe-based FPGA DFL device, when SRIOV is
+ * enabled, port (and it's AFU) is turned into VF and port platform device
+ * is hidden from system but it's still required to access port to finish FPGA
+ * reconfiguration function in FME.
+ */
+
+static DEFINE_MUTEX(dfl_port_ops_mutex);
+static LIST_HEAD(dfl_port_ops_list);
+
+/**
+ * dfl_fpga_port_ops_get - get matched port ops from the global list
+ * @pdev: platform device to match with associated port ops.
+ * Return: matched port ops on success, NULL otherwise.
+ *
+ * Please note that must dfl_fpga_port_ops_put after use the port_ops.
+ */
+struct dfl_fpga_port_ops *dfl_fpga_port_ops_get(struct platform_device *pdev)
+{
+	struct dfl_fpga_port_ops *ops = NULL;
+
+	mutex_lock(&dfl_port_ops_mutex);
+	if (list_empty(&dfl_port_ops_list))
+		goto done;
+
+	list_for_each_entry(ops, &dfl_port_ops_list, node) {
+		/* match port_ops using the name of platform device */
+		if (!strcmp(pdev->name, ops->name)) {
+			if (!try_module_get(ops->owner))
+				ops = NULL;
+			goto done;
+		}
+	}
+
+	ops = NULL;
+done:
+	mutex_unlock(&dfl_port_ops_mutex);
+	return ops;
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_port_ops_get);
+
+/**
+ * dfl_fpga_port_ops_put - put port ops
+ * @ops: port ops.
+ */
+void dfl_fpga_port_ops_put(struct dfl_fpga_port_ops *ops)
+{
+	if (ops && ops->owner)
+		module_put(ops->owner);
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_port_ops_put);
+
+/**
+ * dfl_fpga_port_ops_add - add port_ops to global list
+ * @ops: port ops to add.
+ */
+void dfl_fpga_port_ops_add(struct dfl_fpga_port_ops *ops)
+{
+	mutex_lock(&dfl_port_ops_mutex);
+	list_add_tail(&ops->node, &dfl_port_ops_list);
+	mutex_unlock(&dfl_port_ops_mutex);
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_port_ops_add);
+
+/**
+ * dfl_fpga_port_ops_del - remove port_ops from global list
+ * @ops: port ops to del.
+ */
+void dfl_fpga_port_ops_del(struct dfl_fpga_port_ops *ops)
+{
+	mutex_lock(&dfl_port_ops_mutex);
+	list_del(&ops->node);
+	mutex_unlock(&dfl_port_ops_mutex);
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_port_ops_del);
+
+/**
+ * dfl_fpga_check_port_id - check the port id
+ * @pdev: port platform device.
+ * @pport_id: port id to compare.
+ *
+ * Return: 1 if port device matches with given port id, otherwise 0.
+ */
+int dfl_fpga_check_port_id(struct platform_device *pdev, void *pport_id)
+{
+	struct dfl_fpga_port_ops *port_ops = dfl_fpga_port_ops_get(pdev);
+	int port_id;
+
+	if (!port_ops || !port_ops->get_id)
+		return 0;
+
+	port_id = port_ops->get_id(pdev);
+	dfl_fpga_port_ops_put(port_ops);
+
+	return port_id == *(int *)pport_id;
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_check_port_id);
+
+/**
+ * dfl_fpga_dev_feature_uinit - uinit for sub features of dfl feature device
+ * @pdev: feature device.
+ */
+void dfl_fpga_dev_feature_uinit(struct platform_device *pdev)
+{
+	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
+	struct dfl_feature *feature;
+
+	dfl_fpga_dev_for_each_feature(pdata, feature)
+		if (feature->ops) {
+			feature->ops->uinit(pdev, feature);
+			feature->ops = NULL;
+		}
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_dev_feature_uinit);
+
+static int dfl_feature_instance_init(struct platform_device *pdev,
+				     struct dfl_feature_platform_data *pdata,
+				     struct dfl_feature *feature,
+				     struct dfl_feature_driver *drv)
+{
+	int ret;
+
+	ret = drv->ops->init(pdev, feature);
+	if (ret)
+		return ret;
+
+	feature->ops = drv->ops;
+
+	return ret;
+}
+
+/**
+ * dfl_fpga_dev_feature_init - init for sub features of dfl feature device
+ * @pdev: feature device.
+ * @feature_drvs: drvs for sub features.
+ *
+ * This function will match sub features with given feature drvs list and
+ * use matched drv to init related sub feature.
+ *
+ * Return: 0 on success, negative error code otherwise.
+ */
+int dfl_fpga_dev_feature_init(struct platform_device *pdev,
+			      struct dfl_feature_driver *feature_drvs)
+{
+	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
+	struct dfl_feature_driver *drv = feature_drvs;
+	struct dfl_feature *feature;
+	int ret;
+
+	while (drv->ops) {
+		dfl_fpga_dev_for_each_feature(pdata, feature) {
+			/* match feature and drv using id */
+			if (feature->id == drv->id) {
+				ret = dfl_feature_instance_init(pdev, pdata,
+								feature, drv);
+				if (ret)
+					goto exit;
+			}
+		}
+		drv++;
+	}
+
+	return 0;
+exit:
+	dfl_fpga_dev_feature_uinit(pdev);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_dev_feature_init);
+
+static void dfl_chardev_uinit(void)
+{
+	int i;
+
+	for (i = 0; i < DFL_FPGA_DEVT_MAX; i++)
+		if (MAJOR(dfl_chrdevs[i].devt)) {
+			unregister_chrdev_region(dfl_chrdevs[i].devt,
+						 MINORMASK);
+			dfl_chrdevs[i].devt = MKDEV(0, 0);
+		}
+}
+
+static int dfl_chardev_init(void)
+{
+	int i, ret;
+
+	for (i = 0; i < DFL_FPGA_DEVT_MAX; i++) {
+		ret = alloc_chrdev_region(&dfl_chrdevs[i].devt, 0, MINORMASK,
+					  dfl_chrdevs[i].name);
+		if (ret)
+			goto exit;
+	}
+
+	return 0;
+
+exit:
+	dfl_chardev_uinit();
+	return ret;
+}
+
+static dev_t dfl_get_devt(enum dfl_fpga_devt_type type, int id)
+{
+	if (type >= DFL_FPGA_DEVT_MAX)
+		return 0;
+
+	return MKDEV(MAJOR(dfl_chrdevs[type].devt), id);
+}
+
+/**
+ * dfl_fpga_dev_ops_register - register cdev ops for feature dev
+ *
+ * @pdev: feature dev.
+ * @fops: file operations for feature dev's cdev.
+ * @owner: owning module/driver.
+ *
+ * Return: 0 on success, negative error code otherwise.
+ */
+int dfl_fpga_dev_ops_register(struct platform_device *pdev,
+			      const struct file_operations *fops,
+			      struct module *owner)
+{
+	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
+
+	cdev_init(&pdata->cdev, fops);
+	pdata->cdev.owner = owner;
+
+	/*
+	 * set parent to the feature device so that its refcount is
+	 * decreased after the last refcount of cdev is gone, that
+	 * makes sure the feature device is valid during device
+	 * file's life-cycle.
+	 */
+	pdata->cdev.kobj.parent = &pdev->dev.kobj;
+
+	return cdev_add(&pdata->cdev, pdev->dev.devt, 1);
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_dev_ops_register);
+
+/**
+ * dfl_fpga_dev_ops_unregister - unregister cdev ops for feature dev
+ * @pdev: feature dev.
+ */
+void dfl_fpga_dev_ops_unregister(struct platform_device *pdev)
+{
+	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
+
+	cdev_del(&pdata->cdev);
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_dev_ops_unregister);
+
+/**
+ * struct build_feature_devs_info - info collected during feature dev build.
+ *
+ * @dev: device to enumerate.
+ * @cdev: the container device for all feature devices.
+ * @feature_dev: current feature device.
+ * @ioaddr: header register region address of feature device in enumeration.
+ * @sub_features: a sub features linked list for feature device in enumeration.
+ * @feature_num: number of sub features for feature device in enumeration.
+ */
+struct build_feature_devs_info {
+	struct device *dev;
+	struct dfl_fpga_cdev *cdev;
+	struct platform_device *feature_dev;
+	void __iomem *ioaddr;
+	struct list_head sub_features;
+	int feature_num;
+};
+
+/**
+ * struct dfl_feature_info - sub feature info collected during feature dev build
+ *
+ * @fid: id of this sub feature.
+ * @mmio_res: mmio resource of this sub feature.
+ * @ioaddr: mapped base address of mmio resource.
+ * @node: node in sub_features linked list.
+ */
+struct dfl_feature_info {
+	u64 fid;
+	struct resource mmio_res;
+	void __iomem *ioaddr;
+	struct list_head node;
+};
+
+static void dfl_fpga_cdev_add_port_dev(struct dfl_fpga_cdev *cdev,
+				       struct platform_device *port)
+{
+	struct dfl_feature_platform_data *pdata = dev_get_platdata(&port->dev);
+
+	mutex_lock(&cdev->lock);
+	list_add(&pdata->node, &cdev->port_dev_list);
+	get_device(&pdata->dev->dev);
+	mutex_unlock(&cdev->lock);
+}
+
+/*
+ * register current feature device, it is called when we need to switch to
+ * another feature parsing or we have parsed all features on given device
+ * feature list.
+ */
+static int build_info_commit_dev(struct build_feature_devs_info *binfo)
+{
+	struct platform_device *fdev = binfo->feature_dev;
+	struct dfl_feature_platform_data *pdata;
+	struct dfl_feature_info *finfo, *p;
+	int ret, index = 0;
+
+	if (!fdev)
+		return 0;
+
+	/*
+	 * we do not need to care for the memory which is associated with
+	 * the platform device. After calling platform_device_unregister(),
+	 * it will be automatically freed by device's release() callback,
+	 * platform_device_release().
+	 */
+	pdata = kzalloc(dfl_feature_platform_data_size(binfo->feature_num),
+			GFP_KERNEL);
+	if (!pdata)
+		return -ENOMEM;
+
+	pdata->dev = fdev;
+	pdata->num = binfo->feature_num;
+	pdata->dfl_cdev = binfo->cdev;
+	mutex_init(&pdata->lock);
+
+	/*
+	 * the count should be initialized to 0 to make sure
+	 *__fpga_port_enable() following __fpga_port_disable()
+	 * works properly for port device.
+	 * and it should always be 0 for fme device.
+	 */
+	WARN_ON(pdata->disable_count);
+
+	fdev->dev.platform_data = pdata;
+
+	/* each sub feature has one MMIO resource */
+	fdev->num_resources = binfo->feature_num;
+	fdev->resource = kcalloc(binfo->feature_num, sizeof(*fdev->resource),
+				 GFP_KERNEL);
+	if (!fdev->resource)
+		return -ENOMEM;
+
+	/* fill features and resource information for feature dev */
+	list_for_each_entry_safe(finfo, p, &binfo->sub_features, node) {
+		struct dfl_feature *feature = &pdata->features[index];
+
+		/* save resource information for each feature */
+		feature->id = finfo->fid;
+		feature->resource_index = index;
+		feature->ioaddr = finfo->ioaddr;
+		fdev->resource[index++] = finfo->mmio_res;
+
+		list_del(&finfo->node);
+		kfree(finfo);
+	}
+
+	ret = platform_device_add(binfo->feature_dev);
+	if (!ret) {
+		if (feature_dev_id_type(binfo->feature_dev) == PORT_ID)
+			dfl_fpga_cdev_add_port_dev(binfo->cdev,
+						   binfo->feature_dev);
+		else
+			binfo->cdev->fme_dev =
+					get_device(&binfo->feature_dev->dev);
+		/*
+		 * reset it to avoid build_info_free() freeing their resource.
+		 *
+		 * The resource of successfully registered feature devices
+		 * will be freed by platform_device_unregister(). See the
+		 * comments in build_info_create_dev().
+		 */
+		binfo->feature_dev = NULL;
+	}
+
+	return ret;
+}
+
+static int
+build_info_create_dev(struct build_feature_devs_info *binfo,
+		      enum dfl_id_type type, void __iomem *ioaddr)
+{
+	struct platform_device *fdev;
+	int ret;
+
+	if (type >= DFL_ID_MAX)
+		return -EINVAL;
+
+	/* we will create a new device, commit current device first */
+	ret = build_info_commit_dev(binfo);
+	if (ret)
+		return ret;
+
+	/*
+	 * we use -ENODEV as the initialization indicator which indicates
+	 * whether the id need to be reclaimed
+	 */
+	fdev = platform_device_alloc(dfl_devs[type].name, -ENODEV);
+	if (!fdev)
+		return -ENOMEM;
+
+	binfo->feature_dev = fdev;
+	binfo->feature_num = 0;
+	binfo->ioaddr = ioaddr;
+	INIT_LIST_HEAD(&binfo->sub_features);
+
+	fdev->id = dfl_id_alloc(type, &fdev->dev);
+	if (fdev->id < 0)
+		return fdev->id;
+
+	fdev->dev.parent = &binfo->cdev->region->dev;
+	fdev->dev.devt = dfl_get_devt(dfl_devs[type].devt_type, fdev->id);
+
+	return 0;
+}
+
+static void build_info_free(struct build_feature_devs_info *binfo)
+{
+	struct dfl_feature_info *finfo, *p;
+
+	/*
+	 * it is a valid id, free it. See comments in
+	 * build_info_create_dev()
+	 */
+	if (binfo->feature_dev && binfo->feature_dev->id >= 0) {
+		dfl_id_free(feature_dev_id_type(binfo->feature_dev),
+			    binfo->feature_dev->id);
+
+		list_for_each_entry_safe(finfo, p, &binfo->sub_features, node) {
+			list_del(&finfo->node);
+			kfree(finfo);
+		}
+	}
+
+	platform_device_put(binfo->feature_dev);
+
+	devm_kfree(binfo->dev, binfo);
+}
+
+static inline u32 feature_size(void __iomem *start)
+{
+	u64 v = readq(start + DFH);
+	u32 ofst = FIELD_GET(DFH_NEXT_HDR_OFST, v);
+	/* workaround for private features with invalid size, use 4K instead */
+	return ofst ? ofst : 4096;
+}
+
+static u64 feature_id(void __iomem *start)
+{
+	u64 v = readq(start + DFH);
+	u16 id = FIELD_GET(DFH_ID, v);
+	u8 type = FIELD_GET(DFH_TYPE, v);
+
+	if (type == DFH_TYPE_FIU)
+		return FEATURE_ID_FIU_HEADER;
+	else if (type == DFH_TYPE_PRIVATE)
+		return id;
+	else if (type == DFH_TYPE_AFU)
+		return FEATURE_ID_AFU;
+
+	WARN_ON(1);
+	return 0;
+}
+
+/*
+ * when create sub feature instances, for private features, it doesn't need
+ * to provide resource size and feature id as they could be read from DFH
+ * register. For afu sub feature, its register region only contains user
+ * defined registers, so never trust any information from it, just use the
+ * resource size information provided by its parent FIU.
+ */
+static int
+create_feature_instance(struct build_feature_devs_info *binfo,
+			struct dfl_fpga_enum_dfl *dfl, resource_size_t ofst,
+			resource_size_t size, u64 fid)
+{
+	struct dfl_feature_info *finfo;
+
+	/* read feature size and id if inputs are invalid */
+	size = size ? size : feature_size(dfl->ioaddr + ofst);
+	fid = fid ? fid : feature_id(dfl->ioaddr + ofst);
+
+	if (dfl->len - ofst < size)
+		return -EINVAL;
+
+	finfo = kzalloc(sizeof(*finfo), GFP_KERNEL);
+	if (!finfo)
+		return -ENOMEM;
+
+	finfo->fid = fid;
+	finfo->mmio_res.start = dfl->start + ofst;
+	finfo->mmio_res.end = finfo->mmio_res.start + size - 1;
+	finfo->mmio_res.flags = IORESOURCE_MEM;
+	finfo->ioaddr = dfl->ioaddr + ofst;
+
+	list_add_tail(&finfo->node, &binfo->sub_features);
+	binfo->feature_num++;
+
+	return 0;
+}
+
+static int parse_feature_port_afu(struct build_feature_devs_info *binfo,
+				  struct dfl_fpga_enum_dfl *dfl,
+				  resource_size_t ofst)
+{
+	u64 v = readq(binfo->ioaddr + PORT_HDR_CAP);
+	u32 size = FIELD_GET(PORT_CAP_MMIO_SIZE, v) << 10;
+
+	WARN_ON(!size);
+
+	return create_feature_instance(binfo, dfl, ofst, size, FEATURE_ID_AFU);
+}
+
+static int parse_feature_afu(struct build_feature_devs_info *binfo,
+			     struct dfl_fpga_enum_dfl *dfl,
+			     resource_size_t ofst)
+{
+	if (!binfo->feature_dev) {
+		dev_err(binfo->dev, "this AFU does not belong to any FIU.\n");
+		return -EINVAL;
+	}
+
+	switch (feature_dev_id_type(binfo->feature_dev)) {
+	case PORT_ID:
+		return parse_feature_port_afu(binfo, dfl, ofst);
+	default:
+		dev_info(binfo->dev, "AFU belonging to FIU %s is not supported yet.\n",
+			 binfo->feature_dev->name);
+	}
+
+	return 0;
+}
+
+static int parse_feature_fiu(struct build_feature_devs_info *binfo,
+			     struct dfl_fpga_enum_dfl *dfl,
+			     resource_size_t ofst)
+{
+	u32 id, offset;
+	u64 v;
+	int ret = 0;
+
+	v = readq(dfl->ioaddr + ofst + DFH);
+	id = FIELD_GET(DFH_ID, v);
+
+	/* create platform device for dfl feature dev */
+	ret = build_info_create_dev(binfo, dfh_id_to_type(id),
+				    dfl->ioaddr + ofst);
+	if (ret)
+		return ret;
+
+	ret = create_feature_instance(binfo, dfl, ofst, 0, 0);
+	if (ret)
+		return ret;
+	/*
+	 * find and parse FIU's child AFU via its NEXT_AFU register.
+	 * please note that only Port has valid NEXT_AFU pointer per spec.
+	 */
+	v = readq(dfl->ioaddr + ofst + NEXT_AFU);
+
+	offset = FIELD_GET(NEXT_AFU_NEXT_DFH_OFST, v);
+	if (offset)
+		return parse_feature_afu(binfo, dfl, ofst + offset);
+
+	dev_dbg(binfo->dev, "No AFUs detected on FIU %d\n", id);
+
+	return ret;
+}
+
+static int parse_feature_private(struct build_feature_devs_info *binfo,
+				 struct dfl_fpga_enum_dfl *dfl,
+				 resource_size_t ofst)
+{
+	if (!binfo->feature_dev) {
+		dev_err(binfo->dev, "the private feature %llx does not belong to any AFU.\n",
+			(unsigned long long)feature_id(dfl->ioaddr + ofst));
+		return -EINVAL;
+	}
+
+	return create_feature_instance(binfo, dfl, ofst, 0, 0);
+}
+
+/**
+ * parse_feature - parse a feature on given device feature list
+ *
+ * @binfo: build feature devices information.
+ * @dfl: device feature list to parse
+ * @ofst: offset to feature header on this device feature list
+ */
+static int parse_feature(struct build_feature_devs_info *binfo,
+			 struct dfl_fpga_enum_dfl *dfl, resource_size_t ofst)
+{
+	u64 v;
+	u32 type;
+
+	v = readq(dfl->ioaddr + ofst + DFH);
+	type = FIELD_GET(DFH_TYPE, v);
+
+	switch (type) {
+	case DFH_TYPE_AFU:
+		return parse_feature_afu(binfo, dfl, ofst);
+	case DFH_TYPE_PRIVATE:
+		return parse_feature_private(binfo, dfl, ofst);
+	case DFH_TYPE_FIU:
+		return parse_feature_fiu(binfo, dfl, ofst);
+	default:
+		dev_info(binfo->dev,
+			 "Feature Type %x is not supported.\n", type);
+	}
+
+	return 0;
+}
+
+static int parse_feature_list(struct build_feature_devs_info *binfo,
+			      struct dfl_fpga_enum_dfl *dfl)
+{
+	void __iomem *start = dfl->ioaddr;
+	void __iomem *end = dfl->ioaddr + dfl->len;
+	int ret = 0;
+	u32 ofst = 0;
+	u64 v;
+
+	/* walk through the device feature list via DFH's next DFH pointer. */
+	for (; start < end; start += ofst) {
+		if (end - start < DFH_SIZE) {
+			dev_err(binfo->dev, "The region is too small to contain a feature.\n");
+			return -EINVAL;
+		}
+
+		ret = parse_feature(binfo, dfl, start - dfl->ioaddr);
+		if (ret)
+			return ret;
+
+		v = readq(start + DFH);
+		ofst = FIELD_GET(DFH_NEXT_HDR_OFST, v);
+
+		/* stop parsing if EOL(End of List) is set or offset is 0 */
+		if ((v & DFH_EOL) || !ofst)
+			break;
+	}
+
+	/* commit current feature device when reach the end of list */
+	return build_info_commit_dev(binfo);
+}
+
+struct dfl_fpga_enum_info *dfl_fpga_enum_info_alloc(struct device *dev)
+{
+	struct dfl_fpga_enum_info *info;
+
+	get_device(dev);
+
+	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
+	if (!info) {
+		put_device(dev);
+		return NULL;
+	}
+
+	info->dev = dev;
+	INIT_LIST_HEAD(&info->dfls);
+
+	return info;
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_enum_info_alloc);
+
+void dfl_fpga_enum_info_free(struct dfl_fpga_enum_info *info)
+{
+	struct dfl_fpga_enum_dfl *tmp, *dfl;
+	struct device *dev;
+
+	if (!info)
+		return;
+
+	dev = info->dev;
+
+	/* remove all device feature lists in the list. */
+	list_for_each_entry_safe(dfl, tmp, &info->dfls, node) {
+		list_del(&dfl->node);
+		devm_kfree(dev, dfl);
+	}
+
+	devm_kfree(dev, info);
+	put_device(dev);
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_enum_info_free);
+
+/**
+ * dfl_fpga_enum_info_add_dfl - add info of a device feature list to enum info
+ *
+ * @info: ptr to dfl_fpga_enum_info
+ * @start: mmio resource address of the device feature list.
+ * @len: mmio resource length of the device feature list.
+ * @ioaddr: mapped mmio resource address of the device feature list.
+ *
+ * One FPGA device may have one or more Device Feature Lists (DFLs), use this
+ * function to add information of each DFL to common data structure for next
+ * step enumeration.
+ *
+ * Return: 0 on success, negative error code otherwise.
+ */
+int dfl_fpga_enum_info_add_dfl(struct dfl_fpga_enum_info *info,
+			       resource_size_t start, resource_size_t len,
+			       void __iomem *ioaddr)
+{
+	struct dfl_fpga_enum_dfl *dfl;
+
+	dfl = devm_kzalloc(info->dev, sizeof(*dfl), GFP_KERNEL);
+	if (!dfl)
+		return -ENOMEM;
+
+	dfl->start = start;
+	dfl->len = len;
+	dfl->ioaddr = ioaddr;
+
+	list_add_tail(&dfl->node, &info->dfls);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_enum_info_add_dfl);
+
+static int remove_feature_dev(struct device *dev, void *data)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	enum dfl_id_type type = feature_dev_id_type(pdev);
+	int id = pdev->id;
+
+	platform_device_unregister(pdev);
+
+	dfl_id_free(type, id);
+
+	return 0;
+}
+
+static void remove_feature_devs(struct dfl_fpga_cdev *cdev)
+{
+	device_for_each_child(&cdev->region->dev, NULL, remove_feature_dev);
+}
+
+/**
+ * dfl_fpga_feature_devs_enumerate - enumerate feature devices
+ * @info: information for enumeration.
+ *
+ * This function creates a container device (base FPGA region), enumerates
+ * feature devices based on the enumeration info and creates platform devices
+ * under the container device.
+ *
+ * Return: dfl_fpga_cdev struct on success, -errno on failure
+ */
+struct dfl_fpga_cdev *
+dfl_fpga_feature_devs_enumerate(struct dfl_fpga_enum_info *info)
+{
+	struct build_feature_devs_info *binfo;
+	struct dfl_fpga_enum_dfl *dfl;
+	struct dfl_fpga_cdev *cdev;
+	int ret = 0;
+
+	if (!info->dev)
+		return ERR_PTR(-ENODEV);
+
+	cdev = devm_kzalloc(info->dev, sizeof(*cdev), GFP_KERNEL);
+	if (!cdev)
+		return ERR_PTR(-ENOMEM);
+
+	cdev->region = fpga_region_create(info->dev, NULL, NULL);
+	if (!cdev->region) {
+		ret = -ENOMEM;
+		goto free_cdev_exit;
+	}
+
+	cdev->parent = info->dev;
+	mutex_init(&cdev->lock);
+	INIT_LIST_HEAD(&cdev->port_dev_list);
+
+	ret = fpga_region_register(cdev->region);
+	if (ret)
+		goto free_region_exit;
+
+	/* create and init build info for enumeration */
+	binfo = devm_kzalloc(info->dev, sizeof(*binfo), GFP_KERNEL);
+	if (!binfo) {
+		ret = -ENOMEM;
+		goto unregister_region_exit;
+	}
+
+	binfo->dev = info->dev;
+	binfo->cdev = cdev;
+
+	/*
+	 * start enumeration for all feature devices based on Device Feature
+	 * Lists.
+	 */
+	list_for_each_entry(dfl, &info->dfls, node) {
+		ret = parse_feature_list(binfo, dfl);
+		if (ret) {
+			remove_feature_devs(cdev);
+			build_info_free(binfo);
+			goto unregister_region_exit;
+		}
+	}
+
+	build_info_free(binfo);
+
+	return cdev;
+
+unregister_region_exit:
+	fpga_region_unregister(cdev->region);
+free_region_exit:
+	fpga_region_free(cdev->region);
+free_cdev_exit:
+	devm_kfree(info->dev, cdev);
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_feature_devs_enumerate);
+
+/**
+ * dfl_fpga_feature_devs_remove - remove all feature devices
+ * @cdev: fpga container device.
+ *
+ * Remove the container device and all feature devices under given container
+ * devices.
+ */
+void dfl_fpga_feature_devs_remove(struct dfl_fpga_cdev *cdev)
+{
+	struct dfl_feature_platform_data *pdata, *ptmp;
+
+	remove_feature_devs(cdev);
+
+	mutex_lock(&cdev->lock);
+	if (cdev->fme_dev) {
+		/* the fme should be unregistered. */
+		WARN_ON(device_is_registered(cdev->fme_dev));
+		put_device(cdev->fme_dev);
+	}
+
+	list_for_each_entry_safe(pdata, ptmp, &cdev->port_dev_list, node) {
+		struct platform_device *port_dev = pdata->dev;
+
+		/* the port should be unregistered. */
+		WARN_ON(device_is_registered(&port_dev->dev));
+		list_del(&pdata->node);
+		put_device(&port_dev->dev);
+	}
+	mutex_unlock(&cdev->lock);
+
+	fpga_region_unregister(cdev->region);
+	devm_kfree(cdev->parent, cdev);
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_feature_devs_remove);
+
+/**
+ * __dfl_fpga_cdev_find_port - find a port under given container device
+ *
+ * @cdev: container device
+ * @data: data passed to match function
+ * @match: match function used to find specific port from the port device list
+ *
+ * Find a port device under container device. This function needs to be
+ * invoked with lock held.
+ *
+ * Return: pointer to port's platform device if successful, NULL otherwise.
+ *
+ * NOTE: you will need to drop the device reference with put_device() after use.
+ */
+struct platform_device *
+__dfl_fpga_cdev_find_port(struct dfl_fpga_cdev *cdev, void *data,
+			  int (*match)(struct platform_device *, void *))
+{
+	struct dfl_feature_platform_data *pdata;
+	struct platform_device *port_dev;
+
+	list_for_each_entry(pdata, &cdev->port_dev_list, node) {
+		port_dev = pdata->dev;
+
+		if (match(port_dev, data) && get_device(&port_dev->dev))
+			return port_dev;
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(__dfl_fpga_cdev_find_port);
+
+static int __init dfl_fpga_init(void)
+{
+	int ret;
+
+	dfl_ids_init();
+
+	ret = dfl_chardev_init();
+	if (ret)
+		dfl_ids_destroy();
+
+	return ret;
+}
+
+static void __exit dfl_fpga_exit(void)
+{
+	dfl_chardev_uinit();
+	dfl_ids_destroy();
+}
+
+module_init(dfl_fpga_init);
+module_exit(dfl_fpga_exit);
+
+MODULE_DESCRIPTION("FPGA Device Feature List (DFL) Support");
+MODULE_AUTHOR("Intel Corporation");
+MODULE_LICENSE("GPL v2");