fpga: add device feature list support

Device Feature List (DFL) defines a feature list structure that creates
a linked list of feature headers within the MMIO space to provide an
extensible way of adding features. This patch introduces a kernel module
to provide basic infrastructure to support FPGA devices which implement
the Device Feature List.

Usually there will be different features and their sub features linked into
the DFL. This code provides common APIs for feature enumeration, it creates
a container device (FPGA base region), walks through the DFLs and creates
platform devices for feature devices (Currently it only supports two
different feature devices, FPGA Management Engine (FME) and Port which
the Accelerator Function Unit (AFU) connected to). In order to enumerate
the DFLs, the common APIs required low level driver to provide necessary
enumeration information (e.g. address for each device feature list for
given device) and fill it to the dfl_fpga_enum_info data structure. Please
refer to below description for APIs added for enumeration.

Functions for enumeration information preparation:
 *dfl_fpga_enum_info_alloc
   allocate enumeration information data structure.

 *dfl_fpga_enum_info_add_dfl
   add a device feature list to dfl_fpga_enum_info data structure.

 *dfl_fpga_enum_info_free
   free dfl_fpga_enum_info data structure and related resources.

Functions for feature device enumeration:
 *dfl_fpga_feature_devs_enumerate
   enumerate feature devices and return container device.

 *dfl_fpga_feature_devs_remove
   remove feature devices under given container device.

Signed-off-by: Tim Whisonant <tim.whisonant@intel.com>
Signed-off-by: Enno Luebbers <enno.luebbers@intel.com>
Signed-off-by: Shiva Rao <shiva.rao@intel.com>
Signed-off-by: Christopher Rauer <christopher.rauer@intel.com>
Signed-off-by: Zhang Yi <yi.z.zhang@intel.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Wu Hao <hao.wu@intel.com>
Acked-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 721 insertions, 0 deletions

diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
new file mode 100644
index 000000000000..d1dff360ea14
--- /dev/null
+++ b/drivers/fpga/dfl.c
@@ -0,0 +1,721 @@
+// 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).
+ */
+enum dfl_id_type {
+	FME_ID,		/* fme id allocation and mapping */
+	PORT_ID,	/* port id allocation and mapping */
+	DFL_ID_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.
+ */
+struct dfl_dev_info {
+	const char *name;
+	u32 dfh_id;
+	struct idr id;
+};
+
+/* 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},
+	{.name = DFL_FPGA_FEATURE_DEV_PORT, .dfh_id = DFH_ID_FIU_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;
+}
+
+/**
+ * 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;
+
+	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);
+
+static int __init dfl_fpga_init(void)
+{
+	dfl_ids_init();
+
+	return 0;
+}
+
+static void __exit dfl_fpga_exit(void)
+{
+	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");