Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2037 insertions, 0 deletions

diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
new file mode 100644
index 0000000000..dd7a783d53
--- /dev/null
+++ b/drivers/fpga/dfl.c
@@ -0,0 +1,2037 @@
+// 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/dfl.h>
+#include <linux/fpga-dfl.h>
+#include <linux/module.h>
+#include <linux/overflow.h>
+#include <linux/uaccess.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_fpga_devt_type {
+	DFL_FPGA_DEVT_FME,
+	DFL_FPGA_DEVT_PORT,
+	DFL_FPGA_DEVT_MAX,
+};
+
+static struct lock_class_key dfl_pdata_keys[DFL_ID_MAX];
+
+static const char *dfl_pdata_key_strings[DFL_ID_MAX] = {
+	"dfl-fme-pdata",
+	"dfl-port-pdata",
+};
+
+/**
+ * struct 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;
+	u16 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},
+};
+
+/**
+ * struct 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(u16 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_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
+	struct dfl_fpga_port_ops *port_ops;
+
+	if (pdata->id != FEATURE_DEV_ID_UNUSED)
+		return pdata->id == *(int *)pport_id;
+
+	port_ops = dfl_fpga_port_ops_get(pdev);
+	if (!port_ops || !port_ops->get_id)
+		return 0;
+
+	pdata->id = port_ops->get_id(pdev);
+	dfl_fpga_port_ops_put(port_ops);
+
+	return pdata->id == *(int *)pport_id;
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_check_port_id);
+
+static DEFINE_IDA(dfl_device_ida);
+
+static const struct dfl_device_id *
+dfl_match_one_device(const struct dfl_device_id *id, struct dfl_device *ddev)
+{
+	if (id->type == ddev->type && id->feature_id == ddev->feature_id)
+		return id;
+
+	return NULL;
+}
+
+static int dfl_bus_match(struct device *dev, struct device_driver *drv)
+{
+	struct dfl_device *ddev = to_dfl_dev(dev);
+	struct dfl_driver *ddrv = to_dfl_drv(drv);
+	const struct dfl_device_id *id_entry;
+
+	id_entry = ddrv->id_table;
+	if (id_entry) {
+		while (id_entry->feature_id) {
+			if (dfl_match_one_device(id_entry, ddev)) {
+				ddev->id_entry = id_entry;
+				return 1;
+			}
+			id_entry++;
+		}
+	}
+
+	return 0;
+}
+
+static int dfl_bus_probe(struct device *dev)
+{
+	struct dfl_driver *ddrv = to_dfl_drv(dev->driver);
+	struct dfl_device *ddev = to_dfl_dev(dev);
+
+	return ddrv->probe(ddev);
+}
+
+static void dfl_bus_remove(struct device *dev)
+{
+	struct dfl_driver *ddrv = to_dfl_drv(dev->driver);
+	struct dfl_device *ddev = to_dfl_dev(dev);
+
+	if (ddrv->remove)
+		ddrv->remove(ddev);
+}
+
+static int dfl_bus_uevent(const struct device *dev, struct kobj_uevent_env *env)
+{
+	const struct dfl_device *ddev = to_dfl_dev(dev);
+
+	return add_uevent_var(env, "MODALIAS=dfl:t%04Xf%04X",
+			      ddev->type, ddev->feature_id);
+}
+
+static ssize_t
+type_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct dfl_device *ddev = to_dfl_dev(dev);
+
+	return sprintf(buf, "0x%x\n", ddev->type);
+}
+static DEVICE_ATTR_RO(type);
+
+static ssize_t
+feature_id_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct dfl_device *ddev = to_dfl_dev(dev);
+
+	return sprintf(buf, "0x%x\n", ddev->feature_id);
+}
+static DEVICE_ATTR_RO(feature_id);
+
+static struct attribute *dfl_dev_attrs[] = {
+	&dev_attr_type.attr,
+	&dev_attr_feature_id.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(dfl_dev);
+
+static struct bus_type dfl_bus_type = {
+	.name		= "dfl",
+	.match		= dfl_bus_match,
+	.probe		= dfl_bus_probe,
+	.remove		= dfl_bus_remove,
+	.uevent		= dfl_bus_uevent,
+	.dev_groups	= dfl_dev_groups,
+};
+
+static void release_dfl_dev(struct device *dev)
+{
+	struct dfl_device *ddev = to_dfl_dev(dev);
+
+	if (ddev->mmio_res.parent)
+		release_resource(&ddev->mmio_res);
+
+	kfree(ddev->params);
+
+	ida_free(&dfl_device_ida, ddev->id);
+	kfree(ddev->irqs);
+	kfree(ddev);
+}
+
+static struct dfl_device *
+dfl_dev_add(struct dfl_feature_platform_data *pdata,
+	    struct dfl_feature *feature)
+{
+	struct platform_device *pdev = pdata->dev;
+	struct resource *parent_res;
+	struct dfl_device *ddev;
+	int id, i, ret;
+
+	ddev = kzalloc(sizeof(*ddev), GFP_KERNEL);
+	if (!ddev)
+		return ERR_PTR(-ENOMEM);
+
+	id = ida_alloc(&dfl_device_ida, GFP_KERNEL);
+	if (id < 0) {
+		dev_err(&pdev->dev, "unable to get id\n");
+		kfree(ddev);
+		return ERR_PTR(id);
+	}
+
+	/* freeing resources by put_device() after device_initialize() */
+	device_initialize(&ddev->dev);
+	ddev->dev.parent = &pdev->dev;
+	ddev->dev.bus = &dfl_bus_type;
+	ddev->dev.release = release_dfl_dev;
+	ddev->id = id;
+	ret = dev_set_name(&ddev->dev, "dfl_dev.%d", id);
+	if (ret)
+		goto put_dev;
+
+	ddev->type = feature_dev_id_type(pdev);
+	ddev->feature_id = feature->id;
+	ddev->revision = feature->revision;
+	ddev->dfh_version = feature->dfh_version;
+	ddev->cdev = pdata->dfl_cdev;
+	if (feature->param_size) {
+		ddev->params = kmemdup(feature->params, feature->param_size, GFP_KERNEL);
+		if (!ddev->params) {
+			ret = -ENOMEM;
+			goto put_dev;
+		}
+		ddev->param_size = feature->param_size;
+	}
+
+	/* add mmio resource */
+	parent_res = &pdev->resource[feature->resource_index];
+	ddev->mmio_res.flags = IORESOURCE_MEM;
+	ddev->mmio_res.start = parent_res->start;
+	ddev->mmio_res.end = parent_res->end;
+	ddev->mmio_res.name = dev_name(&ddev->dev);
+	ret = insert_resource(parent_res, &ddev->mmio_res);
+	if (ret) {
+		dev_err(&pdev->dev, "%s failed to claim resource: %pR\n",
+			dev_name(&ddev->dev), &ddev->mmio_res);
+		goto put_dev;
+	}
+
+	/* then add irq resource */
+	if (feature->nr_irqs) {
+		ddev->irqs = kcalloc(feature->nr_irqs,
+				     sizeof(*ddev->irqs), GFP_KERNEL);
+		if (!ddev->irqs) {
+			ret = -ENOMEM;
+			goto put_dev;
+		}
+
+		for (i = 0; i < feature->nr_irqs; i++)
+			ddev->irqs[i] = feature->irq_ctx[i].irq;
+
+		ddev->num_irqs = feature->nr_irqs;
+	}
+
+	ret = device_add(&ddev->dev);
+	if (ret)
+		goto put_dev;
+
+	dev_dbg(&pdev->dev, "add dfl_dev: %s\n", dev_name(&ddev->dev));
+	return ddev;
+
+put_dev:
+	/* calls release_dfl_dev() which does the clean up  */
+	put_device(&ddev->dev);
+	return ERR_PTR(ret);
+}
+
+static void dfl_devs_remove(struct dfl_feature_platform_data *pdata)
+{
+	struct dfl_feature *feature;
+
+	dfl_fpga_dev_for_each_feature(pdata, feature) {
+		if (feature->ddev) {
+			device_unregister(&feature->ddev->dev);
+			feature->ddev = NULL;
+		}
+	}
+}
+
+static int dfl_devs_add(struct dfl_feature_platform_data *pdata)
+{
+	struct dfl_feature *feature;
+	struct dfl_device *ddev;
+	int ret;
+
+	dfl_fpga_dev_for_each_feature(pdata, feature) {
+		if (feature->ioaddr)
+			continue;
+
+		if (feature->ddev) {
+			ret = -EEXIST;
+			goto err;
+		}
+
+		ddev = dfl_dev_add(pdata, feature);
+		if (IS_ERR(ddev)) {
+			ret = PTR_ERR(ddev);
+			goto err;
+		}
+
+		feature->ddev = ddev;
+	}
+
+	return 0;
+
+err:
+	dfl_devs_remove(pdata);
+	return ret;
+}
+
+int __dfl_driver_register(struct dfl_driver *dfl_drv, struct module *owner)
+{
+	if (!dfl_drv || !dfl_drv->probe || !dfl_drv->id_table)
+		return -EINVAL;
+
+	dfl_drv->drv.owner = owner;
+	dfl_drv->drv.bus = &dfl_bus_type;
+
+	return driver_register(&dfl_drv->drv);
+}
+EXPORT_SYMBOL(__dfl_driver_register);
+
+void dfl_driver_unregister(struct dfl_driver *dfl_drv)
+{
+	driver_unregister(&dfl_drv->drv);
+}
+EXPORT_SYMBOL(dfl_driver_unregister);
+
+#define is_header_feature(feature) ((feature)->id == FEATURE_ID_FIU_HEADER)
+
+/**
+ * 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_devs_remove(pdata);
+
+	dfl_fpga_dev_for_each_feature(pdata, feature) {
+		if (feature->ops) {
+			if (feature->ops->uinit)
+				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)
+{
+	void __iomem *base;
+	int ret = 0;
+
+	if (!is_header_feature(feature)) {
+		base = devm_platform_ioremap_resource(pdev,
+						      feature->resource_index);
+		if (IS_ERR(base)) {
+			dev_err(&pdev->dev,
+				"ioremap failed for feature 0x%x!\n",
+				feature->id);
+			return PTR_ERR(base);
+		}
+
+		feature->ioaddr = base;
+	}
+
+	if (drv->ops->init) {
+		ret = drv->ops->init(pdev, feature);
+		if (ret)
+			return ret;
+	}
+
+	feature->ops = drv->ops;
+
+	return ret;
+}
+
+static bool dfl_feature_drv_match(struct dfl_feature *feature,
+				  struct dfl_feature_driver *driver)
+{
+	const struct dfl_feature_id *ids = driver->id_table;
+
+	if (ids) {
+		while (ids->id) {
+			if (ids->id == feature->id)
+				return true;
+			ids++;
+		}
+	}
+	return false;
+}
+
+/**
+ * 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) {
+			if (dfl_feature_drv_match(feature, drv)) {
+				ret = dfl_feature_instance_init(pdev, pdata,
+								feature, drv);
+				if (ret)
+					goto exit;
+			}
+		}
+		drv++;
+	}
+
+	ret = dfl_devs_add(pdata);
+	if (ret)
+		goto exit;
+
+	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 + 1);
+			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 + 1, 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.
+ * @nr_irqs: number of irqs for all feature devices.
+ * @irq_table: Linux IRQ numbers for all irqs, indexed by local irq index of
+ *	       this device.
+ * @feature_dev: current feature device.
+ * @ioaddr: header register region address of current FIU in enumeration.
+ * @start: register resource start of current FIU.
+ * @len: max register resource length of current FIU.
+ * @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;
+	unsigned int nr_irqs;
+	int *irq_table;
+
+	struct platform_device *feature_dev;
+	void __iomem *ioaddr;
+	resource_size_t start;
+	resource_size_t len;
+	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.
+ * @revision: revision of this sub feature
+ * @dfh_version: version of Device Feature Header (DFH)
+ * @mmio_res: mmio resource of this sub feature.
+ * @ioaddr: mapped base address of mmio resource.
+ * @node: node in sub_features linked list.
+ * @irq_base: start of irq index in this sub feature.
+ * @nr_irqs: number of irqs of this sub feature.
+ * @param_size: size DFH parameters.
+ * @params: DFH parameter data.
+ */
+struct dfl_feature_info {
+	u16 fid;
+	u8 revision;
+	u8 dfh_version;
+	struct resource mmio_res;
+	void __iomem *ioaddr;
+	struct list_head node;
+	unsigned int irq_base;
+	unsigned int nr_irqs;
+	unsigned int param_size;
+	u64 params[];
+};
+
+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;
+	enum dfl_id_type type;
+	int ret, index = 0, res_idx = 0;
+
+	type = feature_dev_id_type(fdev);
+	if (WARN_ON_ONCE(type >= DFL_ID_MAX))
+		return -EINVAL;
+
+	/*
+	 * 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(struct_size(pdata, features, binfo->feature_num), GFP_KERNEL);
+	if (!pdata)
+		return -ENOMEM;
+
+	pdata->dev = fdev;
+	pdata->num = binfo->feature_num;
+	pdata->dfl_cdev = binfo->cdev;
+	pdata->id = FEATURE_DEV_ID_UNUSED;
+	mutex_init(&pdata->lock);
+	lockdep_set_class_and_name(&pdata->lock, &dfl_pdata_keys[type],
+				   dfl_pdata_key_strings[type]);
+
+	/*
+	 * 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++];
+		struct dfl_feature_irq_ctx *ctx;
+		unsigned int i;
+
+		/* save resource information for each feature */
+		feature->dev = fdev;
+		feature->id = finfo->fid;
+		feature->revision = finfo->revision;
+		feature->dfh_version = finfo->dfh_version;
+
+		if (finfo->param_size) {
+			feature->params = devm_kmemdup(binfo->dev,
+						       finfo->params, finfo->param_size,
+						       GFP_KERNEL);
+			if (!feature->params)
+				return -ENOMEM;
+
+			feature->param_size = finfo->param_size;
+		}
+		/*
+		 * the FIU header feature has some fundamental functions (sriov
+		 * set, port enable/disable) needed for the dfl bus device and
+		 * other sub features. So its mmio resource should be mapped by
+		 * DFL bus device. And we should not assign it to feature
+		 * devices (dfl-fme/afu) again.
+		 */
+		if (is_header_feature(feature)) {
+			feature->resource_index = -1;
+			feature->ioaddr =
+				devm_ioremap_resource(binfo->dev,
+						      &finfo->mmio_res);
+			if (IS_ERR(feature->ioaddr))
+				return PTR_ERR(feature->ioaddr);
+		} else {
+			feature->resource_index = res_idx;
+			fdev->resource[res_idx++] = finfo->mmio_res;
+		}
+
+		if (finfo->nr_irqs) {
+			ctx = devm_kcalloc(binfo->dev, finfo->nr_irqs,
+					   sizeof(*ctx), GFP_KERNEL);
+			if (!ctx)
+				return -ENOMEM;
+
+			for (i = 0; i < finfo->nr_irqs; i++)
+				ctx[i].irq =
+					binfo->irq_table[finfo->irq_base + i];
+
+			feature->irq_ctx = ctx;
+			feature->nr_irqs = finfo->nr_irqs;
+		}
+
+		list_del(&finfo->node);
+		kfree(finfo);
+	}
+
+	ret = platform_device_add(binfo->feature_dev);
+	if (!ret) {
+		if (type == 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)
+{
+	struct platform_device *fdev;
+
+	if (type >= DFL_ID_MAX)
+		return -EINVAL;
+
+	/*
+	 * 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;
+
+	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(u64 value)
+{
+	u32 ofst = FIELD_GET(DFH_NEXT_HDR_OFST, value);
+	/* workaround for private features with invalid size, use 4K instead */
+	return ofst ? ofst : 4096;
+}
+
+static u16 feature_id(u64 value)
+{
+	u16 id = FIELD_GET(DFH_ID, value);
+	u8 type = FIELD_GET(DFH_TYPE, value);
+
+	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;
+}
+
+static u64 *find_param(u64 *params, resource_size_t max, int param_id)
+{
+	u64 *end = params + max / sizeof(u64);
+	u64 v, next;
+
+	while (params < end) {
+		v = *params;
+		if (param_id == FIELD_GET(DFHv1_PARAM_HDR_ID, v))
+			return params;
+
+		if (FIELD_GET(DFHv1_PARAM_HDR_NEXT_EOP, v))
+			break;
+
+		next = FIELD_GET(DFHv1_PARAM_HDR_NEXT_OFFSET, v);
+		params += next;
+	}
+
+	return NULL;
+}
+
+/**
+ * dfh_find_param() - find parameter block for the given parameter id
+ * @dfl_dev: dfl device
+ * @param_id: id of dfl parameter
+ * @psize: destination to store size of parameter data in bytes
+ *
+ * Return: pointer to start of parameter data, PTR_ERR otherwise.
+ */
+void *dfh_find_param(struct dfl_device *dfl_dev, int param_id, size_t *psize)
+{
+	u64 *phdr = find_param(dfl_dev->params, dfl_dev->param_size, param_id);
+
+	if (!phdr)
+		return ERR_PTR(-ENOENT);
+
+	if (psize)
+		*psize = (FIELD_GET(DFHv1_PARAM_HDR_NEXT_OFFSET, *phdr) - 1) * sizeof(u64);
+
+	return phdr + 1;
+}
+EXPORT_SYMBOL_GPL(dfh_find_param);
+
+static int parse_feature_irqs(struct build_feature_devs_info *binfo,
+			      resource_size_t ofst, struct dfl_feature_info *finfo)
+{
+	void __iomem *base = binfo->ioaddr + ofst;
+	unsigned int i, ibase, inr = 0;
+	void *params = finfo->params;
+	enum dfl_id_type type;
+	u16 fid = finfo->fid;
+	int virq;
+	u64 *p;
+	u64 v;
+
+	switch (finfo->dfh_version) {
+	case 0:
+		/*
+		 * DFHv0 only provides MMIO resource information for each feature
+		 * in the DFL header.  There is no generic interrupt information.
+		 * Instead, features with interrupt functionality provide
+		 * the information in feature specific registers.
+		 */
+		type = feature_dev_id_type(binfo->feature_dev);
+		if (type == PORT_ID) {
+			switch (fid) {
+			case PORT_FEATURE_ID_UINT:
+				v = readq(base + PORT_UINT_CAP);
+				ibase = FIELD_GET(PORT_UINT_CAP_FST_VECT, v);
+				inr = FIELD_GET(PORT_UINT_CAP_INT_NUM, v);
+				break;
+			case PORT_FEATURE_ID_ERROR:
+				v = readq(base + PORT_ERROR_CAP);
+				ibase = FIELD_GET(PORT_ERROR_CAP_INT_VECT, v);
+				inr = FIELD_GET(PORT_ERROR_CAP_SUPP_INT, v);
+				break;
+			}
+		} else if (type == FME_ID) {
+			switch (fid) {
+			case FME_FEATURE_ID_GLOBAL_ERR:
+				v = readq(base + FME_ERROR_CAP);
+				ibase = FIELD_GET(FME_ERROR_CAP_INT_VECT, v);
+				inr = FIELD_GET(FME_ERROR_CAP_SUPP_INT, v);
+				break;
+			}
+		}
+		break;
+
+	case 1:
+		/*
+		 * DFHv1 provides interrupt resource information in DFHv1
+		 * parameter blocks.
+		 */
+		p = find_param(params, finfo->param_size, DFHv1_PARAM_ID_MSI_X);
+		if (!p)
+			break;
+
+		p++;
+		ibase = FIELD_GET(DFHv1_PARAM_MSI_X_STARTV, *p);
+		inr = FIELD_GET(DFHv1_PARAM_MSI_X_NUMV, *p);
+		break;
+
+	default:
+		dev_warn(binfo->dev, "unexpected DFH version %d\n", finfo->dfh_version);
+		break;
+	}
+
+	if (!inr) {
+		finfo->irq_base = 0;
+		finfo->nr_irqs = 0;
+		return 0;
+	}
+
+	dev_dbg(binfo->dev, "feature: 0x%x, irq_base: %u, nr_irqs: %u\n",
+		fid, ibase, inr);
+
+	if (ibase + inr > binfo->nr_irqs) {
+		dev_err(binfo->dev,
+			"Invalid interrupt number in feature 0x%x\n", fid);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < inr; i++) {
+		virq = binfo->irq_table[ibase + i];
+		if (virq < 0 || virq > NR_IRQS) {
+			dev_err(binfo->dev,
+				"Invalid irq table entry for feature 0x%x\n",
+				fid);
+			return -EINVAL;
+		}
+	}
+
+	finfo->irq_base = ibase;
+	finfo->nr_irqs = inr;
+
+	return 0;
+}
+
+static int dfh_get_param_size(void __iomem *dfh_base, resource_size_t max)
+{
+	int size = 0;
+	u64 v, next;
+
+	if (!FIELD_GET(DFHv1_CSR_SIZE_GRP_HAS_PARAMS,
+		       readq(dfh_base + DFHv1_CSR_SIZE_GRP)))
+		return 0;
+
+	while (size + DFHv1_PARAM_HDR < max) {
+		v = readq(dfh_base + DFHv1_PARAM_HDR + size);
+
+		next = FIELD_GET(DFHv1_PARAM_HDR_NEXT_OFFSET, v);
+		if (!next)
+			return -EINVAL;
+
+		size += next * sizeof(u64);
+
+		if (FIELD_GET(DFHv1_PARAM_HDR_NEXT_EOP, v))
+			return size;
+	}
+
+	return -ENOENT;
+}
+
+/*
+ * 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,
+			resource_size_t ofst, resource_size_t size, u16 fid)
+{
+	struct dfl_feature_info *finfo;
+	resource_size_t start, end;
+	int dfh_psize = 0;
+	u8 revision = 0;
+	u64 v, addr_off;
+	u8 dfh_ver = 0;
+	int ret;
+
+	if (fid != FEATURE_ID_AFU) {
+		v = readq(binfo->ioaddr + ofst);
+		revision = FIELD_GET(DFH_REVISION, v);
+		dfh_ver = FIELD_GET(DFH_VERSION, v);
+		/* read feature size and id if inputs are invalid */
+		size = size ? size : feature_size(v);
+		fid = fid ? fid : feature_id(v);
+		if (dfh_ver == 1) {
+			dfh_psize = dfh_get_param_size(binfo->ioaddr + ofst, size);
+			if (dfh_psize < 0) {
+				dev_err(binfo->dev,
+					"failed to read size of DFHv1 parameters %d\n",
+					dfh_psize);
+				return dfh_psize;
+			}
+			dev_dbg(binfo->dev, "dfhv1_psize %d\n", dfh_psize);
+		}
+	}
+
+	if (binfo->len - ofst < size)
+		return -EINVAL;
+
+	finfo = kzalloc(struct_size(finfo, params, dfh_psize / sizeof(u64)), GFP_KERNEL);
+	if (!finfo)
+		return -ENOMEM;
+
+	memcpy_fromio(finfo->params, binfo->ioaddr + ofst + DFHv1_PARAM_HDR, dfh_psize);
+	finfo->param_size = dfh_psize;
+
+	finfo->fid = fid;
+	finfo->revision = revision;
+	finfo->dfh_version = dfh_ver;
+	if (dfh_ver == 1) {
+		v = readq(binfo->ioaddr + ofst + DFHv1_CSR_ADDR);
+		addr_off = FIELD_GET(DFHv1_CSR_ADDR_MASK, v);
+		if (FIELD_GET(DFHv1_CSR_ADDR_REL, v))
+			start = addr_off << 1;
+		else
+			start = binfo->start + ofst + addr_off;
+
+		v = readq(binfo->ioaddr + ofst + DFHv1_CSR_SIZE_GRP);
+		end = start + FIELD_GET(DFHv1_CSR_SIZE_GRP_SIZE, v) - 1;
+	} else {
+		start = binfo->start + ofst;
+		end = start + size - 1;
+	}
+	finfo->mmio_res.flags = IORESOURCE_MEM;
+	finfo->mmio_res.start = start;
+	finfo->mmio_res.end = end;
+
+	ret = parse_feature_irqs(binfo, ofst, finfo);
+	if (ret) {
+		kfree(finfo);
+		return ret;
+	}
+
+	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,
+				  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, ofst, size, FEATURE_ID_AFU);
+}
+
+#define is_feature_dev_detected(binfo) (!!(binfo)->feature_dev)
+
+static int parse_feature_afu(struct build_feature_devs_info *binfo,
+			     resource_size_t ofst)
+{
+	if (!is_feature_dev_detected(binfo)) {
+		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, ofst);
+	default:
+		dev_info(binfo->dev, "AFU belonging to FIU %s is not supported yet.\n",
+			 binfo->feature_dev->name);
+	}
+
+	return 0;
+}
+
+static int build_info_prepare(struct build_feature_devs_info *binfo,
+			      resource_size_t start, resource_size_t len)
+{
+	struct device *dev = binfo->dev;
+	void __iomem *ioaddr;
+
+	if (!devm_request_mem_region(dev, start, len, dev_name(dev))) {
+		dev_err(dev, "request region fail, start:%pa, len:%pa\n",
+			&start, &len);
+		return -EBUSY;
+	}
+
+	ioaddr = devm_ioremap(dev, start, len);
+	if (!ioaddr) {
+		dev_err(dev, "ioremap region fail, start:%pa, len:%pa\n",
+			&start, &len);
+		return -ENOMEM;
+	}
+
+	binfo->start = start;
+	binfo->len = len;
+	binfo->ioaddr = ioaddr;
+
+	return 0;
+}
+
+static void build_info_complete(struct build_feature_devs_info *binfo)
+{
+	devm_iounmap(binfo->dev, binfo->ioaddr);
+	devm_release_mem_region(binfo->dev, binfo->start, binfo->len);
+}
+
+static int parse_feature_fiu(struct build_feature_devs_info *binfo,
+			     resource_size_t ofst)
+{
+	int ret = 0;
+	u32 offset;
+	u16 id;
+	u64 v;
+
+	if (is_feature_dev_detected(binfo)) {
+		build_info_complete(binfo);
+
+		ret = build_info_commit_dev(binfo);
+		if (ret)
+			return ret;
+
+		ret = build_info_prepare(binfo, binfo->start + ofst,
+					 binfo->len - ofst);
+		if (ret)
+			return ret;
+	}
+
+	v = readq(binfo->ioaddr + 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));
+	if (ret)
+		return ret;
+
+	ret = create_feature_instance(binfo, 0, 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(binfo->ioaddr + NEXT_AFU);
+
+	offset = FIELD_GET(NEXT_AFU_NEXT_DFH_OFST, v);
+	if (offset)
+		return parse_feature_afu(binfo, 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,
+				 resource_size_t ofst)
+{
+	if (!is_feature_dev_detected(binfo)) {
+		dev_err(binfo->dev, "the private feature 0x%x does not belong to any AFU.\n",
+			feature_id(readq(binfo->ioaddr + ofst)));
+		return -EINVAL;
+	}
+
+	return create_feature_instance(binfo, ofst, 0, 0);
+}
+
+/**
+ * parse_feature - parse a feature on given device feature list
+ *
+ * @binfo: build feature devices information.
+ * @ofst: offset to current FIU header
+ */
+static int parse_feature(struct build_feature_devs_info *binfo,
+			 resource_size_t ofst)
+{
+	u64 v;
+	u32 type;
+
+	v = readq(binfo->ioaddr + ofst + DFH);
+	type = FIELD_GET(DFH_TYPE, v);
+
+	switch (type) {
+	case DFH_TYPE_AFU:
+		return parse_feature_afu(binfo, ofst);
+	case DFH_TYPE_PRIVATE:
+		return parse_feature_private(binfo, ofst);
+	case DFH_TYPE_FIU:
+		return parse_feature_fiu(binfo, 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,
+			      resource_size_t start, resource_size_t len)
+{
+	resource_size_t end = start + len;
+	int ret = 0;
+	u32 ofst = 0;
+	u64 v;
+
+	ret = build_info_prepare(binfo, start, len);
+	if (ret)
+		return ret;
+
+	/* 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, start - binfo->start);
+		if (ret)
+			return ret;
+
+		v = readq(binfo->ioaddr + start - binfo->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 */
+	build_info_complete(binfo);
+
+	if (is_feature_dev_detected(binfo))
+		ret = build_info_commit_dev(binfo);
+
+	return ret;
+}
+
+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);
+	}
+
+	/* remove irq table */
+	if (info->irq_table)
+		devm_kfree(dev, info->irq_table);
+
+	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.
+ *
+ * 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)
+{
+	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;
+
+	list_add_tail(&dfl->node, &info->dfls);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_enum_info_add_dfl);
+
+/**
+ * dfl_fpga_enum_info_add_irq - add irq table to enum info
+ *
+ * @info: ptr to dfl_fpga_enum_info
+ * @nr_irqs: number of irqs of the DFL fpga device to be enumerated.
+ * @irq_table: Linux IRQ numbers for all irqs, indexed by local irq index of
+ *	       this device.
+ *
+ * One FPGA device may have several interrupts. This function adds irq
+ * information of the DFL fpga device to enum info for next step enumeration.
+ * This function should be called before dfl_fpga_feature_devs_enumerate().
+ * As we only support one irq domain for all DFLs in the same enum info, adding
+ * irq table a second time for the same enum info will return error.
+ *
+ * If we need to enumerate DFLs which belong to different irq domains, we
+ * should fill more enum info and enumerate them one by one.
+ *
+ * Return: 0 on success, negative error code otherwise.
+ */
+int dfl_fpga_enum_info_add_irq(struct dfl_fpga_enum_info *info,
+			       unsigned int nr_irqs, int *irq_table)
+{
+	if (!nr_irqs || !irq_table)
+		return -EINVAL;
+
+	if (info->irq_table)
+		return -EEXIST;
+
+	info->irq_table = devm_kmemdup(info->dev, irq_table,
+				       sizeof(int) * nr_irqs, GFP_KERNEL);
+	if (!info->irq_table)
+		return -ENOMEM;
+
+	info->nr_irqs = nr_irqs;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_enum_info_add_irq);
+
+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->parent = info->dev;
+	mutex_init(&cdev->lock);
+	INIT_LIST_HEAD(&cdev->port_dev_list);
+
+	cdev->region = fpga_region_register(info->dev, NULL, NULL);
+	if (IS_ERR(cdev->region)) {
+		ret = PTR_ERR(cdev->region);
+		goto free_cdev_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;
+
+	binfo->nr_irqs = info->nr_irqs;
+	if (info->nr_irqs)
+		binfo->irq_table = info->irq_table;
+
+	/*
+	 * 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->start, dfl->len);
+		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_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;
+
+	mutex_lock(&cdev->lock);
+	if (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;
+
+		/* remove released ports */
+		if (!device_is_registered(&port_dev->dev)) {
+			dfl_id_free(feature_dev_id_type(port_dev),
+				    port_dev->id);
+			platform_device_put(port_dev);
+		}
+
+		list_del(&pdata->node);
+		put_device(&port_dev->dev);
+	}
+	mutex_unlock(&cdev->lock);
+
+	remove_feature_devs(cdev);
+
+	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;
+
+	ret = bus_register(&dfl_bus_type);
+	if (ret)
+		return ret;
+
+	dfl_ids_init();
+
+	ret = dfl_chardev_init();
+	if (ret) {
+		dfl_ids_destroy();
+		bus_unregister(&dfl_bus_type);
+	}
+
+	return ret;
+}
+
+/**
+ * dfl_fpga_cdev_release_port - release a port platform device
+ *
+ * @cdev: parent container device.
+ * @port_id: id of the port platform device.
+ *
+ * This function allows user to release a port platform device. This is a
+ * mandatory step before turn a port from PF into VF for SRIOV support.
+ *
+ * Return: 0 on success, negative error code otherwise.
+ */
+int dfl_fpga_cdev_release_port(struct dfl_fpga_cdev *cdev, int port_id)
+{
+	struct dfl_feature_platform_data *pdata;
+	struct platform_device *port_pdev;
+	int ret = -ENODEV;
+
+	mutex_lock(&cdev->lock);
+	port_pdev = __dfl_fpga_cdev_find_port(cdev, &port_id,
+					      dfl_fpga_check_port_id);
+	if (!port_pdev)
+		goto unlock_exit;
+
+	if (!device_is_registered(&port_pdev->dev)) {
+		ret = -EBUSY;
+		goto put_dev_exit;
+	}
+
+	pdata = dev_get_platdata(&port_pdev->dev);
+
+	mutex_lock(&pdata->lock);
+	ret = dfl_feature_dev_use_begin(pdata, true);
+	mutex_unlock(&pdata->lock);
+	if (ret)
+		goto put_dev_exit;
+
+	platform_device_del(port_pdev);
+	cdev->released_port_num++;
+put_dev_exit:
+	put_device(&port_pdev->dev);
+unlock_exit:
+	mutex_unlock(&cdev->lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_cdev_release_port);
+
+/**
+ * dfl_fpga_cdev_assign_port - assign a port platform device back
+ *
+ * @cdev: parent container device.
+ * @port_id: id of the port platform device.
+ *
+ * This function allows user to assign a port platform device back. This is
+ * a mandatory step after disable SRIOV support.
+ *
+ * Return: 0 on success, negative error code otherwise.
+ */
+int dfl_fpga_cdev_assign_port(struct dfl_fpga_cdev *cdev, int port_id)
+{
+	struct dfl_feature_platform_data *pdata;
+	struct platform_device *port_pdev;
+	int ret = -ENODEV;
+
+	mutex_lock(&cdev->lock);
+	port_pdev = __dfl_fpga_cdev_find_port(cdev, &port_id,
+					      dfl_fpga_check_port_id);
+	if (!port_pdev)
+		goto unlock_exit;
+
+	if (device_is_registered(&port_pdev->dev)) {
+		ret = -EBUSY;
+		goto put_dev_exit;
+	}
+
+	ret = platform_device_add(port_pdev);
+	if (ret)
+		goto put_dev_exit;
+
+	pdata = dev_get_platdata(&port_pdev->dev);
+
+	mutex_lock(&pdata->lock);
+	dfl_feature_dev_use_end(pdata);
+	mutex_unlock(&pdata->lock);
+
+	cdev->released_port_num--;
+put_dev_exit:
+	put_device(&port_pdev->dev);
+unlock_exit:
+	mutex_unlock(&cdev->lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_cdev_assign_port);
+
+static void config_port_access_mode(struct device *fme_dev, int port_id,
+				    bool is_vf)
+{
+	void __iomem *base;
+	u64 v;
+
+	base = dfl_get_feature_ioaddr_by_id(fme_dev, FME_FEATURE_ID_HEADER);
+
+	v = readq(base + FME_HDR_PORT_OFST(port_id));
+
+	v &= ~FME_PORT_OFST_ACC_CTRL;
+	v |= FIELD_PREP(FME_PORT_OFST_ACC_CTRL,
+			is_vf ? FME_PORT_OFST_ACC_VF : FME_PORT_OFST_ACC_PF);
+
+	writeq(v, base + FME_HDR_PORT_OFST(port_id));
+}
+
+#define config_port_vf_mode(dev, id) config_port_access_mode(dev, id, true)
+#define config_port_pf_mode(dev, id) config_port_access_mode(dev, id, false)
+
+/**
+ * dfl_fpga_cdev_config_ports_pf - configure ports to PF access mode
+ *
+ * @cdev: parent container device.
+ *
+ * This function is needed in sriov configuration routine. It could be used to
+ * configure the all released ports from VF access mode to PF.
+ */
+void dfl_fpga_cdev_config_ports_pf(struct dfl_fpga_cdev *cdev)
+{
+	struct dfl_feature_platform_data *pdata;
+
+	mutex_lock(&cdev->lock);
+	list_for_each_entry(pdata, &cdev->port_dev_list, node) {
+		if (device_is_registered(&pdata->dev->dev))
+			continue;
+
+		config_port_pf_mode(cdev->fme_dev, pdata->id);
+	}
+	mutex_unlock(&cdev->lock);
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_cdev_config_ports_pf);
+
+/**
+ * dfl_fpga_cdev_config_ports_vf - configure ports to VF access mode
+ *
+ * @cdev: parent container device.
+ * @num_vfs: VF device number.
+ *
+ * This function is needed in sriov configuration routine. It could be used to
+ * configure the released ports from PF access mode to VF.
+ *
+ * Return: 0 on success, negative error code otherwise.
+ */
+int dfl_fpga_cdev_config_ports_vf(struct dfl_fpga_cdev *cdev, int num_vfs)
+{
+	struct dfl_feature_platform_data *pdata;
+	int ret = 0;
+
+	mutex_lock(&cdev->lock);
+	/*
+	 * can't turn multiple ports into 1 VF device, only 1 port for 1 VF
+	 * device, so if released port number doesn't match VF device number,
+	 * then reject the request with -EINVAL error code.
+	 */
+	if (cdev->released_port_num != num_vfs) {
+		ret = -EINVAL;
+		goto done;
+	}
+
+	list_for_each_entry(pdata, &cdev->port_dev_list, node) {
+		if (device_is_registered(&pdata->dev->dev))
+			continue;
+
+		config_port_vf_mode(cdev->fme_dev, pdata->id);
+	}
+done:
+	mutex_unlock(&cdev->lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_cdev_config_ports_vf);
+
+static irqreturn_t dfl_irq_handler(int irq, void *arg)
+{
+	struct eventfd_ctx *trigger = arg;
+
+	eventfd_signal(trigger, 1);
+	return IRQ_HANDLED;
+}
+
+static int do_set_irq_trigger(struct dfl_feature *feature, unsigned int idx,
+			      int fd)
+{
+	struct platform_device *pdev = feature->dev;
+	struct eventfd_ctx *trigger;
+	int irq, ret;
+
+	irq = feature->irq_ctx[idx].irq;
+
+	if (feature->irq_ctx[idx].trigger) {
+		free_irq(irq, feature->irq_ctx[idx].trigger);
+		kfree(feature->irq_ctx[idx].name);
+		eventfd_ctx_put(feature->irq_ctx[idx].trigger);
+		feature->irq_ctx[idx].trigger = NULL;
+	}
+
+	if (fd < 0)
+		return 0;
+
+	feature->irq_ctx[idx].name =
+		kasprintf(GFP_KERNEL, "fpga-irq[%u](%s-%x)", idx,
+			  dev_name(&pdev->dev), feature->id);
+	if (!feature->irq_ctx[idx].name)
+		return -ENOMEM;
+
+	trigger = eventfd_ctx_fdget(fd);
+	if (IS_ERR(trigger)) {
+		ret = PTR_ERR(trigger);
+		goto free_name;
+	}
+
+	ret = request_irq(irq, dfl_irq_handler, 0,
+			  feature->irq_ctx[idx].name, trigger);
+	if (!ret) {
+		feature->irq_ctx[idx].trigger = trigger;
+		return ret;
+	}
+
+	eventfd_ctx_put(trigger);
+free_name:
+	kfree(feature->irq_ctx[idx].name);
+
+	return ret;
+}
+
+/**
+ * dfl_fpga_set_irq_triggers - set eventfd triggers for dfl feature interrupts
+ *
+ * @feature: dfl sub feature.
+ * @start: start of irq index in this dfl sub feature.
+ * @count: number of irqs.
+ * @fds: eventfds to bind with irqs. unbind related irq if fds[n] is negative.
+ *	 unbind "count" specified number of irqs if fds ptr is NULL.
+ *
+ * Bind given eventfds with irqs in this dfl sub feature. Unbind related irq if
+ * fds[n] is negative. Unbind "count" specified number of irqs if fds ptr is
+ * NULL.
+ *
+ * Return: 0 on success, negative error code otherwise.
+ */
+int dfl_fpga_set_irq_triggers(struct dfl_feature *feature, unsigned int start,
+			      unsigned int count, int32_t *fds)
+{
+	unsigned int i;
+	int ret = 0;
+
+	/* overflow */
+	if (unlikely(start + count < start))
+		return -EINVAL;
+
+	/* exceeds nr_irqs */
+	if (start + count > feature->nr_irqs)
+		return -EINVAL;
+
+	for (i = 0; i < count; i++) {
+		int fd = fds ? fds[i] : -1;
+
+		ret = do_set_irq_trigger(feature, start + i, fd);
+		if (ret) {
+			while (i--)
+				do_set_irq_trigger(feature, start + i, -1);
+			break;
+		}
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dfl_fpga_set_irq_triggers);
+
+/**
+ * dfl_feature_ioctl_get_num_irqs - dfl feature _GET_IRQ_NUM ioctl interface.
+ * @pdev: the feature device which has the sub feature
+ * @feature: the dfl sub feature
+ * @arg: ioctl argument
+ *
+ * Return: 0 on success, negative error code otherwise.
+ */
+long dfl_feature_ioctl_get_num_irqs(struct platform_device *pdev,
+				    struct dfl_feature *feature,
+				    unsigned long arg)
+{
+	return put_user(feature->nr_irqs, (__u32 __user *)arg);
+}
+EXPORT_SYMBOL_GPL(dfl_feature_ioctl_get_num_irqs);
+
+/**
+ * dfl_feature_ioctl_set_irq - dfl feature _SET_IRQ ioctl interface.
+ * @pdev: the feature device which has the sub feature
+ * @feature: the dfl sub feature
+ * @arg: ioctl argument
+ *
+ * Return: 0 on success, negative error code otherwise.
+ */
+long dfl_feature_ioctl_set_irq(struct platform_device *pdev,
+			       struct dfl_feature *feature,
+			       unsigned long arg)
+{
+	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
+	struct dfl_fpga_irq_set hdr;
+	s32 *fds;
+	long ret;
+
+	if (!feature->nr_irqs)
+		return -ENOENT;
+
+	if (copy_from_user(&hdr, (void __user *)arg, sizeof(hdr)))
+		return -EFAULT;
+
+	if (!hdr.count || (hdr.start + hdr.count > feature->nr_irqs) ||
+	    (hdr.start + hdr.count < hdr.start))
+		return -EINVAL;
+
+	fds = memdup_user((void __user *)(arg + sizeof(hdr)),
+			  array_size(hdr.count, sizeof(s32)));
+	if (IS_ERR(fds))
+		return PTR_ERR(fds);
+
+	mutex_lock(&pdata->lock);
+	ret = dfl_fpga_set_irq_triggers(feature, hdr.start, hdr.count, fds);
+	mutex_unlock(&pdata->lock);
+
+	kfree(fds);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dfl_feature_ioctl_set_irq);
+
+static void __exit dfl_fpga_exit(void)
+{
+	dfl_chardev_uinit();
+	dfl_ids_destroy();
+	bus_unregister(&dfl_bus_type);
+}
+
+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");