// SPDX-License-Identifier: GPL-2.0
/*
 * Software nodes for the firmware node framework.
 *
 * Copyright (C) 2018, Intel Corporation
 * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
 */

#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/property.h>
#include <linux/slab.h>

struct swnode {
        int id;
        struct kobject kobj;
        struct fwnode_handle fwnode;
        const struct software_node *node;

        /* hierarchy */
        struct ida child_ids;
        struct list_head entry;
        struct list_head children;
        struct swnode *parent;

        unsigned int allocated:1;
};

static DEFINE_IDA(swnode_root_ids);
static struct kset *swnode_kset;

#define kobj_to_swnode(_kobj_) container_of(_kobj_, struct swnode, kobj)

static const struct fwnode_operations software_node_ops;

bool is_software_node(const struct fwnode_handle *fwnode)
{
        return !IS_ERR_OR_NULL(fwnode) && fwnode->ops == &software_node_ops;
}
EXPORT_SYMBOL_GPL(is_software_node);

#define to_swnode(__fwnode)                                             \
        ({                                                              \
                typeof(__fwnode) __to_swnode_fwnode = __fwnode;         \
                                                                        \
                is_software_node(__to_swnode_fwnode) ?                  \
                        container_of(__to_swnode_fwnode,                \
                                     struct swnode, fwnode) : NULL;     \
        })

static struct swnode *
software_node_to_swnode(const struct software_node *node)
{
        struct swnode *swnode = NULL;
        struct kobject *k;

        if (!node)
                return NULL;

        spin_lock(&swnode_kset->list_lock);

        list_for_each_entry(k, &swnode_kset->list, entry) {
                swnode = kobj_to_swnode(k);
                if (swnode->node == node)
                        break;
                swnode = NULL;
        }

        spin_unlock(&swnode_kset->list_lock);

        return swnode;
}

const struct software_node *to_software_node(const struct fwnode_handle *fwnode)
{
        const struct swnode *swnode = to_swnode(fwnode);

        return swnode ? swnode->node : NULL;
}
EXPORT_SYMBOL_GPL(to_software_node);

struct fwnode_handle *software_node_fwnode(const struct software_node *node)
{
        struct swnode *swnode = software_node_to_swnode(node);

        return swnode ? &swnode->fwnode : NULL;
}
EXPORT_SYMBOL_GPL(software_node_fwnode);

/* -------------------------------------------------------------------------- */
/* property_entry processing */

static const struct property_entry *
property_entry_get(const struct property_entry *prop, const char *name)
{
        if (!prop)
                return NULL;

        for (; prop->name; prop++)
                if (!strcmp(name, prop->name))
                        return prop;

        return NULL;
}

static const void *property_get_pointer(const struct property_entry *prop)
{
        if (!prop->length)
                return NULL;

        return prop->is_inline ? &prop->value : prop->pointer;
}

static const void *property_entry_find(const struct property_entry *props,
                                       const char *propname, size_t length)
{
        const struct property_entry *prop;
        const void *pointer;

        prop = property_entry_get(props, propname);
        if (!prop)
                return ERR_PTR(-EINVAL);
        pointer = property_get_pointer(prop);
        if (!pointer)
                return ERR_PTR(-ENODATA);
        if (length > prop->length)
                return ERR_PTR(-EOVERFLOW);
        return pointer;
}

static int
property_entry_count_elems_of_size(const struct property_entry *props,
                                   const char *propname, size_t length)
{
        const struct property_entry *prop;

        prop = property_entry_get(props, propname);
        if (!prop)
                return -EINVAL;

        return prop->length / length;
}

static int property_entry_read_int_array(const struct property_entry *props,
                                         const char *name,
                                         unsigned int elem_size, void *val,
                                         size_t nval)
{
        const void *pointer;
        size_t length;

        if (!val)
                return property_entry_count_elems_of_size(props, name,
                                                          elem_size);

        if (!is_power_of_2(elem_size) || elem_size > sizeof(u64))
                return -ENXIO;

        length = nval * elem_size;

        pointer = property_entry_find(props, name, length);
        if (IS_ERR(pointer))
                return PTR_ERR(pointer);

        memcpy(val, pointer, length);
        return 0;
}

static int property_entry_read_string_array(const struct property_entry *props,
                                            const char *propname,
                                            const char **strings, size_t nval)
{
        const void *pointer;
        size_t length;
        int array_len;

        /* Find out the array length. */
        array_len = property_entry_count_elems_of_size(props, propname,
                                                       sizeof(const char *));
        if (array_len < 0)
                return array_len;

        /* Return how many there are if strings is NULL. */
        if (!strings)
                return array_len;

        array_len = min_t(size_t, nval, array_len);
        length = array_len * sizeof(*strings);

        pointer = property_entry_find(props, propname, length);
        if (IS_ERR(pointer))
                return PTR_ERR(pointer);

        memcpy(strings, pointer, length);

        return array_len;
}

static void property_entry_free_data(const struct property_entry *p)
{
        const char * const *src_str;
        size_t i, nval;

        if (p->type == DEV_PROP_STRING) {
                src_str = property_get_pointer(p);
                nval = p->length / sizeof(*src_str);
                for (i = 0; i < nval; i++)
                        kfree(src_str[i]);
        }

        if (!p->is_inline)
                kfree(p->pointer);

        kfree(p->name);
}

static bool property_copy_string_array(const char **dst_ptr,
                                       const char * const *src_ptr,
                                       size_t nval)
{
        int i;

        for (i = 0; i < nval; i++) {
                dst_ptr[i] = kstrdup(src_ptr[i], GFP_KERNEL);
                if (!dst_ptr[i] && src_ptr[i]) {
                        while (--i >= 0)
                                kfree(dst_ptr[i]);
                        return false;
                }
        }

        return true;
}

static int property_entry_copy_data(struct property_entry *dst,
                                    const struct property_entry *src)
{
        const void *pointer = property_get_pointer(src);
        void *dst_ptr;
        size_t nval;

        /*
         * Properties with no data should not be marked as stored
         * out of line.
         */
        if (!src->is_inline && !src->length)
                return -ENODATA;

        /*
         * Reference properties are never stored inline as
         * they are too big.
         */
        if (src->type == DEV_PROP_REF && src->is_inline)
                return -EINVAL;

        if (src->length <= sizeof(dst->value)) {
                dst_ptr = &dst->value;
                dst->is_inline = true;
        } else {
                dst_ptr = kmalloc(src->length, GFP_KERNEL);
                if (!dst_ptr)
                        return -ENOMEM;
                dst->pointer = dst_ptr;
        }

        if (src->type == DEV_PROP_STRING) {
                nval = src->length / sizeof(const char *);
                if (!property_copy_string_array(dst_ptr, pointer, nval)) {
                        if (!dst->is_inline)
                                kfree(dst->pointer);
                        return -ENOMEM;
                }
        } else {
                memcpy(dst_ptr, pointer, src->length);
        }

        dst->length = src->length;
        dst->type = src->type;
        dst->name = kstrdup(src->name, GFP_KERNEL);
        if (!dst->name) {
                property_entry_free_data(dst);
                return -ENOMEM;
        }

        return 0;
}

/**
 * property_entries_dup - duplicate array of properties
 * @properties: array of properties to copy
 *
 * This function creates a deep copy of the given NULL-terminated array
 * of property entries.
 */
struct property_entry *
property_entries_dup(const struct property_entry *properties)
{
        struct property_entry *p;
        int i, n = 0;
        int ret;

        if (!properties)
                return NULL;

        while (properties[n].name)
                n++;

        p = kcalloc(n + 1, sizeof(*p), GFP_KERNEL);
        if (!p)
                return ERR_PTR(-ENOMEM);

        for (i = 0; i < n; i++) {
                ret = property_entry_copy_data(&p[i], &properties[i]);
                if (ret) {
                        while (--i >= 0)
                                property_entry_free_data(&p[i]);
                        kfree(p);
                        return ERR_PTR(ret);
                }
        }

        return p;
}
EXPORT_SYMBOL_GPL(property_entries_dup);

/**
 * property_entries_free - free previously allocated array of properties
 * @properties: array of properties to destroy
 *
 * This function frees given NULL-terminated array of property entries,
 * along with their data.
 */
void property_entries_free(const struct property_entry *properties)
{
        const struct property_entry *p;

        if (!properties)
                return;

        for (p = properties; p->name; p++)
                property_entry_free_data(p);

        kfree(properties);
}
EXPORT_SYMBOL_GPL(property_entries_free);

/* -------------------------------------------------------------------------- */
/* fwnode operations */

static struct fwnode_handle *software_node_get(struct fwnode_handle *fwnode)
{
        struct swnode *swnode = to_swnode(fwnode);

        kobject_get(&swnode->kobj);

        return &swnode->fwnode;
}

static void software_node_put(struct fwnode_handle *fwnode)
{
        struct swnode *swnode = to_swnode(fwnode);

        kobject_put(&swnode->kobj);
}

static bool software_node_property_present(const struct fwnode_handle *fwnode,
                                           const char *propname)
{
        struct swnode *swnode = to_swnode(fwnode);

        return !!property_entry_get(swnode->node->properties, propname);
}

static int software_node_read_int_array(const struct fwnode_handle *fwnode,
                                        const char *propname,
                                        unsigned int elem_size, void *val,
                                        size_t nval)
{
        struct swnode *swnode = to_swnode(fwnode);

        return property_entry_read_int_array(swnode->node->properties, propname,
                                             elem_size, val, nval);
}

static int software_node_read_string_array(const struct fwnode_handle *fwnode,
                                           const char *propname,
                                           const char **val, size_t nval)
{
        struct swnode *swnode = to_swnode(fwnode);

        return property_entry_read_string_array(swnode->node->properties,
                                                propname, val, nval);
}

static const char *
software_node_get_name(const struct fwnode_handle *fwnode)
{
        const struct swnode *swnode = to_swnode(fwnode);

        if (!swnode)
                return "(null)";

        return kobject_name(&swnode->kobj);
}

static const char *
software_node_get_name_prefix(const struct fwnode_handle *fwnode)
{
        struct fwnode_handle *parent;
        const char *prefix;

        parent = fwnode_get_parent(fwnode);
        if (!parent)
                return "";

        /* Figure out the prefix from the parents. */
        while (is_software_node(parent))
                parent = fwnode_get_next_parent(parent);

        prefix = fwnode_get_name_prefix(parent);
        fwnode_handle_put(parent);

        /* Guess something if prefix was NULL. */
        return prefix ?: "/";
}

static struct fwnode_handle *
software_node_get_parent(const struct fwnode_handle *fwnode)
{
        struct swnode *swnode = to_swnode(fwnode);

        if (!swnode || !swnode->parent)
                return NULL;

        return fwnode_handle_get(&swnode->parent->fwnode);
}

static struct fwnode_handle *
software_node_get_next_child(const struct fwnode_handle *fwnode,
                             struct fwnode_handle *child)
{
        struct swnode *p = to_swnode(fwnode);
        struct swnode *c = to_swnode(child);

        if (!p || list_empty(&p->children) ||
            (c && list_is_last(&c->entry, &p->children)))
                return NULL;

        if (c)
                c = list_next_entry(c, entry);
        else
                c = list_first_entry(&p->children, struct swnode, entry);
        return &c->fwnode;
}

static struct fwnode_handle *
software_node_get_named_child_node(const struct fwnode_handle *fwnode,
                                   const char *childname)
{
        struct swnode *swnode = to_swnode(fwnode);
        struct swnode *child;

        if (!swnode || list_empty(&swnode->children))
                return NULL;

        list_for_each_entry(child, &swnode->children, entry) {
                if (!strcmp(childname, kobject_name(&child->kobj))) {
                        kobject_get(&child->kobj);
                        return &child->fwnode;
                }
        }
        return NULL;
}

static int
software_node_get_reference_args(const struct fwnode_handle *fwnode,
                                 const char *propname, const char *nargs_prop,
                                 unsigned int nargs, unsigned int index,
                                 struct fwnode_reference_args *args)
{
        struct swnode *swnode = to_swnode(fwnode);
        const struct software_node_ref_args *ref_array;
        const struct software_node_ref_args *ref;
        const struct property_entry *prop;
        struct fwnode_handle *refnode;
        u32 nargs_prop_val;
        int error;
        int i;

        if (!swnode)
                return -ENOENT;

        prop = property_entry_get(swnode->node->properties, propname);
        if (!prop)
                return -ENOENT;

        if (prop->type != DEV_PROP_REF)
                return -EINVAL;

        /*
         * We expect that references are never stored inline, even
         * single ones, as they are too big.
         */
        if (prop->is_inline)
                return -EINVAL;

        if (index * sizeof(*ref) >= prop->length)
                return -ENOENT;

        ref_array = prop->pointer;
        ref = &ref_array[index];

        refnode = software_node_fwnode(ref->node);
        if (!refnode)
                return -ENOENT;

        if (nargs_prop) {
                error = property_entry_read_int_array(swnode->node->properties,
                                                      nargs_prop, sizeof(u32),
                                                      &nargs_prop_val, 1);
                if (error)
                        return error;

                nargs = nargs_prop_val;
        }

        if (nargs > NR_FWNODE_REFERENCE_ARGS)
                return -EINVAL;

        args->fwnode = software_node_get(refnode);
        args->nargs = nargs;

        for (i = 0; i < nargs; i++)
                args->args[i] = ref->args[i];

        return 0;
}

static const struct fwnode_operations software_node_ops = {
        .get = software_node_get,
        .put = software_node_put,
        .property_present = software_node_property_present,
        .property_read_int_array = software_node_read_int_array,
        .property_read_string_array = software_node_read_string_array,
        .get_name = software_node_get_name,
        .get_name_prefix = software_node_get_name_prefix,
        .get_parent = software_node_get_parent,
        .get_next_child_node = software_node_get_next_child,
        .get_named_child_node = software_node_get_named_child_node,
        .get_reference_args = software_node_get_reference_args
};

/* -------------------------------------------------------------------------- */

/**
 * software_node_find_by_name - Find software node by name
 * @parent: Parent of the software node
 * @name: Name of the software node
 *
 * The function will find a node that is child of @parent and that is named
 * @name. If no node is found, the function returns NULL.
 *
 * NOTE: you will need to drop the reference with fwnode_handle_put() after use.
 */
const struct software_node *
software_node_find_by_name(const struct software_node *parent, const char *name)
{
        struct swnode *swnode = NULL;
        struct kobject *k;

        if (!name)
                return NULL;

        spin_lock(&swnode_kset->list_lock);

        list_for_each_entry(k, &swnode_kset->list, entry) {
                swnode = kobj_to_swnode(k);
                if (parent == swnode->node->parent && swnode->node->name &&
                    !strcmp(name, swnode->node->name)) {
                        kobject_get(&swnode->kobj);
                        break;
                }
                swnode = NULL;
        }

        spin_unlock(&swnode_kset->list_lock);

        return swnode ? swnode->node : NULL;
}
EXPORT_SYMBOL_GPL(software_node_find_by_name);

static int
software_node_register_properties(struct software_node *node,
                                  const struct property_entry *properties)
{
        struct property_entry *props;

        props = property_entries_dup(properties);
        if (IS_ERR(props))
                return PTR_ERR(props);

        node->properties = props;

        return 0;
}

static void software_node_release(struct kobject *kobj)
{
        struct swnode *swnode = kobj_to_swnode(kobj);

        if (swnode->parent) {
                ida_simple_remove(&swnode->parent->child_ids, swnode->id);
                list_del(&swnode->entry);
        } else {
                ida_simple_remove(&swnode_root_ids, swnode->id);
        }

        if (swnode->allocated) {
                property_entries_free(swnode->node->properties);
                kfree(swnode->node);
        }
        ida_destroy(&swnode->child_ids);
        kfree(swnode);
}

static struct kobj_type software_node_type = {
        .release = software_node_release,
        .sysfs_ops = &kobj_sysfs_ops,
};

static struct fwnode_handle *
swnode_register(const struct software_node *node, struct swnode *parent,
                unsigned int allocated)
{
        struct swnode *swnode;
        int ret;

        swnode = kzalloc(sizeof(*swnode), GFP_KERNEL);
        if (!swnode) {
                ret = -ENOMEM;
                goto out_err;
        }

        ret = ida_simple_get(parent ? &parent->child_ids : &swnode_root_ids,
                             0, 0, GFP_KERNEL);
        if (ret < 0) {
                kfree(swnode);
                goto out_err;
        }

        swnode->id = ret;
        swnode->node = node;
        swnode->parent = parent;
        swnode->allocated = allocated;
        swnode->kobj.kset = swnode_kset;
        swnode->fwnode.ops = &software_node_ops;

        ida_init(&swnode->child_ids);
        INIT_LIST_HEAD(&swnode->entry);
        INIT_LIST_HEAD(&swnode->children);

        if (node->name)
                ret = kobject_init_and_add(&swnode->kobj, &software_node_type,
                                           parent ? &parent->kobj : NULL,
                                           "%s", node->name);
        else
                ret = kobject_init_and_add(&swnode->kobj, &software_node_type,
                                           parent ? &parent->kobj : NULL,
                                           "node%d", swnode->id);
        if (ret) {
                kobject_put(&swnode->kobj);
                return ERR_PTR(ret);
        }

        if (parent)
                list_add_tail(&swnode->entry, &parent->children);

        kobject_uevent(&swnode->kobj, KOBJ_ADD);
        return &swnode->fwnode;

out_err:
        if (allocated)
                property_entries_free(node->properties);
        return ERR_PTR(ret);
}

/**
 * software_node_register_nodes - Register an array of software nodes
 * @nodes: Zero terminated array of software nodes to be registered
 *
 * Register multiple software nodes at once.
 */
int software_node_register_nodes(const struct software_node *nodes)
{
        int ret;
        int i;

        for (i = 0; nodes[i].name; i++) {
                ret = software_node_register(&nodes[i]);
                if (ret) {
                        software_node_unregister_nodes(nodes);
                        return ret;
                }
        }

        return 0;
}
EXPORT_SYMBOL_GPL(software_node_register_nodes);

/**
 * software_node_unregister_nodes - Unregister an array of software nodes
 * @nodes: Zero terminated array of software nodes to be unregistered
 *
 * Unregister multiple software nodes at once.
 *
 * NOTE: Be careful using this call if the nodes had parent pointers set up in
 * them before registering.  If so, it is wiser to remove the nodes
 * individually, in the correct order (child before parent) instead of relying
 * on the sequential order of the list of nodes in the array.
 */
void software_node_unregister_nodes(const struct software_node *nodes)
{
        int i;

        for (i = 0; nodes[i].name; i++)
                software_node_unregister(&nodes[i]);
}
EXPORT_SYMBOL_GPL(software_node_unregister_nodes);

/**
 * software_node_register_node_group - Register a group of software nodes
 * @node_group: NULL terminated array of software node pointers to be registered
 *
 * Register multiple software nodes at once.
 */
int software_node_register_node_group(const struct software_node **node_group)
{
        unsigned int i;
        int ret;

        if (!node_group)
                return 0;

        for (i = 0; node_group[i]; i++) {
                ret = software_node_register(node_group[i]);
                if (ret) {
                        software_node_unregister_node_group(node_group);
                        return ret;
                }
        }

        return 0;
}
EXPORT_SYMBOL_GPL(software_node_register_node_group);

/**
 * software_node_unregister_node_group - Unregister a group of software nodes
 * @node_group: NULL terminated array of software node pointers to be unregistered
 *
 * Unregister multiple software nodes at once.
 */
void software_node_unregister_node_group(const struct software_node **node_group)
{
        unsigned int i;

        if (!node_group)
                return;

        for (i = 0; node_group[i]; i++)
                software_node_unregister(node_group[i]);
}
EXPORT_SYMBOL_GPL(software_node_unregister_node_group);

/**
 * software_node_register - Register static software node
 * @node: The software node to be registered
 */
int software_node_register(const struct software_node *node)
{
        struct swnode *parent = software_node_to_swnode(node->parent);

        if (software_node_to_swnode(node))
                return -EEXIST;

        return PTR_ERR_OR_ZERO(swnode_register(node, parent, 0));
}
EXPORT_SYMBOL_GPL(software_node_register);

/**
 * software_node_unregister - Unregister static software node
 * @node: The software node to be unregistered
 */
void software_node_unregister(const struct software_node *node)
{
        struct swnode *swnode;

        swnode = software_node_to_swnode(node);
        if (swnode)
                fwnode_remove_software_node(&swnode->fwnode);
}
EXPORT_SYMBOL_GPL(software_node_unregister);

struct fwnode_handle *
fwnode_create_software_node(const struct property_entry *properties,
                            const struct fwnode_handle *parent)
{
        struct software_node *node;
        struct swnode *p = NULL;
        int ret;

        if (parent) {
                if (IS_ERR(parent))
                        return ERR_CAST(parent);
                if (!is_software_node(parent))
                        return ERR_PTR(-EINVAL);
                p = to_swnode(parent);
        }

        node = kzalloc(sizeof(*node), GFP_KERNEL);
        if (!node)
                return ERR_PTR(-ENOMEM);

        ret = software_node_register_properties(node, properties);
        if (ret) {
                kfree(node);
                return ERR_PTR(ret);
        }

        node->parent = p ? p->node : NULL;

        return swnode_register(node, p, 1);
}
EXPORT_SYMBOL_GPL(fwnode_create_software_node);

void fwnode_remove_software_node(struct fwnode_handle *fwnode)
{
        struct swnode *swnode = to_swnode(fwnode);

        if (!swnode)
                return;

        kobject_put(&swnode->kobj);
}
EXPORT_SYMBOL_GPL(fwnode_remove_software_node);

int software_node_notify(struct device *dev, unsigned long action)
{
        struct fwnode_handle *fwnode = dev_fwnode(dev);
        struct swnode *swnode;
        int ret;

        if (!fwnode)
                return 0;

        if (!is_software_node(fwnode))
                fwnode = fwnode->secondary;
        if (!is_software_node(fwnode))
                return 0;

        swnode = to_swnode(fwnode);

        switch (action) {
        case KOBJ_ADD:
                ret = sysfs_create_link(&dev->kobj, &swnode->kobj,
                                        "software_node");
                if (ret)
                        break;

                ret = sysfs_create_link(&swnode->kobj, &dev->kobj,
                                        dev_name(dev));
                if (ret) {
                        sysfs_remove_link(&dev->kobj, "software_node");
                        break;
                }
                kobject_get(&swnode->kobj);
                break;
        case KOBJ_REMOVE:
                sysfs_remove_link(&swnode->kobj, dev_name(dev));
                sysfs_remove_link(&dev->kobj, "software_node");
                kobject_put(&swnode->kobj);
                break;
        default:
                break;
        }

        return 0;
}

static int __init software_node_init(void)
{
        swnode_kset = kset_create_and_add("software_nodes", NULL, kernel_kobj);
        if (!swnode_kset)
                return -ENOMEM;
        return 0;
}
postcore_initcall(software_node_init);

static void __exit software_node_exit(void)
{
        ida_destroy(&swnode_root_ids);
        kset_unregister(swnode_kset);
}
__exitcall(software_node_exit);