/*
 * Copyright (C) 2015 Masahiro Yamada <yamada.masahiro@socionext.com>
 *
 * Based on the original work in Linux by
 * Copyright (c) 2006  SUSE Linux Products GmbH
 * Copyright (c) 2006  Tejun Heo <teheo@suse.de>
 *
 * SPDX-License-Identifier:     GPL-2.0+
 */

#include <common.h>
#include <linux/compat.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <dm/device.h>
#include <dm/root.h>
#include <dm/util.h>

/**
 * struct devres - Bookkeeping info for managed device resource
 * @entry: List to associate this structure with a device
 * @release: Callback invoked when this resource is released
 * @probe: Flag to show when this resource was allocated
           (true = probe, false = bind)
 * @name: Name of release function
 * @size: Size of resource data
 * @data: Resource data
 */
struct devres {
        struct list_head                entry;
        dr_release_t                    release;
        bool                            probe;
#ifdef CONFIG_DEBUG_DEVRES
        const char                      *name;
        size_t                          size;
#endif
        unsigned long long              data[];
};

#ifdef CONFIG_DEBUG_DEVRES
static void set_node_dbginfo(struct devres *dr, const char *name, size_t size)
{
        dr->name = name;
        dr->size = size;
}

static void devres_log(struct udevice *dev, struct devres *dr,
                       const char *op)
{
        printf("%s: DEVRES %3s %p %s (%lu bytes)\n",
               dev->name, op, dr, dr->name, (unsigned long)dr->size);
}
#else /* CONFIG_DEBUG_DEVRES */
#define set_node_dbginfo(dr, n, s)      do {} while (0)
#define devres_log(dev, dr, op)         do {} while (0)
#endif

#if CONFIG_DEBUG_DEVRES
void *__devres_alloc(dr_release_t release, size_t size, gfp_t gfp,
                     const char *name)
#else
void *_devres_alloc(dr_release_t release, size_t size, gfp_t gfp)
#endif
{
        size_t tot_size = sizeof(struct devres) + size;
        struct devres *dr;

        dr = kmalloc(tot_size, gfp);
        if (unlikely(!dr))
                return NULL;

        INIT_LIST_HEAD(&dr->entry);
        dr->release = release;
        set_node_dbginfo(dr, name, size);

        return dr->data;
}

void devres_free(void *res)
{
        if (res) {
                struct devres *dr = container_of(res, struct devres, data);

                BUG_ON(!list_empty(&dr->entry));
                kfree(dr);
        }
}

void devres_add(struct udevice *dev, void *res)
{
        struct devres *dr = container_of(res, struct devres, data);

        devres_log(dev, dr, "ADD");
        BUG_ON(!list_empty(&dr->entry));
        dr->probe = dev->flags & DM_FLAG_BOUND ? true : false;
        list_add_tail(&dr->entry, &dev->devres_head);
}

void *devres_find(struct udevice *dev, dr_release_t release,
                  dr_match_t match, void *match_data)
{
        struct devres *dr;

        list_for_each_entry_reverse(dr, &dev->devres_head, entry) {
                if (dr->release != release)
                        continue;
                if (match && !match(dev, dr->data, match_data))
                        continue;
                return dr->data;
        }

        return NULL;
}

void *devres_get(struct udevice *dev, void *new_res,
                 dr_match_t match, void *match_data)
{
        struct devres *new_dr = container_of(new_res, struct devres, data);
        void *res;

        res = devres_find(dev, new_dr->release, match, match_data);
        if (!res) {
                devres_add(dev, new_res);
                res = new_res;
                new_res = NULL;
        }
        devres_free(new_res);

        return res;
}

void *devres_remove(struct udevice *dev, dr_release_t release,
                    dr_match_t match, void *match_data)
{
        void *res;

        res = devres_find(dev, release, match, match_data);
        if (res) {
                struct devres *dr = container_of(res, struct devres, data);

                list_del_init(&dr->entry);
                devres_log(dev, dr, "REM");
        }

        return res;
}

int devres_destroy(struct udevice *dev, dr_release_t release,
                   dr_match_t match, void *match_data)
{
        void *res;

        res = devres_remove(dev, release, match, match_data);
        if (unlikely(!res))
                return -ENOENT;

        devres_free(res);
        return 0;
}

int devres_release(struct udevice *dev, dr_release_t release,
                   dr_match_t match, void *match_data)
{
        void *res;

        res = devres_remove(dev, release, match, match_data);
        if (unlikely(!res))
                return -ENOENT;

        (*release)(dev, res);
        devres_free(res);
        return 0;
}

static void release_nodes(struct udevice *dev, struct list_head *head,
                          bool probe_only)
{
        struct devres *dr, *tmp;

        list_for_each_entry_safe_reverse(dr, tmp, head, entry)  {
                if (probe_only && !dr->probe)
                        break;
                devres_log(dev, dr, "REL");
                dr->release(dev, dr->data);
                list_del(&dr->entry);
                kfree(dr);
        }
}

void devres_release_probe(struct udevice *dev)
{
        release_nodes(dev, &dev->devres_head, true);
}

void devres_release_all(struct udevice *dev)
{
        release_nodes(dev, &dev->devres_head, false);
}

#ifdef CONFIG_DEBUG_DEVRES
static void dump_resources(struct udevice *dev, int depth)
{
        struct devres *dr;
        struct udevice *child;

        printf("- %s\n", dev->name);

        list_for_each_entry(dr, &dev->devres_head, entry)
                printf("    %p (%lu byte) %s  %s\n", dr,
                       (unsigned long)dr->size, dr->name,
                       dr->probe ? "PROBE" : "BIND");

        list_for_each_entry(child, &dev->child_head, sibling_node)
                dump_resources(child, depth + 1);
}

void dm_dump_devres(void)
{
        struct udevice *root;

        root = dm_root();
        if (root)
                dump_resources(root, 0);
}
#endif

/*
 * Managed kmalloc/kfree
 */
static void devm_kmalloc_release(struct udevice *dev, void *res)
{
        /* noop */
}

static int devm_kmalloc_match(struct udevice *dev, void *res, void *data)
{
        return res == data;
}

void *devm_kmalloc(struct udevice *dev, size_t size, gfp_t gfp)
{
        void *data;

        data = _devres_alloc(devm_kmalloc_release, size, gfp);
        if (unlikely(!data))
                return NULL;

        devres_add(dev, data);

        return data;
}

void devm_kfree(struct udevice *dev, void *p)
{
        int rc;

        rc = devres_destroy(dev, devm_kmalloc_release, devm_kmalloc_match, p);
        WARN_ON(rc);
}