// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2023, Qualcomm Innovation Center, Inc. All rights reserved.
 */
#include <linux/debugfs.h>
#include <linux/interconnect.h>
#include <linux/platform_device.h>

#include "internal.h"

/*
 * This can be dangerous, therefore don't provide any real compile time
 * configuration option for this feature.
 * People who want to use this will need to modify the source code directly.
 */
#undef INTERCONNECT_ALLOW_WRITE_DEBUGFS

#if defined(INTERCONNECT_ALLOW_WRITE_DEBUGFS) && defined(CONFIG_DEBUG_FS)

static LIST_HEAD(debugfs_paths);
static DEFINE_MUTEX(debugfs_lock);

static struct platform_device *pdev;
static struct icc_path *cur_path;

static char *src_node;
static char *dst_node;
static u32 avg_bw;
static u32 peak_bw;
static u32 tag;

struct debugfs_path {
        const char *src;
        const char *dst;
        struct icc_path *path;
        struct list_head list;
};

static struct icc_path *get_path(const char *src, const char *dst)
{
        struct debugfs_path *path;

        list_for_each_entry(path, &debugfs_paths, list) {
                if (!strcmp(path->src, src) && !strcmp(path->dst, dst))
                        return path->path;
        }

        return NULL;
}

static int icc_get_set(void *data, u64 val)
{
        struct debugfs_path *debugfs_path;
        char *src, *dst;
        int ret = 0;

        mutex_lock(&debugfs_lock);

        rcu_read_lock();
        src = rcu_dereference(src_node);
        dst = rcu_dereference(dst_node);

        /*
         * If we've already looked up a path, then use the existing one instead
         * of calling icc_get() again. This allows for updating previous BW
         * votes when "get" is written to multiple times for multiple paths.
         */
        cur_path = get_path(src, dst);
        if (cur_path) {
                rcu_read_unlock();
                goto out;
        }

        src = kstrdup(src, GFP_ATOMIC);
        dst = kstrdup(dst, GFP_ATOMIC);
        rcu_read_unlock();

        if (!src || !dst) {
                ret = -ENOMEM;
                goto err_free;
        }

        cur_path = icc_get(&pdev->dev, src, dst);
        if (IS_ERR(cur_path)) {
                ret = PTR_ERR(cur_path);
                goto err_free;
        }

        debugfs_path = kzalloc_obj(*debugfs_path);
        if (!debugfs_path) {
                ret = -ENOMEM;
                goto err_put;
        }

        debugfs_path->path = cur_path;
        debugfs_path->src = src;
        debugfs_path->dst = dst;
        list_add_tail(&debugfs_path->list, &debugfs_paths);

        goto out;

err_put:
        icc_put(cur_path);
err_free:
        kfree(src);
        kfree(dst);
out:
        mutex_unlock(&debugfs_lock);
        return ret;
}

DEFINE_DEBUGFS_ATTRIBUTE(icc_get_fops, NULL, icc_get_set, "%llu\n");

static int icc_commit_set(void *data, u64 val)
{
        int ret;

        mutex_lock(&debugfs_lock);

        if (!cur_path) {
                ret = -EINVAL;
                goto out;
        }

        if (IS_ERR(cur_path)) {
                ret = PTR_ERR(cur_path);
                goto out;
        }

        icc_set_tag(cur_path, tag);
        ret = icc_set_bw(cur_path, avg_bw, peak_bw);
out:
        mutex_unlock(&debugfs_lock);
        return ret;
}

DEFINE_DEBUGFS_ATTRIBUTE(icc_commit_fops, NULL, icc_commit_set, "%llu\n");

int icc_debugfs_client_init(struct dentry *icc_dir)
{
        struct dentry *client_dir;
        int ret;

        pdev = platform_device_alloc("icc-debugfs-client", PLATFORM_DEVID_NONE);

        ret = platform_device_add(pdev);
        if (ret) {
                pr_err("%s: failed to add platform device: %d\n", __func__, ret);
                platform_device_put(pdev);
                return ret;
        }

        src_node = devm_kstrdup(&pdev->dev, "", GFP_KERNEL);
        dst_node = devm_kstrdup(&pdev->dev, "", GFP_KERNEL);
        if (!src_node || !dst_node)
                return -ENOMEM;

        client_dir = debugfs_create_dir("test_client", icc_dir);

        debugfs_create_str("src_node", 0600, client_dir, &src_node);
        debugfs_create_str("dst_node", 0600, client_dir, &dst_node);
        debugfs_create_file("get", 0200, client_dir, NULL, &icc_get_fops);
        debugfs_create_u32("avg_bw", 0600, client_dir, &avg_bw);
        debugfs_create_u32("peak_bw", 0600, client_dir, &peak_bw);
        debugfs_create_u32("tag", 0600, client_dir, &tag);
        debugfs_create_file("commit", 0200, client_dir, NULL, &icc_commit_fops);

        return 0;
}

#else

int icc_debugfs_client_init(struct dentry *icc_dir)
{
        return 0;
}

#endif