// SPDX-License-Identifier: GPL-2.0
/*
 * Greybus operations
 *
 * Copyright 2015-2016 Google Inc.
 */

#include <linux/string.h>
#include <linux/sysfs.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/idr.h>

#include "audio_manager.h"
#include "audio_manager_private.h"

static struct kset *manager_kset;

static LIST_HEAD(modules_list);
static DECLARE_RWSEM(modules_rwsem);
static DEFINE_IDA(module_id);

/* helpers */
static struct gb_audio_manager_module *gb_audio_manager_get_locked(int id)
{
        struct gb_audio_manager_module *module;

        if (id < 0)
                return NULL;

        list_for_each_entry(module, &modules_list, list) {
                if (module->id == id)
                        return module;
        }

        return NULL;
}

/* public API */
int gb_audio_manager_add(struct gb_audio_manager_module_descriptor *desc)
{
        struct gb_audio_manager_module *module;
        int id;
        int err;

        id = ida_alloc(&module_id, GFP_KERNEL);
        if (id < 0)
                return id;

        err = gb_audio_manager_module_create(&module, manager_kset,
                                             id, desc);
        if (err) {
                ida_free(&module_id, id);
                return err;
        }

        /* Add it to the list */
        down_write(&modules_rwsem);
        list_add_tail(&module->list, &modules_list);
        up_write(&modules_rwsem);

        return module->id;
}
EXPORT_SYMBOL_GPL(gb_audio_manager_add);

int gb_audio_manager_remove(int id)
{
        struct gb_audio_manager_module *module;

        down_write(&modules_rwsem);

        module = gb_audio_manager_get_locked(id);
        if (!module) {
                up_write(&modules_rwsem);
                return -EINVAL;
        }
        list_del(&module->list);
        kobject_put(&module->kobj);
        up_write(&modules_rwsem);
        ida_free(&module_id, id);
        return 0;
}
EXPORT_SYMBOL_GPL(gb_audio_manager_remove);

void gb_audio_manager_remove_all(void)
{
        struct gb_audio_manager_module *module, *next;
        int is_empty;

        down_write(&modules_rwsem);

        list_for_each_entry_safe(module, next, &modules_list, list) {
                list_del(&module->list);
                ida_free(&module_id, module->id);
                kobject_put(&module->kobj);
        }

        is_empty = list_empty(&modules_list);

        up_write(&modules_rwsem);

        if (!is_empty)
                pr_warn("Not all nodes were deleted\n");
}
EXPORT_SYMBOL_GPL(gb_audio_manager_remove_all);

void gb_audio_manager_put_module(struct gb_audio_manager_module *module)
{
        kobject_put(&module->kobj);
}
EXPORT_SYMBOL_GPL(gb_audio_manager_put_module);

int gb_audio_manager_dump_module(int id)
{
        struct gb_audio_manager_module *module;

        down_read(&modules_rwsem);
        module = gb_audio_manager_get_locked(id);
        up_read(&modules_rwsem);

        if (!module)
                return -EINVAL;

        gb_audio_manager_module_dump(module);
        return 0;
}
EXPORT_SYMBOL_GPL(gb_audio_manager_dump_module);

void gb_audio_manager_dump_all(void)
{
        struct gb_audio_manager_module *module;
        int count = 0;

        down_read(&modules_rwsem);
        list_for_each_entry(module, &modules_list, list) {
                gb_audio_manager_module_dump(module);
                count++;
        }
        up_read(&modules_rwsem);

        pr_info("Number of connected modules: %d\n", count);
}
EXPORT_SYMBOL_GPL(gb_audio_manager_dump_all);

/*
 * module init/deinit
 */
static int __init manager_init(void)
{
        manager_kset = kset_create_and_add(GB_AUDIO_MANAGER_NAME, NULL,
                                           kernel_kobj);
        if (!manager_kset)
                return -ENOMEM;

#ifdef GB_AUDIO_MANAGER_SYSFS
        gb_audio_manager_sysfs_init(&manager_kset->kobj);
#endif

        return 0;
}

static void __exit manager_exit(void)
{
        gb_audio_manager_remove_all();
        kset_unregister(manager_kset);
        ida_destroy(&module_id);
}

module_init(manager_init);
module_exit(manager_exit);

MODULE_DESCRIPTION("Greybus audio operations manager");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Svetlin Ankov <ankov_svetlin@projectara.com>");