/*
 * Copyright (C) 2022 HiSilicon (Shanghai) Technologies CO., LIMITED.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/wait.h>
#include <linux/spinlock.h>
#include "hi_osal.h"
#include "securec.h"

#define FENCE_READY    1
#define FENCE_NOREADY  0
typedef struct osal_fence_ {
    int module_id;
    int fd;
    wait_queue_head_t queue;
    int condition;
    void *private;
    unsigned int private_size;
    unsigned int ref;
    struct osal_list_head node;
} osal_fence;

static int g_fd_no = 0; // 临时占用，一秒1000个，可使用49天

static DEFINE_SPINLOCK(lock);
static OSAL_LIST_HEAD(fence_list);

#define FENCE_PRIVATE_MAX_SIZE 0x100

void osal_fence_try_del(osal_fence *fence)
{
    if (fence->ref > 0) {
        return;
    }

    osal_list_del(&fence->node);

    if (fence->private != NULL) {
        kfree(fence->private);
        fence->private = NULL;
    }

    kfree(fence);
}

osal_fence *osal_fence_find_node(int fd, struct osal_list_head *list)
{
    osal_fence *fence_node = NULL;

    osal_list_for_each_entry(fence_node, list, node) {
        if (fence_node->fd == fd) {
            return fence_node;
        }
    }

    return NULL;
}

int osal_fence_create(unsigned int module_id, int *fd, unsigned int private_size)
{
    osal_fence *fence_node = NULL;
    unsigned long flags;
    errno_t err;

    if (fd == NULL) {
        return -1;
    }

    if (private_size > FENCE_PRIVATE_MAX_SIZE) {
        return -1;
    }

    fence_node = kmalloc(sizeof(osal_fence), GFP_KERNEL);
    if (fence_node == NULL) {
        return -1;
    }

    err = memset_s(fence_node, sizeof(osal_fence), 0, sizeof(osal_fence));
    if (err != EOK) {
        kfree(fence_node);
        return -1;
    }

    fence_node->private_size = private_size;
    if (private_size != 0) {
        fence_node->private = kmalloc(private_size, GFP_KERNEL);
        if (fence_node->private == NULL) {
            kfree(fence_node);
            return -1;
        }
    } else {
        fence_node->private = NULL;
    }

    fence_node->module_id = module_id;
    fence_node->condition = FENCE_NOREADY;
    fence_node->ref = 1;

    init_waitqueue_head(&fence_node->queue);

    spin_lock_irqsave(&lock, flags);
    fence_node->fd = g_fd_no;
    g_fd_no++;

    osal_list_add_tail(&(fence_node->node), &fence_list);

    *fd = fence_node->fd;

    spin_unlock_irqrestore(&lock, flags);

    return 0;
}
EXPORT_SYMBOL(osal_fence_create);

int osal_fence_destroy(unsigned int module_id, int fd)
{
    osal_fence *fence_node = NULL;
    unsigned long flags;

    spin_lock_irqsave(&lock, flags);

    fence_node = osal_fence_find_node(fd, &fence_list);
    if (fence_node == NULL) {
        spin_unlock_irqrestore(&lock, flags);
        return -1;
    }

    fence_node->ref--;

    osal_fence_try_del(fence_node);

    spin_unlock_irqrestore(&lock, flags);

    return 0;
}
EXPORT_SYMBOL(osal_fence_destroy);

int osal_fence_acquire_private(unsigned int module_id, int fd, void **private)
{
    osal_fence *fence_node = NULL;
    unsigned long flags;

    if (private == NULL) {
        return -1;
    }

    spin_lock_irqsave(&lock, flags);

    fence_node = osal_fence_find_node(fd, &fence_list);
    if (fence_node == NULL) {
        spin_unlock_irqrestore(&lock, flags);
        return -1;
    }

    fence_node->ref++;

    spin_unlock_irqrestore(&lock, flags);

    *private = fence_node->private;

    return 0;
}
EXPORT_SYMBOL(osal_fence_acquire_private);

int osal_fence_release_private(unsigned int module_id, int fd, void *private)
{
    osal_fence *fence_node = NULL;
    unsigned long flags;

    spin_lock_irqsave(&lock, flags);

    fence_node = osal_fence_find_node(fd, &fence_list);
    if (fence_node == NULL) {
        spin_unlock_irqrestore(&lock, flags);
        return -1;
    }

    fence_node->ref--;

    osal_fence_try_del(fence_node);

    spin_unlock_irqrestore(&lock, flags);

    return 0;
}
EXPORT_SYMBOL(osal_fence_release_private);

int osal_fence_signal(int fd)
{
    osal_fence *fence_node = NULL;
    unsigned long flags;

    spin_lock_irqsave(&lock, flags);

    fence_node = osal_fence_find_node(fd, &fence_list);
    if (fence_node == NULL) {
        spin_unlock_irqrestore(&lock, flags);
        return -1;
    }

    fence_node->condition = FENCE_READY;

    wake_up(&fence_node->queue);

    spin_unlock_irqrestore(&lock, flags);

    return 0;
}
EXPORT_SYMBOL(osal_fence_signal);

int osal_fence_wait(int fd, unsigned int ms)
{
    osal_fence *fence_node = NULL;
    long timeout;
    unsigned long flags;

    spin_lock_irqsave(&lock, flags);

    fence_node = osal_fence_find_node(fd, &fence_list);
    if (fence_node == NULL) {
        spin_unlock_irqrestore(&lock, flags);
        return -1;
    }

    fence_node->ref++;

    spin_unlock_irqrestore(&lock, flags);

    timeout = wait_event_interruptible_timeout(fence_node->queue,
                                               (fence_node->condition == FENCE_READY),
                                               msecs_to_jiffies(ms));
    spin_lock_irqsave(&lock, flags);
    fence_node->ref--;
    osal_fence_try_del(fence_node);
    spin_unlock_irqrestore(&lock, flags);

    if (timeout == 0) {
        return -1;
    }

    return 0;
}
EXPORT_SYMBOL(osal_fence_wait);

int osal_fence_trywait(int fd)
{
    osal_fence *fence_node = NULL;
    unsigned long flags;

    spin_lock_irqsave(&lock, flags);

    fence_node = osal_fence_find_node(fd, &fence_list);
    if (fence_node == NULL) {
        spin_unlock_irqrestore(&lock, flags);
        return -1;
    }

    if (fence_node->condition == FENCE_READY) {
        spin_unlock_irqrestore(&lock, flags);
        return 0;
    }

    spin_unlock_irqrestore(&lock, flags);

    return -1; // not ready
}
EXPORT_SYMBOL(osal_fence_trywait);