// SPDX-License-Identifier: GPL-2.0-or-later

  /* Support for hardware buffer manager.
   *
   * Copyright (C) 2016 Marvell
   *
   * Gregory CLEMENT <gregory.clement@free-electrons.com>

   */
  #include <linux/kernel.h>
  #include <linux/printk.h>
  #include <linux/skbuff.h>
  #include <net/hwbm.h>
  
  void hwbm_buf_free(struct hwbm_pool *bm_pool, void *buf)
  {
  	if (likely(bm_pool->frag_size <= PAGE_SIZE))
  		skb_free_frag(buf);
  	else
  		kfree(buf);
  }
  EXPORT_SYMBOL_GPL(hwbm_buf_free);
  
  /* Refill processing for HW buffer management */
  int hwbm_pool_refill(struct hwbm_pool *bm_pool, gfp_t gfp)
  {
  	int frag_size = bm_pool->frag_size;
  	void *buf;
  
  	if (likely(frag_size <= PAGE_SIZE))
  		buf = netdev_alloc_frag(frag_size);
  	else
  		buf = kmalloc(frag_size, gfp);
  
  	if (!buf)
  		return -ENOMEM;
  
  	if (bm_pool->construct)
  		if (bm_pool->construct(bm_pool, buf)) {
  			hwbm_buf_free(bm_pool, buf);
  			return -ENOMEM;
  		}
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(hwbm_pool_refill);

  int hwbm_pool_add(struct hwbm_pool *bm_pool, unsigned int buf_num)

  {
  	int err, i;

  	mutex_lock(&bm_pool->buf_lock);

  	if (bm_pool->buf_num == bm_pool->size) {
  		pr_warn("pool already filled
  ");

  		mutex_unlock(&bm_pool->buf_lock);

  		return bm_pool->buf_num;
  	}
  
  	if (buf_num + bm_pool->buf_num > bm_pool->size) {
  		pr_warn("cannot allocate %d buffers for pool
  ",
  			buf_num);

  		mutex_unlock(&bm_pool->buf_lock);

  		return 0;
  	}
  
  	if ((buf_num + bm_pool->buf_num) < bm_pool->buf_num) {
  		pr_warn("Adding %d buffers to the %d current buffers will overflow
  ",
  			buf_num,  bm_pool->buf_num);

  		mutex_unlock(&bm_pool->buf_lock);

  		return 0;
  	}
  
  	for (i = 0; i < buf_num; i++) {

  		err = hwbm_pool_refill(bm_pool, GFP_KERNEL);

  		if (err < 0)
  			break;
  	}
  
  	/* Update BM driver with number of buffers added to pool */
  	bm_pool->buf_num += i;
  
  	pr_debug("hwpm pool: %d of %d buffers added
  ", i, buf_num);

  	mutex_unlock(&bm_pool->buf_lock);

  
  	return i;
  }
  EXPORT_SYMBOL_GPL(hwbm_pool_add);