// 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\n");
                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\n",
                        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\n",
                        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\n", i, buf_num);
        mutex_unlock(&bm_pool->buf_lock);

        return i;
}
EXPORT_SYMBOL_GPL(hwbm_pool_add);