// SPDX-License-Identifier: GPL-2.0-only
/*******************************************************************************
  Specialised functions for managing Ring mode

  Copyright(C) 2011  STMicroelectronics Ltd

  It defines all the functions used to handle the normal/enhanced
  descriptors in case of the DMA is configured to work in chained or
  in ring mode.


  Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>
*******************************************************************************/

#include "stmmac.h"

static int jumbo_frm(struct stmmac_tx_queue *tx_q, struct sk_buff *skb,
                     int csum)
{
        unsigned int nopaged_len = skb_headlen(skb);
        struct stmmac_priv *priv = tx_q->priv_data;
        unsigned int entry = tx_q->cur_tx;
        unsigned int bmax, len, des2;
        struct dma_desc *desc;

        if (priv->extend_desc)
                desc = (struct dma_desc *)(tx_q->dma_etx + entry);
        else
                desc = tx_q->dma_tx + entry;

        if (priv->plat->enh_desc)
                bmax = BUF_SIZE_8KiB;
        else
                bmax = BUF_SIZE_2KiB;

        len = nopaged_len - bmax;

        if (nopaged_len > BUF_SIZE_8KiB) {

                des2 = dma_map_single(priv->device, skb->data, bmax,
                                      DMA_TO_DEVICE);
                desc->des2 = cpu_to_le32(des2);
                if (dma_mapping_error(priv->device, des2))
                        return -1;

                tx_q->tx_skbuff_dma[entry].buf = des2;
                tx_q->tx_skbuff_dma[entry].len = bmax;
                tx_q->tx_skbuff_dma[entry].is_jumbo = true;

                desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
                stmmac_prepare_tx_desc(priv, desc, 1, bmax, csum,
                                STMMAC_RING_MODE, 0, false, skb->len);
                tx_q->tx_skbuff[entry] = NULL;
                entry = STMMAC_NEXT_ENTRY(entry, priv->dma_conf.dma_tx_size);

                if (priv->extend_desc)
                        desc = (struct dma_desc *)(tx_q->dma_etx + entry);
                else
                        desc = tx_q->dma_tx + entry;

                des2 = dma_map_single(priv->device, skb->data + bmax, len,
                                      DMA_TO_DEVICE);
                desc->des2 = cpu_to_le32(des2);
                if (dma_mapping_error(priv->device, des2))
                        return -1;
                tx_q->tx_skbuff_dma[entry].buf = des2;
                tx_q->tx_skbuff_dma[entry].len = len;
                tx_q->tx_skbuff_dma[entry].is_jumbo = true;

                desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
                stmmac_prepare_tx_desc(priv, desc, 0, len, csum,
                                STMMAC_RING_MODE, 1, !skb_is_nonlinear(skb),
                                skb->len);
        } else {
                des2 = dma_map_single(priv->device, skb->data,
                                      nopaged_len, DMA_TO_DEVICE);
                desc->des2 = cpu_to_le32(des2);
                if (dma_mapping_error(priv->device, des2))
                        return -1;
                tx_q->tx_skbuff_dma[entry].buf = des2;
                tx_q->tx_skbuff_dma[entry].len = nopaged_len;
                tx_q->tx_skbuff_dma[entry].is_jumbo = true;
                desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
                stmmac_prepare_tx_desc(priv, desc, 1, nopaged_len, csum,
                                STMMAC_RING_MODE, 0, !skb_is_nonlinear(skb),
                                skb->len);
        }

        tx_q->cur_tx = entry;

        return entry;
}

static bool is_jumbo_frm(unsigned int len, bool enh_desc)
{
        return len >= BUF_SIZE_4KiB;
}

static void refill_desc3(struct stmmac_rx_queue *rx_q, struct dma_desc *p)
{
        struct stmmac_priv *priv = rx_q->priv_data;

        /* Fill DES3 in case of RING mode */
        if (priv->dma_conf.dma_buf_sz == BUF_SIZE_16KiB)
                p->des3 = cpu_to_le32(le32_to_cpu(p->des2) + BUF_SIZE_8KiB);
}

/* In ring mode we need to fill the desc3 because it is used as buffer */
static void init_desc3(struct dma_desc *p)
{
        p->des3 = cpu_to_le32(le32_to_cpu(p->des2) + BUF_SIZE_8KiB);
}

static void clean_desc3(struct stmmac_tx_queue *tx_q, struct dma_desc *p)
{
        struct stmmac_priv *priv = tx_q->priv_data;
        unsigned int entry = tx_q->dirty_tx;

        /* des3 is only used for jumbo frames tx or time stamping */
        if (unlikely(tx_q->tx_skbuff_dma[entry].is_jumbo ||
                     (tx_q->tx_skbuff_dma[entry].last_segment &&
                      !priv->extend_desc && priv->hwts_tx_en)))
                p->des3 = 0;
}

static int set_16kib_bfsize(int mtu)
{
        int ret = 0;
        if (unlikely(mtu > BUF_SIZE_8KiB))
                ret = BUF_SIZE_16KiB;
        return ret;
}

const struct stmmac_mode_ops ring_mode_ops = {
        .is_jumbo_frm = is_jumbo_frm,
        .jumbo_frm = jumbo_frm,
        .refill_desc3 = refill_desc3,
        .init_desc3 = init_desc3,
        .clean_desc3 = clean_desc3,
        .set_16kib_bfsize = set_16kib_bfsize,
};