// SPDX-License-Identifier: GPL-2.0-only
/*******************************************************************************
  Specialised functions for managing Chained 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, des2;
        unsigned int i = 1, len;
        struct dma_desc *desc;

        desc = tx_q->dma_tx + entry;

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

        len = nopaged_len - bmax;

        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;
        /* do not close the descriptor and do not set own bit */
        stmmac_prepare_tx_desc(priv, desc, 1, bmax, csum, STMMAC_CHAIN_MODE,
                        0, false, skb->len);

        while (len != 0) {
                tx_q->tx_skbuff[entry] = NULL;
                entry = STMMAC_GET_ENTRY(entry, priv->dma_conf.dma_tx_size);
                desc = tx_q->dma_tx + entry;

                if (len > bmax) {
                        des2 = dma_map_single(priv->device,
                                              (skb->data + bmax * i),
                                              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;
                        stmmac_prepare_tx_desc(priv, desc, 0, bmax, csum,
                                        STMMAC_CHAIN_MODE, 1, false, skb->len);
                        len -= bmax;
                        i++;
                } else {
                        des2 = dma_map_single(priv->device,
                                              (skb->data + bmax * i), 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;
                        /* last descriptor can be set now */
                        stmmac_prepare_tx_desc(priv, desc, 0, len, csum,
                                        STMMAC_CHAIN_MODE, 1, true, skb->len);
                        len = 0;
                }
        }

        tx_q->cur_tx = entry;

        return entry;
}

static bool is_jumbo_frm(unsigned int len, bool enh_desc)
{
        bool ret = false;

        if ((enh_desc && (len > BUF_SIZE_8KiB)) ||
            (!enh_desc && (len > BUF_SIZE_2KiB)))
                ret = true;

        return ret;
}

static void init_dma_chain(void *des, dma_addr_t phy_addr,
                                  unsigned int size, unsigned int extend_desc)
{
        /*
         * In chained mode the des3 points to the next element in the ring.
         * The latest element has to point to the head.
         */
        int i;
        dma_addr_t dma_phy = phy_addr;

        if (extend_desc) {
                struct dma_extended_desc *p = (struct dma_extended_desc *)des;
                for (i = 0; i < (size - 1); i++) {
                        dma_phy += sizeof(struct dma_extended_desc);
                        p->basic.des3 = cpu_to_le32((unsigned int)dma_phy);
                        p++;
                }
                p->basic.des3 = cpu_to_le32((unsigned int)phy_addr);

        } else {
                struct dma_desc *p = (struct dma_desc *)des;
                for (i = 0; i < (size - 1); i++) {
                        dma_phy += sizeof(struct dma_desc);
                        p->des3 = cpu_to_le32((unsigned int)dma_phy);
                        p++;
                }
                p->des3 = cpu_to_le32((unsigned int)phy_addr);
        }
}

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

        if (priv->hwts_rx_en && !priv->extend_desc)
                /* NOTE: Device will overwrite des3 with timestamp value if
                 * 1588-2002 time stamping is enabled, hence reinitialize it
                 * to keep explicit chaining in the descriptor.
                 */
                p->des3 = cpu_to_le32((unsigned int)(rx_q->dma_rx_phy +
                                      (((rx_q->dirty_rx) + 1) %
                                       priv->dma_conf.dma_rx_size) *
                                      sizeof(struct dma_desc)));
}

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;

        if (tx_q->tx_skbuff_dma[entry].last_segment && !priv->extend_desc &&
            priv->hwts_tx_en)
                /* NOTE: Device will overwrite des3 with timestamp value if
                 * 1588-2002 time stamping is enabled, hence reinitialize it
                 * to keep explicit chaining in the descriptor.
                 */
                p->des3 = cpu_to_le32((unsigned int)((tx_q->dma_tx_phy +
                                      ((tx_q->dirty_tx + 1) %
                                       priv->dma_conf.dma_tx_size))
                                      * sizeof(struct dma_desc)));
}

const struct stmmac_mode_ops chain_mode_ops = {
        .init = init_dma_chain,
        .is_jumbo_frm = is_jumbo_frm,
        .jumbo_frm = jumbo_frm,
        .refill_desc3 = refill_desc3,
        .clean_desc3 = clean_desc3,
};