// SPDX-License-Identifier: GPL-2.0+
/* Microchip lan969x Switch driver
 *
 * Copyright (c) 2025 Microchip Technology Inc. and its subsidiaries.
 */
#include <net/page_pool/helpers.h>

#include "../sparx5_main.h"
#include "../sparx5_main_regs.h"
#include "../sparx5_port.h"

#include "fdma_api.h"
#include "lan969x.h"

#define FDMA_PRIV(fdma) ((struct sparx5 *)((fdma)->priv))

static int lan969x_fdma_tx_dataptr_cb(struct fdma *fdma, int dcb, int db,
                                      u64 *dataptr)
{
        *dataptr = FDMA_PRIV(fdma)->tx.dbs[dcb].dma_addr;

        return 0;
}

static int lan969x_fdma_rx_dataptr_cb(struct fdma *fdma, int dcb, int db,
                                      u64 *dataptr)
{
        struct sparx5_rx *rx = &FDMA_PRIV(fdma)->rx;
        struct page *page;

        page = page_pool_dev_alloc_pages(rx->page_pool);
        if (unlikely(!page))
                return -ENOMEM;

        rx->page[dcb][db] = page;

        *dataptr = page_pool_get_dma_addr(page);

        return 0;
}

static int lan969x_fdma_get_next_dcb(struct sparx5_tx *tx)
{
        struct fdma *fdma = &tx->fdma;

        for (int i = 0; i < fdma->n_dcbs; ++i)
                if (!tx->dbs[i].used && !fdma_is_last(fdma, &fdma->dcbs[i]))
                        return i;

        return -ENOSPC;
}

static void lan969x_fdma_tx_clear_buf(struct sparx5 *sparx5, int weight)
{
        struct fdma *fdma = &sparx5->tx.fdma;
        struct sparx5_tx_buf *db;
        unsigned long flags;
        int i;

        spin_lock_irqsave(&sparx5->tx_lock, flags);

        for (i = 0; i < fdma->n_dcbs; ++i) {
                db = &sparx5->tx.dbs[i];

                if (!db->used)
                        continue;

                if (!fdma_db_is_done(fdma_db_get(fdma, i, 0)))
                        continue;

                db->dev->stats.tx_bytes += db->skb->len;
                db->dev->stats.tx_packets++;
                sparx5->tx.packets++;

                dma_unmap_single(sparx5->dev,
                                 db->dma_addr,
                                 db->skb->len,
                                 DMA_TO_DEVICE);

                if (!db->ptp)
                        napi_consume_skb(db->skb, weight);

                db->used = false;
        }

        spin_unlock_irqrestore(&sparx5->tx_lock, flags);
}

static void lan969x_fdma_free_pages(struct sparx5_rx *rx)
{
        struct fdma *fdma = &rx->fdma;

        for (int i = 0; i < fdma->n_dcbs; ++i) {
                for (int j = 0; j < fdma->n_dbs; ++j)
                        page_pool_put_full_page(rx->page_pool,
                                                rx->page[i][j], false);
        }
}

static struct sk_buff *lan969x_fdma_rx_get_frame(struct sparx5 *sparx5,
                                                 struct sparx5_rx *rx)
{
        const struct sparx5_consts *consts = sparx5->data->consts;
        struct fdma *fdma = &rx->fdma;
        struct sparx5_port *port;
        struct frame_info fi;
        struct sk_buff *skb;
        struct fdma_db *db;
        struct page *page;

        db = &fdma->dcbs[fdma->dcb_index].db[fdma->db_index];
        page = rx->page[fdma->dcb_index][fdma->db_index];

        sparx5_ifh_parse(sparx5, page_address(page), &fi);
        port = fi.src_port < consts->n_ports ? sparx5->ports[fi.src_port] :
                                               NULL;
        if (WARN_ON(!port))
                goto free_page;

        skb = build_skb(page_address(page), fdma->db_size);
        if (unlikely(!skb))
                goto free_page;

        skb_mark_for_recycle(skb);
        skb_put(skb, fdma_db_len_get(db));
        skb_pull(skb, IFH_LEN * sizeof(u32));

        skb->dev = port->ndev;

        if (likely(!(skb->dev->features & NETIF_F_RXFCS)))
                skb_trim(skb, skb->len - ETH_FCS_LEN);

        sparx5_ptp_rxtstamp(sparx5, skb, fi.timestamp);
        skb->protocol = eth_type_trans(skb, skb->dev);

        if (test_bit(port->portno, sparx5->bridge_mask))
                skb->offload_fwd_mark = 1;

        skb->dev->stats.rx_bytes += skb->len;
        skb->dev->stats.rx_packets++;

        return skb;

free_page:
        page_pool_recycle_direct(rx->page_pool, page);

        return NULL;
}

static int lan969x_fdma_rx_alloc(struct sparx5 *sparx5)
{
        struct sparx5_rx *rx = &sparx5->rx;
        struct fdma *fdma = &rx->fdma;
        int err;

        struct page_pool_params pp_params = {
                .order = 0,
                .flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV,
                .pool_size = fdma->n_dcbs * fdma->n_dbs,
                .nid = NUMA_NO_NODE,
                .dev = sparx5->dev,
                .dma_dir = DMA_FROM_DEVICE,
                .offset = 0,
                .max_len = fdma->db_size -
                           SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
        };

        rx->page_pool = page_pool_create(&pp_params);
        if (IS_ERR(rx->page_pool))
                return PTR_ERR(rx->page_pool);

        err = fdma_alloc_coherent(sparx5->dev, fdma);
        if (err)
                return err;

        fdma_dcbs_init(fdma,
                       FDMA_DCB_INFO_DATAL(fdma->db_size),
                       FDMA_DCB_STATUS_INTR);

        return 0;
}

static int lan969x_fdma_tx_alloc(struct sparx5 *sparx5)
{
        struct sparx5_tx *tx = &sparx5->tx;
        struct fdma *fdma = &tx->fdma;
        int err;

        tx->dbs = kzalloc_objs(struct sparx5_tx_buf, fdma->n_dcbs);
        if (!tx->dbs)
                return -ENOMEM;

        err = fdma_alloc_coherent(sparx5->dev, fdma);
        if (err) {
                kfree(tx->dbs);
                return err;
        }

        fdma_dcbs_init(fdma,
                       FDMA_DCB_INFO_DATAL(fdma->db_size),
                       FDMA_DCB_STATUS_DONE);

        return 0;
}

static void lan969x_fdma_rx_init(struct sparx5 *sparx5)
{
        struct fdma *fdma = &sparx5->rx.fdma;

        fdma->channel_id = FDMA_XTR_CHANNEL;
        fdma->n_dcbs = FDMA_DCB_MAX;
        fdma->n_dbs = 1;
        fdma->priv = sparx5;
        fdma->size = fdma_get_size(fdma);
        fdma->db_size = PAGE_SIZE;
        fdma->ops.dataptr_cb = &lan969x_fdma_rx_dataptr_cb;
        fdma->ops.nextptr_cb = &fdma_nextptr_cb;

        /* Fetch a netdev for SKB and NAPI use, any will do */
        for (int idx = 0; idx < sparx5->data->consts->n_ports; ++idx) {
                struct sparx5_port *port = sparx5->ports[idx];

                if (port && port->ndev) {
                        sparx5->rx.ndev = port->ndev;
                        break;
                }
        }
}

static void lan969x_fdma_tx_init(struct sparx5 *sparx5)
{
        struct fdma *fdma = &sparx5->tx.fdma;

        fdma->channel_id = FDMA_INJ_CHANNEL;
        fdma->n_dcbs = FDMA_DCB_MAX;
        fdma->n_dbs = 1;
        fdma->priv = sparx5;
        fdma->size = fdma_get_size(fdma);
        fdma->db_size = PAGE_SIZE;
        fdma->ops.dataptr_cb = &lan969x_fdma_tx_dataptr_cb;
        fdma->ops.nextptr_cb = &fdma_nextptr_cb;
}

int lan969x_fdma_napi_poll(struct napi_struct *napi, int weight)
{
        struct sparx5_rx *rx = container_of(napi, struct sparx5_rx, napi);
        struct sparx5 *sparx5 = container_of(rx, struct sparx5, rx);
        int old_dcb, dcb_reload, counter = 0;
        struct fdma *fdma = &rx->fdma;
        struct sk_buff *skb;

        dcb_reload = fdma->dcb_index;

        lan969x_fdma_tx_clear_buf(sparx5, weight);

        /* Process RX data */
        while (counter < weight) {
                if (!fdma_has_frames(fdma))
                        break;

                skb = lan969x_fdma_rx_get_frame(sparx5, rx);
                if (!skb)
                        break;

                napi_gro_receive(&rx->napi, skb);

                fdma_db_advance(fdma);
                counter++;
                /* Check if the DCB can be reused */
                if (fdma_dcb_is_reusable(fdma))
                        continue;

                fdma_db_reset(fdma);
                fdma_dcb_advance(fdma);
        }

        /* Allocate new pages and map them */
        while (dcb_reload != fdma->dcb_index) {
                old_dcb = dcb_reload;
                dcb_reload++;
                 /* n_dcbs must be a power of 2 */
                dcb_reload &= fdma->n_dcbs - 1;

                fdma_dcb_add(fdma,
                             old_dcb,
                             FDMA_DCB_INFO_DATAL(fdma->db_size),
                             FDMA_DCB_STATUS_INTR);

                sparx5_fdma_reload(sparx5, fdma);
        }

        if (counter < weight && napi_complete_done(napi, counter))
                spx5_wr(0xff, sparx5, FDMA_INTR_DB_ENA);

        return counter;
}

int lan969x_fdma_xmit(struct sparx5 *sparx5, u32 *ifh, struct sk_buff *skb,
                      struct net_device *dev)
{
        int next_dcb, needed_headroom, needed_tailroom, err;
        struct sparx5_tx *tx = &sparx5->tx;
        struct fdma *fdma = &tx->fdma;
        struct sparx5_tx_buf *db_buf;
        u64 status;

        next_dcb = lan969x_fdma_get_next_dcb(tx);
        if (next_dcb < 0)
                return -EBUSY;

        needed_headroom = max_t(int, IFH_LEN * 4 - skb_headroom(skb), 0);
        needed_tailroom = max_t(int, ETH_FCS_LEN - skb_tailroom(skb), 0);
        if (needed_headroom || needed_tailroom || skb_header_cloned(skb)) {
                err = pskb_expand_head(skb, needed_headroom, needed_tailroom,
                                       GFP_ATOMIC);
                if (unlikely(err))
                        return err;
        }

        skb_push(skb, IFH_LEN * 4);
        memcpy(skb->data, ifh, IFH_LEN * 4);
        skb_put(skb, ETH_FCS_LEN);

        db_buf = &tx->dbs[next_dcb];
        db_buf->dma_addr = dma_map_single(sparx5->dev,
                                          skb->data,
                                          skb->len,
                                          DMA_TO_DEVICE);
        if (dma_mapping_error(sparx5->dev, db_buf->dma_addr))
                return -ENOMEM;

        db_buf->dev = dev;
        db_buf->skb = skb;
        db_buf->ptp = false;
        db_buf->used = true;

        if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP &&
            SPARX5_SKB_CB(skb)->rew_op == IFH_REW_OP_TWO_STEP_PTP)
                db_buf->ptp = true;

        status = FDMA_DCB_STATUS_SOF |
                 FDMA_DCB_STATUS_EOF |
                 FDMA_DCB_STATUS_BLOCKO(0) |
                 FDMA_DCB_STATUS_BLOCKL(skb->len) |
                 FDMA_DCB_STATUS_INTR;

        fdma_dcb_advance(fdma);
        fdma_dcb_add(fdma, next_dcb, 0, status);

        sparx5_fdma_reload(sparx5, fdma);

        return NETDEV_TX_OK;
}

int lan969x_fdma_init(struct sparx5 *sparx5)
{
        struct sparx5_rx *rx = &sparx5->rx;
        int err;

        lan969x_fdma_rx_init(sparx5);
        lan969x_fdma_tx_init(sparx5);
        sparx5_fdma_injection_mode(sparx5);

        err = dma_set_mask_and_coherent(sparx5->dev, DMA_BIT_MASK(64));
        if (err) {
                dev_err(sparx5->dev, "Failed to set 64-bit FDMA mask");
                return err;
        }

        err = lan969x_fdma_rx_alloc(sparx5);
        if (err) {
                dev_err(sparx5->dev, "Failed to allocate RX buffers: %d\n",
                        err);
                return err;
        }

        err = lan969x_fdma_tx_alloc(sparx5);
        if (err) {
                fdma_free_coherent(sparx5->dev, &rx->fdma);
                dev_err(sparx5->dev, "Failed to allocate TX buffers: %d\n",
                        err);
                return err;
        }

        /* Reset FDMA state */
        spx5_wr(FDMA_CTRL_NRESET_SET(0), sparx5, FDMA_CTRL);
        spx5_wr(FDMA_CTRL_NRESET_SET(1), sparx5, FDMA_CTRL);

        return err;
}

int lan969x_fdma_deinit(struct sparx5 *sparx5)
{
        struct sparx5_rx *rx = &sparx5->rx;
        struct sparx5_tx *tx = &sparx5->tx;

        sparx5_fdma_stop(sparx5);
        fdma_free_coherent(sparx5->dev, &tx->fdma);
        fdma_free_coherent(sparx5->dev, &rx->fdma);
        lan969x_fdma_free_pages(rx);
        page_pool_destroy(rx->page_pool);

        return 0;
}