// SPDX-License-Identifier: GPL-2.0-only
// Copyright 2025 Cisco Systems, Inc.  All rights reserved.

#include <net/netdev_queues.h>
#include "enic_res.h"
#include "enic.h"
#include "enic_wq.h"

#define ENET_CQ_DESC_COMP_NDX_BITS 14
#define ENET_CQ_DESC_COMP_NDX_MASK GENMASK(ENET_CQ_DESC_COMP_NDX_BITS - 1, 0)

static void enic_wq_cq_desc_dec(const struct cq_desc *desc_arg, bool ext_wq,
                                u8 *type, u8 *color, u16 *q_number,
                                u16 *completed_index)
{
        const struct cq_desc *desc = desc_arg;
        const u8 type_color = desc->type_color;

        *color = (type_color >> CQ_DESC_COLOR_SHIFT) & CQ_DESC_COLOR_MASK;

        /*
         * Make sure color bit is read from desc *before* other fields
         * are read from desc.  Hardware guarantees color bit is last
         * bit (byte) written.  Adding the rmb() prevents the compiler
         * and/or CPU from reordering the reads which would potentially
         * result in reading stale values.
         */
        rmb();

        *type = type_color & CQ_DESC_TYPE_MASK;
        *q_number = le16_to_cpu(desc->q_number) & CQ_DESC_Q_NUM_MASK;

        if (ext_wq)
                *completed_index = le16_to_cpu(desc->completed_index) &
                        ENET_CQ_DESC_COMP_NDX_MASK;
        else
                *completed_index = le16_to_cpu(desc->completed_index) &
                        CQ_DESC_COMP_NDX_MASK;
}

void enic_free_wq_buf(struct vnic_wq *wq, struct vnic_wq_buf *buf)
{
        struct enic *enic = vnic_dev_priv(wq->vdev);

        if (buf->sop)
                dma_unmap_single(&enic->pdev->dev, buf->dma_addr, buf->len,
                                 DMA_TO_DEVICE);
        else
                dma_unmap_page(&enic->pdev->dev, buf->dma_addr, buf->len,
                               DMA_TO_DEVICE);

        if (buf->os_buf)
                dev_kfree_skb_any(buf->os_buf);
}

static void enic_wq_free_buf(struct vnic_wq *wq, struct cq_desc *cq_desc,
                             struct vnic_wq_buf *buf, void *opaque)
{
        struct enic *enic = vnic_dev_priv(wq->vdev);

        enic->wq[wq->index].stats.cq_work++;
        enic->wq[wq->index].stats.cq_bytes += buf->len;
        enic_free_wq_buf(wq, buf);
}

static void enic_wq_service(struct vnic_dev *vdev, struct cq_desc *cq_desc,
                            u8 type, u16 q_number, u16 completed_index)
{
        struct enic *enic = vnic_dev_priv(vdev);

        spin_lock(&enic->wq[q_number].lock);

        vnic_wq_service(&enic->wq[q_number].vwq, cq_desc,
                        completed_index, enic_wq_free_buf, NULL);

        if (netif_tx_queue_stopped(netdev_get_tx_queue(enic->netdev, q_number))
            && vnic_wq_desc_avail(&enic->wq[q_number].vwq) >=
            (MAX_SKB_FRAGS + ENIC_DESC_MAX_SPLITS)) {
                netif_wake_subqueue(enic->netdev, q_number);
                enic->wq[q_number].stats.wake++;
        }

        spin_unlock(&enic->wq[q_number].lock);
}

unsigned int enic_wq_cq_service(struct enic *enic, unsigned int cq_index,
                                unsigned int work_to_do)
{
        struct vnic_cq *cq = &enic->cq[cq_index];
        u16 q_number, completed_index;
        unsigned int work_done = 0;
        struct cq_desc *cq_desc;
        u8 type, color;
        bool ext_wq;

        ext_wq = cq->ring.size > ENIC_MAX_WQ_DESCS_DEFAULT;

        cq_desc = (struct cq_desc *)vnic_cq_to_clean(cq);
        enic_wq_cq_desc_dec(cq_desc, ext_wq, &type, &color,
                            &q_number, &completed_index);

        while (color != cq->last_color) {
                enic_wq_service(cq->vdev, cq_desc, type, q_number,
                                completed_index);

                vnic_cq_inc_to_clean(cq);

                if (++work_done >= work_to_do)
                        break;

                cq_desc = (struct cq_desc *)vnic_cq_to_clean(cq);
                enic_wq_cq_desc_dec(cq_desc, ext_wq, &type, &color,
                                    &q_number, &completed_index);
        }

        return work_done;
}