// SPDX-License-Identifier: GPL-2.0-only
/*
 * Huawei HiNIC PCI Express Linux driver
 * Copyright(c) 2017 Huawei Technologies Co., Ltd
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/pci.h>
#include <linux/device.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/u64_stats_sync.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/skbuff.h>
#include <linux/dma-mapping.h>
#include <linux/prefetch.h>
#include <linux/cpumask.h>
#include <linux/if_vlan.h>
#include <asm/barrier.h>

#include "hinic_common.h"
#include "hinic_hw_if.h"
#include "hinic_hw_wqe.h"
#include "hinic_hw_wq.h"
#include "hinic_hw_qp.h"
#include "hinic_hw_dev.h"
#include "hinic_rx.h"
#include "hinic_dev.h"

#define RX_IRQ_NO_PENDING               0
#define RX_IRQ_NO_COALESC               0
#define RX_IRQ_NO_LLI_TIMER             0
#define RX_IRQ_NO_CREDIT                0
#define RX_IRQ_NO_RESEND_TIMER          0
#define HINIC_RX_BUFFER_WRITE           16

#define HINIC_RX_IPV6_PKT               7
#define LRO_PKT_HDR_LEN_IPV4            66
#define LRO_PKT_HDR_LEN_IPV6            86
#define LRO_REPLENISH_THLD              256

#define LRO_PKT_HDR_LEN(cqe)            \
        (HINIC_GET_RX_PKT_TYPE(be32_to_cpu((cqe)->offload_type)) == \
         HINIC_RX_IPV6_PKT ? LRO_PKT_HDR_LEN_IPV6 : LRO_PKT_HDR_LEN_IPV4)

/**
 * hinic_rxq_clean_stats - Clean the statistics of specific queue
 * @rxq: Logical Rx Queue
 **/
static void hinic_rxq_clean_stats(struct hinic_rxq *rxq)
{
        struct hinic_rxq_stats *rxq_stats = &rxq->rxq_stats;

        u64_stats_update_begin(&rxq_stats->syncp);
        rxq_stats->pkts  = 0;
        rxq_stats->bytes = 0;
        rxq_stats->errors = 0;
        rxq_stats->csum_errors = 0;
        rxq_stats->other_errors = 0;
        u64_stats_update_end(&rxq_stats->syncp);
}

/**
 * hinic_rxq_get_stats - get statistics of Rx Queue
 * @rxq: Logical Rx Queue
 * @stats: return updated stats here
 **/
void hinic_rxq_get_stats(struct hinic_rxq *rxq, struct hinic_rxq_stats *stats)
{
        struct hinic_rxq_stats *rxq_stats = &rxq->rxq_stats;
        unsigned int start;

        do {
                start = u64_stats_fetch_begin(&rxq_stats->syncp);
                stats->pkts = rxq_stats->pkts;
                stats->bytes = rxq_stats->bytes;
                stats->errors = rxq_stats->csum_errors +
                                rxq_stats->other_errors;
                stats->csum_errors = rxq_stats->csum_errors;
                stats->other_errors = rxq_stats->other_errors;
        } while (u64_stats_fetch_retry(&rxq_stats->syncp, start));
}

/**
 * rxq_stats_init - Initialize the statistics of specific queue
 * @rxq: Logical Rx Queue
 **/
static void rxq_stats_init(struct hinic_rxq *rxq)
{
        struct hinic_rxq_stats *rxq_stats = &rxq->rxq_stats;

        u64_stats_init(&rxq_stats->syncp);
        hinic_rxq_clean_stats(rxq);
}

static void rx_csum(struct hinic_rxq *rxq, u32 status,
                    struct sk_buff *skb)
{
        struct net_device *netdev = rxq->netdev;
        u32 csum_err;

        csum_err = HINIC_RQ_CQE_STATUS_GET(status, CSUM_ERR);

        if (!(netdev->features & NETIF_F_RXCSUM))
                return;

        if (!csum_err) {
                skb->ip_summed = CHECKSUM_UNNECESSARY;
        } else {
                if (!(csum_err & (HINIC_RX_CSUM_HW_CHECK_NONE |
                        HINIC_RX_CSUM_IPSU_OTHER_ERR)))
                        rxq->rxq_stats.csum_errors++;
                skb->ip_summed = CHECKSUM_NONE;
        }
}

/**
 * rx_alloc_skb - allocate skb and map it to dma address
 * @rxq: rx queue
 * @dma_addr: returned dma address for the skb
 *
 * Return skb
 **/
static struct sk_buff *rx_alloc_skb(struct hinic_rxq *rxq,
                                    dma_addr_t *dma_addr)
{
        struct hinic_dev *nic_dev = netdev_priv(rxq->netdev);
        struct hinic_hwdev *hwdev = nic_dev->hwdev;
        struct hinic_hwif *hwif = hwdev->hwif;
        struct pci_dev *pdev = hwif->pdev;
        struct sk_buff *skb;
        dma_addr_t addr;
        int err;

        skb = netdev_alloc_skb_ip_align(rxq->netdev, rxq->rq->buf_sz);
        if (!skb)
                return NULL;

        addr = dma_map_single(&pdev->dev, skb->data, rxq->rq->buf_sz,
                              DMA_FROM_DEVICE);
        err = dma_mapping_error(&pdev->dev, addr);
        if (err) {
                dev_err(&pdev->dev, "Failed to map Rx DMA, err = %d\n", err);
                goto err_rx_map;
        }

        *dma_addr = addr;
        return skb;

err_rx_map:
        dev_kfree_skb_any(skb);
        return NULL;
}

/**
 * rx_unmap_skb - unmap the dma address of the skb
 * @rxq: rx queue
 * @dma_addr: dma address of the skb
 **/
static void rx_unmap_skb(struct hinic_rxq *rxq, dma_addr_t dma_addr)
{
        struct hinic_dev *nic_dev = netdev_priv(rxq->netdev);
        struct hinic_hwdev *hwdev = nic_dev->hwdev;
        struct hinic_hwif *hwif = hwdev->hwif;
        struct pci_dev *pdev = hwif->pdev;

        dma_unmap_single(&pdev->dev, dma_addr, rxq->rq->buf_sz,
                         DMA_FROM_DEVICE);
}

/**
 * rx_free_skb - unmap and free skb
 * @rxq: rx queue
 * @skb: skb to free
 * @dma_addr: dma address of the skb
 **/
static void rx_free_skb(struct hinic_rxq *rxq, struct sk_buff *skb,
                        dma_addr_t dma_addr)
{
        rx_unmap_skb(rxq, dma_addr);
        dev_kfree_skb_any(skb);
}

/**
 * rx_alloc_pkts - allocate pkts in rx queue
 * @rxq: rx queue
 *
 * Return number of skbs allocated
 **/
static int rx_alloc_pkts(struct hinic_rxq *rxq)
{
        struct hinic_dev *nic_dev = netdev_priv(rxq->netdev);
        struct hinic_rq_wqe *rq_wqe;
        unsigned int free_wqebbs;
        struct hinic_sge sge;
        dma_addr_t dma_addr;
        struct sk_buff *skb;
        u16 prod_idx;
        int i;

        free_wqebbs = hinic_get_rq_free_wqebbs(rxq->rq);

        /* Limit the allocation chunks */
        if (free_wqebbs > nic_dev->rx_weight)
                free_wqebbs = nic_dev->rx_weight;

        for (i = 0; i < free_wqebbs; i++) {
                skb = rx_alloc_skb(rxq, &dma_addr);
                if (!skb)
                        goto skb_out;

                hinic_set_sge(&sge, dma_addr, skb->len);

                rq_wqe = hinic_rq_get_wqe(rxq->rq, HINIC_RQ_WQE_SIZE,
                                          &prod_idx);
                if (!rq_wqe) {
                        rx_free_skb(rxq, skb, dma_addr);
                        goto skb_out;
                }

                hinic_rq_prepare_wqe(rxq->rq, prod_idx, rq_wqe, &sge);

                hinic_rq_write_wqe(rxq->rq, prod_idx, rq_wqe, skb);
        }

skb_out:
        if (i) {
                wmb();  /* write all the wqes before update PI */

                hinic_rq_update(rxq->rq, prod_idx);
        }

        return i;
}

/**
 * free_all_rx_skbs - free all skbs in rx queue
 * @rxq: rx queue
 **/
static void free_all_rx_skbs(struct hinic_rxq *rxq)
{
        struct hinic_rq *rq = rxq->rq;
        struct hinic_hw_wqe *hw_wqe;
        struct hinic_sge sge;
        u16 ci;

        while ((hw_wqe = hinic_read_wqe(rq->wq, HINIC_RQ_WQE_SIZE, &ci))) {
                if (IS_ERR(hw_wqe))
                        break;

                hinic_rq_get_sge(rq, &hw_wqe->rq_wqe, ci, &sge);

                hinic_put_wqe(rq->wq, HINIC_RQ_WQE_SIZE);

                rx_free_skb(rxq, rq->saved_skb[ci], hinic_sge_to_dma(&sge));
        }
}

/**
 * rx_recv_jumbo_pkt - Rx handler for jumbo pkt
 * @rxq: rx queue
 * @head_skb: the first skb in the list
 * @left_pkt_len: left size of the pkt exclude head skb
 * @ci: consumer index
 *
 * Return number of wqes that used for the left of the pkt
 **/
static int rx_recv_jumbo_pkt(struct hinic_rxq *rxq, struct sk_buff *head_skb,
                             unsigned int left_pkt_len, u16 ci)
{
        struct sk_buff *skb, *curr_skb = head_skb;
        struct hinic_rq_wqe *rq_wqe;
        unsigned int curr_len;
        struct hinic_sge sge;
        int num_wqes = 0;

        while (left_pkt_len > 0) {
                rq_wqe = hinic_rq_read_next_wqe(rxq->rq, HINIC_RQ_WQE_SIZE,
                                                &skb, &ci);

                num_wqes++;

                hinic_rq_get_sge(rxq->rq, rq_wqe, ci, &sge);

                rx_unmap_skb(rxq, hinic_sge_to_dma(&sge));

                prefetch(skb->data);

                curr_len = (left_pkt_len > HINIC_RX_BUF_SZ) ? HINIC_RX_BUF_SZ :
                            left_pkt_len;

                left_pkt_len -= curr_len;

                __skb_put(skb, curr_len);

                if (curr_skb == head_skb)
                        skb_shinfo(head_skb)->frag_list = skb;
                else
                        curr_skb->next = skb;

                head_skb->len += skb->len;
                head_skb->data_len += skb->len;
                head_skb->truesize += skb->truesize;

                curr_skb = skb;
        }

        return num_wqes;
}

static void hinic_copy_lp_data(struct hinic_dev *nic_dev,
                               struct sk_buff *skb)
{
        struct net_device *netdev = nic_dev->netdev;
        u8 *lb_buf = nic_dev->lb_test_rx_buf;
        int lb_len = nic_dev->lb_pkt_len;
        int pkt_offset, frag_len, i;
        void *frag_data = NULL;

        if (nic_dev->lb_test_rx_idx == LP_PKT_CNT) {
                nic_dev->lb_test_rx_idx = 0;
                netif_warn(nic_dev, drv, netdev, "Loopback test warning, receive too more test pkts\n");
        }

        if (skb->len != nic_dev->lb_pkt_len) {
                netif_warn(nic_dev, drv, netdev, "Wrong packet length\n");
                nic_dev->lb_test_rx_idx++;
                return;
        }

        pkt_offset = nic_dev->lb_test_rx_idx * lb_len;
        frag_len = (int)skb_headlen(skb);
        memcpy(lb_buf + pkt_offset, skb->data, frag_len);
        pkt_offset += frag_len;
        for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
                frag_data = skb_frag_address(&skb_shinfo(skb)->frags[i]);
                frag_len = (int)skb_frag_size(&skb_shinfo(skb)->frags[i]);
                memcpy((lb_buf + pkt_offset), frag_data, frag_len);
                pkt_offset += frag_len;
        }
        nic_dev->lb_test_rx_idx++;
}

/**
 * rxq_recv - Rx handler
 * @rxq: rx queue
 * @budget: maximum pkts to process
 *
 * Return number of pkts received
 **/
static int rxq_recv(struct hinic_rxq *rxq, int budget)
{
        struct hinic_qp *qp = container_of(rxq->rq, struct hinic_qp, rq);
        struct net_device *netdev = rxq->netdev;
        u64 pkt_len = 0, rx_bytes = 0;
        struct hinic_rq *rq = rxq->rq;
        struct hinic_rq_wqe *rq_wqe;
        struct hinic_dev *nic_dev;
        unsigned int free_wqebbs;
        struct hinic_rq_cqe *cqe;
        int num_wqes, pkts = 0;
        struct hinic_sge sge;
        unsigned int status;
        struct sk_buff *skb;
        u32 offload_type;
        u16 ci, num_lro;
        u16 num_wqe = 0;
        u32 vlan_len;
        u16 vid;

        nic_dev = netdev_priv(netdev);

        while (pkts < budget) {
                num_wqes = 0;

                rq_wqe = hinic_rq_read_wqe(rxq->rq, HINIC_RQ_WQE_SIZE, &skb,
                                           &ci);
                if (!rq_wqe)
                        break;

                /* make sure we read rx_done before packet length */
                dma_rmb();

                cqe = rq->cqe[ci];
                status =  be32_to_cpu(cqe->status);
                hinic_rq_get_sge(rxq->rq, rq_wqe, ci, &sge);

                rx_unmap_skb(rxq, hinic_sge_to_dma(&sge));

                rx_csum(rxq, status, skb);

                prefetch(skb->data);

                pkt_len = sge.len;

                if (pkt_len <= HINIC_RX_BUF_SZ) {
                        __skb_put(skb, pkt_len);
                } else {
                        __skb_put(skb, HINIC_RX_BUF_SZ);
                        num_wqes = rx_recv_jumbo_pkt(rxq, skb, pkt_len -
                                                     HINIC_RX_BUF_SZ, ci);
                }

                hinic_rq_put_wqe(rq, ci,
                                 (num_wqes + 1) * HINIC_RQ_WQE_SIZE);

                offload_type = be32_to_cpu(cqe->offload_type);
                vlan_len = be32_to_cpu(cqe->len);
                if ((netdev->features & NETIF_F_HW_VLAN_CTAG_RX) &&
                    HINIC_GET_RX_VLAN_OFFLOAD_EN(offload_type)) {
                        vid = HINIC_GET_RX_VLAN_TAG(vlan_len);
                        __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), vid);
                }

                if (unlikely(nic_dev->flags & HINIC_LP_TEST))
                        hinic_copy_lp_data(nic_dev, skb);

                skb_record_rx_queue(skb, qp->q_id);
                skb->protocol = eth_type_trans(skb, rxq->netdev);

                napi_gro_receive(&rxq->napi, skb);

                pkts++;
                rx_bytes += pkt_len;

                num_lro = HINIC_GET_RX_NUM_LRO(status);
                if (num_lro) {
                        rx_bytes += ((num_lro - 1) *
                                     LRO_PKT_HDR_LEN(cqe));

                        num_wqe +=
                        (u16)(pkt_len >> rxq->rx_buff_shift) +
                        ((pkt_len & (rxq->buf_len - 1)) ? 1 : 0);
                }

                cqe->status = 0;

                if (num_wqe >= LRO_REPLENISH_THLD)
                        break;
        }

        free_wqebbs = hinic_get_rq_free_wqebbs(rxq->rq);
        if (free_wqebbs > HINIC_RX_BUFFER_WRITE)
                rx_alloc_pkts(rxq);

        u64_stats_update_begin(&rxq->rxq_stats.syncp);
        rxq->rxq_stats.pkts += pkts;
        rxq->rxq_stats.bytes += rx_bytes;
        u64_stats_update_end(&rxq->rxq_stats.syncp);

        return pkts;
}

static int rx_poll(struct napi_struct *napi, int budget)
{
        struct hinic_rxq *rxq = container_of(napi, struct hinic_rxq, napi);
        struct hinic_dev *nic_dev = netdev_priv(rxq->netdev);
        struct hinic_rq *rq = rxq->rq;
        int pkts;

        pkts = rxq_recv(rxq, budget);
        if (pkts >= budget)
                return budget;

        napi_complete(napi);

        if (!HINIC_IS_VF(nic_dev->hwdev->hwif))
                hinic_hwdev_set_msix_state(nic_dev->hwdev,
                                           rq->msix_entry,
                                           HINIC_MSIX_ENABLE);

        return pkts;
}

static void rx_add_napi(struct hinic_rxq *rxq)
{
        struct hinic_dev *nic_dev = netdev_priv(rxq->netdev);

        netif_napi_add_weight(rxq->netdev, &rxq->napi, rx_poll,
                              nic_dev->rx_weight);
        napi_enable(&rxq->napi);
}

static void rx_del_napi(struct hinic_rxq *rxq)
{
        napi_disable(&rxq->napi);
        netif_napi_del(&rxq->napi);
}

static irqreturn_t rx_irq(int irq, void *data)
{
        struct hinic_rxq *rxq = (struct hinic_rxq *)data;
        struct hinic_rq *rq = rxq->rq;
        struct hinic_dev *nic_dev;

        /* Disable the interrupt until napi will be completed */
        nic_dev = netdev_priv(rxq->netdev);
        if (!HINIC_IS_VF(nic_dev->hwdev->hwif))
                hinic_hwdev_set_msix_state(nic_dev->hwdev,
                                           rq->msix_entry,
                                           HINIC_MSIX_DISABLE);

        nic_dev = netdev_priv(rxq->netdev);
        hinic_hwdev_msix_cnt_set(nic_dev->hwdev, rq->msix_entry);

        napi_schedule(&rxq->napi);
        return IRQ_HANDLED;
}

static int rx_request_irq(struct hinic_rxq *rxq)
{
        struct hinic_dev *nic_dev = netdev_priv(rxq->netdev);
        struct hinic_msix_config interrupt_info = {0};
        struct hinic_intr_coal_info *intr_coal = NULL;
        struct hinic_hwdev *hwdev = nic_dev->hwdev;
        struct hinic_rq *rq = rxq->rq;
        struct hinic_qp *qp;
        int err;

        qp = container_of(rq, struct hinic_qp, rq);

        rx_add_napi(rxq);

        hinic_hwdev_msix_set(hwdev, rq->msix_entry,
                             RX_IRQ_NO_PENDING, RX_IRQ_NO_COALESC,
                             RX_IRQ_NO_LLI_TIMER, RX_IRQ_NO_CREDIT,
                             RX_IRQ_NO_RESEND_TIMER);

        intr_coal = &nic_dev->rx_intr_coalesce[qp->q_id];
        interrupt_info.msix_index = rq->msix_entry;
        interrupt_info.coalesce_timer_cnt = intr_coal->coalesce_timer_cfg;
        interrupt_info.pending_cnt = intr_coal->pending_limt;
        interrupt_info.resend_timer_cnt = intr_coal->resend_timer_cfg;

        err = hinic_set_interrupt_cfg(hwdev, &interrupt_info);
        if (err) {
                netif_err(nic_dev, drv, rxq->netdev,
                          "Failed to set RX interrupt coalescing attribute\n");
                goto err_req_irq;
        }

        err = request_irq(rq->irq, rx_irq, 0, rxq->irq_name, rxq);
        if (err)
                goto err_req_irq;

        cpumask_set_cpu(qp->q_id % num_online_cpus(), &rq->affinity_mask);
        err = irq_set_affinity_and_hint(rq->irq, &rq->affinity_mask);
        if (err)
                goto err_irq_affinity;

        return 0;

err_irq_affinity:
        free_irq(rq->irq, rxq);
err_req_irq:
        rx_del_napi(rxq);
        return err;
}

static void rx_free_irq(struct hinic_rxq *rxq)
{
        struct hinic_rq *rq = rxq->rq;

        irq_update_affinity_hint(rq->irq, NULL);
        free_irq(rq->irq, rxq);
        rx_del_napi(rxq);
}

/**
 * hinic_init_rxq - Initialize the Rx Queue
 * @rxq: Logical Rx Queue
 * @rq: Hardware Rx Queue to connect the Logical queue with
 * @netdev: network device to connect the Logical queue with
 *
 * Return 0 - Success, negative - Failure
 **/
int hinic_init_rxq(struct hinic_rxq *rxq, struct hinic_rq *rq,
                   struct net_device *netdev)
{
        struct hinic_qp *qp = container_of(rq, struct hinic_qp, rq);
        int err, pkts;

        rxq->netdev = netdev;
        rxq->rq = rq;
        rxq->buf_len = HINIC_RX_BUF_SZ;
        rxq->rx_buff_shift = ilog2(HINIC_RX_BUF_SZ);

        rxq_stats_init(rxq);

        rxq->irq_name = devm_kasprintf(&netdev->dev, GFP_KERNEL,
                                       "%s_rxq%d", netdev->name, qp->q_id);
        if (!rxq->irq_name)
                return -ENOMEM;

        pkts = rx_alloc_pkts(rxq);
        if (!pkts) {
                err = -ENOMEM;
                goto err_rx_pkts;
        }

        err = rx_request_irq(rxq);
        if (err) {
                netdev_err(netdev, "Failed to request Rx irq\n");
                goto err_req_rx_irq;
        }

        return 0;

err_req_rx_irq:
err_rx_pkts:
        free_all_rx_skbs(rxq);
        devm_kfree(&netdev->dev, rxq->irq_name);
        return err;
}

/**
 * hinic_clean_rxq - Clean the Rx Queue
 * @rxq: Logical Rx Queue
 **/
void hinic_clean_rxq(struct hinic_rxq *rxq)
{
        struct net_device *netdev = rxq->netdev;

        rx_free_irq(rxq);

        free_all_rx_skbs(rxq);
        devm_kfree(&netdev->dev, rxq->irq_name);
}