// SPDX-License-Identifier: GPL-2.0-only
/* Atlantic Network Driver
 *
 * Copyright (C) 2014-2019 aQuantia Corporation
 * Copyright (C) 2019-2020 Marvell International Ltd.
 */

/* File aq_ring.c: Definition of functions for Rx/Tx rings. */

#include "aq_ring.h"
#include "aq_nic.h"
#include "aq_hw.h"
#include "aq_hw_utils.h"
#include "aq_ptp.h"

#include <linux/netdevice.h>
#include <linux/etherdevice.h>

static inline void aq_free_rxpage(struct aq_rxpage *rxpage, struct device *dev)
{
        unsigned int len = PAGE_SIZE << rxpage->order;

        dma_unmap_page(dev, rxpage->daddr, len, DMA_FROM_DEVICE);

        /* Drop the ref for being in the ring. */
        __free_pages(rxpage->page, rxpage->order);
        rxpage->page = NULL;
}

static int aq_get_rxpage(struct aq_rxpage *rxpage, unsigned int order,
                         struct device *dev)
{
        struct page *page;
        int ret = -ENOMEM;
        dma_addr_t daddr;

        page = dev_alloc_pages(order);
        if (unlikely(!page))
                goto err_exit;

        daddr = dma_map_page(dev, page, 0, PAGE_SIZE << order,
                             DMA_FROM_DEVICE);

        if (unlikely(dma_mapping_error(dev, daddr)))
                goto free_page;

        rxpage->page = page;
        rxpage->daddr = daddr;
        rxpage->order = order;
        rxpage->pg_off = 0;

        return 0;

free_page:
        __free_pages(page, order);

err_exit:
        return ret;
}

static int aq_get_rxpages(struct aq_ring_s *self, struct aq_ring_buff_s *rxbuf,
                          int order)
{
        int ret;

        if (rxbuf->rxdata.page) {
                /* One means ring is the only user and can reuse */
                if (page_ref_count(rxbuf->rxdata.page) > 1) {
                        /* Try reuse buffer */
                        rxbuf->rxdata.pg_off += AQ_CFG_RX_FRAME_MAX;
                        if (rxbuf->rxdata.pg_off + AQ_CFG_RX_FRAME_MAX <=
                                (PAGE_SIZE << order)) {
                                u64_stats_update_begin(&self->stats.rx.syncp);
                                self->stats.rx.pg_flips++;
                                u64_stats_update_end(&self->stats.rx.syncp);
                        } else {
                                /* Buffer exhausted. We have other users and
                                 * should release this page and realloc
                                 */
                                aq_free_rxpage(&rxbuf->rxdata,
                                               aq_nic_get_dev(self->aq_nic));
                                u64_stats_update_begin(&self->stats.rx.syncp);
                                self->stats.rx.pg_losts++;
                                u64_stats_update_end(&self->stats.rx.syncp);
                        }
                } else {
                        rxbuf->rxdata.pg_off = 0;
                        u64_stats_update_begin(&self->stats.rx.syncp);
                        self->stats.rx.pg_reuses++;
                        u64_stats_update_end(&self->stats.rx.syncp);
                }
        }

        if (!rxbuf->rxdata.page) {
                ret = aq_get_rxpage(&rxbuf->rxdata, order,
                                    aq_nic_get_dev(self->aq_nic));
                if (ret) {
                        u64_stats_update_begin(&self->stats.rx.syncp);
                        self->stats.rx.alloc_fails++;
                        u64_stats_update_end(&self->stats.rx.syncp);
                }
                return ret;
        }

        return 0;
}

static struct aq_ring_s *aq_ring_alloc(struct aq_ring_s *self,
                                       struct aq_nic_s *aq_nic)
{
        int err = 0;

        self->buff_ring =
                kcalloc(self->size, sizeof(struct aq_ring_buff_s), GFP_KERNEL);

        if (!self->buff_ring) {
                err = -ENOMEM;
                goto err_exit;
        }
        self->dx_ring = dma_alloc_coherent(aq_nic_get_dev(aq_nic),
                                           self->size * self->dx_size,
                                           &self->dx_ring_pa, GFP_KERNEL);
        if (!self->dx_ring) {
                err = -ENOMEM;
                goto err_exit;
        }

err_exit:
        if (err < 0) {
                aq_ring_free(self);
                self = NULL;
        }

        return self;
}

struct aq_ring_s *aq_ring_tx_alloc(struct aq_ring_s *self,
                                   struct aq_nic_s *aq_nic,
                                   unsigned int idx,
                                   struct aq_nic_cfg_s *aq_nic_cfg)
{
        int err = 0;

        self->aq_nic = aq_nic;
        self->idx = idx;
        self->size = aq_nic_cfg->txds;
        self->dx_size = aq_nic_cfg->aq_hw_caps->txd_size;

        self = aq_ring_alloc(self, aq_nic);
        if (!self) {
                err = -ENOMEM;
                goto err_exit;
        }

err_exit:
        if (err < 0) {
                aq_ring_free(self);
                self = NULL;
        }

        return self;
}

struct aq_ring_s *aq_ring_rx_alloc(struct aq_ring_s *self,
                                   struct aq_nic_s *aq_nic,
                                   unsigned int idx,
                                   struct aq_nic_cfg_s *aq_nic_cfg)
{
        int err = 0;

        self->aq_nic = aq_nic;
        self->idx = idx;
        self->size = aq_nic_cfg->rxds;
        self->dx_size = aq_nic_cfg->aq_hw_caps->rxd_size;
        self->page_order = fls(AQ_CFG_RX_FRAME_MAX / PAGE_SIZE +
                               (AQ_CFG_RX_FRAME_MAX % PAGE_SIZE ? 1 : 0)) - 1;

        if (aq_nic_cfg->rxpageorder > self->page_order)
                self->page_order = aq_nic_cfg->rxpageorder;

        self = aq_ring_alloc(self, aq_nic);
        if (!self) {
                err = -ENOMEM;
                goto err_exit;
        }

err_exit:
        if (err < 0) {
                aq_ring_free(self);
                self = NULL;
        }

        return self;
}

struct aq_ring_s *
aq_ring_hwts_rx_alloc(struct aq_ring_s *self, struct aq_nic_s *aq_nic,
                      unsigned int idx, unsigned int size, unsigned int dx_size)
{
        struct device *dev = aq_nic_get_dev(aq_nic);
        size_t sz = size * dx_size + AQ_CFG_RXDS_DEF;

        memset(self, 0, sizeof(*self));

        self->aq_nic = aq_nic;
        self->idx = idx;
        self->size = size;
        self->dx_size = dx_size;

        self->dx_ring = dma_alloc_coherent(dev, sz, &self->dx_ring_pa,
                                           GFP_KERNEL);
        if (!self->dx_ring) {
                aq_ring_free(self);
                return NULL;
        }

        return self;
}

int aq_ring_init(struct aq_ring_s *self, const enum atl_ring_type ring_type)
{
        self->hw_head = 0;
        self->sw_head = 0;
        self->sw_tail = 0;
        self->ring_type = ring_type;

        if (self->ring_type == ATL_RING_RX)
                u64_stats_init(&self->stats.rx.syncp);
        else
                u64_stats_init(&self->stats.tx.syncp);

        return 0;
}

static inline bool aq_ring_dx_in_range(unsigned int h, unsigned int i,
                                       unsigned int t)
{
        return (h < t) ? ((h < i) && (i < t)) : ((h < i) || (i < t));
}

void aq_ring_update_queue_state(struct aq_ring_s *ring)
{
        if (aq_ring_avail_dx(ring) <= AQ_CFG_SKB_FRAGS_MAX)
                aq_ring_queue_stop(ring);
        else if (aq_ring_avail_dx(ring) > AQ_CFG_RESTART_DESC_THRES)
                aq_ring_queue_wake(ring);
}

void aq_ring_queue_wake(struct aq_ring_s *ring)
{
        struct net_device *ndev = aq_nic_get_ndev(ring->aq_nic);

        if (__netif_subqueue_stopped(ndev,
                                     AQ_NIC_RING2QMAP(ring->aq_nic,
                                                      ring->idx))) {
                netif_wake_subqueue(ndev,
                                    AQ_NIC_RING2QMAP(ring->aq_nic, ring->idx));
                u64_stats_update_begin(&ring->stats.tx.syncp);
                ring->stats.tx.queue_restarts++;
                u64_stats_update_end(&ring->stats.tx.syncp);
        }
}

void aq_ring_queue_stop(struct aq_ring_s *ring)
{
        struct net_device *ndev = aq_nic_get_ndev(ring->aq_nic);

        if (!__netif_subqueue_stopped(ndev,
                                      AQ_NIC_RING2QMAP(ring->aq_nic,
                                                       ring->idx)))
                netif_stop_subqueue(ndev,
                                    AQ_NIC_RING2QMAP(ring->aq_nic, ring->idx));
}

bool aq_ring_tx_clean(struct aq_ring_s *self)
{
        struct device *dev = aq_nic_get_dev(self->aq_nic);
        unsigned int budget;

        for (budget = AQ_CFG_TX_CLEAN_BUDGET;
             budget && self->sw_head != self->hw_head; budget--) {
                struct aq_ring_buff_s *buff = &self->buff_ring[self->sw_head];

                if (likely(buff->is_mapped)) {
                        if (unlikely(buff->is_sop)) {
                                if (!buff->is_eop &&
                                    buff->eop_index != 0xffffU &&
                                    (!aq_ring_dx_in_range(self->sw_head,
                                                buff->eop_index,
                                                self->hw_head)))
                                        break;

                                dma_unmap_single(dev, buff->pa, buff->len,
                                                 DMA_TO_DEVICE);
                        } else {
                                dma_unmap_page(dev, buff->pa, buff->len,
                                               DMA_TO_DEVICE);
                        }
                }

                if (unlikely(buff->is_eop)) {
                        u64_stats_update_begin(&self->stats.tx.syncp);
                        ++self->stats.tx.packets;
                        self->stats.tx.bytes += buff->skb->len;
                        u64_stats_update_end(&self->stats.tx.syncp);

                        dev_kfree_skb_any(buff->skb);
                }
                buff->pa = 0U;
                buff->eop_index = 0xffffU;
                self->sw_head = aq_ring_next_dx(self, self->sw_head);
        }

        return !!budget;
}

static void aq_rx_checksum(struct aq_ring_s *self,
                           struct aq_ring_buff_s *buff,
                           struct sk_buff *skb)
{
        if (!(self->aq_nic->ndev->features & NETIF_F_RXCSUM))
                return;

        if (unlikely(buff->is_cso_err)) {
                u64_stats_update_begin(&self->stats.rx.syncp);
                ++self->stats.rx.errors;
                u64_stats_update_end(&self->stats.rx.syncp);
                skb->ip_summed = CHECKSUM_NONE;
                return;
        }
        if (buff->is_ip_cso) {
                __skb_incr_checksum_unnecessary(skb);
        } else {
                skb->ip_summed = CHECKSUM_NONE;
        }

        if (buff->is_udp_cso || buff->is_tcp_cso)
                __skb_incr_checksum_unnecessary(skb);
}

#define AQ_SKB_ALIGN SKB_DATA_ALIGN(sizeof(struct skb_shared_info))
int aq_ring_rx_clean(struct aq_ring_s *self,
                     struct napi_struct *napi,
                     int *work_done,
                     int budget)
{
        struct net_device *ndev = aq_nic_get_ndev(self->aq_nic);
        bool is_rsc_completed = true;
        int err = 0;

        for (; (self->sw_head != self->hw_head) && budget;
                self->sw_head = aq_ring_next_dx(self, self->sw_head),
                --budget, ++(*work_done)) {
                struct aq_ring_buff_s *buff = &self->buff_ring[self->sw_head];
                bool is_ptp_ring = aq_ptp_ring(self->aq_nic, self);
                struct aq_ring_buff_s *buff_ = NULL;
                struct sk_buff *skb = NULL;
                unsigned int next_ = 0U;
                unsigned int i = 0U;
                u16 hdr_len;

                if (buff->is_cleaned)
                        continue;

                if (!buff->is_eop) {
                        buff_ = buff;
                        do {
                                next_ = buff_->next,
                                buff_ = &self->buff_ring[next_];
                                is_rsc_completed =
                                        aq_ring_dx_in_range(self->sw_head,
                                                            next_,
                                                            self->hw_head);

                                if (unlikely(!is_rsc_completed))
                                        break;

                                buff->is_error |= buff_->is_error;
                                buff->is_cso_err |= buff_->is_cso_err;

                        } while (!buff_->is_eop);

                        if (!is_rsc_completed) {
                                err = 0;
                                goto err_exit;
                        }
                        if (buff->is_error ||
                            (buff->is_lro && buff->is_cso_err)) {
                                buff_ = buff;
                                do {
                                        next_ = buff_->next,
                                        buff_ = &self->buff_ring[next_];

                                        buff_->is_cleaned = true;
                                } while (!buff_->is_eop);

                                u64_stats_update_begin(&self->stats.rx.syncp);
                                ++self->stats.rx.errors;
                                u64_stats_update_end(&self->stats.rx.syncp);
                                continue;
                        }
                }

                if (buff->is_error) {
                        u64_stats_update_begin(&self->stats.rx.syncp);
                        ++self->stats.rx.errors;
                        u64_stats_update_end(&self->stats.rx.syncp);
                        continue;
                }

                dma_sync_single_range_for_cpu(aq_nic_get_dev(self->aq_nic),
                                              buff->rxdata.daddr,
                                              buff->rxdata.pg_off,
                                              buff->len, DMA_FROM_DEVICE);

                skb = napi_alloc_skb(napi, AQ_CFG_RX_HDR_SIZE);
                if (unlikely(!skb)) {
                        u64_stats_update_begin(&self->stats.rx.syncp);
                        self->stats.rx.skb_alloc_fails++;
                        u64_stats_update_end(&self->stats.rx.syncp);
                        err = -ENOMEM;
                        goto err_exit;
                }
                if (is_ptp_ring)
                        buff->len -=
                                aq_ptp_extract_ts(self->aq_nic, skb,
                                                  aq_buf_vaddr(&buff->rxdata),
                                                  buff->len);

                hdr_len = buff->len;
                if (hdr_len > AQ_CFG_RX_HDR_SIZE)
                        hdr_len = eth_get_headlen(skb->dev,
                                                  aq_buf_vaddr(&buff->rxdata),
                                                  AQ_CFG_RX_HDR_SIZE);

                memcpy(__skb_put(skb, hdr_len), aq_buf_vaddr(&buff->rxdata),
                       ALIGN(hdr_len, sizeof(long)));

                if (buff->len - hdr_len > 0) {
                        skb_add_rx_frag(skb, 0, buff->rxdata.page,
                                        buff->rxdata.pg_off + hdr_len,
                                        buff->len - hdr_len,
                                        AQ_CFG_RX_FRAME_MAX);
                        page_ref_inc(buff->rxdata.page);
                }

                if (!buff->is_eop) {
                        buff_ = buff;
                        i = 1U;
                        do {
                                next_ = buff_->next;
                                buff_ = &self->buff_ring[next_];

                                dma_sync_single_range_for_cpu(aq_nic_get_dev(self->aq_nic),
                                                              buff_->rxdata.daddr,
                                                              buff_->rxdata.pg_off,
                                                              buff_->len,
                                                              DMA_FROM_DEVICE);
                                skb_add_rx_frag(skb, i++,
                                                buff_->rxdata.page,
                                                buff_->rxdata.pg_off,
                                                buff_->len,
                                                AQ_CFG_RX_FRAME_MAX);
                                page_ref_inc(buff_->rxdata.page);
                                buff_->is_cleaned = 1;

                                buff->is_ip_cso &= buff_->is_ip_cso;
                                buff->is_udp_cso &= buff_->is_udp_cso;
                                buff->is_tcp_cso &= buff_->is_tcp_cso;
                                buff->is_cso_err |= buff_->is_cso_err;

                        } while (!buff_->is_eop);
                }

                if (buff->is_vlan)
                        __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
                                               buff->vlan_rx_tag);

                skb->protocol = eth_type_trans(skb, ndev);

                aq_rx_checksum(self, buff, skb);

                skb_set_hash(skb, buff->rss_hash,
                             buff->is_hash_l4 ? PKT_HASH_TYPE_L4 :
                             PKT_HASH_TYPE_NONE);
                /* Send all PTP traffic to 0 queue */
                skb_record_rx_queue(skb,
                                    is_ptp_ring ? 0
                                                : AQ_NIC_RING2QMAP(self->aq_nic,
                                                                   self->idx));

                u64_stats_update_begin(&self->stats.rx.syncp);
                ++self->stats.rx.packets;
                self->stats.rx.bytes += skb->len;
                u64_stats_update_end(&self->stats.rx.syncp);

                napi_gro_receive(napi, skb);
        }

err_exit:
        return err;
}

void aq_ring_hwts_rx_clean(struct aq_ring_s *self, struct aq_nic_s *aq_nic)
{
#if IS_REACHABLE(CONFIG_PTP_1588_CLOCK)
        while (self->sw_head != self->hw_head) {
                u64 ns;

                aq_nic->aq_hw_ops->extract_hwts(aq_nic->aq_hw,
                                                self->dx_ring +
                                                (self->sw_head * self->dx_size),
                                                self->dx_size, &ns);
                aq_ptp_tx_hwtstamp(aq_nic, ns);

                self->sw_head = aq_ring_next_dx(self, self->sw_head);
        }
#endif
}

int aq_ring_rx_fill(struct aq_ring_s *self)
{
        unsigned int page_order = self->page_order;
        struct aq_ring_buff_s *buff = NULL;
        int err = 0;
        int i = 0;

        if (aq_ring_avail_dx(self) < min_t(unsigned int, AQ_CFG_RX_REFILL_THRES,
                                           self->size / 2))
                return err;

        for (i = aq_ring_avail_dx(self); i--;
                self->sw_tail = aq_ring_next_dx(self, self->sw_tail)) {
                buff = &self->buff_ring[self->sw_tail];

                buff->flags = 0U;
                buff->len = AQ_CFG_RX_FRAME_MAX;

                err = aq_get_rxpages(self, buff, page_order);
                if (err)
                        goto err_exit;

                buff->pa = aq_buf_daddr(&buff->rxdata);
                buff = NULL;
        }

err_exit:
        return err;
}

void aq_ring_rx_deinit(struct aq_ring_s *self)
{
        if (!self)
                return;

        for (; self->sw_head != self->sw_tail;
                self->sw_head = aq_ring_next_dx(self, self->sw_head)) {
                struct aq_ring_buff_s *buff = &self->buff_ring[self->sw_head];

                aq_free_rxpage(&buff->rxdata, aq_nic_get_dev(self->aq_nic));
        }
}

void aq_ring_free(struct aq_ring_s *self)
{
        if (!self)
                return;

        kfree(self->buff_ring);

        if (self->dx_ring)
                dma_free_coherent(aq_nic_get_dev(self->aq_nic),
                                  self->size * self->dx_size, self->dx_ring,
                                  self->dx_ring_pa);
}

unsigned int aq_ring_fill_stats_data(struct aq_ring_s *self, u64 *data)
{
        unsigned int count;
        unsigned int start;

        if (self->ring_type == ATL_RING_RX) {
                /* This data should mimic aq_ethtool_queue_rx_stat_names structure */
                do {
                        count = 0;
                        start = u64_stats_fetch_begin_irq(&self->stats.rx.syncp);
                        data[count] = self->stats.rx.packets;
                        data[++count] = self->stats.rx.jumbo_packets;
                        data[++count] = self->stats.rx.lro_packets;
                        data[++count] = self->stats.rx.errors;
                        data[++count] = self->stats.rx.alloc_fails;
                        data[++count] = self->stats.rx.skb_alloc_fails;
                        data[++count] = self->stats.rx.polls;
                } while (u64_stats_fetch_retry_irq(&self->stats.rx.syncp, start));
        } else {
                /* This data should mimic aq_ethtool_queue_tx_stat_names structure */
                do {
                        count = 0;
                        start = u64_stats_fetch_begin_irq(&self->stats.tx.syncp);
                        data[count] = self->stats.tx.packets;
                        data[++count] = self->stats.tx.queue_restarts;
                } while (u64_stats_fetch_retry_irq(&self->stats.tx.syncp, start));
        }

        return ++count;
}