// SPDX-License-Identifier: GPL-2.0-only
/****************************************************************************
 * Driver for Solarflare network controllers and boards
 * Copyright 2022 Advanced Micro Devices, Inc.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation, incorporated herein by reference.
 */

#include "tc_counters.h"
#include "tc_encap_actions.h"
#include "mae_counter_format.h"
#include "mae.h"
#include "rx_common.h"

/* Counter-management hashtables */

static const struct rhashtable_params efx_tc_counter_id_ht_params = {
        .key_len        = offsetof(struct efx_tc_counter_index, linkage),
        .key_offset     = 0,
        .head_offset    = offsetof(struct efx_tc_counter_index, linkage),
};

static const struct rhashtable_params efx_tc_counter_ht_params = {
        .key_len        = offsetof(struct efx_tc_counter, linkage),
        .key_offset     = 0,
        .head_offset    = offsetof(struct efx_tc_counter, linkage),
};

static void efx_tc_counter_free(void *ptr, void *__unused)
{
        struct efx_tc_counter *cnt = ptr;

        WARN_ON(!list_empty(&cnt->users));
        /* We'd like to synchronize_rcu() here, but unfortunately we aren't
         * removing the element from the hashtable (it's not clear that's a
         * safe thing to do in an rhashtable_free_and_destroy free_fn), so
         * threads could still be obtaining new pointers to *cnt if they can
         * race against this function at all.
         */
        flush_work(&cnt->work);
        EFX_WARN_ON_PARANOID(spin_is_locked(&cnt->lock));
        kfree(cnt);
}

static void efx_tc_counter_id_free(void *ptr, void *__unused)
{
        struct efx_tc_counter_index *ctr = ptr;

        WARN_ON(refcount_read(&ctr->ref));
        kfree(ctr);
}

int efx_tc_init_counters(struct efx_nic *efx)
{
        int rc;

        rc = rhashtable_init(&efx->tc->counter_id_ht, &efx_tc_counter_id_ht_params);
        if (rc < 0)
                goto fail_counter_id_ht;
        rc = rhashtable_init(&efx->tc->counter_ht, &efx_tc_counter_ht_params);
        if (rc < 0)
                goto fail_counter_ht;
        return 0;
fail_counter_ht:
        rhashtable_destroy(&efx->tc->counter_id_ht);
fail_counter_id_ht:
        return rc;
}

/* Only call this in init failure teardown.
 * Normal exit should fini instead as there may be entries in the table.
 */
void efx_tc_destroy_counters(struct efx_nic *efx)
{
        rhashtable_destroy(&efx->tc->counter_ht);
        rhashtable_destroy(&efx->tc->counter_id_ht);
}

void efx_tc_fini_counters(struct efx_nic *efx)
{
        rhashtable_free_and_destroy(&efx->tc->counter_id_ht, efx_tc_counter_id_free, NULL);
        rhashtable_free_and_destroy(&efx->tc->counter_ht, efx_tc_counter_free, NULL);
}

static void efx_tc_counter_work(struct work_struct *work)
{
        struct efx_tc_counter *cnt = container_of(work, struct efx_tc_counter, work);
        struct efx_tc_encap_action *encap;
        struct efx_tc_action_set *act;
        unsigned long touched;
        struct neighbour *n;

        spin_lock_bh(&cnt->lock);
        touched = READ_ONCE(cnt->touched);

        list_for_each_entry(act, &cnt->users, count_user) {
                encap = act->encap_md;
                if (!encap)
                        continue;
                if (!encap->neigh) /* can't happen */
                        continue;
                if (time_after_eq(encap->neigh->used, touched))
                        continue;
                encap->neigh->used = touched;
                /* We have passed traffic using this ARP entry, so
                 * indicate to the ARP cache that it's still active
                 */
                if (encap->neigh->dst_ip)
                        n = neigh_lookup(&arp_tbl, &encap->neigh->dst_ip,
                                         encap->neigh->egdev);
                else
#if IS_ENABLED(CONFIG_IPV6)
                        n = neigh_lookup(ipv6_stub->nd_tbl,
                                         &encap->neigh->dst_ip6,
                                         encap->neigh->egdev);
#else
                        n = NULL;
#endif
                if (!n)
                        continue;

                neigh_event_send(n, NULL);
                neigh_release(n);
        }
        spin_unlock_bh(&cnt->lock);
}

/* Counter allocation */

struct efx_tc_counter *efx_tc_flower_allocate_counter(struct efx_nic *efx,
                                                      int type)
{
        struct efx_tc_counter *cnt;
        int rc, rc2;

        cnt = kzalloc_obj(*cnt, GFP_USER);
        if (!cnt)
                return ERR_PTR(-ENOMEM);

        spin_lock_init(&cnt->lock);
        INIT_WORK(&cnt->work, efx_tc_counter_work);
        cnt->touched = jiffies;
        cnt->type = type;

        rc = efx_mae_allocate_counter(efx, cnt);
        if (rc)
                goto fail1;
        INIT_LIST_HEAD(&cnt->users);
        rc = rhashtable_insert_fast(&efx->tc->counter_ht, &cnt->linkage,
                                    efx_tc_counter_ht_params);
        if (rc)
                goto fail2;
        return cnt;
fail2:
        /* If we get here, it implies that we couldn't insert into the table,
         * which in turn probably means that the fw_id was already taken.
         * In that case, it's unclear whether we really 'own' the fw_id; but
         * the firmware seemed to think we did, so it's proper to free it.
         */
        rc2 = efx_mae_free_counter(efx, cnt);
        if (rc2)
                netif_warn(efx, hw, efx->net_dev,
                           "Failed to free MAE counter %u, rc %d\n",
                           cnt->fw_id, rc2);
fail1:
        kfree(cnt);
        return ERR_PTR(rc > 0 ? -EIO : rc);
}

void efx_tc_flower_release_counter(struct efx_nic *efx,
                                   struct efx_tc_counter *cnt)
{
        int rc;

        rhashtable_remove_fast(&efx->tc->counter_ht, &cnt->linkage,
                               efx_tc_counter_ht_params);
        rc = efx_mae_free_counter(efx, cnt);
        if (rc)
                netif_warn(efx, hw, efx->net_dev,
                           "Failed to free MAE counter %u, rc %d\n",
                           cnt->fw_id, rc);
        WARN_ON(!list_empty(&cnt->users));
        /* This doesn't protect counter updates coming in arbitrarily long
         * after we deleted the counter.  The RCU just ensures that we won't
         * free the counter while another thread has a pointer to it.
         * Ensuring we don't update the wrong counter if the ID gets re-used
         * is handled by the generation count.
         */
        synchronize_rcu();
        flush_work(&cnt->work);
        EFX_WARN_ON_PARANOID(spin_is_locked(&cnt->lock));
        kfree(cnt);
}

static struct efx_tc_counter *efx_tc_flower_find_counter_by_fw_id(
                                struct efx_nic *efx, int type, u32 fw_id)
{
        struct efx_tc_counter key = {};

        key.fw_id = fw_id;
        key.type = type;

        return rhashtable_lookup_fast(&efx->tc->counter_ht, &key,
                                      efx_tc_counter_ht_params);
}

/* TC cookie to counter mapping */

void efx_tc_flower_put_counter_index(struct efx_nic *efx,
                                     struct efx_tc_counter_index *ctr)
{
        if (!refcount_dec_and_test(&ctr->ref))
                return; /* still in use */
        rhashtable_remove_fast(&efx->tc->counter_id_ht, &ctr->linkage,
                               efx_tc_counter_id_ht_params);
        efx_tc_flower_release_counter(efx, ctr->cnt);
        kfree(ctr);
}

struct efx_tc_counter_index *efx_tc_flower_get_counter_index(
                                struct efx_nic *efx, unsigned long cookie,
                                enum efx_tc_counter_type type)
{
        struct efx_tc_counter_index *ctr, *old;
        struct efx_tc_counter *cnt;

        ctr = kzalloc_obj(*ctr, GFP_USER);
        if (!ctr)
                return ERR_PTR(-ENOMEM);
        ctr->cookie = cookie;
        old = rhashtable_lookup_get_insert_fast(&efx->tc->counter_id_ht,
                                                &ctr->linkage,
                                                efx_tc_counter_id_ht_params);
        if (old) {
                /* don't need our new entry */
                kfree(ctr);
                if (IS_ERR(old)) /* oh dear, it's actually an error */
                        return ERR_CAST(old);
                if (!refcount_inc_not_zero(&old->ref))
                        return ERR_PTR(-EAGAIN);
                /* existing entry found */
                ctr = old;
        } else {
                cnt = efx_tc_flower_allocate_counter(efx, type);
                if (IS_ERR(cnt)) {
                        rhashtable_remove_fast(&efx->tc->counter_id_ht,
                                               &ctr->linkage,
                                               efx_tc_counter_id_ht_params);
                        kfree(ctr);
                        return ERR_CAST(cnt);
                }
                ctr->cnt = cnt;
                refcount_set(&ctr->ref, 1);
        }
        return ctr;
}

struct efx_tc_counter_index *efx_tc_flower_find_counter_index(
                                struct efx_nic *efx, unsigned long cookie)
{
        struct efx_tc_counter_index key = {};

        key.cookie = cookie;
        return rhashtable_lookup_fast(&efx->tc->counter_id_ht, &key,
                                      efx_tc_counter_id_ht_params);
}

/* TC Channel.  Counter updates are delivered on this channel's RXQ. */

static void efx_tc_handle_no_channel(struct efx_nic *efx)
{
        netif_warn(efx, drv, efx->net_dev,
                   "MAE counters require MSI-X and 1 additional interrupt vector.\n");
}

static int efx_tc_probe_channel(struct efx_channel *channel)
{
        struct efx_rx_queue *rx_queue = &channel->rx_queue;

        channel->irq_moderation_us = 0;
        rx_queue->core_index = 0;

        INIT_WORK(&rx_queue->grant_work, efx_mae_counters_grant_credits);

        return 0;
}

static int efx_tc_start_channel(struct efx_channel *channel)
{
        struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel);
        struct efx_nic *efx = channel->efx;

        return efx_mae_start_counters(efx, rx_queue);
}

static void efx_tc_stop_channel(struct efx_channel *channel)
{
        struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel);
        struct efx_nic *efx = channel->efx;
        int rc;

        rc = efx_mae_stop_counters(efx, rx_queue);
        if (rc)
                netif_warn(efx, drv, efx->net_dev,
                           "Failed to stop MAE counters streaming, rc=%d.\n",
                           rc);
        rx_queue->grant_credits = false;
        flush_work(&rx_queue->grant_work);
}

static void efx_tc_remove_channel(struct efx_channel *channel)
{
}

static void efx_tc_get_channel_name(struct efx_channel *channel,
                                    char *buf, size_t len)
{
        snprintf(buf, len, "%s-mae", channel->efx->name);
}

static void efx_tc_counter_update(struct efx_nic *efx,
                                  enum efx_tc_counter_type counter_type,
                                  u32 counter_idx, u64 packets, u64 bytes,
                                  u32 mark)
{
        struct efx_tc_counter *cnt;

        rcu_read_lock(); /* Protect against deletion of 'cnt' */
        cnt = efx_tc_flower_find_counter_by_fw_id(efx, counter_type, counter_idx);
        if (!cnt) {
                /* This can legitimately happen when a counter is removed,
                 * with updates for the counter still in-flight; however this
                 * should be an infrequent occurrence.
                 */
                if (net_ratelimit())
                        netif_dbg(efx, drv, efx->net_dev,
                                  "Got update for unwanted MAE counter %u type %u\n",
                                  counter_idx, counter_type);
                goto out;
        }

        spin_lock_bh(&cnt->lock);
        if ((s32)mark - (s32)cnt->gen < 0) {
                /* This counter update packet is from before the counter was
                 * allocated; thus it must be for a previous counter with
                 * the same ID that has since been freed, and it should be
                 * ignored.
                 */
        } else {
                /* Update latest seen generation count.  This ensures that
                 * even a long-lived counter won't start getting ignored if
                 * the generation count wraps around, unless it somehow
                 * manages to go 1<<31 generations without an update.
                 */
                cnt->gen = mark;
                /* update counter values */
                cnt->packets += packets;
                cnt->bytes += bytes;
                cnt->touched = jiffies;
        }
        spin_unlock_bh(&cnt->lock);
        schedule_work(&cnt->work);
out:
        rcu_read_unlock();
}

static void efx_tc_rx_version_1(struct efx_nic *efx, const u8 *data, u32 mark)
{
        u16 n_counters, i;

        /* Header format:
         * + |   0    |   1    |   2    |   3    |
         * 0 |version |         reserved         |
         * 4 |    seq_index    |   n_counters    |
         */

        n_counters = le16_to_cpu(*(const __le16 *)(data + 6));

        /* Counter update entry format:
         * | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | a | b | c | d | e | f |
         * |  counter_idx  |     packet_count      |      byte_count       |
         */
        for (i = 0; i < n_counters; i++) {
                const void *entry = data + 8 + 16 * i;
                u64 packet_count, byte_count;
                u32 counter_idx;

                counter_idx = le32_to_cpu(*(const __le32 *)entry);
                packet_count = le32_to_cpu(*(const __le32 *)(entry + 4)) |
                               ((u64)le16_to_cpu(*(const __le16 *)(entry + 8)) << 32);
                byte_count = le16_to_cpu(*(const __le16 *)(entry + 10)) |
                             ((u64)le32_to_cpu(*(const __le32 *)(entry + 12)) << 16);
                efx_tc_counter_update(efx, EFX_TC_COUNTER_TYPE_AR, counter_idx,
                                      packet_count, byte_count, mark);
        }
}

#define TCV2_HDR_PTR(pkt, field)                                                \
        ((void)BUILD_BUG_ON_ZERO(ERF_SC_PACKETISER_HEADER_##field##_LBN & 7),   \
         (pkt) + ERF_SC_PACKETISER_HEADER_##field##_LBN / 8)
#define TCV2_HDR_BYTE(pkt, field)                                               \
        ((void)BUILD_BUG_ON_ZERO(ERF_SC_PACKETISER_HEADER_##field##_WIDTH != 8),\
         *TCV2_HDR_PTR(pkt, field))
#define TCV2_HDR_WORD(pkt, field)                                               \
        ((void)BUILD_BUG_ON_ZERO(ERF_SC_PACKETISER_HEADER_##field##_WIDTH != 16),\
         (void)BUILD_BUG_ON_ZERO(ERF_SC_PACKETISER_HEADER_##field##_LBN & 15),  \
         *(__force const __le16 *)TCV2_HDR_PTR(pkt, field))
#define TCV2_PKT_PTR(pkt, poff, i, field)                                       \
        ((void)BUILD_BUG_ON_ZERO(ERF_SC_PACKETISER_PAYLOAD_##field##_LBN & 7),  \
         (pkt) + ERF_SC_PACKETISER_PAYLOAD_##field##_LBN/8 + poff +             \
         i * ER_RX_SL_PACKETISER_PAYLOAD_WORD_SIZE)

/* Read a little-endian 48-bit field with 16-bit alignment */
static u64 efx_tc_read48(const __le16 *field)
{
        u64 out = 0;
        int i;

        for (i = 0; i < 3; i++)
                out |= (u64)le16_to_cpu(field[i]) << (i * 16);
        return out;
}

static enum efx_tc_counter_type efx_tc_rx_version_2(struct efx_nic *efx,
                                                    const u8 *data, u32 mark)
{
        u8 payload_offset, header_offset, ident;
        enum efx_tc_counter_type type;
        u16 n_counters, i;

        ident = TCV2_HDR_BYTE(data, IDENTIFIER);
        switch (ident) {
        case ERF_SC_PACKETISER_HEADER_IDENTIFIER_AR:
                type = EFX_TC_COUNTER_TYPE_AR;
                break;
        case ERF_SC_PACKETISER_HEADER_IDENTIFIER_CT:
                type = EFX_TC_COUNTER_TYPE_CT;
                break;
        case ERF_SC_PACKETISER_HEADER_IDENTIFIER_OR:
                type = EFX_TC_COUNTER_TYPE_OR;
                break;
        default:
                if (net_ratelimit())
                        netif_err(efx, drv, efx->net_dev,
                                  "ignored v2 MAE counter packet (bad identifier %u"
                                  "), counters may be inaccurate\n", ident);
                return EFX_TC_COUNTER_TYPE_MAX;
        }
        header_offset = TCV2_HDR_BYTE(data, HEADER_OFFSET);
        /* mae_counter_format.h implies that this offset is fixed, since it
         * carries on with SOP-based LBNs for the fields in this header
         */
        if (header_offset != ERF_SC_PACKETISER_HEADER_HEADER_OFFSET_DEFAULT) {
                if (net_ratelimit())
                        netif_err(efx, drv, efx->net_dev,
                                  "choked on v2 MAE counter packet (bad header_offset %u"
                                  "), counters may be inaccurate\n", header_offset);
                return EFX_TC_COUNTER_TYPE_MAX;
        }
        payload_offset = TCV2_HDR_BYTE(data, PAYLOAD_OFFSET);
        n_counters = le16_to_cpu(TCV2_HDR_WORD(data, COUNT));

        for (i = 0; i < n_counters; i++) {
                const void *counter_idx_p, *packet_count_p, *byte_count_p;
                u64 packet_count, byte_count;
                u32 counter_idx;

                /* 24-bit field with 32-bit alignment */
                counter_idx_p = TCV2_PKT_PTR(data, payload_offset, i, COUNTER_INDEX);
                BUILD_BUG_ON(ERF_SC_PACKETISER_PAYLOAD_COUNTER_INDEX_WIDTH != 24);
                BUILD_BUG_ON(ERF_SC_PACKETISER_PAYLOAD_COUNTER_INDEX_LBN & 31);
                counter_idx = le32_to_cpu(*(const __le32 *)counter_idx_p) & 0xffffff;
                /* 48-bit field with 16-bit alignment */
                packet_count_p = TCV2_PKT_PTR(data, payload_offset, i, PACKET_COUNT);
                BUILD_BUG_ON(ERF_SC_PACKETISER_PAYLOAD_PACKET_COUNT_WIDTH != 48);
                BUILD_BUG_ON(ERF_SC_PACKETISER_PAYLOAD_PACKET_COUNT_LBN & 15);
                packet_count = efx_tc_read48((const __le16 *)packet_count_p);
                /* 48-bit field with 16-bit alignment */
                byte_count_p = TCV2_PKT_PTR(data, payload_offset, i, BYTE_COUNT);
                BUILD_BUG_ON(ERF_SC_PACKETISER_PAYLOAD_BYTE_COUNT_WIDTH != 48);
                BUILD_BUG_ON(ERF_SC_PACKETISER_PAYLOAD_BYTE_COUNT_LBN & 15);
                byte_count = efx_tc_read48((const __le16 *)byte_count_p);

                if (type == EFX_TC_COUNTER_TYPE_CT) {
                        /* CT counters are 1-bit saturating counters to update
                         * the lastuse time in CT stats. A received CT counter
                         * should have packet counter to 0 and only LSB bit on
                         * in byte counter.
                         */
                        if (packet_count || byte_count != 1)
                                netdev_warn_once(efx->net_dev,
                                                 "CT counter with inconsistent state (%llu, %llu)\n",
                                                 packet_count, byte_count);
                        /* Do not increment the driver's byte counter */
                        byte_count = 0;
                }

                efx_tc_counter_update(efx, type, counter_idx, packet_count,
                                      byte_count, mark);
        }
        return type;
}

/* We always swallow the packet, whether successful or not, since it's not
 * a network packet and shouldn't ever be forwarded to the stack.
 * @mark is the generation count for counter allocations.
 */
static bool efx_tc_rx(struct efx_rx_queue *rx_queue, u32 mark)
{
        struct efx_channel *channel = efx_rx_queue_channel(rx_queue);
        struct efx_rx_buffer *rx_buf = efx_rx_buffer(rx_queue,
                                                     channel->rx_pkt_index);
        const u8 *data = efx_rx_buf_va(rx_buf);
        struct efx_nic *efx = rx_queue->efx;
        enum efx_tc_counter_type type;
        u8 version;

        /* version is always first byte of packet */
        version = *data;
        switch (version) {
        case 1:
                type = EFX_TC_COUNTER_TYPE_AR;
                efx_tc_rx_version_1(efx, data, mark);
                break;
        case ERF_SC_PACKETISER_HEADER_VERSION_VALUE: // 2
                type = efx_tc_rx_version_2(efx, data, mark);
                break;
        default:
                if (net_ratelimit())
                        netif_err(efx, drv, efx->net_dev,
                                  "choked on MAE counter packet (bad version %u"
                                  "); counters may be inaccurate\n",
                                  version);
                goto out;
        }

        if (type < EFX_TC_COUNTER_TYPE_MAX) {
                /* Update seen_gen unconditionally, to avoid a missed wakeup if
                 * we race with efx_mae_stop_counters().
                 */
                efx->tc->seen_gen[type] = mark;
                if (efx->tc->flush_counters &&
                    (s32)(efx->tc->flush_gen[type] - mark) <= 0)
                        wake_up(&efx->tc->flush_wq);
        }
out:
        efx_free_rx_buffers(rx_queue, rx_buf, 1);
        channel->rx_pkt_n_frags = 0;
        return true;
}

const struct efx_channel_type efx_tc_channel_type = {
        .handle_no_channel      = efx_tc_handle_no_channel,
        .pre_probe              = efx_tc_probe_channel,
        .start                  = efx_tc_start_channel,
        .stop                   = efx_tc_stop_channel,
        .post_remove            = efx_tc_remove_channel,
        .get_name               = efx_tc_get_channel_name,
        .receive_raw            = efx_tc_rx,
        .keep_eventq            = true,
};