/****************************************************************************
 * Driver for Solarflare Solarstorm network controllers and boards
 * Copyright 2005-2010 Solarflare Communications 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 <linux/in.h>
#include <net/ip.h>
#include "efx.h"
#include "filter.h"
#include "io.h"
#include "nic.h"
#include "regs.h"

/* "Fudge factors" - difference between programmed value and actual depth.
 * Due to pipelined implementation we need to program H/W with a value that
 * is larger than the hop limit we want.
 */
#define FILTER_CTL_SRCH_FUDGE_WILD 3
#define FILTER_CTL_SRCH_FUDGE_FULL 1

/* Hard maximum hop limit.  Hardware will time-out beyond 200-something.
 * We also need to avoid infinite loops in efx_filter_search() when the
 * table is full.
 */
#define FILTER_CTL_SRCH_MAX 200

/* Don't try very hard to find space for performance hints, as this is
 * counter-productive. */
#define FILTER_CTL_SRCH_HINT_MAX 5

enum efx_filter_table_id {
        EFX_FILTER_TABLE_RX_IP = 0,
        EFX_FILTER_TABLE_RX_MAC,
        EFX_FILTER_TABLE_RX_DEF,
        EFX_FILTER_TABLE_TX_MAC,
        EFX_FILTER_TABLE_COUNT,
};

enum efx_filter_index {
        EFX_FILTER_INDEX_UC_DEF,
        EFX_FILTER_INDEX_MC_DEF,
        EFX_FILTER_SIZE_RX_DEF,
};

struct efx_filter_table {
        enum efx_filter_table_id id;
        u32             offset;         /* address of table relative to BAR */
        unsigned        size;           /* number of entries */
        unsigned        step;           /* step between entries */
        unsigned        used;           /* number currently used */
        unsigned long   *used_bitmap;
        struct efx_filter_spec *spec;
        unsigned        search_depth[EFX_FILTER_TYPE_COUNT];
};

struct efx_filter_state {
        spinlock_t      lock;
        struct efx_filter_table table[EFX_FILTER_TABLE_COUNT];
#ifdef CONFIG_RFS_ACCEL
        u32             *rps_flow_id;
        unsigned        rps_expire_index;
#endif
};

static void efx_filter_table_clear_entry(struct efx_nic *efx,
                                         struct efx_filter_table *table,
                                         unsigned int filter_idx);

/* The filter hash function is LFSR polynomial x^16 + x^3 + 1 of a 32-bit
 * key derived from the n-tuple.  The initial LFSR state is 0xffff. */
static u16 efx_filter_hash(u32 key)
{
        u16 tmp;

        /* First 16 rounds */
        tmp = 0x1fff ^ key >> 16;
        tmp = tmp ^ tmp >> 3 ^ tmp >> 6;
        tmp = tmp ^ tmp >> 9;
        /* Last 16 rounds */
        tmp = tmp ^ tmp << 13 ^ key;
        tmp = tmp ^ tmp >> 3 ^ tmp >> 6;
        return tmp ^ tmp >> 9;
}

/* To allow for hash collisions, filter search continues at these
 * increments from the first possible entry selected by the hash. */
static u16 efx_filter_increment(u32 key)
{
        return key * 2 - 1;
}

static enum efx_filter_table_id
efx_filter_spec_table_id(const struct efx_filter_spec *spec)
{
        BUILD_BUG_ON(EFX_FILTER_TABLE_RX_IP != (EFX_FILTER_TCP_FULL >> 2));
        BUILD_BUG_ON(EFX_FILTER_TABLE_RX_IP != (EFX_FILTER_TCP_WILD >> 2));
        BUILD_BUG_ON(EFX_FILTER_TABLE_RX_IP != (EFX_FILTER_UDP_FULL >> 2));
        BUILD_BUG_ON(EFX_FILTER_TABLE_RX_IP != (EFX_FILTER_UDP_WILD >> 2));
        BUILD_BUG_ON(EFX_FILTER_TABLE_RX_MAC != (EFX_FILTER_MAC_FULL >> 2));
        BUILD_BUG_ON(EFX_FILTER_TABLE_RX_MAC != (EFX_FILTER_MAC_WILD >> 2));
        BUILD_BUG_ON(EFX_FILTER_TABLE_TX_MAC != EFX_FILTER_TABLE_RX_MAC + 2);
        EFX_BUG_ON_PARANOID(spec->type == EFX_FILTER_UNSPEC);
        return (spec->type >> 2) + ((spec->flags & EFX_FILTER_FLAG_TX) ? 2 : 0);
}

static struct efx_filter_table *
efx_filter_spec_table(struct efx_filter_state *state,
                      const struct efx_filter_spec *spec)
{
        if (spec->type == EFX_FILTER_UNSPEC)
                return NULL;
        else
                return &state->table[efx_filter_spec_table_id(spec)];
}

static void efx_filter_table_reset_search_depth(struct efx_filter_table *table)
{
        memset(table->search_depth, 0, sizeof(table->search_depth));
}

static void efx_filter_push_rx_config(struct efx_nic *efx)
{
        struct efx_filter_state *state = efx->filter_state;
        struct efx_filter_table *table;
        efx_oword_t filter_ctl;

        efx_reado(efx, &filter_ctl, FR_BZ_RX_FILTER_CTL);

        table = &state->table[EFX_FILTER_TABLE_RX_IP];
        EFX_SET_OWORD_FIELD(filter_ctl, FRF_BZ_TCP_FULL_SRCH_LIMIT,
                            table->search_depth[EFX_FILTER_TCP_FULL] +
                            FILTER_CTL_SRCH_FUDGE_FULL);
        EFX_SET_OWORD_FIELD(filter_ctl, FRF_BZ_TCP_WILD_SRCH_LIMIT,
                            table->search_depth[EFX_FILTER_TCP_WILD] +
                            FILTER_CTL_SRCH_FUDGE_WILD);
        EFX_SET_OWORD_FIELD(filter_ctl, FRF_BZ_UDP_FULL_SRCH_LIMIT,
                            table->search_depth[EFX_FILTER_UDP_FULL] +
                            FILTER_CTL_SRCH_FUDGE_FULL);
        EFX_SET_OWORD_FIELD(filter_ctl, FRF_BZ_UDP_WILD_SRCH_LIMIT,
                            table->search_depth[EFX_FILTER_UDP_WILD] +
                            FILTER_CTL_SRCH_FUDGE_WILD);

        table = &state->table[EFX_FILTER_TABLE_RX_MAC];
        if (table->size) {
                EFX_SET_OWORD_FIELD(
                        filter_ctl, FRF_CZ_ETHERNET_FULL_SEARCH_LIMIT,
                        table->search_depth[EFX_FILTER_MAC_FULL] +
                        FILTER_CTL_SRCH_FUDGE_FULL);
                EFX_SET_OWORD_FIELD(
                        filter_ctl, FRF_CZ_ETHERNET_WILDCARD_SEARCH_LIMIT,
                        table->search_depth[EFX_FILTER_MAC_WILD] +
                        FILTER_CTL_SRCH_FUDGE_WILD);
        }

        table = &state->table[EFX_FILTER_TABLE_RX_DEF];
        if (table->size) {
                EFX_SET_OWORD_FIELD(
                        filter_ctl, FRF_CZ_UNICAST_NOMATCH_Q_ID,
                        table->spec[EFX_FILTER_INDEX_UC_DEF].dmaq_id);
                EFX_SET_OWORD_FIELD(
                        filter_ctl, FRF_CZ_UNICAST_NOMATCH_RSS_ENABLED,
                        !!(table->spec[EFX_FILTER_INDEX_UC_DEF].flags &
                           EFX_FILTER_FLAG_RX_RSS));
                EFX_SET_OWORD_FIELD(
                        filter_ctl, FRF_CZ_MULTICAST_NOMATCH_Q_ID,
                        table->spec[EFX_FILTER_INDEX_MC_DEF].dmaq_id);
                EFX_SET_OWORD_FIELD(
                        filter_ctl, FRF_CZ_MULTICAST_NOMATCH_RSS_ENABLED,
                        !!(table->spec[EFX_FILTER_INDEX_MC_DEF].flags &
                           EFX_FILTER_FLAG_RX_RSS));

                /* There is a single bit to enable RX scatter for all
                 * unmatched packets.  Only set it if scatter is
                 * enabled in both filter specs.
                 */
                EFX_SET_OWORD_FIELD(
                        filter_ctl, FRF_BZ_SCATTER_ENBL_NO_MATCH_Q,
                        !!(table->spec[EFX_FILTER_INDEX_UC_DEF].flags &
                           table->spec[EFX_FILTER_INDEX_MC_DEF].flags &
                           EFX_FILTER_FLAG_RX_SCATTER));
        } else if (efx_nic_rev(efx) >= EFX_REV_FALCON_B0) {
                /* We don't expose 'default' filters because unmatched
                 * packets always go to the queue number found in the
                 * RSS table.  But we still need to set the RX scatter
                 * bit here.
                 */
                EFX_SET_OWORD_FIELD(
                        filter_ctl, FRF_BZ_SCATTER_ENBL_NO_MATCH_Q,
                        efx->rx_scatter);
        }

        efx_writeo(efx, &filter_ctl, FR_BZ_RX_FILTER_CTL);
}

static void efx_filter_push_tx_limits(struct efx_nic *efx)
{
        struct efx_filter_state *state = efx->filter_state;
        struct efx_filter_table *table;
        efx_oword_t tx_cfg;

        efx_reado(efx, &tx_cfg, FR_AZ_TX_CFG);

        table = &state->table[EFX_FILTER_TABLE_TX_MAC];
        if (table->size) {
                EFX_SET_OWORD_FIELD(
                        tx_cfg, FRF_CZ_TX_ETH_FILTER_FULL_SEARCH_RANGE,
                        table->search_depth[EFX_FILTER_MAC_FULL] +
                        FILTER_CTL_SRCH_FUDGE_FULL);
                EFX_SET_OWORD_FIELD(
                        tx_cfg, FRF_CZ_TX_ETH_FILTER_WILD_SEARCH_RANGE,
                        table->search_depth[EFX_FILTER_MAC_WILD] +
                        FILTER_CTL_SRCH_FUDGE_WILD);
        }

        efx_writeo(efx, &tx_cfg, FR_AZ_TX_CFG);
}

static inline void __efx_filter_set_ipv4(struct efx_filter_spec *spec,
                                         __be32 host1, __be16 port1,
                                         __be32 host2, __be16 port2)
{
        spec->data[0] = ntohl(host1) << 16 | ntohs(port1);
        spec->data[1] = ntohs(port2) << 16 | ntohl(host1) >> 16;
        spec->data[2] = ntohl(host2);
}

static inline void __efx_filter_get_ipv4(const struct efx_filter_spec *spec,
                                         __be32 *host1, __be16 *port1,
                                         __be32 *host2, __be16 *port2)
{
        *host1 = htonl(spec->data[0] >> 16 | spec->data[1] << 16);
        *port1 = htons(spec->data[0]);
        *host2 = htonl(spec->data[2]);
        *port2 = htons(spec->data[1] >> 16);
}

/**
 * efx_filter_set_ipv4_local - specify IPv4 host, transport protocol and port
 * @spec: Specification to initialise
 * @proto: Transport layer protocol number
 * @host: Local host address (network byte order)
 * @port: Local port (network byte order)
 */
int efx_filter_set_ipv4_local(struct efx_filter_spec *spec, u8 proto,
                              __be32 host, __be16 port)
{
        __be32 host1;
        __be16 port1;

        EFX_BUG_ON_PARANOID(!(spec->flags & EFX_FILTER_FLAG_RX));

        /* This cannot currently be combined with other filtering */
        if (spec->type != EFX_FILTER_UNSPEC)
                return -EPROTONOSUPPORT;

        if (port == 0)
                return -EINVAL;

        switch (proto) {
        case IPPROTO_TCP:
                spec->type = EFX_FILTER_TCP_WILD;
                break;
        case IPPROTO_UDP:
                spec->type = EFX_FILTER_UDP_WILD;
                break;
        default:
                return -EPROTONOSUPPORT;
        }

        /* Filter is constructed in terms of source and destination,
         * with the odd wrinkle that the ports are swapped in a UDP
         * wildcard filter.  We need to convert from local and remote
         * (= zero for wildcard) addresses.
         */
        host1 = 0;
        if (proto != IPPROTO_UDP) {
                port1 = 0;
        } else {
                port1 = port;
                port = 0;
        }

        __efx_filter_set_ipv4(spec, host1, port1, host, port);
        return 0;
}

int efx_filter_get_ipv4_local(const struct efx_filter_spec *spec,
                              u8 *proto, __be32 *host, __be16 *port)
{
        __be32 host1;
        __be16 port1;

        switch (spec->type) {
        case EFX_FILTER_TCP_WILD:
                *proto = IPPROTO_TCP;
                __efx_filter_get_ipv4(spec, &host1, &port1, host, port);
                return 0;
        case EFX_FILTER_UDP_WILD:
                *proto = IPPROTO_UDP;
                __efx_filter_get_ipv4(spec, &host1, port, host, &port1);
                return 0;
        default:
                return -EINVAL;
        }
}

/**
 * efx_filter_set_ipv4_full - specify IPv4 hosts, transport protocol and ports
 * @spec: Specification to initialise
 * @proto: Transport layer protocol number
 * @host: Local host address (network byte order)
 * @port: Local port (network byte order)
 * @rhost: Remote host address (network byte order)
 * @rport: Remote port (network byte order)
 */
int efx_filter_set_ipv4_full(struct efx_filter_spec *spec, u8 proto,
                             __be32 host, __be16 port,
                             __be32 rhost, __be16 rport)
{
        EFX_BUG_ON_PARANOID(!(spec->flags & EFX_FILTER_FLAG_RX));

        /* This cannot currently be combined with other filtering */
        if (spec->type != EFX_FILTER_UNSPEC)
                return -EPROTONOSUPPORT;

        if (port == 0 || rport == 0)
                return -EINVAL;

        switch (proto) {
        case IPPROTO_TCP:
                spec->type = EFX_FILTER_TCP_FULL;
                break;
        case IPPROTO_UDP:
                spec->type = EFX_FILTER_UDP_FULL;
                break;
        default:
                return -EPROTONOSUPPORT;
        }

        __efx_filter_set_ipv4(spec, rhost, rport, host, port);
        return 0;
}

int efx_filter_get_ipv4_full(const struct efx_filter_spec *spec,
                             u8 *proto, __be32 *host, __be16 *port,
                             __be32 *rhost, __be16 *rport)
{
        switch (spec->type) {
        case EFX_FILTER_TCP_FULL:
                *proto = IPPROTO_TCP;
                break;
        case EFX_FILTER_UDP_FULL:
                *proto = IPPROTO_UDP;
                break;
        default:
                return -EINVAL;
        }

        __efx_filter_get_ipv4(spec, rhost, rport, host, port);
        return 0;
}

/**
 * efx_filter_set_eth_local - specify local Ethernet address and optional VID
 * @spec: Specification to initialise
 * @vid: VLAN ID to match, or %EFX_FILTER_VID_UNSPEC
 * @addr: Local Ethernet MAC address
 */
int efx_filter_set_eth_local(struct efx_filter_spec *spec,
                             u16 vid, const u8 *addr)
{
        EFX_BUG_ON_PARANOID(!(spec->flags &
                              (EFX_FILTER_FLAG_RX | EFX_FILTER_FLAG_TX)));

        /* This cannot currently be combined with other filtering */
        if (spec->type != EFX_FILTER_UNSPEC)
                return -EPROTONOSUPPORT;

        if (vid == EFX_FILTER_VID_UNSPEC) {
                spec->type = EFX_FILTER_MAC_WILD;
                spec->data[0] = 0;
        } else {
                spec->type = EFX_FILTER_MAC_FULL;
                spec->data[0] = vid;
        }

        spec->data[1] = addr[2] << 24 | addr[3] << 16 | addr[4] << 8 | addr[5];
        spec->data[2] = addr[0] << 8 | addr[1];
        return 0;
}

/**
 * efx_filter_set_uc_def - specify matching otherwise-unmatched unicast
 * @spec: Specification to initialise
 */
int efx_filter_set_uc_def(struct efx_filter_spec *spec)
{
        EFX_BUG_ON_PARANOID(!(spec->flags &
                              (EFX_FILTER_FLAG_RX | EFX_FILTER_FLAG_TX)));

        if (spec->type != EFX_FILTER_UNSPEC)
                return -EINVAL;

        spec->type = EFX_FILTER_UC_DEF;
        memset(spec->data, 0, sizeof(spec->data)); /* ensure equality */
        return 0;
}

/**
 * efx_filter_set_mc_def - specify matching otherwise-unmatched multicast
 * @spec: Specification to initialise
 */
int efx_filter_set_mc_def(struct efx_filter_spec *spec)
{
        EFX_BUG_ON_PARANOID(!(spec->flags &
                              (EFX_FILTER_FLAG_RX | EFX_FILTER_FLAG_TX)));

        if (spec->type != EFX_FILTER_UNSPEC)
                return -EINVAL;

        spec->type = EFX_FILTER_MC_DEF;
        memset(spec->data, 0, sizeof(spec->data)); /* ensure equality */
        return 0;
}

static void efx_filter_reset_rx_def(struct efx_nic *efx, unsigned filter_idx)
{
        struct efx_filter_state *state = efx->filter_state;
        struct efx_filter_table *table = &state->table[EFX_FILTER_TABLE_RX_DEF];
        struct efx_filter_spec *spec = &table->spec[filter_idx];
        enum efx_filter_flags flags = 0;

        /* If there's only one channel then disable RSS for non VF
         * traffic, thereby allowing VFs to use RSS when the PF can't.
         */
        if (efx->n_rx_channels > 1)
                flags |= EFX_FILTER_FLAG_RX_RSS;

        if (efx->rx_scatter)
                flags |= EFX_FILTER_FLAG_RX_SCATTER;

        efx_filter_init_rx(spec, EFX_FILTER_PRI_MANUAL, flags, 0);
        spec->type = EFX_FILTER_UC_DEF + filter_idx;
        table->used_bitmap[0] |= 1 << filter_idx;
}

int efx_filter_get_eth_local(const struct efx_filter_spec *spec,
                             u16 *vid, u8 *addr)
{
        switch (spec->type) {
        case EFX_FILTER_MAC_WILD:
                *vid = EFX_FILTER_VID_UNSPEC;
                break;
        case EFX_FILTER_MAC_FULL:
                *vid = spec->data[0];
                break;
        default:
                return -EINVAL;
        }

        addr[0] = spec->data[2] >> 8;
        addr[1] = spec->data[2];
        addr[2] = spec->data[1] >> 24;
        addr[3] = spec->data[1] >> 16;
        addr[4] = spec->data[1] >> 8;
        addr[5] = spec->data[1];
        return 0;
}

/* Build a filter entry and return its n-tuple key. */
static u32 efx_filter_build(efx_oword_t *filter, struct efx_filter_spec *spec)
{
        u32 data3;

        switch (efx_filter_spec_table_id(spec)) {
        case EFX_FILTER_TABLE_RX_IP: {
                bool is_udp = (spec->type == EFX_FILTER_UDP_FULL ||
                               spec->type == EFX_FILTER_UDP_WILD);
                EFX_POPULATE_OWORD_7(
                        *filter,
                        FRF_BZ_RSS_EN,
                        !!(spec->flags & EFX_FILTER_FLAG_RX_RSS),
                        FRF_BZ_SCATTER_EN,
                        !!(spec->flags & EFX_FILTER_FLAG_RX_SCATTER),
                        FRF_BZ_TCP_UDP, is_udp,
                        FRF_BZ_RXQ_ID, spec->dmaq_id,
                        EFX_DWORD_2, spec->data[2],
                        EFX_DWORD_1, spec->data[1],
                        EFX_DWORD_0, spec->data[0]);
                data3 = is_udp;
                break;
        }

        case EFX_FILTER_TABLE_RX_MAC: {
                bool is_wild = spec->type == EFX_FILTER_MAC_WILD;
                EFX_POPULATE_OWORD_7(
                        *filter,
                        FRF_CZ_RMFT_RSS_EN,
                        !!(spec->flags & EFX_FILTER_FLAG_RX_RSS),
                        FRF_CZ_RMFT_SCATTER_EN,
                        !!(spec->flags & EFX_FILTER_FLAG_RX_SCATTER),
                        FRF_CZ_RMFT_RXQ_ID, spec->dmaq_id,
                        FRF_CZ_RMFT_WILDCARD_MATCH, is_wild,
                        FRF_CZ_RMFT_DEST_MAC_HI, spec->data[2],
                        FRF_CZ_RMFT_DEST_MAC_LO, spec->data[1],
                        FRF_CZ_RMFT_VLAN_ID, spec->data[0]);
                data3 = is_wild;
                break;
        }

        case EFX_FILTER_TABLE_TX_MAC: {
                bool is_wild = spec->type == EFX_FILTER_MAC_WILD;
                EFX_POPULATE_OWORD_5(*filter,
                                     FRF_CZ_TMFT_TXQ_ID, spec->dmaq_id,
                                     FRF_CZ_TMFT_WILDCARD_MATCH, is_wild,
                                     FRF_CZ_TMFT_SRC_MAC_HI, spec->data[2],
                                     FRF_CZ_TMFT_SRC_MAC_LO, spec->data[1],
                                     FRF_CZ_TMFT_VLAN_ID, spec->data[0]);
                data3 = is_wild | spec->dmaq_id << 1;
                break;
        }

        default:
                BUG();
        }

        return spec->data[0] ^ spec->data[1] ^ spec->data[2] ^ data3;
}

static bool efx_filter_equal(const struct efx_filter_spec *left,
                             const struct efx_filter_spec *right)
{
        if (left->type != right->type ||
            memcmp(left->data, right->data, sizeof(left->data)))
                return false;

        if (left->flags & EFX_FILTER_FLAG_TX &&
            left->dmaq_id != right->dmaq_id)
                return false;

        return true;
}

/*
 * Construct/deconstruct external filter IDs.  At least the RX filter
 * IDs must be ordered by matching priority, for RX NFC semantics.
 *
 * Deconstruction needs to be robust against invalid IDs so that
 * efx_filter_remove_id_safe() and efx_filter_get_filter_safe() can
 * accept user-provided IDs.
 */

#define EFX_FILTER_MATCH_PRI_COUNT      5

static const u8 efx_filter_type_match_pri[EFX_FILTER_TYPE_COUNT] = {
        [EFX_FILTER_TCP_FULL]   = 0,
        [EFX_FILTER_UDP_FULL]   = 0,
        [EFX_FILTER_TCP_WILD]   = 1,
        [EFX_FILTER_UDP_WILD]   = 1,
        [EFX_FILTER_MAC_FULL]   = 2,
        [EFX_FILTER_MAC_WILD]   = 3,
        [EFX_FILTER_UC_DEF]     = 4,
        [EFX_FILTER_MC_DEF]     = 4,
};

static const enum efx_filter_table_id efx_filter_range_table[] = {
        EFX_FILTER_TABLE_RX_IP,         /* RX match pri 0 */
        EFX_FILTER_TABLE_RX_IP,
        EFX_FILTER_TABLE_RX_MAC,
        EFX_FILTER_TABLE_RX_MAC,
        EFX_FILTER_TABLE_RX_DEF,        /* RX match pri 4 */
        EFX_FILTER_TABLE_COUNT,         /* TX match pri 0; invalid */
        EFX_FILTER_TABLE_COUNT,         /* invalid */
        EFX_FILTER_TABLE_TX_MAC,
        EFX_FILTER_TABLE_TX_MAC,        /* TX match pri 3 */
};

#define EFX_FILTER_INDEX_WIDTH  13
#define EFX_FILTER_INDEX_MASK   ((1 << EFX_FILTER_INDEX_WIDTH) - 1)

static inline u32
efx_filter_make_id(const struct efx_filter_spec *spec, unsigned int index)
{
        unsigned int range;

        range = efx_filter_type_match_pri[spec->type];
        if (!(spec->flags & EFX_FILTER_FLAG_RX))
                range += EFX_FILTER_MATCH_PRI_COUNT;

        return range << EFX_FILTER_INDEX_WIDTH | index;
}

static inline enum efx_filter_table_id efx_filter_id_table_id(u32 id)
{
        unsigned int range = id >> EFX_FILTER_INDEX_WIDTH;

        if (range < ARRAY_SIZE(efx_filter_range_table))
                return efx_filter_range_table[range];
        else
                return EFX_FILTER_TABLE_COUNT; /* invalid */
}

static inline unsigned int efx_filter_id_index(u32 id)
{
        return id & EFX_FILTER_INDEX_MASK;
}

static inline u8 efx_filter_id_flags(u32 id)
{
        unsigned int range = id >> EFX_FILTER_INDEX_WIDTH;

        if (range < EFX_FILTER_MATCH_PRI_COUNT)
                return EFX_FILTER_FLAG_RX;
        else
                return EFX_FILTER_FLAG_TX;
}

u32 efx_filter_get_rx_id_limit(struct efx_nic *efx)
{
        struct efx_filter_state *state = efx->filter_state;
        unsigned int range = EFX_FILTER_MATCH_PRI_COUNT - 1;
        enum efx_filter_table_id table_id;

        do {
                table_id = efx_filter_range_table[range];
                if (state->table[table_id].size != 0)
                        return range << EFX_FILTER_INDEX_WIDTH |
                                state->table[table_id].size;
        } while (range--);

        return 0;
}

/**
 * efx_filter_insert_filter - add or replace a filter
 * @efx: NIC in which to insert the filter
 * @spec: Specification for the filter
 * @replace_equal: Flag for whether the specified filter may replace an
 *      existing filter with equal priority
 *
 * On success, return the filter ID.
 * On failure, return a negative error code.
 *
 * If an existing filter has equal match values to the new filter
 * spec, then the new filter might replace it, depending on the
 * relative priorities.  If the existing filter has lower priority, or
 * if @replace_equal is set and it has equal priority, then it is
 * replaced.  Otherwise the function fails, returning -%EPERM if
 * the existing filter has higher priority or -%EEXIST if it has
 * equal priority.
 */
s32 efx_filter_insert_filter(struct efx_nic *efx, struct efx_filter_spec *spec,
                             bool replace_equal)
{
        struct efx_filter_state *state = efx->filter_state;
        struct efx_filter_table *table = efx_filter_spec_table(state, spec);
        efx_oword_t filter;
        int rep_index, ins_index;
        unsigned int depth = 0;
        int rc;

        if (!table || table->size == 0)
                return -EINVAL;

        netif_vdbg(efx, hw, efx->net_dev,
                   "%s: type %d search_depth=%d", __func__, spec->type,
                   table->search_depth[spec->type]);

        if (table->id == EFX_FILTER_TABLE_RX_DEF) {
                /* One filter spec per type */
                BUILD_BUG_ON(EFX_FILTER_INDEX_UC_DEF != 0);
                BUILD_BUG_ON(EFX_FILTER_INDEX_MC_DEF !=
                             EFX_FILTER_MC_DEF - EFX_FILTER_UC_DEF);
                rep_index = spec->type - EFX_FILTER_UC_DEF;
                ins_index = rep_index;

                spin_lock_bh(&state->lock);
        } else {
                /* Search concurrently for
                 * (1) a filter to be replaced (rep_index): any filter
                 *     with the same match values, up to the current
                 *     search depth for this type, and
                 * (2) the insertion point (ins_index): (1) or any
                 *     free slot before it or up to the maximum search
                 *     depth for this priority
                 * We fail if we cannot find (2).
                 *
                 * We can stop once either
                 * (a) we find (1), in which case we have definitely
                 *     found (2) as well; or
                 * (b) we have searched exhaustively for (1), and have
                 *     either found (2) or searched exhaustively for it
                 */
                u32 key = efx_filter_build(&filter, spec);
                unsigned int hash = efx_filter_hash(key);
                unsigned int incr = efx_filter_increment(key);
                unsigned int max_rep_depth = table->search_depth[spec->type];
                unsigned int max_ins_depth =
                        spec->priority <= EFX_FILTER_PRI_HINT ?
                        FILTER_CTL_SRCH_HINT_MAX : FILTER_CTL_SRCH_MAX;
                unsigned int i = hash & (table->size - 1);

                ins_index = -1;
                depth = 1;

                spin_lock_bh(&state->lock);

                for (;;) {
                        if (!test_bit(i, table->used_bitmap)) {
                                if (ins_index < 0)
                                        ins_index = i;
                        } else if (efx_filter_equal(spec, &table->spec[i])) {
                                /* Case (a) */
                                if (ins_index < 0)
                                        ins_index = i;
                                rep_index = i;
                                break;
                        }

                        if (depth >= max_rep_depth &&
                            (ins_index >= 0 || depth >= max_ins_depth)) {
                                /* Case (b) */
                                if (ins_index < 0) {
                                        rc = -EBUSY;
                                        goto out;
                                }
                                rep_index = -1;
                                break;
                        }

                        i = (i + incr) & (table->size - 1);
                        ++depth;
                }
        }

        /* If we found a filter to be replaced, check whether we
         * should do so
         */
        if (rep_index >= 0) {
                struct efx_filter_spec *saved_spec = &table->spec[rep_index];

                if (spec->priority == saved_spec->priority && !replace_equal) {
                        rc = -EEXIST;
                        goto out;
                }
                if (spec->priority < saved_spec->priority) {
                        rc = -EPERM;
                        goto out;
                }
        }

        /* Insert the filter */
        if (ins_index != rep_index) {
                __set_bit(ins_index, table->used_bitmap);
                ++table->used;
        }
        table->spec[ins_index] = *spec;

        if (table->id == EFX_FILTER_TABLE_RX_DEF) {
                efx_filter_push_rx_config(efx);
        } else {
                if (table->search_depth[spec->type] < depth) {
                        table->search_depth[spec->type] = depth;
                        if (spec->flags & EFX_FILTER_FLAG_TX)
                                efx_filter_push_tx_limits(efx);
                        else
                                efx_filter_push_rx_config(efx);
                }

                efx_writeo(efx, &filter,
                           table->offset + table->step * ins_index);

                /* If we were able to replace a filter by inserting
                 * at a lower depth, clear the replaced filter
                 */
                if (ins_index != rep_index && rep_index >= 0)
                        efx_filter_table_clear_entry(efx, table, rep_index);
        }

        netif_vdbg(efx, hw, efx->net_dev,
                   "%s: filter type %d index %d rxq %u set",
                   __func__, spec->type, ins_index, spec->dmaq_id);
        rc = efx_filter_make_id(spec, ins_index);

out:
        spin_unlock_bh(&state->lock);
        return rc;
}

static void efx_filter_table_clear_entry(struct efx_nic *efx,
                                         struct efx_filter_table *table,
                                         unsigned int filter_idx)
{
        static efx_oword_t filter;

        if (table->id == EFX_FILTER_TABLE_RX_DEF) {
                /* RX default filters must always exist */
                efx_filter_reset_rx_def(efx, filter_idx);
                efx_filter_push_rx_config(efx);
        } else if (test_bit(filter_idx, table->used_bitmap)) {
                __clear_bit(filter_idx, table->used_bitmap);
                --table->used;
                memset(&table->spec[filter_idx], 0, sizeof(table->spec[0]));

                efx_writeo(efx, &filter,
                           table->offset + table->step * filter_idx);
        }
}

/**
 * efx_filter_remove_id_safe - remove a filter by ID, carefully
 * @efx: NIC from which to remove the filter
 * @priority: Priority of filter, as passed to @efx_filter_insert_filter
 * @filter_id: ID of filter, as returned by @efx_filter_insert_filter
 *
 * This function will range-check @filter_id, so it is safe to call
 * with a value passed from userland.
 */
int efx_filter_remove_id_safe(struct efx_nic *efx,
                              enum efx_filter_priority priority,
                              u32 filter_id)
{
        struct efx_filter_state *state = efx->filter_state;
        enum efx_filter_table_id table_id;
        struct efx_filter_table *table;
        unsigned int filter_idx;
        struct efx_filter_spec *spec;
        u8 filter_flags;
        int rc;

        table_id = efx_filter_id_table_id(filter_id);
        if ((unsigned int)table_id >= EFX_FILTER_TABLE_COUNT)
                return -ENOENT;
        table = &state->table[table_id];

        filter_idx = efx_filter_id_index(filter_id);
        if (filter_idx >= table->size)
                return -ENOENT;
        spec = &table->spec[filter_idx];

        filter_flags = efx_filter_id_flags(filter_id);

        spin_lock_bh(&state->lock);

        if (test_bit(filter_idx, table->used_bitmap) &&
            spec->priority == priority) {
                efx_filter_table_clear_entry(efx, table, filter_idx);
                if (table->used == 0)
                        efx_filter_table_reset_search_depth(table);
                rc = 0;
        } else {
                rc = -ENOENT;
        }

        spin_unlock_bh(&state->lock);

        return rc;
}

/**
 * efx_filter_get_filter_safe - retrieve a filter by ID, carefully
 * @efx: NIC from which to remove the filter
 * @priority: Priority of filter, as passed to @efx_filter_insert_filter
 * @filter_id: ID of filter, as returned by @efx_filter_insert_filter
 * @spec: Buffer in which to store filter specification
 *
 * This function will range-check @filter_id, so it is safe to call
 * with a value passed from userland.
 */
int efx_filter_get_filter_safe(struct efx_nic *efx,
                               enum efx_filter_priority priority,
                               u32 filter_id, struct efx_filter_spec *spec_buf)
{
        struct efx_filter_state *state = efx->filter_state;
        enum efx_filter_table_id table_id;
        struct efx_filter_table *table;
        struct efx_filter_spec *spec;
        unsigned int filter_idx;
        u8 filter_flags;
        int rc;

        table_id = efx_filter_id_table_id(filter_id);
        if ((unsigned int)table_id >= EFX_FILTER_TABLE_COUNT)
                return -ENOENT;
        table = &state->table[table_id];

        filter_idx = efx_filter_id_index(filter_id);
        if (filter_idx >= table->size)
                return -ENOENT;
        spec = &table->spec[filter_idx];

        filter_flags = efx_filter_id_flags(filter_id);

        spin_lock_bh(&state->lock);

        if (test_bit(filter_idx, table->used_bitmap) &&
            spec->priority == priority) {
                *spec_buf = *spec;
                rc = 0;
        } else {
                rc = -ENOENT;
        }

        spin_unlock_bh(&state->lock);

        return rc;
}

static void efx_filter_table_clear(struct efx_nic *efx,
                                   enum efx_filter_table_id table_id,
                                   enum efx_filter_priority priority)
{
        struct efx_filter_state *state = efx->filter_state;
        struct efx_filter_table *table = &state->table[table_id];
        unsigned int filter_idx;

        spin_lock_bh(&state->lock);

        for (filter_idx = 0; filter_idx < table->size; ++filter_idx)
                if (table->spec[filter_idx].priority <= priority)
                        efx_filter_table_clear_entry(efx, table, filter_idx);
        if (table->used == 0)
                efx_filter_table_reset_search_depth(table);

        spin_unlock_bh(&state->lock);
}

/**
 * efx_filter_clear_rx - remove RX filters by priority
 * @efx: NIC from which to remove the filters
 * @priority: Maximum priority to remove
 */
void efx_filter_clear_rx(struct efx_nic *efx, enum efx_filter_priority priority)
{
        efx_filter_table_clear(efx, EFX_FILTER_TABLE_RX_IP, priority);
        efx_filter_table_clear(efx, EFX_FILTER_TABLE_RX_MAC, priority);
}

u32 efx_filter_count_rx_used(struct efx_nic *efx,
                             enum efx_filter_priority priority)
{
        struct efx_filter_state *state = efx->filter_state;
        enum efx_filter_table_id table_id;
        struct efx_filter_table *table;
        unsigned int filter_idx;
        u32 count = 0;

        spin_lock_bh(&state->lock);

        for (table_id = EFX_FILTER_TABLE_RX_IP;
             table_id <= EFX_FILTER_TABLE_RX_DEF;
             table_id++) {
                table = &state->table[table_id];
                for (filter_idx = 0; filter_idx < table->size; filter_idx++) {
                        if (test_bit(filter_idx, table->used_bitmap) &&
                            table->spec[filter_idx].priority == priority)
                                ++count;
                }
        }

        spin_unlock_bh(&state->lock);

        return count;
}

s32 efx_filter_get_rx_ids(struct efx_nic *efx,
                          enum efx_filter_priority priority,
                          u32 *buf, u32 size)
{
        struct efx_filter_state *state = efx->filter_state;
        enum efx_filter_table_id table_id;
        struct efx_filter_table *table;
        unsigned int filter_idx;
        s32 count = 0;

        spin_lock_bh(&state->lock);

        for (table_id = EFX_FILTER_TABLE_RX_IP;
             table_id <= EFX_FILTER_TABLE_RX_DEF;
             table_id++) {
                table = &state->table[table_id];
                for (filter_idx = 0; filter_idx < table->size; filter_idx++) {
                        if (test_bit(filter_idx, table->used_bitmap) &&
                            table->spec[filter_idx].priority == priority) {
                                if (count == size) {
                                        count = -EMSGSIZE;
                                        goto out;
                                }
                                buf[count++] = efx_filter_make_id(
                                        &table->spec[filter_idx], filter_idx);
                        }
                }
        }
out:
        spin_unlock_bh(&state->lock);

        return count;
}

/* Restore filter stater after reset */
void efx_restore_filters(struct efx_nic *efx)
{
        struct efx_filter_state *state = efx->filter_state;
        enum efx_filter_table_id table_id;
        struct efx_filter_table *table;
        efx_oword_t filter;
        unsigned int filter_idx;

        spin_lock_bh(&state->lock);

        for (table_id = 0; table_id < EFX_FILTER_TABLE_COUNT; table_id++) {
                table = &state->table[table_id];

                /* Check whether this is a regular register table */
                if (table->step == 0)
                        continue;

                for (filter_idx = 0; filter_idx < table->size; filter_idx++) {
                        if (!test_bit(filter_idx, table->used_bitmap))
                                continue;
                        efx_filter_build(&filter, &table->spec[filter_idx]);
                        efx_writeo(efx, &filter,
                                   table->offset + table->step * filter_idx);
                }
        }

        efx_filter_push_rx_config(efx);
        efx_filter_push_tx_limits(efx);

        spin_unlock_bh(&state->lock);
}

int efx_probe_filters(struct efx_nic *efx)
{
        struct efx_filter_state *state;
        struct efx_filter_table *table;
        unsigned table_id;

        state = kzalloc(sizeof(*efx->filter_state), GFP_KERNEL);
        if (!state)
                return -ENOMEM;
        efx->filter_state = state;

        spin_lock_init(&state->lock);

        if (efx_nic_rev(efx) >= EFX_REV_FALCON_B0) {
#ifdef CONFIG_RFS_ACCEL
                state->rps_flow_id = kcalloc(FR_BZ_RX_FILTER_TBL0_ROWS,
                                             sizeof(*state->rps_flow_id),
                                             GFP_KERNEL);
                if (!state->rps_flow_id)
                        goto fail;
#endif
                table = &state->table[EFX_FILTER_TABLE_RX_IP];
                table->id = EFX_FILTER_TABLE_RX_IP;
                table->offset = FR_BZ_RX_FILTER_TBL0;
                table->size = FR_BZ_RX_FILTER_TBL0_ROWS;
                table->step = FR_BZ_RX_FILTER_TBL0_STEP;
        }

        if (efx_nic_rev(efx) >= EFX_REV_SIENA_A0) {
                table = &state->table[EFX_FILTER_TABLE_RX_MAC];
                table->id = EFX_FILTER_TABLE_RX_MAC;
                table->offset = FR_CZ_RX_MAC_FILTER_TBL0;
                table->size = FR_CZ_RX_MAC_FILTER_TBL0_ROWS;
                table->step = FR_CZ_RX_MAC_FILTER_TBL0_STEP;

                table = &state->table[EFX_FILTER_TABLE_RX_DEF];
                table->id = EFX_FILTER_TABLE_RX_DEF;
                table->size = EFX_FILTER_SIZE_RX_DEF;

                table = &state->table[EFX_FILTER_TABLE_TX_MAC];
                table->id = EFX_FILTER_TABLE_TX_MAC;
                table->offset = FR_CZ_TX_MAC_FILTER_TBL0;
                table->size = FR_CZ_TX_MAC_FILTER_TBL0_ROWS;
                table->step = FR_CZ_TX_MAC_FILTER_TBL0_STEP;
        }

        for (table_id = 0; table_id < EFX_FILTER_TABLE_COUNT; table_id++) {
                table = &state->table[table_id];
                if (table->size == 0)
                        continue;
                table->used_bitmap = kcalloc(BITS_TO_LONGS(table->size),
                                             sizeof(unsigned long),
                                             GFP_KERNEL);
                if (!table->used_bitmap)
                        goto fail;
                table->spec = vzalloc(table->size * sizeof(*table->spec));
                if (!table->spec)
                        goto fail;
        }

        if (state->table[EFX_FILTER_TABLE_RX_DEF].size) {
                /* RX default filters must always exist */
                unsigned i;
                for (i = 0; i < EFX_FILTER_SIZE_RX_DEF; i++)
                        efx_filter_reset_rx_def(efx, i);
        }

        efx_filter_push_rx_config(efx);

        return 0;

fail:
        efx_remove_filters(efx);
        return -ENOMEM;
}

void efx_remove_filters(struct efx_nic *efx)
{
        struct efx_filter_state *state = efx->filter_state;
        enum efx_filter_table_id table_id;

        for (table_id = 0; table_id < EFX_FILTER_TABLE_COUNT; table_id++) {
                kfree(state->table[table_id].used_bitmap);
                vfree(state->table[table_id].spec);
        }
#ifdef CONFIG_RFS_ACCEL
        kfree(state->rps_flow_id);
#endif
        kfree(state);
}

/* Update scatter enable flags for filters pointing to our own RX queues */
void efx_filter_update_rx_scatter(struct efx_nic *efx)
{
        struct efx_filter_state *state = efx->filter_state;
        enum efx_filter_table_id table_id;
        struct efx_filter_table *table;
        efx_oword_t filter;
        unsigned int filter_idx;

        spin_lock_bh(&state->lock);

        for (table_id = EFX_FILTER_TABLE_RX_IP;
             table_id <= EFX_FILTER_TABLE_RX_DEF;
             table_id++) {
                table = &state->table[table_id];

                for (filter_idx = 0; filter_idx < table->size; filter_idx++) {
                        if (!test_bit(filter_idx, table->used_bitmap) ||
                            table->spec[filter_idx].dmaq_id >=
                            efx->n_rx_channels)
                                continue;

                        if (efx->rx_scatter)
                                table->spec[filter_idx].flags |=
                                        EFX_FILTER_FLAG_RX_SCATTER;
                        else
                                table->spec[filter_idx].flags &=
                                        ~EFX_FILTER_FLAG_RX_SCATTER;

                        if (table_id == EFX_FILTER_TABLE_RX_DEF)
                                /* Pushed by efx_filter_push_rx_config() */
                                continue;

                        efx_filter_build(&filter, &table->spec[filter_idx]);
                        efx_writeo(efx, &filter,
                                   table->offset + table->step * filter_idx);
                }
        }

        efx_filter_push_rx_config(efx);

        spin_unlock_bh(&state->lock);
}

#ifdef CONFIG_RFS_ACCEL

int efx_filter_rfs(struct net_device *net_dev, const struct sk_buff *skb,
                   u16 rxq_index, u32 flow_id)
{
        struct efx_nic *efx = netdev_priv(net_dev);
        struct efx_channel *channel;
        struct efx_filter_state *state = efx->filter_state;
        struct efx_filter_spec spec;
        const struct iphdr *ip;
        const __be16 *ports;
        int nhoff;
        int rc;

        nhoff = skb_network_offset(skb);

        if (skb->protocol == htons(ETH_P_8021Q)) {
                EFX_BUG_ON_PARANOID(skb_headlen(skb) <
                                    nhoff + sizeof(struct vlan_hdr));
                if (((const struct vlan_hdr *)skb->data + nhoff)->
                    h_vlan_encapsulated_proto != htons(ETH_P_IP))
                        return -EPROTONOSUPPORT;

                /* This is IP over 802.1q VLAN.  We can't filter on the
                 * IP 5-tuple and the vlan together, so just strip the
                 * vlan header and filter on the IP part.
                 */
                nhoff += sizeof(struct vlan_hdr);
        } else if (skb->protocol != htons(ETH_P_IP)) {
                return -EPROTONOSUPPORT;
        }

        /* RFS must validate the IP header length before calling us */
        EFX_BUG_ON_PARANOID(skb_headlen(skb) < nhoff + sizeof(*ip));
        ip = (const struct iphdr *)(skb->data + nhoff);
        if (ip_is_fragment(ip))
                return -EPROTONOSUPPORT;
        EFX_BUG_ON_PARANOID(skb_headlen(skb) < nhoff + 4 * ip->ihl + 4);
        ports = (const __be16 *)(skb->data + nhoff + 4 * ip->ihl);

        efx_filter_init_rx(&spec, EFX_FILTER_PRI_HINT,
                           efx->rx_scatter ? EFX_FILTER_FLAG_RX_SCATTER : 0,
                           rxq_index);
        rc = efx_filter_set_ipv4_full(&spec, ip->protocol,
                                      ip->daddr, ports[1], ip->saddr, ports[0]);
        if (rc)
                return rc;

        rc = efx_filter_insert_filter(efx, &spec, true);
        if (rc < 0)
                return rc;

        /* Remember this so we can check whether to expire the filter later */
        state->rps_flow_id[rc] = flow_id;
        channel = efx_get_channel(efx, skb_get_rx_queue(skb));
        ++channel->rfs_filters_added;

        netif_info(efx, rx_status, efx->net_dev,
                   "steering %s %pI4:%u:%pI4:%u to queue %u [flow %u filter %d]\n",
                   (ip->protocol == IPPROTO_TCP) ? "TCP" : "UDP",
                   &ip->saddr, ntohs(ports[0]), &ip->daddr, ntohs(ports[1]),
                   rxq_index, flow_id, rc);

        return rc;
}

bool __efx_filter_rfs_expire(struct efx_nic *efx, unsigned quota)
{
        struct efx_filter_state *state = efx->filter_state;
        struct efx_filter_table *table = &state->table[EFX_FILTER_TABLE_RX_IP];
        unsigned mask = table->size - 1;
        unsigned index;
        unsigned stop;

        if (!spin_trylock_bh(&state->lock))
                return false;

        index = state->rps_expire_index;
        stop = (index + quota) & mask;

        while (index != stop) {
                if (test_bit(index, table->used_bitmap) &&
                    table->spec[index].priority == EFX_FILTER_PRI_HINT &&
                    rps_may_expire_flow(efx->net_dev,
                                        table->spec[index].dmaq_id,
                                        state->rps_flow_id[index], index)) {
                        netif_info(efx, rx_status, efx->net_dev,
                                   "expiring filter %d [flow %u]\n",
                                   index, state->rps_flow_id[index]);
                        efx_filter_table_clear_entry(efx, table, index);
                }
                index = (index + 1) & mask;
        }

        state->rps_expire_index = stop;
        if (table->used == 0)
                efx_filter_table_reset_search_depth(table);

        spin_unlock_bh(&state->lock);
        return true;
}

#endif /* CONFIG_RFS_ACCEL */