/*
 * Copyright (c) 2009 Atheros Communications Inc.
 * Copyright (c) 2010 Bruno Randolf <br1@einfach.org>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <asm/unaligned.h>
#include <linux/export.h>
#include <net/mac80211.h>

#include "ath.h"
#include "reg.h"

#define REG_READ (common->ops->read)
#define REG_WRITE(_ah, _reg, _val) (common->ops->write)(_ah, _val, _reg)
#define ENABLE_REGWRITE_BUFFER(_ah) \
    if (common->ops->enable_write_buffer) common->ops->enable_write_buffer((_ah));

#define REGWRITE_BUFFER_FLUSH(_ah) \
    if (common->ops->write_flush) common->ops->write_flush((_ah));

#define IEEE80211_WEP_NKID 4 /* number of key ids */

/************************/
/* Key Cache Management */
/************************/

bool ath_hw_keyreset(struct ath_common* common, uint16_t entry) {
    uint32_t keyType;
    void* ah = common->ah;

    if (entry >= common->keymax) {
        ath_err(common, "keyreset: keycache entry %u out of range\n", entry);
        return false;
    }

    keyType = REG_READ(ah, AR_KEYTABLE_TYPE(entry));

    ENABLE_REGWRITE_BUFFER(ah);

    REG_WRITE(ah, AR_KEYTABLE_KEY0(entry), 0);
    REG_WRITE(ah, AR_KEYTABLE_KEY1(entry), 0);
    REG_WRITE(ah, AR_KEYTABLE_KEY2(entry), 0);
    REG_WRITE(ah, AR_KEYTABLE_KEY3(entry), 0);
    REG_WRITE(ah, AR_KEYTABLE_KEY4(entry), 0);
    REG_WRITE(ah, AR_KEYTABLE_TYPE(entry), AR_KEYTABLE_TYPE_CLR);
    REG_WRITE(ah, AR_KEYTABLE_MAC0(entry), 0);
    REG_WRITE(ah, AR_KEYTABLE_MAC1(entry), 0);

    if (keyType == AR_KEYTABLE_TYPE_TKIP) {
        uint16_t micentry = entry + 64;

        REG_WRITE(ah, AR_KEYTABLE_KEY0(micentry), 0);
        REG_WRITE(ah, AR_KEYTABLE_KEY1(micentry), 0);
        REG_WRITE(ah, AR_KEYTABLE_KEY2(micentry), 0);
        REG_WRITE(ah, AR_KEYTABLE_KEY3(micentry), 0);
        if (common->crypt_caps & ATH_CRYPT_CAP_MIC_COMBINED) {
            REG_WRITE(ah, AR_KEYTABLE_KEY4(micentry), 0);
            REG_WRITE(ah, AR_KEYTABLE_TYPE(micentry), AR_KEYTABLE_TYPE_CLR);
        }
    }

    REGWRITE_BUFFER_FLUSH(ah);

    return true;
}
EXPORT_SYMBOL(ath_hw_keyreset);

static bool ath_hw_keysetmac(struct ath_common* common, uint16_t entry, const uint8_t* mac) {
    uint32_t macHi, macLo;
    uint32_t unicast_flag = AR_KEYTABLE_VALID;
    void* ah = common->ah;

    if (entry >= common->keymax) {
        ath_err(common, "keysetmac: keycache entry %u out of range\n", entry);
        return false;
    }

    if (mac != NULL) {
        /*
         * AR_KEYTABLE_VALID indicates that the address is a unicast
         * address, which must match the transmitter address for
         * decrypting frames.
         * Not setting this bit allows the hardware to use the key
         * for multicast frame decryption.
         */
        if (mac[0] & 0x01) { unicast_flag = 0; }

        macLo = get_unaligned_le32(mac);
        macHi = get_unaligned_le16(mac + 4);
        macLo >>= 1;
        macLo |= (macHi & 1) << 31;
        macHi >>= 1;
    } else {
        macLo = macHi = 0;
    }
    ENABLE_REGWRITE_BUFFER(ah);

    REG_WRITE(ah, AR_KEYTABLE_MAC0(entry), macLo);
    REG_WRITE(ah, AR_KEYTABLE_MAC1(entry), macHi | unicast_flag);

    REGWRITE_BUFFER_FLUSH(ah);

    return true;
}

static bool ath_hw_set_keycache_entry(struct ath_common* common, uint16_t entry,
                                      const struct ath_keyval* k, const uint8_t* mac) {
    void* ah = common->ah;
    uint32_t key0, key1, key2, key3, key4;
    uint32_t keyType;

    if (entry >= common->keymax) {
        ath_err(common, "set-entry: keycache entry %u out of range\n", entry);
        return false;
    }

    switch (k->kv_type) {
    case ATH_CIPHER_AES_OCB:
        keyType = AR_KEYTABLE_TYPE_AES;
        break;
    case ATH_CIPHER_AES_CCM:
        if (!(common->crypt_caps & ATH_CRYPT_CAP_CIPHER_AESCCM)) {
            ath_dbg(common, ANY, "AES-CCM not supported by this mac rev\n");
            return false;
        }
        keyType = AR_KEYTABLE_TYPE_CCM;
        break;
    case ATH_CIPHER_TKIP:
        keyType = AR_KEYTABLE_TYPE_TKIP;
        if (entry + 64 >= common->keymax) {
            ath_dbg(common, ANY, "entry %u inappropriate for TKIP\n", entry);
            return false;
        }
        break;
    case ATH_CIPHER_WEP:
        if (k->kv_len < WLAN_KEY_LEN_WEP40) {
            ath_dbg(common, ANY, "WEP key length %u too small\n", k->kv_len);
            return false;
        }
        if (k->kv_len <= WLAN_KEY_LEN_WEP40) {
            keyType = AR_KEYTABLE_TYPE_40;
        } else if (k->kv_len <= WLAN_KEY_LEN_WEP104) {
            keyType = AR_KEYTABLE_TYPE_104;
        } else {
            keyType = AR_KEYTABLE_TYPE_128;
        }
        break;
    case ATH_CIPHER_CLR:
        keyType = AR_KEYTABLE_TYPE_CLR;
        break;
    default:
        ath_err(common, "cipher %u not supported\n", k->kv_type);
        return false;
    }

    key0 = get_unaligned_le32(k->kv_val + 0);
    key1 = get_unaligned_le16(k->kv_val + 4);
    key2 = get_unaligned_le32(k->kv_val + 6);
    key3 = get_unaligned_le16(k->kv_val + 10);
    key4 = get_unaligned_le32(k->kv_val + 12);
    if (k->kv_len <= WLAN_KEY_LEN_WEP104) { key4 &= 0xff; }

    /*
     * Note: Key cache registers access special memory area that requires
     * two 32-bit writes to actually update the values in the internal
     * memory. Consequently, the exact order and pairs used here must be
     * maintained.
     */

    if (keyType == AR_KEYTABLE_TYPE_TKIP) {
        uint16_t micentry = entry + 64;

        /*
         * Write inverted key[47:0] first to avoid Michael MIC errors
         * on frames that could be sent or received at the same time.
         * The correct key will be written in the end once everything
         * else is ready.
         */
        REG_WRITE(ah, AR_KEYTABLE_KEY0(entry), ~key0);
        REG_WRITE(ah, AR_KEYTABLE_KEY1(entry), ~key1);

        /* Write key[95:48] */
        REG_WRITE(ah, AR_KEYTABLE_KEY2(entry), key2);
        REG_WRITE(ah, AR_KEYTABLE_KEY3(entry), key3);

        /* Write key[127:96] and key type */
        REG_WRITE(ah, AR_KEYTABLE_KEY4(entry), key4);
        REG_WRITE(ah, AR_KEYTABLE_TYPE(entry), keyType);

        /* Write MAC address for the entry */
        (void)ath_hw_keysetmac(common, entry, mac);

        if (common->crypt_caps & ATH_CRYPT_CAP_MIC_COMBINED) {
            /*
             * TKIP uses two key cache entries:
             * Michael MIC TX/RX keys in the same key cache entry
             * (idx = main index + 64):
             * key0 [31:0] = RX key [31:0]
             * key1 [15:0] = TX key [31:16]
             * key1 [31:16] = reserved
             * key2 [31:0] = RX key [63:32]
             * key3 [15:0] = TX key [15:0]
             * key3 [31:16] = reserved
             * key4 [31:0] = TX key [63:32]
             */
            uint32_t mic0, mic1, mic2, mic3, mic4;

            mic0 = get_unaligned_le32(k->kv_mic + 0);
            mic2 = get_unaligned_le32(k->kv_mic + 4);
            mic1 = get_unaligned_le16(k->kv_txmic + 2) & 0xffff;
            mic3 = get_unaligned_le16(k->kv_txmic + 0) & 0xffff;
            mic4 = get_unaligned_le32(k->kv_txmic + 4);

            ENABLE_REGWRITE_BUFFER(ah);

            /* Write RX[31:0] and TX[31:16] */
            REG_WRITE(ah, AR_KEYTABLE_KEY0(micentry), mic0);
            REG_WRITE(ah, AR_KEYTABLE_KEY1(micentry), mic1);

            /* Write RX[63:32] and TX[15:0] */
            REG_WRITE(ah, AR_KEYTABLE_KEY2(micentry), mic2);
            REG_WRITE(ah, AR_KEYTABLE_KEY3(micentry), mic3);

            /* Write TX[63:32] and keyType(reserved) */
            REG_WRITE(ah, AR_KEYTABLE_KEY4(micentry), mic4);
            REG_WRITE(ah, AR_KEYTABLE_TYPE(micentry), AR_KEYTABLE_TYPE_CLR);

            REGWRITE_BUFFER_FLUSH(ah);

        } else {
            /*
             * TKIP uses four key cache entries (two for group
             * keys):
             * Michael MIC TX/RX keys are in different key cache
             * entries (idx = main index + 64 for TX and
             * main index + 32 + 96 for RX):
             * key0 [31:0] = TX/RX MIC key [31:0]
             * key1 [31:0] = reserved
             * key2 [31:0] = TX/RX MIC key [63:32]
             * key3 [31:0] = reserved
             * key4 [31:0] = reserved
             *
             * Upper layer code will call this function separately
             * for TX and RX keys when these registers offsets are
             * used.
             */
            uint32_t mic0, mic2;

            mic0 = get_unaligned_le32(k->kv_mic + 0);
            mic2 = get_unaligned_le32(k->kv_mic + 4);

            ENABLE_REGWRITE_BUFFER(ah);

            /* Write MIC key[31:0] */
            REG_WRITE(ah, AR_KEYTABLE_KEY0(micentry), mic0);
            REG_WRITE(ah, AR_KEYTABLE_KEY1(micentry), 0);

            /* Write MIC key[63:32] */
            REG_WRITE(ah, AR_KEYTABLE_KEY2(micentry), mic2);
            REG_WRITE(ah, AR_KEYTABLE_KEY3(micentry), 0);

            /* Write TX[63:32] and keyType(reserved) */
            REG_WRITE(ah, AR_KEYTABLE_KEY4(micentry), 0);
            REG_WRITE(ah, AR_KEYTABLE_TYPE(micentry), AR_KEYTABLE_TYPE_CLR);

            REGWRITE_BUFFER_FLUSH(ah);
        }

        ENABLE_REGWRITE_BUFFER(ah);

        /* MAC address registers are reserved for the MIC entry */
        REG_WRITE(ah, AR_KEYTABLE_MAC0(micentry), 0);
        REG_WRITE(ah, AR_KEYTABLE_MAC1(micentry), 0);

        /*
         * Write the correct (un-inverted) key[47:0] last to enable
         * TKIP now that all other registers are set with correct
         * values.
         */
        REG_WRITE(ah, AR_KEYTABLE_KEY0(entry), key0);
        REG_WRITE(ah, AR_KEYTABLE_KEY1(entry), key1);

        REGWRITE_BUFFER_FLUSH(ah);
    } else {
        ENABLE_REGWRITE_BUFFER(ah);

        /* Write key[47:0] */
        REG_WRITE(ah, AR_KEYTABLE_KEY0(entry), key0);
        REG_WRITE(ah, AR_KEYTABLE_KEY1(entry), key1);

        /* Write key[95:48] */
        REG_WRITE(ah, AR_KEYTABLE_KEY2(entry), key2);
        REG_WRITE(ah, AR_KEYTABLE_KEY3(entry), key3);

        /* Write key[127:96] and key type */
        REG_WRITE(ah, AR_KEYTABLE_KEY4(entry), key4);
        REG_WRITE(ah, AR_KEYTABLE_TYPE(entry), keyType);

        REGWRITE_BUFFER_FLUSH(ah);

        /* Write MAC address for the entry */
        (void)ath_hw_keysetmac(common, entry, mac);
    }

    return true;
}

static int ath_setkey_tkip(struct ath_common* common, uint16_t keyix, const uint8_t* key,
                           struct ath_keyval* hk, const uint8_t* addr, bool authenticator) {
    const uint8_t* key_rxmic;
    const uint8_t* key_txmic;

    key_txmic = key + NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY;
    key_rxmic = key + NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY;

    if (addr == NULL) {
        /*
         * Group key installation - only two key cache entries are used
         * regardless of splitmic capability since group key is only
         * used either for TX or RX.
         */
        if (authenticator) {
            memcpy(hk->kv_mic, key_txmic, sizeof(hk->kv_mic));
            memcpy(hk->kv_txmic, key_txmic, sizeof(hk->kv_mic));
        } else {
            memcpy(hk->kv_mic, key_rxmic, sizeof(hk->kv_mic));
            memcpy(hk->kv_txmic, key_rxmic, sizeof(hk->kv_mic));
        }
        return ath_hw_set_keycache_entry(common, keyix, hk, addr);
    }
    if (common->crypt_caps & ATH_CRYPT_CAP_MIC_COMBINED) {
        /* TX and RX keys share the same key cache entry. */
        memcpy(hk->kv_mic, key_rxmic, sizeof(hk->kv_mic));
        memcpy(hk->kv_txmic, key_txmic, sizeof(hk->kv_txmic));
        return ath_hw_set_keycache_entry(common, keyix, hk, addr);
    }

    /* Separate key cache entries for TX and RX */

    /* TX key goes at first index, RX key at +32. */
    memcpy(hk->kv_mic, key_txmic, sizeof(hk->kv_mic));
    if (!ath_hw_set_keycache_entry(common, keyix, hk, NULL)) {
        /* TX MIC entry failed. No need to proceed further */
        ath_err(common, "Setting TX MIC Key Failed\n");
        return 0;
    }

    memcpy(hk->kv_mic, key_rxmic, sizeof(hk->kv_mic));
    /* XXX delete tx key on failure? */
    return ath_hw_set_keycache_entry(common, keyix + 32, hk, addr);
}

static int ath_reserve_key_cache_slot_tkip(struct ath_common* common) {
    int i;

    for (i = IEEE80211_WEP_NKID; i < common->keymax / 2; i++) {
        if (test_bit(i, common->keymap) || test_bit(i + 64, common->keymap)) {
            continue; /* At least one part of TKIP key allocated */
        }
        if (!(common->crypt_caps & ATH_CRYPT_CAP_MIC_COMBINED) &&
            (test_bit(i + 32, common->keymap) || test_bit(i + 64 + 32, common->keymap))) {
            continue; /* At least one part of TKIP key allocated */
        }

        /* Found a free slot for a TKIP key */
        return i;
    }
    return -1;
}

static int ath_reserve_key_cache_slot(struct ath_common* common, uint32_t cipher) {
    int i;

    if (cipher == WLAN_CIPHER_SUITE_TKIP) { return ath_reserve_key_cache_slot_tkip(common); }

    /* First, try to find slots that would not be available for TKIP. */
    if (!(common->crypt_caps & ATH_CRYPT_CAP_MIC_COMBINED)) {
        for (i = IEEE80211_WEP_NKID; i < common->keymax / 4; i++) {
            if (!test_bit(i, common->keymap) &&
                (test_bit(i + 32, common->keymap) || test_bit(i + 64, common->keymap) ||
                 test_bit(i + 64 + 32, common->keymap))) {
                return i;
            }
            if (!test_bit(i + 32, common->keymap) &&
                (test_bit(i, common->keymap) || test_bit(i + 64, common->keymap) ||
                 test_bit(i + 64 + 32, common->keymap))) {
                return i + 32;
            }
            if (!test_bit(i + 64, common->keymap) &&
                (test_bit(i, common->keymap) || test_bit(i + 32, common->keymap) ||
                 test_bit(i + 64 + 32, common->keymap))) {
                return i + 64;
            }
            if (!test_bit(i + 64 + 32, common->keymap) &&
                (test_bit(i, common->keymap) || test_bit(i + 32, common->keymap) ||
                 test_bit(i + 64, common->keymap))) {
                return i + 64 + 32;
            }
        }
    } else {
        for (i = IEEE80211_WEP_NKID; i < common->keymax / 2; i++) {
            if (!test_bit(i, common->keymap) && test_bit(i + 64, common->keymap)) { return i; }
            if (test_bit(i, common->keymap) && !test_bit(i + 64, common->keymap)) { return i + 64; }
        }
    }

    /* No partially used TKIP slots, pick any available slot */
    for (i = IEEE80211_WEP_NKID; i < common->keymax; i++) {
        /* Do not allow slots that could be needed for TKIP group keys
         * to be used. This limitation could be removed if we know that
         * TKIP will not be used. */
        if (i >= 64 && i < 64 + IEEE80211_WEP_NKID) { continue; }
        if (!(common->crypt_caps & ATH_CRYPT_CAP_MIC_COMBINED)) {
            if (i >= 32 && i < 32 + IEEE80211_WEP_NKID) { continue; }
            if (i >= 64 + 32 && i < 64 + 32 + IEEE80211_WEP_NKID) { continue; }
        }

        if (!test_bit(i, common->keymap)) { return i; /* Found a free slot for a key */ }
    }

    /* No free slot found */
    return -1;
}

/*
 * Configure encryption in the HW.
 */
int ath_key_config(struct ath_common* common, struct ieee80211_vif* vif, struct ieee80211_sta* sta,
                   struct ieee80211_key_conf* key) {
    struct ath_keyval hk;
    const uint8_t* mac = NULL;
    uint8_t gmac[ETH_ALEN];
    int ret = 0;
    int idx;

    memset(&hk, 0, sizeof(hk));

    switch (key->cipher) {
    case 0:
        hk.kv_type = ATH_CIPHER_CLR;
        break;
    case WLAN_CIPHER_SUITE_WEP40:
    case WLAN_CIPHER_SUITE_WEP104:
        hk.kv_type = ATH_CIPHER_WEP;
        break;
    case WLAN_CIPHER_SUITE_TKIP:
        hk.kv_type = ATH_CIPHER_TKIP;
        break;
    case WLAN_CIPHER_SUITE_CCMP:
        hk.kv_type = ATH_CIPHER_AES_CCM;
        break;
    default:
        return -EOPNOTSUPP;
    }

    hk.kv_len = key->keylen;
    if (key->keylen) { memcpy(hk.kv_val, key->key, key->keylen); }

    if (!(key->flags & IEEE80211_KEY_FLAG_PAIRWISE)) {
        switch (vif->type) {
        case NL80211_IFTYPE_AP:
            memcpy(gmac, vif->addr, ETH_ALEN);
            gmac[0] |= 0x01;
            mac = gmac;
            idx = ath_reserve_key_cache_slot(common, key->cipher);
            break;
        case NL80211_IFTYPE_ADHOC:
            if (!sta) {
                idx = key->keyidx;
                break;
            }
            memcpy(gmac, sta->addr, ETH_ALEN);
            gmac[0] |= 0x01;
            mac = gmac;
            idx = ath_reserve_key_cache_slot(common, key->cipher);
            break;
        default:
            idx = key->keyidx;
            break;
        }
    } else if (key->keyidx) {
        if (WARN_ON(!sta)) { return -EOPNOTSUPP; }
        mac = sta->addr;

        if (vif->type != NL80211_IFTYPE_AP) {
            /* Only keyidx 0 should be used with unicast key, but
             * allow this for client mode for now. */
            idx = key->keyidx;
        } else {
            return -EIO;
        }
    } else {
        if (WARN_ON(!sta)) { return -EOPNOTSUPP; }
        mac = sta->addr;

        idx = ath_reserve_key_cache_slot(common, key->cipher);
    }

    if (idx < 0) { return -ENOSPC; /* no free key cache entries */ }

    if (key->cipher == WLAN_CIPHER_SUITE_TKIP)
        ret = ath_setkey_tkip(common, idx, key->key, &hk, mac, vif->type == NL80211_IFTYPE_AP);
    else {
        ret = ath_hw_set_keycache_entry(common, idx, &hk, mac);
    }

    if (!ret) { return -EIO; }

    set_bit(idx, common->keymap);
    if (key->cipher == WLAN_CIPHER_SUITE_CCMP) { set_bit(idx, common->ccmp_keymap); }

    if (key->cipher == WLAN_CIPHER_SUITE_TKIP) {
        set_bit(idx + 64, common->keymap);
        set_bit(idx, common->tkip_keymap);
        set_bit(idx + 64, common->tkip_keymap);
        if (!(common->crypt_caps & ATH_CRYPT_CAP_MIC_COMBINED)) {
            set_bit(idx + 32, common->keymap);
            set_bit(idx + 64 + 32, common->keymap);
            set_bit(idx + 32, common->tkip_keymap);
            set_bit(idx + 64 + 32, common->tkip_keymap);
        }
    }

    return idx;
}
EXPORT_SYMBOL(ath_key_config);

/*
 * Delete Key.
 */
void ath_key_delete(struct ath_common* common, struct ieee80211_key_conf* key) {
    ath_hw_keyreset(common, key->hw_key_idx);
    if (key->hw_key_idx < IEEE80211_WEP_NKID) { return; }

    clear_bit(key->hw_key_idx, common->keymap);
    clear_bit(key->hw_key_idx, common->ccmp_keymap);
    if (key->cipher != WLAN_CIPHER_SUITE_TKIP) { return; }

    clear_bit(key->hw_key_idx + 64, common->keymap);

    clear_bit(key->hw_key_idx, common->tkip_keymap);
    clear_bit(key->hw_key_idx + 64, common->tkip_keymap);

    if (!(common->crypt_caps & ATH_CRYPT_CAP_MIC_COMBINED)) {
        ath_hw_keyreset(common, key->hw_key_idx + 32);
        clear_bit(key->hw_key_idx + 32, common->keymap);
        clear_bit(key->hw_key_idx + 64 + 32, common->keymap);

        clear_bit(key->hw_key_idx + 32, common->tkip_keymap);
        clear_bit(key->hw_key_idx + 64 + 32, common->tkip_keymap);
    }
}
EXPORT_SYMBOL(ath_key_delete);