/*
 * Copyright (c) 2008-2009 Atheros Communications Inc.
 *
 * 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 <linux/kernel.h>
#include <linux/slab.h>
#include <net/cfg80211.h>
#include <net/mac80211.h>
#include "regd.h"
#include "regd_common.h"

/*
 * This is a set of common rules used by our world regulatory domains.
 * We have 12 world regulatory domains. To save space we consolidate
 * the regulatory domains in 5 structures by frequency and change
 * the flags on our reg_notifier() on a case by case basis.
 */

/* Only these channels all allow active scan on all world regulatory domains */
#define ATH9K_2GHZ_CH01_11      REG_RULE(2412-10, 2462+10, 40, 0, 20, 0)

/* We enable active scan on these a case by case basis by regulatory domain */
#define ATH9K_2GHZ_CH12_13      REG_RULE(2467-10, 2472+10, 40, 0, 20,\
                                        NL80211_RRF_PASSIVE_SCAN)
#define ATH9K_2GHZ_CH14         REG_RULE(2484-10, 2484+10, 40, 0, 20,\
                                NL80211_RRF_PASSIVE_SCAN | NL80211_RRF_NO_OFDM)

/* We allow IBSS on these on a case by case basis by regulatory domain */
#define ATH9K_5GHZ_5150_5350    REG_RULE(5150-10, 5350+10, 40, 0, 30,\
                                NL80211_RRF_PASSIVE_SCAN | NL80211_RRF_NO_IBSS)
#define ATH9K_5GHZ_5470_5850    REG_RULE(5470-10, 5850+10, 40, 0, 30,\
                                NL80211_RRF_PASSIVE_SCAN | NL80211_RRF_NO_IBSS)
#define ATH9K_5GHZ_5725_5850    REG_RULE(5725-10, 5850+10, 40, 0, 30,\
                                NL80211_RRF_PASSIVE_SCAN | NL80211_RRF_NO_IBSS)

#define ATH9K_2GHZ_ALL          ATH9K_2GHZ_CH01_11, \
                                ATH9K_2GHZ_CH12_13, \
                                ATH9K_2GHZ_CH14

#define ATH9K_5GHZ_ALL          ATH9K_5GHZ_5150_5350, \
                                ATH9K_5GHZ_5470_5850
/* This one skips what we call "mid band" */
#define ATH9K_5GHZ_NO_MIDBAND   ATH9K_5GHZ_5150_5350, \
                                ATH9K_5GHZ_5725_5850

/* Can be used for:
 * 0x60, 0x61, 0x62 */
static const struct ieee80211_regdomain ath_world_regdom_60_61_62 = {
        .n_reg_rules = 5,
        .alpha2 =  "99",
        .reg_rules = {
                ATH9K_2GHZ_ALL,
                ATH9K_5GHZ_ALL,
        }
};

/* Can be used by 0x63 and 0x65 */
static const struct ieee80211_regdomain ath_world_regdom_63_65 = {
        .n_reg_rules = 4,
        .alpha2 =  "99",
        .reg_rules = {
                ATH9K_2GHZ_CH01_11,
                ATH9K_2GHZ_CH12_13,
                ATH9K_5GHZ_NO_MIDBAND,
        }
};

/* Can be used by 0x64 only */
static const struct ieee80211_regdomain ath_world_regdom_64 = {
        .n_reg_rules = 3,
        .alpha2 =  "99",
        .reg_rules = {
                ATH9K_2GHZ_CH01_11,
                ATH9K_5GHZ_NO_MIDBAND,
        }
};

/* Can be used by 0x66 and 0x69 */
static const struct ieee80211_regdomain ath_world_regdom_66_69 = {
        .n_reg_rules = 3,
        .alpha2 =  "99",
        .reg_rules = {
                ATH9K_2GHZ_CH01_11,
                ATH9K_5GHZ_ALL,
        }
};

/* Can be used by 0x67, 0x6A and 0x68 */
static const struct ieee80211_regdomain ath_world_regdom_67_68_6A = {
        .n_reg_rules = 4,
        .alpha2 =  "99",
        .reg_rules = {
                ATH9K_2GHZ_CH01_11,
                ATH9K_2GHZ_CH12_13,
                ATH9K_5GHZ_ALL,
        }
};

static inline bool is_wwr_sku(u16 regd)
{
        return ((regd & WORLD_SKU_MASK) == WORLD_SKU_PREFIX) ||
                (regd == WORLD);
}

static u16 ath_regd_get_eepromRD(struct ath_regulatory *reg)
{
        return reg->current_rd & ~WORLDWIDE_ROAMING_FLAG;
}

bool ath_is_world_regd(struct ath_regulatory *reg)
{
        return is_wwr_sku(ath_regd_get_eepromRD(reg));
}
EXPORT_SYMBOL(ath_is_world_regd);

static const struct ieee80211_regdomain *ath_default_world_regdomain(void)
{
        /* this is the most restrictive */
        return &ath_world_regdom_64;
}

static const struct
ieee80211_regdomain *ath_world_regdomain(struct ath_regulatory *reg)
{
        switch (reg->regpair->regDmnEnum) {
        case 0x60:
        case 0x61:
        case 0x62:
                return &ath_world_regdom_60_61_62;
        case 0x63:
        case 0x65:
                return &ath_world_regdom_63_65;
        case 0x64:
                return &ath_world_regdom_64;
        case 0x66:
        case 0x69:
                return &ath_world_regdom_66_69;
        case 0x67:
        case 0x68:
        case 0x6A:
                return &ath_world_regdom_67_68_6A;
        default:
                WARN_ON(1);
                return ath_default_world_regdomain();
        }
}

/* Frequency is one where radar detection is required */
static bool ath_is_radar_freq(u16 center_freq)
{
        return (center_freq >= 5260 && center_freq <= 5700);
}

/*
 * N.B: These exception rules do not apply radar freqs.
 *
 * - We enable adhoc (or beaconing) if allowed by 11d
 * - We enable active scan if the channel is allowed by 11d
 * - If no country IE has been processed and a we determine we have
 *   received a beacon on a channel we can enable active scan and
 *   adhoc (or beaconing).
 */
static void
ath_reg_apply_beaconing_flags(struct wiphy *wiphy,
                              enum nl80211_reg_initiator initiator)
{
        enum ieee80211_band band;
        struct ieee80211_supported_band *sband;
        const struct ieee80211_reg_rule *reg_rule;
        struct ieee80211_channel *ch;
        unsigned int i;
        u32 bandwidth = 0;
        int r;

        for (band = 0; band < IEEE80211_NUM_BANDS; band++) {

                if (!wiphy->bands[band])
                        continue;

                sband = wiphy->bands[band];

                for (i = 0; i < sband->n_channels; i++) {

                        ch = &sband->channels[i];

                        if (ath_is_radar_freq(ch->center_freq) ||
                            (ch->flags & IEEE80211_CHAN_RADAR))
                                continue;

                        if (initiator == NL80211_REGDOM_SET_BY_COUNTRY_IE) {
                                r = freq_reg_info(wiphy,
                                                  ch->center_freq,
                                                  bandwidth,
                                                  &reg_rule);
                                if (r)
                                        continue;
                                /*
                                 * If 11d had a rule for this channel ensure
                                 * we enable adhoc/beaconing if it allows us to
                                 * use it. Note that we would have disabled it
                                 * by applying our static world regdomain by
                                 * default during init, prior to calling our
                                 * regulatory_hint().
                                 */
                                if (!(reg_rule->flags &
                                    NL80211_RRF_NO_IBSS))
                                        ch->flags &=
                                          ~IEEE80211_CHAN_NO_IBSS;
                                if (!(reg_rule->flags &
                                    NL80211_RRF_PASSIVE_SCAN))
                                        ch->flags &=
                                          ~IEEE80211_CHAN_PASSIVE_SCAN;
                        } else {
                                if (ch->beacon_found)
                                        ch->flags &= ~(IEEE80211_CHAN_NO_IBSS |
                                          IEEE80211_CHAN_PASSIVE_SCAN);
                        }
                }
        }

}

/* Allows active scan scan on Ch 12 and 13 */
static void
ath_reg_apply_active_scan_flags(struct wiphy *wiphy,
                                enum nl80211_reg_initiator initiator)
{
        struct ieee80211_supported_band *sband;
        struct ieee80211_channel *ch;
        const struct ieee80211_reg_rule *reg_rule;
        u32 bandwidth = 0;
        int r;

        sband = wiphy->bands[IEEE80211_BAND_2GHZ];

        /*
         * If no country IE has been received always enable active scan
         * on these channels. This is only done for specific regulatory SKUs
         */
        if (initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE) {
                ch = &sband->channels[11]; /* CH 12 */
                if (ch->flags & IEEE80211_CHAN_PASSIVE_SCAN)
                        ch->flags &= ~IEEE80211_CHAN_PASSIVE_SCAN;
                ch = &sband->channels[12]; /* CH 13 */
                if (ch->flags & IEEE80211_CHAN_PASSIVE_SCAN)
                        ch->flags &= ~IEEE80211_CHAN_PASSIVE_SCAN;
                return;
        }

        /*
         * If a country IE has been recieved check its rule for this
         * channel first before enabling active scan. The passive scan
         * would have been enforced by the initial processing of our
         * custom regulatory domain.
         */

        ch = &sband->channels[11]; /* CH 12 */
        r = freq_reg_info(wiphy, ch->center_freq, bandwidth, &reg_rule);
        if (!r) {
                if (!(reg_rule->flags & NL80211_RRF_PASSIVE_SCAN))
                        if (ch->flags & IEEE80211_CHAN_PASSIVE_SCAN)
                                ch->flags &= ~IEEE80211_CHAN_PASSIVE_SCAN;
        }

        ch = &sband->channels[12]; /* CH 13 */
        r = freq_reg_info(wiphy, ch->center_freq, bandwidth, &reg_rule);
        if (!r) {
                if (!(reg_rule->flags & NL80211_RRF_PASSIVE_SCAN))
                        if (ch->flags & IEEE80211_CHAN_PASSIVE_SCAN)
                                ch->flags &= ~IEEE80211_CHAN_PASSIVE_SCAN;
        }
}

/* Always apply Radar/DFS rules on freq range 5260 MHz - 5700 MHz */
static void ath_reg_apply_radar_flags(struct wiphy *wiphy)
{
        struct ieee80211_supported_band *sband;
        struct ieee80211_channel *ch;
        unsigned int i;

        if (!wiphy->bands[IEEE80211_BAND_5GHZ])
                return;

        sband = wiphy->bands[IEEE80211_BAND_5GHZ];

        for (i = 0; i < sband->n_channels; i++) {
                ch = &sband->channels[i];
                if (!ath_is_radar_freq(ch->center_freq))
                        continue;
                /* We always enable radar detection/DFS on this
                 * frequency range. Additionally we also apply on
                 * this frequency range:
                 * - If STA mode does not yet have DFS supports disable
                 *   active scanning
                 * - If adhoc mode does not support DFS yet then
                 *   disable adhoc in the frequency.
                 * - If AP mode does not yet support radar detection/DFS
                 *   do not allow AP mode
                 */
                if (!(ch->flags & IEEE80211_CHAN_DISABLED))
                        ch->flags |= IEEE80211_CHAN_RADAR |
                                     IEEE80211_CHAN_NO_IBSS |
                                     IEEE80211_CHAN_PASSIVE_SCAN;
        }
}

static void ath_reg_apply_world_flags(struct wiphy *wiphy,
                                      enum nl80211_reg_initiator initiator,
                                      struct ath_regulatory *reg)
{
        switch (reg->regpair->regDmnEnum) {
        case 0x60:
        case 0x63:
        case 0x66:
        case 0x67:
                ath_reg_apply_beaconing_flags(wiphy, initiator);
                break;
        case 0x68:
                ath_reg_apply_beaconing_flags(wiphy, initiator);
                ath_reg_apply_active_scan_flags(wiphy, initiator);
                break;
        }
        return;
}

int ath_reg_notifier_apply(struct wiphy *wiphy,
                           struct regulatory_request *request,
                           struct ath_regulatory *reg)
{
        /* We always apply this */
        ath_reg_apply_radar_flags(wiphy);

        switch (request->initiator) {
        case NL80211_REGDOM_SET_BY_DRIVER:
        case NL80211_REGDOM_SET_BY_CORE:
        case NL80211_REGDOM_SET_BY_USER:
                break;
        case NL80211_REGDOM_SET_BY_COUNTRY_IE:
                if (ath_is_world_regd(reg))
                        ath_reg_apply_world_flags(wiphy, request->initiator,
                                                  reg);
                break;
        }

        return 0;
}
EXPORT_SYMBOL(ath_reg_notifier_apply);

static bool ath_regd_is_eeprom_valid(struct ath_regulatory *reg)
{
         u16 rd = ath_regd_get_eepromRD(reg);
        int i;

        if (rd & COUNTRY_ERD_FLAG) {
                /* EEPROM value is a country code */
                u16 cc = rd & ~COUNTRY_ERD_FLAG;
                printk(KERN_DEBUG
                       "ath: EEPROM indicates we should expect "
                        "a country code\n");
                for (i = 0; i < ARRAY_SIZE(allCountries); i++)
                        if (allCountries[i].countryCode == cc)
                                return true;
        } else {
                /* EEPROM value is a regpair value */
                if (rd != CTRY_DEFAULT)
                        printk(KERN_DEBUG "ath: EEPROM indicates we "
                               "should expect a direct regpair map\n");
                for (i = 0; i < ARRAY_SIZE(regDomainPairs); i++)
                        if (regDomainPairs[i].regDmnEnum == rd)
                                return true;
        }
        printk(KERN_DEBUG
                 "ath: invalid regulatory domain/country code 0x%x\n", rd);
        return false;
}

/* EEPROM country code to regpair mapping */
static struct country_code_to_enum_rd*
ath_regd_find_country(u16 countryCode)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(allCountries); i++) {
                if (allCountries[i].countryCode == countryCode)
                        return &allCountries[i];
        }
        return NULL;
}

/* EEPROM rd code to regpair mapping */
static struct country_code_to_enum_rd*
ath_regd_find_country_by_rd(int regdmn)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(allCountries); i++) {
                if (allCountries[i].regDmnEnum == regdmn)
                        return &allCountries[i];
        }
        return NULL;
}

/* Returns the map of the EEPROM set RD to a country code */
static u16 ath_regd_get_default_country(u16 rd)
{
        if (rd & COUNTRY_ERD_FLAG) {
                struct country_code_to_enum_rd *country = NULL;
                u16 cc = rd & ~COUNTRY_ERD_FLAG;

                country = ath_regd_find_country(cc);
                if (country != NULL)
                        return cc;
        }

        return CTRY_DEFAULT;
}

static struct reg_dmn_pair_mapping*
ath_get_regpair(int regdmn)
{
        int i;

        if (regdmn == NO_ENUMRD)
                return NULL;
        for (i = 0; i < ARRAY_SIZE(regDomainPairs); i++) {
                if (regDomainPairs[i].regDmnEnum == regdmn)
                        return &regDomainPairs[i];
        }
        return NULL;
}

static int
ath_regd_init_wiphy(struct ath_regulatory *reg,
                    struct wiphy *wiphy,
                    int (*reg_notifier)(struct wiphy *wiphy,
                                        struct regulatory_request *request))
{
        const struct ieee80211_regdomain *regd;

        wiphy->reg_notifier = reg_notifier;
        wiphy->strict_regulatory = true;

        if (ath_is_world_regd(reg)) {
                /*
                 * Anything applied here (prior to wiphy registration) gets
                 * saved on the wiphy orig_* parameters
                 */
                regd = ath_world_regdomain(reg);
                wiphy->custom_regulatory = true;
                wiphy->strict_regulatory = false;
        } else {
                /*
                 * This gets applied in the case of the absense of CRDA,
                 * it's our own custom world regulatory domain, similar to
                 * cfg80211's but we enable passive scanning.
                 */
                regd = ath_default_world_regdomain();
        }
        wiphy_apply_custom_regulatory(wiphy, regd);
        ath_reg_apply_radar_flags(wiphy);
        ath_reg_apply_world_flags(wiphy, NL80211_REGDOM_SET_BY_DRIVER, reg);
        return 0;
}

/*
 * Some users have reported their EEPROM programmed with
 * 0x8000 set, this is not a supported regulatory domain
 * but since we have more than one user with it we need
 * a solution for them. We default to 0x64, which is the
 * default Atheros world regulatory domain.
 */
static void ath_regd_sanitize(struct ath_regulatory *reg)
{
        if (reg->current_rd != COUNTRY_ERD_FLAG)
                return;
        printk(KERN_DEBUG "ath: EEPROM regdomain sanitized\n");
        reg->current_rd = 0x64;
}

int
ath_regd_init(struct ath_regulatory *reg,
              struct wiphy *wiphy,
              int (*reg_notifier)(struct wiphy *wiphy,
                                  struct regulatory_request *request))
{
        struct country_code_to_enum_rd *country = NULL;
        u16 regdmn;

        if (!reg)
                return -EINVAL;

        ath_regd_sanitize(reg);

        printk(KERN_DEBUG "ath: EEPROM regdomain: 0x%0x\n", reg->current_rd);

        if (!ath_regd_is_eeprom_valid(reg)) {
                printk(KERN_ERR "ath: Invalid EEPROM contents\n");
                return -EINVAL;
        }

        regdmn = ath_regd_get_eepromRD(reg);
        reg->country_code = ath_regd_get_default_country(regdmn);

        if (reg->country_code == CTRY_DEFAULT &&
            regdmn == CTRY_DEFAULT) {
                printk(KERN_DEBUG "ath: EEPROM indicates default "
                       "country code should be used\n");
                reg->country_code = CTRY_UNITED_STATES;
        }

        if (reg->country_code == CTRY_DEFAULT) {
                country = NULL;
        } else {
                printk(KERN_DEBUG "ath: doing EEPROM country->regdmn "
                       "map search\n");
                country = ath_regd_find_country(reg->country_code);
                if (country == NULL) {
                        printk(KERN_DEBUG
                                "ath: no valid country maps found for "
                                "country code: 0x%0x\n",
                                reg->country_code);
                        return -EINVAL;
                } else {
                        regdmn = country->regDmnEnum;
                        printk(KERN_DEBUG "ath: country maps to "
                               "regdmn code: 0x%0x\n",
                               regdmn);
                }
        }

        reg->regpair = ath_get_regpair(regdmn);

        if (!reg->regpair) {
                printk(KERN_DEBUG "ath: "
                        "No regulatory domain pair found, cannot continue\n");
                return -EINVAL;
        }

        if (!country)
                country = ath_regd_find_country_by_rd(regdmn);

        if (country) {
                reg->alpha2[0] = country->isoName[0];
                reg->alpha2[1] = country->isoName[1];
        } else {
                reg->alpha2[0] = '0';
                reg->alpha2[1] = '0';
        }

        printk(KERN_DEBUG "ath: Country alpha2 being used: %c%c\n",
                reg->alpha2[0], reg->alpha2[1]);
        printk(KERN_DEBUG "ath: Regpair used: 0x%0x\n",
                reg->regpair->regDmnEnum);

        ath_regd_init_wiphy(reg, wiphy, reg_notifier);
        return 0;
}
EXPORT_SYMBOL(ath_regd_init);

u32 ath_regd_get_band_ctl(struct ath_regulatory *reg,
                          enum ieee80211_band band)
{
        if (!reg->regpair ||
            (reg->country_code == CTRY_DEFAULT &&
             is_wwr_sku(ath_regd_get_eepromRD(reg)))) {
                return SD_NO_CTL;
        }

        switch (band) {
        case IEEE80211_BAND_2GHZ:
                return reg->regpair->reg_2ghz_ctl;
        case IEEE80211_BAND_5GHZ:
                return reg->regpair->reg_5ghz_ctl;
        default:
                return NO_CTL;
        }
}
EXPORT_SYMBOL(ath_regd_get_band_ctl);