/*
 * Copyright (c) 2013 Qualcomm Atheros, 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/relay.h>
#include <linux/random.h>
#include "ath9k.h"

static s8 fix_rssi_inv_only(u8 rssi_val)
{
        if (rssi_val == 128)
                rssi_val = 0;
        return (s8) rssi_val;
}

static void ath_debug_send_fft_sample(struct ath_spec_scan_priv *spec_priv,
                                      struct fft_sample_tlv *fft_sample_tlv)
{
        int length;
        if (!spec_priv->rfs_chan_spec_scan)
                return;

        length = __be16_to_cpu(fft_sample_tlv->length) +
                 sizeof(*fft_sample_tlv);
        relay_write(spec_priv->rfs_chan_spec_scan, fft_sample_tlv, length);
}

typedef int (ath_cmn_fft_idx_validator) (u8 *sample_end, int bytes_read);

static int
ath_cmn_max_idx_verify_ht20_fft(u8 *sample_end, int bytes_read)
{
        struct ath_ht20_mag_info *mag_info;
        u8 *sample;
        u16 max_magnitude;
        u8 max_index;
        u8 max_exp;

        /* Sanity check so that we don't read outside the read
         * buffer
         */
        if (bytes_read < SPECTRAL_HT20_SAMPLE_LEN - 1)
                return -1;

        mag_info = (struct ath_ht20_mag_info *) (sample_end -
                                sizeof(struct ath_ht20_mag_info) + 1);

        sample = sample_end - SPECTRAL_HT20_SAMPLE_LEN + 1;

        max_index = spectral_max_index_ht20(mag_info->all_bins);
        max_magnitude = spectral_max_magnitude(mag_info->all_bins);

        max_exp = mag_info->max_exp & 0xf;

        /* Don't try to read something outside the read buffer
         * in case of a missing byte (so bins[0] will be outside
         * the read buffer)
         */
        if (bytes_read < SPECTRAL_HT20_SAMPLE_LEN && max_index < 1)
                return -1;

        if ((sample[max_index] & 0xf8) != ((max_magnitude >> max_exp) & 0xf8))
                return -1;
        else
                return 0;
}

static int
ath_cmn_max_idx_verify_ht20_40_fft(u8 *sample_end, int bytes_read)
{
        struct ath_ht20_40_mag_info *mag_info;
        u8 *sample;
        u16 lower_mag, upper_mag;
        u8 lower_max_index, upper_max_index;
        u8 max_exp;
        int dc_pos = SPECTRAL_HT20_40_NUM_BINS / 2;

        /* Sanity check so that we don't read outside the read
         * buffer
         */
        if (bytes_read < SPECTRAL_HT20_40_SAMPLE_LEN - 1)
                return -1;

        mag_info = (struct ath_ht20_40_mag_info *) (sample_end -
                                sizeof(struct ath_ht20_40_mag_info) + 1);

        sample = sample_end - SPECTRAL_HT20_40_SAMPLE_LEN + 1;

        lower_mag = spectral_max_magnitude(mag_info->lower_bins);
        lower_max_index = spectral_max_index_ht40(mag_info->lower_bins);

        upper_mag = spectral_max_magnitude(mag_info->upper_bins);
        upper_max_index = spectral_max_index_ht40(mag_info->upper_bins);

        max_exp = mag_info->max_exp & 0xf;

        /* Don't try to read something outside the read buffer
         * in case of a missing byte (so bins[0] will be outside
         * the read buffer)
         */
        if (bytes_read < SPECTRAL_HT20_40_SAMPLE_LEN &&
           ((upper_max_index < 1) || (lower_max_index < 1)))
                return -1;

        if (((sample[upper_max_index + dc_pos] & 0xf8) !=
             ((upper_mag >> max_exp) & 0xf8)) ||
            ((sample[lower_max_index] & 0xf8) !=
             ((lower_mag >> max_exp) & 0xf8)))
                return -1;
        else
                return 0;
}

typedef int (ath_cmn_fft_sample_handler) (struct ath_rx_status *rs,
                        struct ath_spec_scan_priv *spec_priv,
                        u8 *sample_buf, u64 tsf, u16 freq, int chan_type);

static int
ath_cmn_process_ht20_fft(struct ath_rx_status *rs,
                        struct ath_spec_scan_priv *spec_priv,
                        u8 *sample_buf,
                        u64 tsf, u16 freq, int chan_type)
{
        struct fft_sample_ht20 fft_sample_20;
        struct ath_common *common = ath9k_hw_common(spec_priv->ah);
        struct ath_hw *ah = spec_priv->ah;
        struct ath_ht20_mag_info *mag_info;
        struct fft_sample_tlv *tlv;
        int i = 0;
        int ret = 0;
        int dc_pos = SPECTRAL_HT20_NUM_BINS / 2;
        u16 magnitude, tmp_mag, length;
        u8 max_index, bitmap_w, max_exp;

        length = sizeof(fft_sample_20) - sizeof(struct fft_sample_tlv);
        fft_sample_20.tlv.type = ATH_FFT_SAMPLE_HT20;
        fft_sample_20.tlv.length = __cpu_to_be16(length);
        fft_sample_20.freq = __cpu_to_be16(freq);
        fft_sample_20.rssi = fix_rssi_inv_only(rs->rs_rssi_ctl[0]);
        fft_sample_20.noise = ah->noise;

        mag_info = (struct ath_ht20_mag_info *) (sample_buf +
                                        SPECTRAL_HT20_NUM_BINS);

        magnitude = spectral_max_magnitude(mag_info->all_bins);
        fft_sample_20.max_magnitude = __cpu_to_be16(magnitude);

        max_index = spectral_max_index_ht20(mag_info->all_bins);
        fft_sample_20.max_index = max_index;

        bitmap_w = spectral_bitmap_weight(mag_info->all_bins);
        fft_sample_20.bitmap_weight = bitmap_w;

        max_exp = mag_info->max_exp & 0xf;
        fft_sample_20.max_exp = max_exp;

        fft_sample_20.tsf = __cpu_to_be64(tsf);

        memcpy(fft_sample_20.data, sample_buf, SPECTRAL_HT20_NUM_BINS);

        ath_dbg(common, SPECTRAL_SCAN, "FFT HT20 frame: max mag 0x%X,"
                                        "max_mag_idx %i\n",
                                        magnitude >> max_exp,
                                        max_index);

        if ((fft_sample_20.data[max_index] & 0xf8) !=
            ((magnitude >> max_exp) & 0xf8)) {
                ath_dbg(common, SPECTRAL_SCAN, "Magnitude mismatch !\n");
                ret = -1;
        }

        /* DC value (value in the middle) is the blind spot of the spectral
         * sample and invalid, interpolate it.
         */
        fft_sample_20.data[dc_pos] = (fft_sample_20.data[dc_pos + 1] +
                                        fft_sample_20.data[dc_pos - 1]) / 2;

        /* Check if the maximum magnitude is indeed maximum,
         * also if the maximum value was at dc_pos, calculate
         * a new one (since value at dc_pos is invalid).
         */
        if (max_index == dc_pos) {
                tmp_mag = 0;
                for (i = 0; i < dc_pos; i++) {
                        if (fft_sample_20.data[i] > tmp_mag) {
                                tmp_mag = fft_sample_20.data[i];
                                fft_sample_20.max_index = i;
                        }
                }

                magnitude = tmp_mag << max_exp;
                fft_sample_20.max_magnitude = __cpu_to_be16(magnitude);

                ath_dbg(common, SPECTRAL_SCAN,
                        "Calculated new lower max 0x%X at %i\n",
                        tmp_mag, fft_sample_20.max_index);
        } else
        for (i = 0; i < SPECTRAL_HT20_NUM_BINS; i++) {
                if (fft_sample_20.data[i] == (magnitude >> max_exp))
                        ath_dbg(common, SPECTRAL_SCAN,
                                "Got max: 0x%X at index %i\n",
                                fft_sample_20.data[i], i);

                if (fft_sample_20.data[i] > (magnitude >> max_exp)) {
                        ath_dbg(common, SPECTRAL_SCAN,
                                "Got bin %i greater than max: 0x%X\n",
                                i, fft_sample_20.data[i]);
                        ret = -1;
                }
        }

        if (ret < 0)
                return ret;

        tlv = (struct fft_sample_tlv *)&fft_sample_20;

        ath_debug_send_fft_sample(spec_priv, tlv);

        return 0;
}

static int
ath_cmn_process_ht20_40_fft(struct ath_rx_status *rs,
                        struct ath_spec_scan_priv *spec_priv,
                        u8 *sample_buf,
                        u64 tsf, u16 freq, int chan_type)
{
        struct fft_sample_ht20_40 fft_sample_40;
        struct ath_common *common = ath9k_hw_common(spec_priv->ah);
        struct ath_hw *ah = spec_priv->ah;
        struct ath9k_hw_cal_data *caldata = ah->caldata;
        struct ath_ht20_40_mag_info *mag_info;
        struct fft_sample_tlv *tlv;
        int dc_pos = SPECTRAL_HT20_40_NUM_BINS / 2;
        int i = 0;
        int ret = 0;
        s16 ext_nf;
        u16 lower_mag, upper_mag, tmp_mag, length;
        s8 lower_rssi, upper_rssi;
        u8 lower_max_index, upper_max_index;
        u8 lower_bitmap_w, upper_bitmap_w, max_exp;

        if (caldata)
                ext_nf = ath9k_hw_getchan_noise(ah, ah->curchan,
                                caldata->nfCalHist[3].privNF);
        else
                ext_nf = ATH_DEFAULT_NOISE_FLOOR;

        length = sizeof(fft_sample_40) - sizeof(struct fft_sample_tlv);
        fft_sample_40.tlv.type = ATH_FFT_SAMPLE_HT20_40;
        fft_sample_40.tlv.length = __cpu_to_be16(length);
        fft_sample_40.freq = __cpu_to_be16(freq);
        fft_sample_40.channel_type = chan_type;

        if (chan_type == NL80211_CHAN_HT40PLUS) {
                lower_rssi = fix_rssi_inv_only(rs->rs_rssi_ctl[0]);
                upper_rssi = fix_rssi_inv_only(rs->rs_rssi_ext[0]);

                fft_sample_40.lower_noise = ah->noise;
                fft_sample_40.upper_noise = ext_nf;
        } else {
                lower_rssi = fix_rssi_inv_only(rs->rs_rssi_ext[0]);
                upper_rssi = fix_rssi_inv_only(rs->rs_rssi_ctl[0]);

                fft_sample_40.lower_noise = ext_nf;
                fft_sample_40.upper_noise = ah->noise;
        }

        fft_sample_40.lower_rssi = lower_rssi;
        fft_sample_40.upper_rssi = upper_rssi;

        mag_info = (struct ath_ht20_40_mag_info *) (sample_buf +
                                        SPECTRAL_HT20_40_NUM_BINS);

        lower_mag = spectral_max_magnitude(mag_info->lower_bins);
        fft_sample_40.lower_max_magnitude = __cpu_to_be16(lower_mag);

        upper_mag = spectral_max_magnitude(mag_info->upper_bins);
        fft_sample_40.upper_max_magnitude = __cpu_to_be16(upper_mag);

        lower_max_index = spectral_max_index_ht40(mag_info->lower_bins);
        fft_sample_40.lower_max_index = lower_max_index;

        upper_max_index = spectral_max_index_ht40(mag_info->upper_bins);
        fft_sample_40.upper_max_index = upper_max_index;

        lower_bitmap_w = spectral_bitmap_weight(mag_info->lower_bins);
        fft_sample_40.lower_bitmap_weight = lower_bitmap_w;

        upper_bitmap_w = spectral_bitmap_weight(mag_info->upper_bins);
        fft_sample_40.upper_bitmap_weight = upper_bitmap_w;

        max_exp = mag_info->max_exp & 0xf;
        fft_sample_40.max_exp = max_exp;

        fft_sample_40.tsf = __cpu_to_be64(tsf);

        memcpy(fft_sample_40.data, sample_buf, SPECTRAL_HT20_40_NUM_BINS);

        ath_dbg(common, SPECTRAL_SCAN, "FFT HT20/40 frame: lower mag 0x%X,"
                                        "lower_mag_idx %i, upper mag 0x%X,"
                                        "upper_mag_idx %i\n",
                                        lower_mag >> max_exp,
                                        lower_max_index,
                                        upper_mag >> max_exp,
                                        upper_max_index);

        /* Check if we got the expected magnitude values at
         * the expected bins
         */
        if (((fft_sample_40.data[upper_max_index + dc_pos] & 0xf8)
            != ((upper_mag >> max_exp) & 0xf8)) ||
           ((fft_sample_40.data[lower_max_index] & 0xf8)
            != ((lower_mag >> max_exp) & 0xf8))) {
                ath_dbg(common, SPECTRAL_SCAN, "Magnitude mismatch !\n");
                ret = -1;
        }

        /* DC value (value in the middle) is the blind spot of the spectral
         * sample and invalid, interpolate it.
         */
        fft_sample_40.data[dc_pos] = (fft_sample_40.data[dc_pos + 1] +
                                        fft_sample_40.data[dc_pos - 1]) / 2;

        /* Check if the maximum magnitudes are indeed maximum,
         * also if the maximum value was at dc_pos, calculate
         * a new one (since value at dc_pos is invalid).
         */
        if (lower_max_index == dc_pos) {
                tmp_mag = 0;
                for (i = 0; i < dc_pos; i++) {
                        if (fft_sample_40.data[i] > tmp_mag) {
                                tmp_mag = fft_sample_40.data[i];
                                fft_sample_40.lower_max_index = i;
                        }
                }

                lower_mag = tmp_mag << max_exp;
                fft_sample_40.lower_max_magnitude = __cpu_to_be16(lower_mag);

                ath_dbg(common, SPECTRAL_SCAN,
                        "Calculated new lower max 0x%X at %i\n",
                        tmp_mag, fft_sample_40.lower_max_index);
        } else
        for (i = 0; i < dc_pos; i++) {
                if (fft_sample_40.data[i] == (lower_mag >> max_exp))
                        ath_dbg(common, SPECTRAL_SCAN,
                                "Got lower mag: 0x%X at index %i\n",
                                fft_sample_40.data[i], i);

                if (fft_sample_40.data[i] > (lower_mag >> max_exp)) {
                        ath_dbg(common, SPECTRAL_SCAN,
                                "Got lower bin %i higher than max: 0x%X\n",
                                i, fft_sample_40.data[i]);
                        ret = -1;
                }
        }

        if (upper_max_index == dc_pos) {
                tmp_mag = 0;
                for (i = dc_pos; i < SPECTRAL_HT20_40_NUM_BINS; i++) {
                        if (fft_sample_40.data[i] > tmp_mag) {
                                tmp_mag = fft_sample_40.data[i];
                                fft_sample_40.upper_max_index = i;
                        }
                }
                upper_mag = tmp_mag << max_exp;
                fft_sample_40.upper_max_magnitude = __cpu_to_be16(upper_mag);

                ath_dbg(common, SPECTRAL_SCAN,
                        "Calculated new upper max 0x%X at %i\n",
                        tmp_mag, fft_sample_40.upper_max_index);
        } else
        for (i = dc_pos; i < SPECTRAL_HT20_40_NUM_BINS; i++) {
                if (fft_sample_40.data[i] == (upper_mag >> max_exp))
                        ath_dbg(common, SPECTRAL_SCAN,
                                "Got upper mag: 0x%X at index %i\n",
                                fft_sample_40.data[i], i);

                if (fft_sample_40.data[i] > (upper_mag >> max_exp)) {
                        ath_dbg(common, SPECTRAL_SCAN,
                                "Got upper bin %i higher than max: 0x%X\n",
                                i, fft_sample_40.data[i]);

                        ret = -1;
                }
        }

        if (ret < 0)
                return ret;

        tlv = (struct fft_sample_tlv *)&fft_sample_40;

        ath_debug_send_fft_sample(spec_priv, tlv);

        return 0;
}

static inline void
ath_cmn_copy_fft_frame(u8 *in, u8 *out, int sample_len, int sample_bytes)
{
        switch (sample_bytes - sample_len) {
        case -1:
                /* First byte missing */
                memcpy(&out[1], in,
                       sample_len - 1);
                break;
        case 0:
                /* Length correct, nothing to do. */
                memcpy(out, in, sample_len);
                break;
        case 1:
                /* MAC added 2 extra bytes AND first byte
                 * is missing.
                 */
                memcpy(&out[1], in, 30);
                out[31] = in[31];
                memcpy(&out[32], &in[33],
                       sample_len - 32);
                break;
        case 2:
                /* MAC added 2 extra bytes at bin 30 and 32,
                 * remove them.
                 */
                memcpy(out, in, 30);
                out[30] = in[31];
                memcpy(&out[31], &in[33],
                       sample_len - 31);
                break;
        default:
                break;
        }
}

static int
ath_cmn_is_fft_buf_full(struct ath_spec_scan_priv *spec_priv)
{
        int i = 0;
        int ret = 0;
        struct rchan_buf *buf;
        struct rchan *rc = spec_priv->rfs_chan_spec_scan;

        for_each_possible_cpu(i) {
                if ((buf = *per_cpu_ptr(rc->buf, i))) {
                        ret += relay_buf_full(buf);
                }
        }

        if (ret)
                return 1;
        else
                return 0;
}

/* returns 1 if this was a spectral frame, even if not handled. */
int ath_cmn_process_fft(struct ath_spec_scan_priv *spec_priv, struct ieee80211_hdr *hdr,
                    struct ath_rx_status *rs, u64 tsf)
{
        u8 sample_buf[SPECTRAL_SAMPLE_MAX_LEN] = {0};
        struct ath_hw *ah = spec_priv->ah;
        struct ath_common *common = ath9k_hw_common(spec_priv->ah);
        struct ath_softc *sc = (struct ath_softc *)common->priv;
        u8 num_bins, *vdata = (u8 *)hdr;
        struct ath_radar_info *radar_info;
        int len = rs->rs_datalen;
        int i;
        int got_slen = 0;
        u8  *sample_start;
        int sample_bytes = 0;
        int ret = 0;
        u16 fft_len, sample_len, freq = ah->curchan->chan->center_freq;
        enum nl80211_channel_type chan_type;
        ath_cmn_fft_idx_validator *fft_idx_validator;
        ath_cmn_fft_sample_handler *fft_handler;

        /* AR9280 and before report via ATH9K_PHYERR_RADAR, AR93xx and newer
         * via ATH9K_PHYERR_SPECTRAL. Haven't seen ATH9K_PHYERR_FALSE_RADAR_EXT
         * yet, but this is supposed to be possible as well.
         */
        if (rs->rs_phyerr != ATH9K_PHYERR_RADAR &&
            rs->rs_phyerr != ATH9K_PHYERR_FALSE_RADAR_EXT &&
            rs->rs_phyerr != ATH9K_PHYERR_SPECTRAL)
                return 0;

        /* check if spectral scan bit is set. This does not have to be checked
         * if received through a SPECTRAL phy error, but shouldn't hurt.
         */
        radar_info = ((struct ath_radar_info *)&vdata[len]) - 1;
        if (!(radar_info->pulse_bw_info & SPECTRAL_SCAN_BITMASK))
                return 0;

        if (!spec_priv->rfs_chan_spec_scan)
                return 1;

        /* Output buffers are full, no need to process anything
         * since there is no space to put the result anyway
         */
        ret = ath_cmn_is_fft_buf_full(spec_priv);
        if (ret == 1) {
                ath_dbg(common, SPECTRAL_SCAN, "FFT report ignored, no space "
                                                "left on output buffers\n");
                return 1;
        }

        chan_type = cfg80211_get_chandef_type(&common->hw->conf.chandef);
        if ((chan_type == NL80211_CHAN_HT40MINUS) ||
            (chan_type == NL80211_CHAN_HT40PLUS)) {
                fft_len = SPECTRAL_HT20_40_TOTAL_DATA_LEN;
                sample_len = SPECTRAL_HT20_40_SAMPLE_LEN;
                num_bins = SPECTRAL_HT20_40_NUM_BINS;
                fft_idx_validator = &ath_cmn_max_idx_verify_ht20_40_fft;
                fft_handler = &ath_cmn_process_ht20_40_fft;
        } else {
                fft_len = SPECTRAL_HT20_TOTAL_DATA_LEN;
                sample_len = SPECTRAL_HT20_SAMPLE_LEN;
                num_bins = SPECTRAL_HT20_NUM_BINS;
                fft_idx_validator = ath_cmn_max_idx_verify_ht20_fft;
                fft_handler = &ath_cmn_process_ht20_fft;
        }

        ath_dbg(common, SPECTRAL_SCAN, "Got radar dump bw_info: 0x%X,"
                                        "len: %i fft_len: %i\n",
                                        radar_info->pulse_bw_info,
                                        len,
                                        fft_len);
        sample_start = vdata;
        for (i = 0; i < len - 2; i++) {
                sample_bytes++;

                /* Only a single sample received, no need to look
                 * for the sample's end, do the correction based
                 * on the packet's length instead. Note that hw
                 * will always put the radar_info structure on
                 * the end.
                 */
                if (len <= fft_len + 2) {
                        sample_bytes = len - sizeof(struct ath_radar_info);
                        got_slen = 1;
                }

                /* Search for the end of the FFT frame between
                 * sample_len - 1 and sample_len + 2. exp_max is 3
                 * bits long and it's the only value on the last
                 * byte of the frame so since it'll be smaller than
                 * the next byte (the first bin of the next sample)
                 * 90% of the time, we can use it as a separator.
                 */
                if (vdata[i] <= 0x7 && sample_bytes >= sample_len - 1) {

                        /* Got a frame length within boundaries, there are
                         * four scenarios here:
                         *
                         * a) sample_len -> We got the correct length
                         * b) sample_len + 2 -> 2 bytes added around bin[31]
                         * c) sample_len - 1 -> The first byte is missing
                         * d) sample_len + 1 -> b + c at the same time
                         *
                         * When MAC adds 2 extra bytes, bin[31] and bin[32]
                         * have the same value, so we can use that for further
                         * verification in cases b and d.
                         */

                        /* Did we go too far ? If so we couldn't determine
                         * this sample's boundaries, discard any further
                         * data
                         */
                        if ((sample_bytes > sample_len + 2) ||
                           ((sample_bytes > sample_len) &&
                           (sample_start[31] != sample_start[32])))
                                break;

                        /* See if we got a valid frame by checking the
                         * consistency of mag_info fields. This is to
                         * prevent from "fixing" a correct frame.
                         * Failure is non-fatal, later frames may
                         * be valid.
                         */
                        if (!fft_idx_validator(&vdata[i], i)) {
                                ath_dbg(common, SPECTRAL_SCAN,
                                        "Found valid fft frame at %i\n", i);
                                got_slen = 1;
                        }

                        /* We expect 1 - 2 more bytes */
                        else if ((sample_start[31] == sample_start[32]) &&
                                (sample_bytes >= sample_len) &&
                                (sample_bytes < sample_len + 2) &&
                                (vdata[i + 1] <= 0x7))
                                continue;

                        /* Try to distinguish cases a and c */
                        else if ((sample_bytes == sample_len - 1) &&
                                (vdata[i + 1] <= 0x7))
                                continue;

                        got_slen = 1;
                }

                if (got_slen) {
                        ath_dbg(common, SPECTRAL_SCAN, "FFT frame len: %i\n",
                                sample_bytes);

                        /* Only try to fix a frame if it's the only one
                         * on the report, else just skip it.
                         */
                        if (sample_bytes != sample_len && len <= fft_len + 2) {
                                ath_cmn_copy_fft_frame(sample_start,
                                                       sample_buf, sample_len,
                                                       sample_bytes);

                                ret = fft_handler(rs, spec_priv, sample_buf,
                                                  tsf, freq, chan_type);

                                if (ret == 0)
                                        RX_STAT_INC(sc, rx_spectral_sample_good);
                                else
                                        RX_STAT_INC(sc, rx_spectral_sample_err);

                                memset(sample_buf, 0, SPECTRAL_SAMPLE_MAX_LEN);

                                /* Mix the received bins to the /dev/random
                                 * pool
                                 */
                                add_device_randomness(sample_buf, num_bins);
                        }

                        /* Process a normal frame */
                        if (sample_bytes == sample_len) {
                                ret = fft_handler(rs, spec_priv, sample_start,
                                                  tsf, freq, chan_type);

                                if (ret == 0)
                                        RX_STAT_INC(sc, rx_spectral_sample_good);
                                else
                                        RX_STAT_INC(sc, rx_spectral_sample_err);

                                /* Mix the received bins to the /dev/random
                                 * pool
                                 */
                                add_device_randomness(sample_start, num_bins);
                        }

                        /* Short report processed, break out of the
                         * loop.
                         */
                        if (len <= fft_len + 2)
                                return 1;

                        sample_start = &vdata[i + 1];

                        /* -1 to grab sample_len -1, -2 since
                         * they 'll get increased by one. In case
                         * of failure try to recover by going byte
                         * by byte instead.
                         */
                        if (ret == 0) {
                                i += num_bins - 2;
                                sample_bytes = num_bins - 2;
                        }
                        got_slen = 0;
                }
        }

        i -= num_bins - 2;
        if (len - i != sizeof(struct ath_radar_info))
                ath_dbg(common, SPECTRAL_SCAN, "FFT report truncated"
                                                "(bytes left: %i)\n",
                                                len - i);
        return 1;
}
EXPORT_SYMBOL(ath_cmn_process_fft);

/*********************/
/* spectral_scan_ctl */
/*********************/

static ssize_t read_file_spec_scan_ctl(struct file *file, char __user *user_buf,
                                       size_t count, loff_t *ppos)
{
        struct ath_spec_scan_priv *spec_priv = file->private_data;
        char *mode = "";
        unsigned int len;

        switch (spec_priv->spectral_mode) {
        case SPECTRAL_DISABLED:
                mode = "disable";
                break;
        case SPECTRAL_BACKGROUND:
                mode = "background";
                break;
        case SPECTRAL_CHANSCAN:
                mode = "chanscan";
                break;
        case SPECTRAL_MANUAL:
                mode = "manual";
                break;
        }
        len = strlen(mode);
        return simple_read_from_buffer(user_buf, count, ppos, mode, len);
}

void ath9k_cmn_spectral_scan_trigger(struct ath_common *common,
                                 struct ath_spec_scan_priv *spec_priv)
{
        struct ath_hw *ah = spec_priv->ah;
        u32 rxfilter;

        if (IS_ENABLED(CONFIG_ATH9K_TX99))
                return;

        if (!ath9k_hw_ops(ah)->spectral_scan_trigger) {
                ath_err(common, "spectrum analyzer not implemented on this hardware\n");
                return;
        }

        if (!spec_priv->spec_config.enabled)
                return;

        ath_ps_ops(common)->wakeup(common);
        rxfilter = ath9k_hw_getrxfilter(ah);
        ath9k_hw_setrxfilter(ah, rxfilter |
                                 ATH9K_RX_FILTER_PHYRADAR |
                                 ATH9K_RX_FILTER_PHYERR);

        /* TODO: usually this should not be neccesary, but for some reason
         * (or in some mode?) the trigger must be called after the
         * configuration, otherwise the register will have its values reset
         * (on my ar9220 to value 0x01002310)
         */
        ath9k_cmn_spectral_scan_config(common, spec_priv, spec_priv->spectral_mode);
        ath9k_hw_ops(ah)->spectral_scan_trigger(ah);
        ath_ps_ops(common)->restore(common);
}
EXPORT_SYMBOL(ath9k_cmn_spectral_scan_trigger);

int ath9k_cmn_spectral_scan_config(struct ath_common *common,
                               struct ath_spec_scan_priv *spec_priv,
                               enum spectral_mode spectral_mode)
{
        struct ath_hw *ah = spec_priv->ah;

        if (!ath9k_hw_ops(ah)->spectral_scan_trigger) {
                ath_err(common, "spectrum analyzer not implemented on this hardware\n");
                return -1;
        }

        switch (spectral_mode) {
        case SPECTRAL_DISABLED:
                spec_priv->spec_config.enabled = 0;
                break;
        case SPECTRAL_BACKGROUND:
                /* send endless samples.
                 * TODO: is this really useful for "background"?
                 */
                spec_priv->spec_config.endless = 1;
                spec_priv->spec_config.enabled = 1;
                break;
        case SPECTRAL_CHANSCAN:
        case SPECTRAL_MANUAL:
                spec_priv->spec_config.endless = 0;
                spec_priv->spec_config.enabled = 1;
                break;
        default:
                return -1;
        }

        ath_ps_ops(common)->wakeup(common);
        ath9k_hw_ops(ah)->spectral_scan_config(ah, &spec_priv->spec_config);
        ath_ps_ops(common)->restore(common);

        spec_priv->spectral_mode = spectral_mode;

        return 0;
}
EXPORT_SYMBOL(ath9k_cmn_spectral_scan_config);

static ssize_t write_file_spec_scan_ctl(struct file *file,
                                        const char __user *user_buf,
                                        size_t count, loff_t *ppos)
{
        struct ath_spec_scan_priv *spec_priv = file->private_data;
        struct ath_common *common = ath9k_hw_common(spec_priv->ah);
        char buf[32];
        ssize_t len;

        if (IS_ENABLED(CONFIG_ATH9K_TX99))
                return -EOPNOTSUPP;

        len = min(count, sizeof(buf) - 1);
        if (copy_from_user(buf, user_buf, len))
                return -EFAULT;

        buf[len] = '\0';

        if (strncmp("trigger", buf, 7) == 0) {
                ath9k_cmn_spectral_scan_trigger(common, spec_priv);
        } else if (strncmp("background", buf, 10) == 0) {
                ath9k_cmn_spectral_scan_config(common, spec_priv, SPECTRAL_BACKGROUND);
                ath_dbg(common, CONFIG, "spectral scan: background mode enabled\n");
        } else if (strncmp("chanscan", buf, 8) == 0) {
                ath9k_cmn_spectral_scan_config(common, spec_priv, SPECTRAL_CHANSCAN);
                ath_dbg(common, CONFIG, "spectral scan: channel scan mode enabled\n");
        } else if (strncmp("manual", buf, 6) == 0) {
                ath9k_cmn_spectral_scan_config(common, spec_priv, SPECTRAL_MANUAL);
                ath_dbg(common, CONFIG, "spectral scan: manual mode enabled\n");
        } else if (strncmp("disable", buf, 7) == 0) {
                ath9k_cmn_spectral_scan_config(common, spec_priv, SPECTRAL_DISABLED);
                ath_dbg(common, CONFIG, "spectral scan: disabled\n");
        } else {
                return -EINVAL;
        }

        return count;
}

static const struct file_operations fops_spec_scan_ctl = {
        .read = read_file_spec_scan_ctl,
        .write = write_file_spec_scan_ctl,
        .open = simple_open,
        .owner = THIS_MODULE,
        .llseek = default_llseek,
};

/*************************/
/* spectral_short_repeat */
/*************************/

static ssize_t read_file_spectral_short_repeat(struct file *file,
                                               char __user *user_buf,
                                               size_t count, loff_t *ppos)
{
        struct ath_spec_scan_priv *spec_priv = file->private_data;
        char buf[32];
        unsigned int len;

        len = sprintf(buf, "%d\n", spec_priv->spec_config.short_repeat);
        return simple_read_from_buffer(user_buf, count, ppos, buf, len);
}

static ssize_t write_file_spectral_short_repeat(struct file *file,
                                                const char __user *user_buf,
                                                size_t count, loff_t *ppos)
{
        struct ath_spec_scan_priv *spec_priv = file->private_data;
        unsigned long val;
        char buf[32];
        ssize_t len;

        len = min(count, sizeof(buf) - 1);
        if (copy_from_user(buf, user_buf, len))
                return -EFAULT;

        buf[len] = '\0';
        if (kstrtoul(buf, 0, &val))
                return -EINVAL;

        if (val > 1)
                return -EINVAL;

        spec_priv->spec_config.short_repeat = val;
        return count;
}

static const struct file_operations fops_spectral_short_repeat = {
        .read = read_file_spectral_short_repeat,
        .write = write_file_spectral_short_repeat,
        .open = simple_open,
        .owner = THIS_MODULE,
        .llseek = default_llseek,
};

/******************/
/* spectral_count */
/******************/

static ssize_t read_file_spectral_count(struct file *file,
                                        char __user *user_buf,
                                        size_t count, loff_t *ppos)
{
        struct ath_spec_scan_priv *spec_priv = file->private_data;
        char buf[32];
        unsigned int len;

        len = sprintf(buf, "%d\n", spec_priv->spec_config.count);
        return simple_read_from_buffer(user_buf, count, ppos, buf, len);
}

static ssize_t write_file_spectral_count(struct file *file,
                                         const char __user *user_buf,
                                         size_t count, loff_t *ppos)
{
        struct ath_spec_scan_priv *spec_priv = file->private_data;
        unsigned long val;
        char buf[32];
        ssize_t len;

        len = min(count, sizeof(buf) - 1);
        if (copy_from_user(buf, user_buf, len))
                return -EFAULT;

        buf[len] = '\0';
        if (kstrtoul(buf, 0, &val))
                return -EINVAL;

        if (val > 255)
                return -EINVAL;

        spec_priv->spec_config.count = val;
        return count;
}

static const struct file_operations fops_spectral_count = {
        .read = read_file_spectral_count,
        .write = write_file_spectral_count,
        .open = simple_open,
        .owner = THIS_MODULE,
        .llseek = default_llseek,
};

/*******************/
/* spectral_period */
/*******************/

static ssize_t read_file_spectral_period(struct file *file,
                                         char __user *user_buf,
                                         size_t count, loff_t *ppos)
{
        struct ath_spec_scan_priv *spec_priv = file->private_data;
        char buf[32];
        unsigned int len;

        len = sprintf(buf, "%d\n", spec_priv->spec_config.period);
        return simple_read_from_buffer(user_buf, count, ppos, buf, len);
}

static ssize_t write_file_spectral_period(struct file *file,
                                          const char __user *user_buf,
                                          size_t count, loff_t *ppos)
{
        struct ath_spec_scan_priv *spec_priv = file->private_data;
        unsigned long val;
        char buf[32];
        ssize_t len;

        len = min(count, sizeof(buf) - 1);
        if (copy_from_user(buf, user_buf, len))
                return -EFAULT;

        buf[len] = '\0';
        if (kstrtoul(buf, 0, &val))
                return -EINVAL;

        if (val > 255)
                return -EINVAL;

        spec_priv->spec_config.period = val;
        return count;
}

static const struct file_operations fops_spectral_period = {
        .read = read_file_spectral_period,
        .write = write_file_spectral_period,
        .open = simple_open,
        .owner = THIS_MODULE,
        .llseek = default_llseek,
};

/***********************/
/* spectral_fft_period */
/***********************/

static ssize_t read_file_spectral_fft_period(struct file *file,
                                             char __user *user_buf,
                                             size_t count, loff_t *ppos)
{
        struct ath_spec_scan_priv *spec_priv = file->private_data;
        char buf[32];
        unsigned int len;

        len = sprintf(buf, "%d\n", spec_priv->spec_config.fft_period);
        return simple_read_from_buffer(user_buf, count, ppos, buf, len);
}

static ssize_t write_file_spectral_fft_period(struct file *file,
                                              const char __user *user_buf,
                                              size_t count, loff_t *ppos)
{
        struct ath_spec_scan_priv *spec_priv = file->private_data;

        unsigned long val;
        char buf[32];
        ssize_t len;

        len = min(count, sizeof(buf) - 1);
        if (copy_from_user(buf, user_buf, len))
                return -EFAULT;

        buf[len] = '\0';
        if (kstrtoul(buf, 0, &val))
                return -EINVAL;

        if (val > 15)
                return -EINVAL;

        spec_priv->spec_config.fft_period = val;
        return count;
}

static const struct file_operations fops_spectral_fft_period = {
        .read = read_file_spectral_fft_period,
        .write = write_file_spectral_fft_period,
        .open = simple_open,
        .owner = THIS_MODULE,
        .llseek = default_llseek,
};

/*******************/
/* Relay interface */
/*******************/

static struct dentry *create_buf_file_handler(const char *filename,
                                              struct dentry *parent,
                                              umode_t mode,
                                              struct rchan_buf *buf,
                                              int *is_global)
{
        struct dentry *buf_file;

        buf_file = debugfs_create_file(filename, mode, parent, buf,
                                       &relay_file_operations);
        if (IS_ERR(buf_file))
                return NULL;

        *is_global = 1;
        return buf_file;
}

static int remove_buf_file_handler(struct dentry *dentry)
{
        debugfs_remove(dentry);

        return 0;
}

static struct rchan_callbacks rfs_spec_scan_cb = {
        .create_buf_file = create_buf_file_handler,
        .remove_buf_file = remove_buf_file_handler,
};

/*********************/
/* Debug Init/Deinit */
/*********************/

void ath9k_cmn_spectral_deinit_debug(struct ath_spec_scan_priv *spec_priv)
{
        if (spec_priv->rfs_chan_spec_scan) {
                relay_close(spec_priv->rfs_chan_spec_scan);
                spec_priv->rfs_chan_spec_scan = NULL;
        }
}
EXPORT_SYMBOL(ath9k_cmn_spectral_deinit_debug);

void ath9k_cmn_spectral_init_debug(struct ath_spec_scan_priv *spec_priv,
                                   struct dentry *debugfs_phy)
{
        spec_priv->rfs_chan_spec_scan = relay_open("spectral_scan",
                                            debugfs_phy,
                                            1024, 256, &rfs_spec_scan_cb,
                                            NULL);
        if (!spec_priv->rfs_chan_spec_scan)
                return;

        debugfs_create_file("spectral_scan_ctl",
                            0600,
                            debugfs_phy, spec_priv,
                            &fops_spec_scan_ctl);
        debugfs_create_file("spectral_short_repeat",
                            0600,
                            debugfs_phy, spec_priv,
                            &fops_spectral_short_repeat);
        debugfs_create_file("spectral_count",
                            0600,
                            debugfs_phy, spec_priv,
                            &fops_spectral_count);
        debugfs_create_file("spectral_period",
                            0600,
                            debugfs_phy, spec_priv,
                            &fops_spectral_period);
        debugfs_create_file("spectral_fft_period",
                            0600,
                            debugfs_phy, spec_priv,
                            &fops_spectral_fft_period);
}
EXPORT_SYMBOL(ath9k_cmn_spectral_init_debug);