diff options
Diffstat (limited to 'drivers/net/wireless/ath/ath9k/dfs.c')
| -rw-r--r-- | drivers/net/wireless/ath/ath9k/dfs.c | 170 |
1 files changed, 163 insertions, 7 deletions
diff --git a/drivers/net/wireless/ath/ath9k/dfs.c b/drivers/net/wireless/ath/ath9k/dfs.c index e98a9eaba7ff..1ece42c2443d 100644 --- a/drivers/net/wireless/ath/ath9k/dfs.c +++ b/drivers/net/wireless/ath/ath9k/dfs.c @@ -30,6 +30,157 @@ struct ath_radar_data { u8 pulse_length_pri; }; +/**** begin: CHIRP ************************************************************/ + +/* min and max gradients for defined FCC chirping pulses, given by + * - 20MHz chirp width over a pulse width of 50us + * - 5MHz chirp width over a pulse width of 100us + */ +static const int BIN_DELTA_MIN = 1; +static const int BIN_DELTA_MAX = 10; + +/* we need at least 3 deltas / 4 samples for a reliable chirp detection */ +#define NUM_DIFFS 3 +static const int FFT_NUM_SAMPLES = (NUM_DIFFS + 1); + +/* Threshold for difference of delta peaks */ +static const int MAX_DIFF = 2; + +/* width range to be checked for chirping */ +static const int MIN_CHIRP_PULSE_WIDTH = 20; +static const int MAX_CHIRP_PULSE_WIDTH = 110; + +struct ath9k_dfs_fft_20 { + u8 bin[28]; + u8 lower_bins[3]; +} __packed; +struct ath9k_dfs_fft_40 { + u8 bin[64]; + u8 lower_bins[3]; + u8 upper_bins[3]; +} __packed; + +static inline int fft_max_index(u8 *bins) +{ + return (bins[2] & 0xfc) >> 2; +} +static inline int fft_max_magnitude(u8 *bins) +{ + return (bins[0] & 0xc0) >> 6 | bins[1] << 2 | (bins[2] & 0x03) << 10; +} +static inline u8 fft_bitmap_weight(u8 *bins) +{ + return bins[0] & 0x3f; +} + +static int ath9k_get_max_index_ht40(struct ath9k_dfs_fft_40 *fft, + bool is_ctl, bool is_ext) +{ + const int DFS_UPPER_BIN_OFFSET = 64; + /* if detected radar on both channels, select the significant one */ + if (is_ctl && is_ext) { + /* first check wether channels have 'strong' bins */ + is_ctl = fft_bitmap_weight(fft->lower_bins) != 0; + is_ext = fft_bitmap_weight(fft->upper_bins) != 0; + + /* if still unclear, take higher magnitude */ + if (is_ctl && is_ext) { + int mag_lower = fft_max_magnitude(fft->lower_bins); + int mag_upper = fft_max_magnitude(fft->upper_bins); + if (mag_upper > mag_lower) + is_ctl = false; + else + is_ext = false; + } + } + if (is_ctl) + return fft_max_index(fft->lower_bins); + return fft_max_index(fft->upper_bins) + DFS_UPPER_BIN_OFFSET; +} +static bool ath9k_check_chirping(struct ath_softc *sc, u8 *data, + int datalen, bool is_ctl, bool is_ext) +{ + int i; + int max_bin[FFT_NUM_SAMPLES]; + struct ath_hw *ah = sc->sc_ah; + struct ath_common *common = ath9k_hw_common(ah); + int prev_delta; + + if (IS_CHAN_HT40(ah->curchan)) { + struct ath9k_dfs_fft_40 *fft = (struct ath9k_dfs_fft_40 *) data; + int num_fft_packets = datalen / sizeof(*fft); + if (num_fft_packets == 0) + return false; + + ath_dbg(common, DFS, "HT40: datalen=%d, num_fft_packets=%d\n", + datalen, num_fft_packets); + if (num_fft_packets < (FFT_NUM_SAMPLES)) { + ath_dbg(common, DFS, "not enough packets for chirp\n"); + return false; + } + /* HW sometimes adds 2 garbage bytes in front of FFT samples */ + if ((datalen % sizeof(*fft)) == 2) { + fft = (struct ath9k_dfs_fft_40 *) (data + 2); + ath_dbg(common, DFS, "fixing datalen by 2\n"); + } + if (IS_CHAN_HT40MINUS(ah->curchan)) { + int temp = is_ctl; + is_ctl = is_ext; + is_ext = temp; + } + for (i = 0; i < FFT_NUM_SAMPLES; i++) + max_bin[i] = ath9k_get_max_index_ht40(fft + i, is_ctl, + is_ext); + } else { + struct ath9k_dfs_fft_20 *fft = (struct ath9k_dfs_fft_20 *) data; + int num_fft_packets = datalen / sizeof(*fft); + if (num_fft_packets == 0) + return false; + ath_dbg(common, DFS, "HT20: datalen=%d, num_fft_packets=%d\n", + datalen, num_fft_packets); + if (num_fft_packets < (FFT_NUM_SAMPLES)) { + ath_dbg(common, DFS, "not enough packets for chirp\n"); + return false; + } + /* in ht20, this is a 6-bit signed number => shift it to 0 */ + for (i = 0; i < FFT_NUM_SAMPLES; i++) + max_bin[i] = fft_max_index(fft[i].lower_bins) ^ 0x20; + } + ath_dbg(common, DFS, "bin_max = [%d, %d, %d, %d]\n", + max_bin[0], max_bin[1], max_bin[2], max_bin[3]); + + /* Check for chirp attributes within specs + * a) delta of adjacent max_bins is within range + * b) delta of adjacent deltas are within tolerance + */ + prev_delta = 0; + for (i = 0; i < NUM_DIFFS; i++) { + int ddelta = -1; + int delta = max_bin[i + 1] - max_bin[i]; + + /* ensure gradient is within valid range */ + if (abs(delta) < BIN_DELTA_MIN || abs(delta) > BIN_DELTA_MAX) { + ath_dbg(common, DFS, "CHIRP: invalid delta %d " + "in sample %d\n", delta, i); + return false; + } + if (i == 0) + goto done; + ddelta = delta - prev_delta; + if (abs(ddelta) > MAX_DIFF) { + ath_dbg(common, DFS, "CHIRP: ddelta %d too high\n", + ddelta); + return false; + } +done: + ath_dbg(common, DFS, "CHIRP - %d: delta=%d, ddelta=%d\n", + i, delta, ddelta); + prev_delta = delta; + } + return true; +} +/**** end: CHIRP **************************************************************/ + /* convert pulse duration to usecs, considering clock mode */ static u32 dur_to_usecs(struct ath_hw *ah, u32 dur) { @@ -113,12 +264,6 @@ ath9k_postprocess_radar_event(struct ath_softc *sc, return false; } - /* - * TODO: check chirping pulses - * checks for chirping are dependent on the DFS regulatory domain - * used, which is yet TBD - */ - /* convert duration to usecs */ pe->width = dur_to_usecs(sc->sc_ah, dur); pe->rssi = rssi; @@ -190,6 +335,16 @@ void ath9k_dfs_process_phyerr(struct ath_softc *sc, void *data, if (!ath9k_postprocess_radar_event(sc, &ard, &pe)) return; + if (pe.width > MIN_CHIRP_PULSE_WIDTH && + pe.width < MAX_CHIRP_PULSE_WIDTH) { + bool is_ctl = !!(ard.pulse_bw_info & PRI_CH_RADAR_FOUND); + bool is_ext = !!(ard.pulse_bw_info & EXT_CH_RADAR_FOUND); + int clen = datalen - 3; + pe.chirp = ath9k_check_chirping(sc, data, clen, is_ctl, is_ext); + } else { + pe.chirp = false; + } + ath_dbg(common, DFS, "ath9k_dfs_process_phyerr: type=%d, freq=%d, ts=%llu, " "width=%d, rssi=%d, delta_ts=%llu\n", @@ -198,7 +353,8 @@ void ath9k_dfs_process_phyerr(struct ath_softc *sc, void *data, sc->dfs_prev_pulse_ts = pe.ts; if (ard.pulse_bw_info & PRI_CH_RADAR_FOUND) ath9k_dfs_process_radar_pulse(sc, &pe); - if (ard.pulse_bw_info & EXT_CH_RADAR_FOUND) { + if (IS_CHAN_HT40(ah->curchan) && + ard.pulse_bw_info & EXT_CH_RADAR_FOUND) { pe.freq += IS_CHAN_HT40PLUS(ah->curchan) ? 20 : -20; ath9k_dfs_process_radar_pulse(sc, &pe); } |