After further discussion with Nick, we better leave spectral as is.
Please ignore / drop this one.
On 06/18/2015 01:17 PM, Zefir Kurtisi wrote:
> The max_index value provided in the spectral data set
> has to be interpreted differently for HT20 and HT40.
> In HT40, the value is given as unsigned index and
> shall be taken as is, while in HT20 it is a signed
> value around bin index 28 and needs to be converted
> to an unsigned index.
>
> This patch simplifies the previous correction and
> prepares the related functions to be shared with
> the DFS module.
>
> Signed-off-by: Zefir Kurtisi <zefir.kurtisi@xxxxxxxxxxx>
> ---
>
> v2: fix conversion offset as reported by Nick Kossifidis
>
> drivers/net/wireless/ath/ath9k/common-spectral.c | 20 ++++++-------
> drivers/net/wireless/ath/ath9k/common-spectral.h | 36 +++++++-----------------
> 2 files changed, 18 insertions(+), 38 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/ath9k/common-spectral.c b/drivers/net/wireless/ath/ath9k/common-spectral.c
> index a876271..175193d 100644
> --- a/drivers/net/wireless/ath/ath9k/common-spectral.c
> +++ b/drivers/net/wireless/ath/ath9k/common-spectral.c
> @@ -59,8 +59,8 @@ ath_cmn_max_idx_verify_ht20_fft(u8 *sample_end, int bytes_read)
>
> sample = sample_end - SPECTRAL_HT20_SAMPLE_LEN + 1;
>
> - max_index = spectral_max_index(mag_info->all_bins,
> - SPECTRAL_HT20_NUM_BINS);
> + /* in ht20, this is a 6-bit signed number => shift it to 0 */
> + max_index = (spectral_max_index(mag_info->all_bins) ^ 0x20) - 4;
> max_magnitude = spectral_max_magnitude(mag_info->all_bins);
>
> max_exp = mag_info->max_exp & 0xf;
> @@ -100,12 +100,10 @@ ath_cmn_max_idx_verify_ht20_40_fft(u8 *sample_end, int bytes_read)
> sample = sample_end - SPECTRAL_HT20_40_SAMPLE_LEN + 1;
>
> lower_mag = spectral_max_magnitude(mag_info->lower_bins);
> - lower_max_index = spectral_max_index(mag_info->lower_bins,
> - SPECTRAL_HT20_40_NUM_BINS);
> + lower_max_index = spectral_max_index(mag_info->lower_bins);
>
> upper_mag = spectral_max_magnitude(mag_info->upper_bins);
> - upper_max_index = spectral_max_index(mag_info->upper_bins,
> - SPECTRAL_HT20_40_NUM_BINS);
> + upper_max_index = spectral_max_index(mag_info->upper_bins);
>
> max_exp = mag_info->max_exp & 0xf;
>
> @@ -169,8 +167,8 @@ ath_cmn_process_ht20_fft(struct ath_rx_status *rs,
> magnitude = spectral_max_magnitude(mag_info->all_bins);
> fft_sample_20.max_magnitude = __cpu_to_be16(magnitude);
>
> - max_index = spectral_max_index(mag_info->all_bins,
> - SPECTRAL_HT20_NUM_BINS);
> + /* in ht20, this is a 6-bit signed number => shift it to 0 */
> + max_index = (spectral_max_index(mag_info->all_bins) ^ 0x20) - 4;
> fft_sample_20.max_index = max_index;
>
> bitmap_w = spectral_bitmap_weight(mag_info->all_bins);
> @@ -302,12 +300,10 @@ ath_cmn_process_ht20_40_fft(struct ath_rx_status *rs,
> 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(mag_info->lower_bins,
> - SPECTRAL_HT20_40_NUM_BINS);
> + lower_max_index = spectral_max_index(mag_info->lower_bins);
> fft_sample_40.lower_max_index = lower_max_index;
>
> - upper_max_index = spectral_max_index(mag_info->upper_bins,
> - SPECTRAL_HT20_40_NUM_BINS);
> + upper_max_index = spectral_max_index(mag_info->upper_bins);
> fft_sample_40.upper_max_index = upper_max_index;
>
> lower_bitmap_w = spectral_bitmap_weight(mag_info->lower_bins);
> diff --git a/drivers/net/wireless/ath/ath9k/common-spectral.h b/drivers/net/wireless/ath/ath9k/common-spectral.h
> index 998743b..7540835 100644
> --- a/drivers/net/wireless/ath/ath9k/common-spectral.h
> +++ b/drivers/net/wireless/ath/ath9k/common-spectral.h
> @@ -116,33 +116,17 @@ static inline u16 spectral_max_magnitude(u8 *bins)
> (bins[2] & 0x03) << 10;
> }
>
> -/* return the max magnitude from the all/upper/lower bins */
> -static inline u8 spectral_max_index(u8 *bins, int num_bins)
> +/* return the max index from the all/upper/lower bins
> + *
> + * in HT20: 6-bit signed number of range -28 to +27
> + * in HT40: 6-bit unsigned number of range 0 to +63
> + * (upper sub-channel index 0 is DC)
> + *
> + * Correct interpretation of the value has to be done at caller
> + */
> +static inline u8 spectral_max_index(u8 *bins)
> {
> - s8 m = (bins[2] & 0xfc) >> 2;
> - u8 zero_idx = num_bins / 2;
> -
> - /* It's a 5 bit signed int, remove its sign and use one's
> - * complement interpretation to add the sign back to the 8
> - * bit int
> - */
> - if (m & 0x20) {
> - m &= ~0x20;
> - m |= 0xe0;
> - }
> -
> - /* Bring the zero point to the beginning
> - * instead of the middle so that we can use
> - * it for array lookup and that we don't deal
> - * with negative values later
> - */
> - m += zero_idx;
> -
> - /* Sanity check to make sure index is within bounds */
> - if (m < 0 || m > num_bins - 1)
> - m = 0;
> -
> - return m;
> + return (bins[2] & 0xfc) >> 2;
> }
>
> /* return the bitmap weight from the all/upper/lower bins */
>
--
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