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 */
--
1.9.1
--
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