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https://git.kernel.org/pub/scm/network/wireless/iwd.git
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band: Move ht/vht data rate calculation out of ie.c
This commit is contained in:
Denis Kenzior
parent
e41bee377d
commit
842a70a307
89
src/band.c
89
src/band.c
@ -20,9 +20,98 @@
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*
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*/
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#include <stdbool.h>
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#include <stdint.h>
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#include <ell/ell.h>
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#include "band.h"
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void band_free(struct band *band)
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{
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l_free(band);
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}
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/*
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* Base RSSI values for 20MHz (both HT and VHT) channel. These values can be
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* used to calculate the minimum RSSI values for all other channel widths. HT
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* MCS indexes are grouped into ranges of 8 (per spatial stream) where VHT are
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* grouped in chunks of 10. This just means HT will not use the last two
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* index's of this array.
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*/
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static const int32_t ht_vht_base_rssi[] = {
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-82, -79, -77, -74, -70, -66, -65, -64, -59, -57
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};
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/*
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* Data Rate for HT/VHT is obtained according to this formula:
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* Nsd * Nbpscs * R * Nss / (Tdft + Tgi)
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*
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* Where Nsd is [52, 108, 234, 468] for 20/40/80/160 Mhz respectively
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* Nbpscs is [1, 2, 4, 6, 8] for BPSK/QPSK/16QAM/64QAM/256QAM
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* R is [1/2, 2/3, 3/4, 5/6] depending on the MCS index
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* Nss is the number of spatial streams
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* Tdft = 3.2 us
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* Tgi = Long/Short GI of 0.8/0.4 us
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*
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* Short GI rate can be easily obtained by multiplying by (10 / 9)
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*
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* The table was pre-computed using the following python snippet:
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* rfactors = [ 1/2, 1/2, 3/4, 1/2, 3/4, 2/3, 3/4, 5/6, 3/4, 5/6 ]
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* nbpscs = [1, 2, 2, 4, 4, 6, 6, 6, 8, 8 ]
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* nsds = [52, 108, 234, 468]
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*
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* for nsd in nsds:
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* rates = []
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* for i in xrange(0, 10):
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* data_rate = (nsd * rfactors[i] * nbpscs[i]) / 0.004
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* rates.append(int(data_rate) * 1000)
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* print('rates for nsd: ' + nsd + ': ' + rates)
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*/
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static const uint64_t ht_vht_rates[4][10] = {
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[OFDM_CHANNEL_WIDTH_20MHZ] = {
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6500000ULL, 13000000ULL, 19500000ULL, 26000000ULL,
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39000000ULL, 52000000ULL, 58500000ULL, 65000000ULL,
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78000000ULL, 86666000ULL },
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[OFDM_CHANNEL_WIDTH_40MHZ] = {
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13500000ULL, 27000000ULL, 40500000ULL, 54000000ULL,
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81000000ULL, 108000000ULL, 121500000ULL, 135000000ULL,
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162000000ULL, 180000000ULL, },
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[OFDM_CHANNEL_WIDTH_80MHZ] = {
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29250000ULL, 58500000ULL, 87750000ULL, 117000000ULL,
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175500000ULL, 234000000ULL, 263250000ULL, 292500000ULL,
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351000000ULL, 390000000ULL, },
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[OFDM_CHANNEL_WIDTH_160MHZ] = {
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58500000ULL, 117000000ULL, 175500000ULL, 234000000ULL,
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351000000ULL, 468000000ULL, 526500000ULL, 585000000ULL,
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702000000ULL, 780000000ULL,
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}
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};
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/*
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* Both HT and VHT rates are calculated in the same fashion. The only difference
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* is a relative MCS index is used for HT since, for each NSS, the formula
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* is the same with relative index's. This is why this is called with index % 8
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* for HT, but not VHT.
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*/
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bool band_ofdm_rate(uint8_t index, enum ofdm_channel_width width,
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int32_t rssi, uint8_t nss, bool sgi,
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uint64_t *data_rate)
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{
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uint64_t rate;
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int32_t width_adjust = width * 3;
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if (rssi < ht_vht_base_rssi[index] + width_adjust)
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return false;
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rate = ht_vht_rates[width][index];
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if (sgi)
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rate = rate / 9 * 10;
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rate *= nss;
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*data_rate = rate;
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return true;
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}
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11
src/band.h
11
src/band.h
@ -20,6 +20,13 @@
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*
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*/
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enum ofdm_channel_width {
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OFDM_CHANNEL_WIDTH_20MHZ = 0,
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OFDM_CHANNEL_WIDTH_40MHZ,
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OFDM_CHANNEL_WIDTH_80MHZ,
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OFDM_CHANNEL_WIDTH_160MHZ,
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};
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struct band {
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uint8_t vht_mcs_set[8];
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uint8_t vht_capabilities[4];
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@ -32,3 +39,7 @@ struct band {
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};
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void band_free(struct band *band);
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bool band_ofdm_rate(uint8_t index, enum ofdm_channel_width width,
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int32_t rssi, uint8_t nss, bool sgi,
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uint64_t *data_rate);
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119
src/ie.c
119
src/ie.c
@ -31,6 +31,7 @@
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#include "ell/useful.h"
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#include "src/util.h"
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#include "src/crypto.h"
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#include "src/band.h"
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#include "src/ie.h"
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const unsigned char ieee_oui[3] = { 0x00, 0x0f, 0xac };
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@ -1726,98 +1727,6 @@ static int ie_parse_supported_rates_from_data(const uint8_t *supp_rates_ie,
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return 0;
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}
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enum ht_vht_channel_width {
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HT_VHT_CHANNEL_WIDTH_20MHZ = 0,
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HT_VHT_CHANNEL_WIDTH_40MHZ,
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HT_VHT_CHANNEL_WIDTH_80MHZ,
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HT_VHT_CHANNEL_WIDTH_160MHZ,
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};
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/*
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* Base RSSI values for 20MHz (both HT and VHT) channel. These values can be
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* used to calculate the minimum RSSI values for all other channel widths. HT
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* MCS indexes are grouped into ranges of 8 (per spatial stream) where VHT are
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* grouped in chunks of 10. This just means HT will not use the last two
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* index's of this array.
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*/
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static const int32_t ht_vht_base_rssi[] = {
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-82, -79, -77, -74, -70, -66, -65, -64, -59, -57
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};
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/*
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* Data Rate for HT/VHT is obtained according to this formula:
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* Nsd * Nbpscs * R * Nss / (Tdft + Tgi)
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*
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* Where Nsd is [52, 108, 234, 468] for 20/40/80/160 Mhz respectively
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* Nbpscs is [1, 2, 4, 6, 8] for BPSK/QPSK/16QAM/64QAM/256QAM
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* R is [1/2, 2/3, 3/4, 5/6] depending on the MCS index
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* Nss is the number of spatial streams
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* Tdft = 3.2 us
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* Tgi = Long/Short GI of 0.8/0.4 us
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*
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* Short GI rate can be easily obtained by multiplying by (10 / 9)
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*
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* The table was pre-computed using the following python snippet:
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* rfactors = [ 1/2, 1/2, 3/4, 1/2, 3/4, 2/3, 3/4, 5/6, 3/4, 5/6 ]
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* nbpscs = [1, 2, 2, 4, 4, 6, 6, 6, 8, 8 ]
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* nsds = [52, 108, 234, 468]
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*
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* for nsd in nsds:
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* rates = []
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* for i in xrange(0, 10):
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* data_rate = (nsd * rfactors[i] * nbpscs[i]) / 0.004
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* rates.append(int(data_rate) * 1000)
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* print('rates for nsd: ' + nsd + ': ' + rates)
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*/
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static const uint64_t ht_vht_rates[4][10] = {
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[HT_VHT_CHANNEL_WIDTH_20MHZ] = {
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6500000ULL, 13000000ULL, 19500000ULL, 26000000ULL,
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39000000ULL, 52000000ULL, 58500000ULL, 65000000ULL,
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78000000ULL, 86666000ULL },
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[HT_VHT_CHANNEL_WIDTH_40MHZ] = {
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13500000ULL, 27000000ULL, 40500000ULL, 54000000ULL,
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81000000ULL, 108000000ULL, 121500000ULL, 135000000ULL,
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162000000ULL, 180000000ULL, },
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[HT_VHT_CHANNEL_WIDTH_80MHZ] = {
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29250000ULL, 58500000ULL, 87750000ULL, 117000000ULL,
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175500000ULL, 234000000ULL, 263250000ULL, 292500000ULL,
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351000000ULL, 390000000ULL, },
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[HT_VHT_CHANNEL_WIDTH_160MHZ] = {
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58500000ULL, 117000000ULL, 175500000ULL, 234000000ULL,
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351000000ULL, 468000000ULL, 526500000ULL, 585000000ULL,
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702000000ULL, 780000000ULL,
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}
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};
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/*
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* Both HT and VHT rates are calculated in the same fashion. The only difference
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* is a relative MCS index is used for HT since, for each NSS, the formula
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* is the same with relative index's. This is why this is called with index % 8
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* for HT, but not VHT.
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*/
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static bool calculate_ht_vht_data_rate(uint8_t index,
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enum ht_vht_channel_width width,
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int32_t rssi, uint8_t nss, bool sgi,
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uint64_t *data_rate)
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{
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uint64_t rate;
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int32_t width_adjust = width * 3;
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if (rssi < ht_vht_base_rssi[index] + width_adjust)
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return false;
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rate = ht_vht_rates[width][index];
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if (sgi)
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rate = rate / 9 * 10;
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rate *= nss;
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*data_rate = rate;
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return true;
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}
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static int ie_parse_ht_capability(struct ie_tlv_iter *iter, int32_t rssi,
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uint64_t *data_rate)
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{
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@ -1867,19 +1776,15 @@ static int ie_parse_ht_capability(struct ie_tlv_iter *iter, int32_t rssi,
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if (!support_40mhz)
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goto check_20;
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if (calculate_ht_vht_data_rate(i % 8,
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HT_VHT_CHANNEL_WIDTH_40MHZ,
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rssi, (i / 8) + 1,
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short_gi_40mhz, &drate)) {
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if (band_ofdm_rate(i % 8, OFDM_CHANNEL_WIDTH_40MHZ,
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rssi, (i / 8) + 1, short_gi_40mhz, &drate)) {
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*data_rate = drate;
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return 0;
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}
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check_20:
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if (!calculate_ht_vht_data_rate(i % 8,
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HT_VHT_CHANNEL_WIDTH_20MHZ,
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rssi, (i / 8) + 1,
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short_gi_20mhz, &drate))
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if (!band_ofdm_rate(i % 8, OFDM_CHANNEL_WIDTH_20MHZ,
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rssi, (i / 8) + 1, short_gi_20mhz, &drate))
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continue;
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if (!support_40mhz) {
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@ -2046,31 +1951,31 @@ static int ie_parse_vht_capability(struct ie_tlv_iter *vht_iter,
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* on the channel width for this iteration.
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*/
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switch (width) {
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case HT_VHT_CHANNEL_WIDTH_20MHZ:
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case OFDM_CHANNEL_WIDTH_20MHZ:
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sgi = short_gi_20mhz;
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break;
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case HT_VHT_CHANNEL_WIDTH_40MHZ:
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case OFDM_CHANNEL_WIDTH_40MHZ:
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sgi = short_gi_40mhz;
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break;
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case HT_VHT_CHANNEL_WIDTH_80MHZ:
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case OFDM_CHANNEL_WIDTH_80MHZ:
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sgi = short_gi_80mhz;
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break;
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case HT_VHT_CHANNEL_WIDTH_160MHZ:
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case OFDM_CHANNEL_WIDTH_160MHZ:
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sgi = short_gi_160mhz;
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break;
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}
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for (nss = minsize(rx_nss, tx_nss); nss > 0; nss--) {
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/* NSS > 4 does not apply to 20/40MHz */
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if (width <= HT_VHT_CHANNEL_WIDTH_40MHZ && nss > 4)
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if (width <= OFDM_CHANNEL_WIDTH_40MHZ && nss > 4)
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continue;
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for (mcs = minsize(max_rx_mcs, max_tx_mcs);
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mcs >= 0; mcs--) {
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uint64_t drate;
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if (!calculate_ht_vht_data_rate(mcs, width,
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rssi, nss, sgi, &drate))
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if (!band_ofdm_rate(mcs, width, rssi,
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nss, sgi, &drate))
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continue;
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if (drate > highest_rate)
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