Change INTERPOLATE_RATE macro to a lookup-table instead for the sake of
readability.
Signed-off-by: Matthew Wang <matthewmwang@xxxxxxxxxxxx>
---
wpa_supplicant/scan.c | 127 ++++++++++++++++++++++++++----------------
1 file changed, 79 insertions(+), 48 deletions(-)
diff --git a/wpa_supplicant/scan.c b/wpa_supplicant/scan.c
index b47573094..85513779f 100644
--- a/wpa_supplicant/scan.c
+++ b/wpa_supplicant/scan.c
@@ -2186,6 +2186,63 @@ void scan_snr(struct wpa_scan_res *res)
}
}
+/* Minimum SNR required to achieve a certain bitrate. */
+struct minsnr_bitrate_entry {
+ int minsnr;
+ unsigned int bitrate; /* in Mbps */
+};
+
+
+/* VHT needs to be enabled in order to achieve MCS8 and MCS9 rates. */
+static const int vht_mcs = 8;
+
+
+static struct minsnr_bitrate_entry vht20_table[] = {
+ {0, 0},
+ {2, 6500}, /* HT20 MCS0 */
+ {5, 13000}, /* HT20 MCS1 */
+ {9, 19500}, /* HT20 MCS2 */
+ {11, 26000}, /* HT20 MCS3 */
+ {15, 39000}, /* HT20 MCS4 */
+ {18, 52000}, /* HT20 MCS5 */
+ {20, 58500}, /* HT20 MCS6 */
+ {25, 65000}, /* HT20 MCS7 */
+ {29, 78000}, /* VHT20 MCS8 */
+ {-1, 78000} /* SNR > 29 */
+};
+
+
+static struct minsnr_bitrate_entry vht40_table[] = {
+ {0, 0},
+ {5, 13500}, /* HT40 MCS0 */
+ {8, 27000}, /* HT40 MCS1 */
+ {12, 40500}, /* HT40 MCS2 */
+ {14, 54000}, /* HT40 MCS3 */
+ {18, 81000}, /* HT40 MCS4 */
+ {21, 108000}, /* HT40 MCS5 */
+ {23, 121500}, /* HT40 MCS6 */
+ {28, 135000}, /* HT40 MCS7 */
+ {32, 162000}, /* VHT40 MCS8 */
+ {34, 180000}, /* VHT40 MCS9 */
+ {-1, 180000} /* SNR > 34 */
+};
+
+
+static struct minsnr_bitrate_entry vht80_table[] = {
+ {0, 0},
+ {8, 29300}, /* VHT80 MCS0 */
+ {11, 58500}, /* VHT80 MCS1 */
+ {15, 87800}, /* VHT80 MCS2 */
+ {17, 117000}, /* VHT80 MCS3 */
+ {21, 175500}, /* VHT80 MCS4 */
+ {24, 234000}, /* VHT80 MCS5 */
+ {26, 263300}, /* VHT80 MCS6 */
+ {31, 292500}, /* VHT80 MCS7 */
+ {35, 351000}, /* VHT80 MCS8 */
+ {37, 390000}, /* VHT80 MCS9 */
+ {-1, 390000} /* SNR > 37 */
+};
+
static unsigned int interpolate_rate(int snr, int snr0, int snr1,
int rate0, int rate1)
@@ -2194,67 +2251,41 @@ static unsigned int interpolate_rate(int snr, int snr0, int snr1,
}
-#define INTERPOLATE_RATE(snr0, snr1, rate0, rate1) \
- if (snr < (snr1)) \
- return interpolate_rate(snr, (snr0), (snr1), (rate0), (rate1))
+static unsigned int max_rate(struct minsnr_bitrate_entry table[],
+ int snr, int vht)
+{
+ struct minsnr_bitrate_entry *prev, *entry = table;
+
+ while ((entry->minsnr != -1) &&
+ (snr >= entry->minsnr) &&
+ (vht || entry - table <= vht_mcs))
+ entry++;
+ if (entry == table)
+ return entry->bitrate;
+ prev = entry - 1;
+ if (entry->minsnr == -1 || (!vht && entry - table > vht_mcs))
+ return prev->bitrate;
+ return interpolate_rate(snr, prev->minsnr, entry->minsnr, prev->bitrate,
+ entry->bitrate);
+}
+
static unsigned int max_ht20_rate(int snr, int vht)
{
- if (snr < 0)
- return 0;
- INTERPOLATE_RATE(0, 2, 0, 6500); /* HT20 MCS0 */
- INTERPOLATE_RATE(2, 5, 6500, 13000); /* HT20 MCS1 */
- INTERPOLATE_RATE(5, 9, 13000, 19500); /* HT20 MCS2 */
- INTERPOLATE_RATE(9, 11, 19500, 26000); /* HT20 MCS3 */
- INTERPOLATE_RATE(11, 15, 26000, 39000); /* HT20 MCS4 */
- INTERPOLATE_RATE(15, 18, 39000, 52000); /* HT20 MCS5 */
- INTERPOLATE_RATE(18, 20, 52000, 58500); /* HT20 MCS6 */
- INTERPOLATE_RATE(20, 25, 58500, 65000); /* HT20 MCS7 */
- if (!vht)
- return 65000;
- INTERPOLATE_RATE(25, 29, 65000, 78000); /* VHT20 MCS8 */
- return 78000;
+ return max_rate(vht20_table, snr, vht);
}
static unsigned int max_ht40_rate(int snr, int vht)
{
- if (snr < 0)
- return 0;
- INTERPOLATE_RATE(0, 5, 0, 13500); /* HT40 MCS0 */
- INTERPOLATE_RATE(5, 8, 13500, 27000); /* HT40 MCS1 */
- INTERPOLATE_RATE(8, 12, 27000, 40500); /* HT40 MCS2 */
- INTERPOLATE_RATE(12, 14, 40500, 54000); /* HT40 MCS3 */
- INTERPOLATE_RATE(14, 18, 54000, 81000); /* HT40 MCS4 */
- INTERPOLATE_RATE(18, 21, 81000, 108000); /* HT40 MCS5 */
- INTERPOLATE_RATE(21, 23, 108000, 121500); /* HT40 MCS6 */
- INTERPOLATE_RATE(23, 28, 121500, 135000); /* HT40 MCS7 */
- if (!vht)
- return 135000;
- INTERPOLATE_RATE(28, 32, 135000, 162000); /* VHT40 MCS8 */
- INTERPOLATE_RATE(32, 34, 162000, 180000); /* VHT40 MCS9 */
- return 180000;
+ return max_rate(vht40_table, snr, vht);
}
static unsigned int max_vht80_rate(int snr)
{
- if (snr < 0)
- return 0;
- INTERPOLATE_RATE(0, 8, 0, 29300); /* VHT80 MCS0 */
- INTERPOLATE_RATE(8, 11, 29300, 58500); /* VHT80 MCS1 */
- INTERPOLATE_RATE(11, 15, 58500, 87800); /* VHT80 MCS2 */
- INTERPOLATE_RATE(15, 17, 87800, 117000); /* VHT80 MCS3 */
- INTERPOLATE_RATE(17, 21, 117000, 175500); /* VHT80 MCS4 */
- INTERPOLATE_RATE(21, 24, 175500, 234000); /* VHT80 MCS5 */
- INTERPOLATE_RATE(24, 26, 234000, 263300); /* VHT80 MCS6 */
- INTERPOLATE_RATE(26, 31, 263300, 292500); /* VHT80 MCS7 */
- INTERPOLATE_RATE(31, 35, 292500, 351000); /* VHT80 MCS8 */
- INTERPOLATE_RATE(35, 37, 351000, 390000); /* VHT80 MCS9 */
- return 390000;
-}
-
-#undef INTERPOLATE_RATE
+ return max_rate(vht80_table, snr, 1);
+}
unsigned int wpas_get_est_tpt(const struct wpa_supplicant *wpa_s,
--
2.27.0.rc0.183.gde8f92d652-goog
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