[PATCH v2] wifi: mt76: fix backoff fields and max_power calculation
Ryder Lee
ryder.lee at mediatek.com
Tue Jan 27 15:55:57 PST 2026
From: Allen Ye <allen.ye at mediatek.com>
The maximum power value may exist in either the data or backoff field.
Previously, backoff power limits were not considered in txpower reporting.
This patch ensures mt76 also considers backoff values in the SKU table.
For connac2 devices,
- paths-ru = RU26, RU52, RU106, BW20, BW40, BW80, BW160
- paths-ru-bf = RU26, RU52, RU106, BW20, BW40, BW80, BW160
Only the first three entries use 1T1S and do not need index adjustment;
the remaining four require index offset.
Fixes: b05ab4be9fd7 ("wifi: mt76: mt7915: add bf backoff limit table support")
Signed-off-by: Allen Ye <allen.ye at mediatek.com>
Signed-off-by: Ryder Lee <ryder.lee at mediatek.com>
---
v1:
- Add "wifi:" prefix to the subject.
v2:
- Fix checkpatch errors.
- Remove unnecessary style changes.
- Add explanation for connac2 index adjustment.
---
drivers/net/wireless/mediatek/mt76/eeprom.c | 180 +++++++++++++-------
drivers/net/wireless/mediatek/mt76/mt76.h | 1 -
2 files changed, 122 insertions(+), 59 deletions(-)
diff --git a/drivers/net/wireless/mediatek/mt76/eeprom.c b/drivers/net/wireless/mediatek/mt76/eeprom.c
index 573400d57..6ca0274b4 100644
--- a/drivers/net/wireless/mediatek/mt76/eeprom.c
+++ b/drivers/net/wireless/mediatek/mt76/eeprom.c
@@ -9,6 +9,13 @@
#include <linux/nvmem-consumer.h>
#include <linux/etherdevice.h>
#include "mt76.h"
+#include "mt76_connac.h"
+
+enum mt76_sku_type {
+ MT76_SKU_RATE,
+ MT76_SKU_BACKOFF,
+ MT76_SKU_BACKOFF_BF_OFFSET,
+};
static int mt76_get_of_eeprom_data(struct mt76_dev *dev, void *eep, int len)
{
@@ -292,7 +299,6 @@ mt76_find_channel_node(struct device_node *np, struct ieee80211_channel *chan)
}
EXPORT_SYMBOL_GPL(mt76_find_channel_node);
-
static s8
mt76_get_txs_delta(struct device_node *np, u8 nss)
{
@@ -306,9 +312,24 @@ mt76_get_txs_delta(struct device_node *np, u8 nss)
return be32_to_cpu(val[nss - 1]);
}
+static inline u8 mt76_backoff_n_chains(struct mt76_dev *dev, u8 idx)
+{
+ /* 0:1T1ss, 1:2T1ss, ..., 14:5T5ss */
+ static const u8 connac3_table[] = {
+ 1, 2, 3, 4, 5, 2, 3, 4, 5, 3, 4, 5, 4, 5, 5};
+ static const u8 connac2_table[] = {
+ 1, 2, 3, 4, 2, 3, 4, 3, 4, 4, 0, 0, 0, 0, 0};
+
+ if (idx < 0 || idx >= ARRAY_SIZE(connac3_table))
+ return 0;
+
+ return is_mt799x(dev) ? connac3_table[idx] : connac2_table[idx];
+}
+
static void
-mt76_apply_array_limit(s8 *pwr, size_t pwr_len, const s8 *data,
- s8 target_power, s8 nss_delta, s8 *max_power)
+mt76_apply_array_limit(struct mt76_dev *dev, s8 *pwr, size_t pwr_len,
+ const s8 *data, s8 target_power, s8 nss_delta,
+ s8 *max_power, int n_chains, enum mt76_sku_type type)
{
int i;
@@ -316,18 +337,51 @@ mt76_apply_array_limit(s8 *pwr, size_t pwr_len, const s8 *data,
return;
for (i = 0; i < pwr_len; i++) {
- pwr[i] = min_t(s8, target_power, data[i] + nss_delta);
+ u8 backoff_chain_idx = i;
+ int backoff_n_chains;
+ s8 backoff_delta;
+ s8 delta;
+
+ switch (type) {
+ case MT76_SKU_RATE:
+ delta = 0;
+ backoff_delta = 0;
+ backoff_n_chains = 0;
+ break;
+ case MT76_SKU_BACKOFF:
+ backoff_chain_idx += 1;
+ fallthrough;
+ case MT76_SKU_BACKOFF_BF_OFFSET:
+ delta = mt76_tx_power_path_delta(n_chains);
+ backoff_n_chains = mt76_backoff_n_chains(dev, backoff_chain_idx);
+ backoff_delta = mt76_tx_power_path_delta(backoff_n_chains);
+ break;
+ default:
+ return;
+ }
+
+ pwr[i] = min_t(s8, target_power + delta - backoff_delta, data[i] + nss_delta);
+
+ /* used for padding, doesn't need to be considered */
+ if (data[i] >= S8_MAX - 1)
+ continue;
+
+ /* only consider backoff value for the configured chain number */
+ if (type != MT76_SKU_RATE && n_chains != backoff_n_chains)
+ continue;
+
*max_power = max(*max_power, pwr[i]);
}
}
static void
-mt76_apply_multi_array_limit(s8 *pwr, size_t pwr_len, s8 pwr_num,
- const s8 *data, size_t len, s8 target_power,
- s8 nss_delta)
+mt76_apply_multi_array_limit(struct mt76_dev *dev, s8 *pwr, size_t pwr_len,
+ s8 pwr_num, const s8 *data, size_t len,
+ s8 target_power, s8 nss_delta, s8 *max_power,
+ int n_chains, enum mt76_sku_type type)
{
+ static const int connac2_backoff_ru_idx = 2;
int i, cur;
- s8 max_power = -128;
if (!data)
return;
@@ -337,8 +391,19 @@ mt76_apply_multi_array_limit(s8 *pwr, size_t pwr_len, s8 pwr_num,
if (len < pwr_len + 1)
break;
- mt76_apply_array_limit(pwr + pwr_len * i, pwr_len, data + 1,
- target_power, nss_delta, &max_power);
+ /* For connac2 devices,
+ * - paths-ru = RU26, RU52, RU106, BW20, BW40, BW80, BW160
+ * - paths-ru-bf = RU26, RU52, RU106, BW20, BW40, BW80, BW160
+ * Only the first three entries use 1T1ss and do not need index
+ * adjustment; the remaining four require index offset.
+ */
+ if (!is_mt799x(dev) && type == MT76_SKU_BACKOFF &&
+ i > connac2_backoff_ru_idx)
+ type = MT76_SKU_BACKOFF_BF_OFFSET;
+
+ mt76_apply_array_limit(dev, pwr + pwr_len * i, pwr_len, data + 1,
+ target_power, nss_delta, max_power,
+ n_chains, type);
if (--cur > 0)
continue;
@@ -360,18 +425,11 @@ s8 mt76_get_rate_power_limits(struct mt76_phy *phy,
struct device_node *np;
const s8 *val;
char name[16];
- u32 mcs_rates = dev->drv->mcs_rates;
- u32 ru_rates = ARRAY_SIZE(dest->ru[0]);
char band;
size_t len;
- s8 max_power = 0;
- s8 max_power_backoff = -127;
+ s8 max_power = -127;
s8 txs_delta;
int n_chains = hweight16(phy->chainmask);
- s8 target_power_combine = target_power + mt76_tx_power_path_delta(n_chains);
-
- if (!mcs_rates)
- mcs_rates = 10;
memset(dest, target_power, sizeof(*dest) - sizeof(dest->path));
memset(&dest->path, 0, sizeof(dest->path));
@@ -409,46 +467,52 @@ s8 mt76_get_rate_power_limits(struct mt76_phy *phy,
txs_delta = mt76_get_txs_delta(np, hweight16(phy->chainmask));
val = mt76_get_of_array_s8(np, "rates-cck", &len, ARRAY_SIZE(dest->cck));
- mt76_apply_array_limit(dest->cck, ARRAY_SIZE(dest->cck), val,
- target_power, txs_delta, &max_power);
-
- val = mt76_get_of_array_s8(np, "rates-ofdm",
- &len, ARRAY_SIZE(dest->ofdm));
- mt76_apply_array_limit(dest->ofdm, ARRAY_SIZE(dest->ofdm), val,
- target_power, txs_delta, &max_power);
-
- val = mt76_get_of_array_s8(np, "rates-mcs", &len, mcs_rates + 1);
- mt76_apply_multi_array_limit(dest->mcs[0], ARRAY_SIZE(dest->mcs[0]),
- ARRAY_SIZE(dest->mcs), val, len,
- target_power, txs_delta);
-
- val = mt76_get_of_array_s8(np, "rates-ru", &len, ru_rates + 1);
- mt76_apply_multi_array_limit(dest->ru[0], ARRAY_SIZE(dest->ru[0]),
- ARRAY_SIZE(dest->ru), val, len,
- target_power, txs_delta);
-
- max_power_backoff = max_power;
- val = mt76_get_of_array_s8(np, "paths-cck", &len, ARRAY_SIZE(dest->path.cck));
- mt76_apply_array_limit(dest->path.cck, ARRAY_SIZE(dest->path.cck), val,
- target_power_combine, txs_delta, &max_power_backoff);
-
- val = mt76_get_of_array_s8(np, "paths-ofdm", &len, ARRAY_SIZE(dest->path.ofdm));
- mt76_apply_array_limit(dest->path.ofdm, ARRAY_SIZE(dest->path.ofdm), val,
- target_power_combine, txs_delta, &max_power_backoff);
-
- val = mt76_get_of_array_s8(np, "paths-ofdm-bf", &len, ARRAY_SIZE(dest->path.ofdm_bf));
- mt76_apply_array_limit(dest->path.ofdm_bf, ARRAY_SIZE(dest->path.ofdm_bf), val,
- target_power_combine, txs_delta, &max_power_backoff);
-
- val = mt76_get_of_array_s8(np, "paths-ru", &len, ARRAY_SIZE(dest->path.ru[0]) + 1);
- mt76_apply_multi_array_limit(dest->path.ru[0], ARRAY_SIZE(dest->path.ru[0]),
- ARRAY_SIZE(dest->path.ru), val, len,
- target_power_combine, txs_delta);
-
- val = mt76_get_of_array_s8(np, "paths-ru-bf", &len, ARRAY_SIZE(dest->path.ru_bf[0]) + 1);
- mt76_apply_multi_array_limit(dest->path.ru_bf[0], ARRAY_SIZE(dest->path.ru_bf[0]),
- ARRAY_SIZE(dest->path.ru_bf), val, len,
- target_power_combine, txs_delta);
+ mt76_apply_array_limit(dev, dest->cck, ARRAY_SIZE(dest->cck), val,
+ target_power, txs_delta, &max_power, n_chains, MT76_SKU_RATE);
+
+ val = mt76_get_of_array_s8(np, "rates-ofdm", &len, ARRAY_SIZE(dest->ofdm));
+ mt76_apply_array_limit(dev, dest->ofdm, ARRAY_SIZE(dest->ofdm), val,
+ target_power, txs_delta, &max_power, n_chains, MT76_SKU_RATE);
+
+ val = mt76_get_of_array_s8(np, "rates-mcs", &len,
+ ARRAY_SIZE(dest->mcs[0]) + 1);
+ mt76_apply_multi_array_limit(dev, dest->mcs[0], ARRAY_SIZE(dest->mcs[0]),
+ ARRAY_SIZE(dest->mcs), val, len, target_power,
+ txs_delta, &max_power, n_chains, MT76_SKU_RATE);
+
+ val = mt76_get_of_array_s8(np, "rates-ru", &len,
+ ARRAY_SIZE(dest->ru[0]) + 1);
+ mt76_apply_multi_array_limit(dev, dest->ru[0], ARRAY_SIZE(dest->ru[0]),
+ ARRAY_SIZE(dest->ru), val, len, target_power,
+ txs_delta, &max_power, n_chains, MT76_SKU_RATE);
+
+ val = mt76_get_of_array_s8(np, "paths-cck", &len,
+ ARRAY_SIZE(dest->path.cck));
+ mt76_apply_array_limit(dev, dest->path.cck, ARRAY_SIZE(dest->path.cck), val,
+ target_power, txs_delta, &max_power, n_chains, MT76_SKU_BACKOFF);
+
+ val = mt76_get_of_array_s8(np, "paths-ofdm", &len,
+ ARRAY_SIZE(dest->path.ofdm));
+ mt76_apply_array_limit(dev, dest->path.ofdm, ARRAY_SIZE(dest->path.ofdm), val,
+ target_power, txs_delta, &max_power, n_chains, MT76_SKU_BACKOFF);
+
+ val = mt76_get_of_array_s8(np, "paths-ofdm-bf", &len,
+ ARRAY_SIZE(dest->path.ofdm_bf));
+ mt76_apply_array_limit(dev, dest->path.ofdm_bf, ARRAY_SIZE(dest->path.ofdm_bf), val,
+ target_power, txs_delta, &max_power, n_chains,
+ MT76_SKU_BACKOFF_BF_OFFSET);
+
+ val = mt76_get_of_array_s8(np, "paths-ru", &len,
+ ARRAY_SIZE(dest->path.ru[0]) + 1);
+ mt76_apply_multi_array_limit(dev, dest->path.ru[0], ARRAY_SIZE(dest->path.ru[0]),
+ ARRAY_SIZE(dest->path.ru), val, len, target_power,
+ txs_delta, &max_power, n_chains, MT76_SKU_BACKOFF);
+
+ val = mt76_get_of_array_s8(np, "paths-ru-bf", &len,
+ ARRAY_SIZE(dest->path.ru_bf[0]) + 1);
+ mt76_apply_multi_array_limit(dev, dest->path.ru_bf[0], ARRAY_SIZE(dest->path.ru_bf[0]),
+ ARRAY_SIZE(dest->path.ru_bf), val, len, target_power,
+ txs_delta, &max_power, n_chains, MT76_SKU_BACKOFF);
return max_power;
}
diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h b/drivers/net/wireless/mediatek/mt76/mt76.h
index d05e83ea1..32876eab2 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76.h
+++ b/drivers/net/wireless/mediatek/mt76/mt76.h
@@ -540,7 +540,6 @@ struct mt76_driver_ops {
u32 survey_flags;
u16 txwi_size;
u16 token_size;
- u8 mcs_rates;
unsigned int link_data_size;
--
2.45.2
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