mt76: add functions for parsing rate power limits from DT

This subnode can be used to set per-rate tx power limits either per
country code / regdomain or globally.
These limits are typically provided by the device manufacturers and are
used to limit sideband emissions and stay within regulatory limits

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

diff --git a/drivers/net/wireless/mediatek/mt76/eeprom.c b/drivers/net/wireless/mediatek/mt76/eeprom.c
index 6d895738222ad581b9611f65735a76073dc354f4..2dbc371654cd830cc696595a77a15afa7bbb03c6 100644 (file)
--- a/drivers/net/wireless/mediatek/mt76/eeprom.c
+++ b/drivers/net/wireless/mediatek/mt76/eeprom.c
@@ -104,6 +104,210 @@ mt76_eeprom_override(struct mt76_phy *phy)
 }
 EXPORT_SYMBOL_GPL(mt76_eeprom_override);
 
+static bool mt76_string_prop_find(struct property *prop, const char *str)
+{
+       const char *cp = NULL;
+
+       if (!prop || !str || !str[0])
+               return false;
+
+       while ((cp = of_prop_next_string(prop, cp)) != NULL)
+               if (!strcasecmp(cp, str))
+                       return true;
+
+       return false;
+}
+
+static struct device_node *
+mt76_find_power_limits_node(struct mt76_dev *dev)
+{
+       struct device_node *np = dev->dev->of_node;
+       const char *const region_names[] = {
+               [NL80211_DFS_ETSI] = "etsi",
+               [NL80211_DFS_FCC] = "fcc",
+               [NL80211_DFS_JP] = "jp",
+       };
+       struct device_node *cur, *fallback = NULL;
+       const char *region_name = NULL;
+
+       if (dev->region < ARRAY_SIZE(region_names))
+               region_name = region_names[dev->region];
+
+       np = of_get_child_by_name(np, "power-limits");
+       if (!np)
+               return NULL;
+
+       for_each_child_of_node(np, cur) {
+               struct property *country = of_find_property(cur, "country", NULL);
+               struct property *regd = of_find_property(cur, "regdomain", NULL);
+
+               if (!country && !regd) {
+                       fallback = cur;
+                       continue;
+               }
+
+               if (mt76_string_prop_find(country, dev->alpha2) ||
+                   mt76_string_prop_find(regd, region_name))
+                       return cur;
+       }
+
+       return fallback;
+}
+
+static const __be32 *
+mt76_get_of_array(struct device_node *np, char *name, size_t *len, int min)
+{
+       struct property *prop = of_find_property(np, name, NULL);
+
+       if (!prop || !prop->value || prop->length < min * 4)
+               return NULL;
+
+       *len = prop->length;
+
+       return prop->value;
+}
+
+static struct device_node *
+mt76_find_channel_node(struct device_node *np, struct ieee80211_channel *chan)
+{
+       struct device_node *cur;
+       const __be32 *val;
+       size_t len;
+
+       for_each_child_of_node(np, cur) {
+               val = mt76_get_of_array(cur, "channels", &len, 2);
+               if (!val)
+                       continue;
+
+               while (len >= 2 * sizeof(*val)) {
+                       if (chan->hw_value >= be32_to_cpu(val[0]) &&
+                           chan->hw_value <= be32_to_cpu(val[1]))
+                               return cur;
+
+                       val += 2;
+                       len -= 2 * sizeof(*val);
+               }
+       }
+
+       return NULL;
+}
+
+static s8
+mt76_get_txs_delta(struct device_node *np, u8 nss)
+{
+       const __be32 *val;
+       size_t len;
+
+       val = mt76_get_of_array(np, "txs-delta", &len, nss);
+       if (!val)
+               return 0;
+
+       return be32_to_cpu(val[nss - 1]);
+}
+
+static void
+mt76_apply_array_limit(s8 *pwr, size_t pwr_len, const __be32 *data,
+                      s8 target_power, s8 nss_delta, s8 *max_power)
+{
+       int i;
+
+       if (!data)
+               return;
+
+       for (i = 0; i < pwr_len; i++) {
+               pwr[i] = min_t(s8, target_power,
+                              be32_to_cpu(data[i]) + nss_delta);
+               *max_power = max(*max_power, pwr[i]);
+       }
+}
+
+s8 mt76_get_rate_power_limits(struct mt76_phy *phy,
+                             struct ieee80211_channel *chan,
+                             struct mt76_power_limits *dest,
+                             s8 target_power)
+{
+       struct mt76_dev *dev = phy->dev;
+       struct device_node *np;
+       const __be32 *val;
+       char name[16];
+       u32 mcs_rates = dev->drv->mcs_rates;
+       char band;
+       size_t len;
+       int i, cur;
+       s8 max_power = 0;
+       s8 txs_delta;
+
+       if (!mcs_rates)
+               mcs_rates = 10;
+
+       memset(dest, target_power, sizeof(*dest));
+
+       if (!IS_ENABLED(CONFIG_OF))
+               return target_power;
+
+       np = mt76_find_power_limits_node(dev);
+       if (!np)
+               return target_power;
+
+       switch (chan->band) {
+       case NL80211_BAND_2GHZ:
+               band = '2';
+               break;
+       case NL80211_BAND_5GHZ:
+               band = '5';
+               break;
+       default:
+               return target_power;
+       }
+
+       snprintf(name, sizeof(name), "txpower-%cg", band);
+       np = of_get_child_by_name(np, name);
+       if (!np)
+               return target_power;
+
+       np = mt76_find_channel_node(np, chan);
+       if (!np)
+               return target_power;
+
+       txs_delta = mt76_get_txs_delta(np, hweight8(phy->antenna_mask));
+
+       val = mt76_get_of_array(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(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(np, "rates-mcs", &len, mcs_rates + 1);
+       if (!val)
+               return max_power;
+
+       len /= 4;
+       cur = be32_to_cpu(val[0]);
+       for (i = 0; i < ARRAY_SIZE(dest->mcs); i++) {
+               if (len < mcs_rates + 1)
+                       break;
+
+               mt76_apply_array_limit(dest->mcs[i], ARRAY_SIZE(dest->mcs[i]),
+                                      val + 1, target_power, txs_delta,
+                                      &max_power);
+               if (--cur > 0)
+                       continue;
+
+               val += mcs_rates + 1;
+               len -= mcs_rates + 1;
+               if (!len)
+                       break;
+
+               cur = be32_to_cpu(val[0]);
+       }
+
+       return max_power;
+}
+EXPORT_SYMBOL_GPL(mt76_get_rate_power_limits);
+
 int
 mt76_eeprom_init(struct mt76_dev *dev, int len)
 {

diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h b/drivers/net/wireless/mediatek/mt76/mt76.h
index d60a1dd8f31413f3c0e3c433b70fc9447a95c4f7..122a58c87f4655e4134332c986bb429030c82e48 100644 (file)
--- a/drivers/net/wireless/mediatek/mt76/mt76.h
+++ b/drivers/net/wireless/mediatek/mt76/mt76.h
@@ -331,6 +331,7 @@ struct mt76_driver_ops {
        u32 drv_flags;
        u32 survey_flags;
        u16 txwi_size;
+       u8 mcs_rates;
 
        void (*update_survey)(struct mt76_dev *dev);
 
@@ -711,6 +712,12 @@ struct mt76_dev {
        };
 };
 
+struct mt76_power_limits {
+       s8 cck[4];
+       s8 ofdm[8];
+       s8 mcs[4][10];
+};
+
 enum mt76_phy_type {
        MT_PHY_TYPE_CCK,
        MT_PHY_TYPE_OFDM,
@@ -1195,4 +1202,9 @@ mt76_mcu_skb_send_msg(struct mt76_dev *dev, struct sk_buff *skb, int cmd,
 
 void mt76_set_irq_mask(struct mt76_dev *dev, u32 addr, u32 clear, u32 set);
 
+s8 mt76_get_rate_power_limits(struct mt76_phy *phy,
+                             struct ieee80211_channel *chan,
+                             struct mt76_power_limits *dest,
+                             s8 target_power);
+
 #endif