[PATCH 1/3] dt-bindings: net: wireless: mt76: add power-limits node

[PATCH 1/3] dt-bindings: net: wireless: mt76: add power-limits node

[Felix Fietkau]

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>
---
 .../bindings/net/wireless/mediatek,mt76.txt   | 47 +++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/wireless/mediatek,mt76.txt b/Documentation/devicetree/bindings/net/wireless/mediatek,mt76.txt
index ab7e7a00e534..9d9ace0cfbf9 100644
--- a/Documentation/devicetree/bindings/net/wireless/mediatek,mt76.txt
+++ b/Documentation/devicetree/bindings/net/wireless/mediatek,mt76.txt
@@ -36,6 +36,7 @@ Optional nodes:
 - led: Properties for a connected LED
   Optional properties:
     - led-sources: See Documentation/devicetree/bindings/leds/common.txt
+- power-limits: contains per-regdomain/channel rate power limit subnodes
 
 &pcie {
 	pcie0 {
@@ -76,3 +77,49 @@ wmac: wmac@18000000 {
 
 	power-domains = <&scpsys MT7622_POWER_DOMAIN_WB>;
 };
+
+
+Subnodes of power-limits:
+
+Properties:
+- country: One or more country codes, as used by the cfg80211 regdomain code
+- regdomain: "FCC", "ETSI" or "JP"
+
+If neither country, nor regdomain is specified, the power limits node is used
+as a fallback when no other subnode matches.
+
+Subnodes txpower-2g, txpower-5g:
+
+Properties:
+- channels: pairs of first and last channel number
+- cck: 4 half-dBm per-rate power limit values
+- ofdm: 8 half-dBm per-rate power limit values
+- mcs:
+	sets of per-rate power limit values for 802.11n/802.11ac rates for
+	multiple channel bandwidth settings.
+	Each set starts with the number of channel bandwidth settings for
+	which the rate set applies, followed by either 8 (MT7603/MT7628) or
+	10 (all other chips) power limit values.
+	The order of the channel bandwidth settings is: 20, 40, 80, 160 MHz.
+
+
+power-limit example:
+
+power-limits {
+	r0 {
+		regdomain = "FCC";
+		txpower-5g {
+			r1 {
+				channels = <36 48>;
+				ofdm = <23 23 23 23 23 23 23 23>;
+				mcs = <1 23 23 23 23 23 23 23 23 23 23>,
+					  <3 22 22 22 22 22 22 22 22 22 22>;
+			};
+			r2 {
+				channels = <100 181>;
+				ofdm = <14 14 14 14 14 14 14 14>;
+				mcs = <4 14 14 14 14 14 14 14 14 14 14>;
+			};
+		};
+	};
+};
-- 
2.24.0

[PATCH 2/3] mt76: add functions for parsing rate power limits from DT

[Felix Fietkau]

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>
---
 drivers/net/wireless/mediatek/mt76/eeprom.c | 203 ++++++++++++++++++++
 drivers/net/wireless/mediatek/mt76/mt76.h   |  13 ++
 2 files changed, 216 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/eeprom.c b/drivers/net/wireless/mediatek/mt76/eeprom.c
index c236e303ccfd..334606b07693 100644
--- a/drivers/net/wireless/mediatek/mt76/eeprom.c
+++ b/drivers/net/wireless/mediatek/mt76/eeprom.c
@@ -104,6 +104,209 @@ mt76_eeprom_override(struct mt76_dev *dev)
 }
 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;
+
+	if (nss >= 4)
+		return 0;
+
+	val = mt76_get_of_array(np, "txs_delta", &len, 3);
+	return be32_to_cpu(val[3 - nss]);
+}
+
+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, "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, "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, "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 dfe625a53c63..64cafc0caa33 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76.h
+++ b/drivers/net/wireless/mediatek/mt76/mt76.h
@@ -306,6 +306,7 @@ struct mt76_driver_ops {
 	u32 drv_flags;
 	u32 survey_flags;
 	u16 txwi_size;
+	u8 mcs_rates;
 
 	void (*update_survey)(struct mt76_dev *dev);
 
@@ -558,6 +559,7 @@ struct mt76_dev {
 
 	struct mt76_rate_power rate_power;
 
+	char alpha2[3];
 	enum nl80211_dfs_regions region;
 
 	u32 debugfs_reg;
@@ -577,6 +579,12 @@ 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,
@@ -959,4 +967,9 @@ struct sk_buff *mt76_mcu_get_response(struct mt76_dev *dev,
 
 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
-- 
2.24.0

[PATCH 3/3] mt76: mt7615: implement support for using DT rate power limits

[Felix Fietkau]

Limits are used to update the channel max_power settings and also passed
to the firmware on channel changes

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 .../net/wireless/mediatek/mt76/mt7615/init.c  | 11 +++-
 .../net/wireless/mediatek/mt76/mt7615/mcu.c   | 61 ++++++++++++++++++-
 2 files changed, 70 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/init.c b/drivers/net/wireless/mediatek/mt76/mt7615/init.c
index e2d80518e5af..04a32123e7fe 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7615/init.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7615/init.c
@@ -234,6 +234,7 @@ void mt7615_init_txpower(struct mt7615_dev *dev,
 	int delta_idx, delta = mt76_tx_power_nss_delta(n_chains);
 	u8 *eep = (u8 *)dev->mt76.eeprom.data;
 	enum nl80211_band band = sband->band;
+	struct mt76_power_limits limits;
 	u8 rate_val;
 
 	delta_idx = mt7615_eeprom_get_power_delta_index(dev, band);
@@ -262,7 +263,11 @@ void mt7615_init_txpower(struct mt7615_dev *dev,
 			target_power = max(target_power, eep[index]);
 		}
 
-		target_power = DIV_ROUND_UP(target_power + delta, 2);
+		target_power += delta;
+		target_power = mt76_get_rate_power_limits(&dev->mphy, chan,
+							  &limits,
+							  target_power);
+		target_power = DIV_ROUND_UP(target_power, 2);
 		chan->max_power = min_t(int, chan->max_reg_power,
 					target_power);
 		chan->orig_mpwr = target_power;
@@ -280,8 +285,12 @@ mt7615_regd_notifier(struct wiphy *wiphy,
 	struct mt7615_phy *phy = mphy->priv;
 	struct cfg80211_chan_def *chandef = &mphy->chandef;
 
+	memcpy(dev->mt76.alpha2, request->alpha2, sizeof(dev->mt76.alpha2));
 	dev->mt76.region = request->dfs_region;
 
+	mt7615_init_txpower(dev, &mphy->sband_2g.sband);
+	mt7615_init_txpower(dev, &mphy->sband_5g.sband);
+
 	if (!(chandef->chan->flags & IEEE80211_CHAN_RADAR))
 		return;
 
diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7615/mcu.c
index 6e869b8c5e26..0b1933111004 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7615/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7615/mcu.c
@@ -2654,16 +2654,75 @@ static void mt7615_mcu_set_txpower_sku(struct mt7615_phy *phy, u8 *sku)
 {
 	struct mt76_phy *mphy = phy->mt76;
 	struct ieee80211_hw *hw = mphy->hw;
+	struct mt76_power_limits limits;
+	s8 *limits_array = (s8 *)&limits;
 	int n_chains = hweight8(mphy->antenna_mask);
 	int tx_power;
 	int i;
+	static const u8 sku_mapping[] = {
+#define SKU_FIELD(_type, _field) \
+		[MT_SKU_##_type] = offsetof(struct mt76_power_limits, _field)
+		SKU_FIELD(CCK_1_2, cck[0]),
+		SKU_FIELD(CCK_55_11, cck[2]),
+		SKU_FIELD(OFDM_6_9, ofdm[0]),
+		SKU_FIELD(OFDM_12_18, ofdm[2]),
+		SKU_FIELD(OFDM_24_36, ofdm[4]),
+		SKU_FIELD(OFDM_48, ofdm[6]),
+		SKU_FIELD(OFDM_54, ofdm[7]),
+		SKU_FIELD(HT20_0_8, mcs[0][0]),
+		SKU_FIELD(HT20_32, ofdm[0]),
+		SKU_FIELD(HT20_1_2_9_10, mcs[0][1]),
+		SKU_FIELD(HT20_3_4_11_12, mcs[0][3]),
+		SKU_FIELD(HT20_5_13, mcs[0][5]),
+		SKU_FIELD(HT20_6_14, mcs[0][6]),
+		SKU_FIELD(HT20_7_15, mcs[0][7]),
+		SKU_FIELD(HT40_0_8, mcs[1][0]),
+		SKU_FIELD(HT40_32, ofdm[0]),
+		SKU_FIELD(HT40_1_2_9_10, mcs[1][1]),
+		SKU_FIELD(HT40_3_4_11_12, mcs[1][3]),
+		SKU_FIELD(HT40_5_13, mcs[1][5]),
+		SKU_FIELD(HT40_6_14, mcs[1][6]),
+		SKU_FIELD(HT40_7_15, mcs[1][7]),
+		SKU_FIELD(VHT20_0, mcs[0][0]),
+		SKU_FIELD(VHT20_1_2, mcs[0][1]),
+		SKU_FIELD(VHT20_3_4, mcs[0][3]),
+		SKU_FIELD(VHT20_5_6, mcs[0][5]),
+		SKU_FIELD(VHT20_7, mcs[0][7]),
+		SKU_FIELD(VHT20_8, mcs[0][8]),
+		SKU_FIELD(VHT20_9, mcs[0][9]),
+		SKU_FIELD(VHT40_0, mcs[1][0]),
+		SKU_FIELD(VHT40_1_2, mcs[1][1]),
+		SKU_FIELD(VHT40_3_4, mcs[1][3]),
+		SKU_FIELD(VHT40_5_6, mcs[1][5]),
+		SKU_FIELD(VHT40_7, mcs[1][7]),
+		SKU_FIELD(VHT40_8, mcs[1][8]),
+		SKU_FIELD(VHT40_9, mcs[1][9]),
+		SKU_FIELD(VHT80_0, mcs[2][0]),
+		SKU_FIELD(VHT80_1_2, mcs[2][1]),
+		SKU_FIELD(VHT80_3_4, mcs[2][3]),
+		SKU_FIELD(VHT80_5_6, mcs[2][5]),
+		SKU_FIELD(VHT80_7, mcs[2][7]),
+		SKU_FIELD(VHT80_8, mcs[2][8]),
+		SKU_FIELD(VHT80_9, mcs[2][9]),
+		SKU_FIELD(VHT160_0, mcs[3][0]),
+		SKU_FIELD(VHT160_1_2, mcs[3][1]),
+		SKU_FIELD(VHT160_3_4, mcs[3][3]),
+		SKU_FIELD(VHT160_5_6, mcs[3][5]),
+		SKU_FIELD(VHT160_7, mcs[3][7]),
+		SKU_FIELD(VHT160_8, mcs[3][8]),
+		SKU_FIELD(VHT160_9, mcs[3][9]),
+#undef SKU_FIELD
+	};
 
 	tx_power = hw->conf.power_level * 2 -
 		   mt76_tx_power_nss_delta(n_chains);
+
+	tx_power = mt76_get_rate_power_limits(mphy, mphy->chandef.chan,
+					      &limits, tx_power);
 	mphy->txpower_cur = tx_power;
 
 	for (i = 0; i < MT_SKU_1SS_DELTA; i++)
-		sku[i] = tx_power;
+		sku[i] = limits_array[sku_mapping[i]];
 
 	for (i = 0; i < 4; i++) {
 		int delta = 0;
-- 
2.24.0

Re: [PATCH 1/3] dt-bindings: net: wireless: mt76: add power-limits node

[Rob Herring]

On Fri, May 29, 2020 at 06:19:27PM +0200, Felix Fietkau wrote:
> 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

How do other WiFi chips handle this? If this is added to DT, then it 
should be common for all WiFi h/w.
 
> Signed-off-by: Felix Fietkau <nbd@nbd.name>
> ---
>  .../bindings/net/wireless/mediatek,mt76.txt   | 47 +++++++++++++++++++
>  1 file changed, 47 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/net/wireless/mediatek,mt76.txt b/Documentation/devicetree/bindings/net/wireless/mediatek,mt76.txt
> index ab7e7a00e534..9d9ace0cfbf9 100644
> --- a/Documentation/devicetree/bindings/net/wireless/mediatek,mt76.txt
> +++ b/Documentation/devicetree/bindings/net/wireless/mediatek,mt76.txt
> @@ -36,6 +36,7 @@ Optional nodes:
>  - led: Properties for a connected LED
>    Optional properties:
>      - led-sources: See Documentation/devicetree/bindings/leds/common.txt
> +- power-limits: contains per-regdomain/channel rate power limit subnodes
>  
>  &pcie {
>  	pcie0 {
> @@ -76,3 +77,49 @@ wmac: wmac@18000000 {
>  
>  	power-domains = <&scpsys MT7622_POWER_DOMAIN_WB>;
>  };
> +
> +
> +Subnodes of power-limits:
> +
> +Properties:
> +- country: One or more country codes, as used by the cfg80211 regdomain code
> +- regdomain: "FCC", "ETSI" or "JP"
> +
> +If neither country, nor regdomain is specified, the power limits node is used
> +as a fallback when no other subnode matches.
> +
> +Subnodes txpower-2g, txpower-5g:
> +
> +Properties:
> +- channels: pairs of first and last channel number
> +- cck: 4 half-dBm per-rate power limit values
> +- ofdm: 8 half-dBm per-rate power limit values
> +- mcs:
> +	sets of per-rate power limit values for 802.11n/802.11ac rates for
> +	multiple channel bandwidth settings.
> +	Each set starts with the number of channel bandwidth settings for
> +	which the rate set applies, followed by either 8 (MT7603/MT7628) or
> +	10 (all other chips) power limit values.
> +	The order of the channel bandwidth settings is: 20, 40, 80, 160 MHz.
> +
> +
> +power-limit example:
> +
> +power-limits {
> +	r0 {
> +		regdomain = "FCC";
> +		txpower-5g {
> +			r1 {
> +				channels = <36 48>;
> +				ofdm = <23 23 23 23 23 23 23 23>;
> +				mcs = <1 23 23 23 23 23 23 23 23 23 23>,
> +					  <3 22 22 22 22 22 22 22 22 22 22>;
> +			};
> +			r2 {
> +				channels = <100 181>;
> +				ofdm = <14 14 14 14 14 14 14 14>;
> +				mcs = <4 14 14 14 14 14 14 14 14 14 14>;
> +			};
> +		};
> +	};
> +};
> -- 
> 2.24.0
> 

Re: [PATCH 1/3] dt-bindings: net: wireless: mt76: add power-limits node

[Felix Fietkau]

On 2020-05-29 23:26, Rob Herring wrote:
> On Fri, May 29, 2020 at 06:19:27PM +0200, Felix Fietkau wrote:
>> 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
> 
> How do other WiFi chips handle this? If this is added to DT, then it 
> should be common for all WiFi h/w.
Most devices store this data in EEPROM, and the way it's handled also
varies across different chips. QCA has EEPROM data that only provides
limits for edge channels (called "conformance test limits")
The only other example I could find of a driver that stores it in DT is
mwifiex, which uses an opaque short array of bytes that is passed to the
firmware directly.
So I don't think it makes sense to put this in the common bindings.
On the other hand, I did try to keep the format as generic and
extensible as possible, so we could always move it over from mt76 to the
common binding once we encounter another driver that needs something
like this.

- Felix