[PATCH rtw-next] wifi: rtw88: honour the transmit power mac80211 asks for

[Mehmet Fide]

From: Mehmet Fide <mehmet.fide@xxxxxxxxxxxxxxxxxx>

The per-rate power index is the by-rate value capped by the regulatory
limit and the SAR limit; the level mac80211 hands over in conf.power_level
is never looked at, so "iw phy <phy> set txpower fixed <mBm>" is accepted
and silently ignored. Devices that share a small enclosure with their
client, or that must back off for coexistence, have no way to run below
the regulatory maximum.

Treat the requested level like the SAR limit: convert the dBm value to
the by-rate offset domain with the chip's gain index granularity and use
it as one more ceiling on the offset, then program the indices again
whenever the level changes. The level is the total the device may
radiate, so with two, three or four transmit paths each path gets 3, 5
or 6 dB less, the way ath9k and the vendor driver share it. mac80211
hands over the minimum of the regulatory maximum and the user's request,
so a channel's maximum is respected as well; before the first
configuration there is no request and nothing is capped, which keeps the
behaviour of a driver that does not honour the level at all.

Tested on RTL8822BU (2T) and RTL8821CU (1T) in AP mode: "fixed 1000"
moves every rate that sat above 10 dBm down to the 10 dBm index, less
the 3 dB path share on the 8822BU, while the rates already below stay,
"auto" restores the tables and the client stays associated through the
changes; a second radio saw the beacons drop by the requested amount.

Signed-off-by: Mehmet Fide <mehmet.fide@xxxxxxxxxxxxxxxxxx>
---
 drivers/net/wireless/realtek/rtw88/mac80211.c |  3 +++
 drivers/net/wireless/realtek/rtw88/phy.c      | 26 +++++++++++++++++++
 drivers/net/wireless/realtek/rtw88/phy.h      |  1 +
 3 files changed, 30 insertions(+)

diff --git a/drivers/net/wireless/realtek/rtw88/mac80211.c b/drivers/net/wireless/realtek/rtw88/mac80211.c
index 2a9b09fa76e7..e0462e934438 100644
--- a/drivers/net/wireless/realtek/rtw88/mac80211.c
+++ b/drivers/net/wireless/realtek/rtw88/mac80211.c
@@ -3,6 +3,7 @@
  */
 
 #include "main.h"
+#include "phy.h"
 #include "sec.h"
 #include "tx.h"
 #include "fw.h"
@@ -94,6 +95,8 @@ static int rtw_ops_config(struct ieee80211_hw *hw, int radio_idx, u32 changed)
 
 	if (changed & IEEE80211_CONF_CHANGE_CHANNEL)
 		rtw_set_channel(rtwdev);
+	else if (changed & IEEE80211_CONF_CHANGE_POWER)
+		rtw_phy_set_tx_power_level(rtwdev, rtwdev->hal.current_channel);
 
 	if ((changed & IEEE80211_CONF_CHANGE_IDLE) &&
 	    (hw->conf.flags & IEEE80211_CONF_IDLE) &&
diff --git a/drivers/net/wireless/realtek/rtw88/phy.c b/drivers/net/wireless/realtek/rtw88/phy.c
index e2ac5c6fd500..0dfcd0739423 100644
--- a/drivers/net/wireless/realtek/rtw88/phy.c
+++ b/drivers/net/wireless/realtek/rtw88/phy.c
@@ -2236,6 +2236,29 @@ static s8 rtw_phy_get_tx_power_sar(struct rtw_dev *rtwdev, u8 sar_band,
 	return (s8)rtwdev->chip->max_power_index;
 }
 
+static s8 rtw_phy_get_tx_power_user(struct rtw_dev *rtwdev, u8 band, u8 path,
+				    u8 rate)
+{
+	struct rtw_hal *hal = &rtwdev->hal;
+	const struct rtw_chip_info *chip = rtwdev->chip;
+	static const u8 path_share_dbm[] = { 0, 0, 3, 5, 6 };
+	int power_level = rtwdev->hw->conf.power_level;
+	u8 rs = rtw_phy_rate_to_rate_section(rate);
+	u8 paths = clamp_t(u8, hweight8(hal->antenna_tx), 1, 4);
+	s32 idx;
+	s8 base;
+
+	if (power_level <= 0 || rs == RTW_RATE_SECTION_NUM)
+		return (s8)chip->max_power_index;
+
+	idx = (power_level - path_share_dbm[paths]) << chip->txgi_factor;
+	base = band == PHY_BAND_2G ? hal->tx_pwr_by_rate_base_2g[path][rs] :
+				     hal->tx_pwr_by_rate_base_5g[path][rs];
+
+	return (s8)clamp_t(s32, idx, -chip->max_power_index - 1,
+			   chip->max_power_index) - base;
+}
+
 void rtw_get_tx_power_params(struct rtw_dev *rtwdev, u8 path, u8 rate, u8 bw,
 			     u8 ch, u8 regd, struct rtw_power_params *pwr_param)
 {
@@ -2248,6 +2271,7 @@ void rtw_get_tx_power_params(struct rtw_dev *rtwdev, u8 path, u8 rate, u8 bw,
 	s8 *limit = &pwr_param->pwr_limit;
 	s8 *remnant = &pwr_param->pwr_remnant;
 	s8 *sar = &pwr_param->pwr_sar;
+	s8 *user = &pwr_param->pwr_user;
 
 	pwr_idx = &rtwdev->efuse.txpwr_idx_table[path];
 	group = rtw_get_channel_group(ch, rate);
@@ -2272,6 +2296,7 @@ void rtw_get_tx_power_params(struct rtw_dev *rtwdev, u8 path, u8 rate, u8 bw,
 	*remnant = rate <= DESC_RATE11M ? dm_info->txagc_remnant_cck :
 					  dm_info->txagc_remnant_ofdm[path];
 	*sar = rtw_phy_get_tx_power_sar(rtwdev, hal->sar_band, path, rate);
+	*user = rtw_phy_get_tx_power_user(rtwdev, band, path, rate);
 }
 
 u8
@@ -2289,6 +2314,7 @@ rtw_phy_get_tx_power_index(struct rtw_dev *rtwdev, u8 rf_path, u8 rate,
 	offset = min3(pwr_param.pwr_offset,
 		      pwr_param.pwr_limit,
 		      pwr_param.pwr_sar);
+	offset = min(offset, pwr_param.pwr_user);
 
 	if (rtwdev->chip->en_dis_dpd)
 		offset += rtw_phy_get_dis_dpd_by_rate_diff(rtwdev, rate);
diff --git a/drivers/net/wireless/realtek/rtw88/phy.h b/drivers/net/wireless/realtek/rtw88/phy.h
index 8449936497bb..c26f18348709 100644
--- a/drivers/net/wireless/realtek/rtw88/phy.h
+++ b/drivers/net/wireless/realtek/rtw88/phy.h
@@ -155,6 +155,7 @@ struct rtw_power_params {
 	s8 pwr_limit;
 	s8 pwr_remnant;
 	s8 pwr_sar;
+	s8 pwr_user;
 };
 
 void
-- 
2.55.0