mac80211: rt2x00: experimental improvements for MT7620 wifi

Serge Vasilugin reports:

To improve mt7620 built-in wifi performance some changes:
1. Correct BW20/BW40 switching (see comments with mark (1))
2. Correct TX_SW_CFG1 MAC reg from v3 of vendor driver see
	https://gitlab.com/dm38/padavan-ng/-/blob/master/trunk/proprietary/rt_wifi/rtpci/3.0.X.X/mt76x2/chips/rt6352.c#L531
3. Set bbp66 for all chains.
4. US_CYC_CNT init based on Programming guide, default value was 33 (pci),
   set chipset bus clock with fallback to cpu clock/3.
5. Don't overwrite default values for mt7620.
6. Correct some typos.
7. Add support for external LNA:
    a) RF and BBP regs never be corrected for this mode
    b) eLNA is driven the same way as ePA with mt7620's pin PA
	but vendor driver explicitly pin PA to gpio mode (for forrect calibration?)
	so I'm not sure that request for pa_pin in dts-file will be enough

First 5 changes (really 2) improve performance for boards w/o eLNA/ePA.
Changes 7 add support for eLNA

Configuration w/o eLAN/ePA and with eLNA show results
tx/rx (from router point of view) for each stream:
 35-40/30-35 Mbps for HT20
 65-70/60-65 Mbps for HT40

Yes. Max results for 2T2R client is 140-145/135-140
with peaks 160/150, It correspond to mediatek driver results.
Boards with ePA untested.

Reported-by: Serge Vasilugin <vasilugin@yandex.ru>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
[directly include v3 of the patchset submitted upstream]
(cherry picked from commit 31a6605de04218e1c04bd5c2436c24d7d1c07506)
(cherry picked from commit e785ca05e9f0502894772f5df92192b816ba5d7c)
(cherry picked from commit 412fcf3d4400f84551f3ead0514834c62d94a251)

1 files changed, 178 insertions, 0 deletions

diff --git a/package/kernel/mac80211/patches/rt2x00/004-rt2x00-move-up-and-reuse-busy-wait-functions.patch b/package/kernel/mac80211/patches/rt2x00/004-rt2x00-move-up-and-reuse-busy-wait-functions.patch
new file mode 100644
index 0000000000..da453074a1
--- /dev/null
+++ b/package/kernel/mac80211/patches/rt2x00/004-rt2x00-move-up-and-reuse-busy-wait-functions.patch
@@ -0,0 +1,178 @@
+From patchwork Sat Sep 17 20:27:10 2022
+Content-Type: text/plain; charset="utf-8"
+MIME-Version: 1.0
+Content-Transfer-Encoding: 7bit
+X-Patchwork-Submitter: Daniel Golle <daniel@makrotopia.org>
+X-Patchwork-Id: 12979245
+X-Patchwork-Delegate: kvalo@adurom.com
+Return-Path: <linux-wireless-owner@kernel.org>
+Date: Sat, 17 Sep 2022 21:27:10 +0100
+From: Daniel Golle <daniel@makrotopia.org>
+To: linux-wireless@vger.kernel.org, Stanislaw Gruszka <stf_xl@wp.pl>,
+        Helmut Schaa <helmut.schaa@googlemail.com>
+Cc: Kalle Valo <kvalo@kernel.org>,
+        "David S. Miller" <davem@davemloft.net>,
+        Eric Dumazet <edumazet@google.com>,
+        Jakub Kicinski <kuba@kernel.org>,
+        Paolo Abeni <pabeni@redhat.com>,
+        Johannes Berg <johannes.berg@intel.com>
+Subject: [PATCH v3 04/16] rt2x00: move up and reuse busy wait functions
+Message-ID: 
+ <3fdb9dc15e76a9f9c1948b4a3a1308a7a5677bb8.1663445157.git.daniel@makrotopia.org>
+References: <cover.1663445157.git.daniel@makrotopia.org>
+MIME-Version: 1.0
+Content-Disposition: inline
+In-Reply-To: <cover.1663445157.git.daniel@makrotopia.org>
+Precedence: bulk
+List-ID: <linux-wireless.vger.kernel.org>
+X-Mailing-List: linux-wireless@vger.kernel.org
+
+Move bbp_ready and rf_ready busy wait functions up in the code so they
+can more easily be used. Allow specifying register mask in rf_ready
+function which is useful for calibration routines which will be added
+in follow-up commits.
+
+Signed-off-by: Daniel Golle <daniel@makrotopia.org>
+Acked-by: Stanislaw Gruszka <stf_xl@wp.pl>
+---
+ .../net/wireless/ralink/rt2x00/rt2800lib.c    | 99 +++++++++----------
+ 1 file changed, 46 insertions(+), 53 deletions(-)
+
+--- a/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
++++ b/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
+@@ -2143,6 +2143,48 @@ void rt2800_config_erp(struct rt2x00_dev
+ }
+ EXPORT_SYMBOL_GPL(rt2800_config_erp);
+ 
++static int rt2800_wait_bbp_rf_ready(struct rt2x00_dev *rt2x00dev,
++				    const struct rt2x00_field32 mask)
++{
++	unsigned int i;
++	u32 reg;
++
++	for (i = 0; i < REGISTER_BUSY_COUNT; i++) {
++		reg = rt2800_register_read(rt2x00dev, MAC_STATUS_CFG);
++		if (!rt2x00_get_field32(reg, mask))
++			return 0;
++
++		udelay(REGISTER_BUSY_DELAY);
++	}
++
++	rt2x00_err(rt2x00dev, "BBP/RF register access failed, aborting\n");
++	return -EACCES;
++}
++
++static int rt2800_wait_bbp_ready(struct rt2x00_dev *rt2x00dev)
++{
++	unsigned int i;
++	u8 value;
++
++	/*
++	 * BBP was enabled after firmware was loaded,
++	 * but we need to reactivate it now.
++	 */
++	rt2800_register_write(rt2x00dev, H2M_BBP_AGENT, 0);
++	rt2800_register_write(rt2x00dev, H2M_MAILBOX_CSR, 0);
++	msleep(1);
++
++	for (i = 0; i < REGISTER_BUSY_COUNT; i++) {
++		value = rt2800_bbp_read(rt2x00dev, 0);
++		if ((value != 0xff) && (value != 0x00))
++			return 0;
++		udelay(REGISTER_BUSY_DELAY);
++	}
++
++	rt2x00_err(rt2x00dev, "BBP register access failed, aborting\n");
++	return -EACCES;
++}
++
+ static void rt2800_config_3572bt_ant(struct rt2x00_dev *rt2x00dev)
+ {
+ 	u32 reg;
+@@ -3799,10 +3841,9 @@ static void rt2800_config_alc(struct rt2
+ 			      struct ieee80211_channel *chan,
+ 			      int power_level) {
+ 	u16 eeprom, target_power, max_power;
+-	u32 mac_sys_ctrl, mac_status;
++	u32 mac_sys_ctrl;
+ 	u32 reg;
+ 	u8 bbp;
+-	int i;
+ 
+ 	/* hardware unit is 0.5dBm, limited to 23.5dBm */
+ 	power_level *= 2;
+@@ -3838,16 +3879,8 @@ static void rt2800_config_alc(struct rt2
+ 	/* Disable Tx/Rx */
+ 	rt2800_register_write(rt2x00dev, MAC_SYS_CTRL, 0);
+ 	/* Check MAC Tx/Rx idle */
+-	for (i = 0; i < 10000; i++) {
+-		mac_status = rt2800_register_read(rt2x00dev, MAC_STATUS_CFG);
+-		if (mac_status & 0x3)
+-			usleep_range(50, 200);
+-		else
+-			break;
+-	}
+-
+-	if (i == 10000)
+-		rt2x00_warn(rt2x00dev, "Wait MAC Status to MAX !!!\n");
++	if (unlikely(rt2800_wait_bbp_rf_ready(rt2x00dev, MAC_STATUS_CFG_BBP_RF_BUSY)))
++		rt2x00_warn(rt2x00dev, "RF busy while configuring ALC\n");
+ 
+ 	if (chan->center_freq > 2457) {
+ 		bbp = rt2800_bbp_read(rt2x00dev, 30);
+@@ -6249,46 +6282,6 @@ static int rt2800_init_registers(struct
+ 	return 0;
+ }
+ 
+-static int rt2800_wait_bbp_rf_ready(struct rt2x00_dev *rt2x00dev)
+-{
+-	unsigned int i;
+-	u32 reg;
+-
+-	for (i = 0; i < REGISTER_BUSY_COUNT; i++) {
+-		reg = rt2800_register_read(rt2x00dev, MAC_STATUS_CFG);
+-		if (!rt2x00_get_field32(reg, MAC_STATUS_CFG_BBP_RF_BUSY))
+-			return 0;
+-
+-		udelay(REGISTER_BUSY_DELAY);
+-	}
+-
+-	rt2x00_err(rt2x00dev, "BBP/RF register access failed, aborting\n");
+-	return -EACCES;
+-}
+-
+-static int rt2800_wait_bbp_ready(struct rt2x00_dev *rt2x00dev)
+-{
+-	unsigned int i;
+-	u8 value;
+-
+-	/*
+-	 * BBP was enabled after firmware was loaded,
+-	 * but we need to reactivate it now.
+-	 */
+-	rt2800_register_write(rt2x00dev, H2M_BBP_AGENT, 0);
+-	rt2800_register_write(rt2x00dev, H2M_MAILBOX_CSR, 0);
+-	msleep(1);
+-
+-	for (i = 0; i < REGISTER_BUSY_COUNT; i++) {
+-		value = rt2800_bbp_read(rt2x00dev, 0);
+-		if ((value != 0xff) && (value != 0x00))
+-			return 0;
+-		udelay(REGISTER_BUSY_DELAY);
+-	}
+-
+-	rt2x00_err(rt2x00dev, "BBP register access failed, aborting\n");
+-	return -EACCES;
+-}
+ 
+ static void rt2800_bbp4_mac_if_ctrl(struct rt2x00_dev *rt2x00dev)
+ {
+@@ -9110,7 +9103,7 @@ int rt2800_enable_radio(struct rt2x00_de
+ 	/*
+ 	 * Wait BBP/RF to wake up.
+ 	 */
+-	if (unlikely(rt2800_wait_bbp_rf_ready(rt2x00dev)))
++	if (unlikely(rt2800_wait_bbp_rf_ready(rt2x00dev, MAC_STATUS_CFG_BBP_RF_BUSY)))
+ 		return -EIO;
+ 
+ 	/*