[PATCH v2 2/2] rtw88: add debugfs to force lowest basic rate

[Ping-Ke Shih <pkshih@realtek.com>]

From: Yu-Yen Ting <steventing@realtek.com>

The management frame with high rate e.g. 24M may not be transmitted
smoothly in long range environment.
Add a debugfs to force to use the lowest basic rate
in order to debug the reachability of transmitting management frame.

obtain current setting
cat /sys/kernel/debug/ieee80211/phyX/rtw88/basic_rates

force lowest rate:
echo 1 > /sys/kernel/debug/ieee80211/phyX/rtw88/basic_rates

Signed-off-by: Yu-Yen Ting <steventing@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
---
 drivers/net/wireless/realtek/rtw88/debug.c | 39 ++++++++++++++++++++++
 drivers/net/wireless/realtek/rtw88/main.h  |  1 +
 drivers/net/wireless/realtek/rtw88/tx.c    |  3 +-
 3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/realtek/rtw88/debug.c b/drivers/net/wireless/realtek/rtw88/debug.c
index 18ab472ea46c..a99a3dc6f9f9 100644
--- a/drivers/net/wireless/realtek/rtw88/debug.c
+++ b/drivers/net/wireless/realtek/rtw88/debug.c
@@ -861,6 +861,39 @@ static int rtw_debugfs_get_fw_crash(struct seq_file *m, void *v)
 	return 0;
 }
 
+static ssize_t rtw_debugfs_set_basic_rates(struct file *filp,
+					   const char __user *buffer,
+					   size_t count, loff_t *loff)
+{
+	struct seq_file *seqpriv = (struct seq_file *)filp->private_data;
+	struct rtw_debugfs_priv *debugfs_priv = seqpriv->private;
+	struct rtw_dev *rtwdev = debugfs_priv->rtwdev;
+	bool input;
+	int err;
+
+	err = kstrtobool_from_user(buffer, count, &input);
+	if (err)
+		return err;
+
+	if (input)
+		set_bit(RTW_FLAG_USE_LOWEST_RATE, rtwdev->flags);
+	else
+		clear_bit(RTW_FLAG_USE_LOWEST_RATE, rtwdev->flags);
+
+	return count;
+}
+
+static int rtw_debugfs_get_basic_rates(struct seq_file *m, void *v)
+{
+	struct rtw_debugfs_priv *debugfs_priv = m->private;
+	struct rtw_dev *rtwdev = debugfs_priv->rtwdev;
+
+	seq_printf(m, "use lowest: %d\n",
+		   test_bit(RTW_FLAG_USE_LOWEST_RATE, rtwdev->flags));
+
+	return 0;
+}
+
 static ssize_t rtw_debugfs_set_dm_cap(struct file *filp,
 				      const char __user *buffer,
 				      size_t count, loff_t *loff)
@@ -1046,6 +1079,11 @@ static struct rtw_debugfs_priv rtw_debug_priv_fw_crash = {
 	.cb_read = rtw_debugfs_get_fw_crash,
 };
 
+static struct rtw_debugfs_priv rtw_debug_priv_basic_rates = {
+	.cb_write = rtw_debugfs_set_basic_rates,
+	.cb_read = rtw_debugfs_get_basic_rates,
+};
+
 static struct rtw_debugfs_priv rtw_debug_priv_dm_cap = {
 	.cb_write = rtw_debugfs_set_dm_cap,
 	.cb_read = rtw_debugfs_get_dm_cap,
@@ -1125,6 +1163,7 @@ void rtw_debugfs_init(struct rtw_dev *rtwdev)
 	rtw_debugfs_add_r(rf_dump);
 	rtw_debugfs_add_r(tx_pwr_tbl);
 	rtw_debugfs_add_rw(fw_crash);
+	rtw_debugfs_add_rw(basic_rates);
 	rtw_debugfs_add_rw(dm_cap);
 }
 
diff --git a/drivers/net/wireless/realtek/rtw88/main.h b/drivers/net/wireless/realtek/rtw88/main.h
index dc3744847ba9..0df5df3a62ab 100644
--- a/drivers/net/wireless/realtek/rtw88/main.h
+++ b/drivers/net/wireless/realtek/rtw88/main.h
@@ -362,6 +362,7 @@ enum rtw_flags {
 	RTW_FLAG_BUSY_TRAFFIC,
 	RTW_FLAG_WOWLAN,
 	RTW_FLAG_RESTARTING,
+	RTW_FLAG_USE_LOWEST_RATE,
 
 	NUM_OF_RTW_FLAGS,
 };
diff --git a/drivers/net/wireless/realtek/rtw88/tx.c b/drivers/net/wireless/realtek/rtw88/tx.c
index e5949a775283..0aeed15736c8 100644
--- a/drivers/net/wireless/realtek/rtw88/tx.c
+++ b/drivers/net/wireless/realtek/rtw88/tx.c
@@ -238,8 +238,9 @@ static u8 rtw_get_mgmt_rate(struct rtw_dev *rtwdev, struct sk_buff *skb,
 {
 	struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
 	struct ieee80211_vif *vif = tx_info->control.vif;
+	bool use_lowest = test_bit(RTW_FLAG_USE_LOWEST_RATE, rtwdev->flags);
 
-	if (!vif || !vif->bss_conf.basic_rates || ignore_rate)
+	if (!vif || !vif->bss_conf.basic_rates || ignore_rate || use_lowest)
 		return lowest_rate;
 
 	return __ffs(vif->bss_conf.basic_rates) + lowest_rate;
-- 
2.21.0