wifi: rtl8xxxu: Add beacon functions

Add a workqueue to update the beacon contents asynchronously and
implement downloading the beacon to the HW and starting beacon tx like
the vendor driver.
Signed-off-by: Martin Kaistra <martin.kaistra@linutronix.de>
Reviewed-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230428150833.218605-4-martin.kaistra@linutronix.de

drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h

@@ -1851,6 +1851,7 @@ struct rtl8xxxu_priv {
 	struct delayed_work ra_watchdog;
 	struct work_struct c2hcmd_work;
 	struct sk_buff_head c2hcmd_queue;
+	struct work_struct update_beacon_work;
 	struct rtl8xxxu_btcoex bt_coex;
 	struct rtl8xxxu_ra_report ra_report;
 	struct rtl8xxxu_cfo_tracking cfo_tracking;

drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c

@@ -1185,6 +1185,20 @@ static void rtl8xxxu_stop_tx_beacon(struct rtl8xxxu_priv *priv)
 	rtl8xxxu_write8(priv, REG_TBTT_PROHIBIT + 2, val8);
 }
 
+static void rtl8xxxu_start_tx_beacon(struct rtl8xxxu_priv *priv)
+{
+	u8 val8;
+
+	val8 = rtl8xxxu_read8(priv, REG_FWHW_TXQ_CTRL + 2);
+	val8 |= EN_BCNQ_DL >> 16;
+	rtl8xxxu_write8(priv, REG_FWHW_TXQ_CTRL + 2, val8);
+
+	rtl8xxxu_write8(priv, REG_TBTT_PROHIBIT + 1, 0x80);
+	val8 = rtl8xxxu_read8(priv, REG_TBTT_PROHIBIT + 2);
+	val8 &= 0xF0;
+	rtl8xxxu_write8(priv, REG_TBTT_PROHIBIT + 2, val8);
+}
+
 
 /*
  * The rtl8723a has 3 channel groups for it's efuse settings. It only
@@ -4964,6 +4978,17 @@ rtl8xxxu_bss_info_changed(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 		dev_dbg(dev, "Changed BASIC_RATES!\n");
 		rtl8xxxu_set_basic_rates(priv, bss_conf->basic_rates);
 	}
+
+	if (changed & BSS_CHANGED_BEACON_ENABLED) {
+		if (bss_conf->enable_beacon)
+			rtl8xxxu_start_tx_beacon(priv);
+		else
+			rtl8xxxu_stop_tx_beacon(priv);
+	}
+
+	if (changed & BSS_CHANGED_BEACON)
+		schedule_work(&priv->update_beacon_work);
+
 error:
 	return;
 }
@@ -5545,6 +5570,55 @@ static void rtl8xxxu_tx(struct ieee80211_hw *hw,
 	dev_kfree_skb(skb);
 }
 
+static void rtl8xxxu_send_beacon_frame(struct ieee80211_hw *hw,
+				       struct ieee80211_vif *vif)
+{
+	struct rtl8xxxu_priv *priv = hw->priv;
+	struct sk_buff *skb = ieee80211_beacon_get(hw, vif, 0);
+	struct device *dev = &priv->udev->dev;
+	int retry;
+	u8 val8;
+
+	/* BCN_VALID, write 1 to clear, cleared by SW */
+	val8 = rtl8xxxu_read8(priv, REG_TDECTRL + 2);
+	val8 |= BIT_BCN_VALID >> 16;
+	rtl8xxxu_write8(priv, REG_TDECTRL + 2, val8);
+
+	/* SW_BCN_SEL - Port0 */
+	val8 = rtl8xxxu_read8(priv, REG_DWBCN1_CTRL_8723B + 2);
+	val8 &= ~(BIT_SW_BCN_SEL >> 16);
+	rtl8xxxu_write8(priv, REG_DWBCN1_CTRL_8723B + 2, val8);
+
+	if (skb)
+		rtl8xxxu_tx(hw, NULL, skb);
+
+	retry = 100;
+	do {
+		val8 = rtl8xxxu_read8(priv, REG_TDECTRL + 2);
+		if (val8 & (BIT_BCN_VALID >> 16))
+			break;
+		usleep_range(10, 20);
+	} while (--retry);
+
+	if (!retry)
+		dev_err(dev, "%s: Failed to read beacon valid bit\n", __func__);
+}
+
+static void rtl8xxxu_update_beacon_work_callback(struct work_struct *work)
+{
+	struct rtl8xxxu_priv *priv =
+		container_of(work, struct rtl8xxxu_priv, update_beacon_work);
+	struct ieee80211_hw *hw = priv->hw;
+	struct ieee80211_vif *vif = priv->vif;
+
+	if (!vif) {
+		WARN_ONCE(true, "no vif to update beacon\n");
+		return;
+	}
+
+	rtl8xxxu_send_beacon_frame(hw, vif);
+}
+
 void rtl8723au_rx_parse_phystats(struct rtl8xxxu_priv *priv,
 				 struct ieee80211_rx_status *rx_status,
 				 struct rtl8723au_phy_stats *phy_stats,
@@ -7311,6 +7385,7 @@ static int rtl8xxxu_probe(struct usb_interface *interface,
 	spin_lock_init(&priv->rx_urb_lock);
 	INIT_WORK(&priv->rx_urb_wq, rtl8xxxu_rx_urb_work);
 	INIT_DELAYED_WORK(&priv->ra_watchdog, rtl8xxxu_watchdog_callback);
+	INIT_WORK(&priv->update_beacon_work, rtl8xxxu_update_beacon_work_callback);
 	skb_queue_head_init(&priv->c2hcmd_queue);
 
 	usb_set_intfdata(interface, hw);

drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_regs.h

@@ -456,6 +456,7 @@
 
 #define REG_FIFOPAGE			0x0204
 #define REG_TDECTRL			0x0208
+#define  BIT_BCN_VALID			BIT(16)
 
 #define REG_DWBCN0_CTRL_8188F		REG_TDECTRL
 
@@ -470,6 +471,7 @@
 #define  AUTO_LLT_INIT_LLT		BIT(16)
 
 #define REG_DWBCN1_CTRL_8723B		0x0228
+#define  BIT_SW_BCN_SEL			BIT(20)
 
 /* 0x0280 ~ 0x02FF	RXDMA Configuration */
 #define REG_RXDMA_AGG_PG_TH		0x0280	/* 0-7 : USB DMA size bits
@@ -516,6 +518,7 @@
 #define REG_FWHW_TXQ_CTRL		0x0420
 #define  FWHW_TXQ_CTRL_AMPDU_RETRY	BIT(7)
 #define  FWHW_TXQ_CTRL_XMIT_MGMT_ACK	BIT(12)
+#define  EN_BCNQ_DL			BIT(22)
 
 #define REG_HWSEQ_CTRL			0x0423
 #define REG_TXPKTBUF_BCNQ_BDNY		0x0424