Bluetooth: btmtksdio: transmit packet according to status TX_EMPTY

Each packet should be sent out until the device emits the TX_EMPTY signal
to the host, that is firmware people suggested to add to meet the actual
firmware behavior and that is compatible among all the devices.

Co-developed-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Mark-yw Chen <mark-yw.chen@mediatek.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/btmtksdio.c

@@ -103,6 +103,7 @@ struct btmtksdio_dev {
 	struct work_struct txrx_work;
 	unsigned long tx_state;
 	struct sk_buff_head txq;
+	bool hw_tx_ready;
 
 	struct sk_buff *evt_skb;
 
@@ -229,6 +230,7 @@ static int btmtksdio_tx_packet(struct btmtksdio_dev *bdev,
 	sdio_hdr->reserved = cpu_to_le16(0);
 	sdio_hdr->bt_type = hci_skb_pkt_type(skb);
 
+	bdev->hw_tx_ready = false;
 	err = sdio_writesb(bdev->func, MTK_REG_CTDR, skb->data,
 			   round_up(skb->len, MTK_SDIO_BLOCK_SIZE));
 	if (err < 0)
@@ -417,15 +419,6 @@ static void btmtksdio_txrx_work(struct work_struct *work)
 	/* Disable interrupt */
 	sdio_writel(bdev->func, C_INT_EN_CLR, MTK_REG_CHLPCR, 0);
 
-	while ((skb = skb_dequeue(&bdev->txq))) {
-		err = btmtksdio_tx_packet(bdev, skb);
-		if (err < 0) {
-			bdev->hdev->stat.err_tx++;
-			skb_queue_head(&bdev->txq, skb);
-			break;
-		}
-	}
-
 	txrx_timeout = jiffies + 5 * HZ;
 
 	do {
@@ -446,10 +439,21 @@ static void btmtksdio_txrx_work(struct work_struct *work)
 			bt_dev_dbg(bdev->hdev, "Get fw own back");
 
 		if (int_status & TX_EMPTY)
-			schedule_work(&bdev->txrx_work);
+			bdev->hw_tx_ready = true;
 		else if (unlikely(int_status & TX_FIFO_OVERFLOW))
 			bt_dev_warn(bdev->hdev, "Tx fifo overflow");
 
+		if (bdev->hw_tx_ready) {
+			skb = skb_dequeue(&bdev->txq);
+			if (skb) {
+				err = btmtksdio_tx_packet(bdev, skb);
+				if (err < 0) {
+					bdev->hdev->stat.err_tx++;
+					skb_queue_head(&bdev->txq, skb);
+				}
+			}
+		}
+
 		if (int_status & RX_DONE_INT) {
 			rx_size = sdio_readl(bdev->func, MTK_REG_CRPLR, NULL);
 			rx_size = (rx_size & RX_PKT_LEN) >> 16;
@@ -642,6 +646,7 @@ static int btmtksdio_setup(struct hci_dev *hdev)
 	u8 param = 0x1;
 
 	calltime = ktime_get();
+	bdev->hw_tx_ready = true;
 
 	/* Query whether the firmware is already download */
 	wmt_params.op = BTMTK_WMT_SEMAPHORE;