[PATCH 2/2] Bluetooth: btmtksdio: retry enabling the function on MT7663/MT7668

[Ryan Brue]

Right after the Wi-Fi function of an MT7663 combo chip starts its
firmware, the WMT function-enable request is refused (the reply's flag
byte is 2). btmtksdio ignored the reply, so the following low power
setup command then timed out and setup failed:

  Bluetooth: hci0: command 0xfc7a tx timeout
  Bluetooth: hci0: Failed to apply low power setting (-110)

Check the result and retry every 500 ms, up to ten times, as MediaTek's
own driver retries its power-on command. With mt7663s probing first, the
function now starts on the second attempt and setup completes.

Fixes: 9aebfd4a2200 ("Bluetooth: mediatek: add support for MediaTek MT7663S and MT7668S SDIO devices")
Signed-off-by: Ryan Brue <ryanbrue.dev at gmail.com>
---
 drivers/bluetooth/btmtksdio.c | 28 ++++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)

diff --git a/drivers/bluetooth/btmtksdio.c b/drivers/bluetooth/btmtksdio.c
index bb311986271f..239393a15e46 100644
--- a/drivers/bluetooth/btmtksdio.c
+++ b/drivers/bluetooth/btmtksdio.c
@@ -909,17 +909,33 @@ static int mt76xx_setup(struct hci_dev *hdev, const char *fwname)
 		goto ignore_func_on;
 	}
 
-	/* Enable Bluetooth protocol */
+	/*
+	 * Enable Bluetooth protocol. While the Wi-Fi function of a combo
+	 * chip is still starting its firmware, the request is refused, so
+	 * retry it.
+	 */
 	wmt_params.op = BTMTK_WMT_FUNC_CTRL;
 	wmt_params.flag = 0;
 	wmt_params.dlen = sizeof(param);
 	wmt_params.data = ¶m;
-	wmt_params.status = NULL;
+	wmt_params.status = &status;
 
-	err = mtk_hci_wmt_sync(hdev, &wmt_params);
-	if (err < 0) {
-		bt_dev_err(hdev, "Failed to send wmt func ctrl (%d)", err);
-		return err;
+	for (i = 0; i < 10; i++) {
+		err = mtk_hci_wmt_sync(hdev, &wmt_params);
+		if (err < 0) {
+			bt_dev_err(hdev, "Failed to send wmt func ctrl (%d)",
+				   err);
+			return err;
+		}
+
+		if (status == BTMTK_WMT_ON_DONE)
+			break;
+		msleep(500);
+	}
+
+	if (status != BTMTK_WMT_ON_DONE) {
+		bt_dev_err(hdev, "Bluetooth function refused to start");
+		return -EIO;
 	}
 
 	set_bit(BTMTKSDIO_PATCH_ENABLED, &bdev->tx_state);

-- 
2.55.0