Bluetooth: mt7921s: fix firmware coredump retrieve

According to the MCU firmware behavior, as the driver is aware of the
notification of the interrupt source FW_MAILBOX_INT that shows the MCU
completed delivered a core dump piece to the host, the driver must
acknowledge the MCU with the register PH2DSM0R bit PH2DSM0R_DRIVER_OWN
to notify the MCU to handle the next core dump piece.

Fixes: db57b62 ("Bluetooth: btmtksdio: add support of processing firmware coredump and log")
Co-developed-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Mark Chen <mark-yw.chen@mediatek.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/btmtksdio.c

@@ -87,8 +87,12 @@ MODULE_DEVICE_TABLE(sdio, btmtksdio_table);
 #define RX_DONE_INT		BIT(1)
 #define TX_EMPTY		BIT(2)
 #define TX_FIFO_OVERFLOW	BIT(8)
+#define FW_MAILBOX_INT		BIT(15)
 #define RX_PKT_LEN		GENMASK(31, 16)
 
+#define MTK_REG_PH2DSM0R	0xc4
+#define PH2DSM0R_DRIVER_OWN	BIT(0)
+
 #define MTK_REG_CTDR		0x18
 
 #define MTK_REG_CRDR		0x1c
@@ -481,6 +485,12 @@ static void btmtksdio_txrx_work(struct work_struct *work)
 		 */
 		sdio_writel(bdev->func, int_status, MTK_REG_CHISR, NULL);
 
+		if ((int_status & FW_MAILBOX_INT) &&
+		    bdev->data->chipid == 0x7921) {
+			sdio_writel(bdev->func, PH2DSM0R_DRIVER_OWN,
+				    MTK_REG_PH2DSM0R, 0);
+		}
+
 		if (int_status & FW_OWN_BACK_INT)
 			bt_dev_dbg(bdev->hdev, "Get fw own back");