[PATCH v4 5/5] Bluetooth: btusb: mediatek: add MT7922 subsystem reset

[sean.wang at kernel.org]

From: Hao Qin <hao.qin at mediatek.com>

Add the support of MT7922 bluetooth subsystem reset that was called the
auto revert to self-recover from the fatal error in the controller like
the host encounters HCI cmd timeout or the controller crashes.

Co-developed-by: Sean Wang <sean.wang at mediatek.com>
Signed-off-by: Sean Wang <sean.wang at mediatek.com>
Signed-off-by: Hao Qin <hao.qin at mediatek.com>
---
v3: split from the v2 to make the patch do one thing in a patch.
v4: rebase onto the latest code
---
 drivers/bluetooth/btusb.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 054e8c06bcf3..a70a5e12912b 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -3039,7 +3039,16 @@ static int btusb_mtk_subsys_reset(struct hci_dev *hdev, u32 dev_id)
 	u32 val;
 	int err;
 
-	if (dev_id == 0x7925) {
+	if (dev_id == 0x7922) {
+		btusb_mtk_uhw_reg_read(data, MTK_BT_SUBSYS_RST, &val);
+		val |= 0x00002020;
+		btusb_mtk_uhw_reg_write(data, MTK_BT_SUBSYS_RST, val);
+		btusb_mtk_uhw_reg_write(data, MTK_EP_RST_OPT, 0x00010001);
+		btusb_mtk_uhw_reg_read(data, MTK_BT_SUBSYS_RST, &val);
+		val |= BIT(0);
+		btusb_mtk_uhw_reg_write(data, MTK_BT_SUBSYS_RST, val);
+		msleep(100);
+	} else if (dev_id == 0x7925) {
 		btusb_mtk_uhw_reg_read(data, MTK_BT_RESET_REG_CONNV3, &val);
 		val |= (1 << 5);
 		btusb_mtk_uhw_reg_write(data, MTK_BT_RESET_REG_CONNV3, val);
@@ -3079,6 +3088,9 @@ static int btusb_mtk_subsys_reset(struct hci_dev *hdev, u32 dev_id)
 	if (err < 0)
 		bt_dev_err(hdev, "Reset timeout");
 
+	if (dev_id == 0x7922)
+		btusb_mtk_uhw_reg_write(data, MTK_UDMA_INT_STA_BT, 0x000000FF);
+
 	btusb_mtk_id_get(data, 0x70010200, &val);
 	if (!val)
 		bt_dev_err(hdev, "Can't get device id, subsys reset fail.");
-- 
2.25.1