[PATCH 1/7] Bluetooth: add a quirk for controllers that cannot enable Secure Connections

[christian . koever-draxl]

From: Christian Stefan Kövér-Draxl <ckoever@xxxxxxxxxx>

The Amlogic W1 (W155S2) lists BR/EDR Secure Connections among its
extended features and then fails HCI_OP_WRITE_SC_SUPPORT with an error.
That failure is fatal to hci_dev_open_sync(), so the adapter can never
be powered on: every mgmt Set Powered returns Invalid Parameters and
bluetoothd gives up on the controller.

Add HCI_QUIRK_BROKEN_WRITE_SC_SUPPORT for controllers whose feature bit
cannot be taken at face value, skip the command in both places it is
issued, and set the quirk in hci_aml.

Signed-off-by: Christian Stefan Kövér-Draxl <ckoever@xxxxxxxxxx>
---
 drivers/bluetooth/hci_aml.c |  5 +++++
 include/net/bluetooth/hci.h | 14 ++++++++++++++
 net/bluetooth/hci_sync.c    |  8 ++++++--
 3 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/drivers/bluetooth/hci_aml.c b/drivers/bluetooth/hci_aml.c
index 067fbf278b44..990e701da4be 100644
--- a/drivers/bluetooth/hci_aml.c
+++ b/drivers/bluetooth/hci_aml.c
@@ -598,6 +598,11 @@ static int aml_setup(struct hci_uart *hu)
 	/* Setup bdaddr */
 	hdev->set_bdaddr = aml_set_bdaddr;
 
+	/* The controller lists BR/EDR Secure Connections among its extended
+	 * features and then rejects the command that turns host support on.
+	 */
+	hci_set_quirk(hdev, HCI_QUIRK_BROKEN_WRITE_SC_SUPPORT);
+
 	err = aml_power_on(amldev);
 	if (err)
 		return err;
diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index 1641d879dbda..bcbe76c84d1b 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -375,6 +375,20 @@ enum {
 	 */
 	HCI_QUIRK_BROKEN_READ_PAGE_SCAN_TYPE,
 
+	/*
+	 * When this quirk is set, the HCI_OP_WRITE_SC_SUPPORT command is
+	 * not supported.
+	 *
+	 * This quirk is intended for controllers that list BR/EDR Secure
+	 * Connections among their extended features and then reject the
+	 * command that turns host support on. Without it the failure takes
+	 * the whole of hci_dev_open_sync() with it and the controller can
+	 * never be powered on.
+	 *
+	 * This quirk must be set before hci_register_dev is called.
+	 */
+	HCI_QUIRK_BROKEN_WRITE_SC_SUPPORT,
+
 	__HCI_NUM_QUIRKS,
 };
 
diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index a92a81846e9d..f1dfef81ca96 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -3419,7 +3419,8 @@ int hci_write_sc_support_sync(struct hci_dev *hdev, u8 val)
 {
 	int err;
 
-	if (!bredr_sc_enabled(hdev) || lmp_host_sc_capable(hdev))
+	if (!bredr_sc_enabled(hdev) || lmp_host_sc_capable(hdev) ||
+	    hci_test_quirk(hdev, HCI_QUIRK_BROKEN_WRITE_SC_SUPPORT))
 		return 0;
 
 	err = __hci_cmd_sync_status(hdev, HCI_OP_WRITE_SC_SUPPORT,
@@ -5040,7 +5041,8 @@ static int hci_write_sc_support_1_sync(struct hci_dev *hdev)
 	u8 support = 0x01;
 
 	if (!hci_dev_test_flag(hdev, HCI_SSP_ENABLED) ||
-	    !bredr_sc_enabled(hdev))
+	    !bredr_sc_enabled(hdev) ||
+	    hci_test_quirk(hdev, HCI_QUIRK_BROKEN_WRITE_SC_SUPPORT))
 		return 0;
 
 	return __hci_cmd_sync_status(hdev, HCI_OP_WRITE_SC_SUPPORT,
@@ -5254,6 +5256,8 @@ static const struct {
 			 "HCI WRITE AUTH PAYLOAD TIMEOUT command leads "
 			 "to unexpected SMP errors when pairing "
 			 "and will not be used."),
+	HCI_QUIRK_BROKEN(WRITE_SC_SUPPORT,
+			 "HCI BR/EDR Secure Connections is advertised, but cannot be enabled."),
 	HCI_QUIRK_BROKEN(LE_CODED,
 			 "HCI LE Coded PHY feature bit is set, "
 			 "but its usage is not supported.")
-- 
2.56.0