Bluetooth: btintel: Add support to reset bluetooth via ACPI DSM

New Intel platforms supports reset of Bluetooth device  via ACPI DSM
methods. The legacy reset mechanism via GPIO will be deprecated in
future. This patch checks the platform support for reset methods and if
supported uses the same instead of legacy GPIO toggling method.

ACPI firmware supports two types of reset method based on NIC card.
(Discrete or Integrated).

1. VSEC Type - Vendor Specific Extended Capability. Here  BT_EN and
   BT_IF_SELECT lines are driven by a register in PCH cluster. This
   interface is supported on discrete BT solution.

2. WDISABLE2 - In this soluton, W_DISABLE2 pin in M.2 is connected to
   physical GPIO from PCH. The DSM interface shall toggle this to recover
   from  error.
Signed-off-by: Kiran K <kiran.k@intel.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

drivers/bluetooth/btintel.c

@@ -10,6 +10,7 @@
 #include <linux/firmware.h>
 #include <linux/regmap.h>
 #include <linux/acpi.h>
+#include <acpi/acpi_bus.h>
 #include <asm/unaligned.h>
 
 #include <net/bluetooth/bluetooth.h>
@@ -27,6 +28,11 @@
 
 #define BTINTEL_PPAG_NAME   "PPAG"
 
+enum {
+	DSM_SET_WDISABLE2_DELAY = 1,
+	DSM_SET_RESET_METHOD = 3,
+};
+
 /* structure to store the PPAG data read from ACPI table */
 struct btintel_ppag {
 	u32	domain;
@@ -49,6 +55,10 @@ static struct {
 	u32        fw_build_num;
 } coredump_info;
 
+static const guid_t btintel_guid_dsm =
+	GUID_INIT(0xaa10f4e0, 0x81ac, 0x4233,
+		  0xab, 0xf6, 0x3b, 0x2a, 0xc5, 0x0e, 0x28, 0xd9);
+
 int btintel_check_bdaddr(struct hci_dev *hdev)
 {
 	struct hci_rp_read_bd_addr *bda;
@@ -2444,6 +2454,116 @@ static void btintel_set_ppag(struct hci_dev *hdev, struct intel_version_tlv *ver
 	kfree_skb(skb);
 }
 
+static int btintel_acpi_reset_method(struct hci_dev *hdev)
+{
+	int ret = 0;
+	acpi_status status;
+	union acpi_object *p, *ref;
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+
+	status = acpi_evaluate_object(ACPI_HANDLE(GET_HCIDEV_DEV(hdev)), "_PRR", NULL, &buffer);
+	if (ACPI_FAILURE(status)) {
+		bt_dev_err(hdev, "Failed to run _PRR method");
+		ret = -ENODEV;
+		return ret;
+	}
+	p = buffer.pointer;
+
+	if (p->package.count != 1 || p->type != ACPI_TYPE_PACKAGE) {
+		bt_dev_err(hdev, "Invalid arguments");
+		ret = -EINVAL;
+		goto exit_on_error;
+	}
+
+	ref = &p->package.elements[0];
+	if (ref->type != ACPI_TYPE_LOCAL_REFERENCE) {
+		bt_dev_err(hdev, "Invalid object type: 0x%x", ref->type);
+		ret = -EINVAL;
+		goto exit_on_error;
+	}
+
+	status = acpi_evaluate_object(ref->reference.handle, "_RST", NULL, NULL);
+	if (ACPI_FAILURE(status)) {
+		bt_dev_err(hdev, "Failed to run_RST method");
+		ret = -ENODEV;
+		goto exit_on_error;
+	}
+
+exit_on_error:
+	kfree(buffer.pointer);
+	return ret;
+}
+
+static void btintel_set_dsm_reset_method(struct hci_dev *hdev,
+					 struct intel_version_tlv *ver_tlv)
+{
+	struct btintel_data *data = hci_get_priv(hdev);
+	acpi_handle handle = ACPI_HANDLE(GET_HCIDEV_DEV(hdev));
+	u8 reset_payload[4] = {0x01, 0x00, 0x01, 0x00};
+	union acpi_object *obj, argv4;
+	enum {
+		RESET_TYPE_WDISABLE2,
+		RESET_TYPE_VSEC
+	};
+
+	handle = ACPI_HANDLE(GET_HCIDEV_DEV(hdev));
+
+	if (!handle) {
+		bt_dev_dbg(hdev, "No support for bluetooth device in ACPI firmware");
+		return;
+	}
+
+	if (!acpi_has_method(handle, "_PRR")) {
+		bt_dev_err(hdev, "No support for _PRR ACPI method");
+		return;
+	}
+
+	switch (ver_tlv->cnvi_top & 0xfff) {
+	case 0x910: /* GalePeak2 */
+		reset_payload[2] = RESET_TYPE_VSEC;
+		break;
+	default:
+		/* WDISABLE2 is the default reset method */
+		reset_payload[2] = RESET_TYPE_WDISABLE2;
+
+		if (!acpi_check_dsm(handle, &btintel_guid_dsm, 0,
+				    BIT(DSM_SET_WDISABLE2_DELAY))) {
+			bt_dev_err(hdev, "No dsm support to set reset delay");
+			return;
+		}
+		argv4.integer.type = ACPI_TYPE_INTEGER;
+		/* delay required to toggle BT power */
+		argv4.integer.value = 160;
+		obj = acpi_evaluate_dsm(handle, &btintel_guid_dsm, 0,
+					DSM_SET_WDISABLE2_DELAY, &argv4);
+		if (!obj) {
+			bt_dev_err(hdev, "Failed to call dsm to set reset delay");
+			return;
+		}
+		ACPI_FREE(obj);
+	}
+
+	bt_dev_info(hdev, "DSM reset method type: 0x%02x", reset_payload[2]);
+
+	if (!acpi_check_dsm(handle, &btintel_guid_dsm, 0,
+			    DSM_SET_RESET_METHOD)) {
+		bt_dev_warn(hdev, "No support for dsm to set reset method");
+		return;
+	}
+	argv4.buffer.type = ACPI_TYPE_BUFFER;
+	argv4.buffer.length = sizeof(reset_payload);
+	argv4.buffer.pointer = reset_payload;
+
+	obj = acpi_evaluate_dsm(handle, &btintel_guid_dsm, 0,
+				DSM_SET_RESET_METHOD, &argv4);
+	if (!obj) {
+		bt_dev_err(hdev, "Failed to call dsm to set reset method");
+		return;
+	}
+	ACPI_FREE(obj);
+	data->acpi_reset_method = btintel_acpi_reset_method;
+}
+
 static int btintel_bootloader_setup_tlv(struct hci_dev *hdev,
 					struct intel_version_tlv *ver)
 {
@@ -2757,6 +2877,7 @@ static int btintel_setup_combined(struct hci_dev *hdev)
 		/* Setup MSFT Extension support */
 		btintel_set_msft_opcode(hdev,
 					INTEL_HW_VARIANT(ver_tlv.cnvi_bt));
+		btintel_set_dsm_reset_method(hdev, &ver_tlv);
 
 		err = btintel_bootloader_setup_tlv(hdev, &ver_tlv);
 		btintel_register_devcoredump_support(hdev);

drivers/bluetooth/btintel.h

@@ -166,12 +166,14 @@ enum {
 	INTEL_BROKEN_SHUTDOWN_LED,
 	INTEL_ROM_LEGACY,
 	INTEL_ROM_LEGACY_NO_WBS_SUPPORT,
+	INTEL_ACPI_RESET_ACTIVE,
 
 	__INTEL_NUM_FLAGS,
 };
 
 struct btintel_data {
 	DECLARE_BITMAP(flags, __INTEL_NUM_FLAGS);
+	int (*acpi_reset_method)(struct hci_dev *hdev);
 };
 
 #define btintel_set_flag(hdev, nr)					\

drivers/bluetooth/btusb.c

@@ -860,10 +860,26 @@ static void btusb_intel_cmd_timeout(struct hci_dev *hdev)
 {
 	struct btusb_data *data = hci_get_drvdata(hdev);
 	struct gpio_desc *reset_gpio = data->reset_gpio;
+	struct btintel_data *intel_data = hci_get_priv(hdev);
 
 	if (++data->cmd_timeout_cnt < 5)
 		return;
 
+	if (intel_data->acpi_reset_method) {
+		if (test_and_set_bit(INTEL_ACPI_RESET_ACTIVE, intel_data->flags)) {
+			bt_dev_err(hdev, "acpi: last reset failed ? Not resetting again");
+			return;
+		}
+
+		bt_dev_err(hdev, "Initiating acpi reset method");
+		/* If ACPI reset method fails, lets try with legacy GPIO
+		 * toggling
+		 */
+		if (!intel_data->acpi_reset_method(hdev)) {
+			return;
+		}
+	}
+
 	if (!reset_gpio) {
 		btusb_reset(hdev);
 		return;