[PATCH v2 2/2] Bluetooth: btusb: Read the supported features of Microsoft vendor extension

[Miao-chen Chou <mcchou@chromium.org>]

This adds a new header to facilitate the opcode and packet structures of
vendor extension(s). For now, we add only the
HCI_VS_MSFT_Read_Supported_Features command from Microsoft vendor
extension. See https://docs.microsoft.com/en-us/windows-hardware/drivers/
bluetooth/microsoft-defined-bluetooth-hci-commands-and-events#
microsoft-defined-bluetooth-hci-events for more details.
Upon initialization of a hci_dev, we issue a
HCI_VS_MSFT_Read_Supported_Features command to read the supported features
of Microsoft vendor extension if the opcode of Microsoft vendor extension
is valid. See https://docs.microsoft.com/en-us/windows-hardware/drivers/
bluetooth/microsoft-defined-bluetooth-hci-commands-and-events#
hci_vs_msft_read_supported_features for more details.
This was verified on a device with Intel ThhunderPeak BT controller where
the Microsoft vendor extension features are 0x000000000000003f.

Signed-off-by: Miao-chen Chou <mcchou@chromium.org>
---

Changes in v2:
- Issue a HCI_VS_MSFT_Read_Supported_Features command with
__hci_cmd_sync() instead of constructing a request.

 drivers/bluetooth/btusb.c          |  3 ++
 include/net/bluetooth/hci_core.h   |  4 ++
 include/net/bluetooth/vendor_hci.h | 51 +++++++++++++++++++
 net/bluetooth/hci_core.c           | 78 ++++++++++++++++++++++++++++++
 4 files changed, 136 insertions(+)
 create mode 100644 include/net/bluetooth/vendor_hci.h

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 4c49f394f174..410d50dbd4e2 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -3738,6 +3738,9 @@ static int btusb_probe(struct usb_interface *intf,
 	hdev->notify = btusb_notify;
 
 	hdev->msft_ext.opcode = HCI_OP_NOP;
+	hdev->msft_ext.features = 0;
+	hdev->msft_ext.evt_prefix_len = 0;
+	hdev->msft_ext.evt_prefix = NULL;
 
 #ifdef CONFIG_PM
 	err = btusb_config_oob_wake(hdev);
diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index 0ec3d9b41d81..f2876c5067a4 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -30,6 +30,7 @@
 
 #include <net/bluetooth/hci.h>
 #include <net/bluetooth/hci_sock.h>
+#include <net/bluetooth/vendor_hci.h>
 
 /* HCI priority */
 #define HCI_PRIO_MAX	7
@@ -246,6 +247,9 @@ struct amp_assoc {
 
 struct msft_vnd_ext {
 	__u16	opcode;
+	__u64	features;
+	__u8	evt_prefix_len;
+	void	*evt_prefix;
 };
 
 struct hci_dev {
diff --git a/include/net/bluetooth/vendor_hci.h b/include/net/bluetooth/vendor_hci.h
new file mode 100644
index 000000000000..89a6795e672c
--- /dev/null
+++ b/include/net/bluetooth/vendor_hci.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * BlueZ - Bluetooth protocol stack for Linux
+ * Copyright (C) 2020 Google Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) AND AUTHOR(S) BE LIABLE FOR ANY
+ * CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PATENTS,
+ * COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS
+ * SOFTWARE IS DISCLAIMED.
+ */
+
+#ifndef __VENDOR_HCI_H
+#define __VENDOR_HCI_H
+
+#define MSFT_EVT_PREFIX_MAX_LEN			255
+
+struct msft_cmd_cmp_info {
+	__u8 status;
+	__u8 sub_opcode;
+} __packed;
+
+/* Microsoft Vendor HCI subcommands */
+#define MSFT_OP_READ_SUPPORTED_FEATURES		0x00
+#define MSFT_FEATURE_MASK_RSSI_MONITOR_BREDR_CONN	0x0000000000000001
+#define MSFT_FEATURE_MASK_RSSI_MONITOR_LE_CONN		0x0000000000000002
+#define MSFT_FEATURE_MASK_RSSI_MONITOR_LE_ADV		0x0000000000000004
+#define MSFT_FEATURE_MASK_ADV_MONITOR_LE_ADV		0x0000000000000008
+#define MSFT_FEATURE_MASK_VERIFY_CURVE			0x0000000000000010
+#define MSFT_FEATURE_MASK_CONCURRENT_ADV_MONITOR	0x0000000000000020
+struct msft_cp_read_supported_features {
+	__u8 sub_opcode;
+} __packed;
+struct msft_rp_read_supported_features {
+	__u64 features;
+	__u8  evt_prefix_len;
+	__u8  evt_prefix[0];
+} __packed;
+
+#endif /* __VENDOR_HCI_H */
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index dbd2ad3a26ed..1ea32d10ed08 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1407,6 +1407,76 @@ static void hci_dev_get_bd_addr_from_property(struct hci_dev *hdev)
 	bacpy(&hdev->public_addr, &ba);
 }
 
+static void process_msft_vnd_ext_cmd_complete(struct hci_dev *hdev,
+					      struct sk_buff *skb)
+{
+	struct msft_cmd_cmp_info *info = (void *)skb->data;
+	const u8 status = info->status;
+	const u16 sub_opcode = __le16_to_cpu(info->sub_opcode);
+
+	skb_pull(skb, sizeof(*info));
+
+	if (IS_ERR(skb)) {
+		BT_WARN("%s: Microsoft extension response packet invalid",
+			hdev->name);
+		return;
+	}
+
+	if (status) {
+		BT_WARN("%s: Microsoft extension sub command 0x%2.2x failed",
+			hdev->name, sub_opcode);
+		return;
+	}
+
+	BT_DBG("%s: status 0x%2.2x sub opcode 0x%2.2x", hdev->name, status,
+	       sub_opcode);
+
+	switch (sub_opcode) {
+	case MSFT_OP_READ_SUPPORTED_FEATURES: {
+		struct msft_rp_read_supported_features *rp = (void *)skb->data;
+		u8 prefix_len = rp->evt_prefix_len;
+
+		hdev->msft_ext.features = __le64_to_cpu(rp->features);
+		hdev->msft_ext.evt_prefix_len = prefix_len;
+		hdev->msft_ext.evt_prefix = kmalloc(prefix_len, GFP_ATOMIC);
+		if (!hdev->msft_ext.evt_prefix) {
+			BT_WARN("%s: Microsoft extension invalid event prefix",
+				hdev->name);
+			return;
+		}
+
+		memcpy(hdev->msft_ext.evt_prefix, rp->evt_prefix, prefix_len);
+		BT_INFO("%s: Microsoft extension features 0x%016llx",
+			hdev->name, hdev->msft_ext.features);
+		break;
+	}
+	default:
+		BT_WARN("%s: Microsoft extension unknown sub opcode 0x%2.2x",
+			hdev->name, sub_opcode);
+		break;
+	}
+}
+
+static void read_vendor_extension_features(struct hci_dev *hdev)
+{
+	struct sk_buff *skb;
+	const u16 msft_opcode = hdev->msft_ext.opcode;
+
+	if (msft_opcode !=  HCI_OP_NOP) {
+		struct msft_cp_read_supported_features cp;
+
+		cp.sub_opcode = MSFT_OP_READ_SUPPORTED_FEATURES;
+		skb = __hci_cmd_sync(hdev, msft_opcode, sizeof(cp), &cp,
+				     HCI_CMD_TIMEOUT);
+
+		process_msft_vnd_ext_cmd_complete(hdev, skb);
+		if (skb) {
+			kfree_skb(skb);
+			skb = NULL;
+		}
+	}
+}
+
 static int hci_dev_do_open(struct hci_dev *hdev)
 {
 	int ret = 0;
@@ -1554,6 +1624,11 @@ static int hci_dev_do_open(struct hci_dev *hdev)
 		}
 	}
 
+	/* Check features supported by HCI extensions after the init procedure
+	 * completed.
+	 */
+	read_vendor_extension_features(hdev);
+
 	/* If the HCI Reset command is clearing all diagnostic settings,
 	 * then they need to be reprogrammed after the init procedure
 	 * completed.
@@ -1733,6 +1808,9 @@ int hci_dev_do_close(struct hci_dev *hdev)
 			cancel_delayed_work_sync(&adv_instance->rpa_expired_cb);
 	}
 
+	kfree(hdev->msft_ext.evt_prefix);
+	hdev->msft_ext.evt_prefix = NULL;
+
 	/* Avoid potential lockdep warnings from the *_flush() calls by
 	 * ensuring the workqueue is empty up front.
 	 */
-- 
2.24.1