[PATCH v5 1/3] Bluetooth: Add the framework of using Microsoft vendor extension

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

This adds the framework of using Microsoft vendor extension by
introducing a kernel config, BT_MSFTEXT, and a source file to facilitate
Microsoft vendor extension functions.
This was verified with Intel ThunderPeak BT controller
where msft_opcode is 0xFC1E. See https://docs.microsoft.com/en-us/windows-
hardware/drivers/bluetooth/microsoft-defined-bluetooth-hci-commands-and-
events for more information about the extension.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
(cherry picked from commit dadae5cfbf84abb7b5465e82a7aae801a2a4f163)
Signed-off-by: Miao-chen Chou <mcchou@chromium.org>
---

Changes in v5:
- Extract the changes on btusb as a different commit.

Changes in v4:
- Introduce CONFIG_BT_MSFTEXT as a starting point of providing a
framework to use Microsoft extension
- Create include/net/bluetooth/msft.h and net/bluetooth/msft.c to
facilitate functions of Microsoft extension.

Changes in v3:
- Create net/bluetooth/msft.c with struct msft_vnd_ext defined internally
and change the hdev->msft_ext field to void*.
- Define and expose msft_vnd_ext_set_opcode() for btusb use.
- Init hdev->msft_ext in hci_alloc_dev() and deinit it in hci_free_dev().

Changes in v2:
- Define struct msft_vnd_ext and add a field of this type to struct
hci_dev to facilitate the support of Microsoft vendor extension.

 include/net/bluetooth/hci_core.h |  4 ++++
 include/net/bluetooth/msft.h     | 19 +++++++++++++++++++
 net/bluetooth/Kconfig            |  7 +++++++
 net/bluetooth/Makefile           |  1 +
 net/bluetooth/msft.c             | 15 +++++++++++++++
 5 files changed, 46 insertions(+)
 create mode 100644 include/net/bluetooth/msft.h
 create mode 100644 net/bluetooth/msft.c

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index d4e28773d3781..239cae2d99986 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -484,6 +484,10 @@ struct hci_dev {
 	struct led_trigger	*power_led;
 #endif
 
+#if IS_ENABLED(CONFIG_BT_MSFTEXT)
+	__u16			msft_opcode;
+#endif
+
 	int (*open)(struct hci_dev *hdev);
 	int (*close)(struct hci_dev *hdev);
 	int (*flush)(struct hci_dev *hdev);
diff --git a/include/net/bluetooth/msft.h b/include/net/bluetooth/msft.h
new file mode 100644
index 0000000000000..7218ea759dde4
--- /dev/null
+++ b/include/net/bluetooth/msft.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Copyright (C) 2020 Google Corporation */
+
+#ifndef __MSFT_H
+#define __MSFT_H
+
+#include <net/bluetooth/hci_core.h>
+
+#if IS_ENABLED(CONFIG_BT_MSFTEXT)
+
+void msft_set_opcode(struct hci_dev *hdev, __u16 opcode);
+
+#else
+
+static inline void msft_set_opcode(struct hci_dev *hdev, __u16 opcode) {}
+
+#endif
+
+#endif /* __MSFT_H*/
diff --git a/net/bluetooth/Kconfig b/net/bluetooth/Kconfig
index 165148c7c4ce5..d439be5c534e7 100644
--- a/net/bluetooth/Kconfig
+++ b/net/bluetooth/Kconfig
@@ -93,6 +93,13 @@ config BT_LEDS
 	  This option selects a few LED triggers for different
 	  Bluetooth events.
 
+config BT_MSFTEXT
+	bool "Enable Microsoft extensions"
+	depends on BT
+	help
+	  This options enables support for the Microsoft defined HCI
+	  vendor extensions.
+
 config BT_SELFTEST
 	bool "Bluetooth self testing support"
 	depends on BT && DEBUG_KERNEL
diff --git a/net/bluetooth/Makefile b/net/bluetooth/Makefile
index fda41c0b47818..41dd541a44a52 100644
--- a/net/bluetooth/Makefile
+++ b/net/bluetooth/Makefile
@@ -19,5 +19,6 @@ bluetooth-y := af_bluetooth.o hci_core.o hci_conn.o hci_event.o mgmt.o \
 bluetooth-$(CONFIG_BT_BREDR) += sco.o
 bluetooth-$(CONFIG_BT_HS) += a2mp.o amp.o
 bluetooth-$(CONFIG_BT_LEDS) += leds.o
+bluetooth-$(CONFIG_BT_MSFTEXT) += msft.o
 bluetooth-$(CONFIG_BT_DEBUGFS) += hci_debugfs.o
 bluetooth-$(CONFIG_BT_SELFTEST) += selftest.o
diff --git a/net/bluetooth/msft.c b/net/bluetooth/msft.c
new file mode 100644
index 0000000000000..04dad4ac7bf78
--- /dev/null
+++ b/net/bluetooth/msft.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Copyright (C) 2020 Google Corporation */
+
+#include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci_core.h>
+#include <net/bluetooth/msft.h>
+
+void msft_set_opcode(struct hci_dev *hdev, __u16 opcode)
+{
+	hdev->msft_opcode = opcode;
+
+	bt_dev_info(hdev, "Enabling MSFT extensions with opcode 0x%2.2x",
+		    hdev->msft_opcode);
+}
+EXPORT_SYMBOL(msft_set_opcode);
-- 
2.24.1