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From:   Tedd Ho-Jeong An <hj.tedd.an@gmail.com>
To:     linux-bluetooth@vger.kernel.org
Cc:     Tedd Ho-Jeong An <tedd.an@intel.com>
Subject: [RFC PATCH V2] Bluetooth: vhci: Add support extended opcode for HCI Vendor packet
Date:   Mon,  1 Nov 2021 19:56:23 -0700
Message-Id: <20211102025623.826277-1-hj.tedd.an@gmail.com>
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From: Tedd Ho-Jeong An <tedd.an@intel.com>

Current implementation uses the Vendor packet type (0xff) with opcode
parameter. But there is no way to expand the opcode and no available bits
to use. Also it cannot be changed due to the backward compatibility
with older kernel.

THis patch adds new opcode(0x03) for HCI Vendor packet for VHCI for
extended device creation. This new opcode will not conflict with
existing legacy opcode because the legacy expects to set either bit 0 or
bit 1, but not both of bits.

It aslo requires new extra parameters for device type and flags to apply
to the VHCI device.

Signed-off-by: Tedd Ho-Jeong An <tedd.an@intel.com>
---
 drivers/bluetooth/hci_vhci.c | 65 ++++++++++++++++++++++++++++++++----
 1 file changed, 58 insertions(+), 7 deletions(-)

diff --git a/drivers/bluetooth/hci_vhci.c b/drivers/bluetooth/hci_vhci.c
index 49ac884d996e..5fccab136543 100644
--- a/drivers/bluetooth/hci_vhci.c
+++ b/drivers/bluetooth/hci_vhci.c
@@ -30,6 +30,16 @@
 
 static bool amp;
 
+#define VHCI_EXT_OPCODE				0x03
+struct vhci_ext_config {
+	__u8  dev_type;
+	__u32 flags;
+} __packed;
+
+#define VHCI_FLAG_QUIRK_RAW_DEVICE		0x01
+#define VHCI_FLAG_QUIRK_EXTERNAL_CONFIG		0x02
+#define VHCI_FLAG_QUIRKS_INVALID_BDADDR		0x04
+
 struct vhci_data {
 	struct hci_dev *hdev;
 
@@ -278,7 +288,8 @@ static int vhci_setup(struct hci_dev *hdev)
 	return 0;
 }
 
-static int __vhci_create_device(struct vhci_data *data, __u8 opcode)
+static int __vhci_create_device(struct vhci_data *data, __u8 opcode,
+				struct vhci_ext_config *ext_config)
 {
 	struct hci_dev *hdev;
 	struct sk_buff *skb;
@@ -287,8 +298,20 @@ static int __vhci_create_device(struct vhci_data *data, __u8 opcode)
 	if (data->hdev)
 		return -EBADFD;
 
-	/* bits 0-1 are dev_type (Primary or AMP) */
-	dev_type = opcode & 0x03;
+	/* In case of legacy opcode, it doesn't allow to have 0x03 as an opcode,
+	 * So, it is ok to assume that device is in the extended device
+	 * creation mode when the opcode is 0x03. Also, it is required to have
+	 * a ext_config and check it here.
+	 */
+	if (ext_config && opcode != VHCI_EXT_OPCODE)
+		return -EINVAL;
+
+	if (opcode == VHCI_EXT_OPCODE)
+		dev_type = ext_config->dev_type;
+	else {
+		/* bits 0-1 are dev_type (Primary or AMP) */
+		dev_type = opcode & 0x03;
+	}
 
 	if (dev_type != HCI_PRIMARY && dev_type != HCI_AMP)
 		return -EINVAL;
@@ -331,6 +354,16 @@ static int __vhci_create_device(struct vhci_data *data, __u8 opcode)
 	if (opcode & 0x80)
 		set_bit(HCI_QUIRK_RAW_DEVICE, &hdev->quirks);
 
+	/* Flags for extended configuration */
+	if (ext_config && opcode == VHCI_EXT_OPCODE) {
+		if (ext_config->flags & VHCI_FLAG_QUIRK_EXTERNAL_CONFIG)
+			set_bit(HCI_QUIRK_EXTERNAL_CONFIG, &hdev->quirks);
+		if (ext_config->flags & VHCI_FLAG_QUIRK_RAW_DEVICE)
+			set_bit(HCI_QUIRK_RAW_DEVICE, &hdev->quirks);
+		if (ext_config->flags & VHCI_FLAG_QUIRKS_INVALID_BDADDR)
+			set_bit(HCI_QUIRK_INVALID_BDADDR, &hdev->quirks);
+	}
+
 	if (hci_register_dev(hdev) < 0) {
 		BT_ERR("Can't register HCI device");
 		hci_free_dev(hdev);
@@ -364,12 +397,13 @@ static int __vhci_create_device(struct vhci_data *data, __u8 opcode)
 	return 0;
 }
 
-static int vhci_create_device(struct vhci_data *data, __u8 opcode)
+static int vhci_create_device(struct vhci_data *data, __u8 opcode,
+			      struct vhci_ext_config *ext_config)
 {
 	int err;
 
 	mutex_lock(&data->open_mutex);
-	err = __vhci_create_device(data, opcode);
+	err = __vhci_create_device(data, opcode, ext_config);
 	mutex_unlock(&data->open_mutex);
 
 	return err;
@@ -379,6 +413,7 @@ static inline ssize_t vhci_get_user(struct vhci_data *data,
 				    struct iov_iter *from)
 {
 	size_t len = iov_iter_count(from);
+	struct vhci_ext_config *ext_config;
 	struct sk_buff *skb;
 	__u8 pkt_type, opcode;
 	int ret;
@@ -419,6 +454,21 @@ static inline ssize_t vhci_get_user(struct vhci_data *data,
 		opcode = *((__u8 *) skb->data);
 		skb_pull(skb, 1);
 
+		/* This opcode(0x03) is for extended device creation and it
+		 * requires the extra parameters for extra configuration.
+		 */
+		if (opcode == 0x03) {
+			if (skb->len != sizeof(*ext_config)) {
+				kfree_skb(skb);
+				return -EINVAL;
+			}
+
+			ext_config = (void *) (skb->data);
+			ret = vhci_create_device(data, opcode, ext_config);
+			kfree_skb(skb);
+			goto done;
+		}
+
 		if (skb->len > 0) {
 			kfree_skb(skb);
 			return -EINVAL;
@@ -426,7 +476,7 @@ static inline ssize_t vhci_get_user(struct vhci_data *data,
 
 		kfree_skb(skb);
 
-		ret = vhci_create_device(data, opcode);
+		ret = vhci_create_device(data, opcode, NULL);
 		break;
 
 	default:
@@ -434,6 +484,7 @@ static inline ssize_t vhci_get_user(struct vhci_data *data,
 		return -EINVAL;
 	}
 
+done:
 	return (ret < 0) ? ret : len;
 }
 
@@ -526,7 +577,7 @@ static void vhci_open_timeout(struct work_struct *work)
 	struct vhci_data *data = container_of(work, struct vhci_data,
 					      open_timeout.work);
 
-	vhci_create_device(data, amp ? HCI_AMP : HCI_PRIMARY);
+	vhci_create_device(data, amp ? HCI_AMP : HCI_PRIMARY, NULL);
 }
 
 static int vhci_open(struct inode *inode, struct file *file)
-- 
2.25.1