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Subject[PATCH v4 2/2] Bluetooth: btusb: Read the supported features of Microsoft vendor extension
Date
This defines opcode and packet structures of Microsoft vendor extension.
For now, we add only the HCI_VS_MSFT_Read_Supported_Features command. 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 ThunderPeak BT controller where
the Microsoft vendor extension features are 0x000000000000003f.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

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

Changes in v4:
- Move MSFT's do_open() and do_close() from net/bluetooth/hci_core.c to
net/bluetooth/msft.c.
- Other than msft opcode, define struct msft_data to host the rest of
information of Microsoft extension and leave a void* pointing to a
msft_data in struct hci_dev.

Changes in v3:
- Introduce msft_vnd_ext_do_open() and msft_vnd_ext_do_close().

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

include/net/bluetooth/hci_core.h | 1 +
net/bluetooth/hci_core.c | 5 ++
net/bluetooth/hci_event.c | 5 ++
net/bluetooth/msft.c | 126 +++++++++++++++++++++++++++++++
net/bluetooth/msft.h | 10 +++
5 files changed, 147 insertions(+)

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index 239cae2d9998..59ddcd3a52cc 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -486,6 +486,7 @@ struct hci_dev {

#if IS_ENABLED(CONFIG_BT_MSFTEXT)
__u16 msft_opcode;
+ void *msft_data;
#endif

int (*open)(struct hci_dev *hdev);
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index dbd2ad3a26ed..c38707de767a 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -44,6 +44,7 @@
#include "hci_debugfs.h"
#include "smp.h"
#include "leds.h"
+#include "msft.h"

static void hci_rx_work(struct work_struct *work);
static void hci_cmd_work(struct work_struct *work);
@@ -1563,6 +1564,8 @@ static int hci_dev_do_open(struct hci_dev *hdev)
hci_dev_test_flag(hdev, HCI_VENDOR_DIAG) && hdev->set_diag)
ret = hdev->set_diag(hdev, true);

+ msft_do_open(hdev);
+
clear_bit(HCI_INIT, &hdev->flags);

if (!ret) {
@@ -1758,6 +1761,8 @@ int hci_dev_do_close(struct hci_dev *hdev)

hci_sock_dev_event(hdev, HCI_DEV_DOWN);

+ msft_do_close(hdev);
+
if (hdev->flush)
hdev->flush(hdev);

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 20408d386268..42b5871151a6 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -35,6 +35,7 @@
#include "a2mp.h"
#include "amp.h"
#include "smp.h"
+#include "msft.h"

#define ZERO_KEY "\x00\x00\x00\x00\x00\x00\x00\x00" \
"\x00\x00\x00\x00\x00\x00\x00\x00"
@@ -6144,6 +6145,10 @@ void hci_event_packet(struct hci_dev *hdev, struct sk_buff *skb)
hci_num_comp_blocks_evt(hdev, skb);
break;

+ case HCI_EV_VENDOR:
+ msft_vendor_evt(hdev, skb);
+ break;
+
default:
BT_DBG("%s event 0x%2.2x", hdev->name, event);
break;
diff --git a/net/bluetooth/msft.c b/net/bluetooth/msft.c
index 7609932c48ca..f76e4c79556e 100644
--- a/net/bluetooth/msft.c
+++ b/net/bluetooth/msft.c
@@ -6,6 +6,24 @@

#include "msft.h"

+#define MSFT_OP_READ_SUPPORTED_FEATURES 0x00
+struct msft_cp_read_supported_features {
+ __u8 sub_opcode;
+} __packed;
+struct msft_rp_read_supported_features {
+ __u8 status;
+ __u8 sub_opcode;
+ __le64 features;
+ __u8 evt_prefix_len;
+ __u8 evt_prefix[0];
+} __packed;
+
+struct msft_data {
+ __u64 features;
+ __u8 evt_prefix_len;
+ __u8 *evt_prefix;
+};
+
void msft_set_opcode(struct hci_dev *hdev, __u16 opcode)
{
hdev->msft_opcode = opcode;
@@ -14,3 +32,111 @@ void msft_set_opcode(struct hci_dev *hdev, __u16 opcode)
hdev->msft_opcode);
}
EXPORT_SYMBOL(msft_set_opcode);
+
+static struct msft_data *read_supported_features(struct hci_dev *hdev)
+{
+ struct msft_data *msft;
+ struct msft_cp_read_supported_features cp;
+ struct msft_rp_read_supported_features *rp;
+ struct sk_buff *skb;
+
+ cp.sub_opcode = MSFT_OP_READ_SUPPORTED_FEATURES;
+
+ skb = __hci_cmd_sync(hdev, hdev->msft_opcode, sizeof(cp), &cp,
+ HCI_CMD_TIMEOUT);
+ if (IS_ERR(skb)) {
+ bt_dev_err(hdev, "Failed to read MSFT supported features (%ld)",
+ PTR_ERR(skb));
+ return NULL;
+ }
+
+ if (skb->len < sizeof(*rp)) {
+ bt_dev_err(hdev, "MSFT supported features length mismatch");
+ goto failed;
+ }
+
+ rp = (struct msft_rp_read_supported_features *)skb->data;
+
+ if (rp->sub_opcode != MSFT_OP_READ_SUPPORTED_FEATURES)
+ goto failed;
+
+ msft = kzalloc(sizeof(*msft), GFP_KERNEL);
+ if (!msft)
+ goto failed;
+
+ if (rp->evt_prefix_len > 0) {
+ msft->evt_prefix = kmemdup(rp->evt_prefix, rp->evt_prefix_len,
+ GFP_KERNEL);
+ if (!msft->evt_prefix)
+ goto failed;
+ }
+
+ msft->evt_prefix_len = rp->evt_prefix_len;
+ msft->features = __le64_to_cpu(rp->features);
+ kfree_skb(skb);
+
+ bt_dev_info(hdev, "MSFT supported features %llx", msft->features);
+ return msft;
+
+failed:
+ kfree_skb(skb);
+ return NULL;
+}
+
+void msft_do_open(struct hci_dev *hdev)
+{
+ if (hdev->msft_opcode == HCI_OP_NOP)
+ return;
+
+ bt_dev_dbg(hdev, "Initialize MSFT extension");
+ hdev->msft_data = read_supported_features(hdev);
+}
+
+void msft_do_close(struct hci_dev *hdev)
+{
+ struct msft_data *msft = hdev->msft_data;
+
+ if (!msft)
+ return;
+
+ bt_dev_dbg(hdev, "Cleanup of MSFT extension");
+
+ hdev->msft_data = NULL;
+
+ kfree(msft->evt_prefix);
+ kfree(msft);
+}
+
+int msft_vendor_evt(struct hci_dev *hdev, struct sk_buff *skb)
+{
+ struct msft_data *msft = hdev->msft_data;
+ u8 event;
+
+ if (!msft)
+ return -ENOSYS;
+
+ /* When the extension has defined an event prefix, check that it
+ * matches, and otherwise just return.
+ */
+ if (msft->evt_prefix_len > 0) {
+ if (skb->len < msft->evt_prefix_len)
+ return -ENOSYS;
+
+ if (memcmp(skb->data, msft->evt_prefix, msft->evt_prefix_len))
+ return -ENOSYS;
+
+ skb_pull(skb, msft->evt_prefix_len);
+ }
+
+ /* Every event starts at least with an event code and the rest of
+ * the data is variable and depends on the event code. Returns true
+ */
+ if (skb->len < 1)
+ return -EBADMSG;
+
+ event = *skb->data;
+ skb_pull(skb, 1);
+
+ bt_dev_dbg(hdev, "MSFT vendor event %u", event);
+ return 0;
+}
diff --git a/net/bluetooth/msft.h b/net/bluetooth/msft.h
index 7218ea759dde..6a7d0ac6c66c 100644
--- a/net/bluetooth/msft.h
+++ b/net/bluetooth/msft.h
@@ -4,15 +4,25 @@
#ifndef __MSFT_H
#define __MSFT_H

+#include <linux/errno.h>
#include <net/bluetooth/hci_core.h>

#if IS_ENABLED(CONFIG_BT_MSFTEXT)

void msft_set_opcode(struct hci_dev *hdev, __u16 opcode);
+void msft_do_open(struct hci_dev *hdev);
+void msft_do_close(struct hci_dev *hdev);
+int msft_vendor_evt(struct hci_dev *hdev, struct sk_buff *skb);

#else

static inline void msft_set_opcode(struct hci_dev *hdev, __u16 opcode) {}
+static inline void msft_do_open(struct hci_dev *hdev) {}
+static inline void msft_do_close(struct hci_dev *hdev) {}
+static inline int msft_vendor_evt(struct hci_dev *hdev, struct sk_buff *skb)
+{
+ return -ENOSYS;
+}

#endif

--
2.24.1
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