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

From: Miao-chen Chou
Date: Thu Mar 26 2020 - 03:51:18 EST

On Wed, Mar 25, 2020 at 1:25 AM Marcel Holtmann <marcel@xxxxxxxxxxxx> wrote:
>
> Hi Miao-chen,
>
> > 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@xxxxxxxxxxxx>
> > ---
> >
> > 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;
>
> as noted in the other review, let hci_alloc_dev and hci_free_dev deal with this.
Will address this in v3.
>
> >
> > #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 */
>
> Lets put this all in net/bluetooth/msft.c for now.
Will address in v3.
>
> > 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);
>
> Are we really in interrupt context here? I donât think there is a need for GFP_ATOMIC.
Not really, will change this to GFP_KERNEL.
>
> > + if (!hdev->msft_ext.evt_prefix) {
> > + BT_WARN("%s: Microsoft extension invalid event prefix",
> > + hdev->name);
>
> Please start using bt_dev_warn etc.
Will address in v3.
>
> > + 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) {
>
> I really prefer it this way
>
> if (!something_supported)
> return;
Will address in v3.
>
> > + 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);
> > +
>
> msft_do_open(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;
> > +
>
> msft_do_close(hdev);
>
>
> And let these two function clear, init, free etc. everything except hdev->msft_ext.opcode
>
> That said, I would actually also introduce a wrapper msft_set_opcode(hdev, opcode); so that the driver doesnât have to know the internal on how that opcode is stored.
>
> We can also keep the struct msft_ext internal to msft.c and donât have to expose the internal details. So all stay confined in net/bluetooth/msft.c.
Good point. Will add net/bluetooth/msft.c in v3.
>
> > /* Avoid potential lockdep warnings from the *_flush() calls by
> > * ensuring the workqueue is empty up front.
> > */
Regards,
Miao