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From:   Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Date:   Wed, 13 Jan 2021 15:51:25 -0800
Message-ID: <CABBYNZ+vTRiZ4ayEO=2bn+tqztwnL_L3=o9NPPKs7vQicC6rkg@mail.gmail.com>
Subject: Re: [RESEND 1/2] Bluetooth: btusb: Add support for queuing during
 polling interval
To:     Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Cc:     Archie Pusaka <apusaka@chromium.org>,
        Alain Michaud <alainmichaud@google.com>,
        Bluez mailing list <linux-bluetooth@vger.kernel.org>
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Precedence: bulk

Hi Abhishek,

On Wed, Jan 13, 2021 at 3:48 PM Abhishek Pandit-Subedi
<abhishekpandit@chromium.org> wrote:
>
> + Archie, Alain
>
> It looks like we already landed this change into Chrome a while ago
> and we haven't had any issues.
> https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/2312116

Good to know, but can you also confirm it is running with
CONFIG_BT_HCIBTUSB_INTERVAL=y?

> Archie, can you confirm that this is the case?
>
> Thanks
> Abhishek
>
> On Wed, Jan 13, 2021 at 3:33 PM Luiz Augusto von Dentz
> <luiz.dentz@gmail.com> wrote:
> >
> > Hi Abhishek,
> >
> > On Wed, Jan 13, 2021 at 3:28 PM Luiz Augusto von Dentz
> > <luiz.dentz@gmail.com> wrote:
> > >
> > > From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
> > >
> > > This makes btusb to queue ACL and events during a polling interval
> > > by using of a delayed work, with the interval working as a time window
> > > where frames received from different endpoints are considered to be
> > > arrived at same time and then attempt to resolve potential conflics by
> > > processing the events ahead of ACL packets.
> > >
> > > It worth noting though that priorizing events over ACL data may result
> > > in inverting the order compared to how they appeared over the air, for
> > > instance there may be packets received before a disconnect event that
> > > will be discarded and unencrypted packets received before encryption
> > > change which would considered encrypted, because of these potential
> > > changes on the order the support for queuing during the polling
> > > interval is not enabled by default so platforms have the following
> > > means to enable it:
> > >
> > > At build-time:
> > >
> > >     CONFIG_BT_HCIBTUSB_INTERVAL=y
> > >
> > > At runtime with use of module option:
> > >
> > >     enable_interval
> > >
> > > Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
> > > ---
> > >  drivers/bluetooth/Kconfig |  7 ++++
> > >  drivers/bluetooth/btusb.c | 88 ++++++++++++++++++++++++++++++++++-----
> > >  2 files changed, 84 insertions(+), 11 deletions(-)
> > >
> > > diff --git a/drivers/bluetooth/Kconfig b/drivers/bluetooth/Kconfig
> > > index 4e73a531b377..2f20a853d946 100644
> > > --- a/drivers/bluetooth/Kconfig
> > > +++ b/drivers/bluetooth/Kconfig
> > > @@ -41,6 +41,13 @@ config BT_HCIBTUSB_AUTOSUSPEND
> > >           This can be overridden by passing btusb.enable_autosuspend=[y|n]
> > >           on the kernel commandline.
> > >
> > > +config BT_HCIBTUSB_INTERVAL
> > > +       bool "Enable notification of USB polling interval"
> > > +       depends on BT_HCIBTUSB
> > > +       help
> > > +         Say Y here to enable notification of USB polling interval for
> > > +         Bluetooth USB devices by default.
> > > +
> > >  config BT_HCIBTUSB_BCM
> > >         bool "Broadcom protocol support"
> > >         depends on BT_HCIBTUSB
> > > diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
> > > index b14102fba601..38cb5448fc69 100644
> > > --- a/drivers/bluetooth/btusb.c
> > > +++ b/drivers/bluetooth/btusb.c
> > > @@ -30,7 +30,7 @@
> > >  static bool disable_scofix;
> > >  static bool force_scofix;
> > >  static bool enable_autosuspend = IS_ENABLED(CONFIG_BT_HCIBTUSB_AUTOSUSPEND);
> > > -
> > > +static bool enable_interval = IS_ENABLED(CONFIG_BT_HCIBTUSB_INTERVAL);
> > >  static bool reset = true;
> > >
> > >  static struct usb_driver btusb_driver;
> > > @@ -519,8 +519,12 @@ struct btusb_data {
> > >
> > >         unsigned long flags;
> > >
> > > -       struct work_struct work;
> > > -       struct work_struct waker;
> > > +       struct work_struct  work;
> > > +       struct work_struct  waker;
> > > +       struct delayed_work rx_work;
> > > +
> > > +       struct sk_buff_head acl_q;
> > > +       struct sk_buff_head evt_q;
> > >
> > >         struct usb_anchor deferred;
> > >         struct usb_anchor tx_anchor;
> > > @@ -557,7 +561,7 @@ struct btusb_data {
> > >         int isoc_altsetting;
> > >         int suspend_count;
> > >
> > > -       int (*recv_event)(struct hci_dev *hdev, struct sk_buff *skb);
> > > +       int (*recv_event)(struct btusb_data *data, struct sk_buff *skb);
> > >         int (*recv_bulk)(struct btusb_data *data, void *buffer, int count);
> > >
> > >         int (*setup_on_usb)(struct hci_dev *hdev);
> > > @@ -707,7 +711,7 @@ static int btusb_recv_intr(struct btusb_data *data, void *buffer, int count)
> > >
> > >                 if (!hci_skb_expect(skb)) {
> > >                         /* Complete frame */
> > > -                       data->recv_event(data->hdev, skb);
> > > +                       data->recv_event(data, skb);
> > >                         skb = NULL;
> > >                 }
> > >         }
> > > @@ -718,6 +722,25 @@ static int btusb_recv_intr(struct btusb_data *data, void *buffer, int count)
> > >         return err;
> > >  }
> > >
> > > +static int btusb_rx_queue(struct btusb_data *data, struct sk_buff *skb,
> > > +                         struct sk_buff_head *queue, unsigned int interval)
> > > +{
> > > +       skb_queue_tail(queue, skb);
> > > +
> > > +       schedule_delayed_work(&data->rx_work, interval);
> > > +
> > > +       return 0;
> > > +}
> > > +
> > > +static int btusb_recv_acl(struct btusb_data *data, struct sk_buff *skb)
> > > +{
> > > +       if (!enable_interval)
> > > +               return hci_recv_frame(data->hdev, skb);
> > > +
> > > +       /* TODO: Calculate polling interval based on endpoint bInterval? */
> > > +       return btusb_rx_queue(data, skb, &data->acl_q, msecs_to_jiffies(1));
> > > +}
> > > +
> > >  static int btusb_recv_bulk(struct btusb_data *data, void *buffer, int count)
> > >  {
> > >         struct sk_buff *skb;
> > > @@ -765,7 +788,7 @@ static int btusb_recv_bulk(struct btusb_data *data, void *buffer, int count)
> > >
> > >                 if (!hci_skb_expect(skb)) {
> > >                         /* Complete frame */
> > > -                       hci_recv_frame(data->hdev, skb);
> > > +                       btusb_recv_acl(data, skb);
> > >                         skb = NULL;
> > >                 }
> > >         }
> > > @@ -1383,9 +1406,13 @@ static int btusb_close(struct hci_dev *hdev)
> > >
> > >         BT_DBG("%s", hdev->name);
> > >
> > > +       cancel_delayed_work(&data->rx_work);
> > >         cancel_work_sync(&data->work);
> > >         cancel_work_sync(&data->waker);
> > >
> > > +       skb_queue_purge(&data->acl_q);
> > > +       skb_queue_purge(&data->evt_q);
> > > +
> > >         clear_bit(BTUSB_ISOC_RUNNING, &data->flags);
> > >         clear_bit(BTUSB_BULK_RUNNING, &data->flags);
> > >         clear_bit(BTUSB_INTR_RUNNING, &data->flags);
> > > @@ -1417,6 +1444,11 @@ static int btusb_flush(struct hci_dev *hdev)
> > >
> > >         BT_DBG("%s", hdev->name);
> > >
> > > +       cancel_delayed_work(&data->rx_work);
> > > +
> > > +       skb_queue_purge(&data->acl_q);
> > > +       skb_queue_purge(&data->evt_q);
> > > +
> > >         usb_kill_anchored_urbs(&data->tx_anchor);
> > >         btusb_free_frags(data);
> > >
> > > @@ -1769,6 +1801,25 @@ static void btusb_waker(struct work_struct *work)
> > >         usb_autopm_put_interface(data->intf);
> > >  }
> > >
> > > +static void btusb_rx_dequeue(struct btusb_data *data,
> > > +                            struct sk_buff_head *queue)
> > > +{
> > > +       struct sk_buff *skb;
> > > +
> > > +       while ((skb = skb_dequeue(queue)))
> > > +               hci_recv_frame(data->hdev, skb);
> > > +}
> > > +
> > > +static void btusb_rx_work(struct work_struct *work)
> > > +{
> > > +       struct btusb_data *data = container_of(work, struct btusb_data,
> > > +                                              rx_work.work);
> > > +
> > > +       /* Process HCI event packets so states changes are synchronized first */
> > > +       btusb_rx_dequeue(data, &data->evt_q);
> > > +       btusb_rx_dequeue(data, &data->acl_q);
> > > +}
> > > +
> > >  static int btusb_setup_bcm92035(struct hci_dev *hdev)
> > >  {
> > >         struct sk_buff *skb;
> > > @@ -2304,10 +2355,8 @@ static void btusb_intel_secure_send_result(struct btusb_data *data,
> > >                 wake_up_bit(&data->flags, BTUSB_DOWNLOADING);
> > >  }
> > >
> > > -static int btusb_recv_event_intel(struct hci_dev *hdev, struct sk_buff *skb)
> > > +static int btusb_recv_event_intel(struct btusb_data *data, struct sk_buff *skb)
> > >  {
> > > -       struct btusb_data *data = hci_get_drvdata(hdev);
> > > -
> > >         if (test_bit(BTUSB_BOOTLOADER, &data->flags)) {
> > >                 struct hci_event_hdr *hdr = (void *)skb->data;
> > >
> > > @@ -2336,7 +2385,7 @@ static int btusb_recv_event_intel(struct hci_dev *hdev, struct sk_buff *skb)
> > >                 }
> > >         }
> > >
> > > -       return hci_recv_frame(hdev, skb);
> > > +       return hci_recv_frame(data->hdev, skb);
> > >  }
> > >
> > >  static int btusb_send_frame_intel(struct hci_dev *hdev, struct sk_buff *skb)
> > > @@ -4279,6 +4328,15 @@ static int btusb_shutdown_qca(struct hci_dev *hdev)
> > >         return 0;
> > >  }
> > >
> > > +static int btusb_recv_evt(struct btusb_data *data, struct sk_buff *skb)
> > > +{
> > > +       if (!enable_interval)
> > > +               return hci_recv_frame(data->hdev, skb);
> > > +
> > > +       /* Don't delay event processing */
> > > +       return btusb_rx_queue(data, skb, &data->evt_q, 0);
> > > +}
> > > +
> > >  static int btusb_probe(struct usb_interface *intf,
> > >                        const struct usb_device_id *id)
> > >  {
> > > @@ -4362,6 +4420,11 @@ static int btusb_probe(struct usb_interface *intf,
> > >
> > >         INIT_WORK(&data->work, btusb_work);
> > >         INIT_WORK(&data->waker, btusb_waker);
> > > +       INIT_DELAYED_WORK(&data->rx_work, btusb_rx_work);
> > > +
> > > +       skb_queue_head_init(&data->acl_q);
> > > +       skb_queue_head_init(&data->evt_q);
> > > +
> > >         init_usb_anchor(&data->deferred);
> > >         init_usb_anchor(&data->tx_anchor);
> > >         spin_lock_init(&data->txlock);
> > > @@ -4378,7 +4441,7 @@ static int btusb_probe(struct usb_interface *intf,
> > >                 data->recv_bulk = btusb_recv_bulk_intel;
> > >                 set_bit(BTUSB_BOOTLOADER, &data->flags);
> > >         } else {
> > > -               data->recv_event = hci_recv_frame;
> > > +               data->recv_event = btusb_recv_evt;
> > >                 data->recv_bulk = btusb_recv_bulk;
> > >         }
> > >
> > > @@ -4867,6 +4930,9 @@ MODULE_PARM_DESC(force_scofix, "Force fixup of wrong SCO buffers size");
> > >  module_param(enable_autosuspend, bool, 0644);
> > >  MODULE_PARM_DESC(enable_autosuspend, "Enable USB autosuspend by default");
> > >
> > > +module_param(enable_interval, bool, 0644);
> > > +MODULE_PARM_DESC(enable_interval, "Enable USB polling interval by default");
> > > +
> > >  module_param(reset, bool, 0644);
> > >  MODULE_PARM_DESC(reset, "Send HCI reset command on initialization");
> > >
> > > --
> > > 2.26.2
> >
> > Can you test these with the set of tests you guys have for Chrome OS?
> >
> > --
> > Luiz Augusto von Dentz


-- 
Luiz Augusto von Dentz