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References: <20191129121042.3311-1-sathish.narasimman@intel.com> <20191129121042.3311-2-sathish.narasimman@intel.com>
In-Reply-To: <20191129121042.3311-2-sathish.narasimman@intel.com>
From:   Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Date:   Fri, 29 Nov 2019 15:38:12 +0200
Message-ID: <CABBYNZLrDOrvJ03FehWv1FRNaNWL6SEecZkhSu_VrHzbHo5PGg@mail.gmail.com>
Subject: Re: [PATCH v5 2/2] bluetooth:btusb: handle msbc audio over USB Endpoints
To:     Sathish Narsimman <nsathish41@gmail.com>
Cc:     "linux-bluetooth@vger.kernel.org" <linux-bluetooth@vger.kernel.org>,
        Sathish Narasimman <sathish.narasimman@intel.com>,
        Chethan T N <chethan.tumkur.narayan@intel.com>,
        Hsin-Yu Chao <hychao@chromium.org>,
        Amit K Bag <amit.k.bag@intel.com>
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Sender: linux-bluetooth-owner@vger.kernel.org
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Hi Sathish,

On Fri, Nov 29, 2019 at 2:16 PM Sathish Narsimman <nsathish41@gmail.com> wrote:
>
> From: Sathish Narasimman <sathish.narasimman@intel.com>
>
> For msbc encoded audio stream over usb transport, btusb driver
> to be set to alternate settings 6 as per BT core spec 5.0. The
> type of air mode is used to differenting which alt setting to be
> used.
> The changes are made considering some discussion over the similar
> patch submitted earlier from Kuba Pawlak(link below)
> https://www.spinics.net/lists/linux-bluetooth/msg64577.html
>
> Reported-by: kbuild test robot <lkp@intel.com>
> Signed-off-by: Sathish Narasimman <sathish.narasimman@intel.com>
> Signed-off-by: Chethan T N <chethan.tumkur.narayan@intel.com>
> Signed-off-by: Hsin-Yu Chao <hychao@chromium.org>
> Signed-off-by: Amit K Bag <amit.k.bag@intel.com>
> ---
>  drivers/bluetooth/btusb.c | 157 +++++++++++++++++++++++++++++---------
>  1 file changed, 121 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
> index 9b587e662b48..541048d647d4 100644
> --- a/drivers/bluetooth/btusb.c
> +++ b/drivers/bluetooth/btusb.c
> @@ -483,6 +483,8 @@ struct btusb_data {
>         __u8 cmdreq;
>
>         unsigned int sco_num;
> +       unsigned int air_mode;
> +       bool usb_alt6_packet_flow;
>         int isoc_altsetting;
>         int suspend_count;
>
> @@ -974,6 +976,42 @@ static void btusb_isoc_complete(struct urb *urb)
>         }
>  }
>
> +static inline void __fill_isoc_descriptor_msbc(struct urb *urb, int len,
> +                                              int mtu, bool packet_flow)

Well I guess is really a role for alt6 since afaik mSBC can be sent in
other settings as as well, besides we should never assume a specific
codec is in use since the userspace can use anything with transparent.

> +{
> +       int i, offset = 0;
> +       unsigned int interval;
> +
> +       /* For msbc ALT 6 setting the host will send the packet at continuous
> +        * flow. As per core spec 5, vol 4, part B, table 2.1. For ALT setting
> +        * 6 the HCI PACKET INTERVAL should be 7.5ms for every usb packets.
> +        * To maintain the rate we send 63bytes of usb packets alternatively for
> +        * 7ms and 8ms to maintain the rate as 7.5ms.
> +        */
> +       if (packet_flow) {
> +               interval = 7;
> +               packet_flow = false;
> +       } else {
> +               interval = 6;
> +               packet_flow = true;
> +       }
> +
> +       BT_DBG("interval:%d len %d mtu %d", interval, len, mtu);
> +
> +       for (i = 0; i < interval; i++) {
> +               urb->iso_frame_desc[i].offset = offset;
> +               urb->iso_frame_desc[i].length = offset;
> +       }
> +
> +       if (len && i < BTUSB_MAX_ISOC_FRAMES) {
> +               urb->iso_frame_desc[i].offset = offset;
> +               urb->iso_frame_desc[i].length = len;
> +               i++;
> +       }
> +
> +       urb->number_of_packets = i;
> +}
> +
>  static inline void __fill_isoc_descriptor(struct urb *urb, int len, int mtu)
>  {
>         int i, offset = 0;
> @@ -1377,9 +1415,13 @@ static struct urb *alloc_isoc_urb(struct hci_dev *hdev, struct sk_buff *skb)
>
>         urb->transfer_flags  = URB_ISO_ASAP;
>
> -       __fill_isoc_descriptor(urb, skb->len,
> +       if (data->isoc_altsetting == 6)
> +               __fill_isoc_descriptor_msbc(urb, skb->len,
> +                              le16_to_cpu(data->isoc_tx_ep->wMaxPacketSize),
> +                              data->usb_alt6_packet_flow);
> +       else
> +               __fill_isoc_descriptor(urb, skb->len,
>                                le16_to_cpu(data->isoc_tx_ep->wMaxPacketSize));
> -
>         skb->dev = (void *)hdev;
>
>         return urb;
> @@ -1475,6 +1517,7 @@ static void btusb_notify(struct hci_dev *hdev, unsigned int evt)
>
>         if (hci_conn_num(hdev, SCO_LINK) != data->sco_num) {
>                 data->sco_num = hci_conn_num(hdev, SCO_LINK);
> +               data->air_mode = evt;
>                 schedule_work(&data->work);
>         }
>  }
> @@ -1522,11 +1565,70 @@ static inline int __set_isoc_interface(struct hci_dev *hdev, int altsetting)
>         return 0;
>  }
>
> +static int bt_switch_alt_setting(struct hci_dev *hdev, int new_alts)
> +{
> +       struct btusb_data *data = hci_get_drvdata(hdev);
> +       int err;
> +
> +       if (data->isoc_altsetting != new_alts) {
> +               unsigned long flags;
> +
> +               clear_bit(BTUSB_ISOC_RUNNING, &data->flags);
> +               usb_kill_anchored_urbs(&data->isoc_anchor);
> +
> +               /* When isochronous alternate setting needs to be
> +                * changed, because SCO connection has been added
> +                * or removed, a packet fragment may be left in the
> +                * reassembling state. This could lead to wrongly
> +                * assembled fragments.
> +                *
> +                * Clear outstanding fragment when selecting a new
> +                * alternate setting.
> +                */
> +               spin_lock_irqsave(&data->rxlock, flags);
> +               kfree_skb(data->sco_skb);
> +               data->sco_skb = NULL;
> +               spin_unlock_irqrestore(&data->rxlock, flags);
> +
> +               err = __set_isoc_interface(hdev, new_alts);
> +               if (err < 0)
> +                       return err;
> +       }
> +       if (!test_and_set_bit(BTUSB_ISOC_RUNNING, &data->flags)) {
> +               if (btusb_submit_isoc_urb(hdev, GFP_KERNEL) < 0)
> +                       clear_bit(BTUSB_ISOC_RUNNING, &data->flags);
> +               else
> +                       btusb_submit_isoc_urb(hdev, GFP_KERNEL);
> +       }
> +
> +       return 0;
> +}
> +
> +static struct usb_host_interface *btusb_find_altsetting(struct btusb_data *data, int alt)
> +{
> +       struct usb_interface *intf = data->isoc;
> +       int i;
> +
> +       BT_DBG("Looking for Alt no :%d", alt);
> +
> +       if (intf == NULL) {
> +               BT_ERR("INterface NULL");
> +               return NULL;
> +       }
> +
> +       for (i = 0; i < intf->num_altsetting; i++) {
> +               if (intf->altsetting[i].desc.bAlternateSetting == alt)
> +                       return &intf->altsetting[i];
> +       }
> +
> +       return NULL;
> +}
> +
>  static void btusb_work(struct work_struct *work)
>  {
>         struct btusb_data *data = container_of(work, struct btusb_data, work);
>         struct hci_dev *hdev = data->hdev;
> -       int new_alts;
> +       int new_alts = 0;
>         int err;
>
>         if (data->sco_num > 0) {
> @@ -1541,44 +1643,27 @@ static void btusb_work(struct work_struct *work)
>                         set_bit(BTUSB_DID_ISO_RESUME, &data->flags);
>                 }
>
> -               if (hdev->voice_setting & 0x0020) {
> -                       static const int alts[3] = { 2, 4, 5 };
> -
> -                       new_alts = alts[data->sco_num - 1];
> -               } else {
> -                       new_alts = data->sco_num;
> -               }
> -
> -               if (data->isoc_altsetting != new_alts) {
> -                       unsigned long flags;
> +               if (data->air_mode == HCI_NOTIFY_ENABLE_SCO_CVSD) {
> +                       if (hdev->voice_setting & 0x0020) {
> +                               static const int alts[3] = { 2, 4, 5 };
>
> -                       clear_bit(BTUSB_ISOC_RUNNING, &data->flags);
> -                       usb_kill_anchored_urbs(&data->isoc_anchor);
> -
> -                       /* When isochronous alternate setting needs to be
> -                        * changed, because SCO connection has been added
> -                        * or removed, a packet fragment may be left in the
> -                        * reassembling state. This could lead to wrongly
> -                        * assembled fragments.
> -                        *
> -                        * Clear outstanding fragment when selecting a new
> -                        * alternate setting.
> -                        */
> -                       spin_lock_irqsave(&data->rxlock, flags);
> -                       kfree_skb(data->sco_skb);
> -                       data->sco_skb = NULL;
> -                       spin_unlock_irqrestore(&data->rxlock, flags);
> +                               new_alts = alts[data->sco_num - 1];
> +                       } else {
> +                               new_alts = data->sco_num;
> +                       }
> +               } else if (data->air_mode == HCI_NOTIFY_ENABLE_SCO_TRANSP) {
>
> -                       if (__set_isoc_interface(hdev, new_alts) < 0)
> -                               return;
> -               }
> +                       data->usb_alt6_packet_flow = true;
>
> -               if (!test_and_set_bit(BTUSB_ISOC_RUNNING, &data->flags)) {
> -                       if (btusb_submit_isoc_urb(hdev, GFP_KERNEL) < 0)
> -                               clear_bit(BTUSB_ISOC_RUNNING, &data->flags);
> +                       /* Check if Alt 6 is supported for Transparent audio*/
> +                       if (btusb_find_altsetting(data, 6))
> +                               new_alts = 6;
>                         else
> -                               btusb_submit_isoc_urb(hdev, GFP_KERNEL);
> +                               BT_ERR("%s Device does not support ALT setting 6", hdev->name);
>                 }
> +
> +               if (bt_switch_alt_setting(hdev, new_alts) < 0)
> +                       BT_ERR("%s Set USB Alt: %d failed!", hdev->name, new_alts);
>         } else {
>                 clear_bit(BTUSB_ISOC_RUNNING, &data->flags);
>                 usb_kill_anchored_urbs(&data->isoc_anchor);
> --
> 2.17.1
>


-- 
Luiz Augusto von Dentz