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Subject: Re: [PATCH v2] Bluetooth: btusb: hci_event: handle msbc audio over
 USB Endpoints
From:   Marcel Holtmann <marcel@holtmann.org>
In-Reply-To: <EFE6F46E14A5F445949D76A8CAC2240058458279@PGSMSX105.gar.corp.intel.com>
Date:   Mon, 14 Oct 2019 15:09:39 +0200
Cc:     "linux-bluetooth@vger.kernel.org" <linux-bluetooth@vger.kernel.org>,
        "Tumkur Narayan, Chethan" <chethan.tumkur.narayan@intel.com>,
        "Narasimman, Sathish" <sathish.narasimman@intel.com>,
        "Hegde, Raghuram" <raghuram.hegde@intel.com>,
        Hsin-Yu Chao <hychao@chromium.org>
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Message-Id: <D64FCFA0-BEB8-4AB6-90DD-6F6F613A3373@holtmann.org>
References: <1569557518-16750-1-git-send-email-amit.k.bag@intel.com>
 <EFE6F46E14A5F445949D76A8CAC2240058458279@PGSMSX105.gar.corp.intel.com>
To:     "Bag, Amit K" <amit.k.bag@intel.com>
Sender: linux-bluetooth-owner@vger.kernel.org
Precedence: bulk

Hi Amit,

>> For msbc encoded audio stream over usb transport, btusb driver to be set to alternate settings 6 as per BT core spec 5.0. This done from  hci_sync_conn_complete_evt.  The type of air mode is known during this event.  For this reason the btusb is to be notifed about the TRANSPARENT air mode and the ALT setting 6 is selected.
>> 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
>> 
>> (am from https://www.spinics.net/lists/linux-bluetooth/msg76982.html)
>> 
>> Signed-off-by: Chethan T N <chethan.tumkur.narayan@intel.com>
>> Signed-off-by: Sathish Narasimman <sathish.narasimman@intel.com>
>> Signed-off-by: Raghuram Hegde <raghuram.hegde@intel.com>
>> Signed-off-by: Hsin-Yu Chao <hychao@chromium.org>
>> Signed-off-by: Amit K Bag <amit.k.bag@intel.com>
>> 
>> Signed-off-by: Amit K Bag <amit.k.bag@intel.com>
>> ---
>> drivers/bluetooth/btusb.c   | 138 +++++++++++++++++++++++++++++---------------
>> include/net/bluetooth/hci.h |   1 +
>> net/bluetooth/hci_event.c   |   5 ++
>> 3 files changed, 99 insertions(+), 45 deletions(-)
>> 
>> diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c index a9c35ebb30f8..f52acced68f8 100644
>> --- a/drivers/bluetooth/btusb.c
>> +++ b/drivers/bluetooth/btusb.c
>> @@ -57,6 +57,9 @@ static struct usb_driver btusb_driver;
>> #define BTUSB_IFNUM_2		0x80000
>> #define BTUSB_CW6622		0x100000
>> #define BTUSB_MEDIATEK		0x200000
>> +#define BTUSB_ALT6_FLOW_CNTRL	6
>> +
>> +static int set_hci_packet_interval_flow = BTUSB_ALT6_FLOW_CNTRL;
>> 
>> static const struct usb_device_id btusb_table[] = {
>> 	/* Generic Bluetooth USB device */
>> @@ -974,6 +977,38 @@ static void btusb_isoc_complete(struct urb *urb)
>> 	}
>> }
>> 
>> +static inline void __fill_isoc_descriptor_msbc(struct urb *urb, int len,
>> +					       int mtu)
>> +{
>> +	int i, offset = 0;
>> +
>> +	/* 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 (set_hci_packet_interval_flow == 6)
>> +		set_hci_packet_interval_flow = 7;
>> +	else if (set_hci_packet_interval_flow == 7)
>> +		set_hci_packet_interval_flow = 6;
>> +
>> +	BT_DBG("len %d mtu %d", len, mtu);
>> +
>> +	for (i = 0; i < set_hci_packet_interval_flow; 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;
>> @@ -1376,9 +1411,12 @@ 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));
>> +	else
>> +		__fill_isoc_descriptor(urb, skb->len,
>> 			       le16_to_cpu(data->isoc_tx_ep->wMaxPacketSize));
>> -
>> 	skb->dev = (void *)hdev;
>> 
>> 	return urb;
>> @@ -1466,18 +1504,6 @@ static int btusb_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
>> 	return -EILSEQ;
>> }
>> 
>> -static void btusb_notify(struct hci_dev *hdev, unsigned int evt) -{
>> -	struct btusb_data *data = hci_get_drvdata(hdev);
>> -
>> -	BT_DBG("%s evt %d", hdev->name, evt);
>> -
>> -	if (hci_conn_num(hdev, SCO_LINK) != data->sco_num) {
>> -		data->sco_num = hci_conn_num(hdev, SCO_LINK);
>> -		schedule_work(&data->work);
>> -	}
>> -}
>> -
>> static inline int __set_isoc_interface(struct hci_dev *hdev, int altsetting)  {
>> 	struct btusb_data *data = hci_get_drvdata(hdev); @@ -1521,6 +1547,58 @@ 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 void btusb_notify(struct hci_dev *hdev, unsigned int evt) {
>> +	struct btusb_data *data = hci_get_drvdata(hdev);
>> +
>> +	BT_DBG("%s evt %d", hdev->name, evt);
>> +
>> +	if (hci_conn_num(hdev, SCO_LINK) != data->sco_num) {
>> +		data->sco_num = hci_conn_num(hdev, SCO_LINK);
>> +		schedule_work(&data->work);
>> +	}
>> +
>> +}
>> +
>> static void btusb_work(struct work_struct *work)  {
>> 	struct btusb_data *data = container_of(work, struct btusb_data, work); @@ -1547,37 +1625,7 @@ static void btusb_work(struct work_struct *work)
>> 		} else {
>> 			new_alts = data->sco_num;
>> 		}
>> -
>> -		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);
>> -
>> -			if (__set_isoc_interface(hdev, new_alts) < 0)
>> -				return;
>> -		}
>> -
>> -		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);
>> -		}
>> +		bt_switch_alt_setting(hdev, new_alts);
>> 	} else {
>> 		clear_bit(BTUSB_ISOC_RUNNING, &data->flags);
>> 		usb_kill_anchored_urbs(&data->isoc_anchor);
>> diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h index 5bc1e30dedde..89ac29f1dffa 100644
>> --- a/include/net/bluetooth/hci.h
>> +++ b/include/net/bluetooth/hci.h
>> @@ -52,6 +52,7 @@
>> #define HCI_NOTIFY_CONN_ADD		1
>> #define HCI_NOTIFY_CONN_DEL		2
>> #define HCI_NOTIFY_VOICE_SETTING	3
>> +#define HCI_NOTIFY_AIR_MODE_TRANSP	4
>> 
>> /* HCI bus types */
>> #define HCI_VIRTUAL	0
>> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index c1d3a303d97f..1c268932422c 100644
>> --- a/net/bluetooth/hci_event.c
>> +++ b/net/bluetooth/hci_event.c
>> @@ -4231,6 +4231,11 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev,
>> 		break;
>> 	}
>> 
>> +	if (ev->air_mode == SCO_AIRMODE_TRANSP) {
>> +		if (hdev->notify)
>> +			hdev->notify(hdev, HCI_NOTIFY_AIR_MODE_TRANSP);
>> +	}
>> +
>> 	hci_connect_cfm(conn, ev->status);
>> 	if (ev->status)
>> 		hci_conn_del(conn);
>> 
> 
> Anything pending in this patch to be merged. 

addressing my comments would help.

Regards

Marcel