linux-kernel - Re: [PATCH v11 3/3] Bluetooth: hci_qca: Disable IBS state machine and flush Tx buffer

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Date:   Mon, 4 Feb 2019 09:31:28 -0800
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Balakrishna Godavarthi <bgodavar@...eaurora.org>
Cc:     marcel@...tmann.org, johan.hedberg@...il.com,
        linux-kernel@...r.kernel.org, linux-bluetooth@...r.kernel.org,
        hemantg@...eaurora.org, linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v11 3/3] Bluetooth: hci_qca: Disable IBS state machine
 and flush Tx buffer

On Mon, Feb 04, 2019 at 08:36:43PM +0530, Balakrishna Godavarthi wrote:
> During hci down we observed IBS sleep commands are queued in the Tx
> buffer and hci_uart_write_work is sending data to the chip which is
> not required as the chip is powered off. This patch will disable IBS
> and flush the Tx buffer before we turn off the chip.
> 
> Signed-off-by: Balakrishna Godavarthi <bgodavar@...eaurora.org>
> ---
>  drivers/bluetooth/hci_qca.c | 17 +++++++++++++++--
>  1 file changed, 15 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index e3cf0dbfc89d..5e03504c4e0c 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -771,16 +771,17 @@ static int qca_enqueue(struct hci_uart *hu, struct sk_buff *skb)
>  	/* Prepend skb with frame type */
>  	memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);
>  
> +	spin_lock_irqsave(&qca->hci_ibs_lock, flags);
> +
>  	/* Don't go to sleep in middle of patch download or
>  	 * Out-Of-Band(GPIOs control) sleep is selected.
>  	 */
>  	if (!test_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags)) {
>  		skb_queue_tail(&qca->txq, skb);
> +		spin_unlock_irqrestore(&qca->hci_ibs_lock, flags);
>  		return 0;
>  	}
>  
> -	spin_lock_irqsave(&qca->hci_ibs_lock, flags);
> -
>  	/* Act according to current state */
>  	switch (qca->tx_ibs_state) {
>  	case HCI_IBS_TX_AWAKE:
> @@ -1275,6 +1276,18 @@ static const struct qca_vreg_data qca_soc_data = {
>  
>  static void qca_power_shutdown(struct hci_uart *hu)
>  {
> +	struct qca_data *qca = hu->priv;
> +	unsigned long flags;
> +
> +	/* From this point we go into power off state. But serial port is
> +	 * still open, stop queueing the IBS data and flush all the buffered
> +	 * data in skb's.
> +	 */
> +	spin_lock_irqsave(&qca->hci_ibs_lock, flags);
> +	clear_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags);
> +	qca_flush(hu);
> +	spin_unlock_irqrestore(&qca->hci_ibs_lock, flags);
> +
>  	host_set_baudrate(hu, 2400);
>  	qca_send_power_pulse(hu, QCA_WCN3990_POWEROFF_PULSE);
>  	qca_power_setup(hu, false);

Reviewed-by: Matthias Kaehlcke <mka@...omium.org>