From: Matthias Kaehlcke <mka@chromium.org>
To: Balakrishna Godavarthi <bgodavar@codeaurora.org>
Cc: marcel@holtmann.org, johan.hedberg@gmail.com,
linux-kernel@vger.kernel.org, linux-bluetooth@vger.kernel.org,
hemantg@codeaurora.org, linux-arm-msm@vger.kernel.org
Subject: Re: [PATCH v1 1/4] Bluetooth: hci_qca: use wait_until_sent() for power pulses
Date: Tue, 13 Nov 2018 16:17:17 -0800 [thread overview]
Message-ID: <20181114001717.GG22824@google.com> (raw)
In-Reply-To: <20181106120528.30342-2-bgodavar@codeaurora.org>
On Tue, Nov 06, 2018 at 05:35:25PM +0530, Balakrishna Godavarthi wrote:
> wcn3990 requires a power pulse to turn ON/OFF along with
> regulators. Sometimes we are observing the power pulses are sent
> out with some time delay, due to queuing these commands. This is
> causing synchronization issues with chip, which intern delay the
> chip setup or may end up with communication issues.
>
> Signed-off-by: Balakrishna Godavarthi <bgodavar@codeaurora.org>
> ---
> drivers/bluetooth/hci_qca.c | 22 +++++++++-------------
> 1 file changed, 9 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index f72ded4ec9ae..051f081d1835 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -1016,8 +1016,7 @@ static inline void host_set_baudrate(struct hci_uart *hu, unsigned int speed)
> static int qca_send_power_pulse(struct hci_dev *hdev, u8 cmd)
> {
> struct hci_uart *hu = hci_get_drvdata(hdev);
> - struct qca_data *qca = hu->priv;
> - struct sk_buff *skb;
> + int ret;
>
> /* These power pulses are single byte command which are sent
> * at required baudrate to wcn3990. On wcn3990, we have an external
> @@ -1030,18 +1029,14 @@ static int qca_send_power_pulse(struct hci_dev *hdev, u8 cmd)
> * sending power pulses to SoC.
> */
> bt_dev_dbg(hdev, "sending power pulse %02x to SoC", cmd);
> -
> - skb = bt_skb_alloc(sizeof(cmd), GFP_KERNEL);
> - if (!skb)
> - return -ENOMEM;
> -
> hci_uart_set_flow_control(hu, true);
> + ret = serdev_device_write(hu->serdev, &cmd, sizeof(cmd), 0);
> + if (ret < 0) {
> + bt_dev_err(hdev, "failed to send power pulse %02x to SoC", cmd);
> + return ret;
> + }
>
> - skb_put_u8(skb, cmd);
> - hci_skb_pkt_type(skb) = HCI_COMMAND_PKT;
> -
> - skb_queue_tail(&qca->txq, skb);
> - hci_uart_tx_wakeup(hu);
> + serdev_device_wait_until_sent(hu->serdev, 0);
>
> /* Wait for 100 uS for SoC to settle down */
> usleep_range(100, 200);
Is the delay still needed now that we wait for the pulse to be sent? I
didn't observe any problems without it in a few dozens of iterations.
> @@ -1283,7 +1278,8 @@ static void qca_power_shutdown(struct hci_uart *hu)
>
> host_set_baudrate(hu, 2400);
> hci_uart_set_flow_control(hu, true);
> - serdev_device_write_buf(serdev, &cmd, sizeof(cmd));
> + serdev_device_write(serdev, &cmd, sizeof(cmd), 0);
> + serdev_device_wait_until_sent(serdev, 0);
> hci_uart_set_flow_control(hu, false);
You could call qca_send_power_pulse(hdev, QCA_WCN3990_POWEROFF_PULSE)
instead, as an earlier patch set did before skbs were used to send the
power pulse.
You can also consider to set the baudrate in qca_send_power_pulse()
depending on the power pulse. On the plus side this would reduce a bit
of clutter in the callers of qca_send_power_pulse(), on the negative
side it would be harder to follow when baudrate changes occur (not
sure this is a problem). Up to you, just an idea.
Thanks
Matthias
next prev parent reply other threads:[~2018-11-14 0:17 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-06 12:05 Bug fixes for Qualcomm BT chip wcn3990 Balakrishna Godavarthi
2018-11-06 12:05 ` [PATCH v1 1/4] Bluetooth: hci_qca: use wait_until_sent() for power pulses Balakrishna Godavarthi
2018-11-14 0:17 ` Matthias Kaehlcke [this message]
2018-11-14 6:29 ` Balakrishna Godavarthi
2018-11-14 15:27 ` Johan Hovold
2018-11-15 14:34 ` Balakrishna Godavarthi
2018-11-16 9:47 ` Johan Hovold
2018-11-06 12:05 ` [PATCH v1 2/4] Bluetooth: hci_qca: Pull RTS line high for baudrate change command Balakrishna Godavarthi
2018-11-14 1:55 ` Matthias Kaehlcke
2018-11-14 6:32 ` Balakrishna Godavarthi
2018-11-06 12:05 ` [PATCH v1 3/4] Bluetooth: hci_qca: clear HCI_QUIRK_RESET_ON_CLOSE flag Balakrishna Godavarthi
2018-11-06 12:33 ` Marcel Holtmann
2018-11-06 12:44 ` Balakrishna Godavarthi
2018-11-06 13:02 ` Marcel Holtmann
2018-11-06 13:14 ` Balakrishna Godavarthi
2018-11-06 13:36 ` Balakrishna Godavarthi
2018-11-14 7:48 ` Marcel Holtmann
2018-11-14 13:37 ` Balakrishna Godavarthi
2018-11-14 2:14 ` Matthias Kaehlcke
2018-11-14 6:50 ` Balakrishna Godavarthi
2018-11-06 12:05 ` [PATCH v1 4/4] Bluetooth: hci_qca: Fix frame reassembly errors for wcn3990 Balakrishna Godavarthi
2018-11-14 19:36 ` Matthias Kaehlcke
2018-11-15 11:40 ` Balakrishna Godavarthi
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