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Date: Mon, 28 Jan 2019 19:19:56 +0530
From: Balakrishna Godavarthi <bgodavar@...eaurora.org>
To: Matthias Kaehlcke <mka@...omium.org>
Cc: marcel@...tmann.org, johan.hedberg@...il.com, johan@...nel.org,
linux-kernel@...r.kernel.org, linux-bluetooth@...r.kernel.org,
hemantg@...eaurora.org, linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v9 1/3] Bluetooth: hci_qca: use wait_until_sent() for
power pulses
Hi Matthias,
On 2019-01-25 06:44, Matthias Kaehlcke wrote:
> On Thu, Jan 24, 2019 at 05:38:06PM +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@...eaurora.org>
>> ---
>> Changes in v9:
>> * Reverted to 100us sleep.
>> * used inline call msecs_to_jiffies()
>>
>> Changes in v8:
>> * Updated 1 second timeout instead of indefinite wait.
>>
>> Changes in v7:
>> * updated the wait time to 5 ms after sending power pulses.
>>
>> Changes in v6:
>> * added serdev_device_write_flush() in qca_send_power_pulse
>> instead during the power off pulse.
>>
>> Changes in v5:
>> * added serdev_device_write_flush() in qca_power_off().
>> ---
>> drivers/bluetooth/hci_qca.c | 40
>> +++++++++++++++----------------------
>> 1 file changed, 16 insertions(+), 24 deletions(-)
>>
>> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
>> index f036c8f98ea3..c08f4d105e73 100644
>> --- a/drivers/bluetooth/hci_qca.c
>> +++ b/drivers/bluetooth/hci_qca.c
>> @@ -60,6 +60,7 @@
>> #define IBS_WAKE_RETRANS_TIMEOUT_MS 100
>> #define IBS_TX_IDLE_TIMEOUT_MS 2000
>> #define BAUDRATE_SETTLE_TIMEOUT_MS 300
>> +#define POWER_PULSE_TRANS_TIMEOUT_MS 1000
>
> I still doubt that this mega-timeout of 1s is needed, but it shouldn't
> do any harm either, so whatever ...
>
[Bala]: for now let us have it. we can improve it in the improvement
patch
based on the results.
>> /* susclk rate */
>> #define SUSCLK_RATE_32KHZ 32768
>> @@ -1013,11 +1014,10 @@ static inline void host_set_baudrate(struct
>> hci_uart *hu, unsigned int speed)
>> hci_uart_set_baudrate(hu, speed);
>> }
>>
>> -static int qca_send_power_pulse(struct hci_dev *hdev, u8 cmd)
>> +static int qca_send_power_pulse(struct hci_uart *hu, u8 cmd)
>> {
>> - struct hci_uart *hu = hci_get_drvdata(hdev);
>> - struct qca_data *qca = hu->priv;
>> - struct sk_buff *skb;
>> + int ret;
>> + int timeout = msecs_to_jiffies(POWER_PULSE_TRANS_TIMEOUT_MS);
>>
>> /* These power pulses are single byte command which are sent
>> * at required baudrate to wcn3990. On wcn3990, we have an external
>> @@ -1029,21 +1029,19 @@ static int qca_send_power_pulse(struct hci_dev
>> *hdev, u8 cmd)
>> * save power. Disabling hardware flow control is mandatory while
>> * 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;
>> + bt_dev_dbg(hu->hdev, "sending power pulse %02x to controller", cmd);
>>
>> + serdev_device_write_flush(hu->serdev);
>> hci_uart_set_flow_control(hu, true);
>> + ret = serdev_device_write_buf(hu->serdev, &cmd, sizeof(cmd));
>> + if (ret < 0) {
>> + bt_dev_err(hu->hdev, "failed to send power pulse %02x", 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, timeout);
>>
>> - /* Wait for 100 uS for SoC to settle down */
>> + /* Wait for 100 uS for SoC to settle down for the received byte. */
>
> I don't think 'for the received byte' adds much value here. If you
> respin anyway I'd suggest to leave the comment as is.
>
[Bala]: will update.
>> usleep_range(100, 200);
>> hci_uart_set_flow_control(hu, false);
>>
>> @@ -1116,7 +1114,6 @@ static int qca_set_speed(struct hci_uart *hu,
>> enum qca_speed_type speed_type)
>>
>> static int qca_wcn3990_init(struct hci_uart *hu)
>> {
>> - struct hci_dev *hdev = hu->hdev;
>> struct qca_serdev *qcadev;
>> int ret;
>>
>> @@ -1139,12 +1136,12 @@ static int qca_wcn3990_init(struct hci_uart
>> *hu)
>>
>> /* Forcefully enable wcn3990 to enter in to boot mode. */
>> host_set_baudrate(hu, 2400);
>> - ret = qca_send_power_pulse(hdev, QCA_WCN3990_POWEROFF_PULSE);
>> + ret = qca_send_power_pulse(hu, QCA_WCN3990_POWEROFF_PULSE);
>> if (ret)
>> return ret;
>>
>> qca_set_speed(hu, QCA_INIT_SPEED);
>> - ret = qca_send_power_pulse(hdev, QCA_WCN3990_POWERON_PULSE);
>> + ret = qca_send_power_pulse(hu, QCA_WCN3990_POWERON_PULSE);
>> if (ret)
>> return ret;
>>
>> @@ -1274,13 +1271,8 @@ static const struct qca_vreg_data qca_soc_data
>> = {
>>
>> static void qca_power_shutdown(struct hci_uart *hu)
>> {
>> - struct serdev_device *serdev = hu->serdev;
>> - unsigned char cmd = QCA_WCN3990_POWEROFF_PULSE;
>> -
>> host_set_baudrate(hu, 2400);
>> - hci_uart_set_flow_control(hu, true);
>> - serdev_device_write_buf(serdev, &cmd, sizeof(cmd));
>> - hci_uart_set_flow_control(hu, false);
>> + qca_send_power_pulse(hu, QCA_WCN3990_POWEROFF_PULSE);
>> qca_power_setup(hu, false);
>> }
>>
>
> Looks good to me besides possible minor improvements:
>
> Reviewed-by: Matthias Kaehlcke <mka@...omium.org>
--
Regards
Balakrishna.
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