Messages in this thread | | | Date | Thu, 06 Dec 2018 16:10:07 +0530 | From | Balakrishna Godavarthi <> | Subject | Re: [PATCH v3 1/4] Bluetooth: hci_qca: use wait_until_sent() for power pulses |
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Hi Johan,
On 2018-12-05 11:55, Johan Hovold wrote: > On Fri, Nov 30, 2018 at 08:32:44PM +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> >> --- >> v3: >> * no change. >> v2: >> * Updated function qca_send_power_pulse() >> * addressed reviewer comments. > > Please make sure to include reviewers on CC when resending, and as > someone else already mentioned, be a bit more specific about what > changes you actually made in response to the review feedback you > received. >
[Bala]: sure will add and provide more info in version change history.
>> v1: >> * initial patch >> --- >> drivers/bluetooth/hci_qca.c | 37 >> +++++++++++++------------------------ >> 1 file changed, 13 insertions(+), 24 deletions(-) >> >> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c >> index f036c8f98ea3..f5dd323c1967 100644 >> --- a/drivers/bluetooth/hci_qca.c >> +++ b/drivers/bluetooth/hci_qca.c >> @@ -1013,11 +1013,9 @@ 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; >> >> /* These power pulses are single byte command which are sent >> * at required baudrate to wcn3990. On wcn3990, we have an external >> @@ -1029,19 +1027,16 @@ 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 SoC", cmd); >> hci_uart_set_flow_control(hu, true); >> + ret = serdev_device_write(hu->serdev, &cmd, sizeof(cmd), 0); > > You're still using 0 as a timeout here which is broken, as I already > told you. >
[Bala]: got the change now will update to timeout to non zero value.
> From 4.21 this will result in an indefinite timeout, but currently > implies not to wait for a full write buffer to drain at all. > > As I also mentioned, you need to to make sure to call > serdev_device_write_wakeup() in the write_wakup() path if you are going > to use serdev_device_write() at all. >
[Bala]: this where i am confused. calling serdev_device_write is calling an wakeup internally. below is the flow
ttyport_write_buf: * calling serdev_device_write() will call write_buf() in this call we are enabling bit "TTY_DO_WRITE_WAKEUP" and calling write() i.e. uart_write() where we call in start_tx. this will go to the vendor specific write where in isr we call uart_write_wakeup()
https://elixir.bootlin.com/linux/latest/source/drivers/tty/serial/qcom_geni_serial.c#L756
uart_write_wakeup()->ttyport_write_wakeup()->serdev_controller_write_wakeup()->hci_uart_write_wakeup()->hci_uart_tx_wakeup()
the above is flow when serdev_device_write() is called, it is indirectly calling serdev_write_wakeup().
Why actual we need to call an serdev_write_wakeup() is this wakeup related to the UART port or for the BT chip.
> Johan
-- Regards Balakrishna.
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