From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johan Hovold Subject: Re: [PATCH v1 1/4] Bluetooth: hci_qca: use wait_until_sent() for power pulses Date: Fri, 16 Nov 2018 10:47:24 +0100 Message-ID: <20181116094724.GO19900@localhost> References: <20181106120528.30342-1-bgodavar@codeaurora.org> <20181106120528.30342-2-bgodavar@codeaurora.org> <20181114152722.GA19900@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Balakrishna Godavarthi Cc: Johan Hovold , marcel@holtmann.org, johan.hedberg@gmail.com, mka@chromium.org, linux-kernel@vger.kernel.org, linux-bluetooth@vger.kernel.org, hemantg@codeaurora.org, linux-arm-msm@vger.kernel.org, Johan Hovold List-Id: linux-arm-msm@vger.kernel.org On Thu, Nov 15, 2018 at 08:04:29PM +0530, Balakrishna Godavarthi wrote: > Hi Johan, > > On 2018-11-14 20:57, Johan Hovold wrote: > > 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 > >> --- > >> 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); > > > > Don't you want a non-zero timeout here? Otherwise you might as well > > call serdev_device_write() directly. > > [Bala]: we need an in definite timeout for these commands. will use > HCI_UART_TX_WAKEUP. > > > Also have you made sure that serdev_device_write_wakeup() is called in > > the drivers write-wakeup callback as serdev_device_write() requires? > > > > See this series in case what you really wanted was to wait indefinitely > > (you can use MAX_SCHEDULE_TIMEOUT): > > > > https://lkml.kernel.org/r/<20181114150904.19653-1-johan@kernel.org> > > [Bala]: thanks for pointers. from > https://lore.kernel.org/patchwork/patch/1012358/ > it was clear to me that i need call below functions in order to > wait until full data is sent. > > serdev_device_write_wakeup() > serdev_device_write() > serdev_device_wait_until_sent() > > correct me whether my understanding is correct. No, serdev_device_write_wakeup() needs to be called from the serdev driver's write_wakeup() callback (as defined in struct struct serdev_device_ops). Either use serdev_device_write_wakeup() as the callback, or call it from your driver's custom write_wakeup() callback. Hmm, I see now that the callbacks are set in hci_uart_register_device() to hci_serdev_client_ops, which is shared by all serdev BT drivers. You may be able to just add the call to the callback defined there so that all Bluetooth drivers can use serdev_device_write(). Johan