From mboxrd@z Thu Jan 1 00:00:00 1970 From: Balakrishna Godavarthi Subject: Re: [PATCH v9 1/3] Bluetooth: hci_qca: use wait_until_sent() for power pulses Date: Tue, 29 Jan 2019 18:38:12 +0530 Message-ID: <911775a5d93dc066ab4b96f56b74e341@codeaurora.org> References: <20190124120808.8275-1-bgodavar@codeaurora.org> <20190124120808.8275-2-bgodavar@codeaurora.org> <20190125011412.GE81583@google.com> <0fac93a13ee445569659075cf467ad4d@codeaurora.org> <20190128174750.GG81583@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190128174750.GG81583@google.com> Sender: linux-kernel-owner@vger.kernel.org To: Matthias Kaehlcke Cc: marcel@holtmann.org, johan.hedberg@gmail.com, johan@kernel.org, linux-kernel@vger.kernel.org, linux-bluetooth@vger.kernel.org, hemantg@codeaurora.org, linux-arm-msm@vger.kernel.org List-Id: linux-arm-msm@vger.kernel.org Hi Matthias, On 2019-01-28 23:17, Matthias Kaehlcke wrote: > On Mon, Jan 28, 2019 at 07:19:56PM +0530, Balakrishna Godavarthi wrote: >> 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 >> > > --- >> > > 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. > > Fine. > > With the UART buffer flushed and flow control disabled I wonder though > what makes you think that it could take longer than a few milliseconds > for the byte being put on the wire, short of a bug in the UART driver > or hardware, which (if it existed) shouldn't be worked around here. > [Bala]: i don't see any issue decreasing to milliseconds. will update it to 100ms. >> > > /* 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 >> -- Regards Balakrishna.