From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10526C43387 for ; Fri, 28 Dec 2018 07:11:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CA77B2087F for ; Fri, 28 Dec 2018 07:11:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="G9awb8kk"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="ArBWALbe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728800AbeL1HL1 (ORCPT ); Fri, 28 Dec 2018 02:11:27 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:38816 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727999AbeL1HL1 (ORCPT ); Fri, 28 Dec 2018 02:11:27 -0500 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id A05DA606AC; Fri, 28 Dec 2018 07:11:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1545981085; bh=zvC21DsYjP6O8rYsMcFgO5dBO9t4iGnpB+DAZelr1/s=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=G9awb8kkDKJG81ib3huwfD8XEPQXbaFAVrrJLLHzzrNz+cIvYFHFhZhhLSV7+6EV+ b5OexoAfr1UTMkfE19Rq10sKepv9QI7ZOM+z/+VEPL2j35NiLMAX3SVtYnAtfzvn1J XtPKDpTAbTQOebyCGQkeFTaMG27GvJDKZCiQ0lSY= Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id A9B6D606AC; Fri, 28 Dec 2018 07:11:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1545981084; bh=zvC21DsYjP6O8rYsMcFgO5dBO9t4iGnpB+DAZelr1/s=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=ArBWALbeenRvrkivh+wwW/fBMgN5z3LkOjbNPctuvraGdPyIsjaSfKAu/AQUlPe3m cCjhWxSi1/gllqFNdekjCJksZomR+0vwdquogAQrKj2oJ2kMRvRMvBZd6o+CyJ0dwI mqwnL89//LgxqxeOQwyYpSj01UY9BAbaHc+/kXiw= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Fri, 28 Dec 2018 12:41:24 +0530 From: Balakrishna Godavarthi To: Matthias Kaehlcke 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 v6 1/6] Bluetooth: hci_qca: use wait_until_sent() for power pulses In-Reply-To: <20181227201856.GJ261387@google.com> References: <20181227073136.8431-1-bgodavar@codeaurora.org> <20181227073136.8431-2-bgodavar@codeaurora.org> <20181227201856.GJ261387@google.com> Message-ID: <952efcf13141c6f92d66ddbe396d4983@codeaurora.org> X-Sender: bgodavar@codeaurora.org User-Agent: Roundcube Webmail/1.2.5 Sender: linux-bluetooth-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org HI Matthias, On 2018-12-28 01:48, Matthias Kaehlcke wrote: > On Thu, Dec 27, 2018 at 01:01:31PM +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 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 | 38 >> ++++++++++++++----------------------- >> 1 file changed, 14 insertions(+), 24 deletions(-) >> >> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c >> index f036c8f98ea3..507a2355c758 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 +1027,17 @@ 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; >> - >> + serdev_device_write_flush(hu->serdev); >> + bt_dev_dbg(hu->hdev, "sending power pulse %02x to SoC", cmd); > > nit: why clutter the code flow by putting the log statement in the > middle of code that is actually doing something with the serial > interface? > > In case you respin anyway I suggest to structure it like this: > > bt_dev_dbg(hu->hdev, "sending power pulse %02x to SoC", cmd); > > hci_uart_set_flow_control(hu, true); > serdev_device_write_flush(hu->serdev); > ret = serdev_device_write_buf(hu->serdev, &cmd, sizeof(cmd)); > > >> 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 to SoC", > > nit: especially on 'embedded' devices 'SoC' is typically associated > with the CPU running Linux, you might want to change it to > 'controller'. > [Bala]: will update. >> + 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); > > I said earlier the delay here should be enough to ensure that the byte > gets transferred from a hardware buffer/FIFO to the controller, > however that didn't take into account that the power pulses are sent > with a baudrate of 2400. That translates to ~240 bytes/s, hence a > delay of 5 ms is needed to be on the safe side. > [Bala]: sure will update the delay of 5 ms. > In case you change the delay please also update the comment to make > clear this is not only time for the BT controller to settle, but also > to guarantee that the command was actually sent to the controller. > [Bala]: will update the comment. > So far it seems no problems have been observed, though this could be > thanks to the 100 ms delay in qca_wcn3990_init(). > > Cheers > > Matthias -- Regards Balakrishna.