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 ACEE2C282CD for ; Mon, 28 Jan 2019 13:45:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7AD792087F for ; Mon, 28 Jan 2019 13:45:58 +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="m6xPf4Ep"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="SY2LvpQc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726694AbfA1Npx (ORCPT ); Mon, 28 Jan 2019 08:45:53 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:38104 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726647AbfA1Npx (ORCPT ); Mon, 28 Jan 2019 08:45:53 -0500 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id BBD7360851; Mon, 28 Jan 2019 13:45:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1548683149; bh=NijZksKMHZ/9rah5scXmUB3OrJFZczGzQ6VzUkGep8o=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=m6xPf4EpSsBG9lfUo/rNmpRLrzq7a1i+5xyL10Pkfzvnp4dX0vI2tCMuBVVoWCmgr NDLHlYiltB0nV/vZB5zWDHorZjZPZJDBpZ33jaQah+AE+WP1A4wD45V7P/fjpnrHc9 EOAfZfRpxmGJCeReD5VBP0dIm/b3GqnQYeU0Aw8k= Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id 96F37602F8; Mon, 28 Jan 2019 13:45:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1548683148; bh=NijZksKMHZ/9rah5scXmUB3OrJFZczGzQ6VzUkGep8o=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=SY2LvpQcnWz1AbmI4sSoLc/4vfe8818ZqErzQZO3GzmuJbs3Sg68Ri7TO2u+1bIAZ TRXmtpIE8uJlIaCTGqRa7E+j2yRMPbaLZ29y9/ntjYC2VwUHcGQIdG+R84UQ6pDbrh CD2K+dO3DgZ8HLZ+aVK5E1oFxc2bi+t2SylTP8rA= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Mon, 28 Jan 2019 19:15:48 +0530 From: Balakrishna Godavarthi 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 Subject: Re: [PATCH v9 2/3] Bluetooth: hci_qca: Deassert RTS while baudrate change command In-Reply-To: <20190125001259.GB81583@google.com> References: <20190124120808.8275-1-bgodavar@codeaurora.org> <20190124120808.8275-3-bgodavar@codeaurora.org> <20190125001259.GB81583@google.com> Message-ID: <6b18e30fb1b747d674a75cb265b5821b@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 2019-01-25 05:42, Matthias Kaehlcke wrote: > Hi Balakrishna, > > On Thu, Jan 24, 2019 at 05:38:07PM +0530, Balakrishna Godavarthi wrote: >> This patch will help to stop frame reassembly errors while changing >> the baudrate. This is because host send a change baudrate request >> command to the chip with 115200 bps, Whereas chip will change their >> UART clocks to the enable for new baudrate and sends the response >> for the change request command with newer baudrate, On host side >> we are still operating in 115200 bps which results of reading garbage >> data. Here we are pulling RTS line, so that chip we will wait to send >> data >> to host until host change its baudrate. >> >> Signed-off-by: Balakrishna Godavarthi >> Tested-by: Matthias Kaehlcke >> Reviewed-by: Matthias Kaehlcke >> --- >> Changes in v9: >> * disabled flow control while setting the baudrate of HOST and chip. >> --- >> drivers/bluetooth/hci_qca.c | 24 +++++++++++++----------- >> 1 file changed, 13 insertions(+), 11 deletions(-) >> >> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c >> index c08f4d105e73..6b5bcd44e24c 100644 >> --- a/drivers/bluetooth/hci_qca.c >> +++ b/drivers/bluetooth/hci_qca.c >> @@ -964,7 +964,6 @@ static int qca_set_baudrate(struct hci_dev *hdev, >> uint8_t baudrate) >> struct hci_uart *hu = hci_get_drvdata(hdev); >> struct qca_data *qca = hu->priv; >> struct sk_buff *skb; >> - struct qca_serdev *qcadev; >> u8 cmd[] = { 0x01, 0x48, 0xFC, 0x01, 0x00 }; >> >> if (baudrate > QCA_BAUDRATE_3200000) >> @@ -978,13 +977,6 @@ static int qca_set_baudrate(struct hci_dev *hdev, >> uint8_t baudrate) >> return -ENOMEM; >> } >> >> - /* Disabling hardware flow control is mandatory while >> - * sending change baudrate request to wcn3990 SoC. >> - */ >> - qcadev = serdev_device_get_drvdata(hu->serdev); >> - if (qcadev->btsoc_type == QCA_WCN3990) >> - hci_uart_set_flow_control(hu, true); >> - >> /* Assign commands to change baudrate and packet type. */ >> skb_put_data(skb, cmd, sizeof(cmd)); >> hci_skb_pkt_type(skb) = HCI_COMMAND_PKT; >> @@ -1000,9 +992,6 @@ static int qca_set_baudrate(struct hci_dev *hdev, >> uint8_t baudrate) >> schedule_timeout(msecs_to_jiffies(BAUDRATE_SETTLE_TIMEOUT_MS)); >> set_current_state(TASK_RUNNING); >> >> - if (qcadev->btsoc_type == QCA_WCN3990) >> - hci_uart_set_flow_control(hu, false); >> - >> return 0; >> } >> >> @@ -1089,6 +1078,7 @@ static int qca_check_speeds(struct hci_uart *hu) >> static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type >> speed_type) >> { >> unsigned int speed, qca_baudrate; >> + struct qca_serdev *qcadev; >> int ret; >> >> if (speed_type == QCA_INIT_SPEED) { >> @@ -1100,6 +1090,15 @@ static int qca_set_speed(struct hci_uart *hu, >> enum qca_speed_type speed_type) >> if (!speed) >> return 0; >> >> + /* Deassert RTS while changing the baudrate of chip and host. >> + * This will prevent chip from transmitting its response with >> + * the new baudrate while the host port is still operating at >> + * the old speed. >> + */ > > It is not necessarily evident which action deasserts RTS, I suggest to > rephrase it to something like: > > "Disable flow control for wcn3990 to deassert RTS while ... " > [Bala]: will update. >> + qcadev = serdev_device_get_drvdata(hu->serdev); >> + if (qcadev->btsoc_type == QCA_WCN3990) >> + hci_uart_set_flow_control(hu, true); >> + >> qca_baudrate = qca_get_baudrate_value(speed); >> bt_dev_dbg(hu->hdev, "Set UART speed to %d", speed); >> ret = qca_set_baudrate(hu->hdev, qca_baudrate); > > flow control should be re-enabled in the error path. > > Cheers > > Matthias [Bala; will update. -- Regards Balakrishna.