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=-9.7 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 15574C282C3 for ; Fri, 25 Jan 2019 00:13:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CD7B1217D7 for ; Fri, 25 Jan 2019 00:13:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="nX48F4Nk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728451AbfAYANC (ORCPT ); Thu, 24 Jan 2019 19:13:02 -0500 Received: from mail-pl1-f196.google.com ([209.85.214.196]:32815 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727743AbfAYANB (ORCPT ); Thu, 24 Jan 2019 19:13:01 -0500 Received: by mail-pl1-f196.google.com with SMTP id z23so3675622plo.0 for ; Thu, 24 Jan 2019 16:13:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=B2qbOwfaABSqBpeERv2H4hCD0lY4pVpTYgc+0fjiL7s=; b=nX48F4NkkfAdPI+Jh1GDRQ/ZLXRwonHLYlRA6rT+ZqK50TIcoKhNL1d84LG5smC4Au 2WRLewodvMWdCw6U9fuO+EHtXB9brR6+dYfvrc7lSTI2qVd/JMaRXfHYBFIXPyV1nFtU m5xP/C0K7vT4qoQEJG4/KwAnPzt+ycQscRevQ= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=B2qbOwfaABSqBpeERv2H4hCD0lY4pVpTYgc+0fjiL7s=; b=Vs8cwrrPB5VvaqP2npJFiSz/7gKL+gMJ3Va6BqpXIpYXEwBM7PuFcC6AzLqhJBMZtn CN0kURYkq82egdpILT+/hjRY1H7CcN5+osz0zJBrLnd06iXoM8moCua2PTkkOBxBtDVP 2mRGm7T+kLbeaflsL1lgnUopMHXR4X/Z7s829zZ+aixUbiT7t1ufAeSup3Xp7cU2GHrn InAv0bxsAUov7SgbpqmMAK1xwNrNBeMi84yk8SBRfna7FqD/12sFkovwvcHvDXEBoJMi cge9FLow1Fsl723uwrwIDCxO8qp4rS7zoKRs+OW4FfMHl4VImpVyUs0Uc9l+JXZyROoB 3k9g== X-Gm-Message-State: AJcUukex1bwWFbrH4/9nrHyrMYa+nMrp4++Gr/ur+jn8sAGHAaybNwGi ECACv0744k2KPLflSRkeYDusrQ== X-Google-Smtp-Source: ALg8bN7d3d+1eD3qzuGZ+x5YCQncngun3uHDkFjWHaIRMdyKU/t8VsGIXFsRqI97RnxvBd7V5GklbA== X-Received: by 2002:a17:902:780c:: with SMTP id p12mr8452972pll.197.1548375181020; Thu, 24 Jan 2019 16:13:01 -0800 (PST) Received: from localhost ([2620:15c:202:1:75a:3f6e:21d:9374]) by smtp.gmail.com with ESMTPSA id a4sm24702452pgv.70.2019.01.24.16.13.00 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 24 Jan 2019 16:13:00 -0800 (PST) Date: Thu, 24 Jan 2019 16:12:59 -0800 From: Matthias Kaehlcke To: Balakrishna Godavarthi 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 Message-ID: <20190125001259.GB81583@google.com> References: <20190124120808.8275-1-bgodavar@codeaurora.org> <20190124120808.8275-3-bgodavar@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190124120808.8275-3-bgodavar@codeaurora.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 ... " > + 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