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=-9.2 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=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 445DAC43441 for ; Wed, 14 Nov 2018 01:55:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F24CB214F1 for ; Wed, 14 Nov 2018 01:55:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="GwYppH7D" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F24CB214F1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732013AbeKNL4H (ORCPT ); Wed, 14 Nov 2018 06:56:07 -0500 Received: from mail-pl1-f195.google.com ([209.85.214.195]:42723 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731898AbeKNL4H (ORCPT ); Wed, 14 Nov 2018 06:56:07 -0500 Received: by mail-pl1-f195.google.com with SMTP id x21-v6so4231386pln.9 for ; Tue, 13 Nov 2018 17:55:06 -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=mkDhlP+vnX9nlcZ05WMCnjnXQtdM1dvqSuPMuNK8H8g=; b=GwYppH7DxBaANVuE/9CpvdsInLaNmJUFdk5cDHduveMa85uwtv1/SLEZTs4gphalpA tqHrJqGwpX72t+N8TTArvjyv9svJ3t9cEu0qGfofuqoN4cMmXoj7bJbG6/xAlSnG7ew6 9LzPQL2OTcnNkGPVI4bZQJ43sc9bUBFaZx/J0= 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=mkDhlP+vnX9nlcZ05WMCnjnXQtdM1dvqSuPMuNK8H8g=; b=OQO0UaLGjIP/8o0hDycR9sUVyG5HBgeuf41DkV5RsswnFVdgFTthO9W7z+b9QAZVvN XRyG7D3u1JDDekC5rTnC6e1t4SL6QCVrMdeueZM6FiFh5+1+2m8KSKUEtZbv+lKY6JuF Jsg4A/Zc5ZWmXTOpQ0lcWlSDvuVX1luGWfq/3R/8+s0x/o5YBgQDJxYTyOBI15Zh9jk2 GjZIdTHcr3LSMf/VUKB3Ro0zGsyrujlYWHhM+0cLVzCvwuOgsPecht6DA0t11+CpLqVG zAcpbuHF6Xm2pyNCATdN93Mi5HefJVMsVUrrMl5DmYymDOs5ASAJYaAs9fw00HeI1Ogt 84yQ== X-Gm-Message-State: AGRZ1gKqIKXI7cYB2LAWC5pXTJTWeD6Ez2eI/34X+D5OJzgrhyhwTKKz GuIWSH2DGTwenGHloHfc7Z7k+g== X-Google-Smtp-Source: AJdET5ehskN547xGoFPBB3qc2LzXzISQGt6bpnAqoIuRkU7XV/ZO0XPlWjp9WjYMVpZCTd5gZetDCA== X-Received: by 2002:a17:902:bd8e:: with SMTP id q14mr3195633pls.146.1542160506513; Tue, 13 Nov 2018 17:55:06 -0800 (PST) Received: from localhost ([2620:15c:202:1:b6af:f85:ed6c:ac6a]) by smtp.gmail.com with ESMTPSA id q195sm21810305pgq.7.2018.11.13.17.55.05 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 13 Nov 2018 17:55:05 -0800 (PST) Date: Tue, 13 Nov 2018 17:55:04 -0800 From: Matthias Kaehlcke To: Balakrishna Godavarthi 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 v1 2/4] Bluetooth: hci_qca: Pull RTS line high for baudrate change command Message-ID: <20181114015504.GH22824@google.com> References: <20181106120528.30342-1-bgodavar@codeaurora.org> <20181106120528.30342-3-bgodavar@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20181106120528.30342-3-bgodavar@codeaurora.org> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 06, 2018 at 05:35:26PM +0530, Balakrishna Godavarthi wrote: > This patch will pull the RTS line high instead of turning off the > flow control, while changing baudrate of host and chip. Please don't only describe what is changed, but also why this change is necessary. IIUC the BT chip honors flow control during baudrate changes, however it sometimes sends 'garbage' which results in "Bluetooth: hci0: Frame reassembly failed (-84)" messages. > Signed-off-by: Balakrishna Godavarthi > --- > drivers/bluetooth/hci_qca.c | 23 ++++++++++++----------- > 1 file changed, 12 insertions(+), 11 deletions(-) > > diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c > index 051f081d1835..8301663f0004 100644 > --- a/drivers/bluetooth/hci_qca.c > +++ b/drivers/bluetooth/hci_qca.c > @@ -963,7 +963,6 @@ 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) > @@ -977,13 +976,6 @@ 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; > @@ -999,9 +991,6 @@ 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; > } > > @@ -1086,6 +1075,7 @@ 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) { > @@ -1097,6 +1087,14 @@ static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type speed_type) > if (!speed) > return 0; > > + /* Pulling RTS line to high is mandatory while sending change > + * baudrate request to SoC and also while setting the host > + * baudrate. > + */ Instead of just stating that this is 'mandatory' explain why it is needed. Also better say 'Deassert RTS' instead of the more lower level 'Pulling RTS line to high'. It could be something like 'Deassert RTS to prevent the BT controller from sending garbage during the baudrate change.' > + qcadev = serdev_device_get_drvdata(hu->serdev); > + if (qcadev->btsoc_type == QCA_WCN3990) > + serdev_device_set_rts(hu->serdev, false); > + > 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); > @@ -1104,6 +1102,9 @@ static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type speed_type) > return ret; > > host_set_baudrate(hu, speed); > + > + if (qcadev->btsoc_type == QCA_WCN3990) > + serdev_device_set_rts(hu->serdev, true); > } > > return 0; Tested-by: Matthias Kaehlcke