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=-6.7 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS 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 C4745C5CFFE for ; Tue, 11 Dec 2018 16:24:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7EE3820870 for ; Tue, 11 Dec 2018 16:24:43 +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="cFQUEbuV"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="apM5iSjq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7EE3820870 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-bluetooth-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727703AbeLKQYk (ORCPT ); Tue, 11 Dec 2018 11:24:40 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:44406 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727273AbeLKPmh (ORCPT ); Tue, 11 Dec 2018 10:42:37 -0500 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id F226660913; Tue, 11 Dec 2018 15:42:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1544542957; bh=6ggL3c3Hm2Qsp/HijtdSknvW4aClXsInkiPhUrDPlB8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=cFQUEbuVRHeEnnXhh5H7rPcAJIzxwLJ7vCuZ5lY++q0y1z5HbwaEcY9VYThaMGjfD UDHgQxqYwdBUjFhLmmjGw5SW26iO80Y6I7z5FVRMXQzKZaTFh+8RSinH8rA1vb7QJd PlPLBAn9RH2kxW4fcS3TJg8ICMt28dAT9LPnBkB8= Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id A423A6029D; Tue, 11 Dec 2018 15:42:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1544542954; bh=6ggL3c3Hm2Qsp/HijtdSknvW4aClXsInkiPhUrDPlB8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=apM5iSjqEF/jsht4JPWKj87KMONWckUjtWKwwS0NIoolnf+UwtiYouZ3WHc/ZMHnV QVdhdBvwE7MkrXWKmhgKLeEqinUrefPfAoqG6SRnC9yj4PryfgkOn2g5WcY9xxZe23 tlMWMZDSI/Q4OFSia8Q+csujUjFnmK6FVMHjsNFY= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Tue, 11 Dec 2018 21:12:34 +0530 From: Balakrishna Godavarthi To: Johan Hovold Cc: marcel@holtmann.org, johan.hedberg@gmail.com, mka@chromium.org, linux-kernel@vger.kernel.org, linux-bluetooth@vger.kernel.org, hemantg@codeaurora.org, linux-arm-msm@vger.kernel.org, Johan Hovold Subject: Re: [PATCH v3 1/4] Bluetooth: hci_qca: use wait_until_sent() for power pulses In-Reply-To: References: <20181130150247.26294-1-bgodavar@codeaurora.org> <20181130150247.26294-2-bgodavar@codeaurora.org> <20181205062503.GG18087@localhost> Message-ID: <0a8cc07b08ee10812a99b46c78e616ce@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 Johan, On 2018-12-06 16:10, Balakrishna Godavarthi wrote: > Hi Johan, > > On 2018-12-05 11:55, Johan Hovold wrote: >> On Fri, Nov 30, 2018 at 08:32:44PM +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 >>> --- >>> v3: >>> * no change. >>> v2: >>> * Updated function qca_send_power_pulse() >>> * addressed reviewer comments. >> >> Please make sure to include reviewers on CC when resending, and as >> someone else already mentioned, be a bit more specific about what >> changes you actually made in response to the review feedback you >> received. >> > > [Bala]: sure will add and provide more info in version change history. > >>> v1: >>> * initial patch >>> --- >>> drivers/bluetooth/hci_qca.c | 37 >>> +++++++++++++------------------------ >>> 1 file changed, 13 insertions(+), 24 deletions(-) >>> >>> diff --git a/drivers/bluetooth/hci_qca.c >>> b/drivers/bluetooth/hci_qca.c >>> index f036c8f98ea3..f5dd323c1967 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 +1027,16 @@ 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 SoC", cmd); >>> hci_uart_set_flow_control(hu, true); >>> + ret = serdev_device_write(hu->serdev, &cmd, sizeof(cmd), 0); >> >> You're still using 0 as a timeout here which is broken, as I already >> told you. >> > > [Bala]: got the change now will update to timeout to non zero value. > >> From 4.21 this will result in an indefinite timeout, but currently >> implies not to wait for a full write buffer to drain at all. >> >> As I also mentioned, you need to to make sure to call >> serdev_device_write_wakeup() in the write_wakup() path if you are >> going >> to use serdev_device_write() at all. >> > > [Bala]: this where i am confused. > calling serdev_device_write is calling an wakeup internally. > below is the flow > > ttyport_write_buf: > * calling serdev_device_write() will call write_buf() in > this call we are enabling bit "TTY_DO_WRITE_WAKEUP" and calling > write() > i.e. uart_write() where we call in start_tx. this will > go to the vendor specific write where in isr we call > uart_write_wakeup() > > https://elixir.bootlin.com/linux/latest/source/drivers/tty/serial/qcom_geni_serial.c#L756 > > > uart_write_wakeup()->ttyport_write_wakeup()->serdev_controller_write_wakeup()->hci_uart_write_wakeup()->hci_uart_tx_wakeup() > > the above is flow when serdev_device_write() is called, it is > indirectly calling serdev_write_wakeup(). > > Why actual we need to call an serdev_write_wakeup() is this > wakeup related to the UART port or for the BT chip. > >> Johan Can you help me to understand, whether my understating is correct wrt serdev_wakeup(). -- Regards Balakrishna.