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=-13.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 8232BC433FE for ; Fri, 4 Dec 2020 01:45:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 38B1320575 for ; Fri, 4 Dec 2020 01:45:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726631AbgLDBpS (ORCPT ); Thu, 3 Dec 2020 20:45:18 -0500 Received: from m43-15.mailgun.net ([69.72.43.15]:23761 "EHLO m43-15.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725885AbgLDBpR (ORCPT ); Thu, 3 Dec 2020 20:45:17 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1607046296; h=Message-ID: References: In-Reply-To: Reply-To: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=EDXzLGJb6bJ8qJgZY+dWWcpi504rhSOZhUQPBsX8Hg8=; b=prGizZteiVz2dB/hu0ZoihaZi/l2NPiVY+LtvmrHhsN2bpSVjdKbEDZnq6zp+8UG44BxSpGT 7oHkQEGqAyuj9JrYLVUnfc41TD7QuFfpC6mS49UrF8HC5EtEeYCavABVWTaNVjltZ4Giq01I IE6f5f0GrZIea5f9gu8vt+90F/o= X-Mailgun-Sending-Ip: 69.72.43.15 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n09.prod.us-west-2.postgun.com with SMTP id 5fc9947ded9d5dfa89a6dc56 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Fri, 04 Dec 2020 01:44:29 GMT Sender: bbhatt=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 24F7BC43464; Fri, 4 Dec 2020 01:44:29 +0000 (UTC) Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: bbhatt) by smtp.codeaurora.org (Postfix) with ESMTPSA id 6640EC433CA; Fri, 4 Dec 2020 01:44:28 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Thu, 03 Dec 2020 17:44:28 -0800 From: Bhaumik Bhatt To: Hemant Kumar Cc: manivannan.sadhasivam@linaro.org, linux-arm-msm@vger.kernel.org, loic.poulain@linaro.org, jhugo@codeaurora.org, linux-kernel@vger.kernel.org, hemantk=codeaurora.org@codeaurora.org Subject: Re: [PATCH v3 4/7] bus: mhi: core: Add support to stop or start channel data transfers Organization: Qualcomm Innovation Center, Inc. Reply-To: bbhatt@codeaurora.org Mail-Reply-To: bbhatt@codeaurora.org In-Reply-To: <78cafedf-4d08-e087-a56e-6df88731b2ff@codeaurora.org> References: <1606952438-15321-1-git-send-email-bbhatt@codeaurora.org> <1606952438-15321-5-git-send-email-bbhatt@codeaurora.org> <78cafedf-4d08-e087-a56e-6df88731b2ff@codeaurora.org> Message-ID: <4e03712e353b22eea3096bc67ed03bff@codeaurora.org> X-Sender: bbhatt@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-12-02 04:33 PM, Hemant Kumar wrote: > Hi Bhaumik, > > On 12/2/20 3:40 PM, Bhaumik Bhatt wrote: >> Some MHI client drivers may want to request a pause or halt of >> data transfer activity on their channels. Support for this does >> not exist and must be introduced, wherein the channel context is >> not reset or cleared but only the STOP channel command is issued. >> This would need to be paired with an API that allows resuming the >> data transfer activity on channels by use of the START channel >> command. This API assumes that the context information is already > > is it a better option to make sure channel context is setup as this is > an exported API. Hence check for channel context bail out in case > channel context is not setup with an err msg ? > This is a better method, yes. Addressed in v4. >> setup. Enable this using two new APIs, mhi_start_transfer() and >> mhi_stop_transfer(). >> >> Signed-off-by: Bhaumik Bhatt >> --- >> drivers/bus/mhi/core/main.c | 41 >> +++++++++++++++++++++++++++++++++++++++++ >> include/linux/mhi.h | 19 +++++++++++++++++++ >> 2 files changed, 60 insertions(+) >> >> diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c >> index 4cc5ced..2e4b34a 100644 >> --- a/drivers/bus/mhi/core/main.c >> +++ b/drivers/bus/mhi/core/main.c >> @@ -1552,6 +1552,47 @@ void mhi_unprepare_from_transfer(struct >> mhi_device *mhi_dev) >> } >> EXPORT_SYMBOL_GPL(mhi_unprepare_from_transfer); >> +static int mhi_update_transfer_state(struct mhi_device *mhi_dev, >> + enum mhi_ch_state_type to_state) >> +{ >> + struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl; >> + struct mhi_chan *mhi_chan; >> + int dir, ret; >> + >> + for (dir = 0; dir < 2; dir++) { >> + mhi_chan = dir ? mhi_dev->ul_chan : mhi_dev->dl_chan; >> + >> + if (!mhi_chan) >> + continue; >> + >> + /* >> + * Bail out if one of the channels fail as client will reset >> + * both upon failure >> + */ >> + mutex_lock(&mhi_chan->mutex); >> + ret = mhi_update_channel_state(mhi_cntrl, mhi_chan, to_state); >> + if (ret) { >> + mutex_unlock(&mhi_chan->mutex); >> + return ret; >> + } >> + mutex_unlock(&mhi_chan->mutex); >> + } >> + >> + return 0; >> +} >> + >> +int mhi_stop_transfer(struct mhi_device *mhi_dev) >> +{ >> + return mhi_update_transfer_state(mhi_dev, MHI_CH_STATE_TYPE_STOP); >> +} >> +EXPORT_SYMBOL_GPL(mhi_stop_transfer); >> + >> +int mhi_start_transfer(struct mhi_device *mhi_dev) >> +{ >> + return mhi_update_transfer_state(mhi_dev, MHI_CH_STATE_TYPE_START); >> +} >> +EXPORT_SYMBOL_GPL(mhi_start_transfer); >> + >> int mhi_poll(struct mhi_device *mhi_dev, u32 budget) >> { >> struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl; >> diff --git a/include/linux/mhi.h b/include/linux/mhi.h >> index aa9757e..35779a0 100644 >> --- a/include/linux/mhi.h >> +++ b/include/linux/mhi.h >> @@ -704,6 +704,25 @@ int mhi_prepare_for_transfer(struct mhi_device >> *mhi_dev); >> void mhi_unprepare_from_transfer(struct mhi_device *mhi_dev); >> /** >> + * mhi_stop_transfer - Pauses ongoing channel activity by issuing the >> STOP >> + * channel command to both UL and DL channels. >> This command >> + * does not reset the channel context and the >> client drivers >> + * can issue mhi_start_transfer to resume >> activity. >> + * @mhi_dev: Device associated with the channels >> + */ >> +int mhi_stop_transfer(struct mhi_device *mhi_dev); >> + >> +/** >> + * mhi_start_transfer - Resumes channel activity by issuing the START >> channel >> + * command to both UL and DL channels. This >> command assumes >> + * the channel context is already setup and the >> client >> + * drivers can issue mhi_stop_transfer to pause >> activity if >> + * required. >> + * @mhi_dev: Device associated with the channels >> + */ >> +int mhi_start_transfer(struct mhi_device *mhi_dev); >> + >> +/** >> * mhi_poll - Poll for any available data in DL direction >> * @mhi_dev: Device associated with the channels >> * @budget: # of events to process >> > Overall change looks good. > > Thanks, > Hemant Thanks, Bhaumik --- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project