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=-13.7 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,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 F0B6AC433E6 for ; Wed, 23 Dec 2020 03:32:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B7BDF223C8 for ; Wed, 23 Dec 2020 03:32:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728258AbgLWDb5 (ORCPT ); Tue, 22 Dec 2020 22:31:57 -0500 Received: from so254-31.mailgun.net ([198.61.254.31]:47887 "EHLO so254-31.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727973AbgLWDb4 (ORCPT ); Tue, 22 Dec 2020 22:31:56 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1608694292; h=Message-ID: References: In-Reply-To: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=7Rb04fxp2Vgu3LQSPVrNWPRozHdROabaDrF5ER6ENj8=; b=CgtMveOzGDQf2SDuDravYXdyjSizGpnWufcfw8Vcfy1j0nHWGqUg49aGIdyv4EtwwfqW/AzF CB/4BAzFRmIlz71c0uIl27SkpGWKjuV2QdtqL7WwVPGUhBE2Z55xukC30Ye5vsVlYRfqBcGg WVHqdbd77x6dRj/WNpi3M81Wk6Y= X-Mailgun-Sending-Ip: 198.61.254.31 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-n05.prod.us-east-1.postgun.com with SMTP id 5fe2b9f6120d248bb52c6dd4 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Wed, 23 Dec 2020 03:31:02 GMT Sender: cjhuang=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id B1D8CC43463; Wed, 23 Dec 2020 03:31:01 +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: cjhuang) by smtp.codeaurora.org (Postfix) with ESMTPSA id CA5C5C433CA; Wed, 23 Dec 2020 03:31:00 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Date: Wed, 23 Dec 2020 11:31:00 +0800 From: Carl Huang To: Jeffrey Hugo Cc: Hemant Kumar , manivannan.sadhasivam@linaro.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mhi: use irq_flags if client driver configures it In-Reply-To: References: <20201208035500.30581-1-cjhuang@codeaurora.org> Message-ID: X-Sender: cjhuang@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-12-10 03:48, Jeffrey Hugo wrote: > On 12/9/2020 11:34 AM, Hemant Kumar wrote: >> >> >> On 12/7/20 7:55 PM, Carl Huang wrote: >>> If client driver has specified the irq_flags, mhi uses this specified >>> irq_flags. Otherwise, mhi uses default irq_flags. >>> >>> The purpose of this change is to support one MSI vector for QCA6390. >>> MHI will use one same MSI vector too in this scenario. >>> >>> In case of one MSI vector, IRQ_NO_BALANCING is needed when irq >>> handler >>> is requested. The reason is if irq migration happens, the msi_data >>> may >>> change too. However, the msi_data is already programmed to QCA6390 >>> hardware during initialization phase. This msi_data inconsistence >>> will >>> result in crash in kernel. > > I'm confused as to how this happens. > Host needs to program msi_data to QCA6390 hardware components(lots of standard rings), and this msi_data is used to generate MSI interrupt. If kernel has re-assigned msi_data to QCA6390 when irq migration happens, and this re-assigned msi_data is written to QCA6390 PCIe config space only, standard rings still use previous msi_data. >>> >>> Another issue is in case of one MSI vector, IRQF_NO_SUSPEND will >>> trigger >>> WARNINGS because QCA6390 wants to disable the IRQ during the suspend. >>> >>> To avoid above two issues, QCA6390 driver specifies the irq_flags in >>> case >>> of one MSI vector when mhi_register_controller is called. > > Surely this change should be in a series where there is a following > change which updates the QCA6390 driver? > Yes. This patch involves MHI module, so send it separately. There is another patch set for QCA6390 to support one MSI vector. >>> >>> Signed-off-by: Carl Huang >>> --- >>>   drivers/bus/mhi/core/init.c | 9 +++++++-- >>>   include/linux/mhi.h         | 1 + >>>   2 files changed, 8 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/bus/mhi/core/init.c >>> b/drivers/bus/mhi/core/init.c >>> index 0ffdebd..5f74e1e 100644 >>> --- a/drivers/bus/mhi/core/init.c >>> +++ b/drivers/bus/mhi/core/init.c >>> @@ -148,12 +148,17 @@ int mhi_init_irq_setup(struct mhi_controller >>> *mhi_cntrl) >>>   { >>>       struct mhi_event *mhi_event = mhi_cntrl->mhi_event; >>>       struct device *dev = &mhi_cntrl->mhi_dev->dev; >>> +    unsigned long irq_flags = IRQF_SHARED | IRQF_NO_SUSPEND; >>>       int i, ret; >>> +    /* if client driver has set irq_flags, use it */ >>> +    if (mhi_cntrl->irq_flags) >>> +        irq_flags = mhi_cntrl->irq_flags; >> Jeff if i remember correctly your use case also have one dedicated irq >> line for all the MSIs, just want to confirm if you are fine with this >> change ? i was wondering if any input check is required for irq_flags >> passed by controller, or responsibility is on controller for any >> undesired behavior. Like passing IRQF_SHARED and IRQF_ONESHOT when one >> irq line is shared among multiple MSIs. > > This feels a bit weird to me, but I don't think it'll cause a problem. > > If we are allowing the controller to specify flags, should they be in > a per irq manner? > Not sure if per irq manner is needed for others, but ath11k doesn't need per irq manner. >>> + >>>       /* Setup BHI_INTVEC IRQ */ >>>       ret = request_threaded_irq(mhi_cntrl->irq[0], >>> mhi_intvec_handler, >>>                      mhi_intvec_threaded_handler, >>> -                   IRQF_SHARED | IRQF_NO_SUSPEND, >>> +                   irq_flags, >>>                      "bhi", mhi_cntrl); >>>       if (ret) >>>           return ret; >>> @@ -171,7 +176,7 @@ int mhi_init_irq_setup(struct mhi_controller >>> *mhi_cntrl) >>>           ret = request_irq(mhi_cntrl->irq[mhi_event->irq], >>>                     mhi_irq_handler, >>> -                  IRQF_SHARED | IRQF_NO_SUSPEND, >>> +                  irq_flags, >>>                     "mhi", mhi_event); >>>           if (ret) { >>>               dev_err(dev, "Error requesting irq:%d for ev:%d\n", >>> diff --git a/include/linux/mhi.h b/include/linux/mhi.h >>> index d4841e5..f039e58 100644 >>> --- a/include/linux/mhi.h >>> +++ b/include/linux/mhi.h >>> @@ -442,6 +442,7 @@ struct mhi_controller { >>>       bool fbc_download; >>>       bool pre_init; >>>       bool wake_set; >>> +    unsigned long irq_flags; > > You don't document this. That gets a NACK from me. > Yes, will document this field in V2. >>>   }; >>>   /** >>> >> >> Thanks, >> Hemant >>