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=-6.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,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 194FAC43331 for ; Thu, 2 Apr 2020 17:47:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BAFC320737 for ; Thu, 2 Apr 2020 17:47:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="WIn+vTZc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389955AbgDBRrY (ORCPT ); Thu, 2 Apr 2020 13:47:24 -0400 Received: from mail-il1-f195.google.com ([209.85.166.195]:40561 "EHLO mail-il1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732784AbgDBRrY (ORCPT ); Thu, 2 Apr 2020 13:47:24 -0400 Received: by mail-il1-f195.google.com with SMTP id j9so4485215ilr.7 for ; Thu, 02 Apr 2020 10:47:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=7tyjlIV/2N0ARSrmOSXoDfKybdDWJ1zVvs4tCYf0i/w=; b=WIn+vTZciEAII1pqjyivQ1oU/4Tql4s5w6b3N6Pj6lK28NBIzSTgE82av/gaTkujH9 uIZXyZyY9db5NPDylikYSMAgjIE2Vlum+0ND6xe6sLHa/0VfzRTBtwCjW+BZHKhxe4II rZLW4umjx7zNZVfTIa2t3LY7ePRlijW8lSsqBPA1RL/WII37a2bcZgmbEK47kyHULLNZ E9XZ1Fgf/J7I1PNLeARHk+aoVJn9LNmNKgLcO8/J3YlrTEmlEKSywJcAoUodeJZh5ryx gXY5028liMLkOmUSU8daIlKsq6sMDZs3+e2m4gPb2EFTzIK6+MjdNNXRqAhWleyGb1YS MgCQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=7tyjlIV/2N0ARSrmOSXoDfKybdDWJ1zVvs4tCYf0i/w=; b=LCFVjaMGnkFKpjsOyrPIfZ0fr1t3QvRtK+7M45L9JDZpJYrIqFOOOvUNPwC2cHxBku 8hqahrQ0L3lV3PjyZXxpvqaZOjeg0CBZsIbT3tBMzrsrjdCOaM8wbWmHMeXtbgdCtVmg 7HsQD9oQmWrpX5JrlPw8x2Z+KHXxeRXSGw8IhneRJ0GV7KP0R54+wqJahAn7Di9iXGE6 lZKgaZ2zGvj1ZWEDBPxdy0Zh19DaD7eIAL896MCwVzVKYkmuiX7EYIq3tmIDJ3ocp68k 1GcpgBCG77KRIIQ+ud/6MtIJU5Hn01JCvdr0SWcB7I9qWUoH8FH/uB1AByndqo/sSUL7 iGrw== X-Gm-Message-State: AGi0PubG4Yh+USqv/JpV4I8DxbVtnZBc51pwD0+z04sCzUqKCdIvEIwo luTAJanVjeS9cokjDr+51ZsaiC0ZwtOXP7eU6/JGSQ== X-Google-Smtp-Source: APiQypKz3Kwv9DPfJaatShj+kFJdZu0incWoyAV2P37mLvdgxzx17KnZpVbtMYlW5s5jOfrz5Y2YxVho0Dyf4uJRkzc= X-Received: by 2002:a92:8352:: with SMTP id f79mr4349489ild.58.1585849642843; Thu, 02 Apr 2020 10:47:22 -0700 (PDT) MIME-Version: 1.0 References: <1582167465-2549-1-git-send-email-sidgup@codeaurora.org> <1582167465-2549-7-git-send-email-sidgup@codeaurora.org> <20200227215940.GC20116@xps15> <1a615fcd5a5c435d1d8babe8d5c3f8c3@codeaurora.org> <20200228183832.GA23026@xps15> <050a8613cd00a84678b4478ef3387465@codeaurora.org> <64310efc-00f3-f8d8-3058-19dfbe1aa578@codeaurora.org> In-Reply-To: <64310efc-00f3-f8d8-3058-19dfbe1aa578@codeaurora.org> From: Mathieu Poirier Date: Thu, 2 Apr 2020 11:47:11 -0600 Message-ID: Subject: Re: [PATCH 6/6] remoteproc: qcom: Add notification types to SSR To: Siddharth Gupta Cc: Rishabh Bhatnagar , Ohad Ben-Cohen , tsoni@codeaurora.org, linux-arm-msm , linux-remoteproc , Linux Kernel Mailing List , Bjorn Andersson , Andy Gross , psodagud@codeaurora.org, linux-arm-kernel , linux-remoteproc-owner@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 1 Apr 2020 at 19:01, Siddharth Gupta wrote: > > On 3/9/2020 10:34 AM, Mathieu Poirier wrote: > > > On Tue, 3 Mar 2020 at 16:30, wrote: > >> On 2020-03-03 10:05, Mathieu Poirier wrote: > >>> On Mon, 2 Mar 2020 at 13:54, wrote: > >>>> On 2020-02-28 10:38, Mathieu Poirier wrote: > >>>>> On Thu, Feb 27, 2020 at 04:00:21PM -0800, rishabhb@codeaurora.org > >>>>> wrote: > >>>>>> On 2020-02-27 13:59, Mathieu Poirier wrote: > >>>>>>> On Wed, Feb 19, 2020 at 06:57:45PM -0800, Siddharth Gupta wrote: > >>>>>>>> The SSR subdevice only adds callback for the unprepare event. Add > >>>>>>>> callbacks > >>>>>>>> for unprepare, start and prepare events. The client driver for a > >>>>>>>> particular > >>>>>>>> remoteproc might be interested in knowing the status of the remoteproc > >>>>>>>> while undergoing SSR, not just when the remoteproc has finished > >>>>>>>> shutting > >>>>>>>> down. > >>>>>>>> > >>>>>>>> Signed-off-by: Siddharth Gupta > >>>>>>>> --- > >>>>>>>> drivers/remoteproc/qcom_common.c | 39 > >>>>>>>> +++++++++++++++++++++++++++++++++++---- > >>>>>>>> include/linux/remoteproc.h | 15 +++++++++++++++ > >>>>>>>> 2 files changed, 50 insertions(+), 4 deletions(-) > >>>>>>>> > >>>>>>>> diff --git a/drivers/remoteproc/qcom_common.c > >>>>>>>> b/drivers/remoteproc/qcom_common.c > >>>>>>>> index 6714f27..6f04a5b 100644 > >>>>>>>> --- a/drivers/remoteproc/qcom_common.c > >>>>>>>> +++ b/drivers/remoteproc/qcom_common.c > >>>>>>>> @@ -183,9 +183,9 @@ EXPORT_SYMBOL_GPL(qcom_remove_smd_subdev); > >>>>>>>> * > >>>>>>>> * Returns pointer to srcu notifier head on success, ERR_PTR on > >>>>>>>> failure. > >>>>>>>> * > >>>>>>>> - * This registers the @notify function as handler for restart > >>>>>>>> notifications. As > >>>>>>>> - * remote processors are stopped this function will be called, with > >>>>>>>> the rproc > >>>>>>>> - * pointer passed as a parameter. > >>>>>>>> + * This registers the @notify function as handler for > >>>>>>>> powerup/shutdown > >>>>>>>> + * notifications. This function will be invoked inside the > >>>>>>>> callbacks registered > >>>>>>>> + * for the ssr subdevice, with the rproc pointer passed as a > >>>>>>>> parameter. > >>>>>>>> */ > >>>>>>>> void *qcom_register_ssr_notifier(struct rproc *rproc, struct > >>>>>>>> notifier_block *nb) > >>>>>>>> { > >>>>>>>> @@ -227,11 +227,39 @@ int qcom_unregister_ssr_notifier(void *notify, > >>>>>>>> struct notifier_block *nb) > >>>>>>>> } > >>>>>>>> EXPORT_SYMBOL_GPL(qcom_unregister_ssr_notifier); > >>>>>>>> > >>>>>>>> +static int ssr_notify_prepare(struct rproc_subdev *subdev) > >>>>>>>> +{ > >>>>>>>> + struct qcom_rproc_ssr *ssr = to_ssr_subdev(subdev); > >>>>>>>> + > >>>>>>>> + srcu_notifier_call_chain(ssr->rproc_notif_list, > >>>>>>>> + RPROC_BEFORE_POWERUP, (void *)ssr->name); > >>>>>>>> + return 0; > >>>>>>>> +} > >>>>>>>> + > >>>>>>>> +static int ssr_notify_start(struct rproc_subdev *subdev) > >>>>>>>> +{ > >>>>>>>> + struct qcom_rproc_ssr *ssr = to_ssr_subdev(subdev); > >>>>>>>> + > >>>>>>>> + srcu_notifier_call_chain(ssr->rproc_notif_list, > >>>>>>>> + RPROC_AFTER_POWERUP, (void *)ssr->name); > >>>>>>>> + return 0; > >>>>>>>> +} > >>>>>>>> + > >>>>>>>> +static void ssr_notify_stop(struct rproc_subdev *subdev, bool > >>>>>>>> crashed) > >>>>>>>> +{ > >>>>>>>> + struct qcom_rproc_ssr *ssr = to_ssr_subdev(subdev); > >>>>>>>> + > >>>>>>>> + srcu_notifier_call_chain(ssr->rproc_notif_list, > >>>>>>>> + RPROC_BEFORE_SHUTDOWN, (void *)ssr->name); > >>>>>>>> +} > >>>>>>>> + > >>>>>>>> + > >>>>>>>> static void ssr_notify_unprepare(struct rproc_subdev *subdev) > >>>>>>>> { > >>>>>>>> struct qcom_rproc_ssr *ssr = to_ssr_subdev(subdev); > >>>>>>>> > >>>>>>>> - srcu_notifier_call_chain(ssr->rproc_notif_list, 0, (void > >>>>>>>> *)ssr->name); > >>>>>>>> + srcu_notifier_call_chain(ssr->rproc_notif_list, > >>>>>>>> + RPROC_AFTER_SHUTDOWN, (void *)ssr->name); > >>>>>>>> } > >>>>>>>> > >>>>>>>> /** > >>>>>>>> @@ -248,6 +276,9 @@ void qcom_add_ssr_subdev(struct rproc *rproc, > >>>>>>>> struct qcom_rproc_ssr *ssr, > >>>>>>>> { > >>>>>>>> ssr->name = ssr_name; > >>>>>>>> ssr->subdev.name = kstrdup("ssr_notifs", GFP_KERNEL); > >>>>>>>> + ssr->subdev.prepare = ssr_notify_prepare; > >>>>>>>> + ssr->subdev.start = ssr_notify_start; > >>>>>>>> + ssr->subdev.stop = ssr_notify_stop; > >>>>>>> Now that I have a better understanding of what this patchset is doing, I > >>>>>>> realise > >>>>>>> my comments in patch 04 won't work. To differentiate the subdevs of an > >>>>>>> rproc I > >>>>>>> suggest to wrap them in a generic structure with a type and an enum. > >>>>>>> That way > >>>>>>> you can differenciate between subdevices without having to add to the > >>>>>>> core. > > While creating a new revision of the patchset we tried to implement > this, but a similar issue comes > up. If at a later point we wish to utilize the functionality of some > common subdevice (not the case > right now, but potentially), we might run into a similar problem of > accessing illegal memory using > container_of. I think it might be a better idea to introduce the name in > the subdevice structure over > having a potential security bug. What do you think? I trust that you have given this an honest try but found potential problems that I can't foresee due to the lack of insight on your operating environment. Please move forward with the addition of a new "name" field to the rproc_subdev structure. > > Thanks, > Siddharth > > >>>>>> Ok. I can try that. > >>>>>>> That being said, I don't understand what patches 5 and 6 are doing... > >>>>>>> Registering with the global ssr_notifiers allowed to gracefully shutdown > >>>>>>> all the > >>>>>>> MCUs in the system when one of them would go down. But now that we are > >>>>>>> using > >>>>>>> the notifier on a per MCU, I really don't see why each subdev couldn't > >>>>>>> implement > >>>>>>> the right prepare/start/stop functions. > >>>>>>> > >>>>>>> Am I missing something here? > >>>>>> We only want kernel clients to be notified when the Remoteproc they > >>>>>> are > >>>>>> interested > >>>>>> in changes state. For e.g. audio kernel driver should be notified when > >>>>>> audio > >>>>>> processor goes down but it does not care about any other remoteproc. > >>>>>> If you are suggesting that these kernel clients be added as subdevices > >>>>>> then > >>>>>> we will end up having many subdevices registered to each remoteproc. > >>>>>> So we > >>>>>> implemented a notifier chain per Remoteproc. This keeps the SSR > >>>>>> notifications as > >>>>>> the subdevice per remoteproc, and all interested clients can register > >>>>>> to it. > >>>>> It seems like I am missing information... Your are referring to > >>>>> "kernel > >>>>> clients" and as such I must assume some drivers that are not part of > >>>>> the > >>>>> remoteproc/rpmsg subsystems are calling qcom_register_ssr_notifier(). > >>>>> I must > >>>> Yes these are not part of remoteproc framework and they will register > >>>> for notifications. > >>>>> also assume these drivers (or that functionality) are not yet upsream > >>>>> because > >>>>> all I can see calling qcom_register_ssr_notifier() is > >>>>> qcom_glink_ssr_probe(). > >>>> Correct.These are not upstreamed. > >>> Ok, things are starting to make sense. > >>> > >>>>> Speaking of which, what is the role of the qcom_glink_ssr_driver? Is > >>>>> the glink > >>>>> device that driver is handling the same as the glink device registed in > >>>>> adsp_probe() and q6v5_probe()? > >>>> glink ssr driver will send out notifications to remoteprocs that have > >>>> opened the > >>>> "glink_ssr" channel that some subsystem has gone down or booted up. > >>>> This > >>>> helps notify > >>>> neighboring subsystems about change in state of any other subsystem. > >>> I am still looking for an answer to my second question. > >> Yes its the subdevice of the glink device that is registered in > >> adsp_probe. > >> It uses the "glink_ssr" glink channel. > > Since this is confining events to a single MCU, I was mostly worried > > about opening the "glink_ssr" channel for nothing but taking a step > > back and thinking further on this, there might be other purposes for > > the channel than only receiving notifications of other MCUs in the > > system going down. > > > > Please spin off a new revision of this set and I will take another look. > > > > Thanks, > > Mathieu > > > >>>>>>> > >>>>>>>> ssr->subdev.unprepare = ssr_notify_unprepare; > >>>>>>>> ssr->rproc_notif_list = kzalloc(sizeof(struct srcu_notifier_head), > >>>>>>>> GFP_KERNEL); > >>>>>>>> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h > >>>>>>>> index e2f60cc..4be4478 100644 > >>>>>>>> --- a/include/linux/remoteproc.h > >>>>>>>> +++ b/include/linux/remoteproc.h > >>>>>>>> @@ -449,6 +449,21 @@ struct rproc_dump_segment { > >>>>>>>> }; > >>>>>>>> > >>>>>>>> /** > >>>>>>>> + * enum rproc_notif_type - Different stages of remoteproc > >>>>>>>> notifications > >>>>>>>> + * @RPROC_BEFORE_SHUTDOWN: unprepare stage of remoteproc > >>>>>>>> + * @RPROC_AFTER_SHUTDOWN: stop stage of remoteproc > >>>>>>>> + * @RPROC_BEFORE_POWERUP: prepare stage of remoteproc > >>>>>>>> + * @RPROC_AFTER_POWERUP: start stage of remoteproc > >>>>>>>> + */ > >>>>>>>> +enum rproc_notif_type { > >>>>>>>> + RPROC_BEFORE_SHUTDOWN, > >>>>>>>> + RPROC_AFTER_SHUTDOWN, > >>>>>>>> + RPROC_BEFORE_POWERUP, > >>>>>>>> + RPROC_AFTER_POWERUP, > >>>>>>>> + RPROC_MAX > >>>>>>>> +}; > >>>>>>>> + > >>>>>>>> +/** > >>>>>>>> * struct rproc - represents a physical remote processor device > >>>>>>>> * @node: list node of this rproc object > >>>>>>>> * @domain: iommu domain > >>>>>>>> -- > >>>>>>>> Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > >>>>>>>> a Linux Foundation Collaborative Project > >>>>>>>> > >>>>>>>> _______________________________________________ > >>>>>>>> linux-arm-kernel mailing list > >>>>>>>> linux-arm-kernel@lists.infradead.org > >>>>>>>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > >>>> _______________________________________________ > >>>> linux-arm-kernel mailing list > >>>> linux-arm-kernel@lists.infradead.org > >>>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel