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=-6.8 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,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 16196C55189 for ; Thu, 23 Apr 2020 00:53:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E2D462075A for ; Thu, 23 Apr 2020 00:53:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="ySUaw2hG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726343AbgDWAxe (ORCPT ); Wed, 22 Apr 2020 20:53:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57952 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726008AbgDWAxc (ORCPT ); Wed, 22 Apr 2020 20:53:32 -0400 Received: from mail-pg1-x542.google.com (mail-pg1-x542.google.com [IPv6:2607:f8b0:4864:20::542]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AAF09C03C1AD for ; Wed, 22 Apr 2020 17:53:30 -0700 (PDT) Received: by mail-pg1-x542.google.com with SMTP id r4so2009724pgg.4 for ; Wed, 22 Apr 2020 17:53:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=zaMslWpZYQE1cPZBGYasv3MNuzEHzc5rvrYAj1cFoUo=; b=ySUaw2hGK318opjQ7onBQV22y1HgRSTjLRyOzUlAEquw0O+gd8L1YWex6Qgpe+AdcQ 46stp24stM2UJ92PQ1FL+2dS5s6HuekSdS3LbXGvEsAu2B/hI5BfLUeIHQn31LMgfChK AUGpnLVyyJUsDKwIe3p2HH2kw/bcJpJJ4lcCSTw32V5b/E5emMlu2UHA5w0d1O/M4Rkz fSt9z71hSkp0izZGC0kHNGEjs78AeWMHD2YZQ/zjXIKDt8FBHnLAkCiTs4wFE5lYQ6Do w5gxXcg6jH3F369W/tTqbYCcekwqbh5iK7F6O6BIoDiIJ068LnPJuieSQBQfSDmKNZhq UJGw== 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; bh=zaMslWpZYQE1cPZBGYasv3MNuzEHzc5rvrYAj1cFoUo=; b=tgieM32cMgGTOpA/Dpq9mRXOH51A8y1S/5dmQknWdTPGX7TgPU/kHbywrHTefjajUl vDnBsoMhwFNLuEfxv5n1SoocaBrcwAn9RWq9sydTyMt6uCWiC4Cehpqs1UFHnMs2bCI2 XifohPsqsD/qJ8OCUBh6XReH7erZ5FegTKiJqzY86k1VdpiGMRu0l4ay0BXQrneQcbc4 hspFtI9EuNjrfcvITVl5Yb9EhDBcnKSsLZp9XkHfBKzLhfiLff/flaQn39atn6WY0gR3 P3KEC6L/E6QxxUd/spLNuo9/TpjxlDhaSVKf6wI+mkHn9rqNCrt+0GSaTVbKqp2bh+ro ZwGg== X-Gm-Message-State: AGi0Pub++y7jQ9TkVGDaZVfo1c8ID6MiIcNC/6zhFso+cC6MzGCxSkE1 +Fvv08sOC/4O/tOOAGwlwIYb/jv5dQE= X-Google-Smtp-Source: APiQypJKqfkEySumffvFRj+2CM+bSCQ6VLwZF4WDXzR4yhTUrBP6wD8QX9LvzHwkW1lbKYzs+jBYEg== X-Received: by 2002:aa7:9904:: with SMTP id z4mr1271870pff.38.1587603209814; Wed, 22 Apr 2020 17:53:29 -0700 (PDT) Received: from builder.lan (104-188-17-28.lightspeed.sndgca.sbcglobal.net. [104.188.17.28]) by smtp.gmail.com with ESMTPSA id e7sm727392pfh.161.2020.04.22.17.53.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Apr 2020 17:53:29 -0700 (PDT) Date: Wed, 22 Apr 2020 17:53:56 -0700 From: Bjorn Andersson To: Siddharth Gupta Cc: agross@kernel.org, ohad@wizery.com, linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, tsoni@codeaurora.org, psodagud@codeaurora.org, rishabhb@codeaurora.org Subject: Re: [PATCH v2 5/6] remoteproc: qcom: Add per subsystem SSR notification Message-ID: <20200423005356.GL1868936@builder.lan> References: <1586389003-26675-1-git-send-email-sidgup@codeaurora.org> <1586389003-26675-6-git-send-email-sidgup@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1586389003-26675-6-git-send-email-sidgup@codeaurora.org> Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Wed 08 Apr 16:36 PDT 2020, Siddharth Gupta wrote: > Currently there is a global notification chain which is called whenever any > remoteproc shuts down. This leads to all the listeners being notified, and > is not an optimal design as kernel drivers might only be interested in > listening to notifications from a particular remoteproc. Create an > individual notifier chain for every SSR subdevice, and modify the > notification registration API to include the remoteproc struct as an > argument. Update the existing user of the registration API to get the > phandle of the remoteproc dt node to register for SSR notifications. > > Signed-off-by: Rishabh Bhatnagar > Signed-off-by: Siddharth Gupta > --- > drivers/remoteproc/qcom_common.c | 49 +++++++++++++++++++++++++++-------- > drivers/remoteproc/qcom_common.h | 1 + > drivers/soc/qcom/glink_ssr.c | 20 ++++++++++++-- > include/linux/remoteproc/qcom_rproc.h | 17 ++++++++---- > 4 files changed, 69 insertions(+), 18 deletions(-) > > diff --git a/drivers/remoteproc/qcom_common.c b/drivers/remoteproc/qcom_common.c > index 1d2351b..56b0c3e 100644 > --- a/drivers/remoteproc/qcom_common.c > +++ b/drivers/remoteproc/qcom_common.c > @@ -23,8 +23,6 @@ > #define to_smd_subdev(d) container_of(d, struct qcom_rproc_subdev, subdev) > #define to_ssr_subdev(d) container_of(d, struct qcom_rproc_ssr, subdev) > > -static BLOCKING_NOTIFIER_HEAD(ssr_notifiers); > - > static int glink_subdev_start(struct rproc_subdev *subdev) > { > struct qcom_rproc_glink *glink = to_glink_subdev(subdev); > @@ -180,27 +178,52 @@ EXPORT_SYMBOL_GPL(qcom_remove_smd_subdev); > > /** > * qcom_register_ssr_notifier() - register SSR notification handler > + * @rproc: pointer to the remoteproc structure > * @nb: notifier_block to notify for restart notifications > * > - * Returns 0 on success, negative errno on failure. > + * Returns pointer to srcu notifier head on success, ERR_PTR on failure. > * > - * This register the @notify function as handler for restart notifications. As > - * remote processors are stopped this function will be called, with the SSR > - * name passed as a parameter. > + * 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. > */ > -int qcom_register_ssr_notifier(struct notifier_block *nb) > +void *qcom_register_ssr_notifier(struct rproc *rproc, struct notifier_block *nb) > { > - return blocking_notifier_chain_register(&ssr_notifiers, nb); > + struct rproc_subdev *subdev; > + struct qcom_rproc_ssr *ssr; > + int ret; > + > + if (!rproc) > + return ERR_PTR(-EINVAL); > + > + mutex_lock(&rproc->lock); > + list_for_each_entry(subdev, &rproc->subdevs, node) { I would prefer that we don't touch the lock or subdevs list outside of the remoteproc core. > + ret = strcmp(subdev->name, "ssr_notifs"); > + if (!ret) > + break; > + } > + mutex_unlock(&rproc->lock); > + if (ret) > + return ERR_PTR(-ENOENT); > + > + ssr = to_ssr_subdev(subdev); > + srcu_notifier_chain_register(ssr->rproc_notif_list, nb); Adding the notifier to an existing ssr_subdev means that any client driver that is interested in notification about a remoteproc coming and going will need to be registered (typically probed) after the remoteproc driver. I presume this would be handled by probe deferring on rproc_get_by_phandle(), but I'm concerned that this will cause unnecessary probe deferral. But more importantly, it wouldn't allow for the remoteproc driver to be unloaded and loaded again (as that would be a new notifier list). So I think you should carry a global list of "watchers" and upon subdev events you can match entries in this list based on either struct of_node or perhaps by ssr_name? > + > + return ssr->rproc_notif_list; > } > EXPORT_SYMBOL_GPL(qcom_register_ssr_notifier); > > /** > * qcom_unregister_ssr_notifier() - unregister SSR notification handler > + * @notify: pointer to srcu notifier head > * @nb: notifier_block to unregister > */ > -void qcom_unregister_ssr_notifier(struct notifier_block *nb) > +int qcom_unregister_ssr_notifier(void *notify, struct notifier_block *nb) > { > - blocking_notifier_chain_unregister(&ssr_notifiers, nb); > + if (!notify) > + return -EINVAL; > + > + return srcu_notifier_chain_unregister(notify, nb); > } > EXPORT_SYMBOL_GPL(qcom_unregister_ssr_notifier); > > @@ -208,7 +231,7 @@ static void ssr_notify_unprepare(struct rproc_subdev *subdev) > { > struct qcom_rproc_ssr *ssr = to_ssr_subdev(subdev); > > - blocking_notifier_call_chain(&ssr_notifiers, 0, (void *)ssr->name); > + srcu_notifier_call_chain(ssr->rproc_notif_list, 0, (void *)ssr->name); > } > > /** > @@ -226,6 +249,9 @@ 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.unprepare = ssr_notify_unprepare; > + ssr->rproc_notif_list = kzalloc(sizeof(struct srcu_notifier_head), > + GFP_KERNEL); > + srcu_init_notifier_head(ssr->rproc_notif_list); > > rproc_add_subdev(rproc, &ssr->subdev); > } > @@ -239,6 +265,7 @@ EXPORT_SYMBOL_GPL(qcom_add_ssr_subdev); > void qcom_remove_ssr_subdev(struct rproc *rproc, struct qcom_rproc_ssr *ssr) > { > kfree(ssr->subdev.name); > + kfree(ssr->rproc_notif_list); > rproc_remove_subdev(rproc, &ssr->subdev); > } > EXPORT_SYMBOL_GPL(qcom_remove_ssr_subdev); > diff --git a/drivers/remoteproc/qcom_common.h b/drivers/remoteproc/qcom_common.h > index 58de71e..7792691 100644 > --- a/drivers/remoteproc/qcom_common.h > +++ b/drivers/remoteproc/qcom_common.h > @@ -27,6 +27,7 @@ struct qcom_rproc_subdev { > struct qcom_rproc_ssr { > struct rproc_subdev subdev; > > + struct srcu_notifier_head *rproc_notif_list; > const char *name; > }; > > diff --git a/drivers/soc/qcom/glink_ssr.c b/drivers/soc/qcom/glink_ssr.c > index d7babe3..2b39683 100644 > --- a/drivers/soc/qcom/glink_ssr.c > +++ b/drivers/soc/qcom/glink_ssr.c > @@ -7,6 +7,7 @@ > #include > #include > #include > +#include > #include > #include > > @@ -49,6 +50,7 @@ struct glink_ssr { > struct rpmsg_endpoint *ept; > > struct notifier_block nb; > + void *notifier_head; > > u32 seq_num; > struct completion completion; > @@ -112,6 +114,7 @@ static int qcom_glink_ssr_notify(struct notifier_block *nb, unsigned long event, > static int qcom_glink_ssr_probe(struct rpmsg_device *rpdev) > { > struct glink_ssr *ssr; > + struct rproc *rproc; > > ssr = devm_kzalloc(&rpdev->dev, sizeof(*ssr), GFP_KERNEL); > if (!ssr) > @@ -125,14 +128,27 @@ static int qcom_glink_ssr_probe(struct rpmsg_device *rpdev) > > dev_set_drvdata(&rpdev->dev, ssr); > > - return qcom_register_ssr_notifier(&ssr->nb); > + rproc = rproc_get_by_child(&rpdev->dev); As we discussed in our meeting offline earlier today, not all glink_ssr instances has a remoteproc ancestor. After going back and forth on how to handle this I posted below series: https://lore.kernel.org/linux-arm-msm/20200423003736.2027371-1-bjorn.andersson@linaro.org/T/#t With this we are flexible to tie the ssr_subdev API to remoteproc instances... Regards, Bjorn