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=-8.3 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,USER_AGENT_SANE_1 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 B6B1EC4724C for ; Wed, 6 May 2020 07:51:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 990B6206D5 for ; Wed, 6 May 2020 07:51:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=st.com header.i=@st.com header.b="TmPt9OdW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728464AbgEFHve (ORCPT ); Wed, 6 May 2020 03:51:34 -0400 Received: from mx07-00178001.pphosted.com ([62.209.51.94]:16096 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728280AbgEFHvd (ORCPT ); Wed, 6 May 2020 03:51:33 -0400 Received: from pps.filterd (m0046668.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 0467lFIq007704; Wed, 6 May 2020 09:51:23 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=st.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=STMicroelectronics; bh=EbDaiplmg1Q7XCQNBmWnN701UTyThBLfH9pJeg2q7Xw=; b=TmPt9OdWjeDx2Qy8hrSQ8t8yMu9/hqJ6WGYk47/V6GVLv/itHMS7cEqt27Tirk6ry9mc dTMKumNGAGA6utdhiSGSrVlshNekl3Qavw2cssPaec5ujaLVGMjGz7/6BOkDzw/xqRZM 9SEcNJ+n8qPoFxYt0Fk4bcQ8xmIz4RuwW8tNbvJZY9mh9NcpCaK29ZYc/WeLZcXebFZp NbkG0hF53LniJlvELWcscLjLgKr3YF1/s7OTuOmwBYmkxZD4HAjwY/bdmYHMMATaGAGi TwVMPQVAYTI/6u8B7H/mDHJvPNIb+0PKipw4al9BJdznWq2is7rya5q+Zk2wR9losiQd 6w== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 30rxb24mwf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 06 May 2020 09:51:23 +0200 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 09EED10002A; Wed, 6 May 2020 09:51:23 +0200 (CEST) Received: from Webmail-eu.st.com (sfhdag3node1.st.com [10.75.127.7]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id ED5FE2A6CD9; Wed, 6 May 2020 09:51:22 +0200 (CEST) Received: from lmecxl0889.tpe.st.com (10.75.127.49) by SFHDAG3NODE1.st.com (10.75.127.7) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 6 May 2020 09:51:21 +0200 Subject: Re: [PATCH v3 10/14] remoteproc: Deal with synchronisation when shutting down To: Mathieu Poirier CC: , , , , , , , References: <20200424200135.28825-1-mathieu.poirier@linaro.org> <20200424200135.28825-11-mathieu.poirier@linaro.org> <20200430202312.GE17031@xps15> <04b8f860-2b01-7e4f-cdea-08a3cf8af26c@st.com> <20200505220327.GB18333@xps15> From: Arnaud POULIQUEN Message-ID: <2aac2d9e-bd2f-d60a-a0ac-3b8541a9cde2@st.com> Date: Wed, 6 May 2020 09:51:20 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200505220327.GB18333@xps15> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.75.127.49] X-ClientProxiedBy: SFHDAG3NODE2.st.com (10.75.127.8) To SFHDAG3NODE1.st.com (10.75.127.7) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.676 definitions=2020-05-06_02:2020-05-04,2020-05-06 signatures=0 Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On 5/6/20 12:03 AM, Mathieu Poirier wrote: > On Mon, May 04, 2020 at 01:34:43PM +0200, Arnaud POULIQUEN wrote: >> >> >> On 4/30/20 10:23 PM, Mathieu Poirier wrote: >>> On Wed, Apr 29, 2020 at 10:19:49AM +0200, Arnaud POULIQUEN wrote: >>>> >>>> >>>> On 4/24/20 10:01 PM, Mathieu Poirier wrote: >>>>> The remoteproc core must not allow function rproc_shutdown() to >>>>> proceed if currently synchronising with a remote processor and >>>>> the synchronisation operations of that remote processor does not >>>>> support it. Also part of the process is to set the synchronisation >>>>> flag so that the remoteproc core can make the right decisions when >>>>> restarting the system. >>>>> >>>>> Signed-off-by: Mathieu Poirier >>>>> --- >>>>> drivers/remoteproc/remoteproc_core.c | 32 ++++++++++++++++++++++++ >>>>> drivers/remoteproc/remoteproc_internal.h | 7 ++++++ >>>>> 2 files changed, 39 insertions(+) >>>>> >>>>> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c >>>>> index 3a84a38ba37b..48afa1f80a8f 100644 >>>>> --- a/drivers/remoteproc/remoteproc_core.c >>>>> +++ b/drivers/remoteproc/remoteproc_core.c >>>>> @@ -1849,6 +1849,27 @@ int rproc_boot(struct rproc *rproc) >>>>> } >>>>> EXPORT_SYMBOL(rproc_boot); >>>>> >>>>> +static bool rproc_can_shutdown(struct rproc *rproc) >>>>> +{ >>>>> + /* >>>>> + * The remoteproc core is the lifecycle manager, no problem >>>>> + * calling for a shutdown. >>>>> + */ >>>>> + if (!rproc_needs_syncing(rproc)) >>>>> + return true; >>>>> + >>>>> + /* >>>>> + * The remoteproc has been loaded by another entity (as per above >>>>> + * condition) and the platform code has given us the capability >>>>> + * of stopping it. >>>>> + */ >>>>> + if (rproc->sync_ops->stop) >>>>> + return true; >>>> >>>> This means that if rproc->sync_ops->stop is null rproc_stop_subdevices will not >>>> be called? seems not symmetric with the start sequence. >>> >>> If rproc->sync_ops->stop is not provided then the remoteproc core can't stop the >>> remote processor at all after it has synchronised with it. If a usecase >>> requires some kind of soft reset then a stop() function that uses a mailbox >>> notification or some other mechanism can be provided to tell the remote >>> processor to put itself back in startup mode again. >>> >>> Is this fine with you or there is still something I don't get? >> >> My point here is more around the subdevices. But perhaps i missed something... >> >> In rproc_start rproc_start_subdevices is called, even if sync_start is null. > > Here I'll take that you mean sync_ops::start() > >> But in rproc_shutdown rproc_stop is not called, if sync_ops->stop is null. >> So rproc_stop_subdevices is not called in this case. > > Correct. I am pretty sure some people don't want the remoteproc core to be able > to do anything other than synchronise with a remote processor, be it at boot > time or when the remote processor has crashed. > > I can also see scenarios where people want to be able to start and stop > subdevices from the remoteproc core, but _not_ power cycle the remote processor. > In such cases the sync_ops::stop() should be some kind of notification telling > the remote processor to put itself back in initialisation mode and > sync_flags.after_stop should be set to true. > >> Then if sync_flags.after_stop is false, it looks like that something will go wrong >> at next start. > > If sync_ops::stop is NULL then the value of sync_flags.after_stop becomes > irrelevant because that state can't be reached. Let me know if you found a > condition where this isn't the case and I will correct it. The only condition i have in mind is that the sync_ops::stop() can not implemented in platform driver, just because nothing to do. But i don't know if it is a realistic use case and having a dummy stop function looks to me acceptable in this particular use case. This triggers me another comment :) the rproc_ops struct description is relevant for the "normal" ops but not adapted for the sync_ops. For instance the start & stop are mandatory for ops, optional for sync_ops As this description is a reference (at least for me) to determine optional and mandatory ops would be useful to update it. Regards, Arnaud > >> >>> >>>> Probably not useful to test it here as condition is already handled in rproc_stop_device... >>>> >>>> Regards >>>> Arnaud >>>>> + >>>>> + /* Any other condition should not be allowed */ >>>>> + return false; >>>>> +} >>>>> + >>>>> /** >>>>> * rproc_shutdown() - power off the remote processor >>>>> * @rproc: the remote processor >>>>> @@ -1879,6 +1900,9 @@ void rproc_shutdown(struct rproc *rproc) >>>>> return; >>>>> } >>>>> >>>>> + if (!rproc_can_shutdown(rproc)) >>>>> + goto out; >>>>> + >>>>> /* if the remote proc is still needed, bail out */ >>>>> if (!atomic_dec_and_test(&rproc->power)) >>>>> goto out; >>>>> @@ -1898,6 +1922,14 @@ void rproc_shutdown(struct rproc *rproc) >>>>> kfree(rproc->cached_table); >>>>> rproc->cached_table = NULL; >>>>> rproc->table_ptr = NULL; >>>>> + >>>>> + /* >>>>> + * The remote processor has been switched off - tell the core what >>>>> + * operation to use from hereon, i.e whether an external entity will >>>>> + * reboot the remote processor or it is now the remoteproc core's >>>>> + * responsability. >>>>> + */ >>>>> + rproc_set_sync_flag(rproc, RPROC_SYNC_STATE_SHUTDOWN); >>>>> out: >>>>> mutex_unlock(&rproc->lock); >>>>> } >>>>> diff --git a/drivers/remoteproc/remoteproc_internal.h b/drivers/remoteproc/remoteproc_internal.h >>>>> index 61500981155c..7dcc0a26892b 100644 >>>>> --- a/drivers/remoteproc/remoteproc_internal.h >>>>> +++ b/drivers/remoteproc/remoteproc_internal.h >>>>> @@ -27,6 +27,9 @@ struct rproc_debug_trace { >>>>> /* >>>>> * enum rproc_sync_states - remote processsor sync states >>>>> * >>>>> + * @RPROC_SYNC_STATE_SHUTDOWN state to use after the remoteproc core >>>>> + * has shutdown (rproc_shutdown()) the >>>>> + * remote processor. >>>>> * @RPROC_SYNC_STATE_CRASHED state to use after the remote processor >>>>> * has crashed but has not been recovered by >>>>> * the remoteproc core yet. >>>>> @@ -36,6 +39,7 @@ struct rproc_debug_trace { >>>>> * operation to use. >>>>> */ >>>>> enum rproc_sync_states { >>>>> + RPROC_SYNC_STATE_SHUTDOWN, >>>>> RPROC_SYNC_STATE_CRASHED, >>>>> }; >>>>> >>>>> @@ -43,6 +47,9 @@ static inline void rproc_set_sync_flag(struct rproc *rproc, >>>>> enum rproc_sync_states state) >>>>> { >>>>> switch (state) { >>>>> + case RPROC_SYNC_STATE_SHUTDOWN: >>>>> + rproc->sync_with_rproc = rproc->sync_flags.after_stop; >>>>> + break; >>>>> case RPROC_SYNC_STATE_CRASHED: >>>>> rproc->sync_with_rproc = rproc->sync_flags.after_crash; >>>>> break; >>>>>