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Mon, 04 May 2020 13:58:03 +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 DCE8010002A; Mon, 4 May 2020 13:58:02 +0200 (CEST) Received: from Webmail-eu.st.com (sfhdag3node1.st.com [10.75.127.7]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id C915A2BBABC; Mon, 4 May 2020 13:58:02 +0200 (CEST) Received: from lmecxl0889.tpe.st.com (10.75.127.50) by SFHDAG3NODE1.st.com (10.75.127.7) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Mon, 4 May 2020 13:58:01 +0200 Subject: Re: [PATCH v3 12/14] remoteproc: Introducing function rproc_set_state_machine() To: Mathieu Poirier CC: , , , , , , , References: <20200424200135.28825-1-mathieu.poirier@linaro.org> <20200424200135.28825-13-mathieu.poirier@linaro.org> <20200430204233.GB18004@xps15> From: Arnaud POULIQUEN Message-ID: <842d64d8-832a-cc4c-cbe1-dbd4654fcdd5@st.com> Date: Mon, 4 May 2020 13:57:59 +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: <20200430204233.GB18004@xps15> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.75.127.50] X-ClientProxiedBy: SFHDAG8NODE3.st.com (10.75.127.24) 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=2020-05-04_07:2020-05-04,2020-05-04 signatures=0 Sender: linux-remoteproc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-remoteproc@vger.kernel.org On 4/30/20 10:42 PM, Mathieu Poirier wrote: > On Wed, Apr 29, 2020 at 11:22:28AM +0200, Arnaud POULIQUEN wrote: >> >> >> On 4/24/20 10:01 PM, Mathieu Poirier wrote: >>> Introducting function rproc_set_state_machine() to add >>> operations and a set of flags to use when synchronising with >>> a remote processor. >>> >>> Signed-off-by: Mathieu Poirier >>> --- >>> drivers/remoteproc/remoteproc_core.c | 54 ++++++++++++++++++++++++ >>> drivers/remoteproc/remoteproc_internal.h | 6 +++ >>> include/linux/remoteproc.h | 3 ++ >>> 3 files changed, 63 insertions(+) >>> >>> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c >>> index 48afa1f80a8f..5c48714e8702 100644 >>> --- a/drivers/remoteproc/remoteproc_core.c >>> +++ b/drivers/remoteproc/remoteproc_core.c >>> @@ -2065,6 +2065,59 @@ int devm_rproc_add(struct device *dev, struct rproc *rproc) >>> } >>> EXPORT_SYMBOL(devm_rproc_add); >>> >>> +/** >>> + * rproc_set_state_machine() - Set a synchronisation ops and set of flags >>> + * to use with a remote processor >>> + * @rproc: The remote processor to work with >>> + * @sync_ops: The operations to use when synchronising with a remote >>> + * processor >>> + * @sync_flags: The flags to use when deciding if the remoteproc core >>> + * should be synchronising with a remote processor >>> + * >>> + * Returns 0 on success, an error code otherwise. >>> + */ >>> +int rproc_set_state_machine(struct rproc *rproc, >>> + const struct rproc_ops *sync_ops, >>> + struct rproc_sync_flags sync_flags) >> >> So this API should be called by platform driver only in case of synchronization >> support, right? > > Correct > >> In this case i would rename it as there is also a state machine in "normal" boot >> proposal: rproc_set_sync_machine or rproc_set_sync_state_machine > > That is a valid observation - rproc_set_sync_state_machine() sounds descriptive > enough for me. > >> >>> +{ >>> + if (!rproc || !sync_ops) >>> + return -EINVAL; >>> + >>> + /* >>> + * No point in going further if we never have to synchronise with >>> + * the remote processor. >>> + */ >>> + if (!sync_flags.on_init && >>> + !sync_flags.after_stop && !sync_flags.after_crash) >>> + return 0; >>> + >>> + /* >>> + * Refuse to go further if remoteproc operations have been allocated >>> + * but they will never be used. >>> + */ >>> + if (rproc->ops && sync_flags.on_init && >>> + sync_flags.after_stop && sync_flags.after_crash) >>> + return -EINVAL; >>> + >>> + /* >>> + * Don't allow users to set this more than once to avoid situations >>> + * where the remote processor can't be recovered. >>> + */ >>> + if (rproc->sync_ops) >>> + return -EINVAL; >>> + >>> + rproc->sync_ops = kmemdup(sync_ops, sizeof(*sync_ops), GFP_KERNEL); >>> + if (!rproc->sync_ops) >>> + return -ENOMEM; >>> + >>> + rproc->sync_flags = sync_flags; >>> + /* Tell the core what to do when initialising */ >>> + rproc_set_sync_flag(rproc, RPROC_SYNC_STATE_INIT); >> >> Is there a use case where sync_flags.on_init is false and other flags are true? > > I haven't seen one yet, which doesn't mean it doesn't exist or won't in the > future. I wanted to make this as flexible as possible. I started with the idea > of making synchronisation at initialisation time implicit if > rproc_set_state_machine() is called but I know it is only a matter of time > before people come up with some exotic use case where .on_init is false. So having on_init false but after_crash && after_stop true, means loading the firmware on first start, and the synchronize with it, right? Yes probably could be an exotic valid use case. :) > >> >> Look like on_init is useless and should not be exposed to the platform driver. >> Or comments are missing to explain the usage of it vs the other flags. > > Comments added in remoteproc_internal.h and the new section in > Documentation/remoteproc.txt aren't sufficient? Can you give me a hint as to > what you think is missing? IMO something is quite confusing... On one side on_init can be set to false. But on the other side the flag is set by call rproc_set_state_machine. In Documentation/remoteproc.txt rproc_set_state_machine description is: "This function should be called for cases where the remote processor has been started by another entity, be it a boot loader or trusted environment, and the remoteproc core is to synchronise with the remote processor rather then boot it." So how on_init could be false if "the remote processor has been started by another entity"? Regards, Arnaud > >> >> Regards, >> Arnaud >> >>> + >>> + return 0; >>> +} >>> +EXPORT_SYMBOL(rproc_set_state_machine); >>> + >>> /** >>> * rproc_type_release() - release a remote processor instance >>> * @dev: the rproc's device >>> @@ -2088,6 +2141,7 @@ static void rproc_type_release(struct device *dev) >>> kfree_const(rproc->firmware); >>> kfree_const(rproc->name); >>> kfree(rproc->ops); >>> + kfree(rproc->sync_ops); >>> kfree(rproc); >>> } >>> >>> diff --git a/drivers/remoteproc/remoteproc_internal.h b/drivers/remoteproc/remoteproc_internal.h >>> index 7dcc0a26892b..c1a293a37c78 100644 >>> --- a/drivers/remoteproc/remoteproc_internal.h >>> +++ b/drivers/remoteproc/remoteproc_internal.h >>> @@ -27,6 +27,8 @@ struct rproc_debug_trace { >>> /* >>> * enum rproc_sync_states - remote processsor sync states >>> * >>> + * @RPROC_SYNC_STATE_INIT state to use when the remoteproc core >>> + * is initialising. >>> * @RPROC_SYNC_STATE_SHUTDOWN state to use after the remoteproc core >>> * has shutdown (rproc_shutdown()) the >>> * remote processor. >>> @@ -39,6 +41,7 @@ struct rproc_debug_trace { >>> * operation to use. >>> */ >>> enum rproc_sync_states { >>> + RPROC_SYNC_STATE_INIT, >>> RPROC_SYNC_STATE_SHUTDOWN, >>> RPROC_SYNC_STATE_CRASHED, >>> }; >>> @@ -47,6 +50,9 @@ static inline void rproc_set_sync_flag(struct rproc *rproc, >>> enum rproc_sync_states state) >>> { >>> switch (state) { >>> + case RPROC_SYNC_STATE_INIT: >>> + rproc->sync_with_rproc = rproc->sync_flags.on_init; >>> + break; >>> case RPROC_SYNC_STATE_SHUTDOWN: >>> rproc->sync_with_rproc = rproc->sync_flags.after_stop; >>> break; >>> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h >>> index ceb3b2bba824..a75ed92b3de6 100644 >>> --- a/include/linux/remoteproc.h >>> +++ b/include/linux/remoteproc.h >>> @@ -619,6 +619,9 @@ struct rproc *rproc_get_by_child(struct device *dev); >>> struct rproc *rproc_alloc(struct device *dev, const char *name, >>> const struct rproc_ops *ops, >>> const char *firmware, int len); >>> +int rproc_set_state_machine(struct rproc *rproc, >>> + const struct rproc_ops *sync_ops, >>> + struct rproc_sync_flags sync_flags); >>> void rproc_put(struct rproc *rproc); >>> int rproc_add(struct rproc *rproc); >>> int rproc_del(struct rproc *rproc); >>>