Messages in this thread | | | Subject | Re: [PATCH 6/6] remoteproc: qcom: Add notification types to SSR | From | Siddharth Gupta <> | Date | Wed, 1 Apr 2020 18:01:16 -0700 |
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On 3/9/2020 10:34 AM, Mathieu Poirier wrote:
> On Tue, 3 Mar 2020 at 16:30, <rishabhb@codeaurora.org> wrote: >> On 2020-03-03 10:05, Mathieu Poirier wrote: >>> On Mon, 2 Mar 2020 at 13:54, <rishabhb@codeaurora.org> 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 <sidgup@codeaurora.org> >>>>>>>> --- >>>>>>>> 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?
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
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