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Message-ID: <250d6776-5aca-67e9-ac4c-73d8d43b0592@quicinc.com>
Date: Tue, 11 Jul 2023 13:30:24 +0530
From: Vignesh Viswanathan <quic_viswanat@...cinc.com>
To: Mukesh Ojha <quic_mojha@...cinc.com>, <agross@...nel.org>,
<andersson@...nel.org>, <konrad.dybcio@...aro.org>,
<mathieu.poirier@...aro.org>, <linux-arm-msm@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <linux-remoteproc@...r.kernel.org>
CC: <quic_srichara@...cinc.com>, <quic_varada@...cinc.com>,
<quic_kathirav@...cinc.com>, <quic_devipriy@...cinc.com>,
<quic_sjaganat@...cinc.com>
Subject: Re: [PATCH] remoteproc: qcom: Add NOTIFY_FATAL event type to SSR
subdevice
On 6/15/2023 4:10 PM, Vignesh Viswanathan wrote:
>
>
> On 5/29/2023 9:27 AM, Vignesh Viswanathan wrote:
>> Gentle Reminder.
>>
>> On 5/22/2023 3:03 PM, Mukesh Ojha wrote:
>>>
>>>
>>> On 5/3/2023 4:56 PM, Mukesh Ojha wrote:
>>>>
>>>>
>>>> On 5/3/2023 11:51 AM, Vignesh Viswanathan wrote:
>>>>> Currently the SSR subdevice notifies the client driver on crash of the
>>>>> rproc from the recovery workqueue using the BEFORE_SHUTDOWN event.
>>>>> However the client driver might be interested to know that the device
>>>>> has crashed immediately to pause any further transactions with the
>>>>> rproc. This calls for an event to be sent to the driver in the IRQ
>>>>> context as soon as the rproc crashes.
>>>>>
>>>>> Add NOTIFY_FATAL event to SSR subdevice to atomically notify rproc has
>>>>> crashed to the client driver.
>>>>>
>>>>> Validated the event in IPQ9574 and IPQ5332 by forcing the rproc to
>>>>> crash
>>>>> and ensuring the registered notifier function receives the
>>>>> notification
>>>>> in IRQ context.
>>>>
>>>> This was one of valid use case we encounter in android, We have some
>>>> other way of doing the same thing without core kernel change with
>>>> something called early notifiers.
>>>>
>>>> https://git.codelinaro.org/clo/la/kernel/msm-5.15/-/commit/7583d24de337aa1bf7c375a7da706af9b995b9a1#a840754ebb0e24e88adbf48177e1abd0830b72d2
>>>>
>>>> https://git.codelinaro.org/clo/la/kernel/msm-5.15/-/commit/257de41c63a5a51a081cc7887cdaa4a46e4d1744
>>>>
>>>> But good to address this if possible.
>>>
>>> Ack the idea of early notifier;
>>> But here, atomic does not guarantees it to be atomic.
>>>
>>> Acked-by: Mukesh Ojha <quic_mojha@...cinc.com>
>>>
>>> -- Mukesh
>>>
> Gentle Reminder!
>
> Thanks,
> Vignesh
>
Gentle reminder for review!
Thanks,
Vignesh
>>>
>>>>
>>>> -Mukesh
>>>>>
>>>>> Signed-off-by: Vignesh Viswanathan <quic_viswanat@...cinc.com>
>>>>> ---
>>>>> drivers/remoteproc/qcom_common.c | 60
>>>>> +++++++++++++++++++++++++++
>>>>> drivers/remoteproc/remoteproc_core.c | 12 ++++++
>>>>> include/linux/remoteproc.h | 3 ++
>>>>> include/linux/remoteproc/qcom_rproc.h | 17 ++++++++
>>>>> 4 files changed, 92 insertions(+)
>>>>>
>>>>> diff --git a/drivers/remoteproc/qcom_common.c
>>>>> b/drivers/remoteproc/qcom_common.c
>>>>> index a0d4238492e9..76542229aeb6 100644
>>>>> --- a/drivers/remoteproc/qcom_common.c
>>>>> +++ b/drivers/remoteproc/qcom_common.c
>>>>> @@ -84,6 +84,7 @@ struct minidump_global_toc {
>>>>> struct qcom_ssr_subsystem {
>>>>> const char *name;
>>>>> struct srcu_notifier_head notifier_list;
>>>>> + struct atomic_notifier_head atomic_notifier_list;
>>>>> struct list_head list;
>>>>> };
>>>>> @@ -366,6 +367,7 @@ static struct qcom_ssr_subsystem
>>>>> *qcom_ssr_get_subsys(const char *name)
>>>>> }
>>>>> info->name = kstrdup_const(name, GFP_KERNEL);
>>>>> srcu_init_notifier_head(&info->notifier_list);
>>>>> + ATOMIC_INIT_NOTIFIER_HEAD(&info->atomic_notifier_list);
>>>>> /* Add to global notification list */
>>>>> list_add_tail(&info->list, &qcom_ssr_subsystem_list);
>>>>> @@ -417,6 +419,51 @@ int qcom_unregister_ssr_notifier(void *notify,
>>>>> struct notifier_block *nb)
>>>>> }
>>>>> EXPORT_SYMBOL_GPL(qcom_unregister_ssr_notifier);
>>>>> +/**
>>>>> + * qcom_register_ssr_atomic_notifier() - register SSR Atomic
>>>>> notification
>>>>> + * handler
>>>>> + * @name: Subsystem's SSR name
>>>>> + * @nb: notifier_block to be invoked upon subsystem's state change
>>>>> + *
>>>>> + * This registers the @nb notifier block as part the atomic notifier
>>>>> + * chain for a remoteproc associated with @name. The notifier
>>>>> block's callback
>>>>> + * will be invoked when the remote processor crashes in atomic
>>>>> context before
>>>>> + * the recovery process is queued.
>>>>> + *
>>>>> + * Return: a subsystem cookie on success, ERR_PTR on failure.
>>>>> + */
>>>>> +void *qcom_register_ssr_atomic_notifier(const char *name,
>>>>> + struct notifier_block *nb)
>>>>> +{
>>>>> + struct qcom_ssr_subsystem *info;
>>>>> +
>>>>> + info = qcom_ssr_get_subsys(name);
>>>>> + if (IS_ERR(info))
>>>>> + return info;
>>>>> +
>>>>> + atomic_notifier_chain_register(&info->atomic_notifier_list, nb);
>>>>> +
>>>>> + return &info->atomic_notifier_list;
>>>>> +}
>>>>> +EXPORT_SYMBOL_GPL(qcom_register_ssr_atomic_notifier);
>>>>> +
>>>>> +/**
>>>>> + * qcom_unregister_ssr_atomic_notifier() - unregister SSR Atomic
>>>>> notification
>>>>> + * handler
>>>>> + * @notify: subsystem cookie returned from
>>>>> qcom_register_ssr_notifier
>>>>> + * @nb: notifier_block to unregister
>>>>> + *
>>>>> + * This function will unregister the notifier from the atomic
>>>>> notifier
>>>>> + * chain.
>>>>> + *
>>>>> + * Return: 0 on success, %ENOENT otherwise.
>>>>> + */
>>>>> +int qcom_unregister_ssr_atomic_notifier(void *notify, struct
>>>>> notifier_block *nb)
>>>>> +{
>>>>> + return atomic_notifier_chain_unregister(notify, nb);
>>>>> +}
>>>>> +EXPORT_SYMBOL_GPL(qcom_unregister_ssr_atomic_notifier);
>>>>> +
>>>>> static int ssr_notify_prepare(struct rproc_subdev *subdev)
>>>>> {
>>>>> struct qcom_rproc_ssr *ssr = to_ssr_subdev(subdev);
>>>>> @@ -467,6 +514,18 @@ static void ssr_notify_unprepare(struct
>>>>> rproc_subdev *subdev)
>>>>> QCOM_SSR_AFTER_SHUTDOWN, &data);
>>>>> }
>>>>> +static void ssr_notify_crash(struct rproc_subdev *subdev)
>>>>> +{
>>>>> + struct qcom_rproc_ssr *ssr = to_ssr_subdev(subdev);
>>>>> + struct qcom_ssr_notify_data data = {
>>>>> + .name = ssr->info->name,
>>>>> + .crashed = true,
>>>>> + };
>>>>> +
>>>>> + atomic_notifier_call_chain(&ssr->info->atomic_notifier_list,
>>>>> + QCOM_SSR_NOTIFY_CRASH, &data);
>>>>> +}
>>>>> +
>>>>> /**
>>>>> * qcom_add_ssr_subdev() - register subdevice as restart
>>>>> notification source
>>>>> * @rproc: rproc handle
>>>>> @@ -493,6 +552,7 @@ void qcom_add_ssr_subdev(struct rproc *rproc,
>>>>> struct qcom_rproc_ssr *ssr,
>>>>> ssr->subdev.start = ssr_notify_start;
>>>>> ssr->subdev.stop = ssr_notify_stop;
>>>>> ssr->subdev.unprepare = ssr_notify_unprepare;
>>>>> + ssr->subdev.notify_crash = ssr_notify_crash;
>>>>> rproc_add_subdev(rproc, &ssr->subdev);
>>>>> }
>>>>> diff --git a/drivers/remoteproc/remoteproc_core.c
>>>>> b/drivers/remoteproc/remoteproc_core.c
>>>>> index 695cce218e8c..3de0ece158ea 100644
>>>>> --- a/drivers/remoteproc/remoteproc_core.c
>>>>> +++ b/drivers/remoteproc/remoteproc_core.c
>>>>> @@ -1139,6 +1139,16 @@ static void
>>>>> rproc_unprepare_subdevices(struct rproc *rproc)
>>>>> }
>>>>> }
>>>>> +static void rproc_notify_crash_subdevices(struct rproc *rproc)
>>>>> +{
>>>>> + struct rproc_subdev *subdev;
>>>>> +
>>>>> + list_for_each_entry_reverse(subdev, &rproc->subdevs, node) {
>>>>> + if (subdev->notify_crash)
>>>>> + subdev->notify_crash(subdev);
>>>>> + }
>>>>> +}
>>>>> +
>>>>> /**
>>>>> * rproc_alloc_registered_carveouts() - allocate all carveouts
>>>>> registered
>>>>> * in the list
>>>>> @@ -2687,6 +2697,8 @@ void rproc_report_crash(struct rproc *rproc,
>>>>> enum rproc_crash_type type)
>>>>> dev_err(&rproc->dev, "crash detected in %s: type %s\n",
>>>>> rproc->name, rproc_crash_to_string(type));
>>>>> + rproc_notify_crash_subdevices(rproc);
>>>>> +
>>>>> queue_work(rproc_recovery_wq, &rproc->crash_handler);
>>>>> }
>>>>> EXPORT_SYMBOL(rproc_report_crash);
>>>>> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
>>>>> index fe8978eb69f1..f3c0e0103e81 100644
>>>>> --- a/include/linux/remoteproc.h
>>>>> +++ b/include/linux/remoteproc.h
>>>>> @@ -596,6 +596,8 @@ struct rproc {
>>>>> * @stop: stop function, called before the rproc is stopped; the
>>>>> @crashed
>>>>> * parameter indicates if this originates from a recovery
>>>>> * @unprepare: unprepare function, called after the rprochas
>>>>> been stopped
>>>>> + * @notify_crash: notify_crash function, called in atomic context
>>>>> to notify
>>>>> + * rproc has crashed and recovery is about to start
>>>>> */
>>>>> struct rproc_subdev {
>>>>> struct list_head node;
>>>>> @@ -604,6 +606,7 @@ struct rproc_subdev {
>>>>> int (*start)(struct rproc_subdev *subdev);
>>>>> void (*stop)(struct rproc_subdev *subdev, bool crashed);
>>>>> void (*unprepare)(struct rproc_subdev *subdev);
>>>>> + void (*notify_crash)(struct rproc_subdev *subdev);
>>>>> };
>>>>> /* we currently support only two vrings per rvdev */
>>>>> diff --git a/include/linux/remoteproc/qcom_rproc.h
>>>>> b/include/linux/remoteproc/qcom_rproc.h
>>>>> index 82b211518136..f3d06900f297 100644
>>>>> --- a/include/linux/remoteproc/qcom_rproc.h
>>>>> +++ b/include/linux/remoteproc/qcom_rproc.h
>>>>> @@ -11,12 +11,14 @@ struct notifier_block;
>>>>> * @QCOM_SSR_AFTER_POWERUP: Remoteproc is running (start stage)
>>>>> * @QCOM_SSR_BEFORE_SHUTDOWN: Remoteproc crashed or shutting
>>>>> down (stop stage)
>>>>> * @QCOM_SSR_AFTER_SHUTDOWN: Remoteprocis down (unprepare stage)
>>>>> + * @QCOM_SSR_NOTIFY_CRASH: Remoteproc crashed
>>>>> */
>>>>> enum qcom_ssr_notify_type {
>>>>> QCOM_SSR_BEFORE_POWERUP,
>>>>> QCOM_SSR_AFTER_POWERUP,
>>>>> QCOM_SSR_BEFORE_SHUTDOWN,
>>>>> QCOM_SSR_AFTER_SHUTDOWN,
>>>>> + QCOM_SSR_NOTIFY_CRASH,
>>>>> };
>>>>> struct qcom_ssr_notify_data {
>>>>> @@ -29,6 +31,10 @@ struct qcom_ssr_notify_data {
>>>>> void *qcom_register_ssr_notifier(const char *name, struct
>>>>> notifier_block *nb);
>>>>> int qcom_unregister_ssr_notifier(void *notify, struct
>>>>> notifier_block *nb);
>>>>> +void *qcom_register_ssr_atomic_notifier(const char *name,
>>>>> + struct notifier_block *nb);
>>>>> +int qcom_unregister_ssr_atomic_notifier(void *notify,
>>>>> + struct notifier_block *nb);
>>>>> #else
>>>>> static inline void *qcom_register_ssr_notifier(const char *name,
>>>>> @@ -43,6 +49,17 @@ static inline int
>>>>> qcom_unregister_ssr_notifier(void *notify,
>>>>> return 0;
>>>>> }
>>>>> +static inline void *qcom_register_ssr_atomic_notifier(const char
>>>>> *name,
>>>>> + struct notifier_block *nb)
>>>>> +{
>>>>> + return 0;
>>>>> +}
>>>>> +
>>>>> +static inline int qcom_unregister_ssr_atomic_notifier(void *notify,
>>>>> + struct notifier_block *nb)
>>>>> +{
>>>>> + return 0;
>>>>> +}
>>>>> #endif
>>>>> #endif
>>>>
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