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Message-ID: <3687b420-0993-7f76-7116-114b1784de05@quicinc.com>
Date: Mon, 29 May 2023 09:27:14 +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
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
>
>
>>
>> -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 rproc has 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: Remoteproc is 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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