Clients can register their callbacks for power-on/off notifications of remote processors. While executing the notifier chain sometimes these callbacks may get stuck or take a long time which is not desired. To detect such cases this patch introduces a timeout and prints out a warning indicating that notifier chain is taking a long time. The timeout is set to 20secs by default and can be adjusted.
Signed-off-by: Rishabh Bhatnagar <[email protected]> --- drivers/remoteproc/Kconfig | 16 ++++++++++++++++ drivers/remoteproc/qcom_common.c | 41 ++++++++++++++++++++++++++++++++-------- 2 files changed, 49 insertions(+), 8 deletions(-) diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig index d99548f..e1e623e 100644 --- a/drivers/remoteproc/Kconfig +++ b/drivers/remoteproc/Kconfig @@ -234,6 +234,22 @@ config QCOM_WCNSS_PIL Say y here to support the Peripheral Image Loader for the Qualcomm Wireless Connectivity Subsystem. +config QCOM_NOTIFY_TIMEOUT + int "Default timeout for ssr notifications to complete (in milliseconds)" + depends on QCOM_RPROC_COMMON + default 20000 + help + As part of ssr notification clients can register their callbacks + to a notifier chain which is invoked whenever the remoteproc + powers-on/off. This option controls the timeout for ssr notifications + to complete. + This is a good to have debug feature as sometimes callbacks + can get stuck or take a long time. This feature helps in identifying + such scenarios. + + The default value is kept as 20 secs and should be left as it is + in most cases. + config ST_REMOTEPROC tristate "ST remoteproc support" depends on ARCH_STI diff --git a/drivers/remoteproc/qcom_common.c b/drivers/remoteproc/qcom_common.c index 085fd73..d72c4f5 100644 --- a/drivers/remoteproc/qcom_common.c +++ b/drivers/remoteproc/qcom_common.c @@ -29,6 +29,8 @@ struct qcom_ssr_subsystem { const char *name; struct srcu_notifier_head notifier_list; struct list_head list; + struct timer_list notify_timer; + const char *notify_type; }; static LIST_HEAD(qcom_ssr_subsystem_list); @@ -198,6 +200,14 @@ void qcom_remove_smd_subdev(struct rproc *rproc, struct qcom_rproc_subdev *smd) } EXPORT_SYMBOL_GPL(qcom_remove_smd_subdev); +static void notify_timeout_handler(struct timer_list *t) +{ + struct qcom_ssr_subsystem *info = from_timer(info, t, notify_timer); + + WARN(1, "srcu notifier chain for %s:%s taking too long", info->name, + info->notify_type); +} + static struct qcom_ssr_subsystem *qcom_ssr_get_subsys(const char *name) { struct qcom_ssr_subsystem *info; @@ -216,6 +226,9 @@ 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); + /* Setup the notification timer */ + timer_setup(&info->notify_timer, notify_timeout_handler, 0); + /* Add to global notification list */ list_add_tail(&info->list, &qcom_ssr_subsystem_list); @@ -266,6 +279,18 @@ int qcom_unregister_ssr_notifier(void *notify, struct notifier_block *nb) } EXPORT_SYMBOL_GPL(qcom_unregister_ssr_notifier); +static inline void notify_ssr_clients(struct qcom_rproc_ssr *ssr, + enum qcom_ssr_notify_type type, + struct qcom_ssr_notify_data *data) +{ + unsigned long timeout; + + timeout = jiffies + msecs_to_jiffies(CONFIG_QCOM_NOTIFY_TIMEOUT); + mod_timer(&ssr->info->notify_timer, timeout); + srcu_notifier_call_chain(&ssr->info->notifier_list, type, data); + del_timer_sync(&ssr->info->notify_timer); +} + static int ssr_notify_prepare(struct rproc_subdev *subdev) { struct qcom_rproc_ssr *ssr = to_ssr_subdev(subdev); @@ -274,8 +299,8 @@ static int ssr_notify_prepare(struct rproc_subdev *subdev) .crashed = false, }; - srcu_notifier_call_chain(&ssr->info->notifier_list, - QCOM_SSR_BEFORE_POWERUP, &data); + ssr->info->notify_type = "BEFORE_POWERUP"; + notify_ssr_clients(ssr, QCOM_SSR_BEFORE_POWERUP, &data); return 0; } @@ -287,8 +312,8 @@ static int ssr_notify_start(struct rproc_subdev *subdev) .crashed = false, }; - srcu_notifier_call_chain(&ssr->info->notifier_list, - QCOM_SSR_AFTER_POWERUP, &data); + ssr->info->notify_type = "AFTER_POWERUP"; + notify_ssr_clients(ssr, QCOM_SSR_AFTER_POWERUP, &data); return 0; } @@ -300,8 +325,8 @@ static void ssr_notify_stop(struct rproc_subdev *subdev, bool crashed) .crashed = crashed, }; - srcu_notifier_call_chain(&ssr->info->notifier_list, - QCOM_SSR_BEFORE_SHUTDOWN, &data); + ssr->info->notify_type = "BEFORE_SHUTDOWN"; + notify_ssr_clients(ssr, QCOM_SSR_BEFORE_SHUTDOWN, &data); } static void ssr_notify_unprepare(struct rproc_subdev *subdev) @@ -312,8 +337,8 @@ static void ssr_notify_unprepare(struct rproc_subdev *subdev) .crashed = false, }; - srcu_notifier_call_chain(&ssr->info->notifier_list, - QCOM_SSR_AFTER_SHUTDOWN, &data); + ssr->info->notify_type = "AFTER_SHUTDOWN"; + notify_ssr_clients(ssr, QCOM_SSR_AFTER_SHUTDOWN, &data); } /** -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
