From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keerthy Subject: Re: [PATCH] thermal: omap-thermal: Add notify function to thermal_zone_device_ops Date: Mon, 7 Mar 2016 13:03:39 +0530 Message-ID: <56DD2ED3.10609@ti.com> References: <1455599145-5656-1-git-send-email-j-keerthy@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from arroyo.ext.ti.com ([192.94.94.40]:54555 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752025AbcCGHdo (ORCPT ); Mon, 7 Mar 2016 02:33:44 -0500 In-Reply-To: <1455599145-5656-1-git-send-email-j-keerthy@ti.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Keerthy , edubezval@gmail.com Cc: nm@ti.com, rui.zhang@intel.com, linux-pm@vger.kernel.org, linux-omap@vger.kernel.org Eduardo, On Tuesday 16 February 2016 10:35 AM, Keerthy wrote: > notify function is used to notify when some temperature thresholds > are crossed. In case we get notified for a critical trip point then > schedule an emergency shutdown function to backup orderly_poweroff > failures. > > orderly_poweroff is triggered when a graceful shutdown > of system is desired. This may be used in many critical states of the > kernel such as when subsystems detects conditions such as critical > temperature conditions. However, in certain conditions in system > boot up sequences like those in the middle of driver probes being > initiated, userspace will be unable to power off the system in a clean > manner and leaves the system in a critical state. In cases like these, > the /sbin/poweroff will return success (having forked off to attempt > powering off the system. However, the system overall will fail to > completely poweroff (since other modules will be probed) and the system > is still functional with no userspace (since that would have shut itself > off). > > However, there is no clean way of detecting such failure of userspace > powering off the system. In such scenarios, it is necessary for a backup > workqueue to be able to force a shutdown of the system when orderly > shutdown is not successful after a configurable time period. > A gentle ping on this. > Signed-off-by: Keerthy > --- > > The previous discussion: > > https://lkml.org/lkml/2016/1/28/989 > > Making use of the notify ops to schedule a backup thermal shutdown. > > drivers/thermal/ti-soc-thermal/Kconfig | 13 +++++++ > drivers/thermal/ti-soc-thermal/ti-thermal-common.c | 43 ++++++++++++++++++++++ > 2 files changed, 56 insertions(+) > > diff --git a/drivers/thermal/ti-soc-thermal/Kconfig b/drivers/thermal/ti-soc-thermal/Kconfig > index ea8283f..b4b9668 100644 > --- a/drivers/thermal/ti-soc-thermal/Kconfig > +++ b/drivers/thermal/ti-soc-thermal/Kconfig > @@ -71,3 +71,16 @@ config DRA752_THERMAL > > This includes alert interrupts generation and also the TSHUT > support. > + > +config TI_THERMAL_EMERGENCY_POWEROFF_DELAY_MS > + int "Emergency poweroff delay in milli-seconds" > + depends on TI_SOC_THERMAL > + default 0 > + help > + The number of milliseconds to delay before emergency > + poweroff kicks in. The delay should be carefully profiled > + so as to give adequate time for orderly_poweroff. In case > + of failure of an orderly_poweroff the emergency poweroff > + kicks in after the delay has elapsed and shuts down the system. > + > + If set to 0 poweroff will happen immediately. > diff --git a/drivers/thermal/ti-soc-thermal/ti-thermal-common.c b/drivers/thermal/ti-soc-thermal/ti-thermal-common.c > index b213a12..d48eb5b1 100644 > --- a/drivers/thermal/ti-soc-thermal/ti-thermal-common.c > +++ b/drivers/thermal/ti-soc-thermal/ti-thermal-common.c > @@ -31,6 +31,7 @@ > #include > #include > #include > +#include > > #include "ti-thermal.h" > #include "ti-bandgap.h" > @@ -286,6 +287,47 @@ static int ti_thermal_get_crit_temp(struct thermal_zone_device *thermal, > return ti_thermal_get_trip_temp(thermal, OMAP_TRIP_NUMBER - 1, temp); > } > > +/** > + * emergency_poweroff_func - emergency poweroff work after a known delay > + * @work: work_struct associated with the emergency poweroff function > + * > + * This function is called in very critical situations to force > + * a kernel poweroff after a configurable timeout value. > + */ > +static void emergency_poweroff_func(struct work_struct *work) > +{ > + pr_warn("Attempting kernel_power_off\n"); > + kernel_power_off(); > + > + pr_warn("kernel_power_off has failed! Attempting emergency_restart\n"); > + emergency_restart(); > +} > + > +static DECLARE_DELAYED_WORK(emergency_poweroff_work, emergency_poweroff_func); > + > +/** > + * emergency_poweroff - Trigger an emergency system poweroff > + * > + * This may be called from any critical situation to trigger a system shutdown > + * after a known period of time. By default the delay is 0 millisecond > + */ > +void ti_thermal_emergency_poweroff(void) > +{ > + schedule_delayed_work(&emergency_poweroff_work, > + msecs_to_jiffies(CONFIG_TI_THERMAL_EMERGENCY_POWEROFF_DELAY_MS)); > +} > + > +static int ti_thermal_notify(struct thermal_zone_device *thermal, int temp, > + enum thermal_trip_type type) > +{ > + if (type == THERMAL_TRIP_CRITICAL) { > + pr_warn("critical temperature %d reached", temp); > + ti_thermal_emergency_poweroff(); > + } > + > + return 0; > +} > + > static const struct thermal_zone_of_device_ops ti_of_thermal_ops = { > .get_temp = __ti_thermal_get_temp, > .get_trend = __ti_thermal_get_trend, > @@ -301,6 +343,7 @@ static struct thermal_zone_device_ops ti_thermal_ops = { > .get_trip_type = ti_thermal_get_trip_type, > .get_trip_temp = ti_thermal_get_trip_temp, > .get_crit_temp = ti_thermal_get_crit_temp, > + .notify = ti_thermal_notify, > }; > > static struct ti_thermal_data >