greybus: svc watchdog: allow it to be enabled/disabled from userspace

Sometimes you want to disable the SVC watchdog without having to patch
your kernel, so provide a sysfs file to do this.  This can let us do
power measurements, and let the firmware developers not go crazy
worrying that the kernel is going to reset their chips with no notice.

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Greg Kroah-Hartman 2016-01-26 15:17:08 -08:00
parent 7030f9246b
commit d562853d3e
4 changed files with 94 additions and 9 deletions

View File

@ -163,3 +163,11 @@ KernelVersion: 4.XX
Contact: Greg Kroah-Hartman <greg@kroah.com>
Description:
The version number of the firmware in the SVC device.
What: /sys/bus/greybus/device/N-svc/watchdog
Date: October 2016
KernelVersion: 4.XX
Contact: Greg Kroah-Hartman <greg@kroah.com>
Description:
If the SVC watchdog is enabled or not. Writing 0 to this
file will disable the watchdog, writing 1 will enable it.

View File

@ -70,10 +70,42 @@ static ssize_t intf_eject_store(struct device *dev,
}
static DEVICE_ATTR_WO(intf_eject);
static ssize_t watchdog_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct gb_svc *svc = to_gb_svc(dev);
return sprintf(buf, "%s\n",
gb_svc_watchdog_enabled(svc) ? "enabled" : "disabled");
}
static ssize_t watchdog_store(struct device *dev,
struct device_attribute *attr, const char *buf,
size_t len)
{
struct gb_svc *svc = to_gb_svc(dev);
int retval;
bool user_request;
retval = strtobool(buf, &user_request);
if (retval)
return retval;
if (user_request)
retval = gb_svc_watchdog_enable(svc);
else
retval = gb_svc_watchdog_disable(svc);
if (retval)
return retval;
return len;
}
static DEVICE_ATTR_RW(watchdog);
static struct attribute *svc_attrs[] = {
&dev_attr_endo_id.attr,
&dev_attr_ap_intf_id.attr,
&dev_attr_intf_eject.attr,
&dev_attr_watchdog.attr,
NULL,
};
ATTRIBUTE_GROUPS(svc);

View File

@ -61,6 +61,9 @@ int gb_svc_intf_set_power_mode(struct gb_svc *svc, u8 intf_id, u8 hs_series,
int gb_svc_ping(struct gb_svc *svc);
int gb_svc_watchdog_create(struct gb_svc *svc);
void gb_svc_watchdog_destroy(struct gb_svc *svc);
bool gb_svc_watchdog_enabled(struct gb_svc *svc);
int gb_svc_watchdog_enable(struct gb_svc *svc);
int gb_svc_watchdog_disable(struct gb_svc *svc);
int gb_svc_protocol_init(void);
void gb_svc_protocol_exit(void);

View File

@ -15,7 +15,7 @@
struct gb_svc_watchdog {
struct delayed_work work;
struct gb_svc *svc;
bool finished;
bool enabled;
};
static struct delayed_work reset_work;
@ -65,11 +65,16 @@ static void do_work(struct work_struct *work)
INIT_DELAYED_WORK(&reset_work, greybus_reset);
queue_delayed_work(system_wq, &reset_work, HZ/2);
return;
/*
* Disable ourselves, we don't want to trip again unless
* userspace wants us to.
*/
watchdog->enabled = false;
}
/* resubmit our work to happen again, if we are still "alive" */
if (!watchdog->finished)
if (watchdog->enabled)
queue_delayed_work(system_wq, &watchdog->work,
SVC_WATCHDOG_PERIOD);
}
@ -85,14 +90,12 @@ int gb_svc_watchdog_create(struct gb_svc *svc)
if (!watchdog)
return -ENOMEM;
watchdog->finished = false;
watchdog->enabled = false;
watchdog->svc = svc;
INIT_DELAYED_WORK(&watchdog->work, do_work);
svc->watchdog = watchdog;
queue_delayed_work(system_wq, &watchdog->work,
SVC_WATCHDOG_PERIOD);
return 0;
return gb_svc_watchdog_enable(svc);
}
void gb_svc_watchdog_destroy(struct gb_svc *svc)
@ -102,8 +105,47 @@ void gb_svc_watchdog_destroy(struct gb_svc *svc)
if (!watchdog)
return;
watchdog->finished = true;
cancel_delayed_work_sync(&watchdog->work);
gb_svc_watchdog_disable(svc);
svc->watchdog = NULL;
kfree(watchdog);
}
bool gb_svc_watchdog_enabled(struct gb_svc *svc)
{
if (!svc || !svc->watchdog)
return false;
return svc->watchdog->enabled;
}
int gb_svc_watchdog_enable(struct gb_svc *svc)
{
struct gb_svc_watchdog *watchdog;
if (!svc->watchdog)
return -ENODEV;
watchdog = svc->watchdog;
if (watchdog->enabled)
return 0;
watchdog->enabled = true;
queue_delayed_work(system_wq, &watchdog->work,
SVC_WATCHDOG_PERIOD);
return 0;
}
int gb_svc_watchdog_disable(struct gb_svc *svc)
{
struct gb_svc_watchdog *watchdog;
if (!svc->watchdog)
return -ENODEV;
watchdog = svc->watchdog;
if (!watchdog->enabled)
return 0;
watchdog->enabled = false;
cancel_delayed_work_sync(&watchdog->work);
return 0;
}