static struct workqueue_struct *deferred_wq;
static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
+/*
+ * In some cases, like suspend to RAM or hibernation, It might be reasonable
+ * to prohibit probing of devices as it could be unsafe.
+ * Once defer_all_probes is true all drivers probes will be forcibly deferred.
+ */
+static bool defer_all_probes;
+
/*
* deferred_probe_work_func() - Retry probing devices in the active list.
*/
queue_work(deferred_wq, &deferred_probe_work);
}
+/**
+ * device_block_probing() - Block/defere device's probes
+ *
+ * It will disable probing of devices and defer their probes instead.
+ */
+void device_block_probing(void)
+{
+ defer_all_probes = true;
+ /* sync with probes to avoid races. */
+ wait_for_device_probe();
+}
+
+/**
+ * device_unblock_probing() - Unblock/enable device's probes
+ *
+ * It will restore normal behavior and trigger re-probing of deferred
+ * devices.
+ */
+void device_unblock_probing(void)
+{
+ defer_all_probes = false;
+ driver_deferred_probe_trigger();
+}
+
/**
* deferred_probe_initcall() - Enable probing of deferred devices
*
ret = driver_sysfs_add(dev);
if (!ret)
driver_bound(dev);
+ else if (dev->bus)
+ blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
+ BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
return ret;
}
EXPORT_SYMBOL_GPL(device_bind_driver);
static int really_probe(struct device *dev, struct device_driver *drv)
{
- int ret = 0;
+ int ret = -EPROBE_DEFER;
int local_trigger_count = atomic_read(&deferred_trigger_count);
+ if (defer_all_probes) {
+ /*
+ * Value of defer_all_probes can be set only by
+ * device_defer_all_probes_enable() which, in turn, will call
+ * wait_for_device_probe() right after that to avoid any races.
+ */
+ dev_dbg(dev, "Driver %s force probe deferral\n", drv->name);
+ driver_deferred_probe_add(dev);
+ return ret;
+ }
+
atomic_inc(&probe_count);
pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
drv->bus->name, __func__, drv->name, dev_name(dev));
/* If using pinctrl, bind pins now before probing */
ret = pinctrl_bind_pins(dev);
if (ret)
- goto probe_failed;
+ goto pinctrl_bind_failed;
if (driver_sysfs_add(dev)) {
printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
goto done;
probe_failed:
+ if (dev->bus)
+ blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
+ BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
+pinctrl_bind_failed:
devres_release_all(dev);
driver_sysfs_remove(dev);
dev->driver = NULL;
dev_set_drvdata(dev, NULL);
if (dev->pm_domain && dev->pm_domain->dismiss)
dev->pm_domain->dismiss(dev);
+ pm_runtime_reinit(dev);
switch (ret) {
case -EPROBE_DEFER:
*/
void wait_for_device_probe(void)
{
+ /* wait for the deferred probe workqueue to finish */
+ if (driver_deferred_probe_enable)
+ flush_workqueue(deferred_wq);
+
/* wait for the known devices to complete their probing */
wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
async_synchronize_full();
dev_set_drvdata(dev, NULL);
if (dev->pm_domain && dev->pm_domain->dismiss)
dev->pm_domain->dismiss(dev);
+ pm_runtime_reinit(dev);
klist_remove(&dev->p->knode_driver);
if (dev->bus)
blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
BUS_NOTIFY_UNBOUND_DRIVER,
dev);
-
}
}