diff options
Diffstat (limited to 'drivers/base/core.c')
| -rw-r--r-- | drivers/base/core.c | 99 |
1 files changed, 93 insertions, 6 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c index 2fde698430df..cbc0099d8ef2 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -2624,6 +2624,35 @@ static const char *dev_uevent_name(const struct kobject *kobj) return NULL; } +/* + * Try filling "DRIVER=<name>" uevent variable for a device. Because this + * function may race with binding and unbinding the device from a driver, + * we need to be careful. Binding is generally safe, at worst we miss the + * fact that the device is already bound to a driver (but the driver + * information that is delivered through uevents is best-effort, it may + * become obsolete as soon as it is generated anyways). Unbinding is more + * risky as driver pointer is transitioning to NULL, so READ_ONCE() should + * be used to make sure we are dealing with the same pointer, and to + * ensure that driver structure is not going to disappear from under us + * we take bus' drivers klist lock. The assumption that only registered + * driver can be bound to a device, and to unregister a driver bus code + * will take the same lock. + */ +static void dev_driver_uevent(const struct device *dev, struct kobj_uevent_env *env) +{ + struct subsys_private *sp = bus_to_subsys(dev->bus); + + if (sp) { + scoped_guard(spinlock, &sp->klist_drivers.k_lock) { + struct device_driver *drv = READ_ONCE(dev->driver); + if (drv) + add_uevent_var(env, "DRIVER=%s", drv->name); + } + + subsys_put(sp); + } +} + static int dev_uevent(const struct kobject *kobj, struct kobj_uevent_env *env) { const struct device *dev = kobj_to_dev(kobj); @@ -2655,8 +2684,8 @@ static int dev_uevent(const struct kobject *kobj, struct kobj_uevent_env *env) if (dev->type && dev->type->name) add_uevent_var(env, "DEVTYPE=%s", dev->type->name); - if (dev->driver) - add_uevent_var(env, "DRIVER=%s", dev->driver->name); + /* Add "DRIVER=%s" variable if the device is bound to a driver */ + dev_driver_uevent(dev, env); /* Add common DT information about the device */ of_device_uevent(dev, env); @@ -2726,11 +2755,8 @@ static ssize_t uevent_show(struct device *dev, struct device_attribute *attr, if (!env) return -ENOMEM; - /* Synchronize with really_probe() */ - device_lock(dev); /* let the kset specific function add its keys */ retval = kset->uevent_ops->uevent(&dev->kobj, env); - device_unlock(dev); if (retval) goto out; @@ -3700,7 +3726,7 @@ done: device_pm_remove(dev); dpm_sysfs_remove(dev); DPMError: - dev->driver = NULL; + device_set_driver(dev, NULL); bus_remove_device(dev); BusError: device_remove_attrs(dev); @@ -5172,6 +5198,67 @@ void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode) EXPORT_SYMBOL_GPL(set_secondary_fwnode); /** + * device_remove_of_node - Remove an of_node from a device + * @dev: device whose device tree node is being removed + */ +void device_remove_of_node(struct device *dev) +{ + dev = get_device(dev); + if (!dev) + return; + + if (!dev->of_node) + goto end; + + if (dev->fwnode == of_fwnode_handle(dev->of_node)) + dev->fwnode = NULL; + + of_node_put(dev->of_node); + dev->of_node = NULL; + +end: + put_device(dev); +} +EXPORT_SYMBOL_GPL(device_remove_of_node); + +/** + * device_add_of_node - Add an of_node to an existing device + * @dev: device whose device tree node is being added + * @of_node: of_node to add + * + * Return: 0 on success or error code on failure. + */ +int device_add_of_node(struct device *dev, struct device_node *of_node) +{ + int ret; + + if (!of_node) + return -EINVAL; + + dev = get_device(dev); + if (!dev) + return -EINVAL; + + if (dev->of_node) { + dev_err(dev, "Cannot replace node %pOF with %pOF\n", + dev->of_node, of_node); + ret = -EBUSY; + goto end; + } + + dev->of_node = of_node_get(of_node); + + if (!dev->fwnode) + dev->fwnode = of_fwnode_handle(of_node); + + ret = 0; +end: + put_device(dev); + return ret; +} +EXPORT_SYMBOL_GPL(device_add_of_node); + +/** * device_set_of_node_from_dev - reuse device-tree node of another device * @dev: device whose device-tree node is being set * @dev2: device whose device-tree node is being reused |