linux设备驱动(15)type详解

在linux设备驱动中总是见到type的结构体变量，一般是嵌入其他数据结构体中。本节将一 一介绍下。

bus_type是bus总结对应的结构体变量，不属于本节所叙述范围。

1 device_type

定义位于：include\linux\device.h，devices_type嵌入结构体device中

 1 /*
 2  * The type of device, "struct device" is embedded in. A class
 3  * or bus can contain devices of different types
 4  * like "partitions" and "disks", "mouse" and "event".
 5  * This identifies the device type and carries type-specific
 6  * information, equivalent to the kobj_type of a kobject.
 7  * If "name" is specified, the uevent will contain it in
 8  * the DEVTYPE variable.
 9  */
10 struct device_type {
11     const char *name;
12     const struct attribute_group **groups;
13     int (*uevent)(struct device *dev, struct kobj_uevent_env *env);
14     char *(*devnode)(struct device *dev, umode_t *mode,
15              kuid_t *uid, kgid_t *gid);
16     void (*release)(struct device *dev);
17 
18     const struct dev_pm_ops *pm;
19 };
device_add_attrs()中device_add_groups将device_type加入group中
 1 static int device_add_attrs(struct device *dev)
 2 {
 3     struct class *class = dev->class;
 4     const struct device_type *type = dev->type;
 5     int error;
 6 
 7     if (class) {
 8         error = device_add_attributes(dev, class->dev_attrs);
 9         if (error)
10             return error;
11         error = device_add_bin_attributes(dev, class->dev_bin_attrs);
12         if (error)
13             goto err_remove_class_attrs;
14     }
15 
16     if (type) {
17         error = device_add_groups(dev, type->groups);
18         if (error)
19             goto err_remove_class_bin_attrs;
20     }
21 
22     error = device_add_groups(dev, dev->groups);
23     if (error)
24         goto err_remove_type_groups;
25 
26     return 0;
27 
28  err_remove_type_groups:
29     if (type)
30         device_remove_groups(dev, type->groups);
31  err_remove_class_bin_attrs:
32     if (class)
33         device_remove_bin_attributes(dev, class->dev_bin_attrs);
34  err_remove_class_attrs:
35     if (class)
36         device_remove_attributes(dev, class->dev_attrs);
37 
38     return error;
39 }

2.kobject_type 

定义位于：include\linux\kobject.h，kobject_type嵌入结构体kobject中

1 struct kobj_type {
2     void (*release)(struct kobject *kobj);
3     const struct sysfs_ops *sysfs_ops;
4     struct attribute **default_attrs;
5     const struct kobj_ns_type_operations *(*child_ns_type)(struct kobject *kobj);
6     const void *(*namespace)(struct kobject *kobj);
7 };

kobject_init()会初始化kobject中的kobj_type

 1 void kobject_init(struct kobject *kobj, struct kobj_type *ktype)
 2 {
 3     char *err_str;
 4 
 5     if (!kobj) {
 6         err_str = "invalid kobject pointer!";
 7         goto error;
 8     }
 9     if (!ktype) {
10         err_str = "must have a ktype to be initialized properly!\n";
11         goto error;
12     }
13     if (kobj->state_initialized) {
14         /* do not error out as sometimes we can recover */
15         printk(KERN_ERR "kobject (%p): tried to init an initialized "
16                "object, something is seriously wrong.\n", kobj);
17         dump_stack();
18     }
19 
20     kobject_init_internal(kobj);
21     kobj->ktype = ktype;
22     return;
23 
24 error:
25     printk(KERN_ERR "kobject (%p): %s\n", kobj, err_str);
26     dump_stack();
27 }

3. kset_type

实际上同kobj_type

定义如下：

1 static struct kobj_type kset_ktype = {
2     .sysfs_ops    = &kobj_sysfs_ops,
3     .release = kset_release,
4 };

 

kset_create时会用kset_type初始化kset中kobj的kobj_type
 1 static struct kset *kset_create(const char *name,
 2                 const struct kset_uevent_ops *uevent_ops,
 3                 struct kobject *parent_kobj)
 4 {
 5     struct kset *kset;
 6     int retval;
 7 
 8     kset = kzalloc(sizeof(*kset), GFP_KERNEL);
 9     if (!kset)
10         return NULL;
11     retval = kobject_set_name(&kset->kobj, name);
12     if (retval) {
13         kfree(kset);
14         return NULL;
15     }
16     kset->uevent_ops = uevent_ops;
17     kset->kobj.parent = parent_kobj;
18 
19     /*
20      * The kobject of this kset will have a type of kset_ktype and belong to
21      * no kset itself.  That way we can properly free it when it is
22      * finished being used.
23      */
24     kset->kobj.ktype = &kset_ktype;
25     kset->kobj.kset = NULL;
26 
27     return kset;
28 }

 

其他待续。。。

 

posted @ 2020-05-23 18:20  Action_er  阅读(954)  评论(0)  编辑  收藏  举报