linux设备模型之总线，设备，驱动模型

驱动模型：

为了方便维护设备和驱动，内核抽象出三个类：

总线 struct bus_type;

设备 struct device;

驱动 struct device_driver;

这里的总线是抽象的该念总线，逻辑层面的，只是为了管理匹配

向内核注册并和总线关联的设备和驱动的，匹配规则决定于总线。

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struct bus_type {

const char *name; //总线的名字，注册成功后会见于/sys/bus/

const char *dev_name;

struct device *dev_root;

struct bus_attribute *bus_attrs;

struct device_attribute *dev_attrs;

struct driver_attribute *drv_attrs;

int (*match)(struct device *dev, struct device_driver *drv); //匹配规则

int (*uevent)(struct device *dev, struct kobj_uevent_env *env);

int (*probe)(struct device *dev);

int (*remove)(struct device *dev);

void (*shutdown)(struct device *dev);

int (*suspend)(struct device *dev, pm_message_t state);

int (*resume)(struct device *dev);

const struct dev_pm_ops *pm;

struct iommu_ops *iommu_ops;

struct subsys_private *p;

};



int (*match)(struct device *dev, struct device_driver *drv); //匹配规则

匹配规则由编写驱动者自己定义。但是匹配成功必须返回1，否则返回0；

总线的注册：

bus_register(struct bus_type *bus);

bus_unregister(struct bus_type *bus);

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设备：

struct device {

struct device *parent;

struct device_private *p;

struct kobject kobj;

const char *init_name; /* initial name of the device */ //设备的名字

// /sys/bus/xx/devices

const struct device_type *type;

struct mutex mutex; /* mutex to synchronize calls to

* its driver.

*/



//用于关联的总线

struct bus_type *bus; /* type of bus device is on */

//匹配成功后指向设备的驱动结构体变量。

struct device_driver *driver; /* which driver has allocated this

device */

//很重要

void *platform_data; /* Platform specific data, device

core doesn't touch it */

struct dev_pm_info power;

struct dev_pm_domain *pm_domain;

#ifdef CONFIG_NUMA

int numa_node; /* NUMA node this device is close to */

#endif

u64 *dma_mask; /* dma mask (if dma'able device) */

u64 coherent_dma_mask;/* Like dma_mask, but for

alloc_coherent mappings as

not all hardware supports

64 bit addresses for consistent

allocations such descriptors. */

struct device_dma_parameters *dma_parms;

struct list_head dma_pools; /* dma pools (if dma'ble) */

struct dma_coherent_mem *dma_mem; /* internal for coherent mem

override */

#ifdef CONFIG_CMA

struct cma *cma_area; /* contiguous memory area for dma

allocations */

#endif

/* arch specific additions */

struct dev_archdata archdata;

struct device_node *of_node; /* associated device tree node */

dev_t devt; /* dev_t, creates the sysfs "dev" */

u32 id; /* device instance */

spinlock_t devres_lock;

struct list_head devres_head;

struct klist_node knode_class;

struct class *class;

const struct attribute_group **groups; /* optional groups */

//必须实现，当设备从内核移除时会调用此函数

void (*release)(struct device *dev);

};

设备的注册及移除：

device_register(struct device *dev);

device_unregister(struct device *dev);

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驱动：

struct device_driver {

const char *name; //驱动的名字

struct bus_type *bus; //驱动需要关联的总线

struct module *owner;

const char *mod_name; /* used for built-in modules */

bool suppress_bind_attrs; /* disables bind/unbind via sysfs */

const struct of_device_id *of_match_table;

int (*probe) (struct device *dev); //匹配成功，内核自动调用probe

int (*remove) (struct device *dev); //移除驱动时会自动调用remove

void (*shutdown) (struct device *dev);

int (*suspend) (struct device *dev, pm_message_t state);

int (*resume) (struct device *dev);

const struct attribute_group **groups;

const struct dev_pm_ops *pm;

//很重要

struct driver_private *p;

};

驱动的注册及移除：

int driver_register(struct device_driver *drv)

int driver_unregister(struct device_driver *drv)