对这段时间涉及到的Linux内核中重要结构体和宏的研究总结

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对这段时间涉及到的Linux内核中重要结构体和宏的研究总结

1.structdevice

2.klist_node

3.structkref

4.struct class

5.device_driver

6.device_node

7.of_device_id

8.platform_driver

9.platform_device

10.platform_match

11.input_device

12.iio_channel

13.iio_chan_spec

14.list_for_each_entry

1.struct device

/***struct device - The basic device structure //基本设备结构体*@parent: The device's "parent" device, the device to whichit is attached.//从属于*In most cases, a parent device is some sort of bus orhost //一般是总线或者主控制器*controller. If parent is NULL, the device, is a top-level device,*which is not usually what you want.//父空，则它就是顶层设备，通常不是你想要的*@p: Holds the private data of the driver core portions of thedevice.*See the comment of the struct device_private for detail.*@kobj: A top-level, abstract class from which other classes arederived.*@init_name: Initial name of the device.*@type: The type of device.*This identifies the device type and carries type-specific*information.*@mutex: Mutex to synchronize calls to its driver.*@bus: Type of bus device is on.*@driver: Which driver has allocated this*@platform_data: Platform data specific to the device.*Example: For devices on custom boards, as typical of embedded*and SOC based hardware, Linux often uses platform_data to point*to board-specific structures describing devices and how they*are wired. That can include what ports are available, chip*variants, which GPIO pins act in what additional roles, and so*on. This shrinks the "Board Support Packages" (BSPs) and*minimizes board-specific #ifdefs in drivers.*@power: For device power management.*See Documentation/power/devices.txt for details.*@pm_domain: Provide callbacks that are executed during systemsuspend,*hibernation, system resume and during runtime PM transitions*along with subsystem-level and driver-level callbacks.*@pins: For device pin management.* SeeDocumentation/pinctrl.txt for details.*@numa_node: NUMA node this device is close to.*@dma_mask: Dma mask (if dma'ble device).*@coherent_dma_mask: Like dma_mask, but for alloc_coherent mapping asnot all*hardware supports 64-bit addresses for consistent allocations*such descriptors.*@dma_parms: A low level driver may set these to teach IOMMU codeabout*segment limitations.*@dma_pools: Dma pools (if dma'ble device).*@dma_mem: Internal for coherent mem override.*@archdata: For arch-specific additions.*@of_node: Associated device tree node.*@acpi_node: Associated ACPI device node.*@devt: For creating the sysfs "dev".*@id: device instance*@devres_lock: Spinlock to protect the resource of the device.*@devres_head: The resources list of the device.*@knode_class: The node used to add the device to the class list.*@class: The class of the device.*@groups: Optional attribute groups.*@release: Callback to free the device after all references have*gone away. This should be set by the allocator of the*device (i.e. the bus driver that discovered the device).**At the lowest level, every device in a Linux system is represented byan*instance of struct device. The device structure contains theinformation*that the device model core needs to model the system. Mostsubsystems,*however, track additional information about the devices they host. Asa*result, it is rare for devices to be represented by bare devicestructures;*instead, that structure, like kobject structures, is usually embeddedwithin*a higher-level representation of the device.*/struct device {    @1.structdevice *parent;//设备从属于父，一般父为总线或者主机控制器    @2.structdevice_private *p; //用来保存设备的核心部分私有数据    platform_set_drvdata(structplatform*pdev, void*ddata );    本质就是pdev->dev->p= ddata;    @3.structkobject kobj; A top-level, abstract(抽象)class from which other classes are derived（起源，导出，衍生）.    @4.constchar *init_name; /* initial name of the device，设备初始化名，*    init_name，该设备的名称，用于platform_match时和平台总线驱动匹配。          注1：在设备模型中，名称是一个非常重要的变量，任何注册到内核中的设备，都必须有一个合法的名称，可以在初始化时给出，也可以由内核根据“busname + device ID”的方式创造    @5.conststruct device_type *type;    @6.structmutex mutex; /* mutex to synchronize calls to    * its driver.    */    @7.structbus_type *bus; /* type of bus device is on，platform,iic,spi..*/    @8.structdevice_driver *driver; /* which driver has allocated this    device device_driver?*/    @9.void *platform_data; /*Platform specific data, device    core doesn't touch it平台特殊数据*/    *Example: For devices on custom boards, as typical of embedded    *and SOC based hardware, Linux often uses platform_data to point    *to board-specific structures describing devices and how they    *are wired. That can include what ports are available, chip    *variants, which GPIO pins act in what additional roles, and so    *on. This shrinks the "Board Support Packages" (BSPs) and    *minimizes board-specific #ifdefs in drivers.    @10.structdev_pm_info power;//电源管理SeeDocumentation/power/devices.txt for details    @11.structdev_pm_domain *pm_domain;    #ifdefCONFIG_PINCTRL    @12.structdev_pin_info *pins;For device pin management.    * SeeDocumentation/pinctrl.txt for details.    #endif    #ifdefCONFIG_NUMA    @13.int numa_node; /*NUMA node this device is close to */    #endif    @14.u64 *dma_mask; /*dma mask (if dma'able device) */    @15.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. */    @16.structdevice_dma_parameters *dma_parms;    @17.structlist_head dma_pools; /* dma pools (if dma'ble) */    如果需要有某种数据结构的双向队列，就在这种结构内部放一个list_head数据结构成员。    @18.structdma_coherent_mem *dma_mem; /* internal for coherent mem    override */    #ifdefCONFIG_DMA_CMA    @19.structcma *cma_area; /* contiguous memory area for dma    allocations */    #endif    /*arch specific additions */    @20.structdev_archdata archdata;//Forarch-specific additions.    @21.structdevice_node *of_node; /* associated device tree node 设备树节点*/    @22.structacpi_dev_node acpi_node; /* associated ACPI device node */    @23.dev_t devt; /*dev_t, creates the sysfs "dev" */    typedefu_long dev_t;    @24.u32 id; /*device instance（实例）*/    设备资源管理自旋锁    @26.structlist_head devres_head; //设备资源管理链表，参照蜗窝科技http://www.wowotech.net/tag/devres    @27.structklist_node knode_class; //内核    @28.structclass *class; //设备属于的类，都有哪些类？    @29.conststruct attribute_group **groups; /* optional groups Optionalattribute groups */    @30.void (*release)(structdevice *dev);    Callbackto free the device after all references have    *gone away. Thisshould be setby the allocator of the    *device (i.e. the bus driver that discovered the device).    @31.structiommu_group *iommu_group;};

2.klist_nodde

struct klist_node {    void *n_klist; /*never access directly */    structlist_head n_node;    structkref n_ref;};

3.kref

structkref {atomic_trefcount; //引用计数};

4.struct class

【释疑解惑】   代码中出现的 class指的是 设备类（deviceclasses），是对于设备的高级抽象。但实际上class也是一个结构体，只不过class结构体在声明时是按照类的思想来组织其成员的。   运用class，可以让用户空间的程序根据自己要处理的事情来调用设备，而不是根据设备被接入到系统的方式或设备的工作原理来调用。   class 结构体的原型和相关描述可以在linux-4.3/include/linux/device.h中找到，内容如下：structclass {        const char               *name;     // 类名称       struct module          *owner;    // 类所属的模块，比如usb模块、led模块等       structclass_attribute              *class_attrs;        //类所添加的属性       const struct attribute_group   **dev_groups;    // 类所包含的设备所添加的属性       struct kobject                         *dev_kobj;        // 用于标识类所包含的设备属于块设备还是字符设备       int (*dev_uevent)(struct device *dev, structkobj_uevent_env *env);    // 用于在设备发出uevent消息时添加环境变量       char *(*devnode)(struct device *dev, umode_t*mode);    // 设备节点的相对路径名       void (*class_release)(struct class *class);   // 类被释放时调用的函数       void (*dev_release)(struct device *dev);   // 设备被释放时调用的函数       int (*suspend)(struct device *dev, pm_message_tstate);    // 设备休眠时调用的函数       int (*resume)(struct device *dev);    //设备被唤醒时调用的函数       const struct kobj_ns_type_operations *ns_type;       const void *(*namespace)(struct device *dev);       const struct dev_pm_ops *pm;    //用于电源管理的函数       struct subsys_private *p;     // 指向class_private结构的指针};

5.device_driver

/***struct device_driver - The basic device driver structure*@name: Name of the device driver.*@bus: The bus which the device of this driver belongs to.*@owner: The module owner.*@mod_name: Used for built-in modules.*@suppress_bind_attrs: Disables bind/unbind via sysfs.*@of_match_table: The open firmware table.*@acpi_match_table: The ACPI match table.*@probe: Called to query the existence of a specific device,* whetherthis driver can work with it, and bind the driver* toa specific device.*@remove: Called when the device is removed from the system to* unbinda device from this driver.*@shutdown: Called at shut-down time to quiesce the device.*@suspend: Called to put the device to sleep mode. Usually to a* lowpower state.*@resume: Called to bring a device from sleep mode.*@groups: Default attributes that get created by the driver core* automatically.*@pm: Power management operations of the device which matched* thisdriver.*@p: Driver core's private data, no one other than the driver* corecan touch this.**The device driver-model tracks all of the drivers known to thesystem.*The main reason for this tracking is to enable the driver core tomatch*up drivers with new devices. Once drivers are known objects withinthe*system, however, a number of other things become possible. Devicedrivers*can export information and configuration variables that areindependent*of any specific device.*/struct device_driver {    constchar *name; //设备驱动名,用于platform_match时和平台设备匹配    structbus_type *bus; //总线类型    structmodule *owner;    constchar *mod_name; /* used for built-in modules */    boolsuppress_bind_attrs; /* disables bind/unbind via sysfs */    conststruct of_device_id *of_match_table; //Theopen firmware table.    conststruct acpi_device_id *acpi_match_table; //The ACPI match table.    int(*probe) (struct device *dev);//probe函数，平台入口函数，注意形参，写驱动时提取设备信息    int(*remove) (struct device *dev);    void(*shutdown) (struct device *dev);    int(*suspend) (struct device *dev, pm_message_t state);    int(*resume) (struct device *dev);    conststruct attribute_group **groups;//Defaultattributes that get created by the driver core automatically.    conststruct dev_pm_ops *pm;//Powermanagement operations of the device which matched this driver.，电源管理    structdriver_private *p; //这里也可以保存驱动似有数据};

6.struct device_node

struct  device_node {    constchar *name;    constchar *type;    phandlephandle;    constchar *full_name;    struct property*properties;    struct property*deadprops; /* removed properties */    struct device_node*parent;    struct device_node*child;    struct device_node*sibling;    struct device_node*next; /* next device of same type */    struct device_node*allnext; /* next in list of all nodes */    struct proc_dir_entry*pde; /* this node's proc directory */    struct krefkref;    unsignedlong _flags;    void *data;    #ifdefined(CONFIG_SPARC)    constchar *path_component_name;    unsignedint unique_id;    structof_irq_controller *irq_trans;    #endif};

7.of_device_id

/**Struct used for matching a device用于平台驱动中从dts的,compatible属性值去匹配一个平台设备*/struct of_device_id{    char name[32];    char type[32];    char compatible[128];    constvoid *data;};

9.platform_driver

struct platform_driver {    int(*probe)(struct platform_device *);    int(*remove)(struct platform_device *);    void(*shutdown)(struct platform_device *);    int(*suspend)(struct platform_device *, pm_message_t state);    int(*resume)(struct platform_device *);    structdevice_driver driver;    conststruct platform_device_id *id_table; //用于platform_match    详见http://blog.csdn.net/mcgrady_tracy/article/details/38980991};

10.platform_device

struct platform_device {    constchar *name;    int id;    bool id_auto;    structdevice dev;    u32 num_resources;    structresource *resource;    conststruct platform_device_id *id_entry;    /*MFD cell pointer */    structmfd_cell *mfd_cell;    /*arch specific additions */    structpdev_archdata archdata;};

11.platform_match

各种总线的匹配方法及函数详见：http://blog.csdn.net/fanqipin/article/details/8153053

12.input_device

/***struct input_dev - represents an input device*@name: name of the device*@phys: physical path to the device in the system hierarchy（分层）*@uniq: unique identification code for the device (if device has it)*@id: id of the device (struct input_id)*@propbit: bitmap of device properties and quirks*@evbit: bitmap of types of events supported by the device (EV_KEY,* EV_REL,etc.)*@keybit: bitmap of keys/buttons this device has*@relbit: bitmap of relative axes for the device*@absbit: bitmap of absolute axes for the device*@mscbit: bitmap of miscellaneous events supported by the device*@ledbit: bitmap of leds present on the device*@sndbit: bitmap of sound effects supported by the device*@ffbit: bitmap of force feedback effects supported by the device*@swbit: bitmap of switches present on the device*@hint_events_per_packet: average number of events generated by the* devicein a packet (between EV_SYN/SYN_REPORT events). Used by* eventhandlers to estimate size of the buffer needed to hold* events.*@keycodemax: size of keycode table*@keycodesize: size of elements in keycode table*@keycode: map of scancodes to keycodes for this device*@getkeycode: optional legacy method to retrieve current keymap.*@setkeycode: optional method to alter current keymap, used toimplement* sparsekeymaps. If not supplied default mechanism will be used.* Themethod is being called while holding event_lock and thus must* notsleep*@ff: force feedback structure associated with the device if device* supportsforce feedback effects*@repeat_key: stores key code of the last key pressed; used toimplement* softwareautorepeat*@timer: timer for software autorepeat*@rep: current values for autorepeat parameters (delay, rate)*@mt: pointer to multitouch state*@absinfo: array of &struct input_absinfo elements holdinginformation* aboutabsolute axes (current value, min, max, flat, fuzz,* resolution)*@key: reflects current state of device's keys/buttons*@led: reflects current state of device's LEDs*@snd: reflects current state of sound effects*@sw: reflects current state of device's switches*@open: this method is called when the very first user calls* input_open_device().The driver must prepare the device* tostart generating events (start polling thread,* requestan IRQ, submit URB, etc.)*@close: this method is called when the very last user calls* input_close_device().*@flush: purges the device. Most commonly used to get rid of force* feedbackeffects loaded into the device when disconnecting* fromit*@event: event handler for events sent _to_ the device, like EV_LED* orEV_SND. The device is expected to carry out the requested* action(turn on a LED, play sound, etc.) The call is protected* by@event_lock and must not sleep*@grab: input handle that currently has the device grabbed (via* EVIOCGRABioctl). When a handle grabs a device it becomes sole* recipientfor all input events coming from the device*@event_lock: this spinlock is is taken when input core receives* andprocesses a new event for the device (in input_event()).* Codethat accesses and/or modifies parameters of a device* (suchas keymap or absmin, absmax, absfuzz, etc.) after device* hasbeen registered with input core must take this lock.*@mutex: serializes calls to open(), close() and flush() methods*@users: stores number of users (input handlers) that opened this* device.It is used by input_open_device() and input_close_device()* tomake sure that dev->open() is only called when the first* useropens device and dev->close() is called when the very* lastuser closes the device*@going_away: marks devices that are in a middle of unregistering and* causesinput_open_device*() fail with -ENODEV.*@dev: driver model's view of this device*@h_list: list of input handles associated with the device. When* accessingthe list dev->mutex must be held*@node: used to place the device onto input_dev_list*@num_vals: number of values queued in the current frame*@max_vals: maximum number of values queued in a frame*@vals: array of values queued in the current frame*@devres_managed: indicates that devices is managed with devresframework* andneeds not be explicitly unregistered or freed.*/struct input_dev {    @1const char *name; //输入设备名，和device->name有什么联系device_driver->nameplatform_divice->name,platform_driver->name ;    @2const char *phys;//设备在system层的物理路径，这和在/sys/device/xxx文件夹名有关吗？    @3const char *uniq;    @4struct input_id id;    structinput_id {    __u16bustype;    __u16vendor;    __u16product;    __u16version;    };    @5unsigned long propbit[BITS_TO_LONGS(INPUT_PROP_CNT)];    @6unsigned long evbit[BITS_TO_LONGS(EV_CNT)]; //支持的事件类型    __set_bit(EV_KEY,...,input->evbit);    //事件类型下产生的数据具体上报方法    @7unsigned long keybit[BITS_TO_LONGS(KEY_CNT)];    @8unsigned long relbit[BITS_TO_LONGS(REL_CNT)];    @9unsigned long absbit[BITS_TO_LONGS(ABS_CNT)];    @10unsigned long mscbit[BITS_TO_LONGS(MSC_CNT)];    @11unsigned long ledbit[BITS_TO_LONGS(LED_CNT)];    @12unsigned long sndbit[BITS_TO_LONGS(SND_CNT)];    @13unsigned long ffbit[BITS_TO_LONGS(FF_CNT)];    @14unsigned long swbit[BITS_TO_LONGS(SW_CNT)];    @15unsigned int hint_events_per_packet;    @16unsigned int keycodemax;    @17unsigned int keycodesize; //size of elements（元素）inkeycode table    @18void *keycode;    @19int (*setkeycode)(struct input_dev *dev,    const struct input_keymap_entry *ke,    unsigned int *old_keycode);    @20int (*getkeycode)(struct input_dev *dev,    struct input_keymap_entry *ke);    @21struct ff_device *ff;    //按键自动重复机制？    @22unsigned int repeat_key; //stores key code of the last key pressed; used toimplement （实施）softwareautorepeat    @23structtimer_list timer;//timer for software autorepeat    @24intrep[REP_CNT]; //currentvalues for autorepeat parameters (delay, rate)    @25struct input_mt *mt;    @26struct input_absinfo *absinfo;    @27unsigned long key[BITS_TO_LONGS(KEY_CNT)];    //reflects current state ofdevice's keys/buttons    @28unsigned long led[BITS_TO_LONGS(LED_CNT)];    //reflectscurrent state of device's LEDs    @29unsigned long snd[BITS_TO_LONGS(SND_CNT)];    //reflectscurrent state of sound effects    @30unsigned long sw[BITS_TO_LONGS(SW_CNT)];    //reflectscurrent state of device's switches    @31int (*open)(struct input_dev *dev);    @32void (*close)(struct input_dev *dev);    @33int (*flush)(struct input_dev *dev, struct file *file);    @34int (*event)(struct input_dev *dev,unsigned int type, unsigned int code, int value);    eventhandler for events sent _to_ the device, like EV_LED    * orEV_SND. The device is expected to carry out the requested    * action(turn on a LED, play sound, etc.) The call is protected    * by@event_lock and must not sleep    @35struct input_handle __rcu *grab;    @grab: input handle that currently has the device grabbed (via    EVIOCGRABioctl). When a handle grabs a device it becomes sole    recipient（唯一的容器）forall input events coming fr om the device    @36spinlock_t event_lock;    @37struct mutex mutex;    @38unsigned int users; //存储打开该设备的用户数量    @39bool going_away;    @40struct device dev; //保存一个设备    @41struct list_head h_list;    @42structlist_head node; //用于把该设备放入input_dev_list输入设备链表上    @43unsigned int num_vals;    @44unsigned int max_vals;    @45struct input_value *vals;    @46bool devres_managed; //资源管理};

13.iio_channel

/***struct iio_channel - everything needed for a consumer to use achannel*@indio_dev: Device on which the channel exists. //*@channel: Full description of the channel.//详细描述通道*@data: Data about the channel used by consumer. //用户使用的通道数据*/struct iio_channel {    structiio_dev *indio_dev;    conststruct iio_chan_spec *channel;    void*data;};

14.iio_chan_spec

/***struct iio_chan_spec - specification of a single channel*@type: What type of measurement is the channel making.*@channel: What number do we wish to assign the channel.*@channel2: If there is a second number for a differential* channelthen this is it. If modified is set then the* valuehere specifies the modifier.*@address: Driver specific identifier.*@scan_index: Monotonic index to give ordering in scans when read* froma buffer.*@scan_type: Sign: 's' or 'u' to specify signed or unsigned* realbits: Numberof valid bits of data* storage_bits: Realbits+ padding* shift: Shiftright by this before masking out* realbits.* endianness: littleor big endian*@info_mask: What information is to be exported about this channel.* Thisincludes calibbias, scale etc.*@info_mask_separate: What information is to be exported that isspecific to* thischannel.*@info_mask_shared_by_type: What information is to be exported that isshared* byall channels of the same type.*@event_mask: What events can this channel produce.*@ext_info: Array of extended info attributes for this channel.* Thearray is NULL terminated, the last element should* haveits name field set to NULL.*@extend_name: Allows labeling of channel attributes with an* informativename. Note this has no effect codes etc,* unlikemodifiers.*@datasheet_name: A name used in in-kernel mapping of channels. Itshould* correspondto the first name that the channel is referred* toby in the datasheet (e.g. IND), or the nearest* possiblecompound name (e.g. IND-INC).*@modified: Does a modifier apply to this channel. What these are* dependson the channel type. Modifier is set in* channel2.Examples are IIO_MOD_X for axial sensors about* the'x' axis.*@indexed: Specify the channel has a numerical index. If not,* thechannel index number will be suppressed for sysfs* attributesbut not for event codes.*@output: Channel is output.*@differential: Channel is differential.*/struct iio_chan_spec {    enumiio_chan_type type;    int channel;    int channel2;    unsignedlong address;    int scan_index;    struct{    char sign;    u8 realbits;    u8 storagebits;    u8 shift;    enumiio_endian endianness;    }scan_type;    long info_mask;    long info_mask_separate;    long info_mask_shared_by_type;    long event_mask;    conststruct iio_chan_spec_ext_info *ext_info;    constchar *extend_name;    constchar *datasheet_name;    Aname used in in-kernel mapping of channels. It should    * correspondto the first name that the channel is referred    * toby in the datasheet (e.g. IND), or the nearest    * possiblecompound name (e.g. IND-INC).    unsigned modified:1;    unsigned indexed:1;    unsigned output:1;    unsigned differential:1;};

15.list_for_each_entry

    在Linux内核源码中，经常要对链表进行操作，其中一个很重要的宏是list_for_each_entry：意思大体如下：        假设下面y有几个结点，则第一个member代表head，list_for_each_entry的作用就是循环遍历每一个pos中的member子项。list_for_each_entry应用：        它实际上是一个 for循环，利用传入的 pos作为循环变量，从表头head开始，逐项向后（next方向）移动pos，直至又回head（prefetch()可以不考虑，用于预取以提高遍历速度）。 在程序中的使用如下：list_for_each_entry（pos, head,member）{       ………………      addr=    pos; //对返回值pos的操作，这样更容易去理解list_for_each_entry，可以把它看作for()循环……………input_device->name，和device->name,device_driver->name,platform_divice->name,platform_driver->name``有什么联系?

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