前面我們學(xué)習(xí)了USB 驅(qū)動的一個描述符，下面來學(xué)習(xí) USB 驅(qū)動的幾個重要數(shù)據(jù)結(jié)構(gòu)

一、struct usb_interface??接口函數(shù)

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struct?usb_interface??

{??

???????????

?????????struct?usb_host_interface?*altsetting;??

??

?????????struct?usb_host_interface?*cur_altsetting;????????

?????????unsigned?num_altsetting;??????????

??

?????????int?minor;????????????????????????

?????????enum?usb_interface_condition?condition;???????????

?????????unsigned?is_active:1;?????????????

?????????unsigned?needs_remote_wakeup:1;???

??

?????????struct?device?dev;????????????????

?????????struct?device?*usb_dev;???????????

?????????int?pm_usage_cnt;?????????????????

};??

? ? struct usb_interface中的struct usb_host_interface *cur_altsetting成員，表示當(dāng)前正在使用的設(shè)置

1、struct usb_host_interface?

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struct?usb_host_interface???

{??

?????????struct?usb_interface_descriptor?desc;//usb描述符，主要有四種usb描述符，設(shè)備描述符，配置描述符，接口描述符和端點描述符，協(xié)議里規(guī)定一個usb設(shè)備是必須支持這四大描述符的。??

?????????????????????????????????//usb描述符放在usb設(shè)備的eeprom里邊??

?????????/*?array?of?desc.bNumEndpoint?endpoints?associated?with?this?

??????????*?interface?setting.?these?will?be?in?no?particular?order.?

??????????*/??

?????????struct?usb_host_endpoint?*endpoint;//這個設(shè)置所使用的端點??

??

?????????char?*string;???????????/*?iInterface?string,?if?present?*/??

?????????unsigned?char?*extra;???/*?Extra?descriptors?*/關(guān)于額外描述符??

?????????int?extralen;??

};??

? ? ? ?具體到接口描述符，它當(dāng)然就是描述接口本身的信息的。一個接口可以有多個設(shè)置，使用不同的設(shè)置，描述接口的信息會有些不同，所以接口描述符并沒有放在struct usb_interface結(jié)構(gòu)里，而是放在表示接口設(shè)置的struct usb_host_interface結(jié)構(gòu)里。

二、struct usb_host_endpoint ?端點函數(shù)

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struct?usb_host_endpoint???

{??

?????????struct?usb_endpoint_descriptor?desc;??

?????????struct?list_head????????????????urb_list;//端點要處理的urb隊列.urb是usb通信的主角，設(shè)備中的每個端點都可以處理一個urb隊列.要想和你的usb通信，就得創(chuàng)建一個urb，并且為它賦好值，??

???????????????????????????????????//交給咱們的usb?core，它會找到合適的host?controller，從而進行具體的數(shù)據(jù)傳輸??

?????????void????????????????????????????*hcpriv;//這是提供給HCD（host?controller?driver）用的??

?????????struct?ep_device????????????????*ep_dev;????????/*?For?sysfs?info?*/??

??

?????????unsigned?char?*extra;???/*?Extra?descriptors?*/??

?????????int?extralen;??

};??

三、struct usb_device 設(shè)備函數(shù)

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struct?usb_device?{??

????int?devnum;?????????//devnum只是usb設(shè)備在一條usb總線上的編號.一條usb_bus_type類型的總線上最多可以連上128個設(shè)備??

????char?devpath?[16];???/*?Use?in?messages:?/port/port/...*/??//對于root?hub.會將dev->devpath[0]=’0’??

????enum?usb_device_state???state;??//設(shè)備的狀態(tài)Attached，Powered，Default，Address，Configured，Suspended；??

???????????????????????????????//Attached表示設(shè)備已經(jīng)連接到usb接口上了，是hub檢測到設(shè)備時的初始狀態(tài)。那么這里所謂的USB_STATE_NOTATTACHED就是表示設(shè)備并沒有Attached。??

???????????????????????????????//Address狀態(tài)表示主機分配了一個唯一的地址給設(shè)備，此時設(shè)備可以使用缺省管道響應(yīng)主機的請求??

???????????????????????????????//Configured狀態(tài)表示設(shè)備已經(jīng)被主機配置過了，也就是協(xié)議里說的處理了一個帶有非0值的SetConfiguration()請求，此時主機可以使用設(shè)備提供的所有功能??

???????????????????????????????//Suspended掛起狀態(tài)，為了省電，設(shè)備在指定的時間內(nèi)，3ms吧，如果沒有發(fā)生總線傳輸，就要進入掛起狀態(tài)。此時，usb設(shè)備要自己維護包括地址、配置在內(nèi)的信息???????????????

??

????enum?usb_device_speed???speed;??/*?high/full/low?(or?error)?*/??

??????

????struct?usb_tt???*tt;????????????//如果一個高速設(shè)備里有這么一個TT，那么就可以連接低速/全速設(shè)備，如不然，那低速/全速設(shè)備沒法用，只能連接到OHCI/UHCI那邊出來的hub口里。??

????int?????????????ttport;?????????//如果一個高速設(shè)備里有這么一個TT，那么就可以連接低速/全速設(shè)備，如不然，那低速/全速設(shè)備沒法用，只能連接到OHCI/UHCI那邊出來的hub口里。??

??????

????unsigned?int?toggle[2];?????????/*?one?bit?for?each?endpoint?????//他實際上就是一個位圖.IN方向的是toggle[0].OUT方向的是toggle[1].其實,這個數(shù)組中的每一位表示ep的toggle值?

?????????????????????????????????????????????*?([0]?=?IN,?[1]?=?OUT)?*/它里面的每一位表示的就是每個端點當(dāng)前發(fā)送或接收的數(shù)據(jù)包是DATA0還是DATA1??

??????

????struct?usb_device?*parent;??????/*?our?hub,?unless?we're?the?root?*/??

??????????????????????????????//USB設(shè)備是從Root?Hub開始，一個一個往外面連的，比如Root?Hub有4個口，每個口連一個USB設(shè)備，比如其中有一個是Hub，那么這個Hub有可以繼續(xù)有多個口，于是一級一級的往下連，??

???????????????????????????????//最終連成了一棵樹。??

????struct?usb_bus?*bus;????????????/*?Bus?we're?part?of?*/設(shè)備所在的總線??

????struct?usb_host_endpoint?ep0;???//端點0的特殊地位決定了她必將受到特殊的待遇，在struct?usb_device對象產(chǎn)生的時候它就要初始化??

??????

????struct?device?dev;??????????????/*?Generic?device?interface?*/嵌入到struct?usb_device結(jié)構(gòu)里的struct?device結(jié)構(gòu)??

??????

????struct?usb_device_descriptor?descriptor;/*?Descriptor?*/設(shè)備描述符，此結(jié)構(gòu)體的bMaxPacketSize0?filed保存了端點0的maximum?packet?size??

????struct?usb_host_config?*config;?//設(shè)備擁有的所有配置??

??????

????struct?usb_host_config?*actconfig;//設(shè)備正在使用的配置??

????struct?usb_host_endpoint?*ep_in[16];//ep_in[16]，359行，ep_out[16]，除了端點0，一個設(shè)備即使在高速模式下也最多只能再有15個IN端點和15個OUT端點，端點0太特殊了，??

????struct?usb_host_endpoint?*ep_out[16];//對應(yīng)的管道是Message管道，又能進又能出特能屈能伸的那種，所以這里的ep_in和ep_out數(shù)組都有16個值??

??????

????char?**rawdescriptors;??????????/*?Raw?descriptors?for?each?config?*/??

??????

????unsigned?short?bus_mA;??????????/*?Current?available?from?the?bus?*/這個值是在host?controller的驅(qū)動程序中設(shè)置的，通常來講，計算機的usb端口可以提供500mA的電流??

????u8?portnum;?????????????????????//不管是root?hub還是一般的hub，你的USB設(shè)備總歸要插在一個hub的端口上才能用，portnum就是那個端口號。??

????u8?level;???????????????????????//層次，也可以說是級別，表征usb設(shè)備樹的級連關(guān)系。Root?Hub的level當(dāng)然就是0，其下面一層就是level?1，再下面一層就是level?2，依此類推??

??????

????unsigned?discon_suspended:1;????/*?Disconnected?while?suspended?*/??

????unsigned?have_langid:1;?????????/*?whether?string_langid?is?valid?*/??

????int?string_langid;??????????????/*?language?ID?for?strings?*/??

??????

????/*?static?strings?from?the?device?*/??

????char?*product;??????????????????/*?iProduct?string,?if?present?*/??

????char?*manufacturer;?????????????/*?iManufacturer?string,?if?present?*/??

????char?*serial;???????????????????/*?iSerialNumber?string,?if?present?*/??

????????????????????????????????????//分別用來保存產(chǎn)品、廠商和序列號對應(yīng)的字符串描述符信息??

????struct?list_head?filelist;??

#ifdef?CONFIG_USB_DEVICE_CLASS??

????struct?device?*usb_classdev;??

#endif??

#ifdef?CONFIG_USB_DEVICEFS??

????struct?dentry?*usbfs_dentry;????/*?usbfs?dentry?entry?for?the?device?*/??

#endif??

????/*?

????*?Child?devices?-?these?can?be?either?new?devices?

????*?(if?this?is?a?hub?device),?or?different?instances?

????*?of?this?same?device.?

????*?

????*?Each?instance?needs?its?own?set?of?data?structures.?

????*/??

??????

????int?maxchild;???????????????????/*?Number?of?ports?if?hub?*/??

????struct?usb_device?*children[USB_MAXCHILDREN];??

??????

????int?pm_usage_cnt;???????????????/*?usage?counter?for?autosuspend?*/??

????u32?quirks;?????????????????????//quirk就是用來判斷這些有毛病的產(chǎn)品啥毛病的??

??????

#ifdef?CONFIG_PM??

????struct?delayed_work?autosuspend;?/*?for?delayed?autosuspends?*/??

????struct?mutex?pm_mutex;??????????/*?protects?PM?operations?*/??

??????

????unsigned?long?last_busy;????????/*?time?of?last?use?*/??

????int?autosuspend_delay;??????????/*?in?jiffies?*/??

??????

????unsigned?auto_pm:1;?????????????/*?autosuspend/resume?in?progress?*/??

????unsigned?do_remote_wakeup:1;????/*?remote?wakeup?should?be?enabled?*/??

????unsigned?autosuspend_disabled:1;?/*?autosuspend?and?autoresume?*/??

????unsigned?autoresume_disabled:1;??/*??disabled?by?the?user?*/??

#endif??

};??

四、struct usb_host_config 配置函數(shù)

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struct?usb_host_config?{??

????struct?usb_config_descriptor????desc;??

??????

????char?*string;?????????????

??????????????

????struct?usb_interface?*interface[USB_MAXINTERFACES];????????????//配置所包含的接口，這個數(shù)組的順序未必是按照配置里接口號的順序??

??????

?????????????

????struct?usb_interface_cache?*intf_cache[USB_MAXINTERFACES];????????//usb接口的緩存??

??????

????unsigned?char?*extra;?????

????int?extralen;??

}; ?

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