Linux下USB Gadget驅(qū)動(dòng)框架簡(jiǎn)介

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1、一、USB系統(tǒng)簡(jiǎn)介1.設(shè)備狀態(tài)的轉(zhuǎn)換2.USB設(shè)備邏輯組織在USB協(xié)議中，接口（interface）由一個(gè)或多個(gè)端點(diǎn)組成，代表一個(gè)基本功能單元。配置（Configuration）由一個(gè)或多個(gè)接口組成。一個(gè)USB設(shè)備可以具有一個(gè)或多個(gè)配置。3.Linux下USB驅(qū)動(dòng)整體框架Linux下USB設(shè)備側(cè)驅(qū)動(dòng)程序分為三個(gè)層次：?UDCDrivers直接訪問(wèn)硬件，控制Usb設(shè)備和Host間的底層通信，向上層提供硬件相關(guān)操作的回調(diào)函數(shù)。?GadgetAPI是UDCDrivers回調(diào)函數(shù)的封裝。?Gadgetd

2、rivers是USB設(shè)備具體功能的實(shí)現(xiàn)。4.Setup過(guò)程介紹USB協(xié)議規(guī)定每個(gè)DEVICE必須有一個(gè)編號(hào)為0的CONTROL端點(diǎn)，此端點(diǎn)在RESET后即可用，無(wú)需HOST做任何配置。Host通過(guò)端點(diǎn)0完成SETUP過(guò)程。以下是fastboot的setup過(guò)程：??SETUP(0xB4)ADDR(0)ENDP(0)Data(8006000100004000)IN(0x96)ADDR(0)ENDP(0)Data(__00:120100020

3、0000040B40BFF0F00010101__16:0101)??SETUP(0xB4)ADDR(0)ENDP(0)Data(0005040000000000)?SETUP(0xB4)ADDR(4)ENDP(0)Data(8006000100001200)IN(0x96)ADDR(4)ENDP(0)Data(__00:1201000200000040B40BFF0F00010101__16:0101)?

4、DESCRIPTOR:CONFIGURATION>SETUP(0xB4)ADDR(4)ENDP(0)Data(8006000200000900)IN(0x96)ADDR(4)ENDP(0)Data(090220000101018080)?SETUP(0xB4)ADDR(4)ENDP(0)Data(800600030000FF00)IN(0x96)ADDR(4)ENDP(0)Data(04030904)?SET

5、UP(0xB4)ADDR(4)ENDP(0)Data(800601030904FF00)IN(0x96)ADDR(4)ENDP(0)Data(__00:1203660061007300740062006F006F00__16:7400)?SETUP(0xB4)ADDR(4)ENDP(0)Data(800600020000FF00)IN(0x96)ADDR(4)ENDP(0)Data(__00:09022000010101808009040

6、00002FF42__16:03000705820200020007050102000201)?SETUP(0xB4)ADDR(4)ENDP(0)Data(800600030000FF00)IN(0x96)ADDR(4)ENDP(0)Data(04030904)?SETUP(0xB4)ADDR(4)ENDP(0)Data(800601030904FF00)IN(0x96)ADDR(4)ENDP(0)Data(

7、__00:1203660061007300740062006F006F00__16:7400)?SETUP(0xB4)ADDR(4)ENDP(0)Data(8006000100001200)IN(0x96)ADDR(4)ENDP(0)Data(__00:1201000200000040B40BFF0F00010101__16:0101)?SETUP(0xB4)ADDR(4)ENDP(0)Data

8、(8006000200000900)IN(0x96)ADDR(4)ENDP(0)Data(090220000101018080)?SETUP(0xB4)ADDR(4)ENDP(0)Data(8006000200002000)IN(0x96)ADDR(4)ENDP(0)Data(__00:0902200001010180800904000002FF42__16:03000705820200020007050102000201)?