usb-Transfer/Transaction/Packet

本文详细解析了USB高速MSC协议中的View TransactionLevel抓包片段,具体分析了一次长度为3072Bytes的Transfer过程,其中包括6次Transaction,每次Transaction包含3个packet(IN/DATA0/ACK)。通过分析,展示了整个传输过程共传输了(31+512*6+13)Bytes的数据,耗时6个微帧。

usb high-speed msc协议抓包片段(View Transger Level,Hid Nak‘s/NRDY's’)如下:

一次长度为3072Bytes的Transfer。

本次Transfer中包含6次Transaction,每次Transaction包含3个packet(IN/DATA0/ACK)。


改用View Transaction Level(Hid Nak‘s/NRDY's’)可以看得更清楚。

整个传输一共传输(31+512*6+13)Bytes,耗时6个微帧。





#include "tusb_option.h" #if CFG_TUD_ENABLED #include "dcd.h" #include "tusb.h" #include "device/usbd_pvt.h" //--------------------------------------------------------------------+ // Callback weak stubs (called if application does not provide) //--------------------------------------------------------------------+ TU_ATTR_WEAK void dcd_edpt0_status_complete(uint8_t rhport, tusb_control_request_t const* request) { (void) rhport; (void) request; } //--------------------------------------------------------------------+ // MACRO CONSTANT TYPEDEF //--------------------------------------------------------------------+ #if CFG_TUSB_DEBUG >= CFG_TUD_LOG_LEVEL extern void usbd_driver_print_control_complete_name(usbd_control_xfer_cb_t callback); #endif enum { EDPT_CTRL_OUT = 0x00, EDPT_CTRL_IN = 0x80 }; typedef struct { tusb_control_request_t request; uint8_t* buffer; uint16_t data_len; uint16_t total_xferred; usbd_control_xfer_cb_t complete_cb; } usbd_control_xfer_t; tu_static usbd_control_xfer_t _ctrl_xfer; CFG_TUD_MEM_SECTION CFG_TUSB_MEM_ALIGN tu_static uint8_t _usbd_ctrl_buf[CFG_TUD_ENDPOINT0_SIZE]; //--------------------------------------------------------------------+ // Application API //--------------------------------------------------------------------+ // Queue ZLP status transaction static inline bool _status_stage_xact(uint8_t rhport, tusb_control_request_t const* request) { // Opposite to endpoint in Data Phase uint8_t const ep_addr = request->bmRequestType_bit.direction ? EDPT_CTRL_OUT : EDPT_CTRL_IN; return usbd_edpt_xfer(rhport, ep_addr, NULL, 0); } // Status phase bool tud_control_status(uint8_t rhport, tusb_control_request_t const* request) { _ctrl_xfer.request = (*request); _ctrl_xfer.buffer = NULL; _ctrl_xfer.total_xferred = 0; _ctrl_xfer.data_len = 0; return _status_stage_xact(rhport, request); } // Queue a transaction in Data Stage // Each transaction has up to Endpoint0's max packet size. // This function can also transfer an zero-length packet static bool _data_stage_xact(uint8_t rhport) { uint16_t const xact_len = tu_min16(_ctrl_xfer.data_len - _ctrl_xfer.total_xferred, CFG_TUD_ENDPOINT0_SIZE); uint8_t ep_addr = EDPT_CTRL_OUT; if (_ctrl_xfer.request.bmRequestType_bit.direction == TUSB_DIR_IN) { ep_addr = EDPT_CTRL_IN; if (xact_len) { TU_VERIFY(0 == tu_memcpy_s(_usbd_ctrl_buf, CFG_TUD_ENDPOINT0_SIZE, _ctrl_xfer.buffer, xact_len)); } } return usbd_edpt_xfer(rhport, ep_addr, xact_len ? _usbd_ctrl_buf : NULL, xact_len); } // Transmit data to/from the control endpoint. // If the request's wLength is zero, a status packet is sent instead. bool tud_control_xfer(uint8_t rhport, tusb_control_request_t const* request, void* buffer, uint16_t len) { _ctrl_xfer.request = (*request); _ctrl_xfer.buffer = (uint8_t*) buffer; _ctrl_xfer.total_xferred = 0U; _ctrl_xfer.data_len = tu_min16(len, request->wLength); if (request->wLength > 0U) { if (_ctrl_xfer.data_len > 0U) { TU_ASSERT(buffer); } // TU_LOG2(" Control total data length is %u bytes\r\n", _ctrl_xfer.data_len); // Data stage TU_ASSERT(_data_stage_xact(rhport)); } else { // Status stage TU_ASSERT(_status_stage_xact(rhport, request)); } return true; } //--------------------------------------------------------------------+ // USBD API //--------------------------------------------------------------------+ void usbd_control_reset(void); void usbd_control_set_request(tusb_control_request_t const* request); void usbd_control_set_complete_callback(usbd_control_xfer_cb_t fp); bool usbd_control_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t event, uint32_t xferred_bytes); void usbd_control_reset(void) { tu_varclr(&_ctrl_xfer); } // Set complete callback void usbd_control_set_complete_callback(usbd_control_xfer_cb_t fp) { _ctrl_xfer.complete_cb = fp; } // for dcd_set_address where DCD is responsible for status response void usbd_control_set_request(tusb_control_request_t const* request) { _ctrl_xfer.request = (*request); _ctrl_xfer.buffer = NULL; _ctrl_xfer.total_xferred = 0; _ctrl_xfer.data_len = 0; } // callback when a transaction complete on // - DATA stage of control endpoint or // - Status stage bool usbd_control_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t result, uint32_t xferred_bytes) { (void) result; // Endpoint Address is opposite to direction bit, this is Status Stage complete event if (tu_edpt_dir(ep_addr) != _ctrl_xfer.request.bmRequestType_bit.direction) { TU_ASSERT(0 == xferred_bytes); // invoke optional dcd hook if available dcd_edpt0_status_complete(rhport, &_ctrl_xfer.request); if (_ctrl_xfer.complete_cb) { // TODO refactor with usbd_driver_print_control_complete_name _ctrl_xfer.complete_cb(rhport, CONTROL_STAGE_ACK, &_ctrl_xfer.request); } return true; } if (_ctrl_xfer.request.bmRequestType_bit.direction == TUSB_DIR_OUT) { TU_VERIFY(_ctrl_xfer.buffer); memcpy(_ctrl_xfer.buffer, _usbd_ctrl_buf, xferred_bytes); TU_LOG_MEM(CFG_TUD_LOG_LEVEL, _usbd_ctrl_buf, xferred_bytes, 2); } _ctrl_xfer.total_xferred += (uint16_t) xferred_bytes; _ctrl_xfer.buffer += xferred_bytes; // Data Stage is complete when all request's length are transferred or // a short packet is sent including zero-length packet. if ((_ctrl_xfer.request.wLength == _ctrl_xfer.total_xferred) || (xferred_bytes < CFG_TUD_ENDPOINT0_SIZE)) { // DATA stage is complete bool is_ok = true; // invoke complete callback if set // callback can still stall control in status phase e.g out data does not make sense if (_ctrl_xfer.complete_cb) { #if CFG_TUSB_DEBUG >= CFG_TUD_LOG_LEVEL usbd_driver_print_control_complete_name(_ctrl_xfer.complete_cb); #endif is_ok = _ctrl_xfer.complete_cb(rhport, CONTROL_STAGE_DATA, &_ctrl_xfer.request); } if (is_ok) { // Send status TU_ASSERT(_status_stage_xact(rhport, &_ctrl_xfer.request)); } else { // Stall both IN and OUT control endpoint dcd_edpt_stall(rhport, EDPT_CTRL_OUT); dcd_edpt_stall(rhport, EDPT_CTRL_IN); } } else { // More data to transfer TU_ASSERT(_data_stage_xact(rhport)); } return true; } #endif
11-11
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