dwc_otg_qh Struct Reference

A Queue Head (QH) holds the static characteristics of an endpoint and maintains a list of transfers (QTDs) for that endpoint. More...

#include <dwc_otg_hcd.h>

Data Fields
uint8_t	ep_type
	Endpoint type.
uint8_t	ep_is_in
uint16_t	maxp
	wMaxPacketSize Field of Endpoint Descriptor.
uint8_t	dev_speed
	Device speed.
uint8_t	data_toggle
	Determines the PID of the next data packet for non-control transfers.
uint8_t	ping_state
	Ping state if 1.
dwc_otg_qtd_list	qtd_list
	List of QTDs for this QH.
dwc_hc *	channel
	Host channel currently processing transfers for this QH.
uint8_t	do_split
	Full/low speed endpoint on high-speed hub requires split.
uint8_t *	dw_align_buf
	Used instead of original buffer if it(physical address) is not dword-aligned.
dwc_dma_t	dw_align_buf_dma
dwc_list_link_t	qh_list_entry
	Entry for QH in either the periodic or non-periodic schedule.
Periodic schedule information
uint16_t	usecs
	Bandwidth in microseconds per (micro)frame.
uint16_t	interval
	Interval between transfers in (micro)frames.
uint16_t	sched_frame
	(micro)frame to initialize a periodic transfer.
uint16_t	start_split_frame
	(micro)frame at which last start split was initialized.
Descriptor DMA support
dwc_otg_host_dma_desc_t *	desc_list
	Descriptor List.
dwc_dma_t	desc_list_dma
	Descriptor List physical address.
uint32_t *	n_bytes
	Xfer Bytes array.
uint16_t	ntd
	Actual number of transfer descriptors in a list.
uint8_t	td_first
	First activated isochronous transfer descriptor index.
uint8_t	td_last
	Last activated isochronous transfer descriptor index.

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Detailed Description

A Queue Head (QH) holds the static characteristics of an endpoint and maintains a list of transfers (QTDs) for that endpoint.

A QH structure may be entered in either the non-periodic or periodic schedule.

Definition at line 261 of file dwc_otg_hcd.h.

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Field Documentation

uint8_t dwc_otg_qh::ep_type

Endpoint type.

One of the following values:

• UE_CONTROL
• UE_BULK
• UE_INTERRUPT
• UE_ISOCHRONOUS

Definition at line 270 of file dwc_otg_hcd.h.

uint8_t dwc_otg_qh::dev_speed

Device speed.

One of the following values:

• DWC_OTG_EP_SPEED_LOW
• DWC_OTG_EP_SPEED_FULL
• DWC_OTG_EP_SPEED_HIGH

Definition at line 283 of file dwc_otg_hcd.h.

uint8_t dwc_otg_qh::data_toggle

Determines the PID of the next data packet for non-control transfers.

Ignored for control transfers.
One of the following values:

• DWC_OTG_HC_PID_DATA0
• DWC_OTG_HC_PID_DATA1

Definition at line 292 of file dwc_otg_hcd.h.

uint16_t dwc_otg_qh::sched_frame

(micro)frame to initialize a periodic transfer.

The transfer executes in the following (micro)frame.

Definition at line 321 of file dwc_otg_hcd.h.

uint32_t* dwc_otg_qh::n_bytes

Xfer Bytes array.

Each element corresponds to a descriptor and indicates original XferSize size value for the descriptor.

Definition at line 352 of file dwc_otg_hcd.h.

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The documentation for this struct was generated from the following file:

• dwc_otg_hcd.h

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