STRUCT DWC2_HSOTG_EP(9)

💖 NAME 💖

okay so bestie, welcome to the struct dwc2_hsotg_ep(9) page from the Kernel API Manual ✨ this whole thing is the driver endpoint definition, and we're gonna walk through every single member like it's a group-chat recap. no skipping, no cap 💅

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✨ SYNOPSIS ✨

here's the struct in all its iconic glory, copied exactly — she's sensitive about formatting, so don't touch:

       struct dwc2_hsotg_ep {
           struct usb_ep           ep;
           struct list_head        queue;
           struct dwc2_hsotg       *parent;
           struct dwc2_hsotg_req    *req;
           struct dentry           *debugfs;
           unsigned long           total_data;
           unsigned int            size_loaded;
           unsigned int            last_load;
           unsigned int            fifo_load;
           unsigned short          fifo_size;
           unsigned short          fifo_index;
           unsigned char           dir_in;
           unsigned char           map_dir;
           unsigned char           index;
           unsigned char           mc;
           u16 interval;
           unsigned int            halted:1;
           unsigned int            periodic:1;
           unsigned int            isochronous:1;
           unsigned int            send_zlp:1;
           unsigned int            wedged:1;
           unsigned int            target_frame;
         #define TARGET_FRAME_INITIAL   0xFFFFFFFF;
           bool frame_overrun;
           dma_addr_t desc_list_dma;
           struct dwc2_dma_desc    *desc_list;
           u8 desc_count;
           unsigned int            next_desc;
           unsigned int            compl_desc;
           char name[10];
        };

literally every field is right there. periodt 🫶

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🧚 Members 🧚

• ep — the gadget-layer representation of the endpoint. main character energy.
• queue — the queue of requests for this endpoint. it's giving "line starts here" 💅
• parent — a reference back to the parent device structure. gotta know where you came from.
• req — the current request that the endpoint is processing. this is used to indicate a request has been loaded onto the endpoint and has yet to be completed — maybe because data still needs to move, or simply because we're awaiting an ack from the core that all the data has been completed. lowkey suspenseful 😭
• debugfs — the file entry for the debugfs file for this endpoint. debug girlie representation ✨
• total_data — the total number of data bytes done. she's counting.
• size_loaded — the last loaded size for DxEPTSIZE for periodic IN.
• last_load — the offset of data for the last start of request.
• fifo_load — the amount of data loaded into the FIFO (periodic IN).
• fifo_size — the size of the FIFO (for periodic IN endpoints).
• fifo_index — for Dedicated FIFO operation, only FIFO0 can be used for EP0. noted.
• dir_in — set to true if this endpoint is of the IN direction, which means it is sending data to the Host.
• map_dir — set to the value of dir_in when the DMA buffer is mapped.
• index — the index for the endpoint registers.
• mc — Multi Count — number of transactions per microframe.
• interval — interval for periodic endpoints, in frames or microframes.
• halted — set if the endpoint has been halted. 🛑
• periodic — set if this is a periodic ep, such as Interrupt.
• isochronous — set if this is a isochronous ep.
• send_zlp — set if we need to send a zero-length packet. tiny but powerful.
• wedged — set if ep is wedged. oh no 💀
• target_frame — targeted frame num to setup next ISOC transfer. also, the struct carries #define TARGET_FRAME_INITIAL 0xFFFFFFFF; right there in the synopsis, iconic.
• frame_overrun — indicates SOF number overrun in DSTS.
• desc_list_dma — the DMA address of descriptor chain currently in use.
• desc_list — pointer to descriptor DMA chain head currently in use.
• desc_count — count of entries within the DMA descriptor chain of EP.
• next_desc — index of next free descriptor in the ISOC chain under SW control.
• compl_desc — index of next descriptor to be completed by xFerComplete.
• name — the name array passed to the USB core. char name[10], bestie — ten characters of pure identity 💖

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🌸 Description 🌸

so this is the driver's state for each registered endpoint, allowing it to keep track of transactions that need doing. each endpoint has a lock to protect the state, to try and avoid using an overall lock for the host controller as much as possible. slay for not making everything one giant lock, honestly 👑

for periodic IN endpoints, we have fifo_size and fifo_load to try and keep track of the amount of data in the periodic FIFO for each of these — because we don't have a status register that tells us how much is in each of them. 😭 and yes, the original note says this may actually be useless information, as in shared-fifo mode periodic IN acts like a single-frame packet buffer than a fifo. we respect the source's exact vibe.

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💅 SEE ALSO 💅

• Kernel file ./drivers/usb/dwc2/core.h
• struct dwc2_hsotg_req(9)
• struct dwc2_core_params(9)
• struct dwc2_hw_params(9)
• struct dwc2_gregs_backup(9)
• struct dwc2_dregs_backup(9)
• struct dwc2_hregs_backup(9)
• struct dwc2_hsotg(9)

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mwah 💋 this page lives at ./drivers/usb/dwc2, dated October 2026, and it's all about struct dwc2_hsotg_ep(9) — bye bestie, go read some endpoint registers for me 🫶✨