STRUCT XUSB_EP(9)

💅 struct xusb_ep(9) — bestie, this is the USB end point struct

okay so real talk: this is a page from the Kernel API Manual (the struct xusb_ep(9) one, yes), and it's literally just one struct and all its little members. it's giving "character sheet for a USB endpoint" and honestly? we're obsessed. let's go through it field by field, no cap, nothing skipped 💖

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✨ NAME ✨

struct xusb_ep — the USB end point structure. that's it, that's the whole vibe. periodt.

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🌸 SYNOPSIS 🌸

here's the whole thing, copied exactly, because you know I'm not about to paraphrase a struct definition:

struct xusb_ep {
    struct usb_ep ep_usb;
    struct list_head queue;
    struct xusb_udc *udc;
    const struct usb_endpoint_descriptor *desc;
    u32 rambase;
    u32 offset;
    char name[4];
    u16 epnumber;
    u16 maxpacket;
    u16 buffer0count;
    u16 buffer1count;
    u8 curbufnum;
    bool buffer0ready;
    bool buffer1ready;
    bool is_in;
    bool is_iso;
 };

look at her. sixteen fields. main character energy fr fr 👑

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🦋 Members 🦋

okay this is the part where we meet everyone in the group chat:

• ep_usb — the usb endpoint instance. like, the actual USB-layer self. her public-facing persona ✨
• queue — the endpoint message queue. where the messages line up and wait their turn, patient icons 💅
• udc — a pointer to the xilinx usb peripheral driver instance. so she knows which UDC she belongs to, iykyk
• desc — pointer to the usb endpoint descriptor. her official paperwork 🎀
• rambase — the endpoint buffer address. where her stuff actually lives
• offset — the endpoint register offset value. the little math to find her registers
• name — name of the endpoint. it's a char name[4], so keep it short bestie, four chars and done 🙈
• epnumber — endpoint number. her literal ID number
• maxpacket — maximum packet size the endpoint can store. the biggest parcel she'll accept 📦
• buffer0count — the size of the packet recieved in the first buffer. (yes, the original page spells it "recieved" — I'm keeping it exactly, that's her ✨flavor✨)
• buffer1count — the size of the packet received in the second buffer. buffer two, keeping it consistent 🫶
• curbufnum — current buffer of endpoint that will be processed next. she's literally telling you who's up next 👀
• buffer0ready — the busy state of first buffer. is buffer zero booked or not 💀
• buffer1ready — the busy state of second buffer. same question, second buffer
• is_in — endpoint direction (IN or OUT). which way the data's going, no ambiguity 🌈
• is_iso — endpoint type (isochronous or non isochronous). is she iso or is she not, that's the question ⭐

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🔥 SEE ALSO 🔥

go read these next, bestie — the whole xilinx USB gadget gang is here, and yes I'm listing every single one because we don't do "etc." in this house:

Kernel file ./drivers/usb/gadget/udc/udc-xilinx.c, plus struct xusb_req(9), struct xusb_udc(9), xudc_write32(9), xudc_read32(9), xudc_write32_be(9), xudc_read32_be(9), xudc_wrstatus(9), xudc_epconfig(9), xudc_start_dma(9), xudc_dma_send(9), xudc_dma_receive(9), xudc_eptxrx(9), xudc_done(9), xudc_read_fifo(9), xudc_write_fifo(9), xudc_nuke(9), xudc_ep_set_halt(9), __xudc_ep_enable(9), xudc_ep_enable(9), xudc_ep_disable(9), xudc_ep_alloc_request(9), xudc_free_request(9), __xudc_ep0_queue(9), xudc_ep0_queue(9), xudc_ep_queue(9), xudc_ep_dequeue(9), xudc_ep0_enable(9), xudc_ep0_disable(9), xudc_get_frame(9), xudc_wakeup(9), xudc_pullup(9), xudc_eps_init(9), xudc_stop_activity(9), xudc_start(9), xudc_stop(9), xudc_clear_stall_all_ep(9), xudc_startup_handler(9), xudc_ep0_stall(9), xudc_setaddress(9), xudc_getstatus(9), xudc_set_clear_feature(9), xudc_handle_setup(9), xudc_ep0_out(9), xudc_ep0_in(9), xudc_ctrl_ep_handler(9), xudc_nonctrl_ep_handler(9), xudc_irq(9), xudc_probe(9), xudc_remove(9).

that's a lot of cross-references and I typed every one of them. you're welcome. 💖

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and that's the page!! written by the gang over in ./drivers/usb/gadget/udc, dated October 2026 — mwah, luv u, go read xudc_probe(9) next 🧚‍♀️