STRUCT XUSB_UDC(9)

💅 struct xusb_udc(9)

okay so welcome to the Kernel API Manual, bestie 💖 — this is the page for struct xusb_udc, and it's literally the whole personality of the USB peripheral driver. She's a struct, she's got a spinlock, she's got function pointers, she's booked and busy. Let's get into it 🎀

---

🌸 NAME 🌸

struct xusb_udc — USB peripheral driver structure. that's the vibe. no cap 🫶

---

✨ SYNOPSIS ✨

here's the whole fit, character for character, don't touch a single brace:

struct xusb_udc {
    struct usb_gadget gadget;
    struct xusb_ep ep[8];
    struct usb_gadget_driver *driver;
    struct usb_ctrlrequest setup;
    struct xusb_req *req;
    struct device *dev;
    u32 usb_state;
    u32 remote_wkp;
    u32 setupseqtx;
    u32 setupseqrx;
    void __iomem *addr;
    spinlock_t lock;
    bool dma_enabled;
    struct clk *clk;
    unsigned int (*read_fn)(void __iomem *reg);
    void (*write_fn)(void __iomem *, u32, u32);
 };

she's giving very much "i contain multitudes" 💀

---

🦋 Members 🦋

okay so let's do a member-by-member vibe check, everyone gets their moment 👑

• gadget — the USB gadget driver instance. this is her main character energy, the actual gadget herself ✨
• ep — an array of endpoint structures. yes, an array, the endpoints are matching besties 🫶
• driver — pointer to the usb gadget driver instance. it's a pointer, it points, that's the job 💅
• setup — a usb_ctrlrequest structure for control requests. control requests said "i'll handle it" 🎀
• req — pointer to a dummy request for the get status command. dummy request, real job 🍓
• dev — pointer to the device structure in the gadget. the device, in the gadget, as one does 🦋
• usb_state — tells you whether the device is in a suspended state or not. she keeps receipts 💀
• remote_wkp — remote wakeup enabled by host. host said yes, lowkey 🌸
• setupseqtx — tx status. that's it, that's the member 📤
• setupseqrx — rx status. same energy, incoming 📥
• addr — the usb device base address. like, the address. the base one. iconic 🌈
• lock — an instance of spinlock. spinlock said "i will be spinning" 💫
• dma_enabled — flag indicating whether the dma is included in the system. a bool, a whole yes-or-no moment ⭐
• clk — pointer to struct clk. clock said hi 🕐
• read_fn — function pointer to read device registers. she reads 💖
• write_fn — function pointer to write to device registers. and she writes 💜

ngl the function pointers are the slay of this whole struct — read_fn/write_fn are void __iomem * coded and everything, exactly like the synopsis says, don't come for me 💅

---

🔥 SEE ALSO 🔥

like, the whole friend group lives in the Kernel file ./drivers/usb/gadget/udc/udc-xilinx.c — go say hi to struct xusb_req(9), struct xusb_ep(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).

---

and that's the page, bestie 🧚 — brought to you from ./drivers/usb/gadget/udc, dated October 2026, and honestly the date understood the assignment too 📅💖 mwah, go read some kernel source 🎀