xudc_dma_receive(9)

💅 xudc_dma_receive(9) — the Kernel API Manual tea ☕✨

okay so bestie, welcome to the Kernel API Manual entry for xudc_dma_receive(9) — yes the whole manual is literally named "Kernel API Manual" and this one page is your new hyperfixation. let's get into it 🫶

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✨ NAME ✨

xudc_dma_receive — receives OUT data using DMA. that's it, that's the vibe. it pulls data in, DMA does the heavy lifting, we stan a low-effort queen 💅

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🌸 SYNOPSIS 🌸

int xudc_dma_receive (struct xusb_ep *ep , struct xusb_req *req , u8
*buffer , u32 length );

yes the line break in the middle is real, it's giving "wrapped because terminal said no" 😭 copy it exactly, don't @ me.

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🎀 ARGUMENTS 🎀

• ep — pointer to the usb device endpoint structure. like, the endpoint's whole personality lives here 🔥
• req — pointer to the usb request structure. the request in question, the main character of this transaction 👑
• buffer — pointer to storage buffer of received data. this is where the data actually lands, the cute little landing pad 🦋
• length — number of bytes to receive. how many bytes we're pulling in, fr fr — count them, bestie 🍓

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⭐ RETURN ⭐

• 0 on success — slay, we ate 💖
• -EAGAIN if no buffer is free — literally the "try again later babe" of error codes 😭
• an error code on failure — when things go sideways, it tells you with a code, no guessing 🙈

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🌈 DESCRIPTION 🌈

this function receives data using DMA. that's the whole thing — it takes the data-in path and lets DMA handle the transfer instead of making the CPU do it by hand. iconic behaviour, no notes ✨

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🧚 SEE ALSO 🧚

first up, the source file itself: Kernel file ./drivers/usb/gadget/udc/udc-xilinx.c — go read her, she's the blueprint 📖

and literally all her friends (in order, because we're respectful like that):

• struct xusb_req(9), struct xusb_ep(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_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)

bestie that's the whole friend group, no cap. every single one of them is a (9) manpage and every single one is invited to the group chat 💀💖

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and that's the page!! mwah 💋 this lil entry lives over in ./drivers/usb/gadget/udc and it's dated October 2026 — so yeah, mark your calendar, screenshot it, put it on the fridge 🎀✨ xoxo, your kernel bestie 🦋