iudma_read(9)

🌸 iudma_read — the Kernel API Manual page, bestie edition 🌸

okay so this is a page from the Kernel API Manual (iudma_read(9), section 9, the whole vibe) and honestly? it's short, it's sweet, it's giving "small function, big feelings" ✨ let's get into it 🫶

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✨ NAME ✨

iudma_read — check for IUDMA buffer completion 💖 like, is the DMA channel done yet or not, that's the whole assignment

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🦋 SYNOPSIS 🦋

int iudma_read (struct bcm63xx_udc *udc , struct iudma_ch *iudma );

that's it. that's the signature. she's small and she returns an int 💅

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🎀 ARGUMENTS 🎀

• udc — your reference to the device controller 👑 this is the big boss object, the one that owns everything else
• iudma — the IUDMA channel you're working with 🦋 the specific lane we're checking on, iykyk

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⭐ DESCRIPTION ⭐

so here's the tea ☕ this function checks whether ALL of the outstanding BDs on the DMA channel have been filled 👀 like, every single one, no halfsies, no "ehh close enough"

if they have? slay 💅 it returns the actual transfer length 🔥 the real number, the good number

if they haven't? it returns -EBUSY 😭 which is the kernel's way of saying "girl not yet, come back later"

lowkey important: it's ALL of them or nothing, fr fr — partial completion does not get you a length, it gets you -EBUSY 💀

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💜 SEE ALSO 💜

okay this is the part where the whole friend group shows up 🌈 first, the file she lives in:

Kernel file ./drivers/usb/gadget/udc/bcm63xx_udc.c

and now the full crew, every single one, no cap 🫶

• struct iudma_ch_cfg(9)
• struct iudma_ch(9)
• struct bcm63xx_ep(9)
• struct bcm63xx_req(9)
• struct bcm63xx_udc(9)
• bcm63xx_ep_dma_select(9)
• bcm63xx_set_stall(9)
• bcm63xx_fifo_setup(9)
• bcm63xx_fifo_reset_ep(9)
• bcm63xx_fifo_reset(9)
• bcm63xx_ep_init(9)
• bcm63xx_ep_setup(9)
• iudma_write(9)
• iudma_reset_channel(9)
• iudma_init_channel(9)
• iudma_init(9)
• iudma_uninit(9)
• bcm63xx_set_ctrl_irqs(9)
• bcm63xx_select_phy_mode(9)
• bcm63xx_select_pullup(9)
• bcm63xx_uninit_udc_hw(9)
• bcm63xx_init_udc_hw(9)
• bcm63xx_ep_enable(9)
• bcm63xx_ep_disable(9)
• bcm63xx_udc_alloc_request(9)
• bcm63xx_udc_free_request(9)
• bcm63xx_udc_queue(9)
• bcm63xx_udc_dequeue(9)
• bcm63xx_udc_set_halt(9)
• bcm63xx_udc_set_wedge(9)
• bcm63xx_ep0_setup_callback(9)
• bcm63xx_ep0_spoof_set_cfg(9)
• bcm63xx_ep0_spoof_set_iface(9)
• bcm63xx_ep0_map_write(9)
• bcm63xx_ep0_complete(9)
• bcm63xx_ep0_nuke_reply(9)
• bcm63xx_ep0_read_complete(9)
• bcm63xx_ep0_internal_request(9)
• bcm63xx_ep0_do_setup(9)
• bcm63xx_ep0_do_idle(9)
• bcm63xx_ep0_one_round(9)
• bcm63xx_ep0_process(9)
• bcm63xx_udc_get_frame(9)
• bcm63xx_udc_pullup(9)
• bcm63xx_udc_start(9)
• bcm63xx_udc_stop(9)
• bcm63xx_update_cfg_iface(9)
• bcm63xx_update_link_speed(9)
• bcm63xx_update_wedge(9)
• bcm63xx_udc_ctrl_isr(9)
• bcm63xx_udc_data_isr(9)
• bcm63xx_udc_init_debugfs(9)
• bcm63xx_udc_cleanup_debugfs(9)
• bcm63xx_udc_probe(9)
• bcm63xx_udc_remove(9)

like I said. the whole group chat 💀💖

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that's the page!! short king behavior honestly 👑 this little cutie comes to you from ./drivers/usb/gadget/udc, dated October 2026, and it's filed under iudma_read(9) — go read the others too bestie, they're all in the SEE ALSO, mwah 😘💅✨