xdma_prep_device_sg(9)

💅 xdma_prep_device_sg(9) — from the Kernel API Manual, bestie 🫶

✨ NAME ✨

xdma_prep_device_sg — okay so this is the one that prepares a descriptor for a DMA transaction. That's the whole vibe. It sets the descriptor up. It does not send it. We're prepping, not performing. 💅

---

🎀 SYNOPSIS 🎀

struct dma_async_tx_descriptor * xdma_prep_device_sg (struct dma_chan
*chan , struct scatterlist *sgl , unsigned int sg_len , enum
dma_transfer_direction dir , unsigned long flags , void *context );

Like, look at her. Six arguments, one return value, zero notes. She's booked and busy. ⭐

---

🌸 ARGUMENTS 🌸

• chan — DMA channel pointer. Your channel. The main character of this whole operation, honestly. 👑
• sgl — Transfer scatter gather list. This is your list. It's scattered. It's gathered. It's giving range. 🌈
• sg_len — Length of scatter gather list. Yes bestie, the list has a length, pls pass it correctly. 😭
• dir — Transfer direction. Which way are the bytes going? That's it. That's the whole argument. 🔥
• flags — transfer ack flags. The ack flags. For the transfer. Ngl the lowercase in the original is sending me but we keep it exactly as written. 💀
• context — APP words of the descriptor. The APP words!! Of the descriptor!! They go in the context slot!! 🦋

---

👀 SEE ALSO

The kernel file in question is ./drivers/dma/xilinx/xdma.c. That's the home base, the lore drop, the source of truth. 💖

Then there's a whole friend group of structs — go say hi to all of them:

• struct xdma_desc_block(9)
• struct xdma_chan(9)
• struct xdma_desc(9)
• struct xdma_device(9)

And then the entire extended friend circle, no cap, we're listing all of them because nobody gets left behind in this group chat:

• xdma_link_sg_desc_blocks(9)
• xdma_link_cyclic_desc_blocks(9)
• xdma_channel_init(9)
• xdma_free_desc(9)
• xdma_alloc_desc(9)
• xdma_xfer_start(9)
• xdma_xfer_stop(9)
• xdma_alloc_channels(9)
• xdma_issue_pending(9)
• xdma_terminate_all(9)
• xdma_synchronize(9)
• xdma_fill_descs(9)
• xdma_prep_dma_cyclic(9)
• xdma_prep_interleaved_dma(9)
• xdma_device_config(9)
• xdma_free_chan_resources(9)
• xdma_alloc_chan_resources(9)
• xdma_channel_isr(9)
• xdma_irq_fini(9)
• xdma_set_vector_reg(9)
• xdma_irq_init(9)
• xdma_disable_user_irq(9)
• xdma_enable_user_irq(9)
• xdma_get_user_irq(9)
• xdma_remove(9)
• xdma_probe(9)

Thirty entries. I counted. We're thorough in this house. 🧚

Real talk though — this page is genuinely just the prep step, so if you're wondering what happens after you prep a descriptor, that's not on this page. Go read the rest of the friend group above. iykyk 🎀

---

<div align="center">✨ so that's the whole page ✨</div>

And that's a wrap, bestie! This lil' slice of the Kernel API Manual lives over in ./drivers/dma/xilinx and the version vibe is dated October 2026 — so it's giving futuristic but also somehow already nostalgic. Periodt. 💅🫶🌸