rio_dma_prep_xfer(9)

📦 version 7.3.1, in nixpkgs unstable

rio_dma_prep_xfer(9) from the Kernel API Manual — bestie, we're doing RapidIO DMA setup and it's giving “small function, big callback energy” 💅✨

💖 NAME 💖

rio_dma_prep_xfer — the RapidIO specific wrapper for the device_prep_slave_sg callback defined by DMAENGINE. no cap, that's literally the whole name vibe 🫶

🦋 SYNOPSIS 🦋

struct dma_async_tx_descriptor * rio_dma_prep_xfer (struct dma_chan
       *dchan , u16 destid , struct rio_dma_data *data , enum
       dma_transfer_direction direction , unsigned long flags );

🎀 ARGUMENTS 🎀

okay so here's the cast of characters, and yes every one matters:

  • dchan — the DMA channel to configure. main character channel energy ✨
  • destid — target RapidIO device destination ID. like the address of the bestie you're sending to 💌
  • data — RIO specific data descriptor. the whole lil data package 🎁
  • direction — DMA data transfer direction (TO or FROM the device). pick a lane, bestie 🔁
  • flags — dmaengine defined flags. the little switches and knobs 🎛️

✨ DESCRIPTION ✨

So this function initializes a RapidIO capable DMA channel for the specified data transfer. It uses the DMA channel private extension to pass information related to the remote target RIO device. That's it, that's the tea ☕💅

💖 RETURN 💖

Returns a pointer to DMA transaction descriptor if successful. If it fails, you get an error-valued pointer or NULL. so: success = descriptor pointer, failure = error-valued pointer or NULL, pls check before you celebrate 😭✨

🌈 SEE ALSO 🌈

Kernel file: ./drivers/rapidio/rio.c

The whole RapidIO friend group, all invited to the group chat:

💌 sign-off: source/version is ./drivers/rapidio, date is October 2026. bye bestie, go prep that xfer 🫶💅

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