STRUCT PXAD_PARAM(9)

🎀 struct pxad_param(9) 🎀

okay bestie, welcome to the Kernel API Manual (section 9, very official, very demure) — today we're learning about struct pxad_param, which is literally just the little info packet you hand over when you want a DMA channel. it's giving "application form but for hardware" 💅

---

✨ NAME ✨

struct pxad_param — dma channel request parameters 🦋

like, the parameters. for requesting a dma channel. that's the whole vibe. no cap.

---

🌸 SYNOPSIS 🌸

here's the whole struct, bestie, and yes it's tiny — don't let the tinyness fool you, she's iconic:

struct pxad_param {
    unsigned int drcmr;
    enum pxad_chan_prio prio;
 };

⚠️ real talk: copy this exactly if you're using it. character for character. no "fixing" the indentation, no renaming fields, none of that 🙈

---

💖 Members 💖

two fields. two. and honestly? both matter. let's go:

• drcmr — the requestor line number 🧚 this is the number that says "hey, this is the line asking for the channel." that's it, that's the field.
• prio — the minimal mandatory priority of the channel 👑 key word: mandatory. this isn't a suggestion, this is a requirement, periodt.

---

🔥 Description 🔥

okay so here's the actual tea ☕ — if a requested channel is granted, its priority will be at least prio.

"at least" is doing so much work in that sentence, so let's spell it out the way the page does: if PXAD_PRIO_LOW is required, the requested channel will be either PXAD_PRIO_LOW, PXAD_PRIO_NORMAL or PXAD_PRIO_HIGHEST ✨

like, you're asking for a floor, not a ceiling. you say low, you might get low, you might get normal, you might get highest — but you will never get anything below what you asked for. main character energy fr fr 💅

---

🫶 SEE ALSO 🫶

Kernel file ./include/linux/dma/pxa-dma.h — go read it, iykyk 📖

---

and that's the page!! mwah 💋 this one came from ./include/linux/dma and it's dated October 2026, so jot that down in your notes bestie 🗓️⭐ slay, you now understand struct pxad_param. go request some channels responsibly 🦋💜