pio_copy(9)

💖 pio_copy(9) — the Kernel API Manual page, bestie edition 💖

okay so this is pio_copy from the Kernel API Manual, and honestly? she's a little workhorse and we're gonna stan her properly.

---

✨ NAME ✨

pio_copy — copy data block to MMIO space 💅

---

🦋 SYNOPSIS 🦋

void pio_copy (struct hfi1_devdata *dd , struct pio_buf *pbuf , u64 pbc
, const void *from , size_t count );

---

🎀 ARGUMENTS 🎀

• dd — the hfi1 dev data, aka the main character's ID 💖
• pbuf — a number of blocks allocated within a PIO send context, slay
• pbc — the PBC to send, no cap
• from — the source, and it MUST be 8 byte aligned — like, non-negotiable, bestie 🫶
• count — number of DWORD (32-bit) quantities to copy from source, fr fr

---

🌸 DESCRIPTION 🌸

Copy data from source to PIO Send Buffer memory, 8 bytes at a time. That's the whole vibe 💫

You must always write full BLOCK_SIZE bytes blocks — not a byte less, not being cute about it, full blocks only 🙈

The first block must be written to the corresponding SOP=1 address. Like, that's where she starts, periodt 👑

Known things (iykyk):

• pbuf->start always starts on a block boundary
• pbuf can wrap only at a block boundary

---

💜 SEE ALSO 💜

Kernel file ./drivers/infiniband/hw/hfi1/pio_copy.c — go read her, she's iconic 🧚

---

ok that's the whole page and yes she's short but she's perfect 💀✨

---

and that's a wrap, bestie!! this one's from the ./drivers/infiniband/hw/hfi1 directory, dated October 2026 — screenshot it, cite it, live laugh love it 💖🎀🦋⭐🌈👑