STRUCT D40_PHY_LLI(9)

💅 struct d40_phy_lli(9) — the kernel API manual, but make it make sense

okay so bestie, welcome to the kernel API manual page for struct d40_phy_lli 🎀 this whole thing lives in section 9, and it's the basic configuration register for each physical channel. that's the whole vibe. one struct, four u32s, zero notes app screenshots of it. ✨

---

🌸 NAME 🌸

struct d40_phy_lli — literally the basic configuration register for each physical channel. that's it, that's the icon. 👑

---

✨ SYNOPSIS ✨

here's the whole struct, copied exactly, no notes, no edits, no "i fixed the indentation for you" behaviour (i would never):

struct d40_phy_lli {
    u32 reg_cfg;
    u32 reg_elt;
    u32 reg_ptr;
    u32 reg_lnk;
 };

four fields, all u32, all main character. the way that this fits in a single cache line is lowkey iconic. 💖

---

🦋 Members 🦋

• reg_cfg — the configuration register. yes, the config one. it configures. she's doing her job. 🫶
• reg_elt — the element register. the element girlie. 🌸
• reg_ptr — the pointer register. points at stuff. extremely demure of her. 🎀
• reg_lnk — the link register. the linking one. iykyk. 🔗

---

💜 Description 💜

so here's the tea: these registers are set up for both physical and logical transfers. both modes, same struct, one struct serving looks in two different outfits. 👗✨

but bestie, hear me — note that the bit in each register means differently in logical and physical(standard) mode. like, the same bit position is not saying the same thing depending on which mode you're in. so do NOT read these bits in logical mode with your physical-mode brain on. that's a vibe check failure waiting to happen. 💀

and now the part that actually matters, the critical caveat:

this struct must be 16 bytes aligned, and only contain physical registers, since it will be directly accessed by the DMA.

read that again. 16 bytes aligned. only physical registers. the DMA touches this thing directly, no middleman, no guardrails, no "um actually could you validate that first". it's giving raw hardware energy and we respect her but we also fear her a little. 🔥😭

---

🧚 SEE ALSO 🧚

go read the kernel file, she's right here: ./drivers/dma/ste_dma40_ll.h

and then the whole friend group of related structs, all in the family:

• struct d40_phy_lli_bidir(9)
• struct d40_log_lli(9)
• struct d40_log_lli_bidir(9)
• struct d40_log_lli_full(9)
• struct d40_def_lcsp(9)

that's the group chat, go say hi. 👋💜

---

sign-off time ✨ this absolute baddie of a page comes from ./drivers/dma and is dated October 2026, and it was rendered as struct d40_phy_lli(9) — slay, no cap, periodt. 💅🎀🦋