STRUCT CDMAC_BD(9)

okay so bestie, welcome to the struct cdmac_bd(9) page from the Kernel API Manual ✨ this one is all about the LocalLink buffer descriptor format, and it's giving tiny-but-important kernel struct energy 💅

💖 NAME 💖

struct cdmac_bd — LocalLink buffer descriptor format 🦋

✨ SYNOPSIS ✨

       struct cdmac_bd {
           u32 next;
           u32 phys;
           u32 len;
           u32 app0;
           u32 app1;
           u32 app2;
           u32 app3;
           u32 app4;
        };

🎀 Members 🎀

The members are exactly the fields in the struct above — next, phys, len, and the whole app0 through app4 squad. No cap. 💖

💅 Description 💅

Okay so the app0 bits are the main character here, and here's the full breakdown, bestie:

• 0 — Error
• 1 — IrqOnEnd — generate an interrupt at completion of DMA op
• 2 — reserved
• 3 — completed — Current descriptor completed
• 4 — SOP — TX - marks first desc/ RX marks first desct
• 5 — EOP — TX marks last desc/RX marks last desc
• 6 — EngBusy — DMA is processing
• 7 — reserved
• 8:31 — application specific

that desct in bit 4 is literally what the page says, so we're keeping it exactly like that 💀

🦋 SEE ALSO 🦋

Wanna go deeper? Peek at the kernel file ./drivers/net/ethernet/xilinx/ll_temac.h 👀

mwah 💋 this page is from the ./drivers/net/ethernet/xilinx source/version, dated October 2026, and it's all about struct cdmac_bd(9) — byeee 🫶