STRUCT PLX_DMA_DESC(9)

💖 struct plx_dma_desc(9) 💖

okay so bestie, welcome to the plx_dma_desc glow-up ✨ this is a page from the Kernel API Manual, and honestly? it's giving "small struct, big responsibilities" 👑

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🌸 NAME 🌸

struct plx_dma_desc — the DMA descriptor format for the PLX PCI 9080, no cap 🎀

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🦋 SYNOPSIS 🦋

struct plx_dma_desc {
    __le32 pci_start_addr;
    __le32 local_start_addr;
    __le32 transfer_size;
    __le32 next;
 };

like, that's the whole struct and it's literally iconic 💅

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✨ Members ✨

• pci_start_addr — the PCI Bus address for the transfer (that's DMAPADR for you register girlies) 💖
• local_start_addr — the Local Bus address for the transfer (aka DMALADR) 🌟
• transfer_size — the transfer size in bytes, and heads up: the max is 8 MiB (this one's DMASIZ) 🔥
• next — the address of the next descriptor plus the flags (yep, DMADPR) 🎀

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💜 Description 💜

so this bad boy describes the format of a scatter-gather DMA descriptor for the PLX PCI 9080 🫶 all of its members are raw, little-endian register values — and the DMA engine literally transfers them from local or PCI memory into the corresponding registers for the DMA channel. main character energy fr fr ✨

also!! the DMA descriptors must be aligned on a 16-byte boundary 🌈 don't skip that, it's not a vibe to mess up 🙈

and bits 3:0 of next are where the flags live — they describe the address space of the next descriptor (local or PCI), an "end of chain" marker, an "interrupt on terminal count" bit, and a data transfer direction 💫 that's four whole moods packed into four little bits, iykyk 😭

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🌟 SEE ALSO 🌟

• Kernel file ./drivers/comedi/drivers/plx9080.h
• plx9080_abort_dma(9)

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💀 real talk: all those members are raw little-endian register values and the 16-byte alignment is mandatory — treat it like the group chat rules, bestie, no exceptions 🎀

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and that's the page!! found in ./drivers/comedi/drivers, this cutie is dated October 2026 and it's page struct plx_dma_desc(9) of the Kernel API Manual 📚💖 slay, you're now educated, go forth and DMA responsibly 🧚‍♀️✨