STRUCT PCI_EPF_BAR_SUBMAP(9)

✨ struct pci_epf_bar_submap — BAR subrange for inbound mapping ✨

okay bestie so this is a page straight out of the Kernel API Manual (yep, that's the manual name, we're fancy now 💅) and it's all about struct pci_epf_bar_submap. it's giving "small struct, big job" honestly.

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🎀 SYNOPSIS 🎀

struct pci_epf_bar_submap {
    dma_addr_t phys_addr;
    size_t size;
 };

like… two fields. two. and yet she's iconic. look at her 🫶

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🌸 Members 🌸

• phys_addr — the target physical/DMA address for this subrange. this is where the thing actually lives, no cap.
• size — the size of the subrange that's gonna get mapped. how much of the vibe are we covering ✨

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💖 Description 💖

so here's the tea, bestie ☕ when pci_epf_bar.num_submap is > 0, then pci_epf_bar.submap describes the complete BAR layout. literally the whole picture.

this lets an EPC driver program multiple inbound translation windows for a single BAR — but only when the controller supports it, iykyk. so if your controller's not about that life, this is a no-go 🙈

and the array order? that defines the BAR layout. so submap[0] sits at offset 0, and every one after it immediately follows the previous one. in order. no skipping. main character energy only 👑

⚠️ lowkey important: the ordering isn't decorative — it is the layout. don't go shuffling the array and expecting good things 💀

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🦋 SEE ALSO 🦋

• Kernel file ./include/linux/pci-epf.h
• struct pci_epf_header(9)
• struct pci_epf_ops(9)
• struct pci_epc_event_ops(9)
• struct pci_epf_driver(9)
• struct pci_epf_bar(9)
• struct pci_epf_doorbell_msg(9)
• struct pci_epf(9)
• struct pci_epf_msix_tbl(9)

like, the whole friend group fr fr 🌈 go read them, you'll get it 💜

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that's the whole page babes ✨ this one lives over in ./include/linux in the Kernel API Manual, dated October 2026 — so bestie, struct pci_epf_bar_submap(9) is stamped, sealed, and slaying 🎀💫 periodt.