pci_iomap_range(9)

📦 version 7.3.1, in nixpkgs unstable

🌸 NAME 🌸

Okay so this page is pci_iomap_range, and it lives in the Kernel API Manual. Its whole thing? Creating a virtual mapping cookie for a PCI BAR. Iconic behavior, honestly. 💅

✨ SYNOPSIS ✨

void __iomem * pci_iomap_range (struct pci_dev *dev , int bar , unsigned long offset , unsigned long maxlen );

🎀 ARGUMENTS 🎀

  • dev — the PCI device that owns the BAR. Like, whose BAR is this? This one. 🫶
  • bar — the BAR number. Just the number, bestie.
  • offset — map memory at the given offset in the BAR. So you're not starting at the very beginning unless you say so.
  • maxlen — max length of the memory to map. The limit, the cap, the "don't get carried away" number. ✨

💖 DESCRIPTION 💖

Using this function, you get a __iomem address to your device BAR. That's the prize. 🎁

You can access it using ioread*() and iowrite*(). These functions hide the details if this is a MMIO or PIO address space, and they will just do what you expect from them in the correct way. No cap, they really do handle the vibe check for you. 🔥

maxlen specifies the maximum length to map. If you want to get access to the complete BAR from offset to the end, pass 0 here. That's the little shortcut, iykyk. 👑

🦋 SEE ALSO 🦋

Kernel file ./drivers/pci/iomap.c:

💜 That's the page, bestie. Cute little footer crumbs: source/version is ./drivers/pci, dated October 2026, and it's all about pci_iomap_range(9). Slay. 🎀
📦 where this page comes from