pci_iomap_wc_range(9)

🌸 pci_iomap_wc_range(9) — Kernel API Manual 🌸

okay so bestie, welcome to the pci_iomap_wc_range(9) page. This is the Kernel API Manual, and we're about to get a virtual WC mapping cookie for a PCI BAR. It's giving low-level PCI, but make it cute. 💅

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💖 NAME 💖

pci_iomap_wc_range — create a virtual WC mapping cookie for a PCI BAR. That's the whole name vibe, periodt. ✨

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🎀 SYNOPSIS 🎀

the signature is literally this, character for character:

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

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🦋 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 BAR. That's the spot. ✨
• maxlen — max length of the memory to map. The limit, the ceiling, the cap. 👑

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💜 DESCRIPTION 💜

Using this function gets you a __iomem address to your device BAR. That's the whole point. 🎯 You can access it using ioread*() and iowrite*(). These functions hide the details if this is a MMIO or PIO address space and will just do what you expect from them in the correct way. They're the main characters of access here, no cap. 🫶 When possible write combining is used. Slay. ✨

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 shortcut, bestie — zero means the whole stretch from offset onward. 🔥

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🌈 SEE ALSO 🌈

Go peek at the kernel file ./drivers/pci/iomap.c — and also pci_iomap_range(9), pci_iomap(9), and pci_iomap_wc(9). iykyk. 💖

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mwah 💋 — sourced from ./drivers/pci, dated October 2026, page pci_iomap_wc_range(9), and that's the footer vibe, periodt. 🫶