pcim_iomap(9)

💅 pcim_iomap(9) — like, the managed iomap one

okay bestie, welcome to the Kernel API Manual entry for pcim_iomap, aka the function that maps a PCI BAR for you and then quietly cleans up after itself like the responsible main character it is 🎀

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✨ NAME ✨

pcim_iomap — the managed version of pcim_iomap(), no cap 💖

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🦋 SYNOPSIS 🦋

void __iomem * pcim_iomap (struct pci_dev *pdev , int bar , unsigned
       long maxlen );

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🌸 ARGUMENTS 🌸

• pdev — the PCI device you're iomapping for, your little guy 🫶
• bar — which BAR you wanna iomap, pick one bestie
• maxlen — the maximum length of the iomap, aka how much you're asking for

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⭐ RETURN ⭐

you get a __iomem pointer on success, and NULL on failure. that's it, that's the deal ✨

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💜 DESCRIPTION 💜

so this is the managed pci_iomap. the map gets automatically unmapped on driver detach — the kernel handles the cleanup for you, obsessed 😭

but like, if you really want to unmap it manually? you can, but only with pcim_iounmap. literally only that one, iykyk 💅

also this SHOULD only be used once per BAR. once. per BAR. don't be weird about it 🙈

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🎀 NOTE 🎀

okay this is important so listen up 🔥 contrary to all the other pcim_* functions, this one does NOT return an IOMEM_ERR_PTR on failure — it returns a simple NULL instead. and why? for backwards compatibility, bestie. that's the whole reason. periodt 💀

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🌈 SEE ALSO 🌈

kernel file ./drivers/pci/devres.c plus all these iconic neighbors:

devm_pci_remap_iospace(9), devm_pci_remap_cfgspace(9), devm_pci_remap_cfg_resource(9), pcim_set_mwi(9), pcim_intx(9), pcim_enable_device(9), pcim_pin_device(9), pcim_iomap_table(9), pcim_iounmap(9), pcim_iomap_region(9), pcim_iounmap_region(9), pcim_iomap_regions(9), pcim_request_region(9), pcim_release_region(9), pcim_release_all_regions(9), pcim_request_all_regions(9), pcim_iomap_range(9) 🦋

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and that's the whole page, bestie! this one lives in ./drivers/pci and it's dated October 2026 — go forth and map responsibly, mwah 💋👑