WSL2-Linux-Kernel/lib/pci_iomap.c

/*
 * Implement the default iomap interfaces
 *
 * (C) Copyright 2004 Linus Torvalds
 */
#include <linux/pci.h>
#include <linux/io.h>

#include <linux/export.h>

#ifdef CONFIG_PCI
/**
 * pci_iomap - create a virtual mapping cookie for a PCI BAR
 * @dev: PCI device that owns the BAR
 * @bar: BAR number
 * @maxlen: length of the memory to map
 *
 * Using this function you will get a __iomem address to your device BAR.
 * 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.
 *
 * @maxlen specifies the maximum length to map. If you want to get access to
 * the complete BAR without checking for its length first, pass %0 here.
 * */
void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
{
	resource_size_t start = pci_resource_start(dev, bar);
	resource_size_t len = pci_resource_len(dev, bar);
	unsigned long flags = pci_resource_flags(dev, bar);

	if (!len || !start)
		return NULL;
	if (maxlen && len > maxlen)
		len = maxlen;
	if (flags & IORESOURCE_IO)
		return __pci_ioport_map(dev, start, len);
	if (flags & IORESOURCE_MEM) {
		if (flags & IORESOURCE_CACHEABLE)
			return ioremap(start, len);
		return ioremap_nocache(start, len);
	}
	/* What? */
	return NULL;
}

EXPORT_SYMBOL(pci_iomap);
#endif /* CONFIG_PCI */