drivers/pci/mmap.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Generic PCI resource mmap helper
 *
 * Copyright © 2017 Amazon.com, Inc. or its affiliates.
 *
 * Author: David Woodhouse <dwmw2@infradead.org>
 */

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/pci.h>

#include "pci.h"

#ifdef ARCH_GENERIC_PCI_MMAP_RESOURCE

static const struct vm_operations_struct pci_phys_vm_ops = {
#ifdef CONFIG_HAVE_IOREMAP_PROT
	.access = generic_access_phys,
#endif
};

int pci_mmap_resource_range(struct pci_dev *pdev, int bar,
			    struct vm_area_struct *vma,
			    enum pci_mmap_state mmap_state, int write_combine)
{
	unsigned long size;
	int ret;

	size = ((pci_resource_len(pdev, bar) - 1) >> PAGE_SHIFT) + 1;
	if (vma->vm_pgoff + vma_pages(vma) > size)
		return -EINVAL;

	if (write_combine)
		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
	else
		vma->vm_page_prot = pgprot_device(vma->vm_page_prot);

	if (mmap_state == pci_mmap_io) {
		ret = pci_iobar_pfn(pdev, bar, vma);
		if (ret)
			return ret;
	} else
		vma->vm_pgoff += (pci_resource_start(pdev, bar) >> PAGE_SHIFT);

	vma->vm_ops = &pci_phys_vm_ops;

	return io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
				  vma->vm_end - vma->vm_start,
				  vma->vm_page_prot);
}

#endif

#if (defined(CONFIG_SYSFS) || defined(CONFIG_PROC_FS)) && \
    (defined(HAVE_PCI_MMAP) || defined(ARCH_GENERIC_PCI_MMAP_RESOURCE))

int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vma,
		  enum pci_mmap_api mmap_api)
{
	resource_size_t pci_start = 0, pci_end;
	unsigned long nr, start, size;

	if (pci_resource_len(pdev, resno) == 0)
		return 0;
	nr = vma_pages(vma);
	start = vma->vm_pgoff;
	size = ((pci_resource_len(pdev, resno) - 1) >> PAGE_SHIFT) + 1;
	if (mmap_api == PCI_MMAP_PROCFS) {
		pci_resource_to_user(pdev, resno, &pdev->resource[resno],
				     &pci_start, &pci_end);
		pci_start >>= PAGE_SHIFT;
	}
	if (start >= pci_start && start < pci_start + size &&
	    start + nr <= pci_start + size)
		return 1;
	return 0;
}

#endif