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/*
* mmap.c — generic PCI resource mmap helper
*
* Copyright © 2017 Amazon.com, Inc. or its affiliates.
*
* Author: David Woodhouse <dwmw2@infradead.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/pci.h>
#ifdef ARCH_GENERIC_PCI_MMAP_RESOURCE
/*
* Modern setup: generic pci_mmap_resource_range(), and implement the legacy
* pci_mmap_page_range() (if needed) as a wrapper round it.
*/
#ifdef HAVE_PCI_MMAP
int pci_mmap_page_range(struct pci_dev *pdev, int bar,
struct vm_area_struct *vma,
enum pci_mmap_state mmap_state, int write_combine)
{
resource_size_t start, end;
pci_resource_to_user(pdev, bar, &pdev->resource[bar], &start, &end);
/* Adjust vm_pgoff to be the offset within the resource */
vma->vm_pgoff -= start >> PAGE_SHIFT;
return pci_mmap_resource_range(pdev, bar, vma, mmap_state,
write_combine);
}
#endif
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);
}
#elif defined(HAVE_PCI_MMAP) /* && !ARCH_GENERIC_PCI_MMAP_RESOURCE */
/*
* Legacy setup: Impement pci_mmap_resource_range() as a wrapper around
* the architecture's pci_mmap_page_range(), converting to "user visible"
* addresses as necessary.
*/
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)
{
resource_size_t start, end;
/*
* pci_mmap_page_range() expects the same kind of entry as coming
* from /proc/bus/pci/ which is a "user visible" value. If this is
* different from the resource itself, arch will do necessary fixup.
*/
pci_resource_to_user(pdev, bar, &pdev->resource[bar], &start, &end);
vma->vm_pgoff += start >> PAGE_SHIFT;
return pci_mmap_page_range(pdev, bar, vma, mmap_state, write_combine);
}
#endif
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