96 lines
2.7 KiB
C
96 lines
2.7 KiB
C
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/*
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* mmap.c — generic PCI resource mmap helper
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*
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* Copyright © 2017 Amazon.com, Inc. or its affiliates.
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*
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* Author: David Woodhouse <dwmw2@infradead.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/pci.h>
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#ifdef ARCH_GENERIC_PCI_MMAP_RESOURCE
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/*
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* Modern setup: generic pci_mmap_resource_range(), and implement the legacy
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* pci_mmap_page_range() (if needed) as a wrapper round it.
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*/
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#ifdef HAVE_PCI_MMAP
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int pci_mmap_page_range(struct pci_dev *pdev, int bar,
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struct vm_area_struct *vma,
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enum pci_mmap_state mmap_state, int write_combine)
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{
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resource_size_t start, end;
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pci_resource_to_user(pdev, bar, &pdev->resource[bar], &start, &end);
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/* Adjust vm_pgoff to be the offset within the resource */
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vma->vm_pgoff -= start >> PAGE_SHIFT;
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return pci_mmap_resource_range(pdev, bar, vma, mmap_state,
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write_combine);
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}
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#endif
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static const struct vm_operations_struct pci_phys_vm_ops = {
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#ifdef CONFIG_HAVE_IOREMAP_PROT
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.access = generic_access_phys,
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#endif
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};
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int pci_mmap_resource_range(struct pci_dev *pdev, int bar,
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struct vm_area_struct *vma,
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enum pci_mmap_state mmap_state, int write_combine)
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{
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unsigned long size;
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if (mmap_state == pci_mmap_io)
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return -EINVAL;
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size = ((pci_resource_len(pdev, bar) - 1) >> PAGE_SHIFT) + 1;
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if (vma->vm_pgoff + vma_pages(vma) > size)
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return -EINVAL;
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if (write_combine)
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vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
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else
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vma->vm_page_prot = pgprot_device(vma->vm_page_prot);
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vma->vm_pgoff += (pci_resource_start(pdev, bar) >> PAGE_SHIFT);
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vma->vm_ops = &pci_phys_vm_ops;
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return io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
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vma->vm_end - vma->vm_start,
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vma->vm_page_prot);
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}
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#elif defined(HAVE_PCI_MMAP) /* && !ARCH_GENERIC_PCI_MMAP_RESOURCE */
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/*
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* Legacy setup: Impement pci_mmap_resource_range() as a wrapper around
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* the architecture's pci_mmap_page_range(), converting to "user visible"
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* addresses as necessary.
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*/
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int pci_mmap_resource_range(struct pci_dev *pdev, int bar,
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struct vm_area_struct *vma,
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enum pci_mmap_state mmap_state, int write_combine)
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{
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resource_size_t start, end;
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/*
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* pci_mmap_page_range() expects the same kind of entry as coming
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* from /proc/bus/pci/ which is a "user visible" value. If this is
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* different from the resource itself, arch will do necessary fixup.
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*/
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pci_resource_to_user(pdev, bar, &pdev->resource[bar], &start, &end);
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vma->vm_pgoff += start >> PAGE_SHIFT;
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return pci_mmap_page_range(pdev, bar, vma, mmap_state, write_combine);
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}
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#endif
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