drivers/pci/mmap.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Generic PCI resource mmap helper
0004  *
0005  * Copyright © 2017 Amazon.com, Inc. or its affiliates.
0006  *
0007  * Author: David Woodhouse <dwmw2@infradead.org>
0008  */
0009
0010 #include <linux/kernel.h>
0011 #include <linux/mm.h>
0012 #include <linux/pci.h>
0013
0014 #ifdef ARCH_GENERIC_PCI_MMAP_RESOURCE
0015
0016 static const struct vm_operations_struct pci_phys_vm_ops = {
0017 #ifdef CONFIG_HAVE_IOREMAP_PROT
0018     .access = generic_access_phys,
0019 #endif
0020 };
0021
0022 int pci_mmap_resource_range(struct pci_dev *pdev, int bar,
0023                 struct vm_area_struct *vma,
0024                 enum pci_mmap_state mmap_state, int write_combine)
0025 {
0026     unsigned long size;
0027     int ret;
0028
0029     size = ((pci_resource_len(pdev, bar) - 1) >> PAGE_SHIFT) + 1;
0030     if (vma->vm_pgoff + vma_pages(vma) > size)
0031         return -EINVAL;
0032
0033     if (write_combine)
0034         vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
0035     else
0036         vma->vm_page_prot = pgprot_device(vma->vm_page_prot);
0037
0038     if (mmap_state == pci_mmap_io) {
0039         ret = pci_iobar_pfn(pdev, bar, vma);
0040         if (ret)
0041             return ret;
0042     } else
0043         vma->vm_pgoff += (pci_resource_start(pdev, bar) >> PAGE_SHIFT);
0044
0045     vma->vm_ops = &pci_phys_vm_ops;
0046
0047     return io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
0048                   vma->vm_end - vma->vm_start,
0049                   vma->vm_page_prot);
0050 }
0051
0052 #endif