1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Generic PCI resource mmap helper 4 * 5 * Copyright © 2017 Amazon.com, Inc. or its affiliates. 6 * 7 * Author: David Woodhouse <dwmw2@infradead.org> 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/mm.h> 12 #include <linux/pci.h> 13 14 #ifdef ARCH_GENERIC_PCI_MMAP_RESOURCE 15 16 /* 17 * Modern setup: generic pci_mmap_resource_range(), and implement the legacy 18 * pci_mmap_page_range() (if needed) as a wrapper round it. 19 */ 20 21 #ifdef HAVE_PCI_MMAP 22 int pci_mmap_page_range(struct pci_dev *pdev, int bar, 23 struct vm_area_struct *vma, 24 enum pci_mmap_state mmap_state, int write_combine) 25 { 26 resource_size_t start, end; 27 28 pci_resource_to_user(pdev, bar, &pdev->resource[bar], &start, &end); 29 30 /* Adjust vm_pgoff to be the offset within the resource */ 31 vma->vm_pgoff -= start >> PAGE_SHIFT; 32 return pci_mmap_resource_range(pdev, bar, vma, mmap_state, 33 write_combine); 34 } 35 #endif 36 37 static const struct vm_operations_struct pci_phys_vm_ops = { 38 #ifdef CONFIG_HAVE_IOREMAP_PROT 39 .access = generic_access_phys, 40 #endif 41 }; 42 43 int pci_mmap_resource_range(struct pci_dev *pdev, int bar, 44 struct vm_area_struct *vma, 45 enum pci_mmap_state mmap_state, int write_combine) 46 { 47 unsigned long size; 48 int ret; 49 50 size = ((pci_resource_len(pdev, bar) - 1) >> PAGE_SHIFT) + 1; 51 if (vma->vm_pgoff + vma_pages(vma) > size) 52 return -EINVAL; 53 54 if (write_combine) 55 vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot); 56 else 57 vma->vm_page_prot = pgprot_device(vma->vm_page_prot); 58 59 if (mmap_state == pci_mmap_io) { 60 ret = pci_iobar_pfn(pdev, bar, vma); 61 if (ret) 62 return ret; 63 } else 64 vma->vm_pgoff += (pci_resource_start(pdev, bar) >> PAGE_SHIFT); 65 66 vma->vm_ops = &pci_phys_vm_ops; 67 68 return io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, 69 vma->vm_end - vma->vm_start, 70 vma->vm_page_prot); 71 } 72 73 #elif defined(HAVE_PCI_MMAP) /* && !ARCH_GENERIC_PCI_MMAP_RESOURCE */ 74 75 /* 76 * Legacy setup: Impement pci_mmap_resource_range() as a wrapper around 77 * the architecture's pci_mmap_page_range(), converting to "user visible" 78 * addresses as necessary. 79 */ 80 81 int pci_mmap_resource_range(struct pci_dev *pdev, int bar, 82 struct vm_area_struct *vma, 83 enum pci_mmap_state mmap_state, int write_combine) 84 { 85 resource_size_t start, end; 86 87 /* 88 * pci_mmap_page_range() expects the same kind of entry as coming 89 * from /proc/bus/pci/ which is a "user visible" value. If this is 90 * different from the resource itself, arch will do necessary fixup. 91 */ 92 pci_resource_to_user(pdev, bar, &pdev->resource[bar], &start, &end); 93 vma->vm_pgoff += start >> PAGE_SHIFT; 94 return pci_mmap_page_range(pdev, bar, vma, mmap_state, write_combine); 95 } 96 #endif 97