1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Re-map IO memory to kernel address space so that we can access it.
4 * This is needed for high PCI addresses that aren't mapped in the
5 * 640k-1MB IO memory area on PC's
6 *
7 * (C) Copyright 1995 1996 Linus Torvalds
8 */
9#include <linux/vmalloc.h>
10#include <linux/mm.h>
11#include <linux/io.h>
12#include <linux/export.h>
13#include <linux/ioremap.h>
14
15void __iomem *generic_ioremap_prot(phys_addr_t phys_addr, size_t size,
16 pgprot_t prot)
17{
18 unsigned long offset, vaddr;
19 phys_addr_t last_addr;
20 struct vm_struct *area;
21
22 /* An early platform driver might end up here */
23 if (WARN_ON_ONCE(!slab_is_available()))
24 return NULL;
25
26 /* Disallow wrap-around or zero size */
27 last_addr = phys_addr + size - 1;
28 if (!size || last_addr < phys_addr)
29 return NULL;
30
31 /* Page-align mappings */
32 offset = phys_addr & (~PAGE_MASK);
33 phys_addr -= offset;
34 size = PAGE_ALIGN(size + offset);
35
36 area = __get_vm_area_caller(size, VM_IOREMAP, IOREMAP_START,
37 IOREMAP_END, caller: __builtin_return_address(0));
38 if (!area)
39 return NULL;
40 vaddr = (unsigned long)area->addr;
41 area->phys_addr = phys_addr;
42
43 if (ioremap_page_range(addr: vaddr, end: vaddr + size, phys_addr, prot)) {
44 free_vm_area(area);
45 return NULL;
46 }
47
48 return (void __iomem *)(vaddr + offset);
49}
50
51#ifndef ioremap_prot
52void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
53 pgprot_t prot)
54{
55 return generic_ioremap_prot(phys_addr, size, prot);
56}
57EXPORT_SYMBOL(ioremap_prot);
58#endif
59
60void generic_iounmap(volatile void __iomem *addr)
61{
62 void *vaddr = (void *)((unsigned long)addr & PAGE_MASK);
63
64 if (is_ioremap_addr(x: vaddr))
65 vunmap(addr: vaddr);
66}
67
68#ifndef iounmap
69void iounmap(volatile void __iomem *addr)
70{
71 generic_iounmap(addr);
72}
73EXPORT_SYMBOL(iounmap);
74#endif
75

source code of linux/mm/ioremap.c