1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * (C) Copyright 1995 1996 Linus Torvalds
 4 * (C) Copyright 2012 Regents of the University of California
 5 */
 6
 7#include <linux/export.h>
 8#include <linux/mm.h>
 9#include <linux/vmalloc.h>
10#include <linux/io.h>
11
12#include <asm/pgtable.h>
13
14/*
15 * Remap an arbitrary physical address space into the kernel virtual
16 * address space. Needed when the kernel wants to access high addresses
17 * directly.
18 *
19 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
20 * have to convert them into an offset in a page-aligned mapping, but the
21 * caller shouldn't need to know that small detail.
22 */
23static void __iomem *__ioremap_caller(phys_addr_t addr, size_t size,
24	pgprot_t prot, void *caller)
25{
26	phys_addr_t last_addr;
27	unsigned long offset, vaddr;
28	struct vm_struct *area;
29
30	/* Disallow wrap-around or zero size */
31	last_addr = addr + size - 1;
32	if (!size || last_addr < addr)
33		return NULL;
34
35	/* Page-align mappings */
36	offset = addr & (~PAGE_MASK);
37	addr -= offset;
38	size = PAGE_ALIGN(size + offset);
39
40	area = get_vm_area_caller(size, VM_IOREMAP, caller);
41	if (!area)
42		return NULL;
43	vaddr = (unsigned long)area->addr;
44
45	if (ioremap_page_range(vaddr, vaddr + size, addr, prot)) {
46		free_vm_area(area);
47		return NULL;
48	}
49
50	return (void __iomem *)(vaddr + offset);
51}
52
53/*
54 * ioremap     -   map bus memory into CPU space
55 * @offset:    bus address of the memory
56 * @size:      size of the resource to map
57 *
58 * ioremap performs a platform specific sequence of operations to
59 * make bus memory CPU accessible via the readb/readw/readl/writeb/
60 * writew/writel functions and the other mmio helpers. The returned
61 * address is not guaranteed to be usable directly as a virtual
62 * address.
63 *
64 * Must be freed with iounmap.
65 */
66void __iomem *ioremap(phys_addr_t offset, unsigned long size)
67{
68	return __ioremap_caller(offset, size, PAGE_KERNEL,
69		__builtin_return_address(0));
70}
71EXPORT_SYMBOL(ioremap);
72
73
74/**
75 * iounmap - Free a IO remapping
76 * @addr: virtual address from ioremap_*
77 *
78 * Caller must ensure there is only one unmapping for the same pointer.
79 */
80void iounmap(volatile void __iomem *addr)
81{
82	vunmap((void *)((unsigned long)addr & PAGE_MASK));
83}
84EXPORT_SYMBOL(iounmap);