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/sched.h>
12#include <linux/io.h>
13#include <linux/export.h>
14#include <asm/cacheflush.h>
15
16#include "pgalloc-track.h"
17
18#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
19static unsigned int __ro_after_init iomap_max_page_shift = BITS_PER_LONG - 1;
20
21static int __init set_nohugeiomap(char *str)
22{
23	iomap_max_page_shift = PAGE_SHIFT;
24	return 0;
25}
26early_param("nohugeiomap", set_nohugeiomap);
27#else /* CONFIG_HAVE_ARCH_HUGE_VMAP */
28static const unsigned int iomap_max_page_shift = PAGE_SHIFT;
29#endif	/* CONFIG_HAVE_ARCH_HUGE_VMAP */
30
31int ioremap_page_range(unsigned long addr,
32		       unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
33{
34	return vmap_range(addr, end, phys_addr, prot, iomap_max_page_shift);
35}
36
37#ifdef CONFIG_GENERIC_IOREMAP
38void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long prot)
39{
40	unsigned long offset, vaddr;
41	phys_addr_t last_addr;
42	struct vm_struct *area;
43
44	/* Disallow wrap-around or zero size */
45	last_addr = addr + size - 1;
46	if (!size || last_addr < addr)
47		return NULL;
48
49	/* Page-align mappings */
50	offset = addr & (~PAGE_MASK);
51	addr -= offset;
52	size = PAGE_ALIGN(size + offset);
53
54	area = get_vm_area_caller(size, VM_IOREMAP,
55			__builtin_return_address(0));
56	if (!area)
57		return NULL;
58	vaddr = (unsigned long)area->addr;
59
60	if (ioremap_page_range(vaddr, vaddr + size, addr, __pgprot(prot))) {
61		free_vm_area(area);
62		return NULL;
63	}
64
65	return (void __iomem *)(vaddr + offset);
66}
67EXPORT_SYMBOL(ioremap_prot);
68
69void iounmap(volatile void __iomem *addr)
70{
71	vunmap((void *)((unsigned long)addr & PAGE_MASK));
72}
73EXPORT_SYMBOL(iounmap);
74#endif /* CONFIG_GENERIC_IOREMAP */