xref: /openbmc/linux/mm/ioremap.c (revision 236bdb88)
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 
14 void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
15 			   unsigned long prot)
16 {
17 	unsigned long offset, vaddr;
18 	phys_addr_t last_addr;
19 	struct vm_struct *area;
20 
21 	/* Disallow wrap-around or zero size */
22 	last_addr = phys_addr + size - 1;
23 	if (!size || last_addr < phys_addr)
24 		return NULL;
25 
26 	/* Page-align mappings */
27 	offset = phys_addr & (~PAGE_MASK);
28 	phys_addr -= offset;
29 	size = PAGE_ALIGN(size + offset);
30 
31 	if (!ioremap_allowed(phys_addr, size, prot))
32 		return NULL;
33 
34 	area = get_vm_area_caller(size, VM_IOREMAP,
35 			__builtin_return_address(0));
36 	if (!area)
37 		return NULL;
38 	vaddr = (unsigned long)area->addr;
39 	area->phys_addr = phys_addr;
40 
41 	if (ioremap_page_range(vaddr, vaddr + size, phys_addr,
42 			       __pgprot(prot))) {
43 		free_vm_area(area);
44 		return NULL;
45 	}
46 
47 	return (void __iomem *)(vaddr + offset);
48 }
49 EXPORT_SYMBOL(ioremap_prot);
50 
51 void iounmap(volatile void __iomem *addr)
52 {
53 	void *vaddr = (void *)((unsigned long)addr & PAGE_MASK);
54 
55 	if (!iounmap_allowed(vaddr))
56 		return;
57 
58 	if (is_vmalloc_addr(vaddr))
59 		vunmap(vaddr);
60 }
61 EXPORT_SYMBOL(iounmap);
62