1/*
2 * Re-map IO memory to kernel address space so that we can access it.
3 * This is needed for high PCI addresses that aren't mapped in the
4 * 640k-1MB IO memory area on PC's
5 *
6 * (C) Copyright 1995 1996 Linus Torvalds
7 */
8#include <linux/vmalloc.h>
9#include <linux/mm.h>
10#include <linux/sched.h>
11#include <linux/io.h>
12#include <asm/cacheflush.h>
13#include <asm/pgtable.h>
14
15static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
16		unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
17{
18	pte_t *pte;
19	u64 pfn;
20
21	pfn = phys_addr >> PAGE_SHIFT;
22	pte = pte_alloc_kernel(pmd, addr);
23	if (!pte)
24		return -ENOMEM;
25	do {
26		BUG_ON(!pte_none(*pte));
27		set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
28		pfn++;
29	} while (pte++, addr += PAGE_SIZE, addr != end);
30	return 0;
31}
32
33static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
34		unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
35{
36	pmd_t *pmd;
37	unsigned long next;
38
39	phys_addr -= addr;
40	pmd = pmd_alloc(&init_mm, pud, addr);
41	if (!pmd)
42		return -ENOMEM;
43	do {
44		next = pmd_addr_end(addr, end);
45		if (ioremap_pte_range(pmd, addr, next, phys_addr + addr, prot))
46			return -ENOMEM;
47	} while (pmd++, addr = next, addr != end);
48	return 0;
49}
50
51static inline int ioremap_pud_range(pgd_t *pgd, unsigned long addr,
52		unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
53{
54	pud_t *pud;
55	unsigned long next;
56
57	phys_addr -= addr;
58	pud = pud_alloc(&init_mm, pgd, addr);
59	if (!pud)
60		return -ENOMEM;
61	do {
62		next = pud_addr_end(addr, end);
63		if (ioremap_pmd_range(pud, addr, next, phys_addr + addr, prot))
64			return -ENOMEM;
65	} while (pud++, addr = next, addr != end);
66	return 0;
67}
68
69int ioremap_page_range(unsigned long addr,
70		       unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
71{
72	pgd_t *pgd;
73	unsigned long start;
74	unsigned long next;
75	int err;
76
77	BUG_ON(addr >= end);
78
79	start = addr;
80	phys_addr -= addr;
81	pgd = pgd_offset_k(addr);
82	do {
83		next = pgd_addr_end(addr, end);
84		err = ioremap_pud_range(pgd, addr, next, phys_addr+addr, prot);
85		if (err)
86			break;
87	} while (pgd++, addr = next, addr != end);
88
89	flush_cache_vmap(start, end);
90
91	return err;
92}
93