1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * (C) Copyright 1995 1996 Linus Torvalds
7 * (C) Copyright 2001, 2002 Ralf Baechle
8 */
9#include <linux/module.h>
10#include <asm/addrspace.h>
11#include <asm/byteorder.h>
12#include <linux/sched.h>
13#include <linux/slab.h>
14#include <linux/vmalloc.h>
15#include <asm/cacheflush.h>
16#include <asm/io.h>
17#include <asm/tlbflush.h>
18
19static inline void remap_area_pte(pte_t * pte, unsigned long address,
20	phys_addr_t size, phys_addr_t phys_addr, unsigned long flags)
21{
22	phys_addr_t end;
23	unsigned long pfn;
24	pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | __READABLE
25				   | __WRITEABLE | flags);
26
27	address &= ~PMD_MASK;
28	end = address + size;
29	if (end > PMD_SIZE)
30		end = PMD_SIZE;
31	BUG_ON(address >= end);
32	pfn = phys_addr >> PAGE_SHIFT;
33	do {
34		if (!pte_none(*pte)) {
35			printk("remap_area_pte: page already exists\n");
36			BUG();
37		}
38		set_pte(pte, pfn_pte(pfn, pgprot));
39		address += PAGE_SIZE;
40		pfn++;
41		pte++;
42	} while (address && (address < end));
43}
44
45static inline int remap_area_pmd(pmd_t * pmd, unsigned long address,
46	phys_addr_t size, phys_addr_t phys_addr, unsigned long flags)
47{
48	phys_addr_t end;
49
50	address &= ~PGDIR_MASK;
51	end = address + size;
52	if (end > PGDIR_SIZE)
53		end = PGDIR_SIZE;
54	phys_addr -= address;
55	BUG_ON(address >= end);
56	do {
57		pte_t * pte = pte_alloc_kernel(pmd, address);
58		if (!pte)
59			return -ENOMEM;
60		remap_area_pte(pte, address, end - address, address + phys_addr, flags);
61		address = (address + PMD_SIZE) & PMD_MASK;
62		pmd++;
63	} while (address && (address < end));
64	return 0;
65}
66
67static int remap_area_pages(unsigned long address, phys_addr_t phys_addr,
68	phys_addr_t size, unsigned long flags)
69{
70	int error;
71	pgd_t * dir;
72	unsigned long end = address + size;
73
74	phys_addr -= address;
75	dir = pgd_offset(&init_mm, address);
76	flush_cache_all();
77	BUG_ON(address >= end);
78	do {
79		pud_t *pud;
80		pmd_t *pmd;
81
82		error = -ENOMEM;
83		pud = pud_alloc(&init_mm, dir, address);
84		if (!pud)
85			break;
86		pmd = pmd_alloc(&init_mm, pud, address);
87		if (!pmd)
88			break;
89		if (remap_area_pmd(pmd, address, end - address,
90					 phys_addr + address, flags))
91			break;
92		error = 0;
93		address = (address + PGDIR_SIZE) & PGDIR_MASK;
94		dir++;
95	} while (address && (address < end));
96	flush_tlb_all();
97	return error;
98}
99
100/*
101 * Generic mapping function (not visible outside):
102 */
103
104/*
105 * Remap an arbitrary physical address space into the kernel virtual
106 * address space. Needed when the kernel wants to access high addresses
107 * directly.
108 *
109 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
110 * have to convert them into an offset in a page-aligned mapping, but the
111 * caller shouldn't need to know that small detail.
112 */
113
114#define IS_LOW512(addr) (!((phys_addr_t)(addr) & (phys_addr_t) ~0x1fffffffULL))
115
116void __iomem * __ioremap(phys_addr_t phys_addr, phys_addr_t size, unsigned long flags)
117{
118	struct vm_struct * area;
119	unsigned long offset;
120	phys_addr_t last_addr;
121	void * addr;
122
123	phys_addr = fixup_bigphys_addr(phys_addr, size);
124
125	/* Don't allow wraparound or zero size */
126	last_addr = phys_addr + size - 1;
127	if (!size || last_addr < phys_addr)
128		return NULL;
129
130	/*
131	 * Map uncached objects in the low 512mb of address space using KSEG1,
132	 * otherwise map using page tables.
133	 */
134	if (IS_LOW512(phys_addr) && IS_LOW512(last_addr) &&
135	    flags == _CACHE_UNCACHED)
136		return (void __iomem *) CKSEG1ADDR(phys_addr);
137
138	/*
139	 * Don't allow anybody to remap normal RAM that we're using..
140	 */
141	if (phys_addr < virt_to_phys(high_memory)) {
142		char *t_addr, *t_end;
143		struct page *page;
144
145		t_addr = __va(phys_addr);
146		t_end = t_addr + (size - 1);
147
148		for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++)
149			if(!PageReserved(page))
150				return NULL;
151	}
152
153	/*
154	 * Mappings have to be page-aligned
155	 */
156	offset = phys_addr & ~PAGE_MASK;
157	phys_addr &= PAGE_MASK;
158	size = PAGE_ALIGN(last_addr + 1) - phys_addr;
159
160	/*
161	 * Ok, go for it..
162	 */
163	area = get_vm_area(size, VM_IOREMAP);
164	if (!area)
165		return NULL;
166	addr = area->addr;
167	if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) {
168		vunmap(addr);
169		return NULL;
170	}
171
172	return (void __iomem *) (offset + (char *)addr);
173}
174
175#define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == CKSEG1)
176
177void __iounmap(const volatile void __iomem *addr)
178{
179	struct vm_struct *p;
180
181	if (IS_KSEG1(addr))
182		return;
183
184	p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr));
185	if (!p)
186		printk(KERN_ERR "iounmap: bad address %p\n", addr);
187
188	kfree(p);
189}
190
191EXPORT_SYMBOL(__ioremap);
192EXPORT_SYMBOL(__iounmap);
193