blob: 9f490c2742f06576b47a9436699928356c375a1d [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * arch/sh/mm/ioremap.c
3 *
4 * Re-map IO memory to kernel address space so that we can access it.
5 * This is needed for high PCI addresses that aren't mapped in the
6 * 640k-1MB IO memory area on PC's
7 *
8 * (C) Copyright 1995 1996 Linus Torvalds
9 */
10
11#include <linux/vmalloc.h>
12#include <linux/mm.h>
13#include <asm/io.h>
14#include <asm/page.h>
15#include <asm/pgalloc.h>
16#include <asm/cacheflush.h>
17#include <asm/tlbflush.h>
18
19static inline void remap_area_pte(pte_t * pte, unsigned long address,
20 unsigned long size, unsigned long phys_addr, unsigned long flags)
21{
22 unsigned long end;
23 unsigned long pfn;
24 pgprot_t pgprot = __pgprot(_PAGE_PRESENT | _PAGE_RW |
25 _PAGE_DIRTY | _PAGE_ACCESSED |
26 _PAGE_HW_SHARED | _PAGE_FLAGS_HARD | flags);
27
28 address &= ~PMD_MASK;
29 end = address + size;
30 if (end > PMD_SIZE)
31 end = PMD_SIZE;
32 if (address >= end)
33 BUG();
34 pfn = phys_addr >> PAGE_SHIFT;
35 do {
36 if (!pte_none(*pte)) {
37 printk("remap_area_pte: page already exists\n");
38 BUG();
39 }
40 set_pte(pte, pfn_pte(pfn, pgprot));
41 address += PAGE_SIZE;
42 pfn++;
43 pte++;
44 } while (address && (address < end));
45}
46
47static inline int remap_area_pmd(pmd_t * pmd, unsigned long address,
48 unsigned long size, unsigned long phys_addr, unsigned long flags)
49{
50 unsigned long end;
51
52 address &= ~PGDIR_MASK;
53 end = address + size;
54 if (end > PGDIR_SIZE)
55 end = PGDIR_SIZE;
56 phys_addr -= address;
57 if (address >= end)
58 BUG();
59 do {
60 pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address);
61 if (!pte)
62 return -ENOMEM;
63 remap_area_pte(pte, address, end - address, address + phys_addr, flags);
64 address = (address + PMD_SIZE) & PMD_MASK;
65 pmd++;
66 } while (address && (address < end));
67 return 0;
68}
69
70int remap_area_pages(unsigned long address, unsigned long phys_addr,
71 unsigned long size, unsigned long flags)
72{
73 int error;
74 pgd_t * dir;
75 unsigned long end = address + size;
76
77 phys_addr -= address;
78 dir = pgd_offset_k(address);
79 flush_cache_all();
80 if (address >= end)
81 BUG();
82 spin_lock(&init_mm.page_table_lock);
83 do {
84 pmd_t *pmd;
85 pmd = pmd_alloc(&init_mm, dir, address);
86 error = -ENOMEM;
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 spin_unlock(&init_mm.page_table_lock);
97 flush_tlb_all();
98 return error;
99}
100
101/*
102 * Generic mapping function (not visible outside):
103 */
104
105/*
106 * Remap an arbitrary physical address space into the kernel virtual
107 * address space. Needed when the kernel wants to access high addresses
108 * directly.
109 *
110 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
111 * have to convert them into an offset in a page-aligned mapping, but the
112 * caller shouldn't need to know that small detail.
113 */
114void * p3_ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
115{
116 void * addr;
117 struct vm_struct * area;
118 unsigned long offset, last_addr;
119
120 /* Don't allow wraparound or zero size */
121 last_addr = phys_addr + size - 1;
122 if (!size || last_addr < phys_addr)
123 return NULL;
124
125 /*
126 * Don't remap the low PCI/ISA area, it's always mapped..
127 */
128 if (phys_addr >= 0xA0000 && last_addr < 0x100000)
129 return phys_to_virt(phys_addr);
130
131 /*
132 * Don't allow anybody to remap normal RAM that we're using..
133 */
134 if (phys_addr < virt_to_phys(high_memory))
135 return NULL;
136
137 /*
138 * Mappings have to be page-aligned
139 */
140 offset = phys_addr & ~PAGE_MASK;
141 phys_addr &= PAGE_MASK;
142 size = PAGE_ALIGN(last_addr+1) - phys_addr;
143
144 /*
145 * Ok, go for it..
146 */
147 area = get_vm_area(size, VM_IOREMAP);
148 if (!area)
149 return NULL;
150 area->phys_addr = phys_addr;
151 addr = area->addr;
152 if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) {
153 vunmap(addr);
154 return NULL;
155 }
156 return (void *) (offset + (char *)addr);
157}
158
159void p3_iounmap(void *addr)
160{
161 if (addr > high_memory)
162 vfree((void *)(PAGE_MASK & (unsigned long)addr));
163}