Merge branch 'for-linus' of git://brick.kernel.dk/data/git/linux-2.6-block
[linux-2.6] / arch / sh / mm / ioremap.c
1 /*
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
19 static 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
47 static 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
70 int 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  */
114 void * 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
159 void p3_iounmap(void *addr)
160 {
161         if (addr > high_memory)
162                 vfree((void *)(PAGE_MASK & (unsigned long)addr));
163 }