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1da177e4 LT |
1 | /* |
2 | * arch/s390/mm/ioremap.c | |
3 | * | |
4 | * S390 version | |
5 | * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation | |
6 | * Author(s): Hartmut Penner (hp@de.ibm.com) | |
7 | * | |
8 | * Derived from "arch/i386/mm/extable.c" | |
9 | * (C) Copyright 1995 1996 Linus Torvalds | |
10 | * | |
11 | * Re-map IO memory to kernel address space so that we can access it. | |
12 | * This is needed for high PCI addresses that aren't mapped in the | |
13 | * 640k-1MB IO memory area on PC's | |
14 | */ | |
15 | ||
16 | #include <linux/vmalloc.h> | |
17 | #include <linux/mm.h> | |
18 | #include <asm/io.h> | |
19 | #include <asm/pgalloc.h> | |
20 | #include <asm/cacheflush.h> | |
21 | #include <asm/tlbflush.h> | |
22 | ||
23 | static inline void remap_area_pte(pte_t * pte, unsigned long address, unsigned long size, | |
24 | unsigned long phys_addr, unsigned long flags) | |
25 | { | |
26 | unsigned long end; | |
27 | unsigned long pfn; | |
28 | ||
29 | address &= ~PMD_MASK; | |
30 | end = address + size; | |
31 | if (end > PMD_SIZE) | |
32 | end = PMD_SIZE; | |
33 | if (address >= end) | |
34 | BUG(); | |
35 | pfn = phys_addr >> PAGE_SHIFT; | |
36 | do { | |
37 | if (!pte_none(*pte)) { | |
38 | printk("remap_area_pte: page already exists\n"); | |
39 | BUG(); | |
40 | } | |
41 | set_pte(pte, pfn_pte(pfn, __pgprot(flags))); | |
42 | address += PAGE_SIZE; | |
43 | pfn++; | |
44 | pte++; | |
45 | } while (address && (address < end)); | |
46 | } | |
47 | ||
48 | static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size, | |
49 | unsigned long phys_addr, unsigned long flags) | |
50 | { | |
51 | unsigned long end; | |
52 | ||
53 | address &= ~PGDIR_MASK; | |
54 | end = address + size; | |
55 | if (end > PGDIR_SIZE) | |
56 | end = PGDIR_SIZE; | |
57 | phys_addr -= address; | |
58 | if (address >= end) | |
59 | BUG(); | |
60 | do { | |
61 | pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address); | |
62 | if (!pte) | |
63 | return -ENOMEM; | |
64 | remap_area_pte(pte, address, end - address, address + phys_addr, flags); | |
65 | address = (address + PMD_SIZE) & PMD_MASK; | |
66 | pmd++; | |
67 | } while (address && (address < end)); | |
68 | return 0; | |
69 | } | |
70 | ||
71 | static int remap_area_pages(unsigned long address, unsigned long phys_addr, | |
72 | unsigned long size, unsigned long flags) | |
73 | { | |
74 | int error; | |
75 | pgd_t * dir; | |
76 | unsigned long end = address + size; | |
77 | ||
78 | phys_addr -= address; | |
79 | dir = pgd_offset(&init_mm, address); | |
80 | flush_cache_all(); | |
81 | if (address >= end) | |
82 | BUG(); | |
83 | spin_lock(&init_mm.page_table_lock); | |
84 | do { | |
85 | pmd_t *pmd; | |
86 | pmd = pmd_alloc(&init_mm, dir, address); | |
87 | error = -ENOMEM; | |
88 | if (!pmd) | |
89 | break; | |
90 | if (remap_area_pmd(pmd, address, end - address, | |
91 | phys_addr + address, flags)) | |
92 | break; | |
93 | error = 0; | |
94 | address = (address + PGDIR_SIZE) & PGDIR_MASK; | |
95 | dir++; | |
96 | } while (address && (address < end)); | |
97 | spin_unlock(&init_mm.page_table_lock); | |
98 | flush_tlb_all(); | |
99 | return 0; | |
100 | } | |
101 | ||
102 | /* | |
103 | * Generic mapping function (not visible outside): | |
104 | */ | |
105 | ||
106 | /* | |
107 | * Remap an arbitrary physical address space into the kernel virtual | |
108 | * address space. Needed when the kernel wants to access high addresses | |
109 | * directly. | |
110 | */ | |
111 | void * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags) | |
112 | { | |
113 | void * addr; | |
114 | struct vm_struct * area; | |
115 | ||
116 | if (phys_addr < virt_to_phys(high_memory)) | |
117 | return phys_to_virt(phys_addr); | |
118 | if (phys_addr & ~PAGE_MASK) | |
119 | return NULL; | |
120 | size = PAGE_ALIGN(size); | |
121 | if (!size || size > phys_addr + size) | |
122 | return NULL; | |
123 | area = get_vm_area(size, VM_IOREMAP); | |
124 | if (!area) | |
125 | return NULL; | |
126 | addr = area->addr; | |
127 | if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) { | |
128 | vfree(addr); | |
129 | return NULL; | |
130 | } | |
131 | return addr; | |
132 | } | |
133 | ||
134 | void iounmap(void *addr) | |
135 | { | |
136 | if (addr > high_memory) | |
137 | vfree(addr); | |
138 | } |