ARM: Add init_consistent_dma_size()
[linux-3.10.git] / arch / arm / mm / highmem.c
1 /*
2  * arch/arm/mm/highmem.c -- ARM highmem support
3  *
4  * Author:      Nicolas Pitre
5  * Created:     september 8, 2008
6  * Copyright:   Marvell Semiconductors Inc.
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  */
12
13 #include <linux/module.h>
14 #include <linux/highmem.h>
15 #include <linux/interrupt.h>
16 #include <asm/fixmap.h>
17 #include <asm/cacheflush.h>
18 #include <asm/tlbflush.h>
19 #include "mm.h"
20
21 void *kmap(struct page *page)
22 {
23         might_sleep();
24         if (!PageHighMem(page))
25                 return page_address(page);
26         return kmap_high(page);
27 }
28 EXPORT_SYMBOL(kmap);
29
30 void kunmap(struct page *page)
31 {
32         BUG_ON(in_interrupt());
33         if (!PageHighMem(page))
34                 return;
35         kunmap_high(page);
36 }
37 EXPORT_SYMBOL(kunmap);
38
39 void *__kmap_atomic(struct page *page)
40 {
41         unsigned int idx;
42         unsigned long vaddr;
43         void *kmap;
44         int type;
45
46         pagefault_disable();
47         if (!PageHighMem(page))
48                 return page_address(page);
49
50 #ifdef CONFIG_DEBUG_HIGHMEM
51         /*
52          * There is no cache coherency issue when non VIVT, so force the
53          * dedicated kmap usage for better debugging purposes in that case.
54          */
55         if (!cache_is_vivt())
56                 kmap = NULL;
57         else
58 #endif
59                 kmap = kmap_high_get(page);
60         if (kmap)
61                 return kmap;
62
63         type = kmap_atomic_idx_push();
64
65         idx = type + KM_TYPE_NR * smp_processor_id();
66         vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
67 #ifdef CONFIG_DEBUG_HIGHMEM
68         /*
69          * With debugging enabled, kunmap_atomic forces that entry to 0.
70          * Make sure it was indeed properly unmapped.
71          */
72         BUG_ON(!pte_none(*(TOP_PTE(vaddr))));
73 #endif
74         set_pte_ext(TOP_PTE(vaddr), mk_pte(page, kmap_prot), 0);
75         /*
76          * When debugging is off, kunmap_atomic leaves the previous mapping
77          * in place, so this TLB flush ensures the TLB is updated with the
78          * new mapping.
79          */
80         local_flush_tlb_kernel_page(vaddr);
81
82         return (void *)vaddr;
83 }
84 EXPORT_SYMBOL(__kmap_atomic);
85
86 void __kunmap_atomic(void *kvaddr)
87 {
88         unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
89         int idx, type;
90
91         if (kvaddr >= (void *)FIXADDR_START) {
92                 type = kmap_atomic_idx();
93                 idx = type + KM_TYPE_NR * smp_processor_id();
94
95                 if (cache_is_vivt())
96                         __cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
97 #ifdef CONFIG_DEBUG_HIGHMEM
98                 BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
99                 set_pte_ext(TOP_PTE(vaddr), __pte(0), 0);
100                 local_flush_tlb_kernel_page(vaddr);
101 #else
102                 (void) idx;  /* to kill a warning */
103 #endif
104                 kmap_atomic_idx_pop();
105         } else if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
106                 /* this address was obtained through kmap_high_get() */
107                 kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
108         }
109         pagefault_enable();
110 }
111 EXPORT_SYMBOL(__kunmap_atomic);
112
113 void *kmap_atomic_pfn(unsigned long pfn)
114 {
115         unsigned long vaddr;
116         int idx, type;
117
118         pagefault_disable();
119
120         type = kmap_atomic_idx_push();
121         idx = type + KM_TYPE_NR * smp_processor_id();
122         vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
123 #ifdef CONFIG_DEBUG_HIGHMEM
124         BUG_ON(!pte_none(*(TOP_PTE(vaddr))));
125 #endif
126         set_pte_ext(TOP_PTE(vaddr), pfn_pte(pfn, kmap_prot), 0);
127         local_flush_tlb_kernel_page(vaddr);
128
129         return (void *)vaddr;
130 }
131
132 struct page *kmap_atomic_to_page(const void *ptr)
133 {
134         unsigned long vaddr = (unsigned long)ptr;
135         pte_t *pte;
136
137         if (vaddr < FIXADDR_START)
138                 return virt_to_page(ptr);
139
140         pte = TOP_PTE(vaddr);
141         return pte_page(*pte);
142 }