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1da177e4 LT |
1 | /* dma-alloc.c: consistent DMA memory allocation |
2 | * | |
3 | * Derived from arch/ppc/mm/cachemap.c | |
4 | * | |
5 | * PowerPC version derived from arch/arm/mm/consistent.c | |
6 | * Copyright (C) 2001 Dan Malek (dmalek@jlc.net) | |
7 | * | |
8 | * linux/arch/arm/mm/consistent.c | |
9 | * | |
10 | * Copyright (C) 2000 Russell King | |
11 | * | |
12 | * Consistent memory allocators. Used for DMA devices that want to | |
13 | * share uncached memory with the processor core. The function return | |
14 | * is the virtual address and 'dma_handle' is the physical address. | |
15 | * Mostly stolen from the ARM port, with some changes for PowerPC. | |
16 | * -- Dan | |
17 | * Modified for 36-bit support. -Matt | |
18 | * | |
19 | * This program is free software; you can redistribute it and/or modify | |
20 | * it under the terms of the GNU General Public License version 2 as | |
21 | * published by the Free Software Foundation. | |
22 | */ | |
23 | ||
24 | #include <linux/config.h> | |
25 | #include <linux/module.h> | |
26 | #include <linux/signal.h> | |
27 | #include <linux/sched.h> | |
28 | #include <linux/kernel.h> | |
29 | #include <linux/errno.h> | |
30 | #include <linux/string.h> | |
31 | #include <linux/types.h> | |
32 | #include <linux/ptrace.h> | |
33 | #include <linux/mman.h> | |
34 | #include <linux/mm.h> | |
35 | #include <linux/swap.h> | |
36 | #include <linux/stddef.h> | |
37 | #include <linux/vmalloc.h> | |
38 | #include <linux/init.h> | |
39 | #include <linux/pci.h> | |
40 | ||
41 | #include <asm/pgalloc.h> | |
42 | #include <asm/io.h> | |
43 | #include <asm/hardirq.h> | |
44 | #include <asm/mmu_context.h> | |
45 | #include <asm/pgtable.h> | |
46 | #include <asm/mmu.h> | |
47 | #include <asm/uaccess.h> | |
48 | #include <asm/smp.h> | |
49 | ||
50 | static int map_page(unsigned long va, unsigned long pa, pgprot_t prot) | |
51 | { | |
52 | pgd_t *pge; | |
53 | pud_t *pue; | |
54 | pmd_t *pme; | |
55 | pte_t *pte; | |
56 | int err = -ENOMEM; | |
57 | ||
58 | spin_lock(&init_mm.page_table_lock); | |
59 | ||
60 | /* Use upper 10 bits of VA to index the first level map */ | |
61 | pge = pgd_offset_k(va); | |
62 | pue = pud_offset(pge, va); | |
63 | pme = pmd_offset(pue, va); | |
64 | ||
65 | /* Use middle 10 bits of VA to index the second-level map */ | |
66 | pte = pte_alloc_kernel(&init_mm, pme, va); | |
67 | if (pte != 0) { | |
68 | err = 0; | |
69 | set_pte(pte, mk_pte_phys(pa & PAGE_MASK, prot)); | |
70 | } | |
71 | ||
72 | spin_unlock(&init_mm.page_table_lock); | |
73 | return err; | |
74 | } | |
75 | ||
76 | /* | |
77 | * This function will allocate the requested contiguous pages and | |
78 | * map them into the kernel's vmalloc() space. This is done so we | |
79 | * get unique mapping for these pages, outside of the kernel's 1:1 | |
80 | * virtual:physical mapping. This is necessary so we can cover large | |
81 | * portions of the kernel with single large page TLB entries, and | |
82 | * still get unique uncached pages for consistent DMA. | |
83 | */ | |
a5da7d3c | 84 | void *consistent_alloc(gfp_t gfp, size_t size, dma_addr_t *dma_handle) |
1da177e4 LT |
85 | { |
86 | struct vm_struct *area; | |
87 | unsigned long page, va, pa; | |
88 | void *ret; | |
89 | int order, err, i; | |
90 | ||
91 | if (in_interrupt()) | |
92 | BUG(); | |
93 | ||
94 | /* only allocate page size areas */ | |
95 | size = PAGE_ALIGN(size); | |
96 | order = get_order(size); | |
97 | ||
98 | page = __get_free_pages(gfp, order); | |
99 | if (!page) { | |
100 | BUG(); | |
101 | return NULL; | |
102 | } | |
103 | ||
104 | /* allocate some common virtual space to map the new pages */ | |
105 | area = get_vm_area(size, VM_ALLOC); | |
106 | if (area == 0) { | |
107 | free_pages(page, order); | |
108 | return NULL; | |
109 | } | |
110 | va = VMALLOC_VMADDR(area->addr); | |
111 | ret = (void *) va; | |
112 | ||
113 | /* this gives us the real physical address of the first page */ | |
114 | *dma_handle = pa = virt_to_bus((void *) page); | |
115 | ||
116 | /* set refcount=1 on all pages in an order>0 allocation so that vfree() will actually free | |
117 | * all pages that were allocated. | |
118 | */ | |
119 | if (order > 0) { | |
120 | struct page *rpage = virt_to_page(page); | |
121 | ||
122 | for (i = 1; i < (1 << order); i++) | |
123 | set_page_count(rpage + i, 1); | |
124 | } | |
125 | ||
126 | err = 0; | |
127 | for (i = 0; i < size && err == 0; i += PAGE_SIZE) | |
128 | err = map_page(va + i, pa + i, PAGE_KERNEL_NOCACHE); | |
129 | ||
130 | if (err) { | |
131 | vfree((void *) va); | |
132 | return NULL; | |
133 | } | |
134 | ||
135 | /* we need to ensure that there are no cachelines in use, or worse dirty in this area | |
136 | * - can't do until after virtual address mappings are created | |
137 | */ | |
138 | frv_cache_invalidate(va, va + size); | |
139 | ||
140 | return ret; | |
141 | } | |
142 | ||
143 | /* | |
144 | * free page(s) as defined by the above mapping. | |
145 | */ | |
146 | void consistent_free(void *vaddr) | |
147 | { | |
148 | if (in_interrupt()) | |
149 | BUG(); | |
150 | vfree(vaddr); | |
151 | } | |
152 | ||
153 | /* | |
154 | * make an area consistent. | |
155 | */ | |
156 | void consistent_sync(void *vaddr, size_t size, int direction) | |
157 | { | |
158 | unsigned long start = (unsigned long) vaddr; | |
159 | unsigned long end = start + size; | |
160 | ||
161 | switch (direction) { | |
162 | case PCI_DMA_NONE: | |
163 | BUG(); | |
164 | case PCI_DMA_FROMDEVICE: /* invalidate only */ | |
165 | frv_cache_invalidate(start, end); | |
166 | break; | |
167 | case PCI_DMA_TODEVICE: /* writeback only */ | |
168 | frv_dcache_writeback(start, end); | |
169 | break; | |
170 | case PCI_DMA_BIDIRECTIONAL: /* writeback and invalidate */ | |
171 | frv_dcache_writeback(start, end); | |
172 | break; | |
173 | } | |
174 | } | |
175 | ||
176 | /* | |
177 | * consistent_sync_page make a page are consistent. identical | |
178 | * to consistent_sync, but takes a struct page instead of a virtual address | |
179 | */ | |
180 | ||
181 | void consistent_sync_page(struct page *page, unsigned long offset, | |
182 | size_t size, int direction) | |
183 | { | |
184 | void *start; | |
185 | ||
186 | start = page_address(page) + offset; | |
187 | consistent_sync(start, size, direction); | |
188 | } |