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/module.h>
25 #include <linux/signal.h>
26 #include <linux/sched.h>
27 #include <linux/kernel.h>
28 #include <linux/errno.h>
29 #include <linux/string.h>
30 #include <linux/types.h>
31 #include <linux/ptrace.h>
32 #include <linux/mman.h>
33 #include <linux/mm.h>
34 #include <linux/swap.h>
35 #include <linux/stddef.h>
36 #include <linux/vmalloc.h>
37 #include <linux/init.h>
38 #include <linux/pci.h>
39 #include <linux/hardirq.h>
40
41 #include <asm/pgalloc.h>
42 #include <asm/io.h>
43 #include <asm/mmu_context.h>
44 #include <asm/pgtable.h>
45 #include <asm/mmu.h>
46 #include <asm/uaccess.h>
47 #include <asm/smp.h>
48
map_page(unsigned long va,unsigned long pa,pgprot_t prot)49 static int map_page(unsigned long va, unsigned long pa, pgprot_t prot)
50 {
51 pgd_t *pge;
52 pud_t *pue;
53 pmd_t *pme;
54 pte_t *pte;
55 int err = -ENOMEM;
56
57 /* Use upper 10 bits of VA to index the first level map */
58 pge = pgd_offset_k(va);
59 pue = pud_offset(pge, va);
60 pme = pmd_offset(pue, va);
61
62 /* Use middle 10 bits of VA to index the second-level map */
63 pte = pte_alloc_kernel(pme, va);
64 if (pte != 0) {
65 err = 0;
66 set_pte(pte, mk_pte_phys(pa & PAGE_MASK, prot));
67 }
68
69 return err;
70 }
71
72 /*
73 * This function will allocate the requested contiguous pages and
74 * map them into the kernel's vmalloc() space. This is done so we
75 * get unique mapping for these pages, outside of the kernel's 1:1
76 * virtual:physical mapping. This is necessary so we can cover large
77 * portions of the kernel with single large page TLB entries, and
78 * still get unique uncached pages for consistent DMA.
79 */
consistent_alloc(gfp_t gfp,size_t size,dma_addr_t * dma_handle)80 void *consistent_alloc(gfp_t gfp, size_t size, dma_addr_t *dma_handle)
81 {
82 struct vm_struct *area;
83 unsigned long page, va, pa;
84 void *ret;
85 int order, err, i;
86
87 if (in_interrupt())
88 BUG();
89
90 /* only allocate page size areas */
91 size = PAGE_ALIGN(size);
92 order = get_order(size);
93
94 page = __get_free_pages(gfp, order);
95 if (!page) {
96 BUG();
97 return NULL;
98 }
99
100 /* allocate some common virtual space to map the new pages */
101 area = get_vm_area(size, VM_ALLOC);
102 if (area == 0) {
103 free_pages(page, order);
104 return NULL;
105 }
106 va = VMALLOC_VMADDR(area->addr);
107 ret = (void *) va;
108
109 /* this gives us the real physical address of the first page */
110 *dma_handle = pa = virt_to_bus((void *) page);
111
112 /* set refcount=1 on all pages in an order>0 allocation so that vfree() will actually free
113 * all pages that were allocated.
114 */
115 if (order > 0) {
116 struct page *rpage = virt_to_page(page);
117 split_page(rpage, order);
118 }
119
120 err = 0;
121 for (i = 0; i < size && err == 0; i += PAGE_SIZE)
122 err = map_page(va + i, pa + i, PAGE_KERNEL_NOCACHE);
123
124 if (err) {
125 vfree((void *) va);
126 return NULL;
127 }
128
129 /* we need to ensure that there are no cachelines in use, or worse dirty in this area
130 * - can't do until after virtual address mappings are created
131 */
132 frv_cache_invalidate(va, va + size);
133
134 return ret;
135 }
136
137 /*
138 * free page(s) as defined by the above mapping.
139 */
consistent_free(void * vaddr)140 void consistent_free(void *vaddr)
141 {
142 if (in_interrupt())
143 BUG();
144 vfree(vaddr);
145 }
146
147 /*
148 * make an area consistent.
149 */
consistent_sync(void * vaddr,size_t size,int direction)150 void consistent_sync(void *vaddr, size_t size, int direction)
151 {
152 unsigned long start = (unsigned long) vaddr;
153 unsigned long end = start + size;
154
155 switch (direction) {
156 case PCI_DMA_NONE:
157 BUG();
158 case PCI_DMA_FROMDEVICE: /* invalidate only */
159 frv_cache_invalidate(start, end);
160 break;
161 case PCI_DMA_TODEVICE: /* writeback only */
162 frv_dcache_writeback(start, end);
163 break;
164 case PCI_DMA_BIDIRECTIONAL: /* writeback and invalidate */
165 frv_dcache_writeback(start, end);
166 break;
167 }
168 }
169
170 /*
171 * consistent_sync_page make a page are consistent. identical
172 * to consistent_sync, but takes a struct page instead of a virtual address
173 */
174
consistent_sync_page(struct page * page,unsigned long offset,size_t size,int direction)175 void consistent_sync_page(struct page *page, unsigned long offset,
176 size_t size, int direction)
177 {
178 void *start;
179
180 start = page_address(page) + offset;
181 consistent_sync(start, size, direction);
182 }
183