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 #include <linux/gfp.h>
41
42 #include <asm/pgalloc.h>
43 #include <asm/io.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
map_page(unsigned long va,unsigned long pa,pgprot_t prot)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 /* Use upper 10 bits of VA to index the first level map */
59 pge = pgd_offset_k(va);
60 pue = pud_offset(pge, va);
61 pme = pmd_offset(pue, va);
62
63 /* Use middle 10 bits of VA to index the second-level map */
64 pte = pte_alloc_kernel(pme, va);
65 if (pte != 0) {
66 err = 0;
67 set_pte(pte, mk_pte_phys(pa & PAGE_MASK, prot));
68 }
69
70 return err;
71 }
72
73 /*
74 * This function will allocate the requested contiguous pages and
75 * map them into the kernel's vmalloc() space. This is done so we
76 * get unique mapping for these pages, outside of the kernel's 1:1
77 * virtual:physical mapping. This is necessary so we can cover large
78 * portions of the kernel with single large page TLB entries, and
79 * still get unique uncached pages for consistent DMA.
80 */
consistent_alloc(gfp_t gfp,size_t size,dma_addr_t * dma_handle)81 void *consistent_alloc(gfp_t gfp, size_t size, dma_addr_t *dma_handle)
82 {
83 struct vm_struct *area;
84 unsigned long page, va, pa;
85 void *ret;
86 int order, err, i;
87
88 if (in_interrupt())
89 BUG();
90
91 /* only allocate page size areas */
92 size = PAGE_ALIGN(size);
93 order = get_order(size);
94
95 page = __get_free_pages(gfp, order);
96 if (!page) {
97 BUG();
98 return NULL;
99 }
100
101 /* allocate some common virtual space to map the new pages */
102 area = get_vm_area(size, VM_ALLOC);
103 if (area == 0) {
104 free_pages(page, order);
105 return NULL;
106 }
107 va = VMALLOC_VMADDR(area->addr);
108 ret = (void *) va;
109
110 /* this gives us the real physical address of the first page */
111 *dma_handle = pa = virt_to_bus((void *) page);
112
113 /* set refcount=1 on all pages in an order>0 allocation so that vfree() will actually free
114 * all pages that were allocated.
115 */
116 if (order > 0) {
117 struct page *rpage = virt_to_page(page);
118 split_page(rpage, order);
119 }
120
121 err = 0;
122 for (i = 0; i < size && err == 0; i += PAGE_SIZE)
123 err = map_page(va + i, pa + i, PAGE_KERNEL_NOCACHE);
124
125 if (err) {
126 vfree((void *) va);
127 return NULL;
128 }
129
130 /* we need to ensure that there are no cachelines in use, or worse dirty in this area
131 * - can't do until after virtual address mappings are created
132 */
133 frv_cache_invalidate(va, va + size);
134
135 return ret;
136 }
137
138 /*
139 * free page(s) as defined by the above mapping.
140 */
consistent_free(void * vaddr)141 void consistent_free(void *vaddr)
142 {
143 if (in_interrupt())
144 BUG();
145 vfree(vaddr);
146 }
147
148 /*
149 * make an area consistent.
150 */
consistent_sync(void * vaddr,size_t size,int direction)151 void consistent_sync(void *vaddr, size_t size, int direction)
152 {
153 unsigned long start = (unsigned long) vaddr;
154 unsigned long end = start + size;
155
156 switch (direction) {
157 case PCI_DMA_NONE:
158 BUG();
159 case PCI_DMA_FROMDEVICE: /* invalidate only */
160 frv_cache_invalidate(start, end);
161 break;
162 case PCI_DMA_TODEVICE: /* writeback only */
163 frv_dcache_writeback(start, end);
164 break;
165 case PCI_DMA_BIDIRECTIONAL: /* writeback and invalidate */
166 frv_dcache_writeback(start, end);
167 break;
168 }
169 }
170
171 /*
172 * consistent_sync_page make a page are consistent. identical
173 * to consistent_sync, but takes a struct page instead of a virtual address
174 */
175
consistent_sync_page(struct page * page,unsigned long offset,size_t size,int direction)176 void consistent_sync_page(struct page *page, unsigned long offset,
177 size_t size, int direction)
178 {
179 void *start;
180
181 start = page_address(page) + offset;
182 consistent_sync(start, size, direction);
183 }
184