blob: 45d6055819227367fb318e472b1ee2de990b458f [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * DMA region bookkeeping routines
3 *
4 * Copyright (C) 2002 Maas Digital LLC
5 *
6 * This code is licensed under the GPL. See the file COPYING in the root
7 * directory of the kernel sources for details.
8 */
9
Linus Torvalds1da177e2005-04-16 15:20:36 -070010#include <linux/mm.h>
Stefan Richterde4394f2006-07-03 12:02:29 -040011#include <linux/module.h>
12#include <linux/pci.h>
13#include <linux/slab.h>
14#include <linux/vmalloc.h>
15#include <asm/scatterlist.h>
16
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include "dma.h"
18
19/* dma_prog_region */
20
21void dma_prog_region_init(struct dma_prog_region *prog)
22{
23 prog->kvirt = NULL;
24 prog->dev = NULL;
25 prog->n_pages = 0;
26 prog->bus_addr = 0;
27}
28
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -050029int dma_prog_region_alloc(struct dma_prog_region *prog, unsigned long n_bytes,
30 struct pci_dev *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -070031{
32 /* round up to page size */
33 n_bytes = PAGE_ALIGN(n_bytes);
34
35 prog->n_pages = n_bytes >> PAGE_SHIFT;
36
37 prog->kvirt = pci_alloc_consistent(dev, n_bytes, &prog->bus_addr);
38 if (!prog->kvirt) {
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -050039 printk(KERN_ERR
40 "dma_prog_region_alloc: pci_alloc_consistent() failed\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 dma_prog_region_free(prog);
42 return -ENOMEM;
43 }
44
45 prog->dev = dev;
46
47 return 0;
48}
49
50void dma_prog_region_free(struct dma_prog_region *prog)
51{
52 if (prog->kvirt) {
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -050053 pci_free_consistent(prog->dev, prog->n_pages << PAGE_SHIFT,
54 prog->kvirt, prog->bus_addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -070055 }
56
57 prog->kvirt = NULL;
58 prog->dev = NULL;
59 prog->n_pages = 0;
60 prog->bus_addr = 0;
61}
62
63/* dma_region */
64
Stefan Richterafd65462007-03-05 03:06:23 +010065/**
66 * dma_region_init - clear out all fields but do not allocate anything
67 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070068void dma_region_init(struct dma_region *dma)
69{
70 dma->kvirt = NULL;
71 dma->dev = NULL;
72 dma->n_pages = 0;
73 dma->n_dma_pages = 0;
74 dma->sglist = NULL;
75}
76
Stefan Richterafd65462007-03-05 03:06:23 +010077/**
78 * dma_region_alloc - allocate the buffer and map it to the IOMMU
79 */
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -050080int dma_region_alloc(struct dma_region *dma, unsigned long n_bytes,
81 struct pci_dev *dev, int direction)
Linus Torvalds1da177e2005-04-16 15:20:36 -070082{
83 unsigned int i;
84
85 /* round up to page size */
86 n_bytes = PAGE_ALIGN(n_bytes);
87
88 dma->n_pages = n_bytes >> PAGE_SHIFT;
89
90 dma->kvirt = vmalloc_32(n_bytes);
91 if (!dma->kvirt) {
92 printk(KERN_ERR "dma_region_alloc: vmalloc_32() failed\n");
93 goto err;
94 }
95
96 /* Clear the ram out, no junk to the user */
97 memset(dma->kvirt, 0, n_bytes);
98
99 /* allocate scatter/gather list */
100 dma->sglist = vmalloc(dma->n_pages * sizeof(*dma->sglist));
101 if (!dma->sglist) {
102 printk(KERN_ERR "dma_region_alloc: vmalloc(sglist) failed\n");
103 goto err;
104 }
105
106 /* just to be safe - this will become unnecessary once sglist->address goes away */
107 memset(dma->sglist, 0, dma->n_pages * sizeof(*dma->sglist));
108
109 /* fill scatter/gather list with pages */
110 for (i = 0; i < dma->n_pages; i++) {
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500111 unsigned long va =
112 (unsigned long)dma->kvirt + (i << PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113
114 dma->sglist[i].page = vmalloc_to_page((void *)va);
115 dma->sglist[i].length = PAGE_SIZE;
116 }
117
118 /* map sglist to the IOMMU */
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500119 dma->n_dma_pages =
120 pci_map_sg(dev, dma->sglist, dma->n_pages, direction);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121
122 if (dma->n_dma_pages == 0) {
123 printk(KERN_ERR "dma_region_alloc: pci_map_sg() failed\n");
124 goto err;
125 }
126
127 dma->dev = dev;
128 dma->direction = direction;
129
130 return 0;
131
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500132 err:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 dma_region_free(dma);
134 return -ENOMEM;
135}
136
Stefan Richterafd65462007-03-05 03:06:23 +0100137/**
138 * dma_region_free - unmap and free the buffer
139 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140void dma_region_free(struct dma_region *dma)
141{
142 if (dma->n_dma_pages) {
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500143 pci_unmap_sg(dma->dev, dma->sglist, dma->n_pages,
144 dma->direction);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 dma->n_dma_pages = 0;
146 dma->dev = NULL;
147 }
148
149 vfree(dma->sglist);
150 dma->sglist = NULL;
151
152 vfree(dma->kvirt);
153 dma->kvirt = NULL;
154 dma->n_pages = 0;
155}
156
157/* find the scatterlist index and remaining offset corresponding to a
158 given offset from the beginning of the buffer */
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500159static inline int dma_region_find(struct dma_region *dma, unsigned long offset,
Ben Collins9bb2bcd2006-06-12 17:52:59 -0400160 unsigned int start, unsigned long *rem)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161{
162 int i;
163 unsigned long off = offset;
164
Ben Collins9bb2bcd2006-06-12 17:52:59 -0400165 for (i = start; i < dma->n_dma_pages; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 if (off < sg_dma_len(&dma->sglist[i])) {
167 *rem = off;
168 break;
169 }
170
171 off -= sg_dma_len(&dma->sglist[i]);
172 }
173
174 BUG_ON(i >= dma->n_dma_pages);
175
176 return i;
177}
178
Stefan Richterafd65462007-03-05 03:06:23 +0100179/**
180 * dma_region_offset_to_bus - get bus address of an offset within a DMA region
181 *
182 * Returns the DMA bus address of the byte with the given @offset relative to
183 * the beginning of the @dma.
184 */
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500185dma_addr_t dma_region_offset_to_bus(struct dma_region * dma,
186 unsigned long offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187{
Ben Collins1934b8b2005-07-09 20:01:23 -0400188 unsigned long rem = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500190 struct scatterlist *sg =
Ben Collins9bb2bcd2006-06-12 17:52:59 -0400191 &dma->sglist[dma_region_find(dma, offset, 0, &rem)];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 return sg_dma_address(sg) + rem;
193}
194
Stefan Richterafd65462007-03-05 03:06:23 +0100195/**
196 * dma_region_sync_for_cpu - sync the CPU's view of the buffer
197 */
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500198void dma_region_sync_for_cpu(struct dma_region *dma, unsigned long offset,
199 unsigned long len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200{
201 int first, last;
Ben Collins9bb2bcd2006-06-12 17:52:59 -0400202 unsigned long rem = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203
204 if (!len)
205 len = 1;
206
Ben Collins9bb2bcd2006-06-12 17:52:59 -0400207 first = dma_region_find(dma, offset, 0, &rem);
208 last = dma_region_find(dma, rem + len - 1, first, &rem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500210 pci_dma_sync_sg_for_cpu(dma->dev, &dma->sglist[first], last - first + 1,
211 dma->direction);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212}
213
Stefan Richterafd65462007-03-05 03:06:23 +0100214/**
215 * dma_region_sync_for_device - sync the IO bus' view of the buffer
216 */
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500217void dma_region_sync_for_device(struct dma_region *dma, unsigned long offset,
218 unsigned long len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219{
220 int first, last;
Ben Collins9bb2bcd2006-06-12 17:52:59 -0400221 unsigned long rem = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222
223 if (!len)
224 len = 1;
225
Ben Collins9bb2bcd2006-06-12 17:52:59 -0400226 first = dma_region_find(dma, offset, 0, &rem);
227 last = dma_region_find(dma, rem + len - 1, first, &rem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500229 pci_dma_sync_sg_for_device(dma->dev, &dma->sglist[first],
230 last - first + 1, dma->direction);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231}
232
233#ifdef CONFIG_MMU
234
235/* nopage() handler for mmap access */
236
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500237static struct page *dma_region_pagefault(struct vm_area_struct *area,
238 unsigned long address, int *type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239{
240 unsigned long offset;
241 unsigned long kernel_virt_addr;
242 struct page *ret = NOPAGE_SIGBUS;
243
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500244 struct dma_region *dma = (struct dma_region *)area->vm_private_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245
246 if (!dma->kvirt)
247 goto out;
248
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500249 if ((address < (unsigned long)area->vm_start) ||
250 (address >
251 (unsigned long)area->vm_start + (dma->n_pages << PAGE_SHIFT)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 goto out;
253
254 if (type)
255 *type = VM_FAULT_MINOR;
256 offset = address - area->vm_start;
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500257 kernel_virt_addr = (unsigned long)dma->kvirt + offset;
258 ret = vmalloc_to_page((void *)kernel_virt_addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 get_page(ret);
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500260 out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 return ret;
262}
263
264static struct vm_operations_struct dma_region_vm_ops = {
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500265 .nopage = dma_region_pagefault,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266};
267
Stefan Richterafd65462007-03-05 03:06:23 +0100268/**
269 * dma_region_mmap - map the buffer into a user space process
270 */
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500271int dma_region_mmap(struct dma_region *dma, struct file *file,
272 struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273{
274 unsigned long size;
275
276 if (!dma->kvirt)
277 return -EINVAL;
278
279 /* must be page-aligned */
280 if (vma->vm_pgoff != 0)
281 return -EINVAL;
282
283 /* check the length */
284 size = vma->vm_end - vma->vm_start;
285 if (size > (dma->n_pages << PAGE_SHIFT))
286 return -EINVAL;
287
288 vma->vm_ops = &dma_region_vm_ops;
289 vma->vm_private_data = dma;
290 vma->vm_file = file;
291 vma->vm_flags |= VM_RESERVED;
292
293 return 0;
294}
295
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500296#else /* CONFIG_MMU */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500298int dma_region_mmap(struct dma_region *dma, struct file *file,
299 struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300{
301 return -EINVAL;
302}
303
Jens-Michael Hoffmann6649e922005-11-22 12:18:28 -0500304#endif /* CONFIG_MMU */