Merge git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86
[linux-2.6] / drivers / ieee1394 / dma.c
1 /*
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
10 #include <linux/mm.h>
11 #include <linux/module.h>
12 #include <linux/pci.h>
13 #include <linux/slab.h>
14 #include <linux/vmalloc.h>
15 #include <linux/scatterlist.h>
16
17 #include "dma.h"
18
19 /* dma_prog_region */
20
21 void 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
29 int dma_prog_region_alloc(struct dma_prog_region *prog, unsigned long n_bytes,
30                           struct pci_dev *dev)
31 {
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) {
39                 printk(KERN_ERR
40                        "dma_prog_region_alloc: pci_alloc_consistent() failed\n");
41                 dma_prog_region_free(prog);
42                 return -ENOMEM;
43         }
44
45         prog->dev = dev;
46
47         return 0;
48 }
49
50 void dma_prog_region_free(struct dma_prog_region *prog)
51 {
52         if (prog->kvirt) {
53                 pci_free_consistent(prog->dev, prog->n_pages << PAGE_SHIFT,
54                                     prog->kvirt, prog->bus_addr);
55         }
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
65 /**
66  * dma_region_init - clear out all fields but do not allocate anything
67  */
68 void 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
77 /**
78  * dma_region_alloc - allocate the buffer and map it to the IOMMU
79  */
80 int dma_region_alloc(struct dma_region *dma, unsigned long n_bytes,
81                      struct pci_dev *dev, int direction)
82 {
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         sg_init_table(dma->sglist, dma->n_pages);
107
108         /* fill scatter/gather list with pages */
109         for (i = 0; i < dma->n_pages; i++) {
110                 unsigned long va =
111                     (unsigned long)dma->kvirt + (i << PAGE_SHIFT);
112
113                 sg_set_page(&dma->sglist[i], vmalloc_to_page((void *)va),
114                                 PAGE_SIZE, 0);
115         }
116
117         /* map sglist to the IOMMU */
118         dma->n_dma_pages =
119             pci_map_sg(dev, dma->sglist, dma->n_pages, direction);
120
121         if (dma->n_dma_pages == 0) {
122                 printk(KERN_ERR "dma_region_alloc: pci_map_sg() failed\n");
123                 goto err;
124         }
125
126         dma->dev = dev;
127         dma->direction = direction;
128
129         return 0;
130
131       err:
132         dma_region_free(dma);
133         return -ENOMEM;
134 }
135
136 /**
137  * dma_region_free - unmap and free the buffer
138  */
139 void dma_region_free(struct dma_region *dma)
140 {
141         if (dma->n_dma_pages) {
142                 pci_unmap_sg(dma->dev, dma->sglist, dma->n_pages,
143                              dma->direction);
144                 dma->n_dma_pages = 0;
145                 dma->dev = NULL;
146         }
147
148         vfree(dma->sglist);
149         dma->sglist = NULL;
150
151         vfree(dma->kvirt);
152         dma->kvirt = NULL;
153         dma->n_pages = 0;
154 }
155
156 /* find the scatterlist index and remaining offset corresponding to a
157    given offset from the beginning of the buffer */
158 static inline int dma_region_find(struct dma_region *dma, unsigned long offset,
159                                   unsigned int start, unsigned long *rem)
160 {
161         int i;
162         unsigned long off = offset;
163
164         for (i = start; i < dma->n_dma_pages; i++) {
165                 if (off < sg_dma_len(&dma->sglist[i])) {
166                         *rem = off;
167                         break;
168                 }
169
170                 off -= sg_dma_len(&dma->sglist[i]);
171         }
172
173         BUG_ON(i >= dma->n_dma_pages);
174
175         return i;
176 }
177
178 /**
179  * dma_region_offset_to_bus - get bus address of an offset within a DMA region
180  *
181  * Returns the DMA bus address of the byte with the given @offset relative to
182  * the beginning of the @dma.
183  */
184 dma_addr_t dma_region_offset_to_bus(struct dma_region * dma,
185                                     unsigned long offset)
186 {
187         unsigned long rem = 0;
188
189         struct scatterlist *sg =
190             &dma->sglist[dma_region_find(dma, offset, 0, &rem)];
191         return sg_dma_address(sg) + rem;
192 }
193
194 /**
195  * dma_region_sync_for_cpu - sync the CPU's view of the buffer
196  */
197 void dma_region_sync_for_cpu(struct dma_region *dma, unsigned long offset,
198                              unsigned long len)
199 {
200         int first, last;
201         unsigned long rem = 0;
202
203         if (!len)
204                 len = 1;
205
206         first = dma_region_find(dma, offset, 0, &rem);
207         last = dma_region_find(dma, rem + len - 1, first, &rem);
208
209         pci_dma_sync_sg_for_cpu(dma->dev, &dma->sglist[first], last - first + 1,
210                                 dma->direction);
211 }
212
213 /**
214  * dma_region_sync_for_device - sync the IO bus' view of the buffer
215  */
216 void dma_region_sync_for_device(struct dma_region *dma, unsigned long offset,
217                                 unsigned long len)
218 {
219         int first, last;
220         unsigned long rem = 0;
221
222         if (!len)
223                 len = 1;
224
225         first = dma_region_find(dma, offset, 0, &rem);
226         last = dma_region_find(dma, rem + len - 1, first, &rem);
227
228         pci_dma_sync_sg_for_device(dma->dev, &dma->sglist[first],
229                                    last - first + 1, dma->direction);
230 }
231
232 #ifdef CONFIG_MMU
233
234 /* nopage() handler for mmap access */
235
236 static struct page *dma_region_pagefault(struct vm_area_struct *area,
237                                          unsigned long address, int *type)
238 {
239         unsigned long offset;
240         unsigned long kernel_virt_addr;
241         struct page *ret = NOPAGE_SIGBUS;
242
243         struct dma_region *dma = (struct dma_region *)area->vm_private_data;
244
245         if (!dma->kvirt)
246                 goto out;
247
248         if ((address < (unsigned long)area->vm_start) ||
249             (address >
250              (unsigned long)area->vm_start + (dma->n_pages << PAGE_SHIFT)))
251                 goto out;
252
253         if (type)
254                 *type = VM_FAULT_MINOR;
255         offset = address - area->vm_start;
256         kernel_virt_addr = (unsigned long)dma->kvirt + offset;
257         ret = vmalloc_to_page((void *)kernel_virt_addr);
258         get_page(ret);
259       out:
260         return ret;
261 }
262
263 static struct vm_operations_struct dma_region_vm_ops = {
264         .nopage = dma_region_pagefault,
265 };
266
267 /**
268  * dma_region_mmap - map the buffer into a user space process
269  */
270 int dma_region_mmap(struct dma_region *dma, struct file *file,
271                     struct vm_area_struct *vma)
272 {
273         unsigned long size;
274
275         if (!dma->kvirt)
276                 return -EINVAL;
277
278         /* must be page-aligned */
279         if (vma->vm_pgoff != 0)
280                 return -EINVAL;
281
282         /* check the length */
283         size = vma->vm_end - vma->vm_start;
284         if (size > (dma->n_pages << PAGE_SHIFT))
285                 return -EINVAL;
286
287         vma->vm_ops = &dma_region_vm_ops;
288         vma->vm_private_data = dma;
289         vma->vm_file = file;
290         vma->vm_flags |= VM_RESERVED;
291
292         return 0;
293 }
294
295 #else                           /* CONFIG_MMU */
296
297 int dma_region_mmap(struct dma_region *dma, struct file *file,
298                     struct vm_area_struct *vma)
299 {
300         return -EINVAL;
301 }
302
303 #endif                          /* CONFIG_MMU */