blob: c0a272c7368267ad25bd5185e14d5fa965cb2751 [file] [log] [blame]
Chris Leechde5506e2006-05-23 17:50:37 -07001/*
2 * Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
3 * Portions based on net/core/datagram.c and copyrighted by their authors.
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the Free
7 * Software Foundation; either version 2 of the License, or (at your option)
8 * any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 59
17 * Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 *
19 * The full GNU General Public License is included in this distribution in the
20 * file called COPYING.
21 */
22
23/*
24 * This code allows the net stack to make use of a DMA engine for
25 * skb to iovec copies.
26 */
27
28#include <linux/dmaengine.h>
29#include <linux/pagemap.h>
30#include <net/tcp.h> /* for memcpy_toiovec */
31#include <asm/io.h>
32#include <asm/uaccess.h>
33
Adrian Bunk56e08732006-07-03 19:27:20 -070034static int num_pages_spanned(struct iovec *iov)
Chris Leechde5506e2006-05-23 17:50:37 -070035{
36 return
37 ((PAGE_ALIGN((unsigned long)iov->iov_base + iov->iov_len) -
38 ((unsigned long)iov->iov_base & PAGE_MASK)) >> PAGE_SHIFT);
39}
40
41/*
42 * Pin down all the iovec pages needed for len bytes.
43 * Return a struct dma_pinned_list to keep track of pages pinned down.
44 *
45 * We are allocating a single chunk of memory, and then carving it up into
46 * 3 sections, the latter 2 whose size depends on the number of iovecs and the
47 * total number of pages, respectively.
48 */
49struct dma_pinned_list *dma_pin_iovec_pages(struct iovec *iov, size_t len)
50{
51 struct dma_pinned_list *local_list;
52 struct page **pages;
53 int i;
54 int ret;
55 int nr_iovecs = 0;
56 int iovec_len_used = 0;
57 int iovec_pages_used = 0;
Chris Leechde5506e2006-05-23 17:50:37 -070058
59 /* don't pin down non-user-based iovecs */
60 if (segment_eq(get_fs(), KERNEL_DS))
61 return NULL;
62
63 /* determine how many iovecs/pages there are, up front */
64 do {
65 iovec_len_used += iov[nr_iovecs].iov_len;
66 iovec_pages_used += num_pages_spanned(&iov[nr_iovecs]);
67 nr_iovecs++;
68 } while (iovec_len_used < len);
69
70 /* single kmalloc for pinned list, page_list[], and the page arrays */
71 local_list = kmalloc(sizeof(*local_list)
72 + (nr_iovecs * sizeof (struct dma_page_list))
73 + (iovec_pages_used * sizeof (struct page*)), GFP_KERNEL);
Maciej Sosnowskic2c0b4c2008-11-07 01:46:33 +000074 if (!local_list)
Chris Leechde5506e2006-05-23 17:50:37 -070075 goto out;
Chris Leechde5506e2006-05-23 17:50:37 -070076
77 /* list of pages starts right after the page list array */
78 pages = (struct page **) &local_list->page_list[nr_iovecs];
79
Maciej Sosnowskic2c0b4c2008-11-07 01:46:33 +000080 local_list->nr_iovecs = 0;
81
Chris Leechde5506e2006-05-23 17:50:37 -070082 for (i = 0; i < nr_iovecs; i++) {
83 struct dma_page_list *page_list = &local_list->page_list[i];
84
85 len -= iov[i].iov_len;
86
Maciej Sosnowskic2c0b4c2008-11-07 01:46:33 +000087 if (!access_ok(VERIFY_WRITE, iov[i].iov_base, iov[i].iov_len))
Chris Leechde5506e2006-05-23 17:50:37 -070088 goto unpin;
Chris Leechde5506e2006-05-23 17:50:37 -070089
90 page_list->nr_pages = num_pages_spanned(&iov[i]);
91 page_list->base_address = iov[i].iov_base;
92
93 page_list->pages = pages;
94 pages += page_list->nr_pages;
95
96 /* pin pages down */
97 down_read(&current->mm->mmap_sem);
98 ret = get_user_pages(
99 current,
100 current->mm,
101 (unsigned long) iov[i].iov_base,
102 page_list->nr_pages,
103 1, /* write */
104 0, /* force */
105 page_list->pages,
106 NULL);
107 up_read(&current->mm->mmap_sem);
108
Maciej Sosnowskic2c0b4c2008-11-07 01:46:33 +0000109 if (ret != page_list->nr_pages)
Chris Leechde5506e2006-05-23 17:50:37 -0700110 goto unpin;
Chris Leechde5506e2006-05-23 17:50:37 -0700111
112 local_list->nr_iovecs = i + 1;
113 }
114
115 return local_list;
116
117unpin:
118 dma_unpin_iovec_pages(local_list);
119out:
Maciej Sosnowskic2c0b4c2008-11-07 01:46:33 +0000120 return NULL;
Chris Leechde5506e2006-05-23 17:50:37 -0700121}
122
123void dma_unpin_iovec_pages(struct dma_pinned_list *pinned_list)
124{
125 int i, j;
126
127 if (!pinned_list)
128 return;
129
130 for (i = 0; i < pinned_list->nr_iovecs; i++) {
131 struct dma_page_list *page_list = &pinned_list->page_list[i];
132 for (j = 0; j < page_list->nr_pages; j++) {
133 set_page_dirty_lock(page_list->pages[j]);
134 page_cache_release(page_list->pages[j]);
135 }
136 }
137
138 kfree(pinned_list);
139}
140
Chris Leechde5506e2006-05-23 17:50:37 -0700141
142/*
143 * We have already pinned down the pages we will be using in the iovecs.
144 * Each entry in iov array has corresponding entry in pinned_list->page_list.
145 * Using array indexing to keep iov[] and page_list[] in sync.
146 * Initial elements in iov array's iov->iov_len will be 0 if already copied into
147 * by another call.
148 * iov array length remaining guaranteed to be bigger than len.
149 */
150dma_cookie_t dma_memcpy_to_iovec(struct dma_chan *chan, struct iovec *iov,
151 struct dma_pinned_list *pinned_list, unsigned char *kdata, size_t len)
152{
153 int iov_byte_offset;
154 int copy;
155 dma_cookie_t dma_cookie = 0;
156 int iovec_idx;
157 int page_idx;
158
159 if (!chan)
160 return memcpy_toiovec(iov, kdata, len);
161
Chris Leechde5506e2006-05-23 17:50:37 -0700162 iovec_idx = 0;
163 while (iovec_idx < pinned_list->nr_iovecs) {
164 struct dma_page_list *page_list;
165
166 /* skip already used-up iovecs */
167 while (!iov[iovec_idx].iov_len)
168 iovec_idx++;
169
170 page_list = &pinned_list->page_list[iovec_idx];
171
172 iov_byte_offset = ((unsigned long)iov[iovec_idx].iov_base & ~PAGE_MASK);
173 page_idx = (((unsigned long)iov[iovec_idx].iov_base & PAGE_MASK)
174 - ((unsigned long)page_list->base_address & PAGE_MASK)) >> PAGE_SHIFT;
175
176 /* break up copies to not cross page boundary */
177 while (iov[iovec_idx].iov_len) {
178 copy = min_t(int, PAGE_SIZE - iov_byte_offset, len);
179 copy = min_t(int, copy, iov[iovec_idx].iov_len);
180
181 dma_cookie = dma_async_memcpy_buf_to_pg(chan,
182 page_list->pages[page_idx],
183 iov_byte_offset,
184 kdata,
185 copy);
Dan Williams4b652f02009-09-08 12:02:15 -0700186 /* poll for a descriptor slot */
187 if (unlikely(dma_cookie < 0)) {
188 dma_async_issue_pending(chan);
189 continue;
190 }
Chris Leechde5506e2006-05-23 17:50:37 -0700191
192 len -= copy;
193 iov[iovec_idx].iov_len -= copy;
194 iov[iovec_idx].iov_base += copy;
195
196 if (!len)
197 return dma_cookie;
198
199 kdata += copy;
200 iov_byte_offset = 0;
201 page_idx++;
202 }
203 iovec_idx++;
204 }
205
206 /* really bad if we ever run out of iovecs */
207 BUG();
208 return -EFAULT;
209}
210
211dma_cookie_t dma_memcpy_pg_to_iovec(struct dma_chan *chan, struct iovec *iov,
212 struct dma_pinned_list *pinned_list, struct page *page,
213 unsigned int offset, size_t len)
214{
215 int iov_byte_offset;
216 int copy;
217 dma_cookie_t dma_cookie = 0;
218 int iovec_idx;
219 int page_idx;
220 int err;
221
222 /* this needs as-yet-unimplemented buf-to-buff, so punt. */
223 /* TODO: use dma for this */
224 if (!chan || !pinned_list) {
225 u8 *vaddr = kmap(page);
226 err = memcpy_toiovec(iov, vaddr + offset, len);
227 kunmap(page);
228 return err;
229 }
230
231 iovec_idx = 0;
232 while (iovec_idx < pinned_list->nr_iovecs) {
233 struct dma_page_list *page_list;
234
235 /* skip already used-up iovecs */
236 while (!iov[iovec_idx].iov_len)
237 iovec_idx++;
238
239 page_list = &pinned_list->page_list[iovec_idx];
240
241 iov_byte_offset = ((unsigned long)iov[iovec_idx].iov_base & ~PAGE_MASK);
242 page_idx = (((unsigned long)iov[iovec_idx].iov_base & PAGE_MASK)
243 - ((unsigned long)page_list->base_address & PAGE_MASK)) >> PAGE_SHIFT;
244
245 /* break up copies to not cross page boundary */
246 while (iov[iovec_idx].iov_len) {
247 copy = min_t(int, PAGE_SIZE - iov_byte_offset, len);
248 copy = min_t(int, copy, iov[iovec_idx].iov_len);
249
250 dma_cookie = dma_async_memcpy_pg_to_pg(chan,
251 page_list->pages[page_idx],
252 iov_byte_offset,
253 page,
254 offset,
255 copy);
Dan Williams4b652f02009-09-08 12:02:15 -0700256 /* poll for a descriptor slot */
257 if (unlikely(dma_cookie < 0)) {
258 dma_async_issue_pending(chan);
259 continue;
260 }
Chris Leechde5506e2006-05-23 17:50:37 -0700261
262 len -= copy;
263 iov[iovec_idx].iov_len -= copy;
264 iov[iovec_idx].iov_base += copy;
265
266 if (!len)
267 return dma_cookie;
268
269 offset += copy;
270 iov_byte_offset = 0;
271 page_idx++;
272 }
273 iovec_idx++;
274 }
275
276 /* really bad if we ever run out of iovecs */
277 BUG();
278 return -EFAULT;
279}