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Dan Williams9bc89cd2007-01-02 11:10:44 -07001/*
2 * xor offload engine api
3 *
4 * Copyright © 2006, Intel Corporation.
5 *
6 * Dan Williams <dan.j.williams@intel.com>
7 *
8 * with architecture considerations by:
9 * Neil Brown <neilb@suse.de>
10 * Jeff Garzik <jeff@garzik.org>
11 *
12 * This program is free software; you can redistribute it and/or modify it
13 * under the terms and conditions of the GNU General Public License,
14 * version 2, as published by the Free Software Foundation.
15 *
16 * This program is distributed in the hope it will be useful, but WITHOUT
17 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
18 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
19 * more details.
20 *
21 * You should have received a copy of the GNU General Public License along with
22 * this program; if not, write to the Free Software Foundation, Inc.,
23 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
24 *
25 */
26#include <linux/kernel.h>
27#include <linux/interrupt.h>
28#include <linux/mm.h>
29#include <linux/dma-mapping.h>
30#include <linux/raid/xor.h>
31#include <linux/async_tx.h>
32
Dan Williams06164f32009-03-25 09:13:25 -070033/* do_async_xor - dma map the pages and perform the xor with an engine */
34static __async_inline struct dma_async_tx_descriptor *
Dan Williams1e55db22008-07-16 19:44:56 -070035do_async_xor(struct dma_chan *chan, struct page *dest, struct page **src_list,
36 unsigned int offset, int src_cnt, size_t len,
37 enum async_tx_flags flags,
38 struct dma_async_tx_descriptor *depend_tx,
39 dma_async_tx_callback cb_fn, void *cb_param)
Dan Williams9bc89cd2007-01-02 11:10:44 -070040{
Dan Williams1e55db22008-07-16 19:44:56 -070041 struct dma_device *dma = chan->device;
Dan Williams00367312008-02-02 19:49:57 -070042 dma_addr_t *dma_src = (dma_addr_t *) src_list;
Dan Williams1e55db22008-07-16 19:44:56 -070043 struct dma_async_tx_descriptor *tx = NULL;
44 int src_off = 0;
Dan Williams9bc89cd2007-01-02 11:10:44 -070045 int i;
Dan Williams1e55db22008-07-16 19:44:56 -070046 dma_async_tx_callback _cb_fn;
47 void *_cb_param;
48 enum async_tx_flags async_flags;
49 enum dma_ctrl_flags dma_flags;
50 int xor_src_cnt;
51 dma_addr_t dma_dest;
Dan Williams9bc89cd2007-01-02 11:10:44 -070052
Dan Williamsa06d5682008-12-08 13:46:00 -070053 /* map the dest bidrectional in case it is re-used as a source */
54 dma_dest = dma_map_page(dma->dev, dest, offset, len, DMA_BIDIRECTIONAL);
55 for (i = 0; i < src_cnt; i++) {
56 /* only map the dest once */
57 if (unlikely(src_list[i] == dest)) {
58 dma_src[i] = dma_dest;
59 continue;
60 }
Dan Williams1e55db22008-07-16 19:44:56 -070061 dma_src[i] = dma_map_page(dma->dev, src_list[i], offset,
Dan Williams00367312008-02-02 19:49:57 -070062 len, DMA_TO_DEVICE);
Dan Williamsa06d5682008-12-08 13:46:00 -070063 }
Dan Williams00367312008-02-02 19:49:57 -070064
Dan Williams1e55db22008-07-16 19:44:56 -070065 while (src_cnt) {
66 async_flags = flags;
67 dma_flags = 0;
68 xor_src_cnt = min(src_cnt, dma->max_xor);
69 /* if we are submitting additional xors, leave the chain open,
70 * clear the callback parameters, and leave the destination
71 * buffer mapped
72 */
73 if (src_cnt > xor_src_cnt) {
74 async_flags &= ~ASYNC_TX_ACK;
75 dma_flags = DMA_COMPL_SKIP_DEST_UNMAP;
76 _cb_fn = NULL;
77 _cb_param = NULL;
78 } else {
79 _cb_fn = cb_fn;
80 _cb_param = cb_param;
81 }
82 if (_cb_fn)
83 dma_flags |= DMA_PREP_INTERRUPT;
84
85 /* Since we have clobbered the src_list we are committed
86 * to doing this asynchronously. Drivers force forward progress
87 * in case they can not provide a descriptor
88 */
89 tx = dma->device_prep_dma_xor(chan, dma_dest, &dma_src[src_off],
90 xor_src_cnt, len, dma_flags);
91
Dan Williams669ab0b2008-07-17 17:59:55 -070092 if (unlikely(!tx))
93 async_tx_quiesce(&depend_tx);
Dan Williams00367312008-02-02 19:49:57 -070094
Dan Williams1e55db22008-07-16 19:44:56 -070095 /* spin wait for the preceeding transactions to complete */
Dan Williams669ab0b2008-07-17 17:59:55 -070096 while (unlikely(!tx)) {
97 dma_async_issue_pending(chan);
Dan Williams1e55db22008-07-16 19:44:56 -070098 tx = dma->device_prep_dma_xor(chan, dma_dest,
99 &dma_src[src_off],
100 xor_src_cnt, len,
101 dma_flags);
Dan Williams669ab0b2008-07-17 17:59:55 -0700102 }
Dan Williams9bc89cd2007-01-02 11:10:44 -0700103
Dan Williams1e55db22008-07-16 19:44:56 -0700104 async_tx_submit(chan, tx, async_flags, depend_tx, _cb_fn,
105 _cb_param);
106
107 depend_tx = tx;
108 flags |= ASYNC_TX_DEP_ACK;
109
110 if (src_cnt > xor_src_cnt) {
111 /* drop completed sources */
112 src_cnt -= xor_src_cnt;
113 src_off += xor_src_cnt;
114
115 /* use the intermediate result a source */
116 dma_src[--src_off] = dma_dest;
117 src_cnt++;
118 } else
119 break;
120 }
Dan Williams00367312008-02-02 19:49:57 -0700121
122 return tx;
Dan Williams9bc89cd2007-01-02 11:10:44 -0700123}
124
125static void
126do_sync_xor(struct page *dest, struct page **src_list, unsigned int offset,
Dan Williams1e55db22008-07-16 19:44:56 -0700127 int src_cnt, size_t len, enum async_tx_flags flags,
Dan Williams1e55db22008-07-16 19:44:56 -0700128 dma_async_tx_callback cb_fn, void *cb_param)
Dan Williams9bc89cd2007-01-02 11:10:44 -0700129{
Dan Williams9bc89cd2007-01-02 11:10:44 -0700130 int i;
Dan Williams1e55db22008-07-16 19:44:56 -0700131 int xor_src_cnt;
132 int src_off = 0;
133 void *dest_buf;
134 void **srcs = (void **) src_list;
Dan Williams9bc89cd2007-01-02 11:10:44 -0700135
136 /* reuse the 'src_list' array to convert to buffer pointers */
137 for (i = 0; i < src_cnt; i++)
Dan Williams1e55db22008-07-16 19:44:56 -0700138 srcs[i] = page_address(src_list[i]) + offset;
Dan Williams9bc89cd2007-01-02 11:10:44 -0700139
140 /* set destination address */
Dan Williams1e55db22008-07-16 19:44:56 -0700141 dest_buf = page_address(dest) + offset;
Dan Williams9bc89cd2007-01-02 11:10:44 -0700142
143 if (flags & ASYNC_TX_XOR_ZERO_DST)
Dan Williams1e55db22008-07-16 19:44:56 -0700144 memset(dest_buf, 0, len);
Dan Williams9bc89cd2007-01-02 11:10:44 -0700145
Dan Williams1e55db22008-07-16 19:44:56 -0700146 while (src_cnt > 0) {
147 /* process up to 'MAX_XOR_BLOCKS' sources */
148 xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS);
149 xor_blocks(xor_src_cnt, len, dest_buf, &srcs[src_off]);
150
151 /* drop completed sources */
152 src_cnt -= xor_src_cnt;
153 src_off += xor_src_cnt;
154 }
Dan Williams9bc89cd2007-01-02 11:10:44 -0700155
Dan Williams3dce0172008-07-17 17:59:55 -0700156 async_tx_sync_epilog(cb_fn, cb_param);
Dan Williams9bc89cd2007-01-02 11:10:44 -0700157}
158
159/**
160 * async_xor - attempt to xor a set of blocks with a dma engine.
161 * xor_blocks always uses the dest as a source so the ASYNC_TX_XOR_ZERO_DST
162 * flag must be set to not include dest data in the calculation. The
163 * assumption with dma eninges is that they only use the destination
164 * buffer as a source when it is explicity specified in the source list.
165 * @dest: destination page
166 * @src_list: array of source pages (if the dest is also a source it must be
167 * at index zero). The contents of this array may be overwritten.
168 * @offset: offset in pages to start transaction
169 * @src_cnt: number of source pages
170 * @len: length in bytes
171 * @flags: ASYNC_TX_XOR_ZERO_DST, ASYNC_TX_XOR_DROP_DEST,
Dan Williamsd909b342008-02-02 19:30:14 -0700172 * ASYNC_TX_ACK, ASYNC_TX_DEP_ACK
Dan Williams9bc89cd2007-01-02 11:10:44 -0700173 * @depend_tx: xor depends on the result of this transaction.
174 * @cb_fn: function to call when the xor completes
175 * @cb_param: parameter to pass to the callback routine
176 */
177struct dma_async_tx_descriptor *
178async_xor(struct page *dest, struct page **src_list, unsigned int offset,
179 int src_cnt, size_t len, enum async_tx_flags flags,
180 struct dma_async_tx_descriptor *depend_tx,
181 dma_async_tx_callback cb_fn, void *cb_param)
182{
Dan Williams47437b22008-02-02 19:49:59 -0700183 struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_XOR,
184 &dest, 1, src_list,
185 src_cnt, len);
Dan Williams9bc89cd2007-01-02 11:10:44 -0700186 BUG_ON(src_cnt <= 1);
187
Dan Williams1e55db22008-07-16 19:44:56 -0700188 if (chan) {
189 /* run the xor asynchronously */
190 pr_debug("%s (async): len: %zu\n", __func__, len);
Dan Williams9bc89cd2007-01-02 11:10:44 -0700191
Dan Williams1e55db22008-07-16 19:44:56 -0700192 return do_async_xor(chan, dest, src_list, offset, src_cnt, len,
193 flags, depend_tx, cb_fn, cb_param);
194 } else {
195 /* run the xor synchronously */
196 pr_debug("%s (sync): len: %zu\n", __func__, len);
Dan Williams9bc89cd2007-01-02 11:10:44 -0700197
Dan Williams1e55db22008-07-16 19:44:56 -0700198 /* in the sync case the dest is an implied source
199 * (assumes the dest is the first source)
200 */
201 if (flags & ASYNC_TX_XOR_DROP_DST) {
202 src_cnt--;
203 src_list++;
Dan Williams9bc89cd2007-01-02 11:10:44 -0700204 }
205
Dan Williams1e55db22008-07-16 19:44:56 -0700206 /* wait for any prerequisite operations */
Dan Williamsd2c52b72008-07-17 17:59:55 -0700207 async_tx_quiesce(&depend_tx);
Dan Williams9bc89cd2007-01-02 11:10:44 -0700208
Dan Williams1e55db22008-07-16 19:44:56 -0700209 do_sync_xor(dest, src_list, offset, src_cnt, len,
Dan Williams3dce0172008-07-17 17:59:55 -0700210 flags, cb_fn, cb_param);
Dan Williams1e55db22008-07-16 19:44:56 -0700211
212 return NULL;
213 }
Dan Williams9bc89cd2007-01-02 11:10:44 -0700214}
215EXPORT_SYMBOL_GPL(async_xor);
216
217static int page_is_zero(struct page *p, unsigned int offset, size_t len)
218{
219 char *a = page_address(p) + offset;
220 return ((*(u32 *) a) == 0 &&
221 memcmp(a, a + 4, len - 4) == 0);
222}
223
224/**
225 * async_xor_zero_sum - attempt a xor parity check with a dma engine.
226 * @dest: destination page used if the xor is performed synchronously
227 * @src_list: array of source pages. The dest page must be listed as a source
228 * at index zero. The contents of this array may be overwritten.
229 * @offset: offset in pages to start transaction
230 * @src_cnt: number of source pages
231 * @len: length in bytes
232 * @result: 0 if sum == 0 else non-zero
Dan Williamsd909b342008-02-02 19:30:14 -0700233 * @flags: ASYNC_TX_ACK, ASYNC_TX_DEP_ACK
Dan Williams9bc89cd2007-01-02 11:10:44 -0700234 * @depend_tx: xor depends on the result of this transaction.
235 * @cb_fn: function to call when the xor completes
236 * @cb_param: parameter to pass to the callback routine
237 */
238struct dma_async_tx_descriptor *
239async_xor_zero_sum(struct page *dest, struct page **src_list,
240 unsigned int offset, int src_cnt, size_t len,
241 u32 *result, enum async_tx_flags flags,
242 struct dma_async_tx_descriptor *depend_tx,
243 dma_async_tx_callback cb_fn, void *cb_param)
244{
Dan Williams47437b22008-02-02 19:49:59 -0700245 struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_ZERO_SUM,
246 &dest, 1, src_list,
247 src_cnt, len);
Dan Williams9bc89cd2007-01-02 11:10:44 -0700248 struct dma_device *device = chan ? chan->device : NULL;
Dan Williams00367312008-02-02 19:49:57 -0700249 struct dma_async_tx_descriptor *tx = NULL;
Dan Williams9bc89cd2007-01-02 11:10:44 -0700250
251 BUG_ON(src_cnt <= 1);
252
Dan Williams8d8002f2008-03-18 21:23:59 -0700253 if (device && src_cnt <= device->max_xor) {
Dan Williams00367312008-02-02 19:49:57 -0700254 dma_addr_t *dma_src = (dma_addr_t *) src_list;
Dan Williamsd4c56f92008-02-02 19:49:58 -0700255 unsigned long dma_prep_flags = cb_fn ? DMA_PREP_INTERRUPT : 0;
Dan Williams00367312008-02-02 19:49:57 -0700256 int i;
Dan Williams9bc89cd2007-01-02 11:10:44 -0700257
Dan Williams3280ab3e2008-03-13 17:45:28 -0700258 pr_debug("%s: (async) len: %zu\n", __func__, len);
Dan Williams9bc89cd2007-01-02 11:10:44 -0700259
Dan Williams00367312008-02-02 19:49:57 -0700260 for (i = 0; i < src_cnt; i++)
261 dma_src[i] = dma_map_page(device->dev, src_list[i],
262 offset, len, DMA_TO_DEVICE);
263
264 tx = device->device_prep_dma_zero_sum(chan, dma_src, src_cnt,
265 len, result,
Dan Williamsd4c56f92008-02-02 19:49:58 -0700266 dma_prep_flags);
Dan Williams669ab0b2008-07-17 17:59:55 -0700267 if (unlikely(!tx)) {
268 async_tx_quiesce(&depend_tx);
Dan Williams00367312008-02-02 19:49:57 -0700269
Dan Williamse34a8ae2008-08-05 10:22:05 -0700270 while (!tx) {
Dan Williams669ab0b2008-07-17 17:59:55 -0700271 dma_async_issue_pending(chan);
Dan Williams00367312008-02-02 19:49:57 -0700272 tx = device->device_prep_dma_zero_sum(chan,
273 dma_src, src_cnt, len, result,
Dan Williamsd4c56f92008-02-02 19:49:58 -0700274 dma_prep_flags);
Dan Williamse34a8ae2008-08-05 10:22:05 -0700275 }
Dan Williams9bc89cd2007-01-02 11:10:44 -0700276 }
277
278 async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param);
279 } else {
280 unsigned long xor_flags = flags;
281
Dan Williams3280ab3e2008-03-13 17:45:28 -0700282 pr_debug("%s: (sync) len: %zu\n", __func__, len);
Dan Williams9bc89cd2007-01-02 11:10:44 -0700283
284 xor_flags |= ASYNC_TX_XOR_DROP_DST;
285 xor_flags &= ~ASYNC_TX_ACK;
286
287 tx = async_xor(dest, src_list, offset, src_cnt, len, xor_flags,
288 depend_tx, NULL, NULL);
289
Dan Williamsd2c52b72008-07-17 17:59:55 -0700290 async_tx_quiesce(&tx);
Dan Williams9bc89cd2007-01-02 11:10:44 -0700291
292 *result = page_is_zero(dest, offset, len) ? 0 : 1;
293
Dan Williams3dce0172008-07-17 17:59:55 -0700294 async_tx_sync_epilog(cb_fn, cb_param);
Dan Williams9bc89cd2007-01-02 11:10:44 -0700295 }
296
297 return tx;
298}
299EXPORT_SYMBOL_GPL(async_xor_zero_sum);
300
301static int __init async_xor_init(void)
302{
Dan Williamsdaf42192009-07-01 16:12:53 -0700303 #ifdef CONFIG_ASYNC_TX_DMA
Dan Williams00367312008-02-02 19:49:57 -0700304 /* To conserve stack space the input src_list (array of page pointers)
305 * is reused to hold the array of dma addresses passed to the driver.
306 * This conversion is only possible when dma_addr_t is less than the
307 * the size of a pointer. HIGHMEM64G is known to violate this
308 * assumption.
309 */
310 BUILD_BUG_ON(sizeof(dma_addr_t) > sizeof(struct page *));
311 #endif
312
Dan Williams9bc89cd2007-01-02 11:10:44 -0700313 return 0;
314}
315
316static void __exit async_xor_exit(void)
317{
318 do { } while (0);
319}
320
321module_init(async_xor_init);
322module_exit(async_xor_exit);
323
324MODULE_AUTHOR("Intel Corporation");
325MODULE_DESCRIPTION("asynchronous xor/xor-zero-sum api");
326MODULE_LICENSE("GPL");