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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * xor offload engine api4 *5 * Copyright © 2006, Intel Corporation.6 *7 * Dan Williams <dan.j.williams@intel.com>8 *9 * with architecture considerations by:10 * Neil Brown <neilb@suse.de>11 * Jeff Garzik <jeff@garzik.org>12 */13#include <linux/kernel.h>14#include <linux/interrupt.h>15#include <linux/module.h>16#include <linux/mm.h>17#include <linux/dma-mapping.h>18#include <linux/raid/xor.h>19#include <linux/async_tx.h>20 21/* do_async_xor - dma map the pages and perform the xor with an engine */22static __async_inline struct dma_async_tx_descriptor *23do_async_xor(struct dma_chan *chan, struct dmaengine_unmap_data *unmap,24 struct async_submit_ctl *submit)25{26 struct dma_device *dma = chan->device;27 struct dma_async_tx_descriptor *tx = NULL;28 dma_async_tx_callback cb_fn_orig = submit->cb_fn;29 void *cb_param_orig = submit->cb_param;30 enum async_tx_flags flags_orig = submit->flags;31 enum dma_ctrl_flags dma_flags = 0;32 int src_cnt = unmap->to_cnt;33 int xor_src_cnt;34 dma_addr_t dma_dest = unmap->addr[unmap->to_cnt];35 dma_addr_t *src_list = unmap->addr;36 37 while (src_cnt) {38 dma_addr_t tmp;39 40 submit->flags = flags_orig;41 xor_src_cnt = min(src_cnt, (int)dma->max_xor);42 /* if we are submitting additional xors, leave the chain open43 * and clear the callback parameters44 */45 if (src_cnt > xor_src_cnt) {46 submit->flags &= ~ASYNC_TX_ACK;47 submit->flags |= ASYNC_TX_FENCE;48 submit->cb_fn = NULL;49 submit->cb_param = NULL;50 } else {51 submit->cb_fn = cb_fn_orig;52 submit->cb_param = cb_param_orig;53 }54 if (submit->cb_fn)55 dma_flags |= DMA_PREP_INTERRUPT;56 if (submit->flags & ASYNC_TX_FENCE)57 dma_flags |= DMA_PREP_FENCE;58 59 /* Drivers force forward progress in case they can not provide a60 * descriptor61 */62 tmp = src_list[0];63 if (src_list > unmap->addr)64 src_list[0] = dma_dest;65 tx = dma->device_prep_dma_xor(chan, dma_dest, src_list,66 xor_src_cnt, unmap->len,67 dma_flags);68 69 if (unlikely(!tx))70 async_tx_quiesce(&submit->depend_tx);71 72 /* spin wait for the preceding transactions to complete */73 while (unlikely(!tx)) {74 dma_async_issue_pending(chan);75 tx = dma->device_prep_dma_xor(chan, dma_dest,76 src_list,77 xor_src_cnt, unmap->len,78 dma_flags);79 }80 src_list[0] = tmp;81 82 dma_set_unmap(tx, unmap);83 async_tx_submit(chan, tx, submit);84 submit->depend_tx = tx;85 86 if (src_cnt > xor_src_cnt) {87 /* drop completed sources */88 src_cnt -= xor_src_cnt;89 /* use the intermediate result a source */90 src_cnt++;91 src_list += xor_src_cnt - 1;92 } else93 break;94 }95 96 return tx;97}98 99static void100do_sync_xor_offs(struct page *dest, unsigned int offset,101 struct page **src_list, unsigned int *src_offs,102 int src_cnt, size_t len, struct async_submit_ctl *submit)103{104 int i;105 int xor_src_cnt = 0;106 int src_off = 0;107 void *dest_buf;108 void **srcs;109 110 if (submit->scribble)111 srcs = submit->scribble;112 else113 srcs = (void **) src_list;114 115 /* convert to buffer pointers */116 for (i = 0; i < src_cnt; i++)117 if (src_list[i])118 srcs[xor_src_cnt++] = page_address(src_list[i]) +119 (src_offs ? src_offs[i] : offset);120 src_cnt = xor_src_cnt;121 /* set destination address */122 dest_buf = page_address(dest) + offset;123 124 if (submit->flags & ASYNC_TX_XOR_ZERO_DST)125 memset(dest_buf, 0, len);126 127 while (src_cnt > 0) {128 /* process up to 'MAX_XOR_BLOCKS' sources */129 xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS);130 xor_blocks(xor_src_cnt, len, dest_buf, &srcs[src_off]);131 132 /* drop completed sources */133 src_cnt -= xor_src_cnt;134 src_off += xor_src_cnt;135 }136 137 async_tx_sync_epilog(submit);138}139 140static inline bool141dma_xor_aligned_offsets(struct dma_device *device, unsigned int offset,142 unsigned int *src_offs, int src_cnt, int len)143{144 int i;145 146 if (!is_dma_xor_aligned(device, offset, 0, len))147 return false;148 149 if (!src_offs)150 return true;151 152 for (i = 0; i < src_cnt; i++) {153 if (!is_dma_xor_aligned(device, src_offs[i], 0, len))154 return false;155 }156 return true;157}158 159/**160 * async_xor_offs - attempt to xor a set of blocks with a dma engine.161 * @dest: destination page162 * @offset: dst offset to start transaction163 * @src_list: array of source pages164 * @src_offs: array of source pages offset, NULL means common src/dst offset165 * @src_cnt: number of source pages166 * @len: length in bytes167 * @submit: submission / completion modifiers168 *169 * honored flags: ASYNC_TX_ACK, ASYNC_TX_XOR_ZERO_DST, ASYNC_TX_XOR_DROP_DST170 *171 * xor_blocks always uses the dest as a source so the172 * ASYNC_TX_XOR_ZERO_DST flag must be set to not include dest data in173 * the calculation. The assumption with dma engines is that they only174 * use the destination buffer as a source when it is explicitly specified175 * in the source list.176 *177 * src_list note: if the dest is also a source it must be at index zero.178 * The contents of this array will be overwritten if a scribble region179 * is not specified.180 */181struct dma_async_tx_descriptor *182async_xor_offs(struct page *dest, unsigned int offset,183 struct page **src_list, unsigned int *src_offs,184 int src_cnt, size_t len, struct async_submit_ctl *submit)185{186 struct dma_chan *chan = async_tx_find_channel(submit, DMA_XOR,187 &dest, 1, src_list,188 src_cnt, len);189 struct dma_device *device = chan ? chan->device : NULL;190 struct dmaengine_unmap_data *unmap = NULL;191 192 BUG_ON(src_cnt <= 1);193 194 if (device)195 unmap = dmaengine_get_unmap_data(device->dev, src_cnt+1, GFP_NOWAIT);196 197 if (unmap && dma_xor_aligned_offsets(device, offset,198 src_offs, src_cnt, len)) {199 struct dma_async_tx_descriptor *tx;200 int i, j;201 202 /* run the xor asynchronously */203 pr_debug("%s (async): len: %zu\n", __func__, len);204 205 unmap->len = len;206 for (i = 0, j = 0; i < src_cnt; i++) {207 if (!src_list[i])208 continue;209 unmap->to_cnt++;210 unmap->addr[j++] = dma_map_page(device->dev, src_list[i],211 src_offs ? src_offs[i] : offset,212 len, DMA_TO_DEVICE);213 }214 215 /* map it bidirectional as it may be re-used as a source */216 unmap->addr[j] = dma_map_page(device->dev, dest, offset, len,217 DMA_BIDIRECTIONAL);218 unmap->bidi_cnt = 1;219 220 tx = do_async_xor(chan, unmap, submit);221 dmaengine_unmap_put(unmap);222 return tx;223 } else {224 dmaengine_unmap_put(unmap);225 /* run the xor synchronously */226 pr_debug("%s (sync): len: %zu\n", __func__, len);227 WARN_ONCE(chan, "%s: no space for dma address conversion\n",228 __func__);229 230 /* in the sync case the dest is an implied source231 * (assumes the dest is the first source)232 */233 if (submit->flags & ASYNC_TX_XOR_DROP_DST) {234 src_cnt--;235 src_list++;236 if (src_offs)237 src_offs++;238 }239 240 /* wait for any prerequisite operations */241 async_tx_quiesce(&submit->depend_tx);242 243 do_sync_xor_offs(dest, offset, src_list, src_offs,244 src_cnt, len, submit);245 246 return NULL;247 }248}249EXPORT_SYMBOL_GPL(async_xor_offs);250 251/**252 * async_xor - attempt to xor a set of blocks with a dma engine.253 * @dest: destination page254 * @src_list: array of source pages255 * @offset: common src/dst offset to start transaction256 * @src_cnt: number of source pages257 * @len: length in bytes258 * @submit: submission / completion modifiers259 *260 * honored flags: ASYNC_TX_ACK, ASYNC_TX_XOR_ZERO_DST, ASYNC_TX_XOR_DROP_DST261 *262 * xor_blocks always uses the dest as a source so the263 * ASYNC_TX_XOR_ZERO_DST flag must be set to not include dest data in264 * the calculation. The assumption with dma engines is that they only265 * use the destination buffer as a source when it is explicitly specified266 * in the source list.267 *268 * src_list note: if the dest is also a source it must be at index zero.269 * The contents of this array will be overwritten if a scribble region270 * is not specified.271 */272struct dma_async_tx_descriptor *273async_xor(struct page *dest, struct page **src_list, unsigned int offset,274 int src_cnt, size_t len, struct async_submit_ctl *submit)275{276 return async_xor_offs(dest, offset, src_list, NULL,277 src_cnt, len, submit);278}279EXPORT_SYMBOL_GPL(async_xor);280 281static int page_is_zero(struct page *p, unsigned int offset, size_t len)282{283 return !memchr_inv(page_address(p) + offset, 0, len);284}285 286static inline struct dma_chan *287xor_val_chan(struct async_submit_ctl *submit, struct page *dest,288 struct page **src_list, int src_cnt, size_t len)289{290 #ifdef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA291 return NULL;292 #endif293 return async_tx_find_channel(submit, DMA_XOR_VAL, &dest, 1, src_list,294 src_cnt, len);295}296 297/**298 * async_xor_val_offs - attempt a xor parity check with a dma engine.299 * @dest: destination page used if the xor is performed synchronously300 * @offset: des offset in pages to start transaction301 * @src_list: array of source pages302 * @src_offs: array of source pages offset, NULL means common src/det offset303 * @src_cnt: number of source pages304 * @len: length in bytes305 * @result: 0 if sum == 0 else non-zero306 * @submit: submission / completion modifiers307 *308 * honored flags: ASYNC_TX_ACK309 *310 * src_list note: if the dest is also a source it must be at index zero.311 * The contents of this array will be overwritten if a scribble region312 * is not specified.313 */314struct dma_async_tx_descriptor *315async_xor_val_offs(struct page *dest, unsigned int offset,316 struct page **src_list, unsigned int *src_offs,317 int src_cnt, size_t len, enum sum_check_flags *result,318 struct async_submit_ctl *submit)319{320 struct dma_chan *chan = xor_val_chan(submit, dest, src_list, src_cnt, len);321 struct dma_device *device = chan ? chan->device : NULL;322 struct dma_async_tx_descriptor *tx = NULL;323 struct dmaengine_unmap_data *unmap = NULL;324 325 BUG_ON(src_cnt <= 1);326 327 if (device)328 unmap = dmaengine_get_unmap_data(device->dev, src_cnt, GFP_NOWAIT);329 330 if (unmap && src_cnt <= device->max_xor &&331 dma_xor_aligned_offsets(device, offset, src_offs, src_cnt, len)) {332 unsigned long dma_prep_flags = 0;333 int i;334 335 pr_debug("%s: (async) len: %zu\n", __func__, len);336 337 if (submit->cb_fn)338 dma_prep_flags |= DMA_PREP_INTERRUPT;339 if (submit->flags & ASYNC_TX_FENCE)340 dma_prep_flags |= DMA_PREP_FENCE;341 342 for (i = 0; i < src_cnt; i++) {343 unmap->addr[i] = dma_map_page(device->dev, src_list[i],344 src_offs ? src_offs[i] : offset,345 len, DMA_TO_DEVICE);346 unmap->to_cnt++;347 }348 unmap->len = len;349 350 tx = device->device_prep_dma_xor_val(chan, unmap->addr, src_cnt,351 len, result,352 dma_prep_flags);353 if (unlikely(!tx)) {354 async_tx_quiesce(&submit->depend_tx);355 356 while (!tx) {357 dma_async_issue_pending(chan);358 tx = device->device_prep_dma_xor_val(chan,359 unmap->addr, src_cnt, len, result,360 dma_prep_flags);361 }362 }363 dma_set_unmap(tx, unmap);364 async_tx_submit(chan, tx, submit);365 } else {366 enum async_tx_flags flags_orig = submit->flags;367 368 pr_debug("%s: (sync) len: %zu\n", __func__, len);369 WARN_ONCE(device && src_cnt <= device->max_xor,370 "%s: no space for dma address conversion\n",371 __func__);372 373 submit->flags |= ASYNC_TX_XOR_DROP_DST;374 submit->flags &= ~ASYNC_TX_ACK;375 376 tx = async_xor_offs(dest, offset, src_list, src_offs,377 src_cnt, len, submit);378 379 async_tx_quiesce(&tx);380 381 *result = !page_is_zero(dest, offset, len) << SUM_CHECK_P;382 383 async_tx_sync_epilog(submit);384 submit->flags = flags_orig;385 }386 dmaengine_unmap_put(unmap);387 388 return tx;389}390EXPORT_SYMBOL_GPL(async_xor_val_offs);391 392/**393 * async_xor_val - attempt a xor parity check with a dma engine.394 * @dest: destination page used if the xor is performed synchronously395 * @src_list: array of source pages396 * @offset: offset in pages to start transaction397 * @src_cnt: number of source pages398 * @len: length in bytes399 * @result: 0 if sum == 0 else non-zero400 * @submit: submission / completion modifiers401 *402 * honored flags: ASYNC_TX_ACK403 *404 * src_list note: if the dest is also a source it must be at index zero.405 * The contents of this array will be overwritten if a scribble region406 * is not specified.407 */408struct dma_async_tx_descriptor *409async_xor_val(struct page *dest, struct page **src_list, unsigned int offset,410 int src_cnt, size_t len, enum sum_check_flags *result,411 struct async_submit_ctl *submit)412{413 return async_xor_val_offs(dest, offset, src_list, NULL, src_cnt,414 len, result, submit);415}416EXPORT_SYMBOL_GPL(async_xor_val);417 418MODULE_AUTHOR("Intel Corporation");419MODULE_DESCRIPTION("asynchronous xor/xor-zero-sum api");420MODULE_LICENSE("GPL");421