diff options
Diffstat (limited to 'crypto/async_tx/async_xor.c')
| -rw-r--r-- | crypto/async_tx/async_xor.c | 327 |
1 files changed, 327 insertions, 0 deletions
diff --git a/crypto/async_tx/async_xor.c b/crypto/async_tx/async_xor.c new file mode 100644 index 0000000..2575f67 --- /dev/null +++ b/crypto/async_tx/async_xor.c @@ -0,0 +1,327 @@ +/* + * xor offload engine api + * + * Copyright © 2006, Intel Corporation. + * + * Dan Williams <dan.j.williams@intel.com> + * + * with architecture considerations by: + * Neil Brown <neilb@suse.de> + * Jeff Garzik <jeff@garzik.org> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. + * + */ +#include <linux/kernel.h> +#include <linux/interrupt.h> +#include <linux/mm.h> +#include <linux/dma-mapping.h> +#include <linux/raid/xor.h> +#include <linux/async_tx.h> + +static void +do_async_xor(struct dma_async_tx_descriptor *tx, struct dma_device *device, + struct dma_chan *chan, struct page *dest, struct page **src_list, + unsigned int offset, unsigned int src_cnt, size_t len, + enum async_tx_flags flags, struct dma_async_tx_descriptor *depend_tx, + dma_async_tx_callback cb_fn, void *cb_param) +{ + dma_addr_t dma_addr; + enum dma_data_direction dir; + int i; + + pr_debug("%s: len: %zu\n", __FUNCTION__, len); + + dir = (flags & ASYNC_TX_ASSUME_COHERENT) ? + DMA_NONE : DMA_FROM_DEVICE; + + dma_addr = dma_map_page(device->dev, dest, offset, len, dir); + tx->tx_set_dest(dma_addr, tx, 0); + + dir = (flags & ASYNC_TX_ASSUME_COHERENT) ? + DMA_NONE : DMA_TO_DEVICE; + + for (i = 0; i < src_cnt; i++) { + dma_addr = dma_map_page(device->dev, src_list[i], + offset, len, dir); + tx->tx_set_src(dma_addr, tx, i); + } + + async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param); +} + +static void +do_sync_xor(struct page *dest, struct page **src_list, unsigned int offset, + unsigned int src_cnt, size_t len, enum async_tx_flags flags, + struct dma_async_tx_descriptor *depend_tx, + dma_async_tx_callback cb_fn, void *cb_param) +{ + void *_dest; + int i; + + pr_debug("%s: len: %zu\n", __FUNCTION__, len); + + /* reuse the 'src_list' array to convert to buffer pointers */ + for (i = 0; i < src_cnt; i++) + src_list[i] = (struct page *) + (page_address(src_list[i]) + offset); + + /* set destination address */ + _dest = page_address(dest) + offset; + + if (flags & ASYNC_TX_XOR_ZERO_DST) + memset(_dest, 0, len); + + xor_blocks(src_cnt, len, _dest, + (void **) src_list); + + async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param); +} + +/** + * async_xor - attempt to xor a set of blocks with a dma engine. + * xor_blocks always uses the dest as a source so the ASYNC_TX_XOR_ZERO_DST + * flag must be set to not include dest data in the calculation. The + * assumption with dma eninges is that they only use the destination + * buffer as a source when it is explicity specified in the source list. + * @dest: destination page + * @src_list: array of source pages (if the dest is also a source it must be + * at index zero). The contents of this array may be overwritten. + * @offset: offset in pages to start transaction + * @src_cnt: number of source pages + * @len: length in bytes + * @flags: ASYNC_TX_XOR_ZERO_DST, ASYNC_TX_XOR_DROP_DEST, + * ASYNC_TX_ASSUME_COHERENT, ASYNC_TX_ACK, ASYNC_TX_DEP_ACK + * @depend_tx: xor depends on the result of this transaction. + * @cb_fn: function to call when the xor completes + * @cb_param: parameter to pass to the callback routine + */ +struct dma_async_tx_descriptor * +async_xor(struct page *dest, struct page **src_list, unsigned int offset, + int src_cnt, size_t len, enum async_tx_flags flags, + struct dma_async_tx_descriptor *depend_tx, + dma_async_tx_callback cb_fn, void *cb_param) +{ + struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_XOR); + struct dma_device *device = chan ? chan->device : NULL; + struct dma_async_tx_descriptor *tx = NULL; + dma_async_tx_callback _cb_fn; + void *_cb_param; + unsigned long local_flags; + int xor_src_cnt; + int i = 0, src_off = 0, int_en; + + BUG_ON(src_cnt <= 1); + + while (src_cnt) { + local_flags = flags; + if (device) { /* run the xor asynchronously */ + xor_src_cnt = min(src_cnt, device->max_xor); + /* if we are submitting additional xors + * only set the callback on the last transaction + */ + if (src_cnt > xor_src_cnt) { + local_flags &= ~ASYNC_TX_ACK; + _cb_fn = NULL; + _cb_param = NULL; + } else { + _cb_fn = cb_fn; + _cb_param = cb_param; + } + + int_en = _cb_fn ? 1 : 0; + + tx = device->device_prep_dma_xor( + chan, xor_src_cnt, len, int_en); + + if (tx) { + do_async_xor(tx, device, chan, dest, + &src_list[src_off], offset, xor_src_cnt, len, + local_flags, depend_tx, _cb_fn, + _cb_param); + } else /* fall through */ + goto xor_sync; + } else { /* run the xor synchronously */ +xor_sync: + /* in the sync case the dest is an implied source + * (assumes the dest is at the src_off index) + */ + if (flags & ASYNC_TX_XOR_DROP_DST) { + src_cnt--; + src_off++; + } + + /* process up to 'MAX_XOR_BLOCKS' sources */ + xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS); + + /* if we are submitting additional xors + * only set the callback on the last transaction + */ + if (src_cnt > xor_src_cnt) { + local_flags &= ~ASYNC_TX_ACK; + _cb_fn = NULL; + _cb_param = NULL; + } else { + _cb_fn = cb_fn; + _cb_param = cb_param; + } + + /* wait for any prerequisite operations */ + if (depend_tx) { + /* if ack is already set then we cannot be sure + * we are referring to the correct operation + */ + BUG_ON(depend_tx->ack); + if (dma_wait_for_async_tx(depend_tx) == + DMA_ERROR) + panic("%s: DMA_ERROR waiting for " + "depend_tx\n", + __FUNCTION__); + } + + do_sync_xor(dest, &src_list[src_off], offset, + xor_src_cnt, len, local_flags, depend_tx, + _cb_fn, _cb_param); + } + + /* the previous tx is hidden from the client, + * so ack it + */ + if (i && depend_tx) + async_tx_ack(depend_tx); + + depend_tx = tx; + + if (src_cnt > xor_src_cnt) { + /* drop completed sources */ + src_cnt -= xor_src_cnt; + src_off += xor_src_cnt; + + /* unconditionally preserve the destination */ + flags &= ~ASYNC_TX_XOR_ZERO_DST; + + /* use the intermediate result a source, but remember + * it's dropped, because it's implied, in the sync case + */ + src_list[--src_off] = dest; + src_cnt++; + flags |= ASYNC_TX_XOR_DROP_DST; + } else + src_cnt = 0; + i++; + } + + return tx; +} +EXPORT_SYMBOL_GPL(async_xor); + +static int page_is_zero(struct page *p, unsigned int offset, size_t len) +{ + char *a = page_address(p) + offset; + return ((*(u32 *) a) == 0 && + memcmp(a, a + 4, len - 4) == 0); +} + +/** + * async_xor_zero_sum - attempt a xor parity check with a dma engine. + * @dest: destination page used if the xor is performed synchronously + * @src_list: array of source pages. The dest page must be listed as a source + * at index zero. The contents of this array may be overwritten. + * @offset: offset in pages to start transaction + * @src_cnt: number of source pages + * @len: length in bytes + * @result: 0 if sum == 0 else non-zero + * @flags: ASYNC_TX_ASSUME_COHERENT, ASYNC_TX_ACK, ASYNC_TX_DEP_ACK + * @depend_tx: xor depends on the result of this transaction. + * @cb_fn: function to call when the xor completes + * @cb_param: parameter to pass to the callback routine + */ +struct dma_async_tx_descriptor * +async_xor_zero_sum(struct page *dest, struct page **src_list, + unsigned int offset, int src_cnt, size_t len, + u32 *result, enum async_tx_flags flags, + struct dma_async_tx_descriptor *depend_tx, + dma_async_tx_callback cb_fn, void *cb_param) +{ + struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_ZERO_SUM); + struct dma_device *device = chan ? chan->device : NULL; + int int_en = cb_fn ? 1 : 0; + struct dma_async_tx_descriptor *tx = device ? + device->device_prep_dma_zero_sum(chan, src_cnt, len, result, + int_en) : NULL; + int i; + + BUG_ON(src_cnt <= 1); + + if (tx) { + dma_addr_t dma_addr; + enum dma_data_direction dir; + + pr_debug("%s: (async) len: %zu\n", __FUNCTION__, len); + + dir = (flags & ASYNC_TX_ASSUME_COHERENT) ? + DMA_NONE : DMA_TO_DEVICE; + + for (i = 0; i < src_cnt; i++) { + dma_addr = dma_map_page(device->dev, src_list[i], + offset, len, dir); + tx->tx_set_src(dma_addr, tx, i); + } + + async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param); + } else { + unsigned long xor_flags = flags; + + pr_debug("%s: (sync) len: %zu\n", __FUNCTION__, len); + + xor_flags |= ASYNC_TX_XOR_DROP_DST; + xor_flags &= ~ASYNC_TX_ACK; + + tx = async_xor(dest, src_list, offset, src_cnt, len, xor_flags, + depend_tx, NULL, NULL); + + if (tx) { + if (dma_wait_for_async_tx(tx) == DMA_ERROR) + panic("%s: DMA_ERROR waiting for tx\n", + __FUNCTION__); + async_tx_ack(tx); + } + + *result = page_is_zero(dest, offset, len) ? 0 : 1; + + tx = NULL; + + async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param); + } + + return tx; +} +EXPORT_SYMBOL_GPL(async_xor_zero_sum); + +static int __init async_xor_init(void) +{ + return 0; +} + +static void __exit async_xor_exit(void) +{ + do { } while (0); +} + +module_init(async_xor_init); +module_exit(async_xor_exit); + +MODULE_AUTHOR("Intel Corporation"); +MODULE_DESCRIPTION("asynchronous xor/xor-zero-sum api"); +MODULE_LICENSE("GPL"); |