summaryrefslogtreecommitdiffstats
path: root/crypto/async_tx/async_xor.c
diff options
context:
space:
mode:
Diffstat (limited to 'crypto/async_tx/async_xor.c')
-rw-r--r--crypto/async_tx/async_xor.c327
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");
OpenPOWER on IntegriCloud