LXR linux/crypto/async_tx/async

   1/*
   2 * memory fill offload engine support
   3 *
   4 * Copyright \xC2\xA9 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/async_tx.h>
  31
  32/**
  33 * async_memset - attempt to fill memory with a dma engine.
  34 * @dest: destination page
  35 * @val: fill value
  36 * @offset: offset in pages to start transaction
  37 * @len: length in bytes
  38 * @flags: ASYNC_TX_ASSUME_COHERENT, ASYNC_TX_ACK, ASYNC_TX_DEP_ACK
  39 * @depend_tx: memset depends on the result of this transaction
  40 * @cb_fn: function to call when the memcpy completes
  41 * @cb_param: parameter to pass to the callback routine
  42 */
  43struct dma_async_tx_descriptor *
  44async_memset(struct page *dest, int val, unsigned int offset,
  45        size_t len, enum async_tx_flags flags,
  46        struct dma_async_tx_descriptor *depend_tx,
  47        dma_async_tx_callback cb_fn, void *cb_param)
  48{
  49        struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_MEMSET);
  50        struct dma_device *device = chan ? chan->device : NULL;
  51        int int_en = cb_fn ? 1 : 0;
  52        struct dma_async_tx_descriptor *tx = device ?
  53                device->device_prep_dma_memset(chan, val, len,
  54                        int_en) : NULL;
  55
  56        if (tx) { /* run the memset asynchronously */
  57                dma_addr_t dma_addr;
  58                enum dma_data_direction dir;
  59
  60                pr_debug("%s: (async) len: %zu\n", __FUNCTION__, len);
  61                dir = (flags & ASYNC_TX_ASSUME_COHERENT) ?
  62                        DMA_NONE : DMA_FROM_DEVICE;
  63
  64                dma_addr = dma_map_page(device->dev, dest, offset, len, dir);
  65                tx->tx_set_dest(dma_addr, tx, 0);
  66
  67                async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param);
  68        } else { /* run the memset synchronously */
  69                void *dest_buf;
  70                pr_debug("%s: (sync) len: %zu\n", __FUNCTION__, len);
  71
  72                dest_buf = (void *) (((char *) page_address(dest)) + offset);
  73
  74                /* wait for any prerequisite operations */
  75                if (depend_tx) {
  76                        /* if ack is already set then we cannot be sure
  77                         * we are referring to the correct operation
  78                         */
  79                        BUG_ON(depend_tx->ack);
  80                        if (dma_wait_for_async_tx(depend_tx) == DMA_ERROR)
  81                                panic("%s: DMA_ERROR waiting for depend_tx\n",
  82                                        __FUNCTION__);
  83                }
  84
  85                memset(dest_buf, val, len);
  86
  87                async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param);
  88        }
  89
  90        return tx;
  91}
  92EXPORT_SYMBOL_GPL(async_memset);
  93
  94static int __init async_memset_init(void)
  95{
  96        return 0;
  97}
  98
  99static void __exit async_memset_exit(void)
 100{
 101        do { } while (0);
 102}
 103
 104module_init(async_memset_init);
 105module_exit(async_memset_exit);
 106
 107MODULE_AUTHOR("Intel Corporation");
 108MODULE_DESCRIPTION("asynchronous memset api");
 109MODULE_LICENSE("GPL");
 110