crypto/async_tx/async_memset.c

   1 /*
   2  * memory fill offload engine support
   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/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  *
  39  * honored flags: ASYNC_TX_ACK
  40  */
  41 struct dma_async_tx_descriptor *
  42 async_memset(struct page *dest, int val, unsigned int offset, size_t len,
  43              struct async_submit_ctl *submit)
  44 {
  45         struct dma_chan *chan = async_tx_find_channel(submit, DMA_MEMSET,
  46                                                       &dest, 1, NULL, 0, len);
  47         struct dma_device *device = chan ? chan->device : NULL;
  48         struct dma_async_tx_descriptor *tx = NULL;
  49
  50         if (device) {
  51                 dma_addr_t dma_dest;
  52                 unsigned long dma_prep_flags;
  53
  54                 dma_prep_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0;
  55                 dma_dest = dma_map_page(device->dev, dest, offset, len,
  56                                         DMA_FROM_DEVICE);
  57
  58                 tx = device->device_prep_dma_memset(chan, dma_dest, val, len,
  59                                                     dma_prep_flags);
  60         }
  61
  62         if (tx) {
  63                 pr_debug("%s: (async) len: %zu\n", __func__, len);
  64                 async_tx_submit(chan, tx, submit);
  65         } else { /* run the memset synchronously */
  66                 void *dest_buf;
  67                 pr_debug("%s: (sync) len: %zu\n", __func__, len);
  68
  69                 dest_buf = page_address(dest) + offset;
  70
  71                 /* wait for any prerequisite operations */
  72                 async_tx_quiesce(&submit->depend_tx);
  73
  74                 memset(dest_buf, val, len);
  75
  76                 async_tx_sync_epilog(submit);
  77         }
  78
  79         return tx;
  80 }
  81 EXPORT_SYMBOL_GPL(async_memset);
  82
  83 MODULE_AUTHOR("Intel Corporation");
  84 MODULE_DESCRIPTION("asynchronous memset api");
  85 MODULE_LICENSE("GPL");