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  * @flags: 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  */
  43 struct dma_async_tx_descriptor *
  44 async_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         struct dma_async_tx_descriptor *tx = NULL;
  52
  53         if (device) {
  54                 dma_addr_t dma_dest;
  55
  56                 dma_dest = dma_map_page(device->dev, dest, offset, len,
  57                                         DMA_FROM_DEVICE);
  58
  59                 tx = device->device_prep_dma_memset(chan, dma_dest, val, len,
  60                                                     cb_fn != NULL);
  61         }
  62
  63         if (tx) {
  64                 pr_debug("%s: (async) len: %zu\n", __FUNCTION__, len);
  65                 async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param);
  66         } else { /* run the memset synchronously */
  67                 void *dest_buf;
  68                 pr_debug("%s: (sync) len: %zu\n", __FUNCTION__, len);
  69
  70                 dest_buf = (void *) (((char *) page_address(dest)) + offset);
  71
  72                 /* wait for any prerequisite operations */
  73                 if (depend_tx) {
  74                         /* if ack is already set then we cannot be sure
  75                          * we are referring to the correct operation
  76                          */
  77                         BUG_ON(depend_tx->ack);
  78                         if (dma_wait_for_async_tx(depend_tx) == DMA_ERROR)
  79                                 panic("%s: DMA_ERROR waiting for depend_tx\n",
  80                                         __FUNCTION__);
  81                 }
  82
  83                 memset(dest_buf, val, len);
  84
  85                 async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param);
  86         }
  87
  88         return tx;
  89 }
  90 EXPORT_SYMBOL_GPL(async_memset);
  91
  92 static int __init async_memset_init(void)
  93 {
  94         return 0;
  95 }
  96
  97 static void __exit async_memset_exit(void)
  98 {
  99         do { } while (0);
 100 }
 101
 102 module_init(async_memset_init);
 103 module_exit(async_memset_exit);
 104
 105 MODULE_AUTHOR("Intel Corporation");
 106 MODULE_DESCRIPTION("asynchronous memset api");
 107 MODULE_LICENSE("GPL");